FUNCTIONAL-RESPONSE OF LYCTOCORIS-CAMPESTRIS (F) ADULTS - EFFECTS OF PREDATOR SEX, PREY SPECIES, AND EXPERIMENTAL HABITAT

The functional response of Lyctocoris campestris (F.) (Heteroptera: An thocoridae) to Plodia interpunctella Hubner (Lepidoptera: Pyralidae), Tribolium castaneum Herbst (Coleoptera: Tenebrionidae), and Oryzaephil us 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 pred ation. Its rate of predation on a given prey species was measured by e xposing 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, wi th the Holling disk equation as an acceptable model, for all three pre y species in both corn and noncorn situations. Analysis of variance fo r the entire experiment indicated that prey density contributed signif icantly to predator response (P = 0.0001), and that females killed mor e prey than males, but this was marginally significant (P = 0.07). Bot h sexes showed a higher response when corn was absent and both showed differential responses to prey species. The relative response of femal es to prey was P. interpunctella > T. castaneum > O. surinamensis, whe reas 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 h andling time in predatory response.