Temperature effects on Trichogramma pretiosum Riley and Trichogrammatoidea annulata De Santis

Abstract

The influence of temperature on lifetime attributes of Trichogramma pretiosum Riley and Trichogrammatoidea annulata De Santis (Hymenoptera: Trichogrammatidae) was evaluated at four constant temperatures (15, 20, 25, and 30°C), RH 70 ± 10%, photophase 14 h. Anagasta kuehniella (Lepidoptera: Pyralidae) eggs were used as hosts. Developmental times of both parasitoid species were similar when exposed to 20, 25, or 30°C. T. annulata, however, developed slightly faster than T. pretiosum at 15°C. Emergence rates of both species were above 89%. The temperature threshold for T. pretiosum and T. annulata was 11°C and the number of degree-days required for their development was 126.9 and 122.3. respectively. Parasitization was maximal at 25°C. T. annulata. however, parasitized significantly more hosts than T. pretiosum in the entire temperature range. Temperature had no effect in brood size. T. annulata progeny consisted predominantly of males, except at 15°C, whereas in T. pretiosum it consisted predominantly of females, except at 30°C. Parental females lived longer than males.