Apis florea and Apis cerana workers do not discriminate between queen-laid and worker-laid Apis mellifera eggs

Abstract

While honey bee workers have functional ovaries, worker reproduction is rare in colonies with a laying queen. An important mechanism by which functional worker sterility is enforced is worker policing—any behaviour of workers that prevents other workers from reproducing. In honey bees, policing workers identify worker-laid eggs and eat them. Policing workers apparently distinguish queen-laid eggs from eggs laid by workers using as yet unidentified chemical signals placed on eggs. These signals are conserved across evolutionary time because the Western hive bee Apis mellifera can distinguish queen- and worker-laid eggs of the phylogenetically distant dwarf honey bee Apis florea. However A. mellifera cannot distinguish queen- and worker-laid eggs of the more closely related species Apis cerana. Here we show that A. cerana and A. florea workers do not distinguish queen-laid from worker-laid eggs of A. mellifera, even though A. cerana (but not A. florea) tolerate A. mellifera eggs for extended periods.