Impact of egg-quality and its laying pattern on the fate of egg-cannibalism and intraguild predation in ladybirds

Abstract

We investigated the impact of egg-quality and its laying pattern on the incidence of cannibalism and intraguild predation in ladybirds. We manipulated quality by using two species of ladybirds’ eggs and the pattern of egg-laying by arranging the eggs singly or in cluster and using second, third and fourth instar larva of two ladybird species, Coccinella septempunctata L. and Menochilus sexmaculatus (Fabricius), as predators. We found that second instars of both ladybird species indulged in egg-cannibalism, whereas third and fourth instars were potential intraguild predators and consumed heterospecific eggs. On the other hand, linearly arranged and clustered eggs of M. sexmaculatus were least protected by higher instars of C. septempunctata, while clustered eggs of C. septempunctata got a refuge from M. sexmaculatus higher stage larvae due to aposematism in eggs. It is concluded that C. septempunctata was an intraguild predator of eggs of M. sexmaculatus in starved conditions, and the egg-quality and pattern of egg-laying can affect the fate of egg-cannibalism and intraguild predation.