Asymmetric intraguild predation of Harmonia axyridis (Pallas, 1773) (Coleoptera: Coccinellidae) on a native Coccinellidae guild

Abstract

Harmonia axyridis is an exotic species that can cause serious impacts on native biodiversity in areas where it is introduced to act as a biological control agent. This predator is often involved with intraguild predation, in most cases with aphids predators. Here, we report the results of experiments designed to understand the outcome of the invasion of H. axyridis on native coccinellid aphidophagous guilds using intraguild predation as a theoretical framework. Tests were conducted to determine the interactions between 1st and 4th instars larvae and H. axyridis adults, with Cycloneda sanguinea, Cycloneda pulchella, Eriopis connexa and Hippodamia convergens larvae, as well as eggs predation rate. Two treatments were used: absence and presence of food, Cinara atlantica. The results showed that 1st and 4th instars larvae and H. axyridis adults are able to prey on larvae and eggs of four Coccinellidae species analyzed, and also their own eggs, showing that this exotic species is a dominant predator in this guild of aphidophagous coccinellids. Adding to these results, studies are recommended, especially the monitoring of these species in the field in the long run, reporting their abundance and diversity as well as their behavior and impact within aphidophagous guilds, especially in Coccinellidae species.