Pest and Environmental Adaptation Research Group, Bio21 Institute and the School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia.
PLoS One. 2019 Nov 6;14(11):e0224268. doi: 10.1371/journal.pone.0224268. eCollection 2019.
Modified Aedes aegypti mosquitoes are being mass-reared for release in disease control programs around the world. Releases involving female mosquitoes rely on them being able to seek and feed on human hosts. To facilitate the mass-production of mosquitoes for releases, females are often provided blood through artificial membrane feeders. When reared across generations there is a risk that mosquitoes will adapt to feeding on membranes and lose their ability to feed on human hosts. To test adaptation to membrane feeding, we selected replicate populations of Ae. aegypti for feeding on either human arms or membrane feeders for at least 8 generations. Membrane-selected populations suffered fitness costs, likely due to inbreeding depression arising from bottlenecks. Membrane-selected females had higher feeding rates on membranes than human-selected ones, suggesting adaptation to membrane feeding, but they maintained their attraction to host cues and feeding ability on humans despite a lack of selection for these traits. Host-seeking ability in small laboratory cages did not differ between populations selected on the two blood sources, but membrane-selected females were compromised in a semi-field enclosure where host-seeking was tested over a longer distance. Our findings suggest that Ae. aegypti may adapt to feeding on blood provided artificially, but this will not substantially compromise field performance or affect experimental assessments of mosquito fitness. However, large population sizes (thousands of individuals) during mass rearing with membrane feeders should be maintained to avoid bottlenecks which lead to inbreeding depression.
经过改良的埃及伊蚊正在被大量繁殖，用于世界各地的疾病控制项目。涉及雌性蚊子的释放依赖于它们能够寻找并吸食人类宿主。为了便于大量生产用于释放的蚊子，通常通过人工膜饲养器为雌性蚊子提供血液。当经过多代繁殖时，蚊子有可能适应吸食膜并丧失吸食人类宿主的能力。为了测试对膜喂养的适应能力，我们选择了埃及伊蚊的重复种群，让它们至少连续 8 代吸食人类手臂或膜饲养器。膜选择种群遭受了适应成本，可能是由于瓶颈导致的近交衰退。膜选择的雌性蚊子在膜上的吸食率高于人类选择的蚊子，这表明它们对膜喂养的适应，但尽管缺乏对这些特征的选择，它们仍然保持对宿主线索的吸引力和在人类身上的吸食能力。在小实验室笼子中，从两种血液来源中选择的种群的宿主寻找能力没有差异，但在半野外围栏中，当测试更长距离的宿主寻找时，膜选择的雌性蚊子受到了损害。我们的研究结果表明，埃及伊蚊可能适应人工提供的血液喂养，但这不会严重影响野外表现或影响对蚊子适应性的实验评估。然而，在使用膜饲养器进行大规模繁殖时，应保持大量的种群规模（数千个个体），以避免导致近交衰退的瓶颈。
