Temperature Response of Two Strains of Ceranisus menes (Hymenoptera: Eulophidae) Reared on Thrips palmi (Thysanoptera: Thripidae)

Abstract

The development response to temperature of a Japanese uniparental strain and a Thai biparental strain of Ceranisus menes (Walker) (Hymenoptera: Eulophidae) was studied. The parasitoids were reared on first instar Thrips palmi larvae in incubators at constant temperatures of 21, 23, 25, 27 and 29C. Total developmental time decreased with the increase of temperature from 35.1 to 21.9 days in females and from 33.4 to 18.8 days in males. Lowest mortality (12%) was recorded in both strains at 23C and highest (95%) in the Japanese strain at 29C. Seventy-three percent of the Thai parasitoids survived at 29C, but 39% mortality was observed at 21C. Percent parasitism ranged from 23.8 to 28.9% at 25-29C, but decreased to 11.5% at 21C. The sex ratio (male:female) was not affected by temperature and averaged 1:1.9. A thermal constant of 500 degree-days and a developmental threshold of 8C (from egg to adult emergence) were obtained for both Japanese and Thai females. For the Thai males, the thermal constant was 333.3 degree-days and the minimum threshold was 13.7C.