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  • Springer  (211,911)
  • 1975-1979  (211,911)
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  • 1
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Summary The external morphology of 185 specimens from a genetically determined, gynandromorph producing line was investigated. To improve the classification of the zygotic female and azygotic male tissue the recessive eyecolour mutation chartreuse and the recessive body pigment mutation cordovan were incorporated. The whole body surface was subdivided into 50 organs or sections of organs. After classifying the sexual character of each of the 50 units mentioned above, male tissue was rated 0, female tissue 2 and mosaic pattern 1. In regard to the participation of male and female tissue in the outer morphology of the 185 gynandromorphs there were a greater number of specimens which showed a higher portion of male structures. But also gynandromorphs were found which looked nearly completely like drones or like worker bees, only tiny patches of tissue of the opposite sex could be identified on these organisms. Nearly all of the 50 organs or sections of organs showed a similar statistical distribution between the two sexes. Only compound eyes and ocelli had a higher tendency to maleness. Difficulties were encountered in the sexual classification of several organs; among these were the wings. Here shape and the bristle distribution on their surfaces sometimes indicated different sexual origins. The gonads showed this difficulty too. A comparison was made between the proportional number of zygotic and azygotic energids during early embryological stages and the final imaginal expression of the gynandromorphs. Explanations for the origin of the observed differences are given.
    Notes: Zusammenfassung Aus einer genetisch determinierten, Gynandromorphen erzeugenden Linie wurden 185 Individuen in Hinblick auf ihre äussere Morphologie untersucht. Die Unterscheidung des zygot entstandenen weiblichen und azygot entstandenen männlichen Gewebes war mit Hilfe der rezessiven Augenmutation chartreuse und der rezessiven Körperpigmentmutation cordovan erleichtert. Die Körperoberfläche teilte ich in 50 Organe oder Organbereiche auf, deren geschlechtliche Ausprägung einzeln bestimmt wurde; männliches Gewebe erhielt den Wert 0, weibliches den Wert 2, Mosaikstruktur den Wert 1. Eine Aufgliederung der Organismen in Hinblick auf ihren Anteil an männlichem und weiblichem Gewebe ergab ein Uebergewicht der Tiere mit höherem männlichen Gewebeanteil. Es waren jedoch auch Typen mit nahezu einseitiger männlicher oder weiblicher Ausprägung vorhanden. Alle umgrenzten 50 Organe bzw Organbereiche erfuhren eine annähernd gleichmäßige statistische Aufteilung auf die beiden Geschlechter. Bei den Komplexaugen und Ocellen dominierte die männliche Ausprägung. Die Schwierigkeit eindeutiger geschlechtlicher Zuordnung einiger Organe wurde an den Flügeln demonstriert. Form und Borstenverteilung auf der Oberfläche zeigten mehrfach unterschiedliche geschlechtsspezifische Ausbildung. Für die schwierige geschlechtliche Klassifizierung der inneren Organe bilden die Gonaden ein Beispiel. Vergleiche zwischen den Zahlenwerten azygoter und zygoter Energiden im frühembryonalen Stadium und der imaginalen Ausprägung wurden vorgenommen und mögliche Ursachen für die proportionale Umverteilung während der Ontogenese aufgezeigt.
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  • 2
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Summary In five spruce bogs of the Saguenay region in Québec the density of the antFormica dakotensis (Formicidae, Hymenoptera) varies from 174 to 7 colonies per hectare. This large variation of the density can be correlated with the physical and vegetation characteristics of the habitats. The observed density for the surveyed hectare of Saint-Ambroise is compared with densities estimated by sampling surfaces varying in size, number and distribution. The results show clearly that a study of an ant species productivity is influenced from the beginning by a number of variables which may give erroneous data if wrongly defined.
    Notes: Résumé Formica dakotensis (Formiciaae, Hymenoptera) affiche dans cinq pessières tourbeuses de la région du Saguenay, Québec, des densités variant de 174 à 7 colonies par hectare. Cette variation importante de la densité peut être mise en relation avec celle des caractéristiques physiques et végétales des biotopes étudiés. Les densités estimées à l'aide de surface-échantillons dont nous avons fait varier la dimension, le nombre et la répartition sont comparées à la densité observée pour l'hectare prospecté à Saint-Ambroise. Les résultats indiquent clairement que pour entreprendre une étude sur la productivité d'une espèce de fourmi, il faut tenir compte d'un certain nombre de paramètres, afin d'éviter de recueillir dès le départ des chiffres erronés.
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  • 3
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    Insectes sociaux 22 (1975), S. 207-212 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Nous décrivons le cycle annuel de croissance et de récolte des termitières d'Odontotermes redemanni (Wasmann). La croissance du tumulus est rapide de novembre à mars, lorsque les précipitations et les températures ambiantes sont faibles. Le rythme de croissance des tumulus diminue à mesure que leur hauteur croît; la croissance s'arrête lorsque la hauteur atteint 2 mètres. L'activité de récolte est nocturne et courante de mars à septembre. Il y a une corrélation positive entre la surface de l'aire de récolte et la taille du tumulus.
    Notes: Summary The annual cycles of growth and foraging in the mounds of the eastern Indian mound building termiteOdontotermes redemanni (Wasmann) are described. The growth of the mound is rapid during November to March when both the rainfall and ambient temperature are low. Growth rate of the individual mounds declines as the mounds increase in height and stops at 200 cm. Foraging is nocturnal and common during March to September. The area foraged increases with the size of the mound and a positive correlation exists between them.
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  • 4
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    Insectes sociaux 22 (1975), S. 225-235 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé 1. Une simulation du creusement de tunnels parFormica lemani a été réalisée à l'aide d'un computeur digital. Le modèle a permis de reproduire le taux d'excavation et certaines caractéristiques de la forme des tunnels creusés par cette espèce. 2. Le modèle appliqué àLasius niger a simulé correctement la forme des tunnels réels, mais a sous-estimé leur profondeur. 3. Chez les deux espèces, la variation individuelle des tunnels simulés est moins grande que celle des tunnels réels. Ceci pourrait être dû au fait que le modèle ne tient pas compte des différences entre fourmis. 4. Le modèle n'a pu reproduire les embranchements des tunnels deL. niger, ni les dédoublements de ceux deF. lemani.
    Notes: Summary 1. A computer model of the excavation behaviour of the antFormica lemani has simulated the rate of excavation and some features of the form of its tunnels. 2. The same model applied to another antLasius niger simulated the form of tunnels correctly but underestimated the depth of its tunnels. 3. In both species the individual variation predicted between different tunnels was less than that actually observed. This seems to be explained by the fact that the model did not incorporate individual differences between ants. 4. The model was unable to generate the branches ofL. niger tunnels, or the duplicated tunnels ofF. lemani.
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  • 5
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Summary The influence of endogenous factors on the brood cycle and production of sexuals was investigated on laboratory colonies of the Myrmicine ant,Monomorium pharaonis (L.). This cycle is characterized by regular production of sexuals at intervals of 3–4 months; in between pure worker broods are produced. Both the number and the quality of the queens are very important for the length of the brood cycles: by removing all or some of the queens from the colony the differentiation of sexuals can always be induced — this impliestrophogenic caste determination. In «queenright» colonies sexual broods are induced at intervals of 3–4 months byphysiological queenlessness. On the grounds of her differential inhibition of sexual broods the life period of a queen can be divided into 3 phases: thejuvenile phase (partially inhibiting), the fully fertile phase (totally inhibiting) and thesenile phase (partially inhibiting sexual broods). Apart from this size and age of theworker population are important. During the breeding cycle an «avalanche of workers» develops; this is shown by the growth of the worker numbers as well as by the increasing weight of the newly emerging workers. In addition to physiological queenlessness the differentiation of sexuals occurs if the number of workers per queen exceeds a certainthreshold value, provided that the worker population mainly consists of nursing-workers. As the queens ofM. pharaonis generally are very short-lived (usually less than 200 days), one brood cycle approximately corresponds to their life cycle. The queens are superseded in their function by their first (and only) fertile descendants, so that there is always just one fully fertile generation of queens in the colony. This phenomenon seems to be unique in the polygynous Formicidae.
    Notes: Zusammenfassung Der Einfluß populationseigener Faktoren auf Brutzyklus und Geschlechstieraufzucht der polygynen MyrmicineMonomorium pharaonis L. wurde experimentell untersucht. Dieser Zyklus zeichnet sich durch die ± regelmäßige Aufzucht von Geschlechtstieren im Abstand von 3–4 Monaten aus; dazwischen liegen reine Arbeiterinnenbruten. Es konnte festgestellt werden, daß sowohl die Quantität als auch die Qualität der vorhandenen Königinnen für die Länge des Brutzyklus eine entscheidende Rolle spielt: durch Teil- oder Totalentweiselung läßt sich stets die Aufzucht von Geschlechstieren auslösen, ein Hinweis auftrophogene Kastendeterminierung. In der weiselrichtigen Kolonie werden Geschlechtstieraufzuchten durchphysiologische Weisellosigkeit induziert. Aufgrund der unterschiedlichen Hemmwirkung auf die Geschlechstieraufzucht kann das Leben der Königinnen in 3 Phasen eingeteilt werden:Juvenilphase (partiell hemmend), vollfertile Phase (total hemmend) undsenile Phase (partiell hemmend). Daneben sind Größe und Alter der Arbeiterinnenpopulation von Bedeutung: im Laufe des Brutzyklus entsteht eine Arbeiterinnenlawine, die sich außer im Zuwachs an Arbeiterinnen auch in einer steten Gewichtszunahme der neu schlüpfenden Arbeiterinnen manifestiert. Zusätzlich zur physiologischen Weisellasigkeit wirkt die Ueberschreitung eines bestimmtenSchwellenwertes von Arbeiterinnen zu Weibchen auslösend auf die Differenzierung neuer Geschlechtstiere. Weitere Voraussetzung ist allerdings, daß die Arbeiterinnenpopulation überwiegend aus Jungarbeiterinnen besteht. Da die Königinnen vonM. pharaonis extrem kurzlebig sind (im Normalfall weniger als 200 Tage) entspricht ein Brutzyklus in etwa ihrem Lebenszyklus. Die Königinnen werden von ihren ersten (und einzigen) fertilen Nachkommen in ihrer Funktion abgelöst, sodaß immer nur eine voll fertile Weibchengeneration in der Sozietät vorhanden ist. Dieses Phänomen ist für polygyne Formiciden-Arten bisher einmalig.
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  • 6
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    Insectes sociaux 22 (1975), S. 405-414 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung In zwei Kolonien der polygynen Form vonFormica rufa L. wurden Weibchen mit vergrößerten Labialdrüsen gefunden. Sie unterschieden sich von normalen Weibchen durch braune Flecken auf dem schwarzen Scutum und ein etwas vergrößertes und abnormal gewölbtes Pronotum. Die Paarung dieser Weibchen verlief normal, danach wurde festgestellt daß die Spermatheca mit lebendem Sperma gefüllt war. Ihre Nachkommenschaft bestand aus normalen Arbeiterinnen und Arbeiterinnen mit vergrößerten Labialdrüsen (Wasmanns «Pseudogynen», Novaks «Secretergaten»). Es gab Hinweise daß, wenn sie überhaupt über Flugvermögen verfügen, dieses geringer ist als das der normalen Weibchen.
    Notes: Summary Females with enlarged labial glands were found in two colonies of the polygynous form ofFormica rufa L. They were distinguishable from normal females by more or less extensive brown patches on otherwise black scutums, and by slightly enlarged pronotums. They mated in the ordinary way; afterwards they were found to have their spermathecas full of living sperm and later produced normal workers and workers with enlarged labial glands (Wasmann's «pseudogynes», Novak's «secretergates»). There were indications that the power of flight, if any, was poorer than that of normal females.
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  • 7
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    Insectes sociaux 23 (1976), S. 99-107 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Resumen Las ninfas y adultos deAethalion reticulatum fueron encontrados alimentandose dePiper umbellatum en Costa Rica. Las hembras protegian sus huevos sentados encima de ellos y frotundo los miembros posteriores con los lados de las masas de huevos. Dos parasitos fueron criados en los huevos,Gonatocerus sp. yPterygogramma sp. Ninfas y adultos eran protegidos regularmente por losCamponotus sericeiventrisyCamponotus (Tanaemyrmex) sp. LosC. sericeiventris cuidaban a las hemipteras durante las horas del día solamente y las protegian agresivamente. LosCamponotus (Tanaemyrmex) sp. fueron desalojados en competencia por las especies primarias.
    Abstract: Résumé Nous avons trouvé des nymphes et des imagos deAethalion reticulatum qui se nourrissaient surPiper umbellatum à Costa Rica. Les femelles protégeaient leur amas d'œufs en se tenant à leur sommet et en frottant leurs pattes arrières sur les côtés de l'amas. Deux parasitoïdes,Gonatocerus sp. etPterygogramma sp., furent élevés au sein des amas d'œufs.Camponotus sericeiventris etCamponotus (Tanaemyrmex) sp. prenaient réguliérement soin des nymphes et des imagos. C'est seulement le jour queCamponotus sericeiventris s'occupait des Hémiptères et les protégeait de façon agressive.Camponotus (Tanaemyrmex) sp. était supplantée par l'espèce précédente, plus compétitive.
    Notes: Summary Aethalion reticulatum nymphs and adults were found feeding onPiper umbellatum in Costa Rica. Adult females protected their egg masses by sitting atop the masses and scraping their hind legs along the sides. Two parasitoids,Gonatocerus sp. andPterygogramma sp. were reared from egg masses. Nymphs and adults were regularly tended byCamponotus sericeiventris andCamponotus (Tanaemyrmex) sp.Camponotus sericeiventris tended only during the daylight hours and aggressively protected the hemipterans.Camponotus (Tanaemyrmex) sp. was competitively displaced by the former species.
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  • 8
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    Insectes sociaux 23 (1976), S. 155-165 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Les ailés et reproducteurs primaires sont peu nombreux dans les colonies trouvées sur le terrain dans les troncs et les souches décomposées sur le sol. Les colonies dénombrées apparaissent relativement petites par rapport à celles des termites supérieurs et la plupart possèdent des sexués de remplacement (une paire ou davantage). La corrélation existant entre la largeur de la tête et le nombre des denticulations de la plaque molaire des mandibules montre qu'il existe 7 stades larvaires. Les couples de reproducteurs supplèmentaires élevés au laboratoire à température constante de 15°, 20° ou 25°C produisent du couvain; la formation du couvain est inhibée à 28°C. Bien qu'une température de 25°C soit la plus favorable pour la fondation d'une colonie, la température de 20°C semble préférable pour un élevage de plus longue durée.
    Notes: Summary Alates and primary reproductives were scarce in field colonies which were found in damp decaying logs and stumps on the forest floor. Colonies counted were found to be relatively small compared with those of higher termites and most were found to be headed by a pair or more of supplementary reproductives. A strong correlation was found between headwidth and the number of larval plate ridges on the right mandible which indicated that inP. adamsoni the basic number of larval instars is seven. Pairs of supplementary reproductives held at constant temperatures of 15°, 20° and 25°C produced brood; brood production was inhibited at 28°C. Although 25°C was more satisfactory for the development of primary colonies, 20°C appeared to be more satisfactory for continued development of colonies.
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  • 9
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    Insectes sociaux 23 (1976), S. 49-73 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Summary Puric and mineral accumulation sites in Termites are located into fat body, Malphigian tubules and epiderma. The cations stored are numerous: Ca, Mg, K, Mn, Fe, Zn, Na. Their nature and quantities depend on the species as well as on the stage and the cast. Interference of food with bioaccumulation is evident only if the element ingested is exceptionnaly abundant. Thus iron is present inCubitermes and only in those casts which feed on mould (workers, soldiers). In workers, one must also insist on a perticular feature ofCubitermes which contrary to other species, stores very little. The soldiers, in contrast, appear rather homogenous (high storage in fat body and Malpighian tubules). The evolution leading to nymphs and winged adults represents always in the life cycle of the species the most important pathway as far as bioaccumulation is concerned. Soldiers nymphs and winged adults ofSchedorhinotermes, soldiers and nymphs ofMicrocerotermes andCubitermes are fed by trophallaxy; the particular social behaviour of these two casts is the same in the three species. Thus, some physiological and ethological features species specific and casts specific, favour the puric and mineral bioaccumulation.
    Notes: Résumé Les sites d'accumulation minérale et purique des Termites sont localisés dans le tissu adipeux, les tubes de Malpighi et l'épiderme. Les cations accumulés sont nombreux: Ca, Mg, K, Mn, Fe, Zn, Na. Leur nature et leur quantité dépendent à la fois de l'espèce, du stade et de la caste. L'intervention directe d'une substance alimentaire dans la bioaccumulation n'est évidente que lorsque la nourriture apporte un élément exceptionnellement abondant. Ainsi, le fer n'est présent que chezCubitermes et seulement dans les castes nourries d'humus (ouvriers, soldats). Dans la caste des ouvriers, il faut aussi insister sur le particularisme desCubitermes qui, contrairement aux autres espèces, accumulent peu. La caste des soldats apparaît, par contre, assez homogène (indice d'accumulation du tissu adipeux élevé; fort stockage malpighien). L'évolution qui conduit aux nymphes et aux ailés représente toujours, dans le cycle d'une espèce, la voie la plus importante du point de vue de la bioaccumulation. Soldats et lignée sexuée deSchedorhinotermes, soldats et nymphes deMicrocerotermes etCubitermes sont nourris par trophallaxie, et le comportement social général caractérisant chacune de ces deux «castes» est uniforme dans les trois espèces. Certaines particularités physiologiques et éthologiques propres aux espèces et aux castes concourent donc à l'établissement des divers aspects de la bioaccumulation minérale et purique.
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  • 10
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Nous avons étudié les facteurs qui influencent la dispersion géographique, le comportement et l'intensité de récolte, le choix de la récolte, le nombre d'ouvrières récolteuses dans chaque société, l'intervalle entre les nids ainsi que la structure des nids dePogonomyrmex rugosus et dePogonomyrmex barbatus. Nous avons décelé des variations saisonnières dans le comportement de récolte.P. barbatus s'est montrée plus active au début de l'été et a récolté la nuit, tandis queP. rugosus a présenté une pointe d'activité au milieu de l'été, la récolte de nuit se faisant en juillet. Les deux espèces ont manifesté une préférence pour les graines de graminées, mais ont récolté aussi d'autres matériaux. Là où les deux espèces cohabitaient, leur indice d'empiétement pour les récoltes était de 0,7. Les sociétés appartenant aux deux espèces étaient réparties au hasard. La densité des sociétés s'élevait à environ 20 par hectare dans les sites qui abritaient soit l'une soit les deux espèces. Aucune preuve d'agression intraspécifique n'est apparue bien que les territoires de récolte de la même espèce aient été largement imbriqués.P. barbatus etP. rugosus évitent la concurrence par le choix de l'habitat. L'agression interspécifique explique probablement l'absence d'empiétement des deux espèces dans la distribution locale des colonies.
    Notes: Summary Factors affecting local geographic distribution, foraging behavior and activity, forage selection, numbers of foragers per colony, nest spacing and nest structure ofPogonomyrmex rugosus andPogonomyrmex barbatus wer estudied. There were seasonal differences in foraging activity.P. barbatus was more active in early summer and foraged at night whileP. rugosus was more active in mid-summer foraging at night during July. Both species exhibited forage preference for grass seeds but took a variety of other materials. Where both species inhabited the same area they had an index of overlap for forage of 0.7. The colonics of both species were randomly distributed. Colony density was approximately 20 per hectare in areas supporting one or both species. There was no evidence of intraspecific aggression and foraging areas of colonies of the same species overlapped considerably.P. barbatus andP. rugosus avoid competition by habitat selection. Interspecific aggression probably accounts for the lack of overlap in local distribution.
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  • 11
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    Insectes sociaux 23 (1976), S. 199-200 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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  • 12
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    Insectes sociaux 23 (1976), S. 215-225 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Summary Observations on the sexual behaviour of the guest ant were made in laboratory colonies. The females ofFormicoxenus, which occur in a complete morphological intergradation from workerlike individuals to alate females, show a «Locksterzel» behaviour just like that described inHarpagoxenus sublaevis and other social parasites of the tribeLeptothoracini. During this behaviour the gaster is raised, the sting extruded, and a small droplet of a secretion becomes visible at its tip. The ergatoid, wingless males are attracted by such females over a distance of about 15 cm. They try to mount not only «calling» females but also others crawling around in the arena. Mating behaviour of males can also be released by squashed abdomens of females, and by isolated poison glands, but not by other glands or parts of the females body. The pheromone also released homosexual behaviour among the males. The mating behaviour is described.
    Notes: Zusammenfassung Das Sexualverhalten der Gastameise wurde in Laborvölkern untersucht. Die Weibchen vonFormicoxenus, die in einer kompletten morphologischen Uebergangsreihe von arbeiteringleichen zu geflügelten Vollweibehen vorkommen, zeigen ein «Locksterzel»-Verhalten wie es fürHarpagoxenus sublaevis und andere Sozialparasiten des TribusLeptothoracini beschrieben wurde. Während dieses Verhaltens ist die Gaster angehoben, der Stachel wird ausgestreckt und an seiner Spitze erscheint ein kleiner Sekrettropfen. Die ergatoiden, flügellosen Männchen werden von solchen Weibchen über etwa 15 cm Entfernung angelockt. Sie versuchen nicht nur auf sterzelnde Weibchen aufzureiten, sondern auch auf andere, die in der Arena umherlaufen. Durch zerquetschte Weibchen-Gaster und durch isolierte Giftdrüsen kann bei Mänchen ebenfalls Sexualverhalten ausgelöst werden, jedoch nicht durch andere Drüsen oder Körperteile von Weibchen. Das Pheromon löst auch homosexuelles Verhalten unter den Männchen aus. Das Begattungsverhalten wird beschrieben.
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  • 13
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    Insectes sociaux 23 (1976), S. 263-275 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Das Bindegewebe vonApis ist aus drei Bestandteilen zusammengestezt: aus einer armorphen Substanz, aus feinen und elektronendichten Fäden und aus Fibrillen, die dem Kollagen gleichen. Dieses Material bildet die verschiedenen Strukturen des Bindegewebes: äussere Verkleidung der Zellen bzw. der Basalmembranen, elektronendichte Hüllen, Neurallamellen, Binde- oder Aufhänge-Membranen, Hohlstränge, die Organe verbinden, Filamente, die Zellen untereinander verbinden und amorpher Substanz, die die Zellen einbetten. die Verkeleidung der Zellen und die Bindemembranen werden nur aus amorphen Stoffen gebildet, die Hohlstänge aus amorphen Stoffen, sowie aus dünnen Filamenten und Kollagen. Die Neurallamellen bestehen aus amorpher Substanz and Kollagen, die elektronendichte Verkleidungen aus amorpher Substanz und dünnen Fibrillen.
    Notes: Summary The connective tissue ofApis appears to have three components: amorphous substances, fine and dense filaments and collagen-like-fibrils. These materials form the various structures comprising the connective tissiue that are: external coast or basement membranes, dense coast, neural lamellae, connective or suspending membranes, hollow strands connecting organs, filaments attaching cells, and amorphous substances cementing cells. The external coast and connective membranes are formed of only amorphous substances. The hollow strands are formed of amorphous substances, thin filaments and collagen. The neural lamellae are formed of amorphous substances and collagen and the dense coast of amorphous substances and thin filaments.
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  • 14
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    Insectes sociaux 24 (1977), S. 131-146 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Summary 1o A count of the number of adults and pupae ofPheidole pallidula (Nyd.) found in the field shows that the percentage of soldiers varies as the year goes on: low at the end of hibernation, it increases to a maximum at the begining of winter. 2o It is possible to reproduce these fluctuations in the laboratory thus permitting an analysis of the factors regulating the appearance of soldiers at the end of hibernation. a) The age of the workers with respect to the end of hibernation does not seem to be relevant. In fact, workers that have been out of hibernation for several weeks and that have already reared a brood of workers are no more adapted to the rearing of soldiers than those that have just come out hibernation. b) In spite of a seasonal change in their size, the eggs are bipotential: spring and summer eggs are both able to give rise to soldiers and to workers. Even the eggs of founding queens can develop into soldiers larvae. The direction in which they develop depends on the treatment they receive and not on a blastogenic factor. c) The abundance of nursing workers enhances the number of soldiers hatched. d) At the end of hibernation the production of soldiers is inhibited when the percentage of adult soldiers is greater than about 4% even if there are several thousand nurse workers. We can thus explain the absence or low numbers of soldiers in the first spring brood: in colonies having more than 5% of adult soldiers there is an inhibition of the rearing of new soldiers in favour of the production of workers; the hatching of lowers the percentage of these soldiers thus removing the inhibition. What is more the percentage of soldiers above which there is inhibition rises throughout the year so allowing an accumulation of new born soldiers.
    Notes: Résumé 1o Le recensement des adultes et des nymphes dans la nature dePheidole pallidula montre que le pourcentage des soldats varie en cours d'année: faible à la sortie de l'hibernation, il s'élève progressivement et atteint son maximum à l'entrée de l'hiver. 2o Il est possible de reproduire ces variations au laboratoire, ce qui permet d'analyser les facteurs régulant l'apparition des soldats à la sortie de l'hibernation. a) L'âge des ouvrières par rapport à la sortie d'hibernation semble sans effets. En effet, des ouvrières sorties d'hibernation depuis plusieurs semaines et qui ont déjà élevé un couvain d'ouvrières ne sont pas plus aptes à l'élevage des soldats que celles sortant d'hibernation. b) Malgré une évolution saisonnière de leur taille, les œufs sont bipotentiels: les œufs de printemps et les œufs d'éte sont susceptibles de donner naissance à des soldatset à des ouvrières. Même les œufs des reines fondatrices peuvent évoluer en larves de soldats. L'orientation dépend des soins donnés aux larves et non d'un facteur blastogénique. c) L'abondance des ouvrières nourrices, favorise l'éclosion des soldats en plus grand nombre. d) Toujours à la sortie de l'hibernation, la production des soldats est inhibée lorsque le pourcentage des soldats adultes est supérieur à environ 4% même si il y a plusieurs milliers d'ouvrières nourrices. Dès lors, on peut expliquer l'absence ou le faible nombre de soldats dans le premier couvain produit au printemps: les colonies possèdent plus de 5% de soldats adultes, d'où inhibition de l'élevage de nouveaux soldats au profit de la production d'ouvrières; l'éclosion de ces dernières fait chuter le pourcentage des soldats, ce qui lève l'inhibition. De plus, le pourcentage des soldats en dessus duquel il y a inhibition s'élève au cours de la saison, permettant alors l'accumulation des soldats nouveau-nés.
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    Insectes sociaux 24 (1977), S. 268-268 
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    Insectes sociaux 24 (1977), S. 273-273 
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    Insectes sociaux 24 (1977), S. 286-289 
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    Insectes sociaux 24 (1977), S. 297-302 
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    Description / Table of Contents: Summary For the first time a symposium was organized on technology and maintenance methods for bee flight rooms. The experiences in several laboratories showed that by now generally the new technology as published byvan Praagh in 1972 is adopted. Considerable success was recorded: Maintaining tropical species ofApis (A. dorsata andA. florea) for more than one year in a flight room in Europe, over-wintering susceptible races and mutants in spite of cold climate, keeping queens after artificial insemination in micronuclei until egg laying. In spite of this, the conditions in a flightroom do not yet equal the conditions in the open (no increase of colony strenght over a certain level, no stimulation of swarming behavior, no drone rearing). The possible reasons for this and ways of improvement are discussed.
    Notes: Zusammenfassung Erstmals wurde ein Symposium über die Technologie und über die Haltungsmethoden für Bienenvölker in Flugräumen abgehalten. Wie die Berichte aus mehreren Laboratorien zeigten, wird heute allgemein die neue Technologie angewandt, dievan Praagh (1972) publieziert hat. Es wird über beträchtliche Erfolge berichtet: Haltung von tropischenApis-Arten (A. dorsata undA. florea) über einen Zeitraum von mehr als einem Jahr in einem Flugraum in Europa. Ueberwinterung empfindlicher Rassen und Mutanten in Gebieten mit kaltem Klima. Haltung von Königinnen nach der instrumentellen Besamung in Kleinstvölkchen bis zum Zeitpunkt der Eiablage. Dennoch erreichen die Bedingungen im Flugraum hinsichtlich des biologischen Effektes nicht das Niveau der Haltung im Freien (kein Anwachsen der Volksstärke über ein bestimmtes Maß, keine Anregung zur Schwarmtendenz, keine Aufzucht von Drohnen). Die möglichen Ursachen für diese Erscheinungen und Wege zu einer Verbesserung wurden diskutiert.
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    Description / Table of Contents: Résumé Le sac infrabuccal d'Acromyrmex octospinosus retient des particules en suspension dans la nourriture, dont le diamètre peut n'être que de 10 μm. Cette poche sert de réceptacle pour des matières prélevées sur les jardins à champignons, sur le corps même des fourmis, et pour de la cire léchée sur les feuilles utilisées dans la culture du champignon. Les pelotes rejetées de la poche infrabuccale des ouvrières contiennent des spores de champignons contaminants. Elles ont toujours été retrouvées loin des meules, le plus souvent sur les tas de détritus. Les femelles vierges cependant régurgitent leurs pelotes sur les jardins à champignons. Le champignon des fourmis a pu être cultivé sur des plaques d'agar, sur lesquelles des pelotes d'ouvrières ont été étalées. Les ouvrières n'ont pas été capables de débuter une nouvelle culture de champignons, mais l'utilisation par les reines du sac infrabuccal pour inséminer les nouveaux jardins lors des fondations de colonie peut être considérée comme un cas particulier d'un comportement plus général.
    Notes: Summary The leaf-cutting antAcromyrmex octospinosus was shown to filter out into its infrabuccal pocket from liquid food, particles down to ten μ in diameter. The pocket acted as a receptacle for material licked from the ants' fungus garden and from their own bodies, and for leaf wax licked from leaves used for fungus culture. The infrabuccal pellets of worker ants, which might contain contaminating fungal spores, were always found away from the fungus garden and mostly on the refuse dump. Virgin queens however, regurgitated their pellets onto the fungus garden. Pellets regurgitated by worker ants were streaked onto agar plates, and from these the ant fungus was cultured. Worker ants were not able to start a new fungus garden, but the use of the infrabuccal pocket by queens to transmit the ant fungus to newly founded colonies can be seen as part of a general behaviour pattern.
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    Insectes sociaux 25 (1978), S. 303-313 
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    Description / Table of Contents: Zusammenfassung In den Staaten vonOdontotermes stercorivorus (Sj.) entstehen Nymphen nur einmal im Jahr. Sie treten jedoch nicht in allen Nestern auf und ihre Anzahl pro Nest schwankt erheblich. Nymphen erscheinen im Nest schubweise. Sie entstehen zusammen mit Larven in Eikammern, die der Königinkammer benachbart liegen. Die alten Nymphen entfernen sich von den Eikammern und die geflügelten Geschlechtstiere sammeln sich schliesslich in Kammern an der Peripherie der Nester. Äussere Faktoren, insbesondere das Klima und das Nahrungsangebot könnten alljährlich die Entstehung von Nymphen auslösen, die jahreszeitlich artspezifisch festliegt. Ob jedoch in einem bestimmten Jahr in den einzelnen Nestern Nymphen auftreten oder nicht und in welcher Anzahl scheint abhängig zu sein von internen Faktoren.
    Notes: Summary In colonies ofOdontotermes stercorivorus (Sj.), nymphs appear only once annually. They are not to be found in all colonies of a similar size and their numbers show great variation from nest to nest. Nymphs originate and develop in batches, together with larvae, in egg chambers near to the queen. The older nymphs move from the egg chambers and the alatae congregate in chambers at the periphery of the nest. External factors, such as climate and foraging conditions, may be important as releasers of the annual nymphal production, the time of which is species specific. But whether or not nymphs occur in a nest in any particular year and in what numbers, seems to be more dependent on internal factors.
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    Description / Table of Contents: Summary The authors investigated the possible existence in ants of differences in the amounts of sugar food given to the queen and worker larvae by the workers. Experimental groups of the AntPlagiolepis pygmaea, rearing worker biased or queen biased larvae, were fed on honey containing radio-actively labeled gold (Au108). Upon introduction of the tracer, the groups were incubated at 26° for 4, 6, 8, 10 and 12 days. The radio-activity of the larvae was measured after 25, 48 and 76 hours. This permits a comparative estimation of the quantity of material which has been given to larval feeding from the crop of the workers. It can be only some radio-active honey ingested by the workers; but the salivary secretions of the larvae could also, in the interval, add a small quantity to the honey. The results show that,weight for weight, the queen larvae receive much more food coming from crop than the worker larvae. This difference, which is very slight until the 8th day of incubation, becomes obvious on the 9th day and reaches its maximum on the 10th and 11th days: the queen larvae receive, at this time, up to 6 times more food, weight for weight, than the worker larvae. We note that it is at the moment when the weight increase of the queen larvae is at its highest that the quantitative difference in the received sugary matter, weight for weight, is also at its highest. The authors think that the very high sugar content of the diet of queen larvae does not come into play until after caste determination has occurred.
    Notes: Résumé Les auteurs ont recherché s'il existe, chez les Fourmis, des différences dans les quantités d'aliments sucrés données par les ouvrières aux larves de reines et aux larves douvrières. Des groupes expérimentaux de la FourmiPlagiolepis pygmaea, élevant des larves d'ouvrières ou des larves de reines, ont été nourris avec du miel contenant de l'or radioactif (Au108). Lors de l'introduction du radio-élément, les groupes sont élevés à 26°C depuis 4, 6, 8, 10 et 12 jours. La radio-activité des larves est mesurée au bout de 25, 48 et 76 heures. Elle permet une estimation comparative de la quantité de substances qui a servi à l'alimentation des larves, en provenance du jabot des ouvrières. Il peut s'agir seulement du miel radio-actif ingéré par les ouvrières; mais des sécrétions salivaires ont pu aussi, dans l'intervalle, s'y ajouter en petite quantité. Les résultats montrent que,par unité de poids, les larves de reine reçoivent beaucoup plus de substances provenant du jabot que les larves d'ouvrières. Peu sensible ou faible jusqu'au 8e jour de la mise en élevage, cette différence devient très nette à partir du 9e jour, et atteint son maximum les 10e et 11e jours: les larves de reines reçoivent alors, par unité de poids, jusqu'à 6 fois plus de nourriture que les larves d'ouvrières. On constate que c'est au moment où la croissance pondérale des larves de reines est la plus importante que la différence quantitative dans les matières sucrées reçues, par unité de poids, est la plus forte. Les auteurs estiment que cette alimentation très riche en sucre des larves de reines n'intervient qu'après le déterminisme de la caste.
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    Insectes sociaux 25 (1978), S. 323-337 
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    Description / Table of Contents: Zusammenfassung 1. Honigbienen bevorzugen bestimmte Nistplatzeigenschaften. Die folgenden Bevorzugungen wurden herausgefunden («〉» bedeutet «bevorzugt gegenüber»): Höhe des Nestes, 5〉1 m; Fläche des Eingangs, 12,5〉75 cm2; Lage des Eingangs, Boden〉Spitze; Richtung des Eingangs, nach Süden〉nach Norden; Raum der Nesthöhle, 10〈40〉100 Liter. 2. Die Daten deuten darüber hinaus an, dass Honigbienen Nesthöhlen bevorzugen, die vorher bewohnt waren, oder die weiter als 300 m vom Mutterstock entfernt sind. 3. Exponierte und gut sichtbare Nistplätze werden schneller bezogen als weniger exponierte und weniger gut sichtbare Plätze. Wahrscheinlich hat dies aber seinen Grund darin, dass diese Plätze leichter entdeckt werden, nicht weil sie echt bevorzugt werden. 4. Keine Bevorzugung wurde für die folgenden Variablen gefunden: Form des Eingangs (Schlitz vs. Kreis), Form der Nesthöhle (Quader vs. hohe Rechtecksäule), Zugigkeit der Höhle (zugfrei vs. zugig) und Trockenheit (feucht vs. trocken). Wahrscheinlich sind Zugigkeit und Trockenheit der Höhle für die Biene wichtig. Da die Bienen jedoch ihr Nest abdichten und wasserdicht machen können, sind sie — was diese Nistplatz-Variablen angeht — nicht so wählerisch als gegenüber jenen, die sie nicht ändern können. 5. Dieser komplexe Prozess der Nistplatzwahl kommt der Honigbiene offensichtlich in verschiedener Weise zugute, z. B. zur Erleichterung der Verteidigung und Hygiene des Stockes, der Vereinfachung beim Nestbau und bei der Kontrolle des Mikroklimas, sowie zur Minderung der Futterkonkurrenz mit dem Muttervolk.
    Notes: Summary 1. Honey bees exhibit preferences in several nest site properties. The following preferences were identified («〉» means «preferred to»): nest height, 5〉1 m; entrance area, 12.5〉75 cm2; entrance position, bottom 〉top of nest cavity, entrance direction, southward〉northward; nest cavity volume, 10〈40〉100 liters. 2. The data also suggest preferences exist for previously inhabited nest cavities and for nest sites beyond 300 m from the parent colony. 3. Nest sites with high exposure and visibility were occupied more rapidly than sites with low exposure and visibility. However, this difference probably reflects differential ease of nest site discovery rather than a preference for exposed nest sites. 4. No preferences were found in the following variables: entrance shape (slit vs. circle), nest cavity shape (cube vs. tall parallelepiped), cavity draftiness (sound vs. drafty), and cavity dryness (wet vs. dry). Cavity draftiness and dryness are probably important to bees, but because bees can seal and waterproof their nests, they may be less demanding about these two nest site variables than about those they cannot modify. 5. The complex process of nest site selection apparently benefits a honey bee colony in several ways, including facilitation of colony defense and hygiene, simplification of nest construction and microclimate control, and reduction of foraging competition with the parent colony.
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    Description / Table of Contents: Summary During 45 months we have followed daily manyAnomma nigricans Ill. colonies in the Lamto area and we noticed that one society can divide and produce several times a new colony at short notice. For example the colonies ES and YT have respectively founded 3 and 2 new societies in 134 and 65 days. Other societies remained undivided for long periods. Two to four emigrations occuring at short intervals are observed between the statary phases necessary to the breeding of the sexual brood. A comparison between the different scissions and the time required for breeding mâles indicates that colonies can proceed to a secund cycle of foundation even before the end of the first one. Dans deux colonies, les fréquences de scissions paraissent exceptionnelles. Sur 46 autres colonies régulièrement suivies, nous n'avons, en effet, observé que 14 scissions. On peut s'interroger sur la cause d'une telle disparité? L'âge des reines serait-il en jeu? Il est bien difficile de répondre pour l'instant, la longévité et, en même temps, la grande mobilité des colonies d'Anomma rendant cette étude particulièrement difficile.
    Notes: Resume Nous avons suivi quotidiennement et pendant 45 mois de nombreuses colonies d'Animma nigricans Ill., dans la région de Lamto, en Côte d'Ivoire. Ceci nous a permis de constater qu'une même fourmilière pouvait se scinder et donner naissance à une nouvelle colonie plusieurs fois de suite en peu de temps. Nous citons le cas de deux colonies, ES et YT, qui ont produit respectivement 3 et 2 sociétés nouvelles en 134 et 65 jours. Par contre d'autres sociétés restent sans se reproduire pendant des périodes très longues. Entre les temps d'immobilisation des colonies, nécessaires à l'élevage du couvain sexué, on a observé de 2 à 4 déménagements très rapprochés. L'étude de la chronologie des scissions, comparée au temps nécessaire pour le développement du couvain mâle, permet d'affirmer qu'un processus de scission peut succéder à un autre avant même que le premier ne soit complètement achevé.
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    Insectes sociaux 26 (1979), S. 85-91 
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    Description / Table of Contents: Resume Des groupes expérimentaux, entièrement constitués de pseudergates deCoptotermes formosanus Shiraki, se sont différenciés librement au laboratoire pendant 4, 8 ou 12 semaines. Les pourcentages moyens de pseudergates qui se sont différenciés en soldats ou en soldats blancs ont été de 3,8 pour cent au bout de 4 semaines, 14,2 pour cent au bout de 8 semaines et 21,9 pour cent au bout de 12 semaines. La différenciation en soldat a été influencée par la taille initiale du groupe et le lieu d'origine de la colonie. Des groupes composés initialement de 100 pseudergates ont produit significativement une proportion plus faible de soldats que des groupes de 300, 500 ou 1000. Des colonies qui venaient d'être récoltées dans la nature ont fourni des taux significativement plus élevés de soldats qu'une colonie qui était gardée au laboratoire depuis 8 ans. Le nombre de soldats obtenu était en corrélation hautement positive avec le nombre total d'individus au bout de 4, 8 et 12 semaines. Ceci indique qu'il existe un mécanisme physiologique précis dans la régulation des proportions de soldats dans les colonies. Nous avons aussi constitué des groupes expérimentaux qui comprenaient des proportions «normales» (24%), «en dessous de la normale» et «au dessus de la normale» de soldats par rapport aux pseudergates. Lorsque la proportion de soldats était «en dessous de la normale», il y a eu inhibition de la production de présoldats de sorte que le développement en présoldats a progressivement diminué à mesure que la proportion de soldats par rapport aux pseudergates approchait de la «normale».Coptotermes formosanus Shiraki peut tolérer et maintenir une proportion remarquablement élevée de soldats (environ 38%), ce qui est bien au dessus de la proportion considérée comme «normale». Un grand nombre (mais pas tous) des soldats en surnombre ont été probablement éliminés par cannibalisme. Des groupes suchargés en soldats ont succombé à la contamination microbienne après que les soldats en surnombre fussent morts de faim. Je conclus de ces résultats que les colonies deCoptotermes formosanus gardent des soldats en proportion constante.
    Notes: Summary Experimental groups of 100 percent pseudergates ofCoptotermes formosanus Shiraki were set up in the laboratory and allowed to differentiate for either 4, 8 or 12 weeks. The average percentage of pseudergates differentiating into presoldiers and soldiers at these time intervals was 3.8, 14.2, and 21.9 percent, respectively. Differentiation to the soldier caste was affected both by initial group size and colony origin. Groups initially composed of 100 pseudergates produced a significantly smaller proportion of soldiers than did groups of 300, 500, or 1000. Recently collected field colonies produced soldiers at significantly higher rates than one which had been maintained in the laboratory for 8 years. The number of soldiers produced was highly correlated with the total number of all individuals at 4, 8, and 12 weeks, which indicates a precise physiological mechanism for regulating soldier proportions. Experimental groups were also set up with “normal” (24 percent), “below normal”, and “above normal” initial proportions of soldiers with pseudergates. ‘When soldiers were present in “below normal” proportions they inhibited the presoldier production, approached the norm. This species can tolerate and will maintain an exceptionally high proportion of soldiers (ca. 38 percent) which is far above the assumed “normal” proportion. Many, but not all, of the excess soldiers were probably eliminated by cannibalism. Groups severely overloaded with soldiers succumbed to microbial contamination after the excess soldiers starved to death. From these results I conclude that colonies ofC. formosanus do maintain numerically constant proportions of soldiers within broad limits. Thus, colonies might be controlled by chemically inducing the production of superfluous soldiers. Successful control would require the proportion of soldiers be so great that the pseudergates could not effectively reduce the numbers of soldiers by cannibalizing the excess individuals before their death by starvation resulted in microbial contamination of the entire colony.
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    Insectes sociaux 26 (1979), S. 147-153 
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    Description / Table of Contents: Resume Les travaux précédents ont montré que les ouvrières deVespa orientalis sont capables de bâtir un rayon en l'absence de la reine (Ishay, 1973, 1975, 1976). Le présent travail examine d'une manière plus approfondie la construction du rayon par des ouvrières sans reine en groupes de taille différente (2, 12–17, 44–50 ouvrières). Les résultats ont montré que l'augmentation de la taille du groupe avait un effet défavorable sur le nombre de cellules du rayon ainsi que sur la structure de la construction. Les capacités de construction varient selon les individus: quelques-uns seulement construisent correctement, quelques autres incorrectement, et la grande majorité ne construit pas du tout. La durée du séjour des ouvrières à l'intérieur d'un groupe de construction est importante: les ouvrières qui ont été isolées après avoir séjourné à l'intérieur d'un groupe montrent une diminution de la tendance à bâtir; mais, parmi celles qui sont capables de construire, un plus grand nombre construit correctement.
    Notes: Summary In previous papers (Ishay, 1973; 1975; 1976) it was reported thatVespa orientalis workers are capable of building a comb in the absence of a queen. The present paper investigates further the comb building behaviour of queenless workers, arranged in groups of various sizes (2, 12–17, 44–50 workers), and of single isolated workers. Increasing group size was found to have an adverse effect on the amount and nature of the comb construction. The building abilities of various workers varied considerably. When isolated singly, only few workers built correctly, some built incorrectly and many failed to build altogether. Workers isolated immediately after emergence showed a greater tendency to build than workers isolated 3 or 4 days after emergence.
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    Insectes sociaux 26 (1979), S. 19-37 
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    Topics: Biology
    Description / Table of Contents: Resume L'observation des jeunes sociétés de FourmisTapinoma erraticum (Dolichoderinae) a permis de classer les individus en fonction de leur activité dans l'approvisionnement du nid, celui-ci est effectué par des ouvrières spécialisées: les pourvoyeuses. On reconnaît 3 catégories d'ouvrières:les pourvoyeusss permanentes; elles sont pourvoyeuses dans plus de 80 % des observations et ne sont jamais nourrices, lespourvoyeuses intermittentes (de 20 % à 80 %) qui peuvent être simultanément pourvoyeuses et nourrices de larves, enfin les nourrices strictes (moins de 20 % des observations) qui s'occupent presque exclusivement du couvain. Le comportement est en relation avec l'âge: les ouvrières sont d'abord nourrices, ensuite pourvoyeuses intermédiaires et enfin pourvoyeuses permanentes. Les fourmis âgées de moins d'un mois sont en grande majorité nourrices (65 %), quelques-unes sont pourvoyeuses intermittentes (35 %). Parmi les ouvrières âgées de plus d'un mois 60% sont pourvoyeuses intermittentes, 30% pouroyeuses permanentes et 10 % restent nourrices. Les jeunes ouvrières deviennent en quelques jours de bonnes nourrices et soignent activement les larves alors qu'elles sont très mauvaises donneuses envers les autres ouvrières. A partir d'un mois, la majeure partie des ouvrières entre dans un pool d'individus disponibles selon les besoins de la colonie, ils sont pourvoyeurs mais peuvent aussi nourrir les larves ou la reine. La plus grande partie de l'approvisionnement est assurée par les pourvoyeuses permanentes qui sont de vieilles ouvrières et peuvent présenter une préférence alimentaire marquée vers des aliments de type sucré ou protéique L'évolution individuelle est très variable, elle peut être influencée par la pression sociale: s'il manque des pourvoyeuses âgées et c'est le cas lorsque le nombre de jeunes ouvrières est supérieur à celui des ouvrières âgées, les jeunes de moins d'un mois peuvent devenir momentanément pourvoyeuses.
    Notes: Summary The study of alimentary behaviour in newly founded societies of antsTapinoma erraticum (Dolichoderinae) with marks on the gaster enabled us to classify the individuals in terms of foraging and brood care. There are 3 different groups: permanent foragers (foragers in more than 80% observations), intermittent foragers (between 20 to 80%) and nurses (less than 20%). The behaviour of ants changes with age: young ants are nurses at first, them they are intermittent foragers, and permanent foragers at last. Ants less than one month old are calledyoung (under laboratory conditions): 65% of them are nurses, some are intermitent foragers (35%). Ants more than one month old are calledold: 60% are intermittent foragers, 30% permanent foragers and 10% only nurses. Young workers become nurses very quickly (in a few days) but they are not active donors to other workers. After one month most of them become members of a pool of unemployed ants able to forage and give food to the queen or larvae. Most of the foraging is done by permanent foragers, older workers. Individual development is very variable, according to social pressure, if there are not enough old foragers, young ants become foragers. This phenomenon can be reversible.
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    Insectes sociaux 26 (1979), S. 61-68 
    ISSN: 1420-9098
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    Topics: Biology
    Description / Table of Contents: Zusammenfassung 12 Proben vonFormicoxenus hirticornis (Emery) wurden im August 1977 im Yellowstone Park, Wyoming, aus 4 Nestern vonFormica obscuripes entnommen. Die entflügelten Weibchen und Intermorphen sowie einige Arbeiterinnen wurden seziert. Alle 16 Weibchen und 13 der Intermorphen waren begattet, doch legten nur 10 Weibchen und 4 Intermorphe Eier. des Volk scheint normalerweise nur ein voll fertiles und daneben einige zusätzliche, begattete, aber sterile Weibchen oder Intermorphe zu enthalten. Diese Ergebnisse sind unseren Beobachtungen an der europäischen GastameiseFormicoxenus nitidulus (Nyl.) sehr ähnlich. Wir schließen daraus, daßF. hirticornis (und vielleicht auch der nahe verwandteF. diversipilosus) wieF. nitidulus undLeptothorax gredleri Mayr funktionell monogyn ist, das heißt, daß überzählige begattete Weibchen und Intermorphe in weiselrichtigen Sozietäten zwar akzeptiert, aber durch einen bisher unbekannten Mechanismus steril gehalten werden. Leptothorax hirticornis Emery undL. diversipilosus M.R. Smith gehören meines Erachtens in die GattungFormicoxenus, da sie eine Anzahl einzigartiger Merkmale mitF. nitidulus gemeinsam haben: Die Männchen aller drei Arten sind flügellos und arbeiterinähnlich, alle drei leben als Gastameisen in Hügelnestern vonFormica-Arten, und sie haben einen merkwürdigen Polymorphismus mit entflügelten und intermorphen königinnen neben normalen Arbeiterinnen.
    Notes: Summary 12 samples ofFormicoxenus hirticornis (Emery) were collected from 4Formica obscuripes nests in the Yellowstone Park, Wyoming, in August, 1977. The dealate females and intermorphs, and some workers were dissected. All 16 females and 13 of the 16 intermorphs were inseminated, but only 10 females and 4 intermorphs were egg-laying. It seems that each colony normally contains only one fully fertile specimen, and a few additional, inseminated but sterile females or intermorphs. These results are very similar to our observations on the European guest-antFormicoxenus nitidulus (Nyl.). We conclude thatF. hirticornis (and maybe the closely relatedF. diversipilosus, too) is functionally monogynous likeF. nitidulus andLeptothorax gredleri Mayr, which means that supernumerary inseminated females and intermorphs are accepted in queenright colonies, but they are kept sterile by a mechanism which is not yet known. Leptothorax hirticonis Emery andL. diversipilosus M.R. Smith in my opinion belong to the genusFormicoxenus, since they have, together withF. nitidulus, a number of unique, common characters: The males of all three species are wingless and workerlike, they all live as guest ants in the mound nests ofFormica species, and they have a peculiar female polymorphism with both dealate and intermorphic queens besides normal workers.
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    ISSN: 1420-9098
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    Topics: Biology
    Description / Table of Contents: Summary Females and immatureElasmucha grisea form an association in which the mother protects its offsprings at longest to the fourth instar. The cohesion of the protective association is assured by a trail substance which is released by the larvae when moving over the surface. Both larvae (with exception of the first instar) and mother can follow such trails. A definitively perceptible trail is first produced after the passage of several larvae (with instar 3 five larvae). A trail laid by twenty larvae (instar 3 and 4) can still be followed by larvae after half an hour. The defensive secretion ofElasmucha grisea larvae and adults has an additional alarm function. It releases attack reactions in the protecting female, i.e. a directed movement toward the source of odor and wing fanning. With exception of the first instar the larvae react to the alarm secretion with a well organized group flight. Young adults can also react to the alarm substance by falling. The larval defensive secretion is a complex mixture of substances. The 2-hexenal contained in the secretion causes a larval unrest but no typical flight reaction.
    Notes: Zusammenfassung Weibchen und Jungtiere vonElasmucha grisea bilden eine Brutpflegegemeinschaft, in der das Muttertier seine Nachkommenschaft maximal bis zum vierten Larvenstadium beschützt. Der Zusammenhalt der Schutzgemeinschaft wird durch einen Spurstoff gewährleistet, den die Jungtiere beim Laufen auf die Unterlage abgeben. Sowohl Larven (mit Ausnahme des L 1 Stadiums) als auch die Mutterwanze können dieser Spur folgen. Eine gesichert wahrnehmbare Spur entsteht erst, wenn mehrer Larven hintereinander laufen (bei L 3 fünf Larven). Einer von 20 Larven (L 3+L 4) gelegten Spur konnten die Jungtiere noch nach einer halben Stunde sicherbar folgen. Das bei Bedrohung freiwerdende Wehrsekret von adulten und larvalen Wanzen hat zusätzlich Alarmfunktion. Es veranlaßt die brutpflegende Mutterwanze zum Angriff, d.h. zu gerichtetem Anlauf der Duftquelle und zu Flügelschwirren. Mit Ausnahme des L 1 Stadiums reagieren Jungwanzen auf das Wehrsekret mit geordneter Gruppenflucht. Junge Adultwanzen können sich bei Alarmsekretgabe fallen lassen. Das larvale Wehrsekret ist ein komplex zusammengesetztes Substanzgemisch. Das darin enthaltene 2-Hexenal löst bei Larven Unruhe aber keine typischen Fluchtreaktionen aus.
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    Insectes sociaux 26 (1979), S. 155-164 
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    Topics: Biology
    Description / Table of Contents: Resume Le fait d'enlever la reine entraîne le développement des ovaires des ouvrières chez le Frelon orientalVespa orientalis L., surtout dans les cinq jours suivants. Le refroidissement des ouvrières ou la fourniture à celles-ci d'un régime sans protéines inhibent leur développement ovarien, mais, dans les deux cas, l'inhibition disparait dès que ces conditions artificielles sont levées. Dans les groupes d'ouvrières, le developpement des ovaires apparait seulement chez les ouvrières du haut de la hiérarchie. Cependant, on l'observe chez toutes les ouvrières qui ont été isolées après qu'elles aient vécu en groupe. Par ailleurs, l'inhibition du développement ovarien se produit chez 50% environ des ouvrières qui ont été isolées depuis leur éclosion imaginale, ce qui suggère que les contacts sociaux stimulent de développement ovarien des ouvrières orphelines. Le développement ovarien a été aussi observé chez les ouvrières qu'on empêchait de construire: nous discutons la relation entre l'activité de construction et le développement ovarien.
    Notes: Summary Removal of the queen induced ovarial development in workers of the Oriental hornet,Vespa orientalis L. This occurred in workers kept in groups and mainly during the first five days after removal of the queen. Cooling of the workers or their subjection to a protein-free diet inhibited their ovarial development, but in either case, the inhibition disappeared once normal conditions were restored. For workers living in a group, ovarial development occurred only in workers of high hierarchal rank. However, the ovaries developed in all workers which were isolated singlyafter having lived in a group. On the other hand, inhibition of ovarial development occurred in about 50% of workers isolated singly from the moment of emergence, which suggests that social contact acts as a releasing stimulus for ovarial development in queenless hornet workers. Development of the ovaries was observed also in worker groups prevented from building, and the connection between building and ovarial development is discussed.
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    Insectes sociaux 26 (1979), S. 216-222 
    ISSN: 1420-9098
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    Topics: Biology
    Description / Table of Contents: Zusammenfassung Doronomyrmex pocahontas n.sp. wird beschrieben. Die neue Ameise sieht der europäischenDoronomyrmex pacis Kutter sehr ähnlich. Königinnen und geflügelte Jungweibchen wurden in 3 Völkern einerLeptothorax muscorum (Nyl.) nahestehenden Wirtsart gefunden. Locus typicus ist der Maligne Canyon bei Jasper, Alberta, Kanada. Die neue Art ist offenbar wieD. pacis ein arbeiterinloser, permanenter Sozialparasit. Männchen konnten nicht mit Sicherheit identifiziert und von den Männchen der Wirtsart unterschieden werden. Auch ist unbekannt, obD. pocahontas die Wirtsköniginnen tötet oder wieD. pacis mit ihnen zusammenlebt.
    Notes: Summary Doronomyrmex pocahontas n. sp. is described. The new ant closely resembles the European species,Doronomyrmex pacis Kutter. Queens and alate young females were found in 3 colonies of a host species which is or is closely related toLeptothorax muscorum (Nyl.). The type locality is Maligne Canyon, near Jasper, Alberta, Canada. The new species is an apparently workerless, permanent social parasite like its congener,D. pacis. No males could be identified or distinguished from host species males with certainty. WhetherD. pocahontas kills the host colony queens or lives alongside them (likeD. pacis) could not be decided.
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    ISSN: 1420-9098
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    Topics: Biology
    Description / Table of Contents: Summary The cycle of activity and diet ofBrachyponera senaarensis were studied in the rainy season (june 77) in order to compare them with observations onducted in a Sudan Savannah of the north eastern part of the Ivory Coast near Ferkessedougou. As in dry season, the cycle of activity is, in june, bimodal but the daily fluctuations appear to be more important and some workers of this typically diurnal species even try to hunt in the first half of the night. Ants hunting on the soil surface are, at that period, in a ratio of one to three compared to those collecting in the dry season. In same way, the surfaces of the prospected areas are smaller in the ratio of one to three. Between 20° and 44°C soil surface temperature, the abundance of seeds seems to exert a major influence on the local distribution of the above ground activities. In the rainy season, in the absence of seeds,Brachyponera acts as a predator of termites and small spiders. Thus, the species seems to be particularly well adapted to that climatically contrasted region.
    Notes: Resume Le cycle d'activité de récolte et le régime alimentaire deBrachyponera senaarensis (Ponerinae) ont été étudiés en saison des pluies (juin 1977) dans une savane de type soudanien près de Ferkéssédougou (Nord-Est de la Côte d'Ivoire). Ce cycle d'activité, typiquement bimodal, se déroule essentiellement de jour. Les fluctuations journalières peuvent être notables, provoquant le déplacement dans la soirée d'une partie de l'activité diurne. En saison des pluies l'espèce est, au total, moins active en surface qu'en saison sèche. La disponibilité en graines semble être le facteur exerçant l'influence la plus grande sur le déroulement du cycle. En l'absence de graines, l'espèce est prédatrice, son action s'exerçant surtout aux dépens des Termites et Araignées de petite taille.
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    Insectes sociaux 26 (1979), S. 273-278 
    ISSN: 1420-9098
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    Topics: Biology
    Description / Table of Contents: Resume Il y a deux théories différentes sur les mécanismes d'action de la substance royale de l'Abeille domestique (Apis mellifera) sur le développement ovarien des ouvrières. L'une de ces théories propose un mécanisme humoral direct, l'autre une modulation du système neuro-endocrinien par la chémoréception. Nous avons donné aux larves de Mélipones de l'acide 9-oxo-décène oïque, seul ou en association avec l'hormone juvénile, puis nous avons étudié l'effet éventuel de ces traitements sur la détermination des castes. Nous n'avons trouvé de modifications ni dans le pourcentage des reines par rapport aux ouvrières, ni dans la biométrie des caractères morphologiques. Nos résultats ne plaident donc pas en faveur d'un effet humoral de l'acide 9-oxo-décène oïque sur le déterminisme des castes chez les Mélipones. Ceci rend plus probable l'hypothèse d'un mécanisme neuro-endocrinien modulé par les organes des sens.
    Notes: Summary Two different theories exist concerning the way in which the honeybee “queen substance” affects the ovaries of worker honeybees. One theory involves a humoral mechanism, the other an indirect effect through the neuro-endocrine system after chemoperception. 9-Oxo-decenoic acid, one of the components of the “queen substance”, was administered to stingless bee larvae, alone or in combination with juvenile hormone. The effect of this treatment on caste determination was studied. Since no effect was found on the worker/queen ratio nor on morphometric characteristics, these experiments do not favour a humoral effect of 9-oxo-decenoic acid on stingless bee caste determination. This makes a sensory mechanism in the honeybee itself more probable.
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    Insectes sociaux 26 (1979), S. 322-342 
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    Topics: Biology
    Description / Table of Contents: Resume Les mécanismes d'acroissement du nid deNasutitermes costalis, ont été analysés par l'observation directe et par la photographie d'une colonie prospère, élevée au laboratoire pendant plus de 45 mois. Nous avons enregistré 52 périodes d'accroissement, chacune entraînant une augmentation de 10% du volume du nid. On peut diviser le processus d'accroissement du nid en 3 phases: la phase initiale, la phase de construction, la phase finale. La phase finale aboutit à une surface dont la forme traduit la convergence des premiers efforts de construction pendant la phase initiale d'accroissement. La construction est basée presque entièrement sur des répétitions multiples d'un petit nombre d'éléments architecturaux simples, essentiellement la division, d'un mur en deux embranchements et la réunion de murs voisins au moyen d'un pont. Tout cela se passe sur une “surface active” lisse qui demeure ainsi tout le temps de chaque période d'accroissement. Les intéressantes similitudes entre certains traits architecturaux de l'accroissement du nid deN. costalis, et certaines structures construites «de novo» par des groupes de termites avec une reine et appartenant à trois sous-familles de Termitidae suggèrent que le mode d'accroissement du nid deN. costalis est relativement primitif.
    Notes: Summary The nest expansion behavior ofNasutitermes costalis, a common Neotropical arboreal termite, was analyzed by means of direct and photographic observation of a thriving laboratory colony over a 45-month period. 52 expansion episodes were recorded, each resulting in the addition of as much as 10% to the nest volume. The expansion process can be divided into 3 phases Initiation, Building, and Termination. Termination results in a nest surface whose shape focuses initial building efforts during the Initiation of subsequent expansion. Building consists almost entirely of multiple repetitions of a few simple architectural elements — primarily the branching of one wall into two and the joining of neighboring walls via a bridge — all occurring on a smooth “active surface” which persist throughout each expansion episode. Interesting similarities between certainN. costalis nest expansion architectural features and structures builtde novo by queened termite groups from 3 subfamilies of the Termitidae suggest that this is a relatively primitive mode of nest expansion.
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    Insectes sociaux 26 (1979), S. 364-372 
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    Topics: Biology
    Description / Table of Contents: Zusammenfassung Die grössten Ameisenkolonien in der nordamerikanischen Sonora Wüste bildet die mexikanische BlattschneiderameiseAtta mexicana, deren Futtersammelaktivitäten erstmalig beschrieben werden. Zum Futtersammeln benutzen diese Ameisen ein System aus Tunneln und Strassen, das vom Nest zu der Vegetation führt. Die Hauptbeobachtungskolonie wurde während mehrerer Jahre in den Monaten Dezember, Januar, März und Juli/August insgesamt 24 Tage lang kontrolliert. Sie sammelte während dieser Zeit Pflanzenmaterial auf einer Grundfläche von etwa 8000 m2. Die Ameisen schnitten bevorzugt zwei annuale Pflanzenarten, nahmen aber, wen diese fehlten, auch mehrere Arten von perennierenden Pflanzen an. Zusätzlich zu frischen wurden auch trockene Pflazenteile eingetragen. Das Schneideverhalten der Ameisen war variabel und hing von Grösse und Form der Pflanzen ab. Die Ameisen sammelten in Winter und Frühling tagsüber und gingen im Sommer weitgehend zu nächtlicher Sammelaktivität über.
    Notes: Summary The largest ant colonies in the North American desert are produced by the Mexican leafcutting ant,Atta mexicana (F. Smith), in northern Sonora. The foraging behavior ofA. mexicana is described for the first time. The ants use a system of tunnels and trails extending outward from the nest to reach target vegetation. Over the combined study periods from 1974 to 19777, one colony collected material from a total surface area of about 8,000 m2. The ants selectively attacked two species of winter annual plants and repeatedly utilized four perennials, twoCercidium spp.,Sapium biloculare (S. Wats.), and Larrea tridentata Coville when the annuals were absent. In addition to fresh vegetation, they also collected dry material. The leafcutting behavior of the ants is variable, depending on the size and form of the plant material utilized. The ants foraged during the daytime in winter and spring but became largely nocturnal in summer.
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    Insectes sociaux 26 (1979), S. 373-381 
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    Topics: Biology
    Description / Table of Contents: Resume Nous décrivons le «timing» de l'élevage des reines et de l'essaimage après avoir enlevé la reine dans des colonies d'abeilles «africanisées». De nouvelles reines ont été élevées à partir de larves de moins de 3 jours; beaucoup de celles-ci et beucoup d'œufs ont été déplacés par les ouvrières dans des cellules de reines nouvellement construites. Le taux de mortalité les ouvrières dans des cellules de reines nouvellement ouvrières a été élevé, en moyenne de 50%, après l'orphelinage expérimental. A l'éclosion des nouvelles reines, 2/3 des colonies ont essaimé. Ces processus de remplacement de la reine et d'essaimage après la perte de celle-ci diffèrent de ceux des essaimages de reproduction par le manque de préparation avant la perte de la reine, un intervalle de temps sans rene plus long, et une absence de l'essaimage. Par ailleurs il n'y a pas de corrélation entre le nombre d'essaims et la surface occupée par le couvain operculé ou le nombre de cellules royales.
    Notes: Summary The timing of queen rearing and swarming are described after queens were removed from colonies of Africanized bees. New queens were reared from newly hatched to three day old worker larvae, many of which were moved in the egg or newly eclosed larval stages by workers into newly constructed queen cells. Mortality of worker eggs and larvae following dequeening was high, averaging 50%. When new queens emerged, swarms issued from two-thirds of the colonies. This process of queen replacement and queen-loss swarming differs from that of reproductive swarming in the lack of preparation before queen loss, longer queenless interval, lack of correlation between number of swarms and sealed brood area or number of queen cells, and lack of Congestion in colonies when swarms issued.
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    Insectes sociaux 22 (1975), S. 75-82 
    ISSN: 1420-9098
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    Topics: Biology
    Description / Table of Contents: Zusammenfassung Das Tragen und Freilassen von Männchen, Weibchen und Arbeiterinnen durch Arbeiterinnen vonAcromyrmex versicolor versicolor ist eine tägliche Tätigkeit, welche meistens nach Beendigung der Futtersuche stattfindet. «Ausgestossene» Ameisen, bei deren Mehrzahl es sich um Geschlechtstiere handelt, werden unversehrt in verschiedenen Abständen vom Nesteingang freigelassen. Die meisten der so ausgestossenen Ameisen kehren sofort zum Nest zurück, um anschließend erneut zurückgewiesen zu werden. Das Tragen von Ameisen kann als ein Mechanismus zur Verbreitung ebenso dienen, wie als eine Funktion, die Kolonie von belastenden Mitgliedern zu befreien. Dieses Verhalten könnte außerdem dazu dienen, nicht zur Kolonie gehörende Individuen zu eliminieren. Gegenwärtig sind die Hinweise auf diese drei Hypothesen allerdings einander widersprechend.
    Notes: Summary The carrying and release of males, females, and workers byA. v. versicolor workers from the nest is a daily activity that principally occurs after the colony stops foraging. Ejected ants, the majority of which are sexual forms, are released unharmed at various distances from the nest opening. Most expelled ants return directly to the nest only to be rejected again. Ant carrying may serve as a colony dispersal mechanism as well as functioning to rid the colony of those members that are heavy drains on colony resources. The behavior may also function to exclude noncolony members. Present évidence pertaining to all three hypotheses, is, however, conflicting.
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    Insectes sociaux 22 (1975), S. 117-134 
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    Topics: Biology
    Description / Table of Contents: Summary The authors studied approximately 80.000 ant workers of Formica rufa-group collected in the years 1961–1974 in various regions of Poland. A total number of 39 teratological changes (in 0.05% of all tested ants) were described. In view of the paucity of papers published on this subject it is not possible to draw general conclusions as to the causes of these teratological variations.
    Notes: Zusammenfassung Die Verfasser haben ungefähr 80 000 Ameisen-Arbeiterinnen aus der Formica rufa-Gruppe untersucht, welche in den Jahren 1961–1974 in verschiedenen Teilen von Polen gesammelt wurden. Insgesamt werden 39 teratologische Veränderungen beschrieben, was ungefähr 0,05% der gesamten geprüften Individuen entspricht. Bisher wurden sehr wenig Arbeiten über dieses Thema veröffentlicht, so daß die Verfasser keine weitergehenden Schlußfolgerungen über die Ursachen der teratologischen Veränderungen ziehen konnten.
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    ISSN: 1420-9098
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    Topics: Biology
    Description / Table of Contents: Summary 1. Total production of ♂♂ and ergatomorphs in one brood period of 58 colonies ofHarpagoxenus sublaevis collected in the open during hibernation (experiment a: 25 colonies, brood rearing in the beginning of hibernation, experiment b: 33 colonies, brood rearing in spring time after a compete natural hibernation) was investigated (Tab. Ia and Ib). 2. Sexually active («locksterzelnde») potential queens and sexually inactive «primary workers» can be distinguished among the workerlike ergatomorphs. 3. The sex ratio (♂♂/sexually active ergatomorphs) is near 1:1 (experiment b). 4. The rate of sexually active ergatomorphs (63,3% of all ergatomorphs produced in experiment b) is much higher than the percentage of queens (14,4%) in the female brood of the related free-livingLeptothorax acervorum. Sexually active ergatomorphs remaining unmated may return to their mother colonies as «secondary workers». 5. The production of ♂♂ and ergatomorphs as well as the rate of sexually active ergatomorphs grow with increasing numbers of slaves per colony, but by far not proportionally to it (Tab. II). 6. The production numbers vary from colony to colony in an extraordinarily wide range. Some factors presumably responsible to this variation are discussed.
    Notes: Zusammenfassung 1. Die Gesamproduktion an ♂♂ und Ergatomorphen in einer Brutaufzucht von 58 im Freiland während der Überwinterung gesammelten Völkern (Versuch a: 25 Völker, Aufzucht zu Beginn der Überwinterung, Versuch b: 33 Völker, Aufzucht im Frühjar nach einer kompletten natürlichen Überwinterung) des sklavenhaltendenHarpagoxenus sublaevis wurde ermittelt (Tab. Ia und Ib). 2. Unter den Ergatomorphen lassen sich sexuell aktive (»locksterzelnde«) potentielle Königinnen und sexuell inaktive primäre unterscheiden. 3. Das Geschlechterverhältnis (♂♂/sexuell aktive Ergatomorphe) liegt nahe 1/1 (Versuch b mit 33 Völkern). 4. Der Anteil sexuell aktiver unter den Ergatomorphen liegt mit 63,3% (Versuch b) wesentlich höher als der Anteil der Königinnen (14,4%) in der weiblichen Brut des verwandten selbständigenLeptothorax acervorum. Unbegattet bleibende sexuell aktive Ergatomorphe können jedoch als »sekundäre « in ihr Mutternest zurückkehren. 5. Die Produktion von ♂♂ und Ergatomorphen sowie der Anteil der sexuell aktiven Ergatomorphen nehmen mit wachsender Anzahl der Sklaven im Volk zu, jedoch bei weitem nicht proportional zu dieser (Tab. II). 6. Die Produktionswerte streuen von Volk zu Volk außerordentlich breit; einige dafür vermutlich verantwortliche Faktoren werden diskutiert.
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    Insectes sociaux 22 (1975), S. 243-267 
    ISSN: 1420-9098
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    Topics: Biology
    Description / Table of Contents: Summary The frontal gland of termites is a single tegumentary gland. In the soldiers of Rhinotermitidae it corresponds to an invagination which opens at the front of the head by the frontal pore or fontanelle. This gland is well developed and generally extends into a large part of the abdomen. Using scanning electron microscopy we state a more precise picture of the frontal weapon, which consists of the frontal gland, the pore and its associated cephalic structures (frons, clypeus and labrum) involved in the defensive system of the insect. Many isolated glandular pits occur on the labrum or around the frontal pore, forming in the latter case a punctured area. This morphological data is interpreted, as far as possible, from a functional point of view. These observations also permit us to extend the study of the phylogenetic relations within the Rhinotermitidae. The subfamilies are readily distinguishable, each having retained a group of primitive characters and developed a set of evolved characters. The Rhinotermitinae, with the exception of one genus,Prorhinotermes, possess a characteristic labral «daubing brush». They form a coherent group throughout which the gradual specialization of the frontal weapon can be traced. The genusProrhinotermes is therefore removed from the Rhinotermitinae the form a monotypic subfamily, Prorhinotermitinae (Subfam. nov.) characterised in the soldier caste by its oval head, toothless mandibles, small fontanelle, and lack of a labral brush.
    Notes: Résumé La glande frontale des termites est une glande tégumentaire impaire. Chez les soldats de Rhinotermitidae, elle forme une profonde invagination qui s'ouvre à l'avant de la tête par le pore frontal ou fontanelle. Cette glande est bien développée et s'étend généralement jusqu'à l'arrière du corps de l'insecte. A l'aide du microscope électronique à balayage, nous établissons une figuration plus précise de «l'arme frontale» constituée par l'ensemble de la glande frontale, du pore et des structures céphaliques (front, clypéus, labre) impliquées dans le fonctionnement défensif. De nombreux petits orifices glandulaires isolés répartis sur le labre ou à proximité du pore frontal, parfois rassemblés en une aire criblée, sont mis en évidence. Les données morphologiques obtenues sont interprétées autant que possible de façon fonctionnelle. Ces observations permettent égalment d'approfondir l'étude des relations phylogénétiques des Rhinotermitidae. Les diverses sous-familles apparaissent ainsi très nettement distinctes les unes des autres. Les représentants de chacune d'elles ont conservé un assortiment différent de caractères primitifs et développé un jeu différent de caractères évolués. Les Rhinotermitinae, à l'exception du genreProrhinotermes, possèdent une «brosse à enduire» labrale caractéristique et forment un ensemble cohérent au sein duquel on peut suivre les perfectionnements graduels de l'arme frontale. Nous avons détaché le genreProrhinotermes des Rhinotermitinae et l'avons inclus dans une sous-famille autonome, plus primitive, celle des Prorhinotermitinae (Subfam. nov.).
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    Insectes sociaux 22 (1975), S. 375-379 
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    Topics: Biology
    Description / Table of Contents: Zusammenfassung Die jahreszeitliche Variation der Körpergrösse der Arbeiterinnen vonLasioglossum (Dialictus)-Arten ist mit dem Grad der Sozialität (gesessen etwa an der Lebensdauer der Königinnen) korreliert, den die betreffenden Arten erreicht haben. Ein interspezifischer Vergleich der Grösse der Variation ergibt ein einfaches Mass der Sozialität der Arten. Verschiedene Muster der jahreszeitlichen Variation der Körpergrösse können unterschieden werden. In Arten mit niedriger Sozialität scheinen diese Muster von exogenen Faktoren, wie Temperatur und Tageslänge, kontrolliert zu werden, in sozial höheren Arten dagegen von endogenen (kolonieeigenen).
    Notes: Summary For species ofLasioglossum, subgenusDialictus, the amount of seasonal body size variation of worker bees is correlated with indicators of the level of sociability attained by the species, such as queen longevity. Interspecific comparison of the amount of variation gives a simple measure of the level of sociality of the species. Different patterns of seasonal body size variation can be controlled by factors such as temperature and day length which are exogenous to the colony but in species with higher levels of sociality these patterns may be controlled endogenously.
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    Description / Table of Contents: Summary Camponotus vividus is an arboricolous ant that forages primarily during daytime. Its hunting activity is highest around 6 a.m. and 5 p.m. The structure of the nest is polycalic and the colony numbers several thousands of ants. Workers forage within a hirizontal range of 30 to 40 meters from the nest and on the trees up to a height of about 60 meters. They usually perform this task in groups. The foraging area gradually moves around with time. Most variations of bioclimatic factors do not seem to exert any direct influence on the period of activity. These ants respond only to light when they start hunting, and they stop when it rains heavily on the foliage. An analysis of their made through collecting specimens brought to the nest indicates that about 80 % of the total food is of vegetable origin. They also tend Homoptera. The proteins in their diet is obtained through predation on insects. Comparisons with other local species of the genus indicate a good exploitation of the potentials of the conmunity: diets are complementary, peaks of activity are spread in time, and hunting areas never overlop.
    Notes: Résumé Camponotus vividus est une fourmi arboricole dont l'activité de prospection s'exerce de jour. Elle présente deux pics d'activité vers 6 heures et 17 heures. Le nid est polycalique et la société adulte compte plusieurs milliers d'individus. Les ouvrières chassent dans un rayon de 30 à 40 mètres autour des calies et montent jusque dans la canopée à 60 mètres du sol. Les produits d'origine végétale, principalement sous forme de gommes, représentent plus de 80 % de l'alimentation, le reste étant constitué d'insectes. Le comportement de chasse des diverses espèces deCamponotus favorise l'exploitation optimale des ressources du milieu par l'utilisation de régimes alimentaires complémentaires, unddécalage dans le temps des périodes d'activité maximale et une séparation spatiale des aires prospectées.
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    Insectes sociaux 23 (1976), S. 23-28 
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    Topics: Biology
    Description / Table of Contents: Résumé Nous avons mesuré les taux de glucose d'homogénats de couvain d'Abeilles (du 5e au 16e jour de vie larvaire) et de la gelée royale distribuée à chaque caste (du 5e et 9e jour de vie larvaire). La majorité des jours où les mesures furent réalisées, le taux de glucose des larves d'ouvrières s'éleva jusqu'à deux fois celui des larves de reine. Les changements les plus marqués dans les taux de glucose furent obtenus du 5e au 8e jour de vie larvaire. Durant cette période, l'augmentation des taux de glucose fut parallèle dans les homogénats de larves d'ouvrières et dans la gelée dont elles se nourrissaient. Rien de tel ne fut observé dans les homogénats de couvain de reine.
    Notes: Summary The glucose levels in homogenates of heneybee brood (5th–16th day of life) and in the jelly of each caste (5th–9th day of life) were determined. The glucose level of workers was, during the majority of days tested, up to twice as high as in queens, the most impressive changes in the glucose level occurred during the 5th–8th days of life, at which time there was a parallel rise in the glucose levels of worker homogenate and of the jelly which serves as their food. No such rise was observed in queen brood homogenate.
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    Insectes sociaux 25 (1978), S. 53-62 
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    Description / Table of Contents: Zusammenfassung In einigen Arten vonDrepanotermes zeigen die Arbeiter eine altersabhängige Arbeitsteilung in bezug auf Reparaturen am Nest und Sammelaktivität. Sofort nach der Beschädigung eines Nestes nahm die Anzahl der Arbeiterstadien A1, A2 und A3 ab, während die Arbeiterstadien A4+A5 und die Soldaten häufiger anzutreffen waren. Dies traf fürD. rubriceps als auch fürD. perniger zu. A4+A5 führten den grössten Anteil der Nestreparaturen aus, und zumindestens inD. perniger war die Anzahl dieses Arbeiterstadiums noch 60 Stunden nach der Beschädigung signifikant höher als in unbeschädigten Teilen des Nestes. An den oberirdisch sammelnden Termitengruppen waren inD. perniger über 75% Arbeiter des Stadiums A4+A5 beteiligt. Die Häufigkeit der jüngeren Stadien nahm stark mit absteigendem Alter ab. Soldaten waren ebenfalls überdurchschnittlich in den Sammelgruppen vertreten. In den peripheren Gallerien waren A4+A5 nicht unbedingt häufiger anzutreffen als im Inneren des Nestes, obwohl sie in den Sammelgruppen deutlich überwogen.
    Notes: Summary Species ofDrepanotermes show instar-dependent behavioural differences in the worker caste in both nest repair and foraging activity. Immediately following damage to the nest, the frequencies of W1, W2 and W3 at the damaged site decreased, while those of W4+W5 and soldiers increased in bothD. rubriceps andD. perniger. W4+W5 carried out most of the nest repair, and, at least inD. perniger, their frequency was still significantly higher at the damaged site 60 hours after damage. InD. perniger more than 75% of termites in the above-ground foraging parties were W4+W5, and the frequencies of younger workers were related to instar, the earlier the instar the lower the frequency. Soldiers were also over-represented in foraging parties. W4+W5 were not necessarily more abundant in the peripheral galleries than they were in the central nest, despite their predominance in the foraging parties.
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    Insectes sociaux 25 (1978), S. 339-350 
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    Topics: Biology
    Description / Table of Contents: Zusammenfassung Die europäische, sklavenhaltende AmeiseHarpagoxenus sublaevis weist einen speziellen Polymorphismus im weiblichen Geschlecht auf: Neben normalen Arbeiterinnen kommen zwei Formen von Königinnen vor, das normale, jedoch sehr seltene, geflügelte Weibchen und das viel häufigere arbeiterinähnliche, sogenannte ergatoide Weibchen. Für die Entwicklung von Larven entweder zu ergatoiden oder zu geflügelten Weibchen ist ein genetischer Mechanismus verantwortlich. Wir sammelten 61 Völker des nahe verwandten, nordamerikanischenHarpagoxenus canadensis an verschiedenen Orten in Ontario und Quebec, Kanada, und sezierten daraus insgesamt 241 Arbeiterinnen, 30 Intermorphe und 26 entflügelte Weibchen um festzustellen, ob ein ähnlicher Polymorphismus auch bei dieser Art vorliegt.H. canadensis hat jedoch einen recht normalen Polymorphismus. Alle Königinnen, die wir fanden, waren entflügelte Weibchen. Das receptaculum seminis, das den einzig bedeutsamen Unterschied zwischen ergatoiden Weibchen und Arbeiterinnen vonH. sublaevis darstellt, fehlt allen Arbeiterinnen und Intermorphen vonH. canadensis. Weitere Ergebnisse unserer Untersuchung sind folgende:H. canadensis ist, wieH. sublaevis, monogyn. In wenigen Kolonien legen einige Arbeiterinnen und Intermorphe Eier, auch in weiserlrichtigen Völkern. Die durchschnittliche Ovariolenzahl ist beiH. canadensis-Arbeiterinnen wesentlich geringer als beiH. sublaevis, variiert bei beiden Arten jedoch in etwa demselben Ausmß (table IV);H. canadensis-Arbeiterinnen sind darin den Arbeiterinnen der Wirtsarten ähnlicher. Die Anzahl der Malpighigefäße beträgt 5 bei Weibchen und Arbeiterinnen. Die Giftdrüse hat bei beidenHarpagoxenus-Arten etwa dieselbe Größe. Dagegen ist beiH. canadensis die Dufour-Drüse erheblich kleiner als beiH. sublaevis. H. canadensis ist damit in einer Reihe von Merkmalen der gemeinsamen WirtsgattungLeptothorax (S. G.Mychothorax) ähnlicher alsH. sublaevis.
    Notes: Summary The European slave-making antHarpagoxenus sublaevis has an unusual female polymorphism. In addition to ordinary workers, there are two kinds of reproductive females, the very rare full queens and the much more common ergatoid (i. e. workerlike) queens. A genetic mechanism is responsible for the development of larvae into either ergatoid or full queens. Sixty-one colonies of the closely related North American speciesHarpagotenus canadensis were collected from several localities in the provinces of Ontario and Quebec, Canada, and a total of 241 workers, 30 intermorphs, and 26 dealate full queens were dissected in order to discover whether a similar polymorphism occurs in this species. However,H. canadensis was found to have an essentialy normal polymorphism. All the fecundated reproductive females that we found were dealate full queens. A spermatheca, which constitutes the only significant difference between ergatoid queens and workers inH. sublaevis, is absent in all workers and intermorphs ofH. canadensis. In addition, we found that colonies ofH. canadensis are monogynous (likeH. sublaevis). However, minority of workers and intermorphs lay eggs even in queenright colonies. The average number of ovarioles is much lower inH. canadansis workers than in those ofH. sublaevis; but, in both species, it varies over about the same range (table IV). In this respect,H. canadensis workers resemble more closely the workers of the host species. The number of Malpighian tubules is five in both the reproductive females and workers. The poison gland is about the same size in bothHarpagoxenus species, but the Dufour's gland inH. canadensis is considerably smaller than inH. sublaevis. Thus, in several respects,H. canadensis bears a closer resemblance to the common host genusLeptothorax (subgenusMychothorax) thanH. sublaevis does.
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    Pure and applied geophysics 113 (1975), S. 87-95 
    ISSN: 1420-9136
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    Topics: Geosciences , Physics
    Notes: Summary In the northern and central sections of the San Andreas Fault Zone, and along Calaveras and Hayward faults, clay gouges have been found to occur on the surface and at shallow depths. It is consistent with the available geochemical data that such gouges can exist at depths down to 10 km. If extensive gouge materials exist in a fault zone then their properties will determine, to a large extent, the behavior of the fault. From known properties of clays in the presence of water we can infer that, in such cases, the tectonic stress and the stress drops for earthquakes will be low and substantial creep will take place before earthquakes.
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    Pure and applied geophysics 113 (1975), S. 107-118 
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    Notes: Summary The relation between remanent magnetization and volumetric strain for gabbro samples stressed in uniaxial compression inside a near zero-field μ-metal shield has been examined. For samples with an induced IRM parallel to the axis of compression, remanent magnetization decreased linearly up to the onset of dilatancy. As increased stress produced additional dilatancy, the variation of remanent magnetization became nonlinear, and the stress dependence continually decreased until the rock failed. Stress cycling with the peak stress augmented for each cycle produced a continuous decrease in the zero stress value of the IRM although an appreciable amount of recovery was observed during unloading. When the sample was loaded in constant stress increments after the onset of dilatancy and held for several minutes at each level, time-dependent variations in remanent magnetization coincided with time-dependent increases in inelastic volumetric strain. In general as the inelastic creep rate increases, the rate of change in remanent magnetization increases. These results suggest that dilatancy related effects of the intensity of rock magnetization should be observed in magnetic rocks in epicentral regions prior to earthquakes and may serve as both long- and short-term precursors.
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    Pure and applied geophysics 113 (1975), S. 97-106 
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    Notes: Summary Deformation causes changes in gravity even though the measuring station is fixed relative to the center of the earth and the total mass in the vicinity of the station does not change. Deformation has two effects: the density at a point changes in response to changes in local stresses and the point itself moves relative to the station. The general expression derived here shows that the gravity change depends on the uplift immediately beneath the station and the deformation of cavities at depth — cracks, pores, magma reservoirs, etc. The approximation is made that density is uniform except for cavities, but no assumptions about the constitutive behavior of the medium are necessary. The gravity change studied here shows interesting analogies with the gravity effect due to buried bodies with anomalous density. For example, I find that the net volume change due to deformation can be found by integrating the gravity anomaly over the earth's surface, in analogy with the calculations for excess mass. The theory is especially useful when both deformation and net fluid flow into or out of the system occurs. The results are applied to uplift and gravity changes observed during the great Alaskan earthquake, the Matsushiro earthquake swarm, and a draw-down operation at the Wairakei geothermal field. The data at Wairakei are used to estimate the net amount of water taken from the aquifer. The data at Matsushiro is not sufficiently precise to discriminate between the various mechanisms that have been proposed, but the Alaskan earthquake data suggest that no dilatancy or fluid flow occurred between the survey in 1962 and the resurvey in 1964 just after the event.
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    Pure and applied geophysics 113 (1975), S. 141-147 
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    Notes: Summary A physical interpretation of empirical formulas for earthquake magnitude (M) and spatial extents of land deformation and aftershock area is attempted on the basis of a dilatancy model. It is demonstrated that the precursor time interval (τ) vs.M relation approximately fits in that for the τ vs. typical length of earthquake zone provided the above formulas hold good. A diffusion process in a dilatant region seems also to account for these approximate formulas.
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    Pure and applied geophysics 113 (1975), S. 169-181 
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    Notes: Summary Similar precursory phenomena have been observed before earthquakes in the United States, the Soviet Union, Japan, and China. Two quite different physical models are used to explain these phenomena. According to a model developed by US seismologists, the so-called dilatancy diffusion model, the earthquake occurs near maximum stress, following a period of dilatant crack expansion. Diffusion of water in and out of the dilatant volume is required to explain the recovery of seismic velocity before the earthquake. According to a model developed by Soviet scientists growth of cracks is also involved but diffusion of water in and out of the focal region is not required. With this model, the earthquake is assumed to occur during a period of falling stress and recovery of velocity here is due to crack closure as stress relaxes. In general, the dilatancy diffusion model gives a peaked precursor form, whereas the dry model gives a bay form, in which recovery is well under way before the earthquake. A number of field observations should help to distinguish between the two models: study of post-earthquake recovery, time variation of stress and pore pressure in the focal region, the occurrence of pre-existing faults, and any changes in direction of precursory phenomena during the anomalous period.
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    Pure and applied geophysics 113 (1975), S. 69-86 
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    Notes: Summary Three types of triaxial compression experiments are used to characterize the frictional processes during sliding on quartz gouge. They are: 1) pre-cut Tennessee Sandstone sliding on an artificial layer of quartz gouge; 2) fractured Coconino Sandstone sliding along experimentally produced shear fractures; and 3) a fine-grained quartz aggregate deformed in compression. The specimens were deformed to 2.0 kb confining pressure at room temperature and displacement rates from 10−2 to 10−5 cm/sec dry and with water. There is a transition in sliding mode from stick-slip at confining pressures〈0.7 kb to stable sliding at〉0.7 kb. This transition is accompanied by a change from sliding at the sandstone-gouge contact (stick-slip) to riding on a layer of cataclastically flowing gouge (stable sliding). Quartz gouge between the pre-cut surfaces of Tennessee Sandstone lowers both the kinetic coefficient of friction and the magnitude of the stick-slip stress drops compared to those for a pre-cut surface alone. Stick-slip stress drops are preceded by stable sliding at displacements of 10−5 cm/sec. For a decrease in displacement rate between 10−3 and 10−5 cm/sec, stress-drops magnitudes increase from 25 to 50 bars. Tests on saturated quartz gouge show sufficient permeability to permit fluidpressure equilibrium within compacted gouge in 10 to 30 seconds; thus the principle of effective stress should hold for the fault zone with quartz gouge. Our results suggest that at effective confining pressures of less than 2.0 kb, if a fault zone contains quartz gouge, laboratory-type stick-slip can be an earthquake-source mechanism only if a planar sliding-surface develops, and then only when the effective confining pressure is less than 0.7 kb.
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    Pure and applied geophysics 113 (1975), S. 119-125 
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    Notes: Summary Opening of cracks before an earthquake (dilatancy) causes inelastic crustal uplift. Raising the pore pressure in these cracks as pore fluid diffuses into the dilatant zone produces further elastic uplift. Since the time between resaturation of the dilatant zone and the earthquake is shorter than the life of thev p /v s anomaly, the elastic uplift is less than the inelastic. The magnitude of thev p /v s anomaly gives a lower bound on the compressibility of the dilatant zone. Velocity and uplift measurements lead to the conclusion that if dilatancy occurred before the 1971 San Fernando earthquake, the pore pressure in the hypocentral region at the time of the event must have been at least an order of magnitude below hydrostatic.
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    Notes: Summary A radiative-conductive model is constructed to study short-term effects of various carbon dioxide concentrations on the atmospheric boundary layer for different seasons. The distribution of the exchange coefficient is modeled with the aid of the KEYPS formula. Infrared radiation calculations are carried out by means of the emissivity method and by assuming that water vapor and carbon dioxide are the only radiatively active gases. Global radiation is computed by specification of Linke's turbidity factor. It is found that doubling the carbon dioxide concentration increases the temperature near the ground by approximately one-half of one degree if clouds are absent. A sevenfold increase of the present normal carbon dioxide concentration increases the temperature near the ground by approximately one degree. Temperature profiles resulting from presently observed carbon dioxide concentration and convective cloudiness of 50% or less are compared with those resulting from doubled carbon dioxide concentrations and the same amounts of cloud cover. Again, it is found that a doubling of carbon dioxide increases the temperature in the lower boundary layer by about one-half of one degree. The present results are obtained on the basis of fixed temperature boundary conditions as contrasted to the study ofManabe andWetherald (1967). Howeve, the conclusions are not addressed to global climate change, but to the distribution of the temperature of the air layer near the ground.
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    Pure and applied geophysics 113 (1975), S. 419-433 
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    Notes: Summary Geophysical survey data represent a class of information currently subjected to computer contouring techniques. The gridded network is a feature inherent to a large portion of these surveys. Taking advantage of this feature, a simple and highly efficient computer program has been developed, minimizing the contouring effort in terms of the money, time and programming involved in the interpretation process. The program includes interpolation between data points in two directions, determination of contour line coordinates, and subsequent plotting.
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    Pure and applied geophysics 113 (1975), S. 183-196 
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    Notes: Summary A dilatancy model is presented which seems capable of simulating the results of laboratory tests on rock samples. The fundamental assumption incorporated in the model is that dilatancy is caused by the opening of cracks, where the cracks open in the least compressive stress direction (Brace et al., 1966). Its simplicity and compatibility with numerical techniques, involving the simulation of both static and dynamic stress fields, permits prediction of dilatancy induced effects for stress states and loading conditions which are not experimentally attainable.
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    Pure and applied geophysics 113 (1975), S. 219-227 
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    Notes: Summary More than 20 coseismic resistivity steps were observed by a resistivity variometer at a station about 60 km south of Tokyo during a six-year period of observation. The logarithmic magnitude of steps normalized to an epicentral distance (δ) of 100 km is linearly correlated to earthquake magnitude (M). The larger the earthquake magnitude is, the longer is the time required for completing a resistivity step. Earthquakes, that produced a step, as plotted on anM-δ graph are clearly separated by a straight line $$M = - 12.5 + 2.5\log _{10} \Delta $$ from those that did not produce a step, δ being measured in units of km. The straight line is approximately equivalent to a resolution of strain steps of the order of 10−9. As the smallest rate of resistivity change that can be observed by the variometer is 10−5 or so, it is apparent that mechanical strain is amplified by a factor of 104 or thereabouts when it is measured in terms of resistivity change. Some of the steps are preceded by a premonitory effect. When long-period changes, mostly due to tidal loadings, are eliminated by a numerical filtration technique, precursors are brought out very clearly in a number of cases. The precursor time ranges from 1 to 7 hours and appears to be independent of magnitude.
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    Pure and applied geophysics 113 (1975), S. 735-746 
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    Notes: Abstract High resolution 3-cm weather radar was used to observe the three dimensional structure of a weak echo region of a severe convective storm in northern Minnesota, U.S.A. Observations show that a seemingly steady-state updraft in the lower portion of the storm broke into an unsteady structure in the upper levels. This is interpreted as indicating that precipitation loading gradually decelerated the upper reaches of the updraft, resulting in periodic breakout of a new updraft core on the inflow side. This periodic behavior of the updraft may be related to hailstreaks and what has been termed the multi-celled storm.
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    Pure and applied geophysics 113 (1975), S. 281-292 
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    Notes: Summary Teleseismic arrivals for large earthquakes occurring in the Circum-Pacific seismic source regions have been analysed forP-velocity variations prior to the February 24, 1972, Bear Valley earthquake at several stations in the vicinity of Bear Valley, California. The teleseismic arrivals have been analysed by the method of two-station residuals and corrected for observed azimuthal variations. The data covers the time period of July, 1971, through April, 1972, and suggests that during part of January, 1972, aP-velocity anomaly occurred beneath station BVL 2 km from the epicenter of the magnitude 5.1 Bear Valley event. A maximum vertical travel time delay of 0.15 seconds is observed. No other anomalous behavior associated with this event is suggested by the data for the other stations ranging from 7 to 19 km from the event's epicenter. These results support an anomalous zone of limited size with a maximum horizontal extent of less than 5 km perpendicular and about 10 km parallel to the San Andreas fault relative to the epicenter and confined within a 5 to 10 km portion of the uppermost crust. Also aP-velocity delay for waves travelling essentially along the intermediate stress axis would imply in this case that theP-velocity anomaly is caused by a bulk modulus mechanism such as that proposed by the dilatancy-fluid flow theory.
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    Pure and applied geophysics 113 (1975), S. 293-296 
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    Notes: Summary Quarry blasts provide an excellent source of waves with which to study temporal variations of seismic travel times. Using sources from several active quarries we found no time changes at Gold Hill (GHC), California from 7 months before the 1966 Parkfield mainshock to at least 13 months following the event. GHC is within 0.5 km of the zone of ground breakage associated with the earthquake. This event was one of the largest to occur in central California since 1906. The negative result of our experiment does not rule out the existence of an anomaly prior to the event, rather it emphasizes the difficulty of detecting such anomalies without a fortuitous combination of sources and stations. The routine monitoring of temporal changes in seismic velocity along the San Andreas fault may require not only dense networks of high quality seismic stations, but also sources whose spatial location and origin time can be controlled.
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    Pure and applied geophysics 113 (1975), S. 311-320 
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    Notes: Summary As a part of the Japanese earthquake prediction programme, deep borehole observation of the earth's crustal activities has been planned in and around Tokyo by the National Research Center for Disaster Prevention. The first place selected was in the city of Iwatsuki, about 30 km from the centre of Tokyo. Starting in 1970, the main construction was completed at the end of 1973. The tentative observation of micro-earthquakes and crustal movement by tiltmeters has been carried out since May, 1973. As expected, noise at the bottom of the hole (3500 m depth) is extremely small, about 1/1000–1/300 of that at the surface. We could, possibly, detect earthquakes with magnitudes greater than 2.0 within 50 km radius from the Iwatsuki observatory.
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    Pure and applied geophysics 113 (1975), S. 355-364 
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    Notes: Summary Lunar barometric tidal determinations (L 2) have been made by the Chapman-Miller method for Zürich (493 m) and Säntis (2000 m) based on 49 years' data. The seasonal variations ofL 2 are much larger at Zürich than on the Säntis summit. However, a comparison with the five other pairs of stations for which tidal determinations at different altitudes, but short horizontal distances, are available do not indicate that this result is as an altitude effect, nor do they show any other systematic differences betweenL 2 at the lower and the higher station. The solar tidal determinations agree well with those made byEggenberger (1944) and fit in with those obtained for other stations. From the difference between the pressure oscillations at Zürich and on Säntis the corresponding meantemperature oscillations of the air column between the two stations has been computed.
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    Pure and applied geophysics 113 (1975), S. 389-402 
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    Notes: Summary New measurements on the stratospheric distribution of H2, CH4, CO and N2O are presented and used to demonstrate the natural variability of the trace gas concentrations. The present CH4 and H2 measurements and data from older balloon flights are combined to give average vertical profiles. These profiles are compared with water vapor data from various authors to see if the vertical decrease in CH4 is matched by a corresponding increase in H2O. By comparing the average measured profiles to those predicted by a one-dimensional chemical model, profiles of the vertical eddy diffusion coefficientk z are deduced. Generally, a barrier in the low stratosphere and increasing transport in middle and upper stratosphere seem required to match theoretical and experimental profiles. The limitations of the calculatedk z are discussed.
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    Pure and applied geophysics 113 (1975), S. 461-466 
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    Notes: Summary A migration pattern is found for epicenters of the largest earthquakes which occurred between 1918 and 1964 inclusive. The pattern indicates that for three consecutive earthquakes which occurred at a predetermined distance of each other in a seismic belt, the third earthquake tends to be located close to the first one, and not away from it. The hypothesis that the reverse migration pattern is not true, can be accepted at statistical significance levels of only 5% or lower. A tectonophysical explanation of the pattern is proposed.
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    Pure and applied geophysics 114 (1976), S. 425-433 
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    Notes: Summary We propose a method that may be used to determine the spatial orientation of the fracture plane developed during hydraulic fracture. In the method, magnetic particles are injected into the crack with the fracturing fluid so as to generate a sheet of magnetized material. Since the magnetization of a body with extreme dimension ratios, such as a crack, exceeds that of an equidimensional body and since this magnetization is sensitive both to orientation and geometry, this could be used to obtain information about the crack. By measuring the vertical and horizontal components of the magnetic field and field gradients at the earth's surface surrounding the injection well with superconducting magnetometers having 10−4 gamma sensitivity and also by measuring field direction within the well itself, it should be possible to calculate the orientation and perhaps infer the approximate geometry of the fracture surface. Experiments on electric field potential operated in conjunction with this experiment could further constrain estimates of shape and orientation.
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    Pure and applied geophysics 114 (1976), S. 461-467 
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    Notes: Summary The relative detection capability of nine seismological stations situated north of 20°N in India has been studied. The best stations were the WWSSN stations NDI and SHL, followed by CHA, DDI, BOK and BHK. The remaining stations CAL, SEH and TOC are inferior in their detection capability.
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    Notes: Abstract Based on the average variability of the skewness with respect to the droplet mode radius, a wide set of mean size-distribution models is presented in terms of the modified gamma function for fog and stratified cloud droplets. These models appear appropriate for giving reliable size-distribution curves relative to the various formation stages of the droplet population both in fogs and in stratus and stratocumulus clouds. The corresponding volume extinction coefficient has been computed at various wavelengths from 0.4 to 17 μm using Van de Hulst's (1957) approximation multiplied by Deirmendjian's (1960) correction factors. This set of theoretical extinction data has been compared with experimental extinction measurements performed in atmospheres characterized by a marked thermal inversion for describing the evolutionary features of the water droplet size distribution within the whole ground layer.
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    Pure and applied geophysics 114 (1976), S. 479-494 
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    Notes: Summary Recently determined gravity anomalies along the NW-SE oriented Swiss Geotraverse from Basel to Bellinzona are used in combination with seismic refraction data to deduce a crustal section across the Swiss Alps. Topographic, Bouguer, free air, isostatic and geological corrections were applied to the data. Geological features considered in the corrections are the Swiss Molasse basin filled with sediments and the Ivrea body of high-density material. The resultant Bouguer anomaly over the Gotthard massif is 130 mgal lower than the Bouguer anomaly at the northern end of the profile near Basel. The Alpine region is associated with negative isostatic anomalies down to −20 mgal. The crustal thickness is found to increase gradually from the northern end of the profile (thicknessH=30 km) towards the Helvetic nappes at the northern margin of the Alps (H=38 km) and more rapidly towards the Gotthard massif (H=50 km) and further south to Biasca down to a depth of 58 km. From Biasca southward the crustal thickness thins quite rapidly to reach a depth of 30 km at the southern end of the profile near Bellinzona. Thus the Alps have a distinct asymmetric crustal root whose maximum thickness is almost twice the average crustal thickness in Central Europe. With the Mohorovičić-discontinuity deduced from seismic observations an average constant density contrast of −0.33 gcm−3 is found between the lower crust and upper mantle underneath the Alps.
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    Pure and applied geophysics 114 (1976), S. 61-69 
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    Notes: Summary Six Younger Granite localities showing normal and reverse magnetizations in equal proportion have given a Jurassic palaeomagnetic pole position ϕ=62.5°N, Λ=241.6°E; (Fisher's precision parameter (k)=27.8 and α95=13°). Individual palaeopole-positions have also been obtained for a Cretaceous pyroclastic rock and for two Pleistocene basalt flows.
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    Pure and applied geophysics 114 (1976), S. 95-107 
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    Notes: Summary Body force equivalents can be computed for subsidence of the Po delta in the twentieth century. Their preferred location suggests that not all of the subsidence is caused by pumping of fluids or other processes occurring at shallow depths. Some of the deformation may be due to crustal response to a north-south compressive stress.
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    Pure and applied geophysics 114 (1976), S. 158-158 
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    Pure and applied geophysics 114 (1976), S. 163-164 
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    Pure and applied geophysics 114 (1976), S. 119-139 
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    Notes: Abstract A theory of deep earthquakes, termed the inclusion collapse theory, is proposed in this paper. In the inclusion theory of crustal (or shallow) earthquakes, faults were shown to terminate within an inclusion zone. This zone represents a region within the brittle portion of the lithospheric plate that contains open cracks (voids) of varying sizes that, to a first order approximation, are uniformly distributed throughout the inclusion zone. When the lithospheric plate containing these faults and their associated inclusions is subducted into the mantle, the stress normal to the fault planes must increase. A depth is eventually reached where slippage along the fault planes is no longer possible. Earthquakes are postulated to occur at a specified depth within the mantle as a result of processes leading to collapse of these voids. When the long-term modulus of the plate is much greater than the long-term modulus of the mantle, large pressures are shown to develop within the plate during periods of active subduction. These pressures are shown to be sufficient to initiate partial collapse of voids of similar geometry throughout the inclusion zone. The inclusion collapse theory and the concentration of pressure within the plate lead to four results. (1) Earthquakes that are produced by a void collapse mechanism will not occur below a subduction depth calculated to be between 350 and 1000 km (2) The physical process most likely responsible for producing void collapse is the formation of shear, melt zones whose thicknesses are on the order of 1 to 10 cm in the immediate vicinity of the voids. This mechanism, is shown to produce a ‘precursor’ time on the order of a few hundred seconds during which there is a release of shear strain prior to the earthquake. (3) The maximum energy released by void collapse is independent of the source depth. (4) The number of earthquakes produced by this process will decrease hyperbolically with source depth. Source depth, in the context used in this article, refers to the depth in the mantle to the inclusion zone where voids of similar geometry are undergoing partial collapse. The maximum source depth refers to the depth where all voids have closed.
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    Pure and applied geophysics 113 (1975), S. 577-581 
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    Notes: Summary The determination of the residual circulation is essential to the interpretation of the sedimentation pattern. The classical picture of the residual circulation in the Southern Bight could not explain the observation of mud deposition in front of the Belgian coast. Hence, a more refined model was built where, although the shear and the Reynolds stresses are approximated by dispersion terms, the tidal stress was explicitly calculated using a preliminary tidal model. It is shown that the new model predicts the existence of a residual gyre off the Belgian coast which, increasing the residence time of the water masses and in particular the entrained water from the Scheldt estuary, fully explains the observed sedimentation pattern.
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    Pure and applied geophysics 114 (1976), S. 195-206 
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    Notes: Summary Measurements of bulk magnetic properties, including the natural remanent magnetization (NRM), susceptibility and the Königsberger ratio, on over 250 samples of Tertiary basalts from Disko and Nûgssuaq, West Greenland are reported. The NRM intensities in basalts (geometric mean value 3.3 A/m in SI units) were on average three to four times as large as the induced magnetization intensities. The susceptibilities (geometric mean value 2.1×10−2 SI units) were much more uniform than the NRM intensities. In the majority of samples, the NRM was predominantly of reverse (R) polarity, but samples from a few sites showed a remanence of normal (N) polarity. The NRM of both polarity classes (N, R) was very stable against alternating field (AF) demagnetization with median destructive fields of the order of 20,000–30,000 A/m (250–350 Oe), comparable to those for many stable continental and oceanic basalts. The viscous remanence intensity, as studied by storage tests on some specimens, was found to be an insignificant fraction of the original NRM, except in few cases. The low field hysteresis loops (Rayleigh loops) were studied for some specimens. A qualitative association was noted between wide hysteresis loop and relatively low AF stability, but no correlation was apparent between the loop type and the Königsberger ratio (Q n) of a specimen.
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    Pure and applied geophysics 114 (1976), S. 251-262 
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    Notes: Summary Since 1945 in Poland density measurements have been completed on drilling samples to obtain data for reduction and interpretation of geophysical results. In this paper the developments in density measurements techniques and data processing in Poland are reviewed. Mean density maps have been constructed for the following Pre-Devonian divisions: Volhynian, Valdai and Subholmian Cambrian, Holmian and Protoolenus Cambrian, Middle Cambrian, Lower Ordovician, Middle Ordovician, Upper Ordovician, Lower Silurian, Middle Silurian, Upper Silurian. On the basis of the same data the dependence of mean densities on the present depth of all the above divisions has been examined. This dependence has been approximated by regression equations of the following type: σ(h)= ah + b , σ(h) = ah2 + bh + c, σ(h)= alnh + b(σ(h): mean density,h: present depth). In addition to the coefficients of these equations the correlation coefficient, regression standard error, and confidence intervals have been calculated. Analysis of the results obtained revealed a dominant effect of compaction on the mean density values. Hypotheses have been presented concerning other geological factors responsible for the variation of these values. Regression curves constructed for the individual stratigraphic horizons served to estimate the maximum earlier depth of the Palaeozoic rocks of the Holy Cross Mountains and their vertical displacement. Similar studies have been completed for two adjacent boreholes situated in the Bug River depression. Their results indicate that mean density values can readily serve to estimate the amount of vertical tectonic displacement.
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    Pure and applied geophysics 114 (1976), S. 285-286 
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    Notes: Summary It is argued that normally the stresses in the lithosphere are hydrostatic or pseudohydrostatic. Several mechanisms are discussed that account for this feature, the more important one being plastic deformation leading to a situation in which the crustal material can be considered as ‘pre-stressed’ inthe horizontal plane. The proposed stress distribution has consequences for crustal model studies, especially when ductile flow is involved.
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    Notes: Summary A comparison is made between the multimode Rayleigh wave response to strike-slip fault motion in earth models with and without a low-velocity channel in the upper mantle. On the basis of this and previous studies it is concluded that for any focal mechanism the higher-mode amplitude spectra are useful for discriminating between the two types of structures.
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    Pure and applied geophysics 113 (1975), S. 257-280 
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    Notes: Summary About twenty blasts are used to determine crustal structure and to monitor temporal seismic velocity changes in southern California. The shot time is determined up to 10 msec by using a disposable pick-up placed directly on the explosive. About 17 permanent stations and 20 temporary stations are used for the recordings. With a fast paper speed (typically 1 cm/sec) and the WWVB radio signals superposed on the seismic trace, absolute timing accuracy of up to 10 msec is achieved. A representative structure thus determined consists of a 4 km thick 5.5 km/sec layer underlain successively by 23.4 km thick 6.3 km/sec layer, 5.0 km thick 6.8 km/sec layer and 7.8 km/sec half space. The details of the lower crust are somewhat uncertain. This structure can explain the travel time data, corrected for the station and source elevations and for the station delays, to ±0.15 sec. Small but systematic temporal velocity changes up to 3% have been found for some of the profiles. If the effect of the migration of the shot point is small enough, these changes are larger than experimental errors and represent real temporal change in the material property between the shot point and the stations.
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    Pure and applied geophysics 113 (1975), S. 673-682 
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    Notes: Summary Records from Swedish seismograph stations of underwater explosions in northern Scandinavia on 1 and 3 August, 1972-the so-called ‘Blue Road’ experiment-are used to calculate the average structure of an assumed two-layered crust. This model can serve as a basis in the process of locating earthquakes and explosions in and near the Scandinavian area. The values of the wave velocities with their standard deviations are (km/s):Pn 7.87±0.02,P * 6.69,Pgl 6.27±0.03,Sn 4.55±0.03,S * 3.69±0.03,Sgl 3.54±0.02,Sg2 3.40±0.01 andRg 2.81±0.02. Except forRg, these values, like those of the thicknesses of the two horizontal layers-the granitic layer 10 km and the basaltic layer 26 km-are similar to the values found byBåth [1] in 1971 for the same area. A more extensive material from explosions at various places in and around Sweden would give still more reliable values and might also be helpful in the construction of more local travel-time tables.
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    Pure and applied geophysics 113 (1975), S. 683-693 
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    Notes: Summary The earthquake activity in Europe is investigated in the paper using return periods of earthquakes in fifteen European seismic regions. The variations of return periods are compared with the fundamental structure of Europe and with the observed migrations of epicentres. The probabilities of occurrence of earthquakes and their return periods are obtained by applying the theory of largest values to the data in Kárník'sCatalogue of European Earthquakes 1901–1967.
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    Pure and applied geophysics 113 (1975), S. 713-734 
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    Notes: Abstract The structure and dynamics of severe convective storms and their mesoscale environments is described on the basis of current literature. Numerical modeling of regional and cloud-scale meteorology is reviewed with respect to its contribution to the understanding of convective storm evolution. Observation techniques are surveyed briefly. Critical questions, principally on the triggering of convective storms, are listed and a U.S. national program (Project SESAME) aimed at answering them is briefly described.
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    Pure and applied geophysics 113 (1975), S. 747-764 
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    Notes: Abstract Migration velocities of convective storms are summarized for six situations, with different environmental wind fields. Small-and medium-sized storms generally moved to left of the direction of, and at speeds somewhat less than, the vector mean wind in the troposphere. Large-diameter (ca. 20–30 km) storms generally deviated to the right, in proportion to their sizes and to the veering of wind with height. This behavior, and the tendency for large storms to move appreciably slower than the mean wind, are even more pronounced when giant clusters of thunderstorms are considered. An example is analyzed in which a multicellular storm, 80 km wide, moved 55° to right of the mean wind and with half its speed. This behavior results from a characteristic pattern of propagation, in which new cells tend to form on the general upwind side of the cluster, with the larger and more intense cells developing on its right flank. The individual cells move through the cluster, dissipating on approach to its advancing and left flanks. Preferential formation of cells toward the rear side of the cluster is shown to be compatible with the probable origin and trajectories (relative to the moving storm) of air ascending from the lower part of the subcloud layer. The sometimes-observed rapid movement of large multicellular storms to left of the mean wind is partly accounted for by an opposite (left forward flank) pattern of propagation.
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    Pure and applied geophysics 113 (1975), S. 837-849 
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    Notes: Abstract The latent heat released by cumulus clouds is very important to the energies of many large-scale tropical disturbances. The number of cumulus clouds involved in these disturbances is usually very large. The collective effects of cumulus clouds must therefore be incorporated into a large-scale model in a parameterized fashion. Present parameterization schemes are briefly reviewed. Recent advances in our understanding of the control and feedback processes between cumulus clouds and the large-scale circulations are discussed. Emphasis is placed on the implications of the results of recent diagnostic studies on the future development of the theory of cumulus parameterization.
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    Pure and applied geophysics 113 (1975), S. 851-867 
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    Notes: Abstract Observations of air flow in and around convective clouds are summarized and discussed in light of the requirements for parameterization of midlatitude convection. Both theory and observation indicate that a substantial portion of the compensating subsidence occurs as dry downdrafts in the immediate vicinity of convective clouds, which suggests that an additional physical mechanism is necessary in linking convection to the large scale. A conceptual three-dimensional model of midlatitude organized convection along with its implications for parameterization, particularly in mesoscale modeling, is presented. The effects of moist downdrafts are also considered and some differences between midlatitude and tropical convection are discussed.
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    Pure and applied geophysics 113 (1975), S. 909-923 
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    Notes: Abstract Equations are developed to describe the energetics of atmospheric convection as simulated by a two-dimensional axisymmetric numerical cloud model with parameterized microphysics of the liquid phase. Expressions that are compatible with the Boussinesq cloud model are given for specific energy, energy density, and energy flux at each grid point, and variations in time and space are considered. Energy is subdivided into categories, including kinetic energy, potential energy, thermal enthalpy, and latent enthalpy, so that the relative importance of various cloud properties and processes to the transformation and redistribution of energy can be studied. One of the prime goals of the investigation is to gain better understanding of the ways in which cloud-scale convection in an ensemble of cells affects circulations of larger scale. A description of the use of the energy equations in an actual numerical experiment is given in a companion report.
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  • 88
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    Description / Table of Contents: Summary The Guil valley permian volcanic rocks have NRM whose direction is very near to the plane of alpine schistosity affecting these rocks. During the alpine orogeny, their permian magnetization was probably modified by tectonic stresses (mechanical modification, or new magnetization by piezo-magnetic effect). The NRM of the Guil valley rocks cannot be used as a reference for geotectonic study of the Alps.
    Notes: Résumé Les roches volcaniques permiennes de la vallée du Guil présentent une ARN de direction voisine du plan de la schistosité alpine qui les affecte. Leur aimantation permienne a probablement été modifiée, lors de l'orogénèse alpine, par les efforts tectoniques (modification d'origine purement mécanique, ou acquisition d'une nouvelle aimantation par effet de pression). L'ARN des roches du Guil ne peut donc pas être prise en référence pour une étude géotectonique de l'arc alpin.
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  • 89
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    Pure and applied geophysics 114 (1976), S. 701-710 
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    Notes: Abstract A spectral theory of seismic sources is developed which treats earthquake foci as band-pass filters. This concept is applied to focal mechanisms of the type double-couple with moment, and the obtained spectral function of the source is compared with those obtained by other authors. Finally some formulae for the determination of geometric and dynamic source parameters from the ‘bandpass’ parameters are presented.
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  • 90
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    Pure and applied geophysics 114 (1976), S. 743-743 
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  • 91
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    Pure and applied geophysics 114 (1976), S. 747-751 
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    Notes: Abstract Observations of surface waves depend both on the structure traversed and the nature of the source, and therefore inversion of surface wave data can yield information about both structure and sources. The available methods for structural inversion are compared and discussed and a suggestion made for improved source inversion.
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  • 92
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    Pure and applied geophysics 114 (1976), S. 727-739 
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    Topics: Geosciences , Physics
    Notes: Abstract The scale invariant inclusion theory of failure is applied to the problem of aftershock sequences. In the inclusion theory, a macrocrack, or void of low aspect ratio, the length of which depends upon the magnitude of the impending mainshock, forms within the inclusion zone of the impending earthquake. The fault zone that precedes the inclusion zone represents that part of the macrocrack that has closed. It is shown that bifurcation (branching) of the macrocrack and its associated fault must occur within the focal region of the inclusion during the growth phase of the earthquake. The bifurcation process produces extensive faulting of the material that comprises the focal region. A prediction of the inclusion theory is that each fault within the focal region will terminate within a zone of concentrated dilatancy that may or may not be in an unstable state. When the zone is unstable, an aftershock will occur. It is shown that these inclusion zones will, on the average, occur near the boundaries of the focal region. Failure of these unstable zones leads to additional failures within the interior portions of the focal region. These failures represent ‘lock point’ failures along the fault(s) and will, in general, exhibit few or no additional aftershocks. The bifurcation model of aftershock sequences leads to five results: (1) The aftershock sequence will exhibit an inverse hyperbolic time decay law when the stresses that are applied at distances far removed from the hypocenter remain constant during the sequence and when there isno interaction between the brittle lithosphere (where aftershocks occur) and the underlying asthenosphere. (2) The mean magnitude of any group of aftershocks within the sequence will be approximately constant in time. (3) The aftershocks will, in general, have focal mechanisms identical to that of the mainshock. (4) Large seismic events that occur throughout the aftershock zone will be independent of one another when the aftershocks are sufficiently far apart (∼two-three ‘fault’ lengths) and when the applied tectonic stresses remain constant during the sequence. (5) The bifurcation model predicts that theb-value of the aftershock sequence will be 1.0 when both the Utsu relationship between aftershock area and mainshock magnitude and the Gutenburg Richter frequency-magnitude relationship are satisfied.
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  • 93
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    Pure and applied geophysics 114 (1976), S. 753-763 
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    Topics: Geosciences , Physics
    Notes: Summary A detailed description is given of a data analysis procedure for phase velocity determination from long period seismograms.
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  • 94
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    Pure and applied geophysics 114 (1976), S. 765-774 
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    Notes: Summary Three methods of computing the partial derivatives of dispersion curves are briefly described and compared: numerical differentiation, variational methods and an implicit function method.
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  • 95
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    Pure and applied geophysics 114 (1976), S. 775-790 
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    Notes: Summary The dispersion of higher modes of surface waves over a region covered by an array of stations can be measured by applying a frequency-wavenumber transform to segments of the signals in these stations, centered at a number of group-velocities. Thus, at a fixed period, modes appear as separate maxima in a display of the power spectrum on a phase-velocity vs. group velocity plane. For regions of mild lateral heterogeneity, the main source of error is shown to be due to the inadequacy of the array-response. Numerical experiments with synthetic signals indicate that a precision of the order of 1% can be obtained with a realistic number of stations. Improvements should be obtained by averaging data obtained from different events. The danger of misidentification of modes can be reduced by iteratively removing the sidelobes from the mode-separation diagram.
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  • 96
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    Pure and applied geophysics 114 (1976), S. 821-832 
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    Topics: Geosciences , Physics
    Notes: Summary Two different viewpoints of the phase velocities of the elastic surface waves in isotropic, laterally inhomogeneous media have led to inconsistent results. Arguments in terms of surface wave modes give the conclusion that the phase velocity is independent of the propagation direction, while the outcome of calculations based on a constructive interference of body waves in a surface layer is that the phase velocity is dependent on the propagation direction. Both arguments are summarized and an error in the calculations giving dependence is pointed out. The calculations and observations of surface wave amplitude changes in laterally inhomogeneous media are also summarized.
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  • 97
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    Pure and applied geophysics 114 (1976), S. 877-878 
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  • 98
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    Pure and applied geophysics 115 (1977), S. 301-316 
    ISSN: 1420-9136
    Keywords: Stress drop ; Earthquake source theory ; Earthquake source dimension
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract We discuss the inversion of stress drops from seismic observations on the basis of crack or stress-drop models of earthquake mechanism. Since a formal inverse problem cannot be posed at present we discuss implications of solutions to direct problems. We first discuss the static approximations used to obtain stress drop from seismic moment and source dimensions. We show that the geometrical effects are quite significant if only one source dimension has been retrieved from seismic observations. The effect of variable stress drop is discussed and we show that the inverted stress drop is not a simple average of the actual stress drops on the fault. We discuss the energy release during faulting and show that the apparent stress has a complicated relation to the stress drop on the fault. We also show that the static stress drops obtained by seismologists are a lower bound to the actual dynamic stress drops on the fault. This may in part explain disagreements with laboratory results. Finally, we discuss the inversion of source dimensions from the far-field radiation. We analyse two extreme, simple dynamical source models, a circular fault and a rectangular fault and show that geometry has a much more pronounced effect on radiation than is usually acknowledged.
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  • 99
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    Pure and applied geophysics 115 (1977), S. 317-331 
    ISSN: 1420-9136
    Keywords: Stress drop ; Intraplate stress ; Apparent stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The magnitude of shear stress in the lithosphere is bounded from below by the apparent stress and stress drop during intraplate earthquakes. Apparent stresses and stress drops for a number of mid-plate earthquakes are calculated from the earthquake magnitude, SH wave amplitude spectra, and estimates of the length of the fault zone. Apparent stresses vary between 0.1 and 2 bars, ifm b is used as a measure of seismic energy, and stress drops lie between 2 and 70 bars. There is no systematic difference in either apparent stress or stress drop between these intraplate events and typical plate boundary earthquakes. These bounds on intraplate shear stresses are consistent with the inference from current models of plate tectonic driving forces that regional stress differences in the plates are typically on the order of 100 bars. The highest stress drops measured for midplate earthquakes under this model represent nearly total release of local tectonic stress.
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  • 100
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    Pure and applied geophysics 114 (1976), S. 919-923 
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