Egg laying and oophagy by reproductive workers in the polygynous stingless beeMelipona bicolor(Hymenoptera, Meliponini)

Abstract

We studied queen-worker conflict over male production in a Melipona bicolor colony, having three physogastric queens and individually marked workers, by means of observations of the processes of cell oviposition. The gender that developed from these cells showed that queens produced mainly female offspring. The overall percentage of the males that were workers’ sons was estimated between 27 and 82%. Forty-two times workers were seen to deposit a male egg, normally following the queen’s oviposition, in the same cell and in sixteen cases, the reproductive worker ate the egg already present in the cell before ovipositing in it. Workers not only were more likely to lay their egg next to that of another worker than next to a queen’s egg, they also were more likely to replace the egg already present when it was worker-derived. Their conduct agrees with predictions from kin-selection theory because workers are better served when rearing sons at the cost of other workers’ sons than at the cost of queens’ daughters.