Opportunistic discrimination of alien eggs by social wasps (Polistes biglumis, Hymenoptera Vespidae): a defense against social parasitism?

Foundresses of the social wasp Polistes biglumis were tested to see whether they were able to recognize alien eggs experimentally introduced into thei r own nests. Foundresses removed alien conspecific reproductive-destined eg gs while they accepted worker-destined eggs. The results indicate that soci al wasps discriminate among eggs and that they discriminate against alien e ggs destined to produce unrelated reproductives. P. biglumis is a strictly solitary founding species, with no reproductive competition within colonies ; thus, brood discrimination abilities could have evolved as a counteradapt ation against intra- and inter-specific brood parasitism.