The functional responses of two parasitoids, Eretmocerus hayati Zolnerowich ＆ Rose and Encarsia sophia Girault ＆ Dodd, of whitefly Bemisia tabaci Gennadius Middle East-Asia Minor 1 were studied under laboratory cond...The functional responses of two parasitoids, Eretmocerus hayati Zolnerowich ＆ Rose and Encarsia sophia Girault ＆ Dodd, of whitefly Bemisia tabaci Gennadius Middle East-Asia Minor 1 were studied under laboratory conditions. In addition, the influence of host density and host stage on the competitive interactions between the two parasitoids, and biological control effect on whitefly were evaluated. In the functional response study, adult parasitoids were tested individually, with a conspecific or heterospecific competitor. Both Er. hayati and En. sophia exhibited a type II response to increasing host density, whether a conspecific or heterospecific competitor was present or not. Difference of searching rates and handling times between treatments suggested interference interactions existed between two parasitoid species. In the host stage preference study, two parasitoid species were jointly tested. Er. hayati had a competitive advantage over En. sophia when provided young host instars （first and second instar）, whereas no advantage was found on old host instars （third and fourth instar）. The biological control effect ofEr hayati and En. sophia in different introductions varied with host density. However, the effect of host instar on host mortality was not significant. These findings provide information for the practice of biological control and give better insight into how parasitoid species may coexist in diverse environments.展开更多
基金Acknowledgments This research was financially supported by the Na- tional Natural Science Foundation of China （30930062, 31301726） and the National Basic Research Program of China （2013CBl27605）. The authors thank Steven A. Juliano （Illinois State University） and Xiang-Hong Yu （Graduate School of Chinese Academy of Agricultural Sciences） for statistical assistance.
文摘The functional responses of two parasitoids, Eretmocerus hayati Zolnerowich ＆ Rose and Encarsia sophia Girault ＆ Dodd, of whitefly Bemisia tabaci Gennadius Middle East-Asia Minor 1 were studied under laboratory conditions. In addition, the influence of host density and host stage on the competitive interactions between the two parasitoids, and biological control effect on whitefly were evaluated. In the functional response study, adult parasitoids were tested individually, with a conspecific or heterospecific competitor. Both Er. hayati and En. sophia exhibited a type II response to increasing host density, whether a conspecific or heterospecific competitor was present or not. Difference of searching rates and handling times between treatments suggested interference interactions existed between two parasitoid species. In the host stage preference study, two parasitoid species were jointly tested. Er. hayati had a competitive advantage over En. sophia when provided young host instars （first and second instar）, whereas no advantage was found on old host instars （third and fourth instar）. The biological control effect ofEr hayati and En. sophia in different introductions varied with host density. However, the effect of host instar on host mortality was not significant. These findings provide information for the practice of biological control and give better insight into how parasitoid species may coexist in diverse environments.
