Quantifying Variation in the Ability of Yeasts to Attract Drosophila melanogaster

Abstract

Yeasts that invade and colonise fruit significantly enhance the volatile chemical diversity of this ecosystem. These modified bouquets are thought to be more attractive to Drosophila flies than the fruit alone, but the variance of attraction in natural yeast populations is uncharacterised. Here we investigate how a range of yeast isolates affect the attraction of female D. melanogaster to fruit in a simple two choice assay comparing yeast to sterile fruit. Of the 43 yeast isolates examined, 33 were attractive and seven repellent to the flies. The results of isolate-versus-isolate comparisons provided the same relative rankings. Attractiveness varied significantly by yeast, with the strongly fermenting Saccharomyces species generally being more attractive than the mostly respiring non- Saccharomyces species (P = 0.0035). Overall the habitat (fruit or other) from which the isolates were directly sampled did not explain attraction (P = 0.2352). However, yeasts isolated from fruit associated niches were more attractive than those from non-fruit associated niches (P = 0.0188) regardless of taxonomic positioning. These data suggest that while attractiveness is primarily correlated with phylogenetic status, the ability to attract Drosophila is a labile trait among yeasts that is potentially associated with those inhabiting fruit ecosystems. Preliminary analysis of the volatiles emitted by four yeast isolates in grape juice show the presence/absence of ethanol and acetic acid were not likely explanations for the observed variation in attraction. These data demonstrate variation among yeasts for their ability to attract Drosophila in a pattern that is consistent with the hypothesis that certain yeasts are manipulating fruit odours to mediate interactions with their Drosophila dispersal agent.

Metabolite exchange between microbiome members produces compounds that influence Drosophila behavior

“…Drosophila ingests microbiome members from the environment (e.g., fermenting fruit, [Camargo and Phaff, 1957; Barata et al, 2012; Erkosar et al, 2013; Blum et al, 2013; Broderick et al, 2014]), a behavior posited as a mechanism for Drosophila to select, acquire, and maintain its microbiome (Broderick and Lemaitre, 2012; Blum et al, 2013). Drosophila behavior toward environmental microorganisms has focused on yeasts (Becher et al, 2012; Christiaens et al, 2014; Schiabor et al, 2014; Palanca et al, 2013; Venu et al, 2014). Yeasts attract Drosophila via ester production (Christiaens et al, 2014; Schiabor et al, 2014), induce Drosophila egg-laying behavior (Becher et al, 2012), and are vital for larval development (Becher et al, 2012).…”

Physiological and behavioral responses in Drosophila melanogaster to odorants present at different plant maturation stages

“…The observation that in D. melanogaster most olfactory receptors are responsive to fruit odors [3] is consistent with the ecology of a species that feeds, mates and oviposits on overripe fruit. While many studies have investigated the responses of fruit flies to compounds associated with fruit fermentation [19,20,36], including yeast [32,37], less attention has been devoted to compounds associated with the early stages of fruit maturation. This information is important to understand the natural history of drosophilids and how they can occupy different ecological niches [38].…”

Olfaction: Smells Like Fly Food

“…The compounds found in the headspace of rotting fruit attract fruit flies and give them information about the state of microbial colonization [5,6]. Several studies have now established that volatile compounds produced by fruit and yeasts play an important role as signals for the flies, attracting adults to congregate, mate and lay eggs on fruit [5,[7][8][9].…”

“…Yeasts themselves produce many volatile compounds that flies find attractive [5,9]. When HCAs were added to media, the yeast species Brettanomyces bruxellensis produced two new compounds, the ethylphenols 4-ethylguiacol and 4-ethylphenol.…”

“…To begin to place these observations in a behavioral context, Jay et al [1] focused on an evolutionarily conserved group of dopaminergic diencephalospinal neurons (DDNs) in the forebrain, which provide the sole source of spinal dopamine not only in zebrafish [9,10], but also in mammals [11]. The authors took advantage of an enhancer trap transgenic line of zebrafish, Tg(ETvmat2:GFP), in which these neurons are labeled by green fluorescent protein (GFP) [12].…”