Abstract

Abundance and diversity of natural enemies increases with higher landscape complexity. However, more species can also increase negative interactions such as intraguild predation (IGP), which could be detrimental to pest control. Direct observations of these trophic interactions are still lacking. In the present study, we employed DNA-based gut content analyses of coccinellid beetles to assess IGP (direct and coincidental) and aphid consumption. Species-specific and group-specific primer pairs were used to unveil the interactions of the most abundant coccinellid species, three cereal aphids and their associated parasitoids. In order to determine whether the landscape complexity promotes these interactions, we used replicated wheat fields in two contrasting landscape contexts over the season in central Chile. With higher abundance of coccinellids, we observed greater aphid consumption in complex contexts. The consumption of parasitized aphids was mostly detected early in complex contexts, suggesting a detrimental effect on the parasitoid population. Following molecular analysis, we can state that the aphids are important feeding resources for the coccinellid assemblage and are actively foraging on this important pest. Finally, this study demonstrates that direct IGP is a common interaction in this system, independently of the landscape context during the complete season. Nevertheless, the native Eriopis chilensis was found to be the most frequently consumed intraguild prey. In contrast with expected predictions, we found little evidence that the landscape context increased negative interactions, such as IGP and IGP-C and in turn that these decrease the control of Sitobion avenae.