Effect Of Temperature On Life History And Parasitization Behavior Oftrichogramma Achaeaenagaraja And Nagarkatti (Hym.: Trichogrammatidae)

Trichogramma achaeaeNagaraja and Nagarkatti (Hymenoptera: Trichogrammatidae) is currently used as biological control agent for several lepidopteran pests. Knowledge of thermal requirements is essential to optimize its rearing procedures and inundative releases. The biological characteristics and two-sex life table parameters ofT. achaeaewere determined at five constant temperatures (15, 20, 25, 30, and 35 degrees C) usingEphestia kuehniellaZeller (Lepidoptera: Pyralidae) eggs.T. achaeaewas able to develop and survive from 15 degrees C to 30 degrees C, but not at 35 degrees C. Temperature significantly affected the preadult development time and adult longevity, decreasing when temperature increased from 15 degrees C to 30 degrees C. Temperature significantly altered the sex ratio, being female biased between 15 degrees C and 25 degrees C. Age-stage, two-sex life table analysis indicated that net reproductive rate (R-0) was highest at 20 degrees C. Both the intrinsic rate of increase (r) and finite rate of increase (lambda) increased with increasing temperature, while the mean generation time (T) decreased significantly. In addition, functional response ofT. achaeaewas studied, being significantly affected by temperature and host egg density, displaying a Holling type-I at 15 degrees C and a Holling type-II at 25 degrees C. The relevance of these results is discussed for the use ofT. achaeaeas biological control agent.