Proceedings of the Royal Society B: Biological Sciences
Cooperative breeding is generally considered an adaptation to ecological constraints on dispersal and independent breeding, usually due to limited breeding opportunities. Although benefits of cooperative breeding are typically thought of in terms of increased mean reproductive success, it has recently been proposed that this phenomenonmay be a bet-hedging strategy that reduces variance in reproductive success (fecundity variance) inpopulations living inhighly variable environments. We tested this hypothesis using long-term data on the polygynandrous acorn woodpecker (Melanerpes formicivorus). In general, fecundity variance decreased with increasing sociality, at least when controlling for annual variation in ecological conditions. Nonetheless, decreased fecundity variance was insufficient to compensate for reduced per capita reproductive success of larger,more social groups, which typically suffered lower estimatedmean fitness.We did, however, find evidence that sociality in the form of larger group size resulted in increased fitness in years following a small acorn crop due to reduced fecundity variance. Bet-hedging, although not the factor driving sociality in general, may play a role in driving acorn woodpecker group living when acorns are scarce and ecological conditions are poor.
Original Publication Citation
Koenig, W. D., & Walters, E. L. (2015). Temporal variability and cooperative breeding: Testing the bet-hedging hypothesis in the acorn woodpecker. Proceedings of the Royal Society B: Biological Sciences, 282(1816). doi:10.1098/rspb.2015.1742
Koenig, Walter D. and Walters, Eric L., "Temporal Variability and cooperative Breeding: Testing the Bet-Hedging Hypothesis in the Acorn Woodpecker" (2015). Biological Sciences Faculty Publications. 353.