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  • 1
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Summary Natural societies ofPlagiolepis pygmaea were collected at the end of the winter period. Usually, they were strongly polygynous (17 queens per society in average) All the wingless queens were inseminated and could lay eggs. The weight of these queens is correlated: - negatively with their number in the societies; - positively with the number of nurse workers; - positively with their ovary development. The queens' fecundity has been studied in monogynous condition by counting the number of eggs laid during 5 weeks at the end of the winter period. Several correlations were revealed: - a positive one between the queen's fecundity and their weight; - a positive one between the queen's fecundity and their aggregative power on their workers; - a negative one between the queen's fecundity and their number in their native society.
    Notes: Resume Les sociétés naturelles dePlagiolepis pygmaea récoltées à la fin de l'hivernage sont habituellement fortement polygynes (en moyenne 17 reines par société). Toutes les reines désailées sont inséminées et participent à la ponte. Ces reines présentent certaines particularités en relation avec les caractéristiques démographiques des sociétés; en particulier, leur poids montre une corrélation: - négative avec leur nombre dans la société; - positive avec le nombre d'ouvrières nourrices; - positive avec le développement de leurs ovaires. La fécondité des reines a été étudiée en condition expérimentale monogyne en dénombrant les œufs pondus pendant 5 semaines à la fin de l'hivernage. On met en évidence plusieurs corrélations: - positive entre la fécondité et le poids des reines; - positive entre la fécondité et le pouvoir agrégatif des reines sur leurs ouvrières; - négative entre la fécondité et le degré de polygynie de la société d'origine.
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  • 2
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Resume La fourmi primitiveAneuretus simoni a été recherchée au Sri Lanka dans les forêts de Kandy, Matale, Peradeniya, Gilimale et Ratnapura. Des sociétés de l'espèce ont pu être trouvées dans les seules forêts humides de Gilimale. La répartition de cette fourmi semble localisée aux zones d'altitudes supérieures à 450 m recevant de 2 à 5 mètres d'eau par an. Au total, 33 sociétés ont pu être récoltées, dont plusieurs avec des reines. Les densités des sociétés étaient respectivement de 0.017, 0.023 et 0.033 soc/m2 dans les 3 sites étudiés. Nous avons dénombré chezA. simoni une moyenne de 65 ouvrières minor et une ou plusieurs reines par société. Les ouvrières major ne représentent que 2 à 3 % des effectifs. Les sexués apparaissent du milieu du mois de juillet au mois d'août. La société semble polycalique. Dans leur habitat habituel, les ouvrières sont omnivores. Elles consomment des petits insectes et des hydrates de carbone prélevés sur des fruits pourrissants. Un système de pistes de récoltes est utilisé dans l'exploitation de sources de nourriture importantes. Les ouvrières d'A. simoni évitent typiquement tout contact avec celles de fourmis sympatriques commePheidole, Paratrechina, Tetramorium, Odontomachus etMonomorium. En cas de rencontre avec des ouvrières étrangères de la même espèce, il en résulte des phénomènes d'agression. Ceci suggère que la reconnaissance des congénères d'une même société et peut être l'existence d'un comportement territorial intraspécifique semblent bien développés.
    Notes: Summary A search forAneuretus simoni was carried out in forested regions near Kandy, Matale, Peradeniya, Gilimale, Ratnapura, and Lagumba, Sri Lanka. Colonies were found only in the humid forests of the Gilimale area. The distribution ofA. simoni appears to be correlated with rainfall (200–500 cm/year) and geographic elevation (above 450 meters). A total of 33 queenright and queenless nests were collected. Nest density was 0.017, 0.023, and 0.033 colonies/m2, respectively, in three study plots. Aneuretus colonies contain on average more than one queen and approximately 65 minor workers. Major workers comprise only two to three percent of the colony population. Sexuals are found in nests from mid-July to August. Colonies appear to be polydomous. A. simoni workers observed in the field showed generalized foraging habits. They preyed upon small insects and collected carbohydrate from rotting fruit. Trail systems were used in exploitation of large food sources. A. simoni workers typically avoid contact with workers of sympatric ant genera such asPheidole, Paratrechina, Tetramorium, Odontomachus, andMonomorium. When alien conspecifics are encountered, aggression results, indicating that nestmate recognition and perhaps intraspecific territoriality is well developed.
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  • 3
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    Insectes sociaux 32 (1985), S. 209-212 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Summary Pimelic and azelaic acids are major constituants of the survivone which induces a prolongation of life in isolated bees. Their action is dependent of age of bees and of the season; azelaic acid is more efficient in summer and winter; pimelic acid in spring.
    Notes: Resume Les acides azélaïque et pimélique sont des constituants majeurs de la survivone, phéromone de survie les abeilles isolées. Leur action dépend de la saison, l'acide azélaïque étant plus efficace sur la survie des abeilles d'été et d'hiver, et l'acide pimélique sur la survie des abeilles de printemps.
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  • 4
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    Insectes sociaux 33 (1986), S. 118-131 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Resume 1. La distribution des individus de groupes normaux deMyrmica rubra a été étudiée dans des nids artificiels formés d'une seule rangée de cellules. Une couche d'ouvrières recouvre les reines et le couvain, ménageant cependant une région périphérique où l'on ne trouve que des ouvrières dont le rôle est de défendre l'entrée et de préparer les proies pour la consommation. La région périphérique est particulièrement bien représentée, près de l'entrée. Lorsque le paquet d'œufs grossit, l'enveloppe d'ouvrières se dissocie et découvre les larves; lorsque ces dernières sont prêtes à se nymphoser, les ouvrières les ramènent vers le centre où se trouvent le couvain non alimenté et les reines. 2. La sociabilité des reines est très variable. Certaines restent seules la plupart du temps alors que d'autres sont rarement solitaires et se regroupent avec d'autres reines. Certaines des reines sociables peuvent être très attentives au choix de leurs compagnes alors que d'autres sont tout à fait indifférentes à leur voisinage. Toutes les reines pondent des œufs en nombre variable sans rapport avec leur degré de sociabilité.
    Notes: Summary 1. The form of normal groups ofMyrmica rubra has been studied in artificial nests consisting of a single tier of cells. An envelope of workers spreads out and covers the queens and brood leaving a cortex composed only of workers that functions as a defensive zone and a zone in which prey are prepared for ingestion. The cortex is especially well developed near the entrance. As the egg cluster grows, it breaks up, often with worker help and releases larvae; when these are ready to pupate the workers take them back into the central core of non-feeding brood and queens. 2. The sociability of queens varies from those that are often alone, to those that are rarely alone and spend most of their time with other queens. Sociable queens may be very specific in the individuals they associate with or very indifferent to their companions. All the queens lay eggs in variable numbers but the quantity is not related to their sociability.
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  • 5
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Auf der Insel Negros, Philippinen, wurde ein aus Bambus gebautes Bauernhaus entdeckt, das mindestens 84 Kolonien von stachellosen Bienen beherbergte, und zwar der beiden ArtenTrigona (Tetragonula) fuscobalteata undT. (Tetragonula) sapiens in einem Verhältnis von ungefähr 3∶1. Die Nester waren in Bambussegmenten, je mit einem Rauminhalt von 0,7–3,0 1. Die Neststruktur entspricht generell dem Typus der Unterfamilie. Die Flugröhre ist einfach und nicht besonders lang. Die Röhrenöffnung ist beiT. sapiens länger und enger als beiT. fuscobalteata, obwohlT. sapiens einen breiteren Kopf besitzt. Die Brutzellen sind nicht in Waben angeordnet, sondern bilden traubenförmige Haufen. Sie sind auch nicht von einem Involucrum umgegeben. Es gibt Hinweise, daß stachellosen Bienen in trockenen Gebieten der Philippinen häufiger vorkommen.
    Notes: Summary A bamboo farmhouse on Negros island, Philippines harbored at least 84 colonies ofTrigona (Tetragonula) fuscobalteata andT. (Tetragonula) sapiens in a ratio of about 3∶1. Nests were in bamboo stem cavities of 0.7–3.0 1 volume. In neither species does The nest show specialized features relative to the subfamily. The entrance tube is simple and of medium length. The tube aperture is longer and narrower inT. sapiens thanT. fuscobalteata, although the former species has a greater head-width. Brood-cells are arranged in clusters, not in organized combs, and are not surrounded by an involucrum. p There is some indication that within the Philippines stingless bees are more abundant in drier areas.
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  • 6
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    Insectes sociaux 34 (1987), S. 118-130 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Resume L'influence de la taille des ouvrières et du comportement coopératif sur l'activité de récolte a été analysé chez 4 fourmis communes de prairie de la zone tempérée nordaméricaine:Lasius neoniger, Formica schaufussi, Myrmica americana, etMonomorium minimum. Les niches de ces espèces se recouvrent au niveau de la taille de leurs proies (arthropodes) et de leur activité temporelle de récolte. Les arthropodes sont ramenés par des fourrageuses solitaires ou par des groupes d'ouvrières qui coopèrent. Les espèces diffèrent par les proportions de proies ramenées suivant l'une ou l'autre méthode. Dans le cas du transport solitaire, la taille des proies est corrélée à celle des fourrageuses, mais cette corrélation disparaît dans le cas du transport coopératif. Enfin, il est discuté les différentes stratégies sociales de fourragement et l'évolution de la taille des ouvrières.
    Notes: Summary The common North Temperate open-field antsLasius neoniger, Formica schaufussi, Myrmica americana, andMonomorium minimum overlap temporally in foraging activity as well as in the sizes of arthropod prey in their diets. Arthropod prey were taken by both individual workers and cooperative worker groups, and species differed in the proportion of prey in the diet retrieved by each method. Although prey size was significantly correlated with worker size for individually retrieved prey, when cooperative foraging was considered worker size did not serve as a consistent predictor of prey choice. Contrasting social strategies of foraging and the evolution of worker body size differences are discussed.
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  • 7
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Resume L'électrophorèse en gel d'amidon de 8 enzymes codées par différents loci a permis de déduire, chez l'Abeille primitivement eusocialeDialictus zephyrus, les génotypes de 31 fondatrices, apparemment solitaires, et de leur couvain de première génération. 13% des sociétés renfermaient une descendance provenant de plus d'une femelle et 23% la descendance soit de plus d'une femelle, soit d'une seule femelle fécondée à deux reprises. Ainsi, un total de 36% des sociétés apparemment fondées par une femelle unique contenaient des descendants de première génération qui ne pouvaient provenir d'une femelle, fécondée une fois pour toutes.
    Notes: Summary Genotypes for 31 apparent, single foundresses and their first generation brood in the primitively eusocial sweat beeDialictus zephyrus were inferred from starch-gel electrophoresis of 8 enzyme coding loci. Thirteen percent of the colonies contained the progeny of more than one female, and an additional twenty-three percent contained the progeny of either more than one female or a single, twice-mated female. Thus a total of thirty-six percent of colonies apparently founded by a single female contained first generation brood which were not the progeny of one, singly-mated female.
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  • 8
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    Insectes sociaux 34 (1987), S. 229-235 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Resume Les ouvriers affamés deCoptotermes formosanus prennent l'initiative des échanges trophallactiques avec les soldats, quel que soit l'état nutritionnel de ceux-ci. Les soldats affamés ne sollicitent pas de nourriture des ouvriers, et ne sont pas nourris par eux quand ces ouvriers sont alimentés préalablement. Les résultats de laboratoire suggèrent que l'échange ouvrier-soldat est un comportement toujours initié par l'ouvrier et indépendant de létat nutrionnel du soldat.
    Notes: Summary Starved workers of the Formosan subterranean termite,Coptotermes formosanus Shiraki, initiated trophallactic exchanges with soldiers regardless of soldier nutritional status. Starved soldiers did not solicit food from workers and were not fed when workers had been fed previously. The laboratory results suggest that worker-soldier trophallactic exchange is a worker-initiated behavior and essentially independent of the nutritional state of the soldier.
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  • 9
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    Insectes sociaux 34 (1987), S. 252-260 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Geschlechtsphromone wurden bei sechs japanischenVespa-Arten in Laborversuchen nachgewiesen, wobei sowohl intakte Königinnen wie auch deren Atherextrakte getestet wurden. Eine deutliche interspezifische Wirksamkeit der Pheromone wurde bei allen paarweisen Kombinationen zwischen fünf der sechs sympatrischen rten gefunden, und zwar beiV. analis, V. mandarina, V. tropica, V. simillima xanthoptera undV. crabro.
    Notes: Summary The presence of sex pheromones in six Japanese species of the genusVespa was demonstrated by laboratory assyas using intact queens and their ether extracts. Clear interspecific cross-activities of the pheromones was found for all pairwise combinations between five of the six sympatric species,V. analis, V. mandarinia, V. tropica, V. simillima xanthoptera andV. crabro.
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  • 10
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    Insectes sociaux 34 (1987), S. 136-141 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Resume Afin de déterminer le rôle de l'expérience sociale précoce sur l'ontogenèse de la reconnaissance des cocons par une espèce esclave de fourmi, des expériences de laboratoire ont été réalisées surFormica cunicularia, une espèce communément esclave deFormica sanguinea. Dans un test de choix, des ouvrières adultes deF. cunicularia provenant d'une colonie pure soignèrent uniquement des cocons homospécifiques, tandis qu'elles détruisirent les cocons hétérospécifiques, non familiers (F. sanguinea etF. lugubris). Après quoi, 3 groupes de colonies artificielles ont été constitués avec de jeunes ouvrières deF. cunicularia de même âge, retirées expérimentalement de leurs cocons. Après une période d'entraînement de quinze jours avec des cocons homospécifiques (groupe C), des cocons deF. sanguinea (groupe T), on en l'absence de tout cocon (groupe I), ces ouvrières furent soumises à un test de choix entre des cocons deF. cunicularia et deF. sanguinea. Le choix des ouvrières des groupes C et T fut toujours en faveur des cocons auxquels elles avaient été familiarisées au cours de la période d'entraînement. En outre, la privation des cocons rompit la discrimination des cocons et l'aptitude aux soins des fourmis du groupe I. Sur la base de ces données et de celles que nous avons obtenues récemment sur la reconnaissance des partenaires du nid chez la même espèce, nous pouvons soutenir que l'expérience sociale suivant immédiatement l'éclosion chez l'ouvrière deF. cunicularia peut expliquer son esclavage dans la nature et, par conséquent, l'altruisme interspécifique de cet hôte à l'égard de son parasite.
    Notes: Summary In order to determine the role of early social experience on the ontogeny of cocoon recognition by a slave-ant species, laboratory experiments were carried out inFormica cunicularia, a common slave ofFormica sanguinea. In a choice-test, adultF. cunicularia workers coming from a pure colony tended only the homospecific cocoons, whereas destroyed the heterospecific unfamiliar ones (F. sanguinea andF. lugubris). Subsequently, 3 groups of artificial colonies were set up with callowF. cunicularia workers of the same age experimentally removed from their cocoons. After a 15-day training period with homospecific cocoons (group C),F. sanguinea cocoons (group T), or in absence of any cocoons (group I), these workers were given a choice-test betweenF. cunicularia andF. sanguinea cocoons. The choice of the workers belonging to groups C and T was always directed towards the cocoons with which workers had become familiar during the training period. Moreover, early deprivation of cocoons disrupted the cocoon discrimination and care ability of ants belonging to group I. On the basis of these data and those recently obtained by us on nestmate recognition in the same species, we can assume that social experience immediately following eclosion ofF. cunicularia workers can fully explain their enslavement in nature and, therefore, the interspecific altruism of this host species towards the parasite.
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  • 11
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Resume Les populations des nids croissent rapidement dans la phase juvénile, puis deviennent stables à maturité. Les relations entre les paramètres de la population, et les poids de la reine et des meules à champignons, sont approximativement linéaires pour tous les composants, les soldats et les présoldats exceptés. Les relations entre les paramètres des nids et leurs populations sont approximativement linéaires. Par conséquent, on peut estimer les populations des termites à partir des études de ces paramètres et densités de nids.
    Notes: Summary Nest populations grow rapidly while the nest is young, then stabilise to a fairly constant level in maturity. Relationships between population parameters, queen's weight and fungus comb weight are all approximately linear, with the exception of soldier and presoldiers numbers. Relationships between mound parameters and nest population are approximately linear, so that data from surveys of mound size and density can be used to estimate termite populations.
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  • 12
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    Insectes sociaux 34 (1987), S. 194-203 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Resume La sex-ratio de l'investissement reproductif (SRI) ou la fréquence de l'investissement mâle (IFS) ont été évaluées au niveau de la population et des colonies dans des populations des fourmisL. alienus, L. niger et leurs hybrides. Une plus grande similarité a été notée entre l'IFS correspondant àL. alienus et aux hybrides qu'entre ces derniers et l'IFS deL. niger. Ceci a été étudié en rapport avec la compatibilkités de cette information avec des prédictions reposant sur la caste et le conflit intra- (dans le cas des ouvrières) et inter-castes comme déterminants de IF. Une évaluation de la relation des ouvrières entre elles à l'inteérieur d'une même colonie dans une population de fourmisL. alienus a été significativement supérieure à zéro. Bien qu'étant en accord avec la structure monogyne attribuée à cette espèce les limites de confiance au seuil de 95% du degré de relation pourrait aussi correspondre à un certain degré de polygynie et/ou de fécondation multiple.
    Notes: Summary The sex ratio of investment (SRI) or male investment frequencies (IFs) were estimated at the population and colony level in populations ofL. alienus, L. niger and their hybrids. More simlarity betweenL. alienus IFs and the hybrid IFs than between compatibility of these data with predictions dependent on the caste or intra (in the instance of workers) and inter caste conflict as determinants of the IF. An estimate of intra colonial, worker relatedness in aL. alienus population was significantly greater than zero. Whilst being consistent with the monogynous structure attributed to this species the 95% confidence limits of the relatedness value would also accommodate a degree of polygyny and/or multipe mating.
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  • 13
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    Insectes sociaux 34 (1987), S. 181-193 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Resume La présence simultanée de plusieurs reines d'abeilles vierges, hors de leurs cellules, est empêchée, dans la période précédant l'essaimage, par un retar de l'émergence de toutes les reines, sauf une. De cette manière le combat entre reines est évité. Les processus responsables de ce retard ont été étudiés. La transmission du «tooting», son produit par la reine vierge hors de la cellule, a été analysée. Des reines prêtes à émerger percent l'extrémité inférieure de leur cellule. Chez des reines isolées cette activité a été interrompue par l'émission du «tooting» enregistré. Par conséquent leur sortie a été retardée de plusieurs heures. En outre, si les cellules royales étaient exposées au «tooting» au sein d'une ruche d'observation, l'émergence des reines était beaucoup plus retardée, parce que, dans ce cas, les ouvrières enferment les reines dans leur cellule. Le rôle des danses vibrantes dans cet enfermement, comportement souvent observé sur des cellules de reines prêtes à sortir, a été recherché, sans pourvoir être prouvé. On a constaté qu'un élément important du comportement des ouvrières au cours de l'enfermement était la fermeture des petits trous percés par la reine dans le bout de la cellule. Les incisions dans les cellules royales étaient refermées à la même vitesse avant et après la période de transmission du «tooting». La fermeture n'est donc pas influencée par le «tooting». On considère que le «tooting» et la fermeture des cellules par des ouvrières ne peuvent pas séparément retarder longuement la sortie des reines. Leur présence combinée est essentielle: le «tooting» inhibe l'activité des reines d'une manière suffisante pour que les ouvrières puissent empêcher leur sortie pendant quelques jours.
    Notes: Summary In honey bees the simultaneous presence of several emerged virgin queens in the period preceding afterswarming, is prevented by a delay of emergence of all queens but one. It this way fighting between queens is avoided. The processes responsible for this delay were studied. The significance of the tooting sounds produced by the emerged virgin queen was examined. Queens ready to emerge cut a cap of their cells. In isolated queens this activity was interrupted by replay of recorded tooting. Consequently their emergence was delayed for several hours. If, however, queen cells in observation hives were exposed to tooting, the emergence of queens was much more delayed, because in this situation worker bees confine the queens in their cells. The confining effect of vibratory dances, a worker behaviour often observed on cells with queens ready to emerge, was explored, but could not be demonstrated. An important element of worker behaviour, effectuating confinement, appeared to be the sealing of cuts made by the enclosed queens in their cell caps. Incisions in queen cells were closed at the same rate before and after a 24 h period of transmission of tooting, so sealing is not influenced by the presence of tooting. It is argued that separately tooting and sealing by workers cannot cause a long term delay of emergence of queens. Their combined presence is essential: tooting inhibits the activity of queens sufficiently to enable the workers to obstruct their emergence for days.
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  • 14
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    Insectes sociaux 34 (1987), S. 143-164 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Die AmeisePrenolepis imparis Say ist in Nord-Florida (USA) nur im Winter an der Erdoberfläche aktiv. Das Sammeln von Nahrung beginnt im November und endet im März oder Anfang April; danach verschließen die Arbeiterinnen das Nest bis zum November. Während der Periode des Nahrungssammelns wird die Gaster der Arbeiterinnen enorm dick, so daß das Gewicht dieser Arbeiterinnen sich verdoppelt oder verdreifacht. Die Gewichtszunahme wird durch den stark entwickelten Fettkörper verursacht und nicht durch die Füllung des Kropfes, wie man früher glaubte. Die Kolonie zieht bis Ende August oder Anfang September keine Brut auf, erst dann beginnen sich die Ovarien der Königin zu entwickeln und sie legt Eier. Diese Brut wird wahrscheinlich mit einem Sekret ernährt, für das die Energiespeicher der dicken Arbeiterinnen mobilisiert werden. Wenn die Nester im November wieder geöffnet werden, dann besteht der größte Teil der diesjährigen Brut aus jungen Arbeiterinnen oder Geschlechtstieren. Die Arbeiterinnen des Vorjahrs sind wieder mager, da sie ihre Fettkörperreserven an die Larven verfüttert haben. Diese alten Arbeiterinnen beginnen dann, Nahrung zu sammeln, während die jungen Arbeiterinnen für das nächste Jahr gemästet werden. Die Lebensdauer einer Arbeiterin beträgt also ein oder zwei Jahre oder mehr. Die meisten Nester sind polygyn, alle Königinnen sind fertil, doch legen sie vermutlich unterschiedlich viele Eier. Die Koloniegründung erfolgt wahrscheinlich pleometrotisch. Die Nester befinden sich sehr tief im Boden, sie reichen bis zu einer Tiefe von 2.5 m bis 3.6 m. Die Kammern haben einen waagerechten Boden und eine leicht gewölbte Decke, sie sind durch einen einzigen senkrechten Gang miteinander verbunden. Die Gesamtfläche der Kammern ist mit der Arbeiterinnenzahl korreliert. Die Nester werden vergrößert, indem sowohl neue Kammern gebaut als auch vorhandene Kammern erweitert werden. Wenn Kammern vergrößert werden, dann wird die ursprüngliche Kreisform pseudopodienartig ausgelappt. Es wurden keine Kammern in einer geringeren Tiefe als 60 cm gefunden, die meisten Kammern befanden sich in der unteren Hälfte dieser tiefen Nester, wodurch im größten Teil der Nester das ganze Jahr über eine Temperatur zwischen 16° und 24° C herrscht. Die 9 ausgegrabenen Nester enthielten zwischen 560 und über 10.000 Arbeiterinnen. Mit drei voneinander unabhängigen Bestimmungen der jährlichen Zunahme der Arbeiterinnenzahl wurde das Alter des größten Kolonie auf 7 bis 9 Jahre geschätzt. Die Arbeiterinnen waren in den Nestern spezifisch verteilt. Junge, gemästete Arbeiterinnen wurden in den tieferen Kammern gefunden, während sich die Arbeiterinnen des Vorjahrs, die jetzt Sammlerinnen waren, häufiger in der Nähe der Oberfläche aufhielten. Es wird diskutiert, daß die Lebensweise dieser kryophilen Ameise und speziell das Nahrungssammeln während der kalten Jahreszeit die Konkurrenz mit anderen Ameisen mindert.
    Notes: Summary In north Florida (USA), foraging and above-ground activity of the antPrenolepis imparis Say begins in November and ends in March or early April when the workers seal the nest until the following November. During this winter foraging period, workers' gasters become enormously corpulent through deposition of fat, doubling to tripling worker lean weight. The colony remains reproductively inactive until late August or early September when the queen's ovaries develop and she lays eggs. The single pulse of brood is probably reared on material derived from the corpulent workers. When the workers reopen the nests in November, most of the brood are callow workers or sexuals and all of the previous year's workers are again lean, their nutrient stores having been converted to new workers. The old workers become foragers while the callows become corpulent for the next year. Workers thus live between 1 and 2 (or more) years. Most nests are polygynous, and all queens contribute to the egg pool, though probably not equally. The nests are 2.5 to 3.6 meters deep and consist of horizontal-floored, slightly domed chambers connected by a single vertical tunnel. As the worker population grows, total chamber floor area is increased by adding more chambers and by enlarging chambers, changing their shape from simple, nearly circular to lobed, ‘pseudopodial’ shapes. No chambers were found less than 60 cm below the ground surface, and most were in the bottom half of these deep nests, keeping most of the nest between 16 and 24° C, year-round. Among the 9 colonies sampled, the number of workers varied from 560 to over 10,000. An incipient colony contained 33 nanitic workers and a single queen. Using the annual increase in worker population, the largest colonies were estimated to be 7 to 9 years old. Young, replete workers were found in the deeper chambers, while the previous years' workers (now foragers) were more abundant near the surface. The peculiar life cycle of this winter-active ant is discussed as an avoidance of competition with other ants by foraging during the cold season.
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    Insectes sociaux 32 (1985), S. 321-324 
    ISSN: 1420-9098
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    Topics: Biology
    Description / Table of Contents: Resume Teleutomyrmex schneideri, Anergates atratulus, Epimyrma stumperi etLeptothorax goesswaldi ont été trouvées aux alentours de Briançon, France. On indique les localités et donne quelques informations concernant la biologie de ces espèces. La nécessité d'une protection des habitats de ces fourmisrares est discutée.
    Notes: Summary Teleutomyrmex schneideri, Anergates atratulus, Epimyrma stumperi, andLeptothorax goesswaldi have been found in the surroundings of Briançon, France. The localities are indicated and some information on the biology of these species is provided. The need for protection of the habitats of these rare ants is discussed.
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    Insectes sociaux 32 (1985), S. 313-320 
    ISSN: 1420-9098
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    Topics: Biology
    Description / Table of Contents: Resume Les nids deCamponotus detritus sont des structures simples, creusées parmi les racines de la végétation pérenne des dunes du désert de Namibie. Ils comprennent une série de tunnels et de chambres de 100–400 mm de profondeur, souvent tapissés avec des détritus. On ne trouve pas de «chambre royale» ou de réserves de nourriture. Le couvain se trouvait d'un bout à l'autre du nid. Les températures des nids variaient considérablement. Les températures moyennes des nids étaient d'environ 32°C en été et 20–23°C en hiver. Le nombre d'ouvrières par nid variait de 218 à 16 000 avec une moyenne de 3 404±570. Chaque colonie comprenait un à quatre nids. Seulement un nid par colonie avait des reines. Le développement des colonies et le changement de localisation des nids avaient lieu fréquemment.
    Notes: Summary Camponotus detritus nests are simple structures excavated among the roots of perennial vegetation in the sand dunes of the Namib Desert. They comprise a series of tunnels and chambers 100–400 mm deep, often lined with detritus. No “royal chamber” or food stores were found. Brood was found throughout the nest, throughout the year. Nest temperatures varied considerably. Mean nest temperatures were about 32°C in summer and 20–23°C in winter. The number of workers per nest varied from 218 to 16,000 with a mean and standard error of 3,404±570. Each colony comprised one to four nests. Only one nest per colony housed queens. Colony expansion and nest relocation occurred frequently.
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    Insectes sociaux 32 (1985), S. 329-330 
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    Insectes sociaux 32 (1985), S. 331-334 
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    Topics: Biology
    Description / Table of Contents: Zusammenfassung Dieser Bericht enthält grundlegende Daten zur Variationstreite der Form von Erdhügel bei zwei häufig verkommenden Termitenarten der westafrikanischer Savanne,T. geminatus undC. curtatus.
    Notes: Summary This paper reports basic data on the variation in mound shape of two common species of west african savanna termites,T. geminatus andC. curtatus.
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    ISSN: 1420-9098
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    Topics: Biology
    Description / Table of Contents: Summary We have studied the individual fecundity of queens belonging to a polygynous ant species reared in digynous conditions. Two major results appear: - the queen's individual fecundity, quantified during 5 weeks, is lower when queens are reared in digynous conditions than in monogynous conditions. The queens in digynous conditions put on less weight and the fecundity decreases. - when the two queens of an artificial digynous culture have the same physiological characters (equal weight), they lay the same number of eggs. So, inPlagiolepis pygmaea, there is neither functional monogyny nor physiological hierarchy. We could explain the decrease of the individual fecundity of the digynous queens by two hypothesis: the sharing of food between queens and the reciprocal production of queen pheromones. The acuteness of these two hypothesis inPlagiolepi is discussed.
    Notes: Resume Ce travail a pour but d'étudier la fécondité des reines d'une espèce polygyne dans un cas simplifié, celui de la digynie. Deux résultats apparaissent: - la fécondité individuelle des reines établie sur cinq semaines de ponte en condition de digynie est très diminuée par rapport à celle des reines élevées en condition monogyne. Cette baisse de fécondité est liée à une moins bonne prise de poids des reines en situation digyne; - lorsque deux reines en situation de digynie présentent au début de l'expérience des caractères physiologiques voisins (poids égal), elles émettent des quantités comparables d'œufs; il n'y a donc pas de monogynie fonctionnelle chezPlagiolepis pygmaea, ni de hiérarchie physiologique. Deux mécanismes pourraient expliquer la baisse de fécondité individuelle dans le cas de la digynie: le partage de la nourriture entre les reines et l'émission réciproque de substances phéromonales royales tendant à diminuer la ponte de l'autre reine. Leur efficacité dans le cas desPlagiolepis est discutée.
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    Description / Table of Contents: Resume Nous décrivons quantitativement l'organisation sociale chezAneuretus simoni avec un éthogramme social. La majorité des comportements des reines et des petites et grandes ouvrières est semblable à ceux des espèces de fourmis des sous-familles supérieures. L'analyse de Fagen-Goldman des fréquences des comportements montre que le répertoire observé était complet. Les tailles des répertoires étaient 5 comportements (reine), 14 comportements (grandes ouvrières), 28 comportements (petites ouvrières jeunes), et 31 comportements (petites ouvrières mûres). Ces tailles de répertoires sont comparables à celles d'autres espèces de fourmis. Les grandes ouvrières, dont on trouve seulement moins de deux en moyenne par colonie, ne montrent pas de comportements de soins envers les larves. Elles ne montrent pas de comportements défensifs. Les ouvrières jeunes montrent les comportements envers la reine, les larves, et aussi le comportement de récolte. Une comparaison de l'organisation sociale chezAneuretus simoni avec celle d'autres espèces primitives montre que le comportement social est semblable à celui des dolichodérines.
    Notes: Summary Social behavior inAneuretus simoni is quantitatively described in a social ethogram. The majority of acts exhibited by queens and minor and major workers are typical behaviors observed in species of the higher subfamilies of ants. A Fagen-Goldman analysis of the frequency of behavioral acts indicated that the observed repertory was complete. Observed repertory sizes were 5 acts (the queen), 14 acts (major workers), 28 acts (callow minor workers) and 31 acts (mature minor workers). These repertory sizes are comparable to those observed in other ant species. Major workers, which average less than two in number per colony, do not show brood care. Majors were also never observed to participate in colony defense. The behavioral repertory of callow minor workers includes queen-related acts, brood care, and foraging. A comparison of social organization inA. simoni and other so-called primitive and advanced species indicates that social behavior is very similar to that of dolichoderine species.
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    ISSN: 1420-9098
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    Topics: Biology
    Description / Table of Contents: Summary Foragers (huntresses) of the predaceous antSmithistruma truncatidens develop behaviorally from guard ants, which in turn originate from one or the other of two pathways: some serve first as nurses, others become directly guards. These stages behave differently towards the principal preys (Isotomid collembolans), as follows: flight or no reaction in young individuals; avoidance or backward movement in nurses; direct attack followed by stinging in guards; pause followed by approach and antennating, then seizure by appendage and stinging in huntress workers. Under experimental conditions, huntress workers acquire pausing behavior generally between the 16th and the 19th day after their first going outside the nest.
    Notes: Resume Une étude sur le polyéthisme montre que chezS. truncatidens les ouvrières pourvoyeuses sont issues des gardiennes ayant elles-mêmes une double ascendance. Une partie provient d'ouvrières inactives, l'autre, de nourrices. Lorsqu'on place des ouvrières des différents status sociaux en présence de proies essentielles (Collemboles Isotomidae) nous observons les réactions suivantes: fuite ou absence de réaction chez les néonates, évitement ou recul chez les nourrices, attaque directe et piqûre chez les gardiennes et immobilisations (arrêt) suivie d'une approche lente et d'une palpation antennaire bien marquée précédant la saisie d'un appendice et la piqûre chez les pourvoyeuses. L'acquisition de la phase d'arrêt chez les pourvoyeuses dans les conditions de nos expériences a lieu le plus souvent entre le 16e et le 19e jour suivant la première sortie.
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    ISSN: 1420-9098
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    Topics: Biology
    Description / Table of Contents: Summary Ants of the genusAphaenogaster (A. senilis, A. subterranea) do not engage in the usual exchange of foodstuff from mouth to mouth, but employ a complex method for provisioning of their colony. Workers carry to the nest various objects imbibed or coated with liquid sugar or body fluid from crushed insects. In the nest, other workers lick the food on the objects. The foragers are capable of placing these intermediary objects on the liquid food supply before carrying them away. They can thus be said to use them as “tools” in the conventional ethological acception.
    Notes: Resume Les fourmis du genreAphaenogaster, qui ne pratiquent pas le transfert de substances de bouche à bouche, utilisent une méthode complexe pour assurer l'approvisionnement de la société. Elles transportent jusqu'au nid des matériaux divers, imbibés ou enrobés de liquides sucrés ou de sucs animaux, qui sont ensuite léchés par les ouvrières restées dans le nid. Les récolteuses sont capables, avant ces prélèvements, d'apporter et de déposer des matériaux sur les sources de nourriture liquide offerte. Cette séquence de comportements peut être assimilée à l'emploi d'un «outil» au sens classique du terme en éthologie.
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    ISSN: 1420-9098
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    Description / Table of Contents: Summary The closure of ant societies was investigated in someLeptothorax species (mainlyL. lichtensteini) and inCamponotus lateralis ants, first by transferring individual workers to alien societies of the same species, and secondly by placing two societies of the same species together in an arena. Various behavioural modalities were observed. In theLeptothorax ants studied, the interactions occurring between a society and an intruder worker and those occurring during encounters among workers of two societies placed together in an arena showed on analysis that the behaviour of the workers in a society was highly variable and depended upon the intruding individual or society with which they were confronted. Wether a society will turn out to be open or closed depdends on the partners involved. Differences were observed according to whether the subjects wereLeptothorax ants belonging to the subgenusMyrafant (mainlyL. lichtensteini), orL. recedens ants belonging to the subgenusTemnothorax. On the other hand, no variability was observed amongC. lateralis ants subjected to the above experimental conditions, and the latter societies were found to be strictly closed.
    Notes: Resume Le processus de fermeture de la société est étudié chez quelquesLeptothorax (principalementL. lichtensteini), ainsi que chezCamponotus lateralis, en réalisant des transferts d'individus dans des sociétés étrangères, de même espèce, et en mettant en présence deux sociétés, également de même espèce, dans une arène. Différentes modalités comportementales apparaissent. Chez lesLeptothorax étudiés, l'analyse des interactions entre sociétés receveuse et ouvrière intruse d'une part, et entre les ouvrières lors de rencontres dans l'arène d'autre part, a permis de mettre en évidence une grande variabilité du comportement des ouvrières d'une société selon l'individu étranger ou la société mis en leur présence: en fonction du partenaire, une société peut se montrer ouverte ou fermée. Des différences apparaissent d'autre part selon qu'il s'agit deLeptothorax appartenant au sous-genreMyrafant (en particulierL. lichtenstein) ou de l'espèceL. recedens du sous genreTemnothorax. Au contraire, chezC. lateralis, dans les mêmes conditions expérimentales, on n'observe pas de variabilité des interactions; les sociétés se montrent rigoureusement fermées.
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    Insectes sociaux 32 (1985), S. 435-444 
    ISSN: 1420-9098
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    Topics: Biology
    Description / Table of Contents: Summary Bees visiting an artificial food source were observed in order to determine the frequency of occurrence of antenna-grooming movements as a function of the concentration of the sugar solution. Sojourns at the source during which no antenna grooming occurred were more frequent when the concentration was low or high than when it was intermediate; when antenna-grooming is performed during a sojourn, the number of such movements increases with rising concentration (fig. 1). The combination of antenna-grooming with other movements also depends on concentration. As concentration increases, so does the frequency of multiple consecutive antenna-grooming movements as well as the frequency of grooming movements separated by operation of the proboscis (fig. 2a, b). Antenna-groming movements between which other parts of the body are groomed occur most often with a 15% solution (fig. 2c); the combination in which the bee uses its proboscisand grooms other body parts between two antenna-grooming movements is most common with a 32% solution (fig. 2d). As concentration increases, the proportion of antenna-grooming movements carried out during sucking rises (fig. 3 above). As concentration decreases, the instances of unilateral antenna-grooming movements account for a larger proportion of all antenna grooming (fig. 3 below). The number of interruptions of sucking at the end of the sojourn is maximal at intermediate concentrations (fig. 4). The results are interpreted as follows. The central controller for antenna-grooming movements interacts with the controllers responsable for the other grooming movements. It is also influenced by the controllers for sucking. The interpretation of the genesis of antenna-grooming movements is an extended application of the disinhibition hypothesis for displacement activities.
    Notes: Zusammenfassung An einer künstlichen Futterquelle wurde die Häufigkeit des Auftretens von Fühlerputzbewegungen in Abhängigkeit von der Konzentration der Zuckerlösung untersucht. Bei niedrigen und hohen Konzentrationen sind Aufenthalte ohne Fühlerputzbewegungen häufiger als bei mittleren; wenn während eines Aufenthals Fühlerputzbewegungen auftreten, nimmt deren Anzahl mit steigender Konzentration zu (Abb. 1). Die Häufigkeit unmittelbar aufeinanderfolgender Fühlerputzbewegungen steigt mit zunehmender Konzentration; dasselbe gilt für Fühlerputzbewegungen, zwischen denen der Rüssel betätigt wird (Abb. 2a und b). Fühlerputzbewegungen, zwischen denen andere Körperteile geputzt werden, treten am häufigsten bei einer 15% igen Lösung auf (Abb. 2c); betätigt die Biene zwischen zwei Fühlerputzbewegungen den Rüssel und putzt andere Körperteile, liegt das Maximum der Häufigkeit bei einer 32% igen Lösung (Abb. 2d). Mit zunehmender Konzentration wächst der Anteil während des Saugens ausgeführter Fühlerputzbewegungen (Abb. 3 oben). Mit abnehmender Konzentration wächst der Anteileinseitiger Fühlerputzbewegungen am gesamten Fühlerputzen (Abb. 3 unten). Die Anzahl der Saugunterbrechungen am Ende des Aufenthalts weist ein Maximum bei mittleren Konzentrationen auf (Abb. 4). Die Ergebnisse werden folgendermaßen gedeutet: Zwischen der zentralnervösen Instanz, welche die Fühlerputzbewegungen steuert und den Instanzen, welche für die übrigen Putzbewegungen verantwortlich sind, finden Wechselwirkungen statt. Außerdem wird diese Instanz von der für das Saugen zuständigen beeinflußt. Die Deutung für das Zustandekommen der Fühlerputzbewegungen ist eine erweiterte Anwendung der Enthemmungshypothese für Uebersprunghandlungen.
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    Insectes sociaux 33 (1986), S. 45-58 
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    Description / Table of Contents: Zusammenfassung Wir berichten hier die Ergebnisse unserer Studien anPrionopelta amabilis, die erste genauere Untersuchung dieser pantropischen Gattung mit den kleinsten Arbeiterinnen in dem sehr primitiven Tribus Amblyoponini. 1. P. amabilis Kolonien wurden in verfaulenden Holzstämmen und Baumästen am Boden des Regenwaldes von Costa Rica gefunden. Zwei Kolonien, die sehr sorgfältig aus dem Holz abgesammelt wurden, enthielten eine Königin und eine für den Tribus Amblyoponini ungewöhnlich grosse Population von Arbeiterinnen. Eine Kolonie, die auch jungfräuliche Weibchen enthielt, hatte über 700 Arbeiterinnen. 2. P. amabilis erbeutet bevorzugt Dipluren, sie nehmen aber auch einige andere Arthropoden als Beutetiere an. Die Beute wird direkt an die Larven verfüttert. Die Königin erhält trophische Eier, die offensichtlich von den Arbeiterinnen gelegt werden. 3. Eine schwache, doch deutlich erkennbare, Arbeitsteilung zwischen verschiedenen Altersklassen existiert. Damit unterscheidet sichP. amabilis vonAmblyopone pallipes, die enzige andere Amblyoponine, die in dieser Hinsicht untersucht wurde. Jüngere Arbeiterinnen pflegen Brut und Königin. Aeltere Arbeiterinnen sind vorwiegend Futtersammler. Wie zu erwarten sind die Ovarien der Arbeiterinnen, die die Königin pflegen besser entwickelt, als die der Furagierameisen. 4. Soziales Trageverhalten unter adulten Ameisen konnte nicht beobachtet werden. Während Nestemigrationen wird nur die Brut transportiert. Ein merkwürdiges Schleifen der Hintertarsen bei einzelnen Arbeiterinnen könnte dem Spurenlegen oder der Substratmarkierung dienen. 5. Die Nestkammern, in denen Puppen gehalten werden, sind häufig mit alten Puppenkokonteilchen tapeziert. Das dient offensichtlich dazu, die Puppenkammern trockener zu halten.
    Notes: Summary We report here the first detailed account of a member ofPrionopelta, a pantropical genus possessing the smallest workers in the primitive ant tribe Amblyoponini. 1. Colonies ofP. amabilis were found nesting in small rotting logs and tree branches on the floor of primary rain forest in Costa Rica. Two that were more carefully excavated possessed a single dealate queen and a worker population unusually large for Amblyoponini. One of the latter colonies, which was in the process of eclosing alate queens (during late March), contained over 700 workers. 2. P. amabilis workers prey preferentially on campodeid diplurans, although they also accept (less readily) a limited variety of other small arthropods. The prey are given directly to the larger larvae. The queen is fed trophic eggs which we infer to have been laid by the workers. 3. A moderately well-marked temporal division of labor occurs, thus distinguishingP. amabilis fromAmblyopone pallipes, the only other amblyoponine hitherto studied in this regard. Younger workers attend the brood and queen, forming a retinue around the latter individual. Older workers are more active in foraging. As expected, the ovaries are better developed in workers associated with the queen than in foragers. 4. Emigration to nest sites is conducted individually, with the workers carrying brood but not other adult nestmates. A foot-dragging behavior, possibly associated with trail-laying, is described. Alarm pheromones are apparently absent. 5. A unique “wall-papering” behavior was also discovered: the workers line the pupal chambers with fragments of discarded pupal cocoons, rendering these spaces drier and hence presumably more suitable for pupal occupation.
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    Insectes sociaux 33 (1986), S. 59-69 
    ISSN: 1420-9098
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    Topics: Biology
    Description / Table of Contents: Zusammenfassung Erebomyrma, eine neotropische Gattung des Tribus Pheidologetini, hat nicht nur einen mitPheidole konvergenten Kastendimorphismus, sondern gleichtPheidole auch in der Form der Arbeitsteilung. Die Soldaten (major Kaste) vonE. nevermanni, helfen bei der Ueberwältigung von Beute, verteidigen das Nest, und dienen als Speichertier für flüssige Nahrung. Bei Anwesenheit der minor Arbeiterinnen haben sie ein begrenztes und spezialisiertes Verhaltensrepertoire, das jedoch erweitert wird (einschliesslich Nahrungssammeln und Brutpflege), wenn die minor Arbeiterinnen entfernt werden. Gleichlaufend mit dieser Bereicherung des Verhaltensrepertoires erfolgt eine etwa zehnfache Zunahme der allgemeinen Aktivität. Weitere Einzelheiten zur Biologie und zum Sozialverhalten vonE. nevermanni werden berichtet. Am bemerkenswertesten ist das »Verteidigungs-Gefolge« um die Königin, das verstärkt wird, wenn die Kolonie offen gelegt wird; die Nutzung von Sammelstrassen; das Erbeuten von Arthropoden-Eiern; und das Fehlen von sozialem Trageverhalten unter adulten Ameisen bei Kolonieemigration.
    Notes: Summary Erebomyrma, a Neotropical genus of pheidologetine ants with caste dimorphism convergent to that ofPheidole, also resemblesPheidole in its pattern of division of labor. The major workers ofE. nevermanni, the species examined during this study, assist in subduing larger prey, defend the nest, and serve as semi-repletes in liquid food storage. Their repertory is limited and specialized when minor workers are present but expands to include foraging and brood care when the minor workers are removed. The expansion is accompanied by a 10X or more increase in general activity rate. Other details of the natural history and social behavior ofE. nevermanni are given. The most distinctive properties include the occurence of defensive retinues around the queen which intensify when the colony is exposed, the use of trunk trails during foraging, predation on arthropod eggs, and the absence of adult transport during colony emigration.
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    Insectes sociaux 33 (1986), S. 85-99 
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    Description / Table of Contents: Zusammenfassung Freiland- und Laboratoriumsuntersuchungen einer Kolonie vonMyrmoteras toro, die im Central Sulawesi gesammelt wurde, und einerM. barbouri Kolonie von Singapore, lieferten die ersten ökologischen und verhaltensbiologischen Informationen über diese wenig bekannte Gattung der Unterfamilie Formicinae. Die Arbeiter jagen einzeln und fangen mit ihren langen Schnapp-Kiefern kleine weiche Evertebraten, ähnlich wie es von Arten der Dacetini und Odontomachini bekannt ist. Bevor die Jägerinnen zuschnappen öffnen sie Kiefer um 280°. Das ist der grösste Mandibel-Offnungswinkel, der bisher von Ameisen bekannt ist. Bei der Nestverteidigung werden Eindringlinge häufig mit den Mandibeln gestossen. M. toro jagt kleine, weiche Arthropoden, währendM. barbouri nahezu ausschliesslich Springschänze fängt. Ich nehme an, dass die Trigger-Haare, die typisch fürM. barbouri und andere Arten der UntergattungMyrmoteras sind, eine spezielle Anpassung für das Collembolenjagen sind. Rekrutierung zu Futter und Nestplätzen scheint nicht vorzukommen.
    Notes: Summary Field and laboratory studies on a colony ofMyrmoteras toro collected in Central Sulawesi and aM. barbouri colony from Singapore have provided the first ecological and behavioral information on this enigmatic formicine genus. Both species capture prey singly by the trap-jaw method, much as do many dacetine and odontomachine ants. Before striking the ants open their jaws 280°, the greatest degree yet recorded in the ants. Also, the nest area is defended from encroachment by other invertebrates by slapping intruders repeatedly with the mandibles. M. toro workers catch a variety of small, soft-bodied arthropods.M. barbouri preys largely or entirely on springtails. I hypothesize that the trigger hairs characteristic ofM. barbouri and other species of the subgenusMyrmoteras could represent an adaptation to collembolan prey. Recruitment to food (sugar baits) and during emigrations appears to be absent.
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    Insectes sociaux 33 (1986), S. 101-102 
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    Description / Table of Contents: Summary The role of antennal contacts made by the donor worker on the receiver's head during trophallactic interactions among Ants (Camponotus vagus) was investigated by studying the food flow characteristics: amount of foodstuff transmitted, duration and speed of transmission. For this purpose, we either removed both the donors' antennal funicles or tied their scape/funicule articulations in the flexed position. The parameters of food transmission between control workers were found to depend on seasonal factors: the consequences of both antennal removal and immobilization were therefore analysed for each season separately. The workers with antennal lesions gave more food than control workers in spring and summer. On the contrary, in autumn the lesions did not bring about any significant change. The antennal contacts made by the donor on the receiver's head might be involved in the regulation of trophallactic food transmission, at least in spring and summer.
    Notes: Resume Nous avons recherché quel est, lors des interactions trophallactiques entre ouvrières de Fourmi (Camponotus vagus), le rôle des contacts antennaires effectués par l'ouvrière donneuse sur la tête de la receveuse, quant aux caractéristiques du flux: quantité de nourriture transmise, durée, vitesse de transmission. Dans ce but, nous avons pratiqué soit l'ablation des funicules antennaires de la donneuse, soit l'immobilisation, en position pliée, des articulations scape/funicule. Chez les témoins, les caractéristiques du flux trophallactique varient avec la saison. Il en est de même pour les effets de l'ablation ou de l'immobilisation, qui ont donc été étudiés séparément pour chaque saison. Au printemps et en été, les ouvrières opérées donnent plus de nourriture que les ouvrières intactes. En automne, au contraire, l'opération n'entraîne pas de modification significative. Il apparaît que, du moins au printemps et en été, les contacts des antennes de l'ouvrière donneuse peuvent intervenir dans la régulation du flux trophallactique.
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    Insectes sociaux 33 (1986), S. 105-117 
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    Description / Table of Contents: Zusammenfassung Die zwei untersuchtenPseudomyrmex-Arten haben die folgenden Kommunikationssysteme: a) P. triplarinus informiert ihre Nestgenossinnen über das Vorhandensein von Futter, aber nicht über dessen Lage.P. termitarius hat keinerlei Kommunikation bei der Futtersuche. b) Beide Arten erkennen ihr Territorium anhand von Duftstoffen.P. triplarinus markiert ihr Territorium mit einem Pheromon aus dem Thorax, wahrscheinlich von der Metathorakaldrüse. Die territoriale Markierung hat eine Lebensdauer von einer halben bis einer Stunde. Sie dient wahrscheinlich der Verteidigung des Territoriums. Die Markierung vonP. termitarius hält über 5 Stunden an und wirkt wahrscheinlich als Nesteingangs-Orientierungsmarke. Die Herkunft des Duftstoffes ist nicht klar. c) P. triplarinus benützt ein Pheromon aus dem Kopf als Signal für das Erkennen ihrer Schwestern.P. termitarius verwendet nicht-identifizierte Duftstoffe, die überall im Körper vorhanden sind, als Identifikationssignal. d) Beide Arten haben Alarmpheromone im Kopf und im Abdomen. Die Kommunikationssysteme werden im Zusammenhang mit der oekologischen Adaption der Arten analysiert.
    Notes: Summary The twoPseudomyrmex species studied have the following communication systems: a) P. triplarinus informs its nestmates about the presence of food, but not about its location.P. termitarius does neither. b) Both species recognize their territory and/or area around the nest entrance through odours on the substrate.P. triplarinus marks its territory with a pheromone from the thorax, probably from the metapleural gland. This territorial mark lasts less than 1 h, and probably advertises at least part of the home range of the colony. The territorial odour used byP. termitarius, probably works as a nest entrance orientation mark, and lasts over 5 h, but less than 24 h. The origin of the odour is not clear. c) P. triplarinus uses a cephalic pheromone as the main signal for nestmate recognition.P. termitarius uses non-identified odours, present on all body parts of the insect, as a nestmate recognition signal. d) Both species produce alarm pheromones from the head and the gaster. The communication systems are interpreted in relation to the ecological adaptations of each species.
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    Description / Table of Contents: Summary Colonies ofMessor barbarus are monogynous and closed. Tests on societies during foundation showed that their closure is not complete. As long as the gyne is alone, she attacks and kills any stranger. When she has eggs and larvae, she accepts foreign eggs and larvae. With young workers, she may accept foreign workers and tolerate another gyne. It is possible to form a colony with two queens by joining two young societies. Older workers become aggressive and attack foreign conspecific ants: the societies are then permanently closed. Explanations of these changes in aggression are discussed.
    Notes: Resume Les sociétés deMessor barbarus apparaissent monogynes et fermées. Des expériences sur des sociétés en cours de fondation ont montré que leur fermeture n'est pas totale. Tant que la femelle fondatrice est seule, elle attaque et tue tous les individus étrangers. Son agressivité diminue quand elle possède du couvain. Peu après la naissance des premières ouvrières, les individus étrangers sont adoptés et il est même possible d'obtenir des sociétés définitivement digynes en réunissant deux jeunes sociétés. Au bout de quelques semaines naissent des ouvrières agressives vis-à-vis des étrangers et les sociétés sont alors définitivement fermées. Des explications à ces changements de l'agressivité sont proposées et discutées.
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    Insectes sociaux 35 (1988), S. 153-166 
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    Description / Table of Contents: Resume On a déjà montré (Brian, 1986b) que la sociabilité des reines deMyrmica rubra L. variait de l'état solitaire à très sociable. On rapporte ici que dans la colonie, les reines sociables se trouvent à proximité des œufs. Ces reines sont, au moins dans leur seconde année, plus lourdes car leurs ovaires et les tissus adipeux sont plus développés et leur fécondité est supérieure à celle des reines solitaires. Les reines solitaires vivent à la périphérie de la colonie et sont plus légères; leurs ovaires sont plus petits soit parce qu'ils se sont moins développés, soit parce qu'ils ont dégénéré. La fécondité est faible. Il s'agit de jeunes reines, de reines très âgées ou parfois de reines blessées. Les populations d'ouvrières varient en fonction du degré avec lequel elles régulent la répartition des reines; celles qui empêchent leur regroupement diminuent également la fécondité. Ainsi l'aversion mutuelle des reines et la régulation de la caste par les ouvrières limitent le nombre des reines présentes au cœur de la société. Seules les reines en pleine maturité qui peuvent pondre des œufs bipotentiels et ainsi contribuer au développement de la colonie peuvent fréquenter le cœur du nid.
    Notes: Summary Queens ofMyrmica rubra L. living in natural groups of workers, have been shown to range from sociable to solitary (Brian, 1986b). More data are now presented to show that the sociable queens tend to inhabit the core near the eggs, to be heavier as a result of having a well developed ovary and fat-body, to be at least in their second year of age and to lay more eggs. The solitary queens live peripherally and are lighter, have shorter ovaries that are either undeveloped or degenerate and only lay a few eggs. They are a mixture of first-year queens, spent queens or infirm ones. Worker populations vary in the degree to which they regulate the dispersion of queens; those which oppose central clustering also reduce fecundity. Thus both the queens by their mutual aversion and the workers by their grading of queens restrict entry into the nest core. Only the mature queens that can lay sex-competent eggs and so contribute to the full development of the society are able to frequent the core.
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    Description / Table of Contents: Zusammenfassung Der Lebensraum und die Nestbiologie der Afrikanischen Honigbiene,Apis mellifera scutellata, wurden an Völkern im natürlichen Verbreitungsgebiet im Delta des Okavango Flusses, Botswana, untersucht. Beobachtungen der Vegetation zeigten, daß den Völkern im Delta das ganze Jahr über reichlich Nahrung zur Verfügung steht. Die Koloniedichte betrug 7.8 Nester/km2. Nesthöhlen fanden sich gleich häufig in Bäumen wie in Termitenhügeln, sie hatten ein Volumen von ca. 17 L, waren nicht propolisiert und hatten nach Süden gerichtete, oben liegende Eingänge. Die Völker im Delta waren klein (ca. 6,500 Arbeiterinnen), sie bauten wenig Waben (ca. 3,000 cm2), speicherten wenig Nahrung, verwendeten 78% der Waben für die Brut und sie verfteidigten ihr Nest nur schwach; die Verlustrate durch Räuber betrug 48%. Die charakteristischen Eigenschaften, die fürscutellata in dieser Untersuchung beobachtet wurden, werden als Anpassungen an das heisse Klima, an die lange Trachtperiode und an die im Delta auftretende hohe Verlustrate diskutiert. Die Ergebnisse, die an Völkern im Delta gewonnen wurden, werden verglichen mit Ergebnissen anscutellata in anderen tropischen Gebieten und mit Ergebnissen anscutellata in anderen tropischen Gebieten und mit Ergebnissen an Honigbienen in gemäßigten Klimazonen.
    Notes: Summary The habitat and nesting biology were studied for naturally occurring colonies of the African honey bee,Apis mellifera scutellata, in the Okavango River Delta, Botswana. Vegetational surveys revealed that the forage available to Delta colonies was abundant and potentially available year round. Colonies had a density of 7.8 nests/km2. Nest cavities occurred with equal frequency in trees and termite mounds, had a volume of approximately 17 L, were unpropolized, and had south-facing, top-located entrances. Delta colonies were small (ca. 6,500 workers), constructed small amounts of comb (ca. 3,000 cm2), stored little food, devoted 78% of comb space to brood production, exhibited little nest defense, and experienced a 48% predation rate during the 5 month study period. The characteristics observed forscutellata in this study are discussed as adaptations to the hot climate, long foraging season, and high predation rate experienced in the Delta. Data for the Delta colonies are compared to those forscutellata in other tropical areas, and to honey bees in temperate climate regions.
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    Insectes sociaux 35 (1988), S. 209-213 
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    Description / Table of Contents: Zusammenfassung Arbeiterinnen vonCamponotus spp., die in weisellosen Gruppen aufgezogen wurden, erkennen nestfremde Verwandte anscheinend auf grund von genetisch bedingten chemischen Abzeichen oder “Diskriminatoren”, während Arbeiterinnen, die in Gegenwart einer Königen gehalten werden, von der Königin Abzeichen annehmen, die ein solches Verwandtenerkennen verhindern. Wir untersuchten, inwieweit diese von der Königin stammenden Abzeichen ebenfalls genetisch bedingte chemische Marken darstellen. Dazu wurdenC. floridanus Arbeitergruppen, bestehend aus genetischen Geschwistern, oder nicht verwandten Tieren, in Gegenwart jeweils einer nicht begatteten Königin aufgezogen. Die Königinnen waren entweder Schwestern oder stammten aus verschiedenen, weit entfernten Nestern. In neutralen Arenatests wurde geprüft, inwieweit sich Angehörige verschiedener Adoptionsgruppen als Geschwister erkennen können. Dabei zeigte sich, dass Arbeiterinnen aus Gruppen, deren Adoptions-Königinnen Schwestern waren, sich weniger aggressiv zueinander verhielten, als Arbeiterinnen deren Adoptions-Königinnen aus verschiedenen Nestern stammten. Das legt den Schluss nahe, dass die von Königinnen übertragenen Abzeichen echte Diskriminatoren darstellen.
    Notes: Summary Camponotus spp. workers reared in queenless groups recognize non-nestmate kin, apparently by shared heritable chemical cues or “discriminators”, while workers reared in the presence of mated queens acquire labels which superoede such recognition. Whether queen-derived labels are themselves discriminators has not been examined previously. Groups of sister or unrelated workers ofC. floridanus were adopted to sister or unrelated virgin queens, and recognition among non-nestmate adoptees was assayed in neutral arena encounters. Interactions were significantly less aggressive among workers whose queens were sisters than among those whose queens were not, indicating that their acquired recognition cues are queen discriminators.
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    Insectes sociaux 35 (1988), S. 206-208 
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    Description / Table of Contents: Resume On décrit un système économique, léger et stable pour héberger temporairement et pour expédier des colonies de fourmis vivantes, ou d'autres petits insectes (fig. 1). Seulement deux types de tubes transparents et flexibles de PVC, des bouchons de PVC et un morceau de gaze de cuivre sont nécessaires pour faire le système. Les insectes sont aspirés dans les tubes.
    Notes: Summary A cheap, light and stable system for temporary housing and mailing live ant colonies, or other small insects, is described (fig. 1). Only two sizes of transparent and flexible PVC-tube, PVC-stoppers and a piece of copper gauze are needed to make the system. The insects are aspirated into the tubes.
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    Description / Table of Contents: Zusammenfassung Für die subtropische Polistine WespeRopalidia fasciata, die neue Nester unabhängig gründet, werden das Wachstum neugegründeter Kolonien sowie deren Überlebensrate beschrieben. Wird ein Nest von mehreren Weibchen gemeinsam gegründet, so stammen diese Weibchen vom selben Elternnest. Die Wachstumsrate neugegründeter Nester in Zellen/Tag (entspricht etwa der Eilegerate) hängt sowohl von dem Entwicklungsstadium der Kolonie wie auch von der Anzahl der Weibchen ab. Die Nestentwicklung (Zellen/Tag) ist positiv mit der Anzahl der Weibchen korreliert. Die Nestgröße nimmt im ersten Stadium, in dem nur Eier vorhanden sind, schneller zu als in dem folgenden Stadium, in dem auch Larven vorhanden sind. Die ersten Arbeiterinnen haben eine kürzere Entwicklungszeit als die später aufgezogenen Arbeiterinnen. Dieser Unterschied dürfte mit der intensiven Brutpflege der Weibchen für die ersten Larven zusammenhängen. Neugegründete Kolonien gehen vor allem durch äußere Ursachen zugrunde: (1) Durch den Verlust der Nestgründerinnen in solchen Kolonien, die von einem Weibchen allein gegründet wurden; (2) durch große Räuber, die auch Kolonien mit mehreren Nestgründerinnen vernichten.
    Notes: Summary Growth of preemergence colonies and colony survivorship of an independent founding polistine wasp,Ropalidia fasciata, in the subtropics are described. When a nest is founded by an association of females, foundresses originate from the same natal nest. Growth rate of preemergence nests in cells/day (nearly equivalent to oviposition rate) is a function of both stage of preemergence colony development and number of foundresses. Rate of nest development (cells/day) is positively correlated with the number of attending foundresses. Nest size increases more rapidly in the egg stage than in the larval stage. The first worker(s) develops faster than does later brood. This may be attributed to the fact that foundresses provide the first larva(e) with intensive care. Factors causing the failure of preemergence colonies are extrinsic: (1) the loss of the foundresses in single-foundress colonies, and (2) predation by large predators on colonies with multiple foundresses.
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    Insectes sociaux 36 (1989), S. 219-234 
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    Description / Table of Contents: Resume L'ovariectomie des fondatrices deP. gallicus permet de distinguer une dominance sociale d'une dominance de reproduction. Les fondatrices ovariectomisées peuvent acquérir un rang dominant et le conserver. Les caractéristiques de la dominance sociale (temps passé au nid, faible récolte de nourriture, comportement de dominance) ne sont pas liées a la présence des ovaires. Par contre, les ovariectomisées ne manifestent pas de dominance de reproduction. Elles n'inhibent pas la formation des œufs des subordonnées avec la même intensité que les dominantes intactes; elles ne pratiquent pas d'oophagie différentielle. Ces deux caractères impliquent la présence d'ovaires actifs.
    Notes: Summary By means of ovariectomy it was possible to separate social and reproductive dominance in foundresses ofP. gallicus. Ovariectomized foundresses could achieve and maintain the dominant position. Characteristics of social dominance (time on nest, low contribution to food collecting, dominance behaviour) were found not to be connected to the presence of ovaries. Reproductive dominance, however, did not occur in ovariectomized foundresses. Ovariectomized dominant females did not nihibit egg-formation in subordinates to the same degree as intact dominant females did and they did not show differential oophagy. For both characteristics the presence of active ovaries is necessary.
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    Insectes sociaux 36 (1989), S. 264-276 
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    Description / Table of Contents: Resume On examine différents facteurs qui pourraient affecter l'activité des glandes hypopharyngiennes (HP) des ouvrières d'Abeille, tels que l'âge des ouvrières, les stades de développement du couvain et le moment d'introduction ou de retrait du couvain. L'âge des abeilles exerce une influence marquée sur l'activité des glandes HP; celle-ci est corrélée avec la croissance et la résorption des glandes décrites dans la littérature. Seules les larves sont aptes à activer les glandes HP, alors que les œufs et les nymphes ne le sont pas. Les glandes de l'abeille restent inactives pendant trois jours après le début du nourrissage des larves; elles conservent leur activité pendant trois jours environ après le retrait des larves. Ces données sont en accord avec l'hypothèse que c'est le comportement de nourrissage lui-même qui active les glandes; cependant, on ne peut exclure la possibilité que les larves produisent une phéromone stimulante.
    Notes: Summary The effects of worker age, brood stage and time of brood introduction or brood withdrawal on the hypopharyngeal (HP) gland activity of worker bees were examined. Worker age exerted a marked influence on gland activity. Only larvae affected HP gland activity, while eggs and pupae did not. Bees had inactive glands until their third day of larval feeding and they maintained high gland activity for approximately three days after larval removal. The data are congruent with the hypothesis that feeding behaviour itself causes gland activation, although the possibility that larvae produce a primer pheromone cannot be excluded.
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    Insectes sociaux 36 (1989), S. 277-292 
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    Description / Table of Contents: Zusammenfassung Eine obligatorisch monogyne und eine fakultativ polygyne Form vonCamponotus nawai Ito wurden vergleichen. Jahreszeitliche Veränderungen der Koloniezusammensetzung waren bei beiden Formen ähnlich, abgesehen von der Zeit, in der geflügelte Geschlechtstiere in den Nestern zu finden sind. Die Sammelergebnisse lassen annehmen, daß bei der monogynen Form neue Kolonien nur von einzelnen Königinnen gegründet werden, während sie bei der polygynen Form durch Kolonieteilung entstehen. In polygynen Völkern waren alle oder fast alle Königinnen fertil, sa daß eine funktionelle Polygynie vorliegt. Königinnen der monogynen Form sind größer und haben größere Ovarien. Die Königinnen der polygynen Form zeigen eine bimodale Grossen-verteilung doch sind die kleineren Königinnen seltener. Bei der polygynen Form war die Anzahl der Königinnen mit der Menge der Brutstadien positiv korreliert, aber negativ mit der Menge der Brustadien pro Königin. Anscheinend besiedelt die polygyne Form mehr nördliche Gebiete als die monogyne, ihre Areale überschneiden sich kaum. Aufgrund der jahreszeitlich verschiedenen Schwarmzeiten sind die monogyne und die polygyne Form vonC. nawai möglicherweise zwei verschiedene Arten.
    Notes: Summary Obligately monogynous and facultatively polygynous forms ofCamponotus nawai Ito was compared. The seasonal changes of colony composition were similar in the two forms except for the season in which alates were found in nests. Collection data suggested that new colonies are founded only by single foundresses in the monogynous form, but mainly by colony budding in the polygynous form. All or most queens in polygynous nests were fertile, thus polygyny is functional. The body size and ovarian volume of queens were larger in the monogynous forms. Queens of the polygynous form showed bimodal size distribution, though smaller queens were less frequent. In the polygynous form, the number of queens was positively correlated with the number of immatures, but negatively correlated with the number of immatures per queen. It seems that the polygynous form occupies more northern regions than the monogynous one and their ranges contact parapatrically. The monogynous and polygynous forms ofC. nawai may be different species because of the differing mating seasons.
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    Insectes sociaux 35 (1988), S. 262-270 
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    Topics: Biology
    Description / Table of Contents: Zusammenfassung Mit zunehmendem Alter durchlaufen die Arbeiterinnen der Honigbiene in gesetzmässiger Reihenfolge ihre Tätigkeiten: sie gehen von der Brutpflege zum Bauen, dann zur Sammeltätigkeit über. Wenn man den Arbeitsmarkt künstlich, aber nur mässig stört, dann passen sich die Bienen dadurch an, dass sie einige Tätigkeiten intensiver ausführen, ohne dass dabei aber das mittlere Alter für diese Tätigkeit geändert wird. Dies steht im Gegensatz zu anderen Untersuchungen, wo der Arbeitsmarkt drastisch gestört wurde, z. B. durch Entfernung der meisten oder aller alten oder jungen Arbeiterinnen. Durch solchen drastischen demographischen Stress wurde eine Umstellung in der Altersstufe für bestimmte Tätigkeiten erwirkt. Die in dieser Arbeit durchgeführten demographischen leichten Manipulationen lassen den Schluss zu, dass der Bienenstaat bei verschiedenen Anforderungen an den Arbeitsmarkt durchaus plastisch beweglich ist, aber nicht maximal sich umstellen kann.
    Notes: Summary Worker honey bees proceed through a sequence of tasks, passing from hive and guard duties to foraging activities. When presented with moderate demographic alterations in colony age structure, bees may work harder at some tasks but do not significantly alter median ages of task performance for many behaviour patterns. This is in contrast to other studies that have presented colonies with more drastic demographic stresses (i.e., removal of most or all old and/or young workers) and which have demonstrated dramatic changes in the ages of task performances. The additional efforts invoked by demographic manipulations are consistent with a viewpoint that considers honey bee colonies to be resilient rather than maximally efficient systems.
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  • 43
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    Insectes sociaux 32 (1985), S. 61-69 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Von der anliegenden Erdhügeln den 5 weitverteilenden Termitengattungen, die an 2 Lagen nach dem Süd und Südwest von Townsville, nord Queensland, sind, sind die Verwandschaften untersucht worden. Es ist gezeigt worden, dass 4 diesen Gattungen, nämlichAmitermes laurensis (Mjöberg),Tumulitermes pastinator (Hill),Drepanotermes rubriceps (Froggatt) undDrepanotermes perniger (Froggatt) polycalisch sind, worin eine einzige Kolonie bis 8 Erdhügeln enthält. Eine enfache unzweideutgie Methode gebrauchte wurde. Ein Köder, der einen radioactiveren (131I) Indikator enthielt, in einem Erdhügel eingeführte wurde, dann wurde die nachfolgende durch Termiten nach anderen Erdhügeln Ubertragung diesem Köder mit einen Szintillationsdetektor kontrolliert. Die Darstellung der Erdhugelverteilungs — tatsachen verhandert ist dadurch, dass zwischen einigen australienischen Termitenkolonien gibt es die polycalischen Erdhügeln. Im einzelnen, kann die überzerstreuung der Erdhügeln für einigen gattungen als Indikation der innenspecifischen Mitbewerbung, nicht erklärte wird, wenn die Lagen der polycalischen Erdhügeln unbekannt wird.
    Notes: Summary The relationships of adjacent mounds of five widely distributed species of termites, at two sites south and southwest of Townsville in north Queensland have been examined. It has been shown that four of these species,Amitermes laurensis (Mjöberg),Tumulitermes pastinator (Hill),Drepanotermes rubriceps (Froggatt) andDrepanotermes perniger (Froggatt), are polycalic, with up to eight mounds comprising a single colony. A simple unequivocal method was used. A bait containing a radioactive tracer (131I) was introduced to a mound and the subsequent transfer of this bait to other mounds by termites was monitored with a scintillation detector. The existence of polycalic mounds among some Australian termite colonies alters the interpretation of mound distribution data. In particular, overdispersion of the mounds of some species cannot be interpreted as indicating intraspecific competition if the locations of polycalic mounds are unknown.
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  • 44
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    Insectes sociaux 32 (1985), S. 43-60 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Resume ChezParischnogaster nigricans serrei le nid est fondé par une seule guêpe. Quelquefois la fondatrice peut être flanquée, de temps en temps, d'autres femelles ou de mâles. La phase de nid initial commence par la première operculation. La fondatrice se repose sur les cellules operculées et réduit ses sorties. L'activité de construction du nid, de ponte, et le développement ovarien de la fondatrice subissent un fléchissement. La phase de colonie jeune est caractérisée par l'éclosion de femelles et par un rapide agrandissement du nid. La fondatrice se consacre aux activités sur le nid et ses ovaires grandissent. Dans la phase de colonie entre deux âges commence l'éclosion des mâles. Toutes les femelles sont fécondées entre le 20e et le 50e jour après l'éclosion et les femelles fécondées présentent des ovaires plus développés que les femelles non fécondées de même âge. Quelques femelles restent sur le nid comme femelles subordonnées ou de remplacement, tandis que d'autres fondent de nouveaux nids ou usurpent d'autres colonies. Dans les colonies mûres on trouve de nombreuses femelles pondeuses en puissance. Dans les colonies vieilles l'équilibre est très instable et la plupart des individus peut abandonner la colonie à la suite de perturbations d'origine interne ou externe. On revient ainsi à une phase précédente du cycle colonial.
    Notes: Summary InParischnogaster nigricans serrei nests are usually founded by single wasps. Old nests are often reused. Sometimes foundations can be joined by males or other females for brief periods. The initial nest phase begins with the closure of the first pupal cell. The foundress usually rests on the closed cell and reduces her journeys. Nest construction, egg laying and the ovarian development of the foundress undergo a reduction. The phase of the young colony is characterized by the emergence of females, rapid growth, specialization of the foundress in nest activities and the increase of her ovarian size. In the middle aged colony males begin to emerge. Females are all fertilized between 20 and 50 days from emergence; fertilized females have ovaries more developed than unfertilized ones of the same age. Some females remain on nests behaving as subordinate and substitution females, while others found new nests or usurp other colonies. In the mature colonies potential egg layers become frequent. In old colonies equilibrium seems to be very unstable and internal or external perturbations may cause the abandonment of the colony by most individuals and the return to a previous phase of the colony cycle.
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  • 45
    ISSN: 1420-9098
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    Topics: Biology
    Description / Table of Contents: Summary In the antCataglyphis cursor, the developement of alate forms in laboratory rearings occurs from late March to late June and needs adequate conditions of temperature and food. The queen inhibits worker egg laying; she prevents other queens from developing in small incipient colonies. Several years of experiments show the following: 1- Larvae moved from a society producing only workers to another society made apart from the same colony having just overwintered and producing alates, can grow into queens. This “sexualization” succeeds for brood originating from queens as well as for brood issued by thelytoky from orphaned workers. 2- Conversely, large larvae (alate biased), except the ones which are close to pupation, die when put into homocolonial societies which have been active for two month after overwintering and therefore only able to produce workers. 3- The period of maximum efficiency for the production of alates by workers occurs between 10 and 20 days after the end of overwintering. 4- Female larvae can develop into queens or workers until the early third and last instar. 5- By increasing the nurse/larvae ratio, up to 100% of sexuals can be obtained. 6- Young workers, eclosed the year before, are able to sexualize the female larvae and rear male larvae to imagoes. After the winter diapause, the fat body of young nurses is abundant; they exhibit high physiological activity in ovarioles, corpora allata and postpharyngeal salivary glands. Older workers are still able to oviposit but unable to rear their own offspring. 7- Development and sexualization of larvae transferred to alien colonies is possible if all the recipient colony's eggs are removed and if the two colonies originate from geographically close localities. Adopted larvae are rapidly abandoned and die if the native brood is left in the nest; the latter normally develops into alates. 8- Similarly, male larvae need to be reared by young vernalized nurses to develop. Male larvae seem to be relatively susceptible and rare in the brood. They suffer heavy mortality while developing. The physiological condition of nurse-workers seems to be determinant for development and survival of sexuals. The role of thelytoky in the field and its implications for population structure and worker control of the colony are briefly discussed.
    Notes: Resume Chez la fourmiCataglyphis cursor, le développement des sexués ailés a lieu au printemps; il nécessite en élevage, une température et une nourriture suffisantes. La reine inhibe la ponte des ouvrières et empêche la formation d'autres reines dans les jeunes colonies où la population est encore faible. Des expériences renouvellées durant plusieurs années ont permi de mettre en évidence les points suivants: 1- Des larves à devenir ouvrières, transférées dans des sociétés homocoloniales sortant d'hivernage, peuvent évoluer en reines. Cette «sexualisation» réussit avec des larves issues du couvain pondu par une reine comme avec du couvain issu d'ouvrières, par parthénogenèse thélytoque. 2- Inversement, des grosses larves d'ailés (sauf si elles sont très proches de la nymphose) avortent lorsqu'elles sont données à des sociétés homocoloniales sorties depuis longtemps d'hivernage. 3- La période optimale pour l'élevage des ailés se situe entre 10 et 20 jours après la sortie d'hivernage. 4- Les larves femelles restent bi-potentielles reine/ouvrière jusqu'au début du 3e stade. 5- En diminuant le nombre des larves par rapport au nombre d'ouvrières éleveuses, on peut obtenir jusqu'à 100% de reines. 6- Le couvain est sexualisé par les jeunes ouvrières, nées l'année précédente; après la diapause hivernale, leur corps gras est abondant, les ovaires, les corps allates et les glandes postpharyngiennes montrent des signes d'activité élevée. Les ouvrières âgées de plus d'un an peuvent encore pondre mais semblent incapables d'élever des larves jusqu'au stade adulte. 7- La sexualisation des larves par des ouvrières étrangères reste possible si l'on retire tous les œufs pondus par les ouvrières-hôtes et si le transfert de larves est tenté entre colonies d'une même localité ou de localités géographiquement proches. Des larves adoptées, dont la sexualisation est en cours, avortent lorsque le couvain indigène est laissé en place; celui-ci évolue normalement en produisant des ailés. 8- Pour se développer, les larves de mâles ont aussi besoin d'être soignées et nourries par des ouvrières sorties d'hivernage depuis peu. Les larves de mâles paraissent relativement fragiles et subissent une forte mortalité au cours de leur développement. Le rôle de la parthénogenèse dans la nature et ses implications sur la structure des populations et le contrôle de la colonie par les ouvrières sont brièvement discutés.
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  • 46
    ISSN: 1420-9098
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    Topics: Biology
    Description / Table of Contents: Summary The life spans of femalesPolistes were influenced by the social environnement found at the emergence time, within the limits set by a probable larval predisposition. An early separation from the natal colony reduced the proportion of wasps able to overwinter and to found a nest the next spring. On the other hand, the removal of older larvae from the brood increased the proportion of long-lived wasps among the imago that undergo this situation. The functional consequences of these findings are discussed.
    Notes: Resume Cette étude montre que la durée de vie des femelles de poliste est influencée, dans les limites d'une probable prédisposition larvaire, par les conditions sociales rencontrées à l'émergence. La séparation précoce d'avec le guêpier d'origine diminue fortement la proportion des descendantes qui supportent l'hiver et fondent au printemps suivant. Par contre, la destruction, dans le couvain, des larves de grande taille provoque un accroissement de la proportion des descendantes à vie longue parmi les guêpes subissant cette situation à l'état imaginal. On discute la signification fonctionnelle de ces résultats.
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  • 47
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Resume Les ouvrières deLeptothorax unifasciatus utilisent des repères chimiques et des repères visuels au cours des activités de fourragement. Cependant, une orientation ménotactique (ampoule lumineuse de 60 watt) et reposant sur des repères visuels ambiants domient une orientation chimique. Un trajet effectué vers la nourriture suffit aux ouvrières pour s'orienter ensuite sur une ampoule lumineuse. Les ouvrières tracent une piste au cours du fourragement n'ayant pas fonction de recrutement, mais agissant comme repère orientationnel individuel. Ces pistes sont distinguées et préférées même lorsqu'elles sont superposées à plusieurs autres. Néanmoins, les ouvrières acceptent de suivre les pistes de leurs congénères en l'absence de leur propre piste. Les ouvrières nouvellement recrutées sont incapables de s'orienter sur les pistes chimiques.
    Notes: Summary Leptothorax unifasciatus workers use both chemical and visual cues when foraging. A visual orientation based on menotactical cues (60 watt light-bulb) and environmental cues (laboratory surroundings) dominate over a chemical orientation. The learning response to a 60 watt light-bulb cue occurs after a single trip to the food source. Workers lay down a trail when foraging which helps them to orient themselves but does not recruit other nestmates. Such trails are distinguished and preferred even when superposed by several other nestmates' trails. Nevertheless, the foragers are able to follow their nestmates' trails if their own is somehow missing. Newly recruited ants are unable to orient along chemical trails.
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  • 48
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    Topics: Biology
    Description / Table of Contents: Resume Les ouvrières deLeptothorax unifasciatus différencient de nouvelles aires de celles précédemment explorées. En effet, un comportement de «va-et-vient» apparaît plus fréquent sur un papier vierge que sur un papier familier à la colonie. La chute d'activité sur un papier vierge après quelques heures indique que ce dernier devient rapidement familier à la colonie dans le dispositif expérimental utilisé. Les expériences suggèrent que le territoire est modifié chimiquement par l'activité des fourmis, mais la possibilité d'un marquage chimique n'a toutefois pas été explorée. Trois facteurs contrôlent le niveau d'activité de fourragement chezL. unifasciatus: 1o la nature de l'aire de récolte (connue ou inconnue); 2o la taille de la société; 3o le temps de séjour de la société dans un même nid. Des sociétés établies récemment dans leur nid montrent un niveau d'activité de fourragement plus élevé sur une aire de récolte inconnue que sur une aire familière. Dans tous les cas, il existe une relation linéaire liant la taille de la société et son activité. Des sociétés établies depuis longtemps dans un même nid montrent toujours une activité inférieure aux sociétés récemment établies. Aucune différence n'est observée entre une aire de récolte inconnue et familière. De plus, la taille de la société apparaît être moins influente sur son activité générale que pour une société récemment établie dans son nid. Ces résultats sont interprétés en termes éco-éthologiques, tenant compte d'une caractéristique biologique essentielle des sociétés deL. unifasciatus: les déménagements fréquents, saisonniers ou liés à la précarité des nids.
    Notes: Summary Leptothorax unifasciatus workers differentiate new areas from those previously explored. Indeed, a “coming and going” behaviour appears more frequent on a virgin paper than on a familiar one. The decrease of activity on a new paper after some hours indicates that this species rapidly gets to known such an area in the experimental device used here. The experiments suggest that the area is chemically modified by the ants' activity, but the possibility of a specific marking behaviour was not further investigated. Three factors control the level of foraging activity inL. unifasciatus: 1o. The nature of the foraging area (familiar or virgin). 2o. The size of the society. 3o. The age of the nest-site. Societies newly established in their nest show a higher level of foraging activity on a virgin area than on a familiar one. In every case, there is a linear relation between the size of the society and its activity. Long-settled societies always show a lower activity than recently established ones, and no difference was observed when they recruited on a virgin and a familiar area. Moreover, the society size appears to be less important in determining the general level of activity than for recently-settled societies. These results are tentatively interpreted in eco-ethological terms, taking into account a main biological characteristic ofLeptothorax societies: frequent nest emigrations that are either seasonal or due to fragile nest-sites.
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  • 49
    ISSN: 1420-9098
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    Topics: Biology
    Description / Table of Contents: Resume Dans un article précédent nous avons étudié au laboratoire la production des diverses catégories de descendants durant la vie de la colonie. Nous étudions ici plus particulièrement la durée de vie propre de ces diverses catégories. La durée de vie des femelles montre une distribution bimodale et nous avons discerné des guêpes «à vie courte» et «à vie longue». Un chevauchement existe entre les phases de production de ces deux catégories. Il existe une relation entre la date de l'orphelinage, la proportion des femelles «à vie courte» et le sex ratio de la descendance. Les colonies précocement orphelines ont, en fait, une descendance totale accrue, mais cette descendance est surtout mâle et parmi les femelles produites, les guêpes «à vie courte» sont les plus nombreuses.
    Notes: Summary In a previous paper we described a study under laboratory conditions of the pattern of development of the various categories of descendants during the life of a colony; the present study is particularly concerned with the duration of life-span of these various categories. The life-spans of females showed a bimodal distribution and short-lived and long-lived wasps were distinguished. Considerable overlap was observed between the periods during which these two categories of wasp emerged. A relationship was found to exist between the date of orphanship, the percentage of “short-lived” females and the sex ratio of the offspring. Colonies which lost their queen as early as June showed an increase in the number of descendants produced, but these descendants were predominantly male and, among the females, the majority were “short-lived”.
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    Insectes sociaux 33 (1986), S. 388-405 
    ISSN: 1420-9098
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    Topics: Biology
    Description / Table of Contents: Summary The analysis of the possibilities of localization of prey by foraging workers shows that the maximal distance is 3 mm.eThe whole behaviour sequence includes the following phases: detection, localization, approach, antennation, attack with abrupt mandible closure, lifting, stinging and transport. A sequential analysis establishes that antennation is more emphasized when the prey is immobilized or is anaesthetized with CO2. In this last case, the prey is seized by a slow closure of the mandibles of the ant which is followed by transport to the nest. The lifting and stinging phases are more frequent when the living prey is larger. In this case, the attack is insufficient to kill or to knock out the prey which struggles to pull away. After a failure during an attempt of capture the ant presents a new behaviour allowing a quick localization of the prey.
    Notes: Resume L'analyse des possibilités de localisation des proies par les ouvrières pourvoyeuses montre que la distance maximale est de 3 mm. La séquence comportementale la plus riche, lors de la capture de la proie, comprend les phases suivantes: détection, localisation, approche, palpation antennaire, attaque avec fermeture brusque des mandibules, soulèvement, piqûre et transport. Une analyse séquentielle montre que la palpation est la plus intense quand la proie s'immobilise ou est anesthésiée au CO2. Dans ce dernier cas, la proie est saisie à la suite d'une fermeture lente des mandibules suivie aussitôt du transport vers le nid. Les phases de soulèvement et de piqûre sont d'autant plus fréquentes que la proie vivante est plus grosse. En effet, dans ce cas, l'impact de l'attaque est insuffisant pour tuer ou étourdir la proie qui se débat afin de se dégager. A la suite d'un échec au cours d'une tentative de capture, un comportement particulier permet aux fourmis de retrouver leur proie.
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  • 51
    ISSN: 1420-9098
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    Topics: Biology
    Description / Table of Contents: Resume Neuf colonies du termite inférieurIncisitermes schwarzi, résidant dans les longs et étroits troncs morts de manglier, ont été sectionnées sur le terrain; les découpes ont été reportées au laboratoire et dans chaque section les termites ont été classés selon leur sexe et leur caste. Dans une série distincte d'observations, des portions des colonies ont été introduites dans un étroit tunnel et ultérieurement la position, le sexe et la caste de chaque individu furent enregistrés. Les données résultant de ces deux études indiquent que les sexes sont répartis au hasard parmi la colonie de termites; aussi bien à l'intérieur des castes qu'entre différentes castes. La seule exception était la légère tendance des soldats d'un sexe donné à s'associer avec les individus du sexe opposé d'une autre caste. Les observations ne soutiennent pas la thèse selon laquelle la parenté génétique des individus du même sexe et de même parents (dû à la multiplicité des chromosomes sexuels) et la préférence sexuelle du comportement altruiste, in fluencent l'évolution de l'eusocialité des termites.
    Notes: Summary Nine colonies of the lower termiteIncisitermes schwarzi, inhabiting tall, narrow dead mangrove tree trunks, were sectioned in the field; the sections were taken back to the laboratory and the termites in each section were classified by sex and caste. In a separate series of observations, portions of colonies were introduced into a narrow tunnel, and later the position, sex, and caste of each individual were recorded. The data from both kinds of study indicate that the sexes are distributed randomly within the termite colony, both within castes and between castes. The only exception was a slight tendency for soldiers of one sex to be associated with non-soldiers of the opposite sex. The observations do not support the idea that the close genetic relatedness of same-sex siblings (due to multiple sex chromosomes) and preferential sex-biased altruistic behavior underly the evolution of eusociality in termites.
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  • 52
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    Pure and applied geophysics 123 (1985), S. 261-271 
    ISSN: 1420-9136
    Keywords: Tropical atmosphere ; Trade cumulus clouds ; Convective boundary layers
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    Topics: Geosciences , Physics
    Notes: Abstract It is suggested that the gross mean vertical structure of the undisturbed tropical atmosphere may be understood in terms of convective boundary layers driven in different ways and on different time scales by the evaporation of water from the sea surface. The mixed layer on a short time scale is driven partly by the buoyancy produced by the light weight of the water vapor; the trade cumulus layer on an intermediate time scale by the buoyancy (but not heating) produced by the condensation of the water vapor in shallow trade cumulus clouds; and the troposphere itself on a long time scale by the buoyancyand heating produced by the condensation of the water vapor in the deep cumulonimbus clouds.
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    Pure and applied geophysics 123 (1985), S. 293-304 
    ISSN: 1420-9136
    Keywords: Atmospheric tides ; Lunar effects ; Ocean-atmosphere interaction ; New Zealand
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The lunar barometric tide has been determined with reasonable accuracy, on an annual and seasonal basis, at five stations on the mainland of New Zealand and at three of the outlying islands. The determinations show that in the New Zealand region the lunar tide has a larger amplitude and smaller phase than might have been expected from previously available southern-hemisphere results. In general, the seasonal variation of phase in the New Zealand region conforms to the currently recognised global pattern, with the J-season phase greater than that of the D-season. Similarly, the amplitude variation tends to support the suggestion that, south of latitude 30°S, the D-season amplitude is greater than that of the J-season. Approximate tests are introduced and used to assess the statistical significance of some of the apparent differences in amplitude and phase made evident by the analysis. These assessments indicate that although many of the apparent differences may be attributed to sampling fluctuations, the main regional anomalies in amplitude and phase are likely to be real. It is suggested that these anomalies may indicate a significant regional input of tidal energy to the atmosphere (at the lower boundary) from the Pacific oceanic tide.
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    Pure and applied geophysics 123 (1985), S. 221-231 
    ISSN: 1420-9136
    Keywords: Travel-time residuals ; Southeastern Europe
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    Topics: Geosciences , Physics
    Notes: Abstract The Pn travel time relative residuals, in respect to a crustal model of the Aegean area, have been determined for 103 permanent seismological stations in southeastern Europe, western Turkey and the Middle East. The values of these residuals are considered to depend mainly on the crustal thickness beneath the seismological stations. Based on these values seven regions with different crustal thickness, varying between 31 Km and 42 Km, have been defined. The crust in these regions is continental. A region with very high negative residuals has been defined in the Middle East (Egypt, Israel, Lebanon). These negative residuals are attributed to different crustal structure of the eastern Mediterranean (oceanic crust with an extra thick sedimentary layer) and not the crustal thickness at the station sites. Independently from the interpretation, these Pn residuals can be used successfully to considerably improve (up to 2 Km) the determination of the earthquake foci locations.
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  • 55
    ISSN: 1420-9136
    Keywords: Lower Tropospheric Disturbances ; Tropics ; Regional characteristics of disturbances
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Regional characteristics of the synoptic-scale wave disturbances in the tropical lower troposphere were examined by analyzing the FGGE level III-b data. Three tropical regions, western Pacific, eastern Pacific, and a region from the African Continent to the Atlantic, were selected for the present study. Spectrum analysis, trajectory analysis and composite analysis were used to obtain characteristics of the wave disturbances for each region. Main findings are as follows: 1.) The generation region of the western Pacific wave disturbances related to typhoon development are found around 5° N and 170° E. 2.) An interaction of the western Pacific wave disturbances with the upper Mid-Pacific trough was indicated statistically as an intensifying condition for typhoons. 3.) The wave disturbances in the eastern Pacific originate to the west of Panama and propagate west-north-westward with a period of 5.7 day and a wavelength of about 2700 km. 4.) The structure of the eastern Pacific wave disturbances is similar to that of the western Pacific disturbances. 5.) Two different paths of the African waves are found over the African Continent. The northern disturbance has a period of 4.4 days while the southern one has a period of 3.3–3.6 days. 6.) Disturbances along the northern path of the African waves are traced only to as far as 45° W, and those along the southern path are traced to the Caribbean Sea.
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  • 56
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    Pure and applied geophysics 123 (1985), S. 398-406 
    ISSN: 1420-9136
    Keywords: Geophysical explanation ; Ireegular variations ; Mean latitudes ; Stress propagation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Mean latitude variations computed by Orlovs or other filters have some irregular variations in addition to secular ones. These are of the order of ±0.05 to ±0.1, they can last several years and sometimes show regional similarities. In looking for an explanation of such latitude variations several physical mechanisms have been investigated. The most probable one is the mechanism of stress propagation in the lithosphere and asthenosphere. The consequent gravitational and deformational effects could explain both the magnitude and the time dependance of the irregular latitude variations.
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    Pure and applied geophysics 123 (1985), S. 441-447 
    ISSN: 1420-9136
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    Notes: Abstract This note examines the accuracy of finite difference solutions of the midlatitude primitive equations and the quasi-geostrophic equation. First order accurate forward differencing of the equations' lower boundary condition is shown to poorly simulate the radiating wave response to midlatitude heating. Forward differencing always exaggerates the magnitude of the radiating response. For a realistic heating height scale and for a reasonable mesh size this exaggeration is on the order of 50%. Central differencing of the lower boundary condition gives an error of only about 3%.
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    Pure and applied geophysics 123 (1985), S. 487-498 
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  • 59
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    Pure and applied geophysics 123 (1985), S. 468-475 
    ISSN: 1420-9136
    Keywords: Seasonal precipitation ; eigenvector ; spatial similarity
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    Topics: Geosciences , Physics
    Notes: Abstract Three extreme cases of seasonal precipitation over 31 contiguous meteorological subdivisions of India were decomposed into orthogonal components using eigenvector technique to examine their spatial and temporal behaviour. The first two eigenvectors combined were found to represent the seasonal precipitation over India to a sufficient high degree of accuracy retaining 90–95 percent of the total variance. These two components show high spatial similarity in all the three cases of the precipitation examined. The first component is characterized by a coherent variation over the area with large coherent variation over the north-east India, Central India and the west coast of India. The coefficients of the component show annual behaviour with the peak values generally reached during July. This component is representative of the summer monsoon (June–September) mode. The second component characterizes out of phase variation in precipitation between Central India, adjoining parts of the area, and peninsular India. The coefficients of the component show the semi-annual oscillation. It appears that the role of the second eigenvector might be to represent regionality of the seasonal march of the monsoon rain.
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    Pure and applied geophysics 123 (1985), S. 501-501 
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    Pure and applied geophysics 123 (1985), S. 503-542 
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    Notes: Abstract This paper presents the theory which describes how the lateral correlation of vertical displacement is influenced by multiple scattering of seismic waves caused by the presence of fluid-filled fractures, along with an observational methodology to show how to extract fracture-related quantities (e.g. fracture porosity, degree of anisotropy of the fractures, change in orientation of the fractures, density of fluid filling the fractures) from seismic data using the theoretical development as an underpinning framework. A simple physical picture is given of the basic process, as well as some rough order of magnitude estimates to show that the parameters quantifying the size of the multiple scattering fall squarely in the seismic regime. These calculations serve to create a basis to determine, by seismic means ahead of the drill, (1) the degree of fracturing of reservoir rocks (such as the Monterey shale), and (2) the type of fluid filling the fractures.
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    Pure and applied geophysics 123 (1985), S. 580-596 
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    Notes: Abstract Calculations of viscous damping chracteristics of gravity waves, propagating obliquely across finite monomolecular films, are represented graphically to demonstrate the influence of angle of incidence, film edges, and surfactant properties. It is found that regions of negative damping may occur, particularly towards the rear of extensible slicks. For wide slicks, both the amplitude and the domain of significant edge effects on the local damping coefficient decrease with angle of incidence. Multiple-slick systems can damp waves more effectively—with appropriate choice of surface-active material—than an equivalent single slick.
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  • 63
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    Pure and applied geophysics 123 (1985), S. 610-623 
    ISSN: 1420-9136
    Keywords: Radiative-convective model ; Cloud feedback ; Temperature
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    Topics: Geosciences , Physics
    Notes: Abstract The effect of cloud feedback on the response of a radiative-convective model to a change in cloud model parameters, atmospheric CO2 concentration, and solar constant has been studied using two different parameterization schemes. The method for simulating the vertical distribution of both cloud cover and cloud optical thickness, which depends on the relative humidity and on the saturation mixing ratio of water vapor, respectively, is the same in both approaches, but the schemes differ with respect to modeling the water vapor profile. In scheme I atmospheric water vapor is coupled to surface parameters, while in scheme II an explicit balance equation for water vapor in the individual atmospheric layers is used. For both models the combined effect of feedbacks due to variations in lapse rate, cloud cover, and cloud optical thickness results in different relationships between changes in surface temperature, planetary temperature, and cloud cover. Specifically, for a CO2 doubling and a 2% increase in solar constant, in both models the surface warming is reduced by cloud feedback, in contrast to no feedback, with the greater reduction in scheme I as compared to that of scheme II.
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  • 64
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    Pure and applied geophysics 123 (1985), S. 667-682 
    ISSN: 1420-9136
    Keywords: Earthquake cycles ; fault dynamics ; loading rates
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    Notes: Abstract The occurrence of cyclical instabilities along plate boundaries at regular intervals suggests that the process of earthquake causation differs in some respects from the model of elastic rebound in its simplest forms. The model of tectonic feedback modifies the concept of this original model in that it provides a physical interaction between the loading rate and the state of strain on the fault. Two examples are developed: (a) Central Chile, and (b) Mexico. The predictions of earthquake hazards for both types of models are compared.
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    Pure and applied geophysics 123 (1985), S. 697-705 
    ISSN: 1420-9136
    Keywords: Volcanic earthquakes ; statistical analysis ; Mt. Etna
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    Topics: Geosciences , Physics
    Notes: Abstract Seismic activity that preceded, accompanied, and followed the 17–23 March 1981 Etnean eruption has been statistically analyzed. On the grounds of both time evolution of seismicity and catalogue completeness, three time intervals have been defined (12 February–2 March, 12–17 March, 19–31 March) and for each of these periods both the “b” coefficient of theGutenberg-Richter's (1956) relationship and the “E” parameter of the cluster size (Shlien andToksoz, 1970) have been calculated. No significant variations were observed between the first and third periods, while lower values of bothb andE coefficients were found in the second one. These findings might indicate that changes in the seismicity features occur just before the eruption start. Small but fast variations in the stress field acting on the volcano might originate this type of seismic activity, while the importance of the tectonic control on volcanic phenomena seems to be confirmed.
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  • 66
    ISSN: 1420-9136
    Keywords: Seismic risk ; extreme values ; strain energy ; circum-Pacific
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    Notes: Abstract In a previous paper (Makropoulos andBurton, 1983) the seismic risk of the circum-Pacific belt was examined using a ‘whole process’ technique reduced to three representative parameters related to the physical release of strain energy, these are:M 1, the annual modal magnitude determined using the Gutenberg-Richter relationship;M 2, the magnitude equivalent to the total strain energy release rate per annum, andM 3, the upper bound magnitude equivalent to the maximum strain energy release in a region. The risk analysis is extended here using the ‘part process’ statistical model of Gumbel's IIIrd asymptotic distribution of extreme values. The circum-Pacific is chosen being a complete earthquake data set, and the stability postulate on which asymptotic distributions of extremes are deduced to give similar results to those obtained from ‘whole process’ or exact distributions of extremes is successfully checked. Additionally, when Gumbel III asymptotic distribution curve fitting is compared with Gumbel I using reduced chi-squared it is seen to be preferable in all cases and it also allows extensions to an upper-bounded range of magnitude occurrences. Examining the regional seismicity generates several seismic risk results, for example, the annual mode for all regions is greater thanm(1)=7.0, with the maximum being in the Japan, Kurile, Kamchatka region atm(1)=7.6. Overall, the most hazardous areas are situated in this northwestern region and also diagonally opposite in the southeastern circum-Pacific. Relationships are established between the Gumbel III parameters and quantitiesm 1(1),X 2 and ω, quantities notionally similar toM 1,M 2 andM 3 although ω is shown to be systematically larger thanM; thereby giving a physical link through strain energy release to seismic risk statistics. Inall regions of the circum-Pacific similar results are obtained forM 1,M 2 andM 3 and the notionally corresponding statistical quantitiesm 1(1),X 2 and ω, demonstrating that the relationships obtained are valid over a wide range of seismotectonic enviroments.
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    Pure and applied geophysics 123 (1985), S. 707-731 
    ISSN: 1420-9136
    Keywords: Induction logging ; Computer modeling ; Borehole Turam ; Borehole Slingram ; Layered earth ; Mineral and groundwater investigation
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    Topics: Geosciences , Physics
    Notes: Abstract In a general treatment of the theory of induction logging, an exact integral representation has been obtained for the mutual impedance between a vertical dipole transmitter and a coaxial dipole receiver in a three layered earth. Based on this representation, a computer model has been devised using the traditional Slingram system of induction logging and the comparatively new Turam system, ignoring borehole effects. The model results indicate that due to its much larger response, the Turam system is in general preferable to the Slingram in mineral and groundwater investigations where formation conductivity much less than 1 S/m is generally encountered. However, if the surrounding media are conductive (more than 0.1 S/m), the Turam system suffers from large amplitude attenuation and phase rotation of the primary field caused by the conductive surrounding, and is less useful than the Slingram system which does not so suffer, unless the target bed is shallow. Because it is a more complex function of system parameters than the corresponding Slingram log, a Turam log can be conveniently interpreted only by the modern inverse method using a fast algorithm for the forward solution and a high speed digital computer.
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    Pure and applied geophysics 123 (1985), S. 791-803 
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    Pure and applied geophysics 123 (1985), S. 837-848 
    ISSN: 1420-9136
    Keywords: Atalandi fault ; normal faulting ; leveling ; post-seismic slip ; aseismic slip ; geomorphology
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    Topics: Geosciences , Physics
    Notes: Abstract Repeated leveling data collected over a 14-km long traverse, crossing the Atalandi fault that last broke in 1894, revealed small amplitude motions for the interval 1969–1984. These motions are significant against random errors and are probably free of systematic errors. In addition, no local or superficial ground effect may account for the observed elevation changes which correlate with the tectonic pattern in the area, as they show a relative downward motion of the hanging wall of a normal fault. This motion is similar to the co-seismic slip. Geomorphological observations and observations of submerged archaeological sites on the other hand corroborate long-term motions which are unlikely to be explained as cumulative co-seismic slip and are possibly similar to the short-term motions leveling data reveal.
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    Pure and applied geophysics 123 (1985), S. 882-892 
    ISSN: 1420-9136
    Keywords: thin sheet ; induced polarization ; resistivity ; borehole ; conductive slab ; dilution factor
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    Notes: Abstract The relevant potential theory is given for a current point source in the presence of a conductive slab embedded in a homogeneous host region of infinite extent. The thin sheet representation is obtained from the exact integral formulation by a simple mathematical limit process. The same result is also deduced directly at the outset by applying a thin sheet boundary condition. The apparent resistivity for a two electrode array is then computed for the case where the bore hole intersects the thin sheet at right angles. The corresponding results for the dilution factor, relevant to the induced polarization response, are also obtained. It is shown that the apparent resistivity and the dilution factor are constant when the potential and the current electrode straddle the sheet but there is a characteristic decrease as the electrodes move away from the sheet.
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    Pure and applied geophysics 123 (1985), S. 893-901 
    ISSN: 1420-9136
    Keywords: Magnetic anomalies ; dipping beds ; faults ; anticlines ; magnetic equivalence ; ambiguity in interpretation
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    Notes: Abstract The interpretation of magnetic anomalies of dipping beds with an inclined top is ambiguous. The magnetic anomaly profile over a dipping bed can be produced by a series of beds of different dips and directions of magnetization. Further, these anomalies are equivalent to those of faults and anticlines. Thus, the magnetic anomaly profiles, assumed to be produced by one of the models, can also be produced by the other models. The ambiguity is resolved in case of dipping beds and faults, when the magnetization is caused purely by induction; but the case of anticlinal beds remains ambiguous. The magnetic equivalence of dipping beds, anticlines, and faults makes it possible to apply the available methods of interpretation of fault models to dipping beds and anticlines.
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    Pure and applied geophysics 123 (1985), S. 902-920 
    ISSN: 1420-9136
    Keywords: Atmospheric tides
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    Topics: Geosciences , Physics
    Notes: Abstract The relationships between the linearized meteorological variables as expressed in geometric height and in log-pressure coordinates are derived from the assumptions of classical atmospheric tidal theory. While the horizontal velocity components are the same to first-order in the two coordinate systems, a linearized vertical velocity differencew′-H 0ω′ occurs because of the periodic vertical displacement of the constant pressure surfaces due to time-dependent, hydrostatic density perturbations; a linearized temperature differenceT′-τ′ also results when these displacements occur in the presence of a zero-order vertical gradient of temperature. Both of these differences can be expressed in terms of the tidal geopotential field. For a given tidal mode, both differences are generally proportional to the square root of the ratio of the tidal mode's equivalent depth and the atmospheric scale height; the temperature difference is also proportional to the background temperature lapse rate. It is further shown that the two classical tidal vertical structure equations commonly derived in their respective geometric height and log-pressure coordinate systems are in fact identical to first-orderas long as the same thermotidal forcing function is used. Expressions for the zonal-mean components of the tidal bilinear fluxes, formed by zonally averaging the product of two longitudinally varying, linearized tidal fields, are also derived for the two coordinate systems. For the bilinear fields the largest relative differences (a few tens of percent) are for the tidal zonal-mean forcing per unit mass of the zonal wind. For Earth and Mars, differences between the tidal vertical velocity fields are generally less than 25% but may be significantly larger in the Martian atmosphere during one of its episodic planetary-scale dust storms. Tidal temperature differences are generally smaller.
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    Pure and applied geophysics 123 (1985), S. 951-959 
    ISSN: 1420-9136
    Keywords: Teleconnections ; Northeast Brazil
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    Notes: Abstracts Linear correlation coefficients are calculated between the geopotential heights for the winter months (December, January, and February) at 700 mb in the Northern Hemisphere and the March rainfall over Northeast Brazil. Isolines of correlation coefficients showed interesting patterns and regions of significantly high correlation. The occurrence of PNA pattern is interpreted as a connection between the Northern Hemisphere winter circulation and NE Brazil rainfall through El Niño—Southern oscillation phenomena. The negative center over North-West United States in the PNA pattern also has a direct relationship to the NE Brazil rainfall. Further studies are needed to substantiate and understand the teleconnections noted here.
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    Pure and applied geophysics 124 (1986), S. 31-52 
    ISSN: 1420-9136
    Keywords: Fault gouge ; friction ; deformation textures
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    Topics: Geosciences , Physics
    Notes: Abstract The frictional properties of a crushed granite gouge and of gouges rich in montmorillonite, illite, and serpentine minerals have been investigated at temperatures as high as 600°C, confining pressures as high as 2.5 kbar, a pore pressure of 30 bar, and sliding velocities of 4.8 and 4.8×10−2 μm/sec. The gouges showed nearly identical strength behaviors at the two sliding velocities; all four gouges, however, showed a greater tendency to stick-slip movement and somewhat higher stress drops in the experiments at 4.8×10−2 μm/sec. Varying the sliding velocity also had an effect on the mineral assemblages and deformation textures developed in the heated gouges. The principal mineralogical difference was that at 400°C and 1 kbar confining pressure a serpentine breakdown reaction occurred in the experiments at 4.8×10−2 μm/sec but not in those at 4.8 μm/sec. The textures developed in the gouge layers were in part functions of the gouge type and the temperature, but changes in the sliding velocity affected, among other features, the degree of mineral deformation and the orientation of some fractures.
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    Pure and applied geophysics 124 (1986), S. 79-106 
    ISSN: 1420-9136
    Keywords: Deformation ; faults ; cataclasis ; gouge ; rock mechanics
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    Topics: Geosciences , Physics
    Notes: Abstract Field observations of the Punchbowl fault zone, an inactive trace of the San Andreas, are integrated with results from experimental deformation of naturally deformed Punchbowl fault rocks for a qualitative description of the mechanical properties of the fault and additional information for conceptual models of crustal faulting. The Punchbowl fault zone consists of a single, continuous gouge layer bounded by zones of extensively damaged host rock. Fault displacements were not only localized to the gouge layer, but also to discrete shear surfaces within the gouge. Deformation in the exposure studied probably occurred at depths of 2 to 4 km and was dominated by cataclastic mechanisms. Textural data also suggest that significant amounts of pore fluids were present during faulting, and that fluid-assisted mechanisms, such as dissolution, diffusion, and precipitation, were operative. The experimental data on specimens collected from the fault zone suggest that there is a gradual decrease in strength and elastic modulus and an increase in relative ductility and permeability toward the main gouge zone. The gouge layer has fairly uniform mechanical properites, and it has significantly lower strength, elastic modulus, and permeability than both the damaged and the undeformed host rock. For the Punchbowl fault and possibly other brittle faults, the variations in loading of the gouge zone with time are primarily governed by the morphology of the fault and the mechanical properties of the damaged host rock. In addition, the damaged zone acts as the permeable unit of the fault zone and surrounding rock. It appears that the gouge primarily governs whether displacements are localized, and it therefore may have a significant influence on the mode of slip.
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    Pure and applied geophysics 124 (1986), S. 141-157 
    ISSN: 1420-9136
    Keywords: Seismic refraction ; mylonites ; fractures ; seismic reflection ; low velocity zone ; microcracks
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    Topics: Geosciences , Physics
    Notes: Abstract The internal properties within and adjacent to fault zones are reviewed, principally on the basis of laboratory, borehole, and seismic refraction and reflection data. The deformation of rocks by faulting ranges from intragrain microcracking to severe alteration. Saturated microcracked and mildly fractured rocks do not exhibit a significant reduction in velocity, but, from borehole measurements, densely fractured rocks do show significantly reduced velocities, the amount of reduction generally proportional to the fracture density. Highly fractured rock and thick fault gouge along the creeping portion of the San Andreas fault are evidenced by a pronounced seismic low-velocity zone (LVZ), which is either very thin or absent along locked portions of the fault. Thus there is a correlation between fault slip behavior and seismic velocity structure within the fault zone; high pore pressure within the pronounced LVZ may be conductive to fault creep. Deep seismic reflection data indicate that crustal faults sometimes extend through the entire crust. Models of these data and geologic evidence are consistent with a composition of deep faults consisting of highly foliated, seismically anisotropic mylonites.
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    Pure and applied geophysics 124 (1986), S. 269-288 
    ISSN: 1420-9136
    Keywords: Cataclasites ; ductile shear zones ; microstructures
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    Notes: Abstract Brittle-to-ductile shear zones from two separate geological settings are shown to have nucleated on zones of predominantly brittle deformation. The shear zones are not simply foliated cataclasites, since they contain abundant evidence of dynamic recrystallization of constituent minerals. A small quartz diorite lens in the Borrego Springs shear zone, southern California, contains centimeter-scale cataclasite zones that exhibit a gradual transition into foliated rock. Alteration of magnesiohornblende to actinolite, feldspar to white mica plus quartz, and biotite to chlorite, produced elongate minerals that define the foliation. During the later stages of deformation, intracrystalline slip and dynamic recrystallization of quartz and feldspar were important deformation mechanisms. The widespread occurrence of mineralized dilatant cracks predated the development of meter-to-decimeter-scale ductile shear zones in the Striped Rock granite, southern Virginia. Again, important deformation mechanisms in the final stages of deformation were intracrystalline slip and dynamic recrystallization of quartz. In both field areas the role of fluids has been important from the onset of brittle deformation. Fluids may have enhanced early fracturing in addition to causing the alteration and hydrolytic weakening of host rock minerals and the introduction of new mineral species. Each of these processes is thought to have contributed to the later localization of crystal plastic deformation in the rocks.
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    Pure and applied geophysics 124 (1986), S. 383-414 
    ISSN: 1420-9136
    Keywords: Rock friction ; constitutive behaviour ; granite ; stability of sliding ; earthquake
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    Notes: Abstract An understanding of the frictional sliding on faults that can lead to earthquakes requires a knowledge of both constitutive behavior of the sliding surfaces and its mechanical interaction with the loading system. We have determined the constitutive parameters for frictional sliding of initially bare surfaces of Westerly granite, using a recently developed high pressure rotary shear apparatus that allows long distances of sliding and therefore a greater assurance of attaining steady state behavior. From experiments conducted at room temperature and normal stresses of 27–84 MPa several important results have been found. (1) A gouge layer 100 to 200 μm thick was developed from the initially bare rock surfaces after 18 to 70 mm of sliding. (2) The steady state frictional resistance, attained after about 10 mm of sliding, is proportional to the negative of the logarithm of the sliding velocity. (3) Abrup changes in the velocity of sliding result in initial changes in the frictional resistance, which have the same sign as the velocity change, and are followed by a gradual decay to a new steady state value over a characteristic distance of sliding. This velocity weakening behavior is essentially identical with that found by several previous workers on the same material at lower normal stress. (4) Our results are well described by a two state variable constitutive law. The values of the constitutive parameters are quite similar to those found previously at low normal stress, but the characteristic distance is about an order of magnitude smaller than that found at 10 MPa normal stress with thicker layers of coarser gouge. (5) We have approximated our results with a one state variable constitutive law and compared the results with the predictions of existing nonlinear stability analysis; in addition, we have extended the stability analysis to systems possessing two state variables. With such formulations good agreement is found between the experimentally observed and theoretically predicted transitions between stable and unstable sliding. These results allow a better understanding of the instabilities that lead to earthquakes.
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    Pure and applied geophysics 124 (1986), S. 515-529 
    ISSN: 1420-9136
    Keywords: Slip rate ; stress drop ; fault ; heterogeneity
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    Notes: Abstract Recent observations made by Kanamori and Allen about earthquake recurrence time and average stress drop revealed a very interesting relation: earthquakes with longer recurrence times have higher average stress drops. They attributed the difference in stress drop to the difference in long-term average slip rate. To interpret their result in terms of the healing effect, we simulated earthquake recurrence with a one-dimensional mass-spring model, incorporating a recently developed rate-and-state dependent friction law for different loading rates and heterogeneous strength distributions. We first calculated the stress drop and recurrence time as functions of loading rate for a homogenous fault model. We found that the stress drop increases up to 30% when the loading rate decreases from 10 cm/yr to 0.01 mm/yr. Thus, the observed great variability of stress drop, from a few bars to a few hundred bars, which is obtained by replotting the data of Kanamori and Allen in the form of stress drop versus long-term slip rate, may not be attributable to the healing effect alone. Our numerical simulation shows that the variability may be due primarily to the spatial heterogeneity of strength on the fault. Our simulation also suggests that of the two empirical laws that were inferred from the same laboratory friction data, called the power law and the logarithmic law by Shimamoto and Logan, the former can explain the observed relation between stress drop and slip rate better than can the latter, at least for strike-slip fault. The logarithmic law is an earlier and simpler version of the rate-state-dependent friction law.
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    Pure and applied geophysics 124 (1986), S. 793-810 
    ISSN: 1420-9136
    Keywords: Plate models ; shear and tensile source mechanisms ; seismotectonic interpretation
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    Topics: Geosciences , Physics
    Notes: Abstract A special experimental technique enabled us to study in detail seismic events on a fault model in a uniaxial stress field. The recording system used made it possible to investigate the radiation pattern for all the events observed including the precise determination of the dislocation origin. The aim of the present paper is (1) to find the relation between shear and tensile displacements, (2) to check a possible influence of the process of tensile crack generation on the seismic energy release and (3) to compare the seismic regime of a single fault before and after the tensile crack generation, respectively. Results prove the dominating importance of shear mechanism for the seismic energy release. The tensile displacement can be seismoactive only under special contact conditions on the fault plane. The existence of tensile cracks at the fault tips changed the pattern of seismic energy radiation. This feature is probably caused by subsequent changes in contact conditions on the fault plane and in the stress field around the fault. A comparison of some results of the present model experiments with the already published results of geological and seismological measurements and investigations shows the analogous character in laboratory and in nature of the process of tectonic earthquake preparation, the displacement course on the fault during the earthquake and the manner of seismic energy release on faults.
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    Pure and applied geophysics 124 (1986), S. 811-824 
    ISSN: 1420-9136
    Keywords: Earthquake modelling ; fracturing process ; precursors of failure
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    Topics: Geosciences , Physics
    Notes: Abstract One of the simplest models of earthquakes and rockbursts was studied in laboratory conditions in which the fracture was initiated in a barrier between two preexisting faults. The treated models were built of concrete; during the construction of the models, the stress concentrators were inserted inside the models. This arrangement enabled the shear displacement to occur during uniaxial loading of the model. The tests were made on the series of models, the sizes of which were mutually varying more than one order. In the process of the barrier fracture propagation, the following were investigated: the time and space changes of local deformations as well as the acoustic emission, velocities and amplitudes of elastic waves, electrical conductivity and proper electro-induction. The process of barrier fracturing can be understood in three fundamental stages. In the course of the first stage, the density of small tensile cracks increases considerably, while the volume in which they exist is gradually enlarged. In the second stage, as the result, of these cracks coupling, longer shear cracks are created. During the coupling, due to the development of numerous regions of unstable deformation, the zones of nonequal rigidity arise in the treated medium, distributed within it in a mosaic-like pattern. In the third stage, the main fracture is prepared and formed with simultaneous unloading of the surrounding medium. The process of crack forming is gradually localized into a more narrow zone. The second and third stages of fracture forming are reflected in variations of all the above-mentioned physical parameters which are therefore identified as the precursors of the main fracture. By means of the series of precursors it is possible to find the reliable prediction of a barrier fracture.
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    Pure and applied geophysics 124 (1986), S. 857-874 
    ISSN: 1420-9136
    Keywords: Fault interaction ; seismotectonic interpretation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Systems of two parallel linear faults of the same length with the angle of inclination α=45° were investigated under uniaxial linearly increasing load. Perspex plates were used as models. For each treated fault configuration the morphology of tensile cracks and the sequence of seismoacoustic events of shear and tensile origin were studied. It is shown that the seismic regime of a fault system is strongly influenced by the contact conditions on a fault plane; it is different in the faults with the aseismic contact, represented by open slits, and in the faults with the seismoactive contact, represented by filled slits, respectively. The experiments proved the dominating role of a fast shear displacement of the stick-slip type in the regime of seismic energy release of a fault system. The tensile crack generation seems to be only of little—if not negligible—importance. On the other hand, the existence of tensile cracks in a fault system can play an important role in the course of subsequent loading cycles because the stick-slip displacements can take place not only along the primary faults but also along the planes of tensile cracks. A comparison of some results of model experiments and the already published results of geological and seismological investigations indicated that the way of seismic energy relase on faults in nature and in the laboratory could be of the same character. Several analogies between the seismic regime of a fault model and of real seismic regions were found concerning the morphology of faults, off-fault fore- and aftershocks, and earthquake doublets, respectively.
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    Pure and applied geophysics 124 (1986), S. 487-513 
    ISSN: 1420-9136
    Keywords: Friction law ; magnitude-frequency relation ; seismicity simulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The dynamic motions and stabilities of a single-degree-of-freedom elastic system controlled by different friction laws are compared. The system consists of a sliding block connected to an elastic spring, driven at a constant velocity. The friction laws are a laboratory-inferred friction law called the rate-and-state-dependent friction law, proposed by Dieterich and Ruina, and a simple friction law described by dynamic and static frictions. We further extend the solution to a one-dimensional mass-spring model which is an analog of a fault controlled by the rate-and-state-dependent friction law. This model predicts non uniform slip and stress drop along the rupture length of a heterogeneous fault. This result is very different from some earlier modelings based on the simple friction law and a slip weakening friction law. In those earlier modelings the stress and slip functions become smoother with time along the length of the fault rupture, owing to the interactions between fault segments during slip. Because of this smoothing process the number of small events will decrease with time, and the universilly observed stationary magnitude-frequency relation cannot be explained. The interaction between a fault segment and its neighboring segments can be measured when the post-slip stress on this segment is compared with the stress on an identical segment (represented by a block in this modeling) without neighboring segments. If the post-slip stress of the former is much higher than that of the latter, strong interaction exists; if the two are close, only weak interaction exists. The interaction is determined by the relative motion between fault segments and the time duration of interaction. Our new modeling with the rate-and-state-dependent friction law appears to show no such smoothing effect and provides a physical mechanism for the roughening process in the difference between the fault strength and stress that is necessary to explain the observed stationary magnitude-frequency relation. The noninstantaneous healing predicted by the rate-and-state-dependent friction law may be repsonsible for the recurring nonuniform slip and stress drop, and may be explained by the reduction of interaction among fault segments due to the low frictional strength during the fault stopping. The very low friction during slip stopping allows much longer times than does the higher friction due to instantaneous healing for the fault segments to adjust their motions from an upper-limit slip velocity to almost rest. According to newton's second law, a process with fixed masses and constant velocity changes involves low forces and weak interactions if it is accomplished in a long time period, and vice versa. Our modeling also indicates that the existence of strong patches with higher effective stress on a fault is needed for the occurrence of major events. The creeping section of a fault, such as the one along the San Andreas fault in central California, on the other hand, can be simulated with the rate-and-state-dependent friction law by certain model parameters, which, however, must not include strong patches. In this case small earthquakes and aseismic creep relieve the accumulating strain without any large events.
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    Pure and applied geophysics 124 (1986), S. 531-566 
    ISSN: 1420-9136
    Keywords: Fault mechanics ; earthquakes ; crustal deformation ; San Andreas fault
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract A two-dimensional model for stress accumulation and earthquake instability associated with strike-slip faults is considered. The model consists of an elastic lithosphere overlying a viscous asthenosphere, and a fault of finite width with an upper brittle zone having an elastoplastic response and a lower ductile zone having an elastoviscoplastic response. For the brittle, or seismic, zone the behavior of the fault material is assumed to be governed by a relation which involves strain hardening followed by a softening regime, with strength increasing with depth. For the fault material in the ductile, or aseismic, section, the viscous effect is included through use of a nonlinear creep law, and the strength is assumed to decrease with depth. Hence, because of the lesser strength and the viscous effect, continuous flow occurs at great depths, causing stress accumulation at the upper portion of the fault and leading to failure at the bottom of the brittle zone. The failure is initially due to localized strain softening but, with further flow, the material above the softened zone reaches its maximum strength and begins to soften. This process accelerates and may result in an unstable upward rupture propagation. Relations are developed for the history of deformation within the lithosphere, specifically for the velocity of particles within the fault and at the ground surface. The boundary-element method is used for a quantitative study, and numerical results are obtained and compared with the recorded surface deformation of the San Andreas fault. The effects of geometry and material properties on instability, on the history of the surface deformation, and on the earthquake recurrence time are studied. The results are presented in terms of variations of ground-surface shear strain and shear strain rate, and velocity of points within the fault at various times during the earthquake cycle. It is found that the location of rupture initiation, the possibility of a sudden rupture as opposed to stable creep, and also the ground deformation pattern and its history, all critically depend on the mechanical response of the material within the fault zone, especially that of the brittle section. Shorter earthquake recurrence times are obtained for shallower brittle zones and for a stiffer lithosphere. Lower viscosities of the aseismic zone and the absence of asthenospheric coupling tend to suppress instability and promote stable creep. The model results thus suggest that the overall viscosity of the ductile creeping zone must exceed a minimum value for a sudden upward propagating rupture to take place within the seismic section.
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    Pure and applied geophysics 124 (1986), S. 609-610 
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    Pure and applied geophysics 125 (1987), S. 183-189 
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    Pure and applied geophysics 125 (1987), S. 193-204 
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    Pure and applied geophysics 125 (1987), S. 613-628 
    ISSN: 1420-9136
    Keywords: Aegean area ; seismicity rate ; Poisson process ; seismic energy release ; thermal stresses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The most complete and reliable data of strong (M s≥6.5), shallow (h〈70 km) earthquakes which occurred in the inner Aegean seismic zone have been utilized to describe its seismicity time variation during 1800–1986 by two independent statistical models. The first is a sequentially stationary model of seismicity rates which shows that intervals of low seismicity rate, lasting for some 37 years, alternate with high rate intervals of 8–12 years duration. The second model is a statistical model according which seismic energy released within 5-year time windows approximates a harmonic curve within a period of about 50 years. This model is in agreement with the notion that the time series of strong earthquake occurrences in the inner Aegean seismic zone consists of a random (shocks withM s=6.5–6.8) and a nonrandom component (M s≥6.9). Maxima and minima of the harmonic curve coincide with the high and low rate intervals, respectively. A model of regional stationary accumulation of thermal stresses along certain seismic belts and their cyclic relaxation may explain this periodicity.
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    Pure and applied geophysics 125 (1987), S. 679-698 
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    Pure and applied geophysics 129 (1989), S. 455-474 
    ISSN: 1420-9136
    Keywords: Mining-induced events ; seismic monitoring ; focal mechanism ; source parameters ; Strathcona hard rock mine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Rockbursts and mining-induced seismic events have serious socio-economic consequences for the Canadian mining industry, as their mines are extended to greater depths. Automatic multichannel monitoring systems (Electro-Lab MP250s) are routinely, used to detect the arrival times of seismic waves radiated by mining-induced events and sensed on an array of single component transducers installed throughout a mine. These arrival times are then used to locate the events and produce maps of areas of high activity for use in mine planning and design. This approach has limitations in that, it does not allow a detailed analysis of source mechanisms, which could be extracted if whole waveform signals are recorded and analyzed. A major research project, sponsored by the Natural Sciences and Engineering Research Council of Canada (NSERC) with the collaboration of the Canadian mining industry, is aimed at enhancing existing mine seismic monitoring technology in Canada, in order to carry out more advanced processing of data to obtain fundamental scientific information on mining-induced seismic events This paper describes preliminary results from seismic monitoring experiments carried out in a hard rock nickel mine in Sudbury, Canada. Existing seismic monitoring instrumentation was enhanced with a low cost microcomputer-based whole waveform seismic acquisition system. Some of the signals recorded during this experiment indicate anisotropic wave propagation through the mine rock masses, as observed by the splitting of shear waves and the relative arrival of two shear waves polarized in directions which may be related to the structural fabric and/or state of stress in the rock mass. Analysis of compressional wave first motion shows the predominance of shear events, as indicated by focal mechanism studies and is confirmed by spectral analysis of the waveforms. The source parameters were estimated fro typical low magnitude localized microseismic events during the initial monitoring experiments. The seismic moment of these events varied between 106 N.m and 2.108 N.m. with a circular source radius of between 1 m and 2 m with an estimated stress drop of the order of 1 MPa.
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    Pure and applied geophysics 129 (1989), S. 553-570 
    ISSN: 1420-9136
    Keywords: Location methods ; singular value decomposition method ; Quirke Mine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Singular Value Decomposition method of solving a linear system of equations can be successfully used for focus location when both linear and nonlinear methods are applied. This method can also be used to calculate the variance of the separate source coordinates, when the variance of the input data is known. It is also possible to optimize the geometry of a seismic network by using the condition number of the covariance matrix, and to check the set of data which is used for the focus location when some of the data are expected to be incorrect. Examples of applications of the Singular Value Decomposition method are demonstrated for linear and nonlinear methods with reference to the seismic network in Quirke Mine, Ontario, Canada.
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    Pure and applied geophysics 129 (1989), S. 609-617 
    ISSN: 1420-9136
    Keywords: Seismic hazard ; rockburst hazard ; seismic wave velocity ; stress state ; Upper Silesian coal mines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract In the Upper Silesian Coal Field the seismic hazard induced by mining operations in collieries is closely related to the rockburst hazard. A seismic method is used for premonitory recognition of the zones of seismic hazard. It takes advantage of the relationship between the velocity of propagation of seismic waves and the state of stress existing in the rock. It consists of the determination of the velocity field of artificially induced seismic waves in a studied fragment of the rock, and of locating the velocity anomaly. The position of the velocity anomaly zones and their intensity are the basis for estimating the seismic hazard in advance of mining works.
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    Pure and applied geophysics 125 (1987), S. 629-656 
    ISSN: 1420-9136
    Keywords: Earthquake ; friction ; stick-slip ; symmetry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Can a simple multi-block-spring model with total symmetry make interesting predictions for fault behaviour? Our model consists of a symmetric, slowly driven, two degree-of-freedom block-spring system with static/dynamic friction. The simple friction law and slow driving rate allow the state of this fourth order system to be described between slip events by a single variable, the difference in the stretch of the driving springs. This stretch difference measures the locked-in stress and is closely related to fault stress inhomogeneity. In general,smoothing is not observed. A spatially homogeneous stress state is found to almost always be unstable, in that the system tends toward an inhomogeneous state after many slip events. The system evolves either to a cycle that alternates between two types of earthquakes, or to a cycle with repeating but identical asymmetric earthquakes. One type of alternating earthquake solution is structurally unstable, which implies a great sensitivity to model perturbations. For this simple model, spatial asymmetry necessarily occurs, despite the symmetry in the model, thus suggesting that spatial structure in seismicity patterns may be a consequence of earthquake dynamics, not just fault heterogeneity.
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    Pure and applied geophysics 125 (1987), S. 657-668 
    ISSN: 1420-9136
    Keywords: Self-potential method ; electrical prospecting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract To date, the interpretation of the self-potential anomalies, caused by the polarized spherical ore bodies, has usually been carried out based on the special graph along the profile passing through the extremes of these anomalies. This special graph could be identified only if we have at hand a map of self-potential distribution for which many profiles should be measured needing many man powers and time. To overcome this situation, in actual paper a new method of interpretation for the above mentioned self-potential anomalies is proposed for which sufficiency is provided by only two self-potential graphs along two parallel ordinary profiles oriented fortuitously. The theoretical basis of this new method of interpretation, together with several nomograms making comfortably its use as well as some testing results, were given.
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    Pure and applied geophysics 125 (1987), S. 765-775 
    ISSN: 1420-9136
    Keywords: Reoccurrence formulas ; hazard assessment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract A modified formula of the cumulative frequency-magnitude relation has been formulated and tested in a previous paper by the authors of this study. Based on the modified relationship, the following reoccurrence formulas have been obtained. 1) For the ‘T-years period’ larger earthquake magnitude,M T $$M_T = \frac{1}{{A_3 }}ln\frac{{A_2 }}{{(1/T) + A_1 }}.$$ 2) For the value of the maximum earthquake magnitude, which is exceeded with probabilityP inT-years period,M PT $$M_{PT} = \frac{{ln(A_2 .T)}}{{A_3 }} - \frac{{ln[A_1 .T - ln(1 - P)]}}{{A_3 }}.$$ 3) For the probability of occurrence of an earthquake of magnitudeM in aT-years period,P MT $$P_{MT} = 1 - \exp [ - T[ - A_1 + A_2 \exp ( - A_3 M)]].$$ The above formulas provide estimates of the probability of reoccurrence of the largest earthquake events which are significantly more realistic than those based on the Gutenberg-Richter relationships; at least for numerous tested earthquake samples from the major area of Greece.
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    Pure and applied geophysics 126 (1988), S. 103-121 
    ISSN: 1420-9136
    Keywords: instability ; overreflection ; Orr mechanism ; wave-mean flow interaction ; Orr-Sommerfeld problem ; shear instability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract This paper reviews work done over the last twelve years on wave overreflection in shear flows, and on the development of a mechanical picture of how overreflection and instability work. It is argued that the wave geometry of a flow configuration is the primary determinant of its stability. It is also argued that the primary mechanism for wave amplification is the Orr mechanism.
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    Pure and applied geophysics 126 (1988), S. 279-318 
    ISSN: 1420-9136
    Keywords: Earthquake prediction ; precursory quiescence ; quiescence ; seismicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Precursory seismic quiescence has played a major role in most of the succesful earthquake predictions made to date. In addition to these successes, the number of detailed post-mainshock documentations of precursory quiescence is steadily growing. These facts suggest that precursory quiescence will play an important role in earthquake prediction programs of the future. For this reason it is important to critically evaluate the present state of knowledge concerning this phenomenon. The history of observations of precursory seismic quiescence includes work on seismic gaps and ‘seismic preconditions’ as well as actual studies of temporal quiescence. These papers demonstrated the importance of quantitative evaluation of seismicity rates and the benefits of systematic analysis. During the early 1980's the impact of man-made effects on seismicity rates was demonstrated for the first time. Despite progress in catalog understanding, the identification and correction of man-made seismicity changes remains as the major barrier to earthquake prediction using these data. Effects of man-made changes are apparent in many past studies of seismicity patterns, making the results difficult to evaluate. Recent experience with real-time anomalies has demonstrated the necessity of determining the false alarm rates associated with quiescence precursors. Determination of false alarm rates depends on quantitative definitions of anomalies and statistical evaluations of their significance. A number of successful predictions, which have been made on the basis of seismic quiescence, provide important lessons for present and future work. There are many presently unanswered questions regarding seismic quiescence which must be answered before we can determine the reliability of this phenomena as a precursor.
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    Pure and applied geophysics 130 (1989), S. 213-232 
    ISSN: 1420-9136
    Keywords: Middle atmosphere ; dynamics ; interhemispheric comparison
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    Topics: Geosciences , Physics
    Notes: Abstract Comparisons are drawn between certain middle atmosphere dynamical processes in the Southern Hemisphere and the Northern Hemisphere. Attention is focused on the zonal-mean climatological state, stationary waves, transient waves of various types, stratospheric sudden warmings and polar ozone minima. Observations of the similarities and differences between the hemispheres are mentioned, and ways in which these comparisons may be used to enhance our dynamical knowledge of the whole middle atmosphere are discussed.
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    Pure and applied geophysics 130 (1989), S. 171-180 
    ISSN: 1420-9136
    Keywords: Antarctic lower stratosphere ; polar vortex ; springtime warming behaviour ; radiosonde temperature observations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The behaviour of the Southern Hemisphere stratosphere has attracted considerable interest, and been compared with the Northern Hemisphere, since the International Geophysical Year (1957–58) when the sudden (“explosive” or “accelerated”) springtime warming phenomenon in the Antarctic was first observed. Over the years studies of upper air temperature and wind observations have been made, principally through the spring months when the polar vortex breakdown occurs, utilising both ground-based (rawinsonde, rocket) and more recently, satellite-derived data. Although the radiosonde-derived temperature data are limited both by the number of reporting stations, and the practical difficulty of securing observations much above the 100 hPa level, useful records exist from 1956 or 1957. These have shown that in the 1959 southern spring, the lower stratosphere was relatively colder, and the warming rate through the season was essentially more regular, with little evidence of the marked but short-lived temperature fluctuations usually found. Similar, but not quite such wide-spread conditions occurred again in the 1961 spring. In another study, 30 hPa temperature fields over the Antarctic continent, which could be drawn for the 1967 spring, showed the complexity of the polar vortex breakdown. These features are recalled because extension of the 100 hPa springtime temperature series for the Australian Antarctic station at Casey (66.3°S, 110.5°E) shows that in 1985 and part of 1986, the temperature behaviour there was similar to, but not quite so extreme as that which occurred at Mirny (66.5°S, 93.0°E) in 1959.
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