Understanding the temperature affecting parasitic efficiency is critical to succeed in utilizing parasitoid as natural enemy in pest management. Laboratory studies were carried out to determine the effects of temperat...Understanding the temperature affecting parasitic efficiency is critical to succeed in utilizing parasitoid as natural enemy in pest management. Laboratory studies were carried out to determine the effects of temperature on parasitoid preference of female Anagrus nilaparvatae Pang et Wang （Hymenoptera：Mymaridae） to the eggs of whitebacked planthopper （WBPH）, Sogatella furcifera Horváth and brown planthopper （BPH）, Nilaparvata lugens Stl to build a composite model describing changes in parasitic response along a temperature gradient （18, 22, 26, 30, 34°C）. The results showed that attack responses of A. nilaparvatae on WBPH and BPH were the best described by a Type II functional response. The two parameters, attack rates （a） and handling times （Th）, of A. nilaparvatae to both eggs were influenced by the temperature. The maximum attack rates to WBPH （1.235） and BPH （1.049） were at 26 and 34°C, respectively, and the shortest handling times to WBPH （0.063） and BPH （0.057） were at 30 and 26°C, respectively. However, the optimal temperature for parasitic efficiency of A. nilaparvatae to WBPH and BPH eggs was both at 26°C, which showed that the present microclimate temperature of the habitat in the paddyfield was beneficial to A. nilaparvatae and indicated that parasitic efficiency of A. nilaparvatae would be impaired by global warming.展开更多
Anagrus nilaparvatae is the dominant egg parasitoid of rice planthoppers and plays an important role in biological control. Symbiotic bacteria can significantly influence the development, survival, reproduction and po...Anagrus nilaparvatae is the dominant egg parasitoid of rice planthoppers and plays an important role in biological control. Symbiotic bacteria can significantly influence the development, survival, reproduction and population differentiation of their hosts. To study the influence of temperature on symbiotic bacterial composition in the successive generations of A. nilaparvatae, A. nilaparvatae were raised under different constant temperatures of 22 °C, 25 °C, 28 °C, 31 °C and 34 °C. Polymerase chain reaction-denaturing gradient gel electrophoresis was used to investigate the diversity of symbiotic bacteria. Our results revealed that the endophytic bacteria of A. nilaparvatae were Pantoea sp., Pseudomonas sp. and some uncultured bacteria. The bacterial community composition in A. nilaparvatae significantly varied among different temperatures and generations, which might be partially caused by temperature, feeding behavior and the physical changes of hosts. However, the analysis of wsp gene showed that the Wolbachia in A. nilaparvatae belonged to group A, sub-group Mors and sub-group Dro. Sub-group Mors was absolutely dominant, and this Wolbachia composition remained stable in different temperatures and generations, except for the 3rd generation under 34 °C during which sub-group Dro became the dominant Wolbachia. The above results suggest that the continuous high temperature of 34 °C can influence the Wolbachia community composition in A. nilaparvatae.展开更多
What shapes the relative investment in reproduction versus survival of organisms is among the key questions in life history.Proovigenic insects mature all their eggs prior to emergence and are short lived,providing a ...What shapes the relative investment in reproduction versus survival of organisms is among the key questions in life history.Proovigenic insects mature all their eggs prior to emergence and are short lived,providing a unique opportunity to quantify their lifetime investments in the different functions.We investigated the initial eggloads and longevity of 2 proovigenic parasitoid wasps:Anagrus erythroneurae and Anagrus daanei,(Hymenoptera:Mymaridae)that develop within leafhopper eggs in both agricultural vineyards and natural riparian habitats in Northern California.We collected Vitis spp.leaves containing developing parasitoids from 3 natural sites(Knight Landing,American River and Putah Creek)and 3 agricultural vineyards(Solano Farm,Davis Campus and Village Homes).We recorded eggloads at parasitoid emergence and female parasitoid longevity with or without honey-feeding.Theory predicts that parasitoids from vineyards(where hosts are abundant)would have higher initial eggloads and lower longevity compared with parasitoids from riparian habitats(where hosts are scarce).Although host density and parasitoid eggloads were,indeed,higher in vineyards than in riparian habitats,parasitoid longevity did not follow the predicted pattern.Longevity without feeding differed among field sites,but it was not affected by habitat type(natural vs agricultural),whereas longevity with feeding was not significantly affected by any of the examined factors.Moreover,longevity was positively,rather than negatively,correlated with eggloads at the individual level,even after correcting for parasitoid body size.The combined results suggest a more complex allocation mechanism than initially predicted,and the possibility of variation in host quality that is independent of size.展开更多
基金supported by the Special Fund for Agro-Scientific Research in the Public Interest, China (200903051 and 200803003)
文摘Understanding the temperature affecting parasitic efficiency is critical to succeed in utilizing parasitoid as natural enemy in pest management. Laboratory studies were carried out to determine the effects of temperature on parasitoid preference of female Anagrus nilaparvatae Pang et Wang （Hymenoptera：Mymaridae） to the eggs of whitebacked planthopper （WBPH）, Sogatella furcifera Horváth and brown planthopper （BPH）, Nilaparvata lugens Stl to build a composite model describing changes in parasitic response along a temperature gradient （18, 22, 26, 30, 34°C）. The results showed that attack responses of A. nilaparvatae on WBPH and BPH were the best described by a Type II functional response. The two parameters, attack rates （a） and handling times （Th）, of A. nilaparvatae to both eggs were influenced by the temperature. The maximum attack rates to WBPH （1.235） and BPH （1.049） were at 26 and 34°C, respectively, and the shortest handling times to WBPH （0.063） and BPH （0.057） were at 30 and 26°C, respectively. However, the optimal temperature for parasitic efficiency of A. nilaparvatae to WBPH and BPH eggs was both at 26°C, which showed that the present microclimate temperature of the habitat in the paddyfield was beneficial to A. nilaparvatae and indicated that parasitic efficiency of A. nilaparvatae would be impaired by global warming.
基金supported jointly by the National Basic Research Program of China (Grant No. 2010CB126202)the Agro-Industry R&D Special Fund of China (Grant No. 200903051)Zhejiang Provincial Key Project on Agricultural Science of China (Grant No. 2011C12022)
文摘Anagrus nilaparvatae is the dominant egg parasitoid of rice planthoppers and plays an important role in biological control. Symbiotic bacteria can significantly influence the development, survival, reproduction and population differentiation of their hosts. To study the influence of temperature on symbiotic bacterial composition in the successive generations of A. nilaparvatae, A. nilaparvatae were raised under different constant temperatures of 22 °C, 25 °C, 28 °C, 31 °C and 34 °C. Polymerase chain reaction-denaturing gradient gel electrophoresis was used to investigate the diversity of symbiotic bacteria. Our results revealed that the endophytic bacteria of A. nilaparvatae were Pantoea sp., Pseudomonas sp. and some uncultured bacteria. The bacterial community composition in A. nilaparvatae significantly varied among different temperatures and generations, which might be partially caused by temperature, feeding behavior and the physical changes of hosts. However, the analysis of wsp gene showed that the Wolbachia in A. nilaparvatae belonged to group A, sub-group Mors and sub-group Dro. Sub-group Mors was absolutely dominant, and this Wolbachia composition remained stable in different temperatures and generations, except for the 3rd generation under 34 °C during which sub-group Dro became the dominant Wolbachia. The above results suggest that the continuous high temperature of 34 °C can influence the Wolbachia community composition in A. nilaparvatae.
文摘What shapes the relative investment in reproduction versus survival of organisms is among the key questions in life history.Proovigenic insects mature all their eggs prior to emergence and are short lived,providing a unique opportunity to quantify their lifetime investments in the different functions.We investigated the initial eggloads and longevity of 2 proovigenic parasitoid wasps:Anagrus erythroneurae and Anagrus daanei,(Hymenoptera:Mymaridae)that develop within leafhopper eggs in both agricultural vineyards and natural riparian habitats in Northern California.We collected Vitis spp.leaves containing developing parasitoids from 3 natural sites(Knight Landing,American River and Putah Creek)and 3 agricultural vineyards(Solano Farm,Davis Campus and Village Homes).We recorded eggloads at parasitoid emergence and female parasitoid longevity with or without honey-feeding.Theory predicts that parasitoids from vineyards(where hosts are abundant)would have higher initial eggloads and lower longevity compared with parasitoids from riparian habitats(where hosts are scarce).Although host density and parasitoid eggloads were,indeed,higher in vineyards than in riparian habitats,parasitoid longevity did not follow the predicted pattern.Longevity without feeding differed among field sites,but it was not affected by habitat type(natural vs agricultural),whereas longevity with feeding was not significantly affected by any of the examined factors.Moreover,longevity was positively,rather than negatively,correlated with eggloads at the individual level,even after correcting for parasitoid body size.The combined results suggest a more complex allocation mechanism than initially predicted,and the possibility of variation in host quality that is independent of size.
