Kin-selected conflict in the bumble-bee Bombus terrestris (Hymenoptera : Apidae)

Kin selection theory predicts conflict in social Hymenoptera between the qu een and workers over male parentage because each party is more closely rela ted to its own male offspring. Some aspects of the reproductive biology of the bumble-bee Bombus terrestris support kin selection theory but others ar guably do nut. We present a novel hypothesis for how conflict over male par entage should unfold in B. terrestris colonies. We propose that workers del ay laying eggs until they possess information showing that egg laying suits their kin-selected interests. In colonies where queens start to lay haploi d eggs early we hypothesize that this occurs when workers detect the presen ce of queen-produced male brood in the brood's larval stage. In colonies wh ere queens start to lay haploid eggs late, we hypothesize that it occurs wh en workers detect a signal from the queen to female larvae to commence deve lopment as queens. Our hypothesis accounts for previously unexplained aspec ts of the timing of reproductive events in B. terrestris, provides ultimate explanations for the results of a recent study of mechanisms underlying qu een-worker conflict and helps explain this species' characteristic bimodal (split) sex ratios. Therefore, kin selection theory potentially provides a good explanation for reproductive patterns in B. terrestris.