Differential Impacts of Yeasts on Feeding Behavior and Development in Larval Drosophila suzukii (Diptera:Drosophilidae)

Margaret T Lewis,Kelly A Hamby

doi:10.1038/s41598-019-48863-1

Margaret T Lewis, Kelly A Hamby

Open Access

https://doi.org/10.1038/s41598-019-48863-1

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Journal: Scientific Reports	Publication Date: Sep 16, 2019
Citations: 37	License type: open-access

Affiliation: University of Maryland, College Park

Abstract

Larval Drosophila encounter and feed on a diverse microbial community within fruit. In particular, free-living yeast microbes provide a source of dietary protein critical for development. However, successional changes to the fruit microbial community may alter host quality through impacts on relative protein content or yeast community composition. For many species of Drosophila, fitness benefits from yeast feeding vary between individual yeast species, indicating differences in yeast nutritional quality. To better understand these associations, we evaluated how five species of yeast impacted feeding preference and development in larval Drosophila suzukii. Larvae exhibited a strong attraction to the yeast Hanseniaspora uvarum in pairwise yeast feeding assays. However, larvae also performed most poorly on diets containing H. uvarum, a mismatch in preference and performance that suggests differences in yeast nutritional quality are not the primary factor driving larval feeding behavior. Together, these results demonstrate that yeast plays a critical role in D. suzukii’s ecology and that larvae may have developed specific yeast associations. Further inquiry, including systematic comparisons of Drosophila larval yeast associations more broadly, will be necessary to understand patterns of microbial resource use in larvae of D. suzukii and other frugivorous species.

Highlights

This latter category of nutritional interactions is well documented within the genus Drosophila (Diptera: Drosophilidae)
This result is consistent with previous reports that H. uvarum predominates the culturable larval gut microbial community in geographically distant populations of D. suzukii[38,39] and to the best of our knowledge, is the first evidence that larval D. suzukii exhibit feeding preferences for specific yeast species
Our studies suggest that larval feeding is not random; despite being confined to a single fruit throughout development, larval D. suzukii appear to deliberately seek out and feed on H. uvarum, indicating that there may be an association between these two organisms

Summary

Introduction

This latter category of nutritional interactions is well documented within the genus Drosophila (Diptera: Drosophilidae). For many frugivorous species of Drosophila, yeasts provide a source of dietary protein otherwise absent from ripening fruit, a carbohydrate-rich resource[11]. When reared on intermediate protein diets (e.g. 1:2 or 1:4 P:C ratio), larval D. suzukii exhibit faster development times, larger adult body sizes, and higher female ovariole numbers relative to Drosophila biarmipes Malloch[19], a close relative of D. suzukii that colonizes decaying fruit. The microbiota/ nutrient-rich diet combination does not appear to harm D. melanogaster; comparisons between amicrobial larvae and larvae containing their natural microbiota found no differences in larval development time[24]. These differences likely reflect adaptations by D. suzukii larvae to relatively nutrient-poor ripening fruit. In addition to variably impacting larval development, it is possible that these nutritional differences influence larval feeding behavior

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