School of BioSciences, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia.
Section for Bioscience and Engineering, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark.
Environ Microbiol. 2024 Apr;26(4):e16609. doi: 10.1111/1462-2920.16609.
The susceptibility of insects to rising temperatures has largely been measured by their ability to survive thermal extremes. However, the capacity for maternally inherited endosymbionts to influence insect heat tolerance has been overlooked. Further, while some studies have addressed the impact of heat on traits like fertility, which can decline at temperatures below lethal thermal limits, none have considered the impact of endosymbionts. Here, we assess the impact of three Wolbachia strains (wRi, wAu and wNo) on the survival and fertility of Drosophila simulans exposed to heat stress during development or as adults. The effect of Wolbachia infection on heat tolerance was generally small and trait/strain specific. Only the wNo infection significantly reduced the survival of adult males after a heat shock. When exposed to fluctuating heat stress during development, the wRi and wAu strains reduced egg-to-adult survival but only the wNo infection reduced male fertility. Wolbachia densities of all three strains decreased under developmental heat stress, but reductions occurred at temperatures above those that reduced host fertility. These findings emphasize the necessity to account for endosymbionts and their effect on both survival and fertility when investigating insect responses to heat stress.
昆虫对温度升高的敏感性在很大程度上是通过它们在极端温度下生存的能力来衡量的。然而，人们忽视了母体遗传共生体影响昆虫耐热能力的能力。此外，虽然一些研究已经探讨了热量对生育等特征的影响，这些特征在低于致死热极限的温度下会下降，但没有研究考虑共生体的影响。在这里，我们评估了三种沃尔巴克氏体菌株（wRi、wAu 和 wNo）对发育过程中或成年后暴露于热应激的果蝇 simulans 的生存和生育能力的影响。沃尔巴克氏体感染对耐热性的影响通常很小且具有特征/菌株特异性。只有 wNo 感染显著降低了热激后雄性成虫的存活率。当在发育过程中暴露于波动的热应激时，wRi 和 wAu 菌株降低了卵到成虫的存活率，但只有 wNo 感染降低了雄性的生育能力。所有三种菌株的沃尔巴克氏体密度在发育热应激下下降，但减少发生在降低宿主生育能力的温度以上。这些发现强调了在研究昆虫对热应激的反应时，必须考虑共生体及其对生存和生育能力的影响。
