Caught in an evolutionary trap : worker honey bees that have drifted into foreign colonies do not invest in ovary activation

Abstract

Drifting, the phenomenon whereby workers from one colony find their way into a foreign colony, is widespread in social insects. In apiaries of the honey bee Apis mellifera, orientation errors lead to high rates of worker drift. Given that A. mellifera workers in apiaries enter foreign colonies accidentally, do they continue to refrain from laying eggs in the foreign colony, or do they behave in their evolutionary interests and attempt to lay eggs? We propose two hypotheses: the “lost losers” hypothesis, where lost workers do not invest in personal reproduction, and the “lost social parasites” hypothesis, where lost workers detect that they are in a foreign colony and do invest in personal reproduction. Previous work has used complete ovary activation as an assay for testing whether workers invest in personal reproduction, but this may not detect subtle reproductive investments in queenright colonies. We instead look at the full range of ovary activation in natal and non-natal workers, because partial activation may signal preparation for future reproduction. We show that in queenright colonies, non-natal workers have the same low degree of ovary activation as their natal counterparts, which supports the hypothesis that drifted bees are “lost losers” caught in an evolutionary trap.