In a recent Biology Letters paper, we ask whether the embattled haplodiploidy hypothesis (the idea that hymenopteran females are more disposed to evolve sterile helpers than diploids are) is affected by sex-specific condition-dependence. In principle, a female bee's reproductive success may depend more strongly on her physical condition than does a male bee's reproductive success: she must face the energetically-demanding challenge of nest founding (and often overwintering), whilst males face only the challenge of succeeding in mating. (This is the opposite way around to the condition-dependent asymmetry familiar in vertebrates, where male reproductive success depends more strongly on condition).
If female quality determines future nest-founding success, altruism that increases sibling quality will be easier to evolve in haplodiploids than in diploids. More generally, we suggest that empirically quantifying the payoffs of altruism in insects has focused largely on sibling quantity (how many brothers and sisters can I raise?), but that effects on sibling quality remain incompletely understood.
Adventures of a
Dr Patrick Kennedy, Radford Lab, University of Bristol | Zoology