Development ofTrichogramma exiguumandT. pretiosumat Five Temperature Regimes1

Abstract

Trichogramma pretiosum Riley and T. exiguum Pinto and Platner were compared in a temperature study at five constant temperatures of 15, 20, 25, 30, and 35°C. Developmental time of both parasite species in host ( Heliothis virescens [F.]) eggs decreased with increases in temperature. T. exiguum developed faster than T. pretiosum at 25 and 30°C, but not at 20°C. T. pretiosum completed development at 35°C, but T. exiguum did not. Additionally, T. pretiosum females lived longer than T. exiguum females at 20 and 25°C; longevity decreased for both species with increase in temperature. Females outnumbered males at all temperatures. There was no significant difference between species in number of females or in number of parasites completing development per host egg.