Bees produce males but only the required amount - sensibe bees

Honey bees have an excellent system whereby they produce exactly the number of males they need, with the majority of individuals developing as productive (female) workers; many aphid species only produce males when conditions become harsh – the rest of the time females give birth only to females by parthenogenesis (reproduction without fertilisation) . Both bees and aphids thus combine rapid adaptation and exploitation of resources with longer-term evolutionary flexibility through genetic recombination in sexual reproduction