Temperature effects on Trichogramma pretiosum Riley and Trichogrammatoidea annulata de Santis

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 30degreesC), 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 30degreesC. T. annulata, however, developed slightly faster than T. pretiosum at 15degreesC. Emergence rates of both species were above 89%. The temperature threshold. for T. pretiosum and T. annulata was 11degreesC and the number of degree-days required. for their development was 126.9 and 122.3, respectively. Parasitization was maximal at 25degreesC. T. annulata, however, parasitized significantly more hosts than T. pretiosum ill the entire temperature range. Temperature had no effect in brood size. T. annulata progeny consisted predominantly of males, except at 15degreesC, whereas in T. pretiosum it consisted predominantly of females, except at 30degreesC. Parental females lived longer than males.