Ross Perran A, Hoffmann Ary A
Pest and Environmental Adaptation Research Group, School of BioSciences, Bio21 Institute, The University of Melbourne, Victoria 3010, Australia.
Insects. 2018 Jun 30;9(3):78. doi: 10.3390/insects9030078.
mosquitoes infected with the Mel strain of are being deployed to control the spread of arboviruses around the world through blockage of viral transmission. Blockage by in some scenarios may be affected by the susceptibility of Mel to cyclical heat stress during mosquito larval development. We therefore evaluated the potential to generate a heat-resistant strain of Mel in through artificial laboratory selection and through exposure to field temperatures across multiple generations. To generate an artificially selected strain, Mel-infected females reared under cyclical heat stress were crossed to Mel-infected males reared at 26 °C. The low proportion of larvae that hatched founded the next generation, and this process was repeated for eight generations. The Mel heat-selected strain (Mel-HS) was similar to Mel (unselected) in its ability to induce cytoplasmic incompatibility and restore compatibility when larvae were reared under cyclical heat stress, but Mel-HS adults exhibited reduced densities at 26 °C. To investigate the effects of field exposure, we compared the response of Mel-infected collected from Cairns, Australia where the infection has been established for seven years, to a Mel-infected population maintained in the laboratory for approximately 60 generations. Field and laboratory strains of Mel did not differ in their response to cyclical heat stress or in their phenotypic effects at 26 °C. The capacity for the Mel infection in to adapt to high temperatures therefore appears limited, and alternative strains may need to be considered for deployment in environments where high temperatures are regularly experienced in mosquito breeding sites.
感染了Mel品系的蚊子正被用于通过阻断病毒传播来控制虫媒病毒在全球的传播。在某些情况下，Mel的阻断作用可能会受到蚊子幼虫发育期间Mel对周期性热应激敏感性的影响。因此，我们通过人工实验室选择以及让其在多代中暴露于田间温度，评估了培育Mel耐热品系的潜力。为了培育一个人工选择的品系，将在周期性热应激下饲养的感染Mel的雌性蚊子与在26℃饲养的感染Mel的雄性蚊子杂交。孵化出的幼虫比例很低，它们构成了下一代，这个过程重复了八代。Mel热选品系（Mel-HS）在诱导细胞质不相容性以及当幼虫在周期性热应激下饲养时恢复相容性的能力方面与Mel（未选择）相似，但Mel-HS成虫在26℃时的密度较低。为了研究田间暴露的影响，我们比较了从澳大利亚凯恩斯收集的感染Mel的蚊子（该感染已存在七年）与在实验室中维持了约60代的感染Mel的种群的反应。Mel的田间品系和实验室品系在对周期性热应激的反应或在26℃时的表型效应方面没有差异。因此，蚊子中Mel感染适应高温的能力似乎有限，在蚊子繁殖地经常经历高温的环境中部署时可能需要考虑使用替代品系。
