Wolbachia infection negatively impacts Drosophila simulans heat tolerance in a strain‐ and trait‐specific manner

• Published in: Environmental microbiology Vol. 26; no. 4; pp. e16609 - n/a
• Main Authors: Ferguson, Liam F., Ross, Perran A., Heerwaarden, Belinda
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.04.2024; Wiley Subscription Services, Inc
• Subjects: Bacteria; Drosophila simulans; Endosymbionts; Fertility; Fruit flies; Heat; Heat shock; Heat stress; Heat tolerance; Infections; Insects; Strain; Survival; Temperature effects; Wolbachia
• ISSN: 1462-2912; 1462-2920
• 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. We assessed the impact of three Wolbachia strains on the survival and fertility of Drosophila simulans exposed to heat stress at different life stages and found that impacts were trait and strain specific. This highlights the need to account for endosymbionts when investigating the vulnerability of insects to climate change.