Intercropping collard plants with coriander modulates behavioral interactions among aphidophagous predators by altering microhabitat structure

Abstract

Intercrops increase microhabitat structural complexity and may affect the strength of intraguild predation, facilitating the coexistence of species in aphidophagous guilds that share similar resources. Microhabitat structure may also influence the outcome of intraguild predation among larval stages by influencing the selection of oviposition sites. We investigated how intercrops affect intraguild predation, consumption, and behavioral interactions among various life stages of aphidophagous predators. We examined interactions among conspecific and heterospecific pairs of Cycloneda sanguinea (Coleoptera: Coccinellidae) and Chrysoperla externa (Neuroptera: Chrysopidae) in collards planted in monoculture (simple microhabitat) or intercropped with coriander (complex microhabitat). Heterospecific pairs had reduced impact on their shared prey, especially in monocultures. Chrysoperla externa larvae acted as intraguild predators more often than C. sanguinea larvae and changed the foraging behavior of the intraguild prey. Microhabitat complexity in the intercrop did not extend the period of larval coexistence when intraguild predation was strong. Cycloneda sanguinea avoided laying eggs in the presence of C. externa in the monoculture, and tended to lay more eggs in sheltered locations in the intercrop. Conversely, C. externa laid more eggs in the presence of C. sanguinea, especially in the monoculture. Our findings suggest that the increased microhabitat complexity of the intercrop reduced both the encounter rate between intraguild prey and intraguild predator during larval stages, and the overlap in oviposition site selection by adult females. Our findings highlight the relevance of plant diversity and microhabitat architecture in promoting the coexistence of aphidophagous predators throughout their life cycle, and their potential to increase the efficiency of conservation biological control.