TY - JOUR
T1 - Division of labor and the evolution of task sharing in queen associations of the harvester ant Pogonomyrmex californicus
AU - Cahan, Sara Helms
AU - Fewell, Jennifer
N1 - Funding Information:
Acknowledgments Our heartfelt thanks to the many people from the Social Insect Research Group at ASU who contributed to watching queens at all hours, especially Glennis Julian and Ekwutosi Okoroh. Thanks also to Bob Johnson and Liz Smith for queen collection in 1994, and to Emma Harrison for collection and weighing assistance. This work was supported in part by an NIMH grant R29 MH51329 to J.H.F. Additional financial support during manuscript preparation was provided by grants from the Swiss National Foundation to L. Keller.
PY - 2004/5
Y1 - 2004/5
N2 - Division of labor is a key factor in the ecological success of social groups. Recent work suggests that division of labor can emerge even without specific adaptations for task specialization and that it can appear in incipient social groups as a self-organizational property. We investigated experimentally how selection and self-organization may interact during the evolution of division of labor by examining task performance in groups of normally solitary versus normally social ant queens. We created social pairs of colony-founding queens from two populations of the ant Pogonomyrmex californicus, one in which queens are normally solitary and one in which queens form foundress groups, and observed their behavior during nest excavation. In both populations, one of the two queens usually performed most of the excavation, becoming the excavation specialist. We could predict which queen would become the specialist based on their relative propensities to perform the task in other contexts, consistent with a variance-based model of task specialization. The occurrence of specialization even when group members were not adapted to social life suggests that division of labor may well have been present in incipient queen groups. However, division of labor can result in cost skew among group members, and thus, paradoxically, within-group selection may constrain or even reduce specialization. Consistent with this effect, pairs of normally solitary queens were significantly more asymmetrical in their task performance than normally social pairs, in which both queens nearly always performed the behavior to some degree.
AB - Division of labor is a key factor in the ecological success of social groups. Recent work suggests that division of labor can emerge even without specific adaptations for task specialization and that it can appear in incipient social groups as a self-organizational property. We investigated experimentally how selection and self-organization may interact during the evolution of division of labor by examining task performance in groups of normally solitary versus normally social ant queens. We created social pairs of colony-founding queens from two populations of the ant Pogonomyrmex californicus, one in which queens are normally solitary and one in which queens form foundress groups, and observed their behavior during nest excavation. In both populations, one of the two queens usually performed most of the excavation, becoming the excavation specialist. We could predict which queen would become the specialist based on their relative propensities to perform the task in other contexts, consistent with a variance-based model of task specialization. The occurrence of specialization even when group members were not adapted to social life suggests that division of labor may well have been present in incipient queen groups. However, division of labor can result in cost skew among group members, and thus, paradoxically, within-group selection may constrain or even reduce specialization. Consistent with this effect, pairs of normally solitary queens were significantly more asymmetrical in their task performance than normally social pairs, in which both queens nearly always performed the behavior to some degree.
KW - Division of labor
KW - Pogonomyrmex californicus
KW - Queen associations
KW - Specialization
KW - Task sharing
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U2 - 10.1007/s00265-003-0746-5
DO - 10.1007/s00265-003-0746-5
M3 - Article
AN - SCOPUS:2442553819
SN - 0340-5443
VL - 56
SP - 9
EP - 17
JO - Behavioral Ecology and Sociobiology
JF - Behavioral Ecology and Sociobiology
IS - 1
ER -