Spatial and temporal cooccurrence among Neotropical native coccinellids and the exotic Harmonia axyridis

Abstract

Coccinellids are important biological control agents and aphid predators in horticultural crops around the world. Neotropical Cycloneda sanguinea, Eriopis connexa and Coleomegilla quadrifasciata octodecimpustulata, and the exotic Harmonia axyridis (all Coleoptera: Coccinellidae), are predators that mainly feed on aphids. In this work we described the abundance of these coccinellid species and their spatial and temporal cooccurrence in agroecological eggplant crop of Argentina. We also estimate the intensity and symmetry of the intraguild predation between C. quadrifasciata octodecimpustulata and the other species in laboratory experiments. Both temporal and spatial segregation was observed. H. axyridis was the strongest intraguild predator in the interaction with C. quadrifasciata octodecimpustulata, and this latter was the strongest intraguild predator in interaction with C. sanguinea and E. connexa. In this context, native coccinellid species would be vulnerable to the exotic and invasive H. axyridis; however, the lack of cooccurrence of this species with the native ones, under conditions of low density of extra-guild prey would indicate that spatial segregation could be the mechanism by which these species coexist in the eggplant crop.