Are Drosophila preferences for yeasts stable or contextual?

Abstract

Whether there are general mechanisms, driving interspecific chemical communication is uncertain. Saccharomycetaceae yeast and Drosophila fruit flies, both extensively studied research models, share the same fruit habitat, and it has been suggested their interaction comprises a facultative mutualism that is instigated and maintained by yeast volatiles. Using choice tests, experimental evolution, and volatile analyses, we investigate the maintenance of this relationship and reveal little consistency between behavioral responses of two isolates of sympatric Drosophila species. While D. melanogaster was attracted to a range of different Saccharomycetaceae yeasts and this was independent of fruit type, D. simulans preference appeared specific to a particular S. cerevisiae genotype isolated from a vineyard fly population. This response, however, was not consistent across fruit types and is therefore context‐dependent. In addition, D. simulans attraction to an individual S. cerevisiae isolate was pliable over ecological timescales. Volatile candidates were analyzed to identify a common signal for yeast attraction, and while D. melanogaster generally responded to fermentation profiles, D. simulans preference was more discerning and likely threshold‐dependent. Overall, there is no strong evidence to support the idea of bespoke interactions with specific yeasts for either of these Drosophila genotypes. Rather the data support the idea Drosophila are generally adapted to sense and locate fruits infested by a range of fungal microbes and/or that yeast– Drosophila interactions may evolve rapidly.

Yeast Species, Strains, and Growth Media Mediate Attraction of Drosophila suzukii (Diptera: Drosophilidae)

“…Clearly, growth medium can have a marked effect on the attractiveness of fermenting preparations of yeasts [17]. Appropriate mixtures of nutrients at suitable concentrations are critical for high biomass and the production of volatile compounds in yeasts [33].…”

“…A clear association has been established between some yeasts of the family Saccharomycetaceae and drosophilids because (i) yeasts constitute a key nutritional source that improves fitness, sexual maturation, egg production, and courtship performance of adult flies and (ii) dispersal of yeasts by adult flies increases the dissemination and genetic diversity of these microbes [8,9,10,11,12,13]. Indeed, many species of Drosophila are attracted to volatile compounds produced by fermenting yeasts, or bacterial metabolites of these compounds [14,15,16,17], a feature that could be exploited for the development of effective and selective attractants for use in crop settings. Of the yeast species associated with Drosophila, the majority belong to the genera Saccharomyces, Hanseniaspora , Candida, and Pichia , all within the family Saccharomycetaceae [9,12,18,19].…”

“…Attraction of adult drosophilids to yeasts is likely to depend on the yeast species [24], the origin of each yeast strain [15], and the growth medium [17,25]. Consequently, in the present study we addressed three issues.…”

Saccharomyces cerevisiae – Insects Association: Impacts, Biogeography, and Extent

“…Interestingly, species-specific attractions have been observed. While D. melanogaster is attracted by S. cerevisiae, D. simulans is indifferent to this yeast species (Gunther et al, 2019). At the same time, D. melanogaster and the subgenus Sophophora are preferentially attracted to baits seeded with Hanseniaspora uvarum than to S. cerevisiae and forest-dwelling Drosophila species (e.g., D. tripunctata and the guarani group) are more attracted by S. cerevisiae than by H. uvarum (Batista et al, 2017).…”

Separate and combined Hanseniaspora uvarum and Metschnikowia pulcherrima metabolic volatiles are attractive to Drosophila suzukii in the laboratory and field

“…Lewis and Hamby 12 showed that while D. suzukii larvae exhibited a preference for H. uvarum over S. cerevisiae yeast, this preference did not translate to more rapid development time 12 . Given the apparent role of yeast in Drosophila fitness it is reasonable to suggest that natural selection will have operated on Drosophila traits that increase the probability of locating yeast laden-fruits 14 , 15 . In line with this prediction Drosophila females prefer to oviposit on yeast-colonised fruit 13 , and yeast metabolic volatiles act as cues for Drosophila to locate fruit with yeasts (e.g.…”