Oviposition behavior of the biological control agent Aphidoletes aphidimyza (Diptera: Cecidomyiidae) in environments with multiple pest aphid species (Hemiptera: Aphididae)

Abstract

We investigated the oviposition behavior of the aphidophagous midge Aphidoletes aphidimyza (Diptera: Cecidomyiidae) when faced with multiple prey choices, i.e. plants infested with Myzus persicae or Aulacorthum solani (Hemiptera: Aphididae). When within-plant location of aphid patches was controlled for, aphid density was a significant factor in A. aphidimyza oviposition, but species was not. When location was uncontrolled, aphid species and location of aphid patches on plants (and 2 and 3-way interactions with location) became significant, along with density. Aggregations of M. persicae on plant meristems received the largest number of A. aphidimyza eggs, while A. solani-infested plants received significantly fewer eggs (this aphid species being generally distributed among lower leaves). Upon giving A. aphidimyza a choice between two patch locations, aphid species was again unimportant in oviposition decisions, while a greater correlation with aphid density was seen in aphid colonies located on young plant tissue vs. old. These results suggest that, for A. aphidimyza, perceived quality of an aphid patch as an oviposition site is influenced more by density and location of the aphid patch on the plant than by the species of aphid within the patch. Given that within-plant distribution of pest aphid species can differ, this oviposition behavior could have important implications for the efficacy of A. aphidimyza as a biocontrol agent for aphids in multi-species environments.