Functional Response of Lyctocoris campestris (F.) Adults: Effects of Predator Sex, Prey Species, and Experimental Habitat

The functional response of Lyctocoris campestris (F.) (Heteroptera: Anthocoridae) to Plodia interpunctella Hubner (Lepidoptera: Pyralidae), Tribolium castaneum Herbst (Coleoptera: Tenebrionidae), and Oryzaephilus surinamensis (L.) (Coleoptera: Cucujidae) was determined. Each sex of the predator was evaluated in experimental arenas with and without shelled corn to determine the role of prey species and habitat in predation. Its rate of predation on a given prey species was measured by exposing a single predator to one of eight prey densities (2, 4, 8, 12, 16, 24, 32, and 40) in a 118-ml glass arena over a 24-h period. Both sexes of the predator showed a typical Type II functional response, with the Holling disk equation as an acceptable model, for all three prey species in both corn and noncorn situations. Analysis of variance for the entire experiment indicated that prey density contributed significantly to predator response (P = 0.0001), and that females killed more prey than males, but this was marginally significant (P = 0.07). Both sexes showed a higher response when corn was absent and both showed differential responses to prey species. The relative response of females to prey was P. interpunctella > T. castaneum > O. surinamensis, whereas the response of males was P. interpunctella > O. surinamensis > T. castaneum. Instantaneous rate of prey discovery did not differ among treatments, indicating that search strategy was less important than handling time in predatory response.