Reproductive physiology, dominance interactions, and division of labour among bumble bee workers
Bumble bee workers (Bombus bifarius, Hymenoptera: Apidae) exhibit aggression toward one another after the colony begins producing female reproductive offspring (the competition phase). Workers in competition phase colonies must continue to perform in-nest tasks, such as nest thermoregulation, and to...
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Published in | Physiological entomology Vol. 29; no. 4; pp. 327 - 334 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Oxford, UK; Malden, USA
Blackwell Science Ltd
01.09.2004
Wiley Subscription Services, Inc |
Subjects | |
Online Access | Get full text |
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Summary: | Bumble bee workers (Bombus bifarius, Hymenoptera: Apidae) exhibit aggression toward one another after the colony begins producing female reproductive offspring (the competition phase). Workers in competition phase colonies must continue to perform in-nest tasks, such as nest thermoregulation, and to forage for food, to rear the reproductives to maturity. Therefore, competition phase workers are faced with potentially conflicting pressures to work for their colonies, or to compete for direct reproduction. The effects of reproductive competition on worker task performance were quantified by measuring relationships of worker body size, reproductive physiology, and aggression with their rates of task performance. If worker division of labour was strongly affected by competition, it was predicted that fecund workers would avoid performing nest maintenance and foraging tasks, focusing instead on reproductive behaviour. Furthermore, it was predicted that fecund workers would dominate their nest mates, and that subordinate workers would perform nonreproductive tasks at higher rates. Worker aggression was associated closely with direct reproductive competition. Both aggression and brood interaction rates were related positively with ooctye development. Furthermore, foraging was associated negatively with ovarian development. However, in-nest and foraging task performance rates were not associated with social aggression. The results support a partial role for reproductive competition in worker polyethism. Although worker aggression did not directly affect polyethism, reproductively competent workers avoided foraging tasks that would remove them from egg-laying opportunities. Reproductively competent workers did perform in-nest tasks, suggesting that these tasks entail little cost in terms of reproductive competition. |
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Bibliography: | istex:55050B3D7F3EBB8844AB0AEF82A90BAAE67C7728 ArticleID:PHEN388 ark:/67375/WNG-S9RJT05Q-M ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 0307-6962 1365-3032 |
DOI: | 10.1111/j.0307-6962.2004.00388.x |