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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Analytical chemistry 57 (1985), S. 1427-1433 
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Insectes sociaux 45 (1998), S. 97-109 
    ISSN: 1420-9098
    Keywords: Key words: Halictidae, pleometrosis, social evolution.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Female sweat bees in the species Halictus ligatus exhibit a wide range of reproductive roles, ranging from typically foundress or queen-like to typically worker-like. Nests are founded in spring and most are haplometrotic, that is, founded by a single foundress. A few (up to 12 %) are pleometrotic, founded by 2-6 foundresses. Variation in the proportion of multifoundress nests from year to year and from place to place suggests an adaptive basis for pleometrosis. We studied the demographic and social characteristics of 23 pleometrotic nests in an aggregation of 250-300 nests near Victoria, Ontario, in 1984, 1990, and 1991. In pleometrotic associations, dominant foundresses behaved in a manner typical of mid-summer, haplometrotic queens, while subordinates behaved like mid-summer workers. Dominant foundresses tended to be larger than subordinates. Pleometrotic nests were significantly more likely than haplometrotic nests to produce brood, and they also produced more workers. However, this early advantage did not result in the production of more reproductive brood per nest, nor did pleometrotic foundresses experience higher productivity per foundress than did haplometrotic foundresses. Relatively low relatedness among various categories of brood implied that subordinate foundresses were not closely related to dominants. We suggest that pleometrosis most likely results from accidental encounters between spring foundresses as they leave their hibernacula. Once formed, such associations confer a survival advantage on the nest as a whole, but do not result in greater reproductive brood productivity.
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  • 3
    ISSN: 1420-9098
    Keywords: Key words: Eusocial, photoperiod, temperature, behavioural phenotypes, social evolution, Halictidae.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: We compare the behaviour of daughters of Evylaeus albipes females from eusocial populations from the West of France with those from a non-eusocial population from the East of the country. When non-eusocial population females are placed in the laboratory under day lengths and temperature conditions similar to those experienced by eusocial foundresses under natural conditions, all five produced a brood of males and overwintering daughters with no workers. When 18 nests were initiated by non-eusocial foundresses under short summer daylengths but warmer than normal temperatures, two produced one worker amongst overwintering female and male brood. Both worker-producing non-eusocial females were from the warmest of the eastern localities. When foundresses of the social population are placed under day length conditions typical for the non-eusocial population but with temperature conditions that are intermediate between the two, all five produced at least one worker. Similarly, if the first brood produced by social foundresses is removed, they raise another brood that contains workers whereas non-eusocial population foundresses who have their first brood removed produce a second brood of overwintering females (although one foundress, again from the warmest of the non-eusocial localities, produced one worker in each of two broods, also with males and overwintering females). We conclude that i) non-eusocial foundresses do not readily produce workers under long summer conditions; ii) the lack of worker production by most non-eusocial population females is not because they cannot produce two broods, but because they have a tendency not to produce workers; iii) eusocial population daughters will become active without diapausing in the presence of any other female - even of the closely related E. calceatus, unless the first individual to eclose is the smallest and iv) social population foundresses are incapable of producing overwintering females without the help of workers. These data show an interesting combination of flexibility and constraint on social behaviour in these bees.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Insectes sociaux 30 (1983), S. 367-375 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Resume Une bourgade deLasioglossum (E.) laticeps fut découverte sur les falaises de Charmouth, Dorset, où des nids débouchaient dans des fissures de la glaise. Les rayons de couvain de printemps et d'été étaient entourés par une cavité, agrandie à mesure de l'augmentation du nombre de cellules.L. (E.) laticeps est une abeille sociale primitive, comme le démontre la proportíon élevée des mâles dans le premier couvain (24 %) et les faibles différences morphologiques dans la caste femelle: les ouvrières sont, en moyenne, 8 % plus petites que les reines. Cette espèce semble avoir une organisation plus primitive parmi les quatre espèces du groupe deL. (E.) malachurum sur lesquelles on a des informations.
    Notes: Summary An aggregation ofLasioglossum (Evylaeus) laticeps (Schenck) was discovered on the cliffs at Charmouth, Dorset, where nests were initiatied in cracks in the clay soil. The cell clusters of both spring and summer broods were surrounded by a cavity which was enlarged as the number of cells increased.L. (E.) laticeps appears to have the most primitive social organisation of the four species of theL. (E.) malachurum species group for which data are available. Thus there is a high proportion of males in the first brood (24 %) and the morphological caste differences are slight: workers are, on average, 7 % smaller than the queens.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Insectes sociaux 41 (1994), S. 309-313 
    ISSN: 1420-9098
    Keywords: Lasioglossum ; Dialictus ; sweat bee ; solitary behaviour ; social evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Nine nests ofLasioglossum (Dialictus) tenax were excavated near Calgary, Alberta, Canada over a time period encompassing the entire brood production period in 1988. Each nest contained a maximum of one active adult female, nest productivity peaked in mid July, protandry was noted and no significant size difference between foundresses and the earlier emerging females was detected. These data suggest that this species is solitary. These results are compared with data for the sympatrically nesting eusocial speciesL. (D.) laevissimum.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Insectes sociaux 33 (1986), S. 190-205 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Resume On étudie, dans le sud de l'Ontario, l'architecture des nids deHalictus ligatus; on déterre pour cela, en 1984, plus de 130 nids. Les principales découvertes sont les suivantes. La survie des nids est plus grande sur des surfaces recouvertes de végétation que sur des sols dénudés. Les nids dont les entrées sont dissimulées sous des feuilles souffrent moins de mortalité par prédateurs et parasites que ceux dont les entrées sont apparentes. Des boucles entourant les cellules sont construites pour prévenir une trop grande humidité du sol et semblent constituer une étape intermédiaire vers la formation d'une cavité. La mortalité du couvain due à l'humidité semble résulter d'un excès d'eau que l'excavation de boucles pourrait contribuer à prévenir. Les cellules situées près de la surface peuvent souffrir d'un excès d'humidité après de fortes pluies. Les nids situés sous une végétation plus dense souffrent moins de mortalité par moisissure. Les cellules produisant des reines sont plus grandes que celles qui donnent des mâles et des ouvrières. L'usure mandibulaire est une mesure précise du creusement accompli par un individu femelle.
    Notes: Summary Nest architecture ofHalictus ligatus was studied at Victoria, southern Ontario; over 130 nests were excavated in 1984. The most important findings are as follows. Nest failure was lower in vegetated areas than in bare ground. Nests with entrances hidden under leaves may suffer less mortality from parasites than those out in the open. Loops around cells are dug in response to moist soil conditions and appear to be an intermediate step towards cavity formation. Brood mortality due to mould seemed to result from cell waterlogging which the excavation of loops may help to prevent. Cells near the surface may suffer from waterlogging after heavy rains. Nests situated in denser vegetation suffered less mortality from mould. Gyne-producing cells are larger than male or worker-producing ones. Mandibular wear is an accurate measure of the amount of excavation performed by an individual female.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Resume Nous étudions la biologie d'Evylaeus villosulus dans la nature et dans des cages d'élevage. Nous comparons des fondatrices et leurs filles, femelles, d'été, récoltées dans la nature, en utilisant les fonctions discriminantes d'une analyse multivariate. Les variables utilisées sont deux caractères de taille, deux de couleur et quatre de sculpture. Toutes les variables indiquent des différences significatives entre les générations mais les caractères de couleur et de sculpture, ne montrant pas de variation allométrique entre les générations semblent être induites par l'influence de l'environnement. Les données concernant la sex ratio de la génération d'été proviennent d'adultes prélevés dans la nature et d'autres issus de couvain élevé au laboratoire. Chez ceux-ci, comme chez ceux-là, la sex ratio est à majorité femelle dans le rapport d'environ 4∶1. Les données concernant la génération hivernante proviennent uniquement d'adultes produits en élevage; la sex ratio est à faible majorité femelle dans le rapport d'1.2∶1. Les poids nymphaux diffèrent significativement, entre les deux générations pour les femelles mais non pour les màles. En utilisant les mesures appropriées, le rapport d'investissement est d'environ 5∶1 en été et de 2∶1 en automne mais ce dernier chiffre doit être confirmé à partir d'Insectes prélevés dans la nature. Les femelles hivernantes survivent à l'éclosion du couvain d'été et récoltent du pollen en même temps que leurs premières filles. La cohabitation de plusieurs femelles de même génération survient parfois sans qu'il ne s'instaure de division du travail: des nids communaux se forment alors. De plus une mère et sa fille ont partagé un même nid éosocial. Ainsi,E. villosulus serait une espèce bivoltine fondamentalement solitaire bien qu'elle présente deux caractères généralement associés à l'eusocialité: la taille réduite des femelles de la génération d'été et la sex ratio de la génération d'été, fortement décalée vers le sexe femelle.
    Notes: Summary The biology ofEvylaeus villosulus was studied both in the field and in experimental rearing cages. Field caught females and their summer daughters were compared using multivariate discriminant functions analysis. The variables used were two size, two colouration and four sculpturing characteristics. All variables show significant differences between generations but the colouration and sculpturing characters did not show allometric variation within generations and may be environmentally induced. Sex ratio data are available for the summer generation for both field and laboratory reared brood. Both gave female biased sex ratios approximating 4∶1. Data for the overwintering generation were obtained only from the laboratory, the sex ratio was slightly female biased — 1.2∶1. Pupal weights differed significantly between generations for females but not for males. Using the appropriate values, the investment ratio is female biased in both generations; approximately 5∶1 in the summer and 2∶1 in the autumn. Overwintered females frequently survive long enough to forage simultaneously with their earlier emerging offspring. Cohabitation between females of the same generation occurs with low frequency but no division of labour results, rather communal colonies are formed. Similarly, when a mother and a daughter shared a nest, an eosocial colony resulted. Thus,E. villosulus would appear to be a basically solitary species despite exhibiting reduced size in the daughters of overwintered females and a female biased sex ratio, both of which are characteristics frequently associated with eusociality.
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 56 (1953), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 570 (1989), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Archives of Biochemistry and Biophysics 204 (1980), S. 30-40 
    ISSN: 0003-9861
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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