Chemicals and chemoreceptors: ecologically relevant signals driving behavior in Drosophila

Ana Depetris-Chauvin,Diego Galagovsky,Yael Grosjean

doi:10.3389/fevo.2015.00041

Abstract

Insects encounter a vast repertoire of chemicals in their natural environment, which can signal positive stimuli like the presence of a food source, a potential mate, or a suitable oviposition site as well as negative stimuli such as competitors, predators, or toxic substances reflecting danger. The presence of specialized chemoreceptors like taste and olfactory receptors allow animals to detect chemicals at short and long distances and accordingly, trigger proper behaviors towards these stimuli. Since the first description of olfactory and taste receptors in Drosophila fifteen years ago, our knowledge on the identity, properties, and function of specific chemoreceptors has increased exponentially. In the last years, multidisciplinary approaches combining genetic tools with electrophysiological techniques, behavioral recording, evolutionary analysis, and chemical ecology studies are shedding light on our understanding on the ecological relevance of specific chemoreceptors for the survival of Drosophila in their natural environment. In this review we discuss the current knowledge on chemoreceptors of both the olfactory and taste systems of the fruitfly. We focus on the relevance of particular receptors for the detection of ecologically relevant cues such as pheromones, food sources, and toxic compounds, and we comment on the behavioral changes that the detection of these chemicals induce in the fly. In particular, we give an updated outlook of the chemical communication displayed during one of the most important behaviors for fly survival, the courtship behavior. Finally, the ecological relevance of specific chemicals can vary depending on the niche occupied by the individual. In that regard, in this review we also highlight the contrast between adult and larval systems and we propose that these differences could reflect distinctive requirements depending on the change of ecological niche occupied by Drosophila along its life cycle.

Highlights

Chemoreception is defined as the physiological response to a chemical stimulus
This definition might not be suitable for aquatic environments where solubility instead of volatility is the determinant factor for long-distance transport of molecules (Mollo et al, 2014)
Several ppk channels are expressed in taste neurons where they are required for relevant taste modalities such as low-salt detection (Liu et al, 2003b) and intraspecific chemical communication in larvae (Mast et al, 2014), and water perception (Cameron et al, 2010) and chemical communication during courtship in adults (Liu et al, 2012; Lu et al, 2012; Starostina et al, 2012; Thistle et al, 2012; Toda et al, 2012; Vijayan et al, 2014)

Summary

Introduction

Chemoreception is defined as the physiological response to a chemical stimulus. Depending on the spatial scale, a classical division exists between olfaction and taste chemoreception. Several ppk channels are expressed in taste neurons where they are required for relevant taste modalities such as low-salt detection (Liu et al, 2003b) and intraspecific chemical communication in larvae (Mast et al, 2014), and water perception (Cameron et al, 2010) and chemical communication during courtship in adults (Liu et al, 2012; Lu et al, 2012; Starostina et al, 2012; Thistle et al, 2012; Toda et al, 2012; Vijayan et al, 2014).

Results

Conclusion