Intra‐ and interspecific interactions between Nephus includens and Cryptolaemus montrouzieri

The introduced coccinellid Cryptolaemus montrouzieri is extensively used by biological control practitioners against mealybugs. Potential risks on native guilds of natural enemies have recently been recognized, as C. montrouzieri has managed to establish in many of the regions, it has been released. We investigated in the laboratory the direct trophic interactions between Cryptolaemus montrouzieri and Nephus includens, a predatory coccinellid native to the Mediterranean region. For both adult coccinellid species, predation rates on conspecific or heterospecific juvenile stages, with different amounts of shared prey, were recorded after 24 h. Both predators consumed eggs and larvae, but only C. montrouzieri preyed upon pupae. In general, cannibalism decreased with shared prey abundance, regardless of species. A high level of asymmetry was found on intraguild predation, in favour of C. montrouzieri. The probability of displacement threat of N. includens by C. montrouzieri in nature, in addition to possible effects of the studied trophic interactions on the outcome of biological control, is discussed.