Collective selection of food patches in Drosophila

Abstract

The fruit fly Drosophila melanogaster has emerged as a model organism for research on social interactions. Although recent studies have described how individuals interact on foods for nutrition and reproduction, the complex dynamics by which groups initially develop and disperse have received little attention. Here we investigated the dynamics of collective foraging decisions by D. melanogaster and their variation with group size and composition. Groups of adults and larvae facing a choice between two identical, nutritionally balanced food patches distributed themselves asymmetrically, thereby exploiting one patch more than the other. The speed of the collective decisions increased with group size, as a result of flies joining foods faster. However, smaller groups exhibited more pronounced distribution asymmetries than larger ones. Using computer simulations, we show how these non-linear phenomena can emerge from social attraction towards occupied food patches, whose effects add up or compete depending on group size. Our results open new opportunities for exploring complex dynamics of nutrient selection in simple and genetically tractable groups.

How social network structure affects decision-making inDrosophila melanogaster

“…The emergence of this collective behaviour is intriguing. Recent studies have shown that flies tend to show increased movement coordination and aggregation as a function of density and social encounters [35,36]. We previously found that the presence of informed flies within a group increases the number of interactions [21].…”

Drosophila females trade off good nutrition with high quality oviposition sites when choosing foods

“…Presumably, aggregation on foods mediated by social information transfer between foraging flies (e.g. phenomenal cues such as cis-11-vaccenyl acetate or sex-specific cuticular hydrocarbons) increased the accuracy of their oviposition decisions (Duménil et al, 2016;Lihoreau et al, 2016;Philippe et al, 2016), a well-known property of collective decision-making in animal groups (Couzin, 2009).…”

“…In nature, nutritional decisions can be complicated by several additional factors such as social information provided by other females (Battesti et al, 2012;Durisko et al, 2014;Lihoreau et al, 2016;Sarin and Dukas, 2009;Chabaud et al, 2009), competition (Eggert et al, 2008;Salomon et al, 2008), sexual interactions with males (Chapman and Partridge, 1996;Gorter et al, 2016) or the presence of beneficial microbial communities on foods (Venu et al, 2014;Wong et al, 2015). Thanks to their unique association with food as shelter, breeding sites and sources of nutrients, fruit flies hold considerable promise as model organisms with which to study these multi-level nutritional interactions within the extended integrative framework of nutritional ecology (Simpson et al, 2015a).…”

“…The flies were observed for 24 h. Top-view pictures of the test arena were taken every minute with a webcam (HD Webcam C270, Logitech, Romanel-sur-Morges, Switzerland) placed 150 mm above the setup and programmed with Zone Trigger (Omega Unfold, Montreal, QC, Canada). The number of flies on each food patch was counted on each of 80,640 images recorded using the 'analyse particles' tool in ImageJ (National Institutes of Health, Bethesda, MD, USA; for details of the image analysis procedure, see Lihoreau et al, 2016). At the end of the test, flies were removed and the number of eggs laid on each patch was counted.…”

Dissection of the Drosophila neuropeptide F circuit using a high-throughput two-choice assay

“…The behavior of flies can be significantly affected by group size, as has been shown in the context of CO 2 avoidance (27) and aggregation on a food resource (28). We therefore asked whether flies tested individually display preference for NPF neuron activation.…”