3). This is surprising, as initial egg

number is presumably homeostatically regulated in order to preserve energy for brood rearing, and thus queen egg-laying should be responsive to the total quantity of eggs regardless of queen number. One possible explanation is that the increase in HF productivity stems not from increased investment into egg-laying, but increased brood survival. Because queens do not forage during the founding period, they are inherently constrained in their initial productivity by their own Quizartinib research buy energetic reserves, which are used to provide resources to the developing worker cohort. Founding queens typically rear only a small proportion of the initial batch of eggs laid, with the remainder

consumed by developing larvae (Baroni Urbani, 1991; Wheeler, 1994; Liu et al., 2001). The fact that single and paired nests did not differ in per capita productivity suggests that the LF queen fully invests in brood rearing despite significantly lower maternity. If LF queens provide generalized brood care, a larger proportion of eggs may hatch and develop successfully for both queens and result in an effective increase in productivity for the HF queen. The results of this study suggest that

the component PI3K inhibitor elements of eusociality are surprisingly easy to produce through self-organizing mechanisms, and raise the possibility that initial social groups might have already possessed the rudiments of a ‘derived’ social structure without requiring intervening secondary adaptations. This is consistent with earlier suggestions that nonreproductive helping originated as an automatic consequence of failing to disperse, arising spontaneously when nondispersing adult offspring are exposed to the provisioning stimulus of begging siblings find more (West-Eberhard, 1987; Jamieson, 1989). A recent paper suggested that evidence for an emergent origin of eusocial traits would argue against the importance of kin selection in the evolution of eusociality (Nowak et al., 2010); however, these two types of explanation operate at different levels of analysis and are not actually alternatives. It is important to distinguish between the evolutionary origin of a trait, which may well be emergent, and its evolutionary fate, which depending on its fitness returns, may be eliminated, reinforced or enhanced through underlying genetic changes (Ligon & Stacey, 1991).