Effects of Lysiphlebus testaceipes parasitism levels on cannibalism and intraguild predation among the native ladybeetle Hippodamia convergens and the exotic Coccinella septempunctata

The endoparasitic wasp, Lysiphlebus testaceipes Cresson, along with the native ladybeetle Hippodamia convergens Guerin-Meneville and the exotic Coccinella septempunctata L. constitute part of an aphidophagous guild responsible for suppressing greenbug (Schizaphis graminum Rondani) populations in the Southern Plains of the U.S. Ladybeetles readily consume L. testaceipes within their aphid hosts, a competition dynamic known as intraguild predation, however this kind of parasitized prey is inferior in quality and unsuitable depending on the stage of parasitism. Our main objective was to examine the effects of these types of prey at varying levels of percent parasitism on the strength of intraguild predation and cannibalism between and among C. septempunctata and H. convergens. Results revealed cannibalism and intraguild predation increased with increased percent parasitism. Later stages of parasitism had the greatest negative impacts. Coccinella septempunctata was more likely to cannibalize than H. convergens and when pitted together, C. septempunctata was the dominant intraguild predator.