Symbiotic bacteria attenuate Drosophila oviposition repellence to alkaline through acidification

Abstract

Metazoans harbor a wealth of symbionts that are ever-changing the environment by taking up resources and/or excreting metabolites. One such common environmental modification is a change in pH. Conventional wisdom holds that symbionts facilitate the survival and production of their hosts in the wild, but this notion lacks empirical evidence. Here, we report that symbiotic bacteria in the genus Enterococcus attenuate the oviposition avoidance of alkaline environments in Drosophila. We studied the effects of alkalinity on oviposition preference for the first time, and found that flies are robustly disinclined to oviposit on alkali-containing substrates. This innate repulsion to alkaline environments is explained, in part, by the fact that alkalinity compromises the health and lifespan of both offspring and parent Drosophila. Enterococcus dramatically diminished or even completely reversed the ovipositional avoidance of alkalinity in Drosophila. Mechanistically, Enterococcus generate abundant lactate during fermentation, which neutralizes the residual alkali in an egg-laying substrate. In conclusion, Enterococcus protects Drosophila from alkali stress by acidifying the ovipositional substrate, and ultimately improves the fitness of the Drosophila population. Our results demonstrate that symbionts are profound factors in the Drosophila ovipositional decision, and extend our understanding of the intimate interactions between Drosophila and their symbionts.

Alkaline taste sensation through the alkaliphile chloride channel in Drosophila

“…Flies fed moderately alkaline diets display significantly reduced lifespan and survivability 80 . Furthermore, chronic exposure to a highly alkaline environment impairs development, shortens lifespan, and causes lethality 81 . Consequently, female flies robustly avoid alkaline substrates when selecting a location to deposit eggs 81 .…”

“…Furthermore, chronic exposure to a highly alkaline environment impairs development, shortens lifespan, and causes lethality 81 . Consequently, female flies robustly avoid alkaline substrates when selecting a location to deposit eggs 81 . Taken together, alkaline pH sensation serves as an essential self-protection strategy that enables flies and other animal species to effectively avoid toxic environments during food foraging and habitat selection.…”

Gut bacterium promotes host fitness in special ecological niche by affecting sugar metabolism in Drosophila suzukii

“…Axenic (i.e., microbiota-free) R. ferrugineus recolonized by Escherichia cloacae could significantly increase their level of development and the levels of hemolymph protein and glucose (Habineza et al, 2019). Axenic Drosophila flies exhibited prolonged longevity and elevated glucose and triglyceride contents, whereas in axenic Drosophila flies colonized with gut microbiota, the glucose level was restored to that of conventional flies (Newell & Douglas, 2014;Huang & Douglas, 2015;Liu et al, 2021). In this study, the survival rates of larvae and adults, their body sizes, and their longevity were increased in D. suzukii colonized with K. oxytoca alone, compared with axenic D. suzukii (the NB strain).…”

Gut bacteria promotes host fitness to special ecological niche by regulating sugar metabolism in Drosophila suzukii

“…Axenic R. ferrugineus introduced by E. cloacae (Jordan 1890), could signi cantly increase their level of development and the content of hemolymph protein and glucose (Habineza et al 2019). Axenic (microbiota-free) Drosophila ies exhibited prolonged longevity and elevated glucose and triglyceride contents, while the glucose content was recapitulated to the level of conventional ies in axenic Drosophila ies colonized with gut microbiota (Newell and Douglas 2014; Huang and Douglas 2015; Liu et al 2021). In this study, the survival rate of larvae and adults, body size and the longevity were increased in D. suzukii single-colonized with K. oxytoca compared to axenic D. suzukii (NB strain).…”