Temperature effects on Trichogramma pretiosum Riley and Trichogrammatoidea annulata De Santis

RESUMO

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 30º C), RH 70 ± 10 percent, 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 30º C. T. annulata, however, developed slightly faster than T. pretiosum at 15º C. Emergence rates of both species were above 89 percent. The temperature threshold for T. pretiosum and T. annulata was 11º C and the number of degree-days required for their development was 126.9 and 122.3, respectively. Parasitization was maximal at 25º 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 15º C, whereas in T.pretiosumitconsisted predominantly of females, except at 30º C. Parental females lived longer than males