Who eats whose eggs? Intra- versus inter-specific interactions in starving ladybird beetles predaceous on aphids

Starving adult beetles of Menochilus sexmaculatus and Coccinella transversalis resorted to intra- and inter-specific predation in the absence of aphid prey. Particularly at high egg densities, predators consumed eggs of their own species much more readily than eggs of the other species. Between the two ladybird species, the eggs of the smaller species, M, sexmaculatus, were less vulnerable to predation from the larger species, C. transversalis than vice versa. Results further indicate that adult female beetles are capable of discriminating eggs of their own species versus eggs of alien species on physical contact. The adaptive significance of this is discussed.