Functional response of the predators Podisus maculiventris (Say) and Podisus nigrispinus (Dallas) (Het., Pentatomidae) to the beet armyworm, Spodoptera exigua (Hubner) (Lep., Noctuidae): effect of temperature

Predation abilities of Podisus maculiventris and Podisus nigrispinus on cat erpillars of the beet armyworm, Spodoptera exigua (Hubner), were compared a t three different temperatures (18, 23 and 27 degreesC) by performing funct ional response tests. In both species, predation capacity was a function of temperature and prey density: more prey were captured as temperature and n umber of prey offered increased. Results indicated that type II and III fun ctional responses provided the best fit to the data obtained for P. nigrisp inus at 18 and 23 degreesC, and at 27 degreesC, respectively. However, the data for P. maculiventris showed a better fit to type II at 18 degreesC and to type III at higher temperatures. Tn both pentatomids the handling time decreased with increasing temperature. At higher temperatures, P. nigrispin us demonstrated greater predation rates than P. maculiventris. The implicat ions of these findings for the control of caterpillar pests in glasshouses are discussed.