Feeding Activity and Life History Characteristics of the Generalist Predator, Chrysoperla Carnea (Neuroptera: Chrysopidae) at Different Prey Densities

Abstract

Larvae of the common green lacewing, Chrysoperla carnea (Stephens) (Neuroptera :Chrysopidae),were fed with different densities of Hyalopterus pruni (Geoffer) (Homoptera: Aphididae) in Petri dishes under laboratory conditions. Functional response, developmental time, mortality rate and fecundity of the predator were measured. Treatments were carried out at 25 +/- 1degreesC, 65 +/- 5% RH and a 16L:8D photoperiod in a controlled temperature cabinet. Prey was given at densities of 5, 10, 20, 40, 80 160 and 250 aphids per larva per day and the number of consumed prey, developmental time and mortality rate of the predator were recorded daily. Larvae of C. carnea responded to increasing prey densities with increasing food consumption and older larval stages displayed a higher rate of predation than younger ones. The behaviour of each of the three larval stages matched Holling's type 11 functional response. Larvae were able to complete their development in each of the seven prey densities, although increased prey densities reduced developmental time and mortality rate. Increased prey consumption in immature stages resulted in a higher net reproduction rate (R-0) and the intrinsic rate of increase (r(m)) of adult females.