Characterization of increased mortality of Drosophila melanogaster exposed to sucrose-fermenting yeast

Authors: Shilman, Mikhail; Gee, Wai; Henderson, Thomas

Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/9/2024
Publication Date: 9/11/2024
Citation: Shilman, M.M., Gee, W.S., Henderson Ii, T.D. 2024. Characterization of increased mortality of Drosophila melanogaster exposed to sucrose-fermenting yeast. Biological Control. 198.Article 105618. https://doi.org/10.1016/j.biocontrol.2024.105618.
DOI: https://doi.org/10.1016/j.biocontrol.2024.105618

Interpretive Summary: This study explores the lethal impact of sucrose-fermenting Saccharomyces cerevisiae on adult fruit flies, challenging the conventional symbiotic view of their relationship. The research reveals consistent lethality across various S. cerevisiae strains and notes a lesser impact from another yeast, Pichia anomala. Factors influencing lethality include yeast concentration and temperature, with a notable decrease in sensitivity for males at lower temperatures and with higher sucrose levels in their diet. The findings offer insights into the intricate dynamics between fruit flies and yeast, presenting opportunities for targeted manipulation to mitigate agricultural pest issues.

Technical Abstract: Adult fruit flies are strongly attracted to odors emitted by the microbial fermentation of sugars in fruits. Such microbes, and particularly yeasts, also serve as an essential nutritional source for fruit flies and influence their reproduction and fecundity. Despite being known as natural symbionts, it was previously observed that sucrose-fermenting Saccharomyces cerevisiae can be lethal to Drosophila melanogaster. This study characterizes the conditions that affect the lethality of S. cerevisiae in fruit flies. We showed that the insecticidal pathogenicity of yeast was equal in five tested S. cerevisiae strains. Another yeast, Pichia anomala, killed fruit flies, although to a lesser degree than S. cerevisiae. Higher concentrations of yeast resulted in faster killing of fruit flies, although the killing rate was capped at two days of continuous exposure. Both sexes were similarly sensitive to yeast at 30, whereas males were less sensitive to yeast at 25 degrees Celsius. Higher sucrose amounts in food slightly decreased the sensitivity of male but not female flies to yeast. This study characterizes a relatively uncharted side of the intricate interaction between fruit flies and yeast and highlights the possibility for manipulation aimed at mitigating the agricultural impact of these pests.