Altered diversity of bacterial communities in two Drosophila species under laboratory conditions and lead exposure

Abstract

The composition of microbiota affects different traits of Drosophila throughout its life cycle and represents an important part of the adaptive response to environmental changes, such as increased levels of accumulated heavy metals in their habitats. We investigated the effects of lead added to the feeding substrate on the microbiota diversity in the fruit flies, Drosophila melanogaster and Drosophila subobscura. We compared the bacterial diversity of wild-caught flies and their progeny reared under standard laboratory conditions. We analyzed the shifts in bacterial diversity in the experimental groups of flies reared for 13 generations on standard and lead(II) acetate (Pb(CH3COO)2), Pb acetate-saturated substrates. Identification of the main bacterial genera was performed by next-generation sequencing (NGS) of the V3-V4 variable regions of the 16S rRNA gene. Results indicate significant species-specific differences in bacterial composition between natural and laboratory populations, and between the substrates. Diversity increased in both species under prolonged exposure to lead-polluted substrate, suggesting a potential adaptive response to an environmental stress.

Life History Traits in Two Drosophila Species Differently Affected by Microbiota Diversity under Lead Exposure

“…Comparing the results obtained from the composition of microbiota and life history traits of two Drosophila species reared on different substrates, several potential cause-andeffect relationships were discovered. The overall microbial diversity and evenness in D. subobscura reared in the laboratory was lower than in D. melanogaster, as in our previous study which was done only on the Kalna population [5]. With the addition of the Slanka-…”

“…The results obtained in our previous study suggested the difference in shifts of microbiota composition between natural populations of two Drosophila species under laboratory conditions on standard and lead-saturated substrate after 13 generations [5]. In the present paper we investigate the microbiota of the same lab-reared Drosophila species (D. melanogaster and D. subobscura), but from each of the two distinct localities on standard and lead-saturated substrate after an additional 22 generations (35 in total).…”

“…Our previous research suggested that bacterial diversity increased in two Drosophila species after extended exposure to a lead-saturated substrate. This increase in bacterial diversity underlined certain bacterial genera, such as Komagataeibacter and Acetobacter, that could be good lead-tolerant members of microbiota [5].…”

“…Both species were maintained at 19 • C; D. melanogaster is successfully reared at 19-25 • C, while for D. subobscura 19 • C is the optimal temperature. Since D. subobscura generally does not lay eggs in laboratory conditions without dry yeast powder, the powder was added to the substrate surface in both species in order to maintain equal conditions (detailed description is given in Beribaka et al [5]). For the same purposes, the Nipagin, which was reported to modify the microbiota associated with the flies to some extent, was added in all substrates in the same amount at the same time [19].…”

“…Drosophila hosts only a small number of bacterial populations in its gut, but includes species present in the human microbiota as well. Drosophila gut microbiota in laboratory is represented by a low-diversity bacterial community [4,5], but it has great implications on its overall health. The gut microbiome of Drosophila contributes to a variety of host traits, such as innate immunity [6], lifespan [7][8][9], nutrition and reproduction [10] and behavior [11,12].…”