Adult Frass Provides a Pheromone Signature for Drosophila Feeding and Aggregation.

Ian W. Keesey,Bill S. Hansson,Sarah Koerte,Tom Retzke,Alexander Haverkamp,Markus Knaden

doi:10.1007/s10886-016-0737-4

Ian W. Keesey, Bill S. Hansson + Show 4 more

Open Access

https://doi.org/10.1007/s10886-016-0737-4

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Abstract

Adult Drosophila melanogaster locate food resources by using distinct olfactory cues that often are associated with the fermentation of fruit. However, in addition to being an odorous food source and providing a possible site for oviposition, fermenting fruit also provides a physical substrate upon which flies can attract and court a potential mate. In this study, we demonstrate that Drosophila adults are able to recruit additional flies to a food source by covering the exposed surface area with fecal spots, and that this recruitment is mediated via olfactory receptors (Ors). Analyses of the deposited frass material demonstrates that frass contains several previously studied pheromone components, such as methyl laurate (ML), methyl myristate (MM), methyl palmitate (MP), and 11-cis-vaccenyl acetate (cVA), in addition to several cuticular hydrocarbons (CHCs) that are known to be behaviorally active. Moreover, this study also demonstrates that adult feeding is increased in the presence of frass, although it appears that Ors are less likely to mediate this phenomenon. In summary, the frass deposited by the fly onto the fruit provides both pheromone and CHC cues that lead to increased feeding and aggregation in Drosophila. This research is the first step in examining Drosophila frass as an important chemical signature that provides information about both the sex and the species of the fly that generated the fecal spots.Electronic supplementary materialThe online version of this article (doi:10.1007/s10886-016-0737-4) contains supplementary material, which is available to authorized users.

Highlights

The pheromone system of Drosophila has been extensively studied, and previous research provides detailed information on the chemical identity of behaviorally relevant compounds that are generated by male and female flies (Auer and Benton 2016)
Surface washings of the fruit with and without deposited fecal spots, and solvent extractions of frass material alone revealed that several behaviorally important compounds were present in association with these fecal droplets, including the recently described pheromone components methyl laurate (ML), methyl myristate (MM), and methyl palmitate (MP), as well as their corresponding acids
In a trap assay, when Drosophila adults were allowed to choose between the odor of fruit alone, and the odor of fruit that had been in contact with other Drosophila, the majority of flies selected the fruit with previous exposure to conspecifics (Fig. 1c)

Summary

Introduction

The pheromone system of Drosophila has been extensively studied, and previous research provides detailed information on the chemical identity of behaviorally relevant compounds that are generated by male and female flies (Auer and Benton 2016). This broad area of research delves deeply into the neuronal mechanisms for both the detection and the decisionmaking of the fly in response to the presence of these pheromones, including the governance of complex multi-modal phenomena such as mate recognition and courtship. In the case of the boll weevil, the examination of frass provided the behavioral relevance and eventually the identification of specific pheromone components that were

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