Functional response of thelytokous and arrhenotokons strains of Trichogramma dendrolimi (Hymenoptera: Trichogrammatidae) to eggs of Corcyra cephalonica (Lepidoptera: Pyralidae) at different temperatures
Thelytokous forms of Trichogramma are often associated with the presence of endosymbiotic Wolbachia bacteria. Laboratory tests were conducted to evaluate the functional response of thelytokous and arrhenotokous strains of T. dendrolimi by using the factitious host, Corcyra cephalonica, at four constant temperatures (20, 25, 30 and 35 ℃ ). The results showed that the parasitism efficiency increased with increasing host egg density. Type Ⅲ functional response turned to type Ⅱ for both strains of T. dendrolimi with increasing temperature. For the thelytokous strain, the handling time was the shortest (0.0207 d) at 30℃ , and the parasitization rate was the highest (48. 31 eggs parasitized per day) at 30℃ but the lowest at 35℃. However, for the arrhenotokous strain, the handing time was the shortest (0.0188 d) at 25 ℃ , and the parasitization rate was the highest (53. 08 eggs parasitized per day) at 25℃ but the lowest at 20℃. There was a significant difference in functional response between the two strains (at 30 ℃ , the thelytokous strain, type Ⅱ; the arrhenotokous strain, type Ⅲ ). The handling time of the thelytokous strain was significantly longer than that of the arrhenotokous strain at 25℃; and 35℃ (P <0. 05) , while the situation was reversed at 30℃. These results demonstrate that the functional response of T. dendrolimi is significantly affected by host density, temperature and Wolbachia infection.
国家科技期刊平台
NSTL
万方数据
维普
