Physiological responses of insects to microbial fermentation products: Insights from the interactions between Drosophila and acetic acid

• Published in: Journal of insect physiology Vol. 106; no. Pt 1; pp. 13 - 19
• Main Authors: Kim, Geonho, Huang, Jia Hsin, McMullen, John G., Newell, Peter D., Douglas, Angela E.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-04-2018
• Subjects: Acetic acid; Acid load; Drosophila; Fermentation products; Gut microbiota; Larval development; Microbiome; Gut microbiota; Acid load; Drosophila; Acetic acid; Larval development; Fermentation products; Microbiome
• ISSN: 0022-1910; 1879-1611
• DOI: 10.1016/j.jinsphys.2017.05.005

[Display omitted]
•Acetic acid is a fermentation product of gut bacteria in Drosophila.•Acetic acid stimulates egg deposition and ovipositional preference in Drosophila.•Acetic acid promotes feeding but prolongs development of larval Drosophila.•High acetic acid concentrations suppress populations of gut bacterium Acetobacter.•Acetic acid may be a cue for microbial communities that promote Drosophila nutrition.
Acetic acid is a fermentation product of many microorganisms, including some that inhabit the food and guts of Drosophila. Here, we investigated the effect of dietary acetic acid on oviposition and larval performance of Drosophila. At all concentrations tested (0.34–3.4%), acetic acid promoted egg deposition by mated females in no-choice assays; and females preferred to oviposit on diet with acetic acid relative to acetic acid-free diet. However, acetic acid depressed larval performance, particularly extending the development time of both larvae colonized with the bacterium Acetobacter pomorum and axenic (microbe-free) larvae. The larvae may incur an energetic cost associated with dissipating the high acid load on acetic acid-supplemented diets. This effect was compounded by suppressed population growth of A. pomorum on the 3.4% acetic acid diet, such that the gnotobiotic Drosophila on this diet displayed traits characteristic of axenic Drosophila, specifically reduced developmental rate and elevated lipid content. It is concluded that acetic acid is deleterious to larval Drosophila, and hypothesized that acetic acid may function as a reliable cue for females to oviposit in substrates bearing microbial communities that promote larval nutrition.