The functional response, search time and handling time of the predator Scymnus (Pullus) argentinicus (Weise) were evaluated. Nymphs of 3rdand 4th instars of the greenbug, Schizaphis graminum (Rond.), were provided as food. The statistical design was randomly in a factorial 3 x 5, with three densities of the greenbug (10, 25, 35 nymphs) and four instars and adult of the predator, in 10 replications. Tests were conducted in an environmental chamber at 25± 1ºC, 70± 10% RH and 14 hours photophase. For both larvae and adults of S. (Pullus) argentinicus the amount of predated nymphs increased with the increment of aphid densities, until reaching a plateau (functional response Type II). Predation in the 4th instar was higher and greater for the density of 35 nymphs compared to the densities of 10 and 25 nymphs. The increment in predation increased, from density 10 to 25, but decreased at density 25 to 35 nymphs. The search time incresead gradually with the age of the predator, while the handling time decreased with the age. Adult females presented higher predation and searched faster for prey than males. Searching time decreased with the increase in aphid density.
Insecta; predation; functional response
