title: Balancing selection shapes density-dependent foraging behaviour.
abstract: The optimal foraging strategy in a given environment depends on the number of competing individuals and their behavioural strategies. Little is known about the genes and neural circuits that integrate social information into foraging decisions. Here we show that ascaroside pheromones, small glycolipids that signal population density, suppress exploratory foraging in Caenorhabditis elegans, and that heritable variation in this behaviour generates alternative foraging strategies. We find that natural C. elegans isolates differ in their sensitivity to the potent ascaroside icas#9 (IC-asc-C5). A quantitative trait locus (QTL) regulating icas#9 sensitivity includes srx-43, a G-protein-coupled icas#9 receptor that acts in the ASI class of sensory neurons to suppress exploration. Two ancient haplotypes associated with this QTL confer competitive growth advantages that depend on ascaroside secretion, its detection by srx-43 and the distribution of food. These results suggest that balancing selection at the srx-43 locus generates alternative density-dependent behaviours, fulfilling a prediction of foraging game theory.
authors: Howard Hughes Medical Institute, Lulu and Anthony Wang Laboratory of Neural Circuits and Behavior, The Rockefeller University, New York, New York 10065, USA.
authors: Joshua S
authors: JS
authors: Greene
authors: Howard Hughes Medical Institute, Lulu and Anthony Wang Laboratory of Neural Circuits and Behavior, The Rockefeller University, New York, New York 10065, USA.
authors: Maximillian
authors: M
authors: Brown
authors: Howard Hughes Medical Institute, Lulu and Anthony Wang Laboratory of Neural Circuits and Behavior, The Rockefeller University, New York, New York 10065, USA.
authors: May
authors: M
authors: Dobosiewicz
authors: Howard Hughes Medical Institute, Lulu and Anthony Wang Laboratory of Neural Circuits and Behavior, The Rockefeller University, New York, New York 10065, USA.
authors: Itzel G
authors: IG
authors: Ishida
authors: Howard Hughes Medical Institute, Lulu and Anthony Wang Laboratory of Neural Circuits and Behavior, The Rockefeller University, New York, New York 10065, USA.
authors: Evan Z
authors: EZ
authors: Macosko
authors: Department of Chemistry, University of Florida, Gainesville, Florida 32611, USA.
authors: Xinxing
authors: X
authors: Zhang
authors: Department of Chemistry, University of Florida, Gainesville, Florida 32611, USA.
authors: Rebecca A
authors: RA
authors: Butcher
authors: School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
authors: Devin J
authors: DJ
authors: Cline
authors: School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
authors: Patrick T
authors: PT
authors: McGrath
authors: Howard Hughes Medical Institute, Lulu and Anthony Wang Laboratory of Neural Circuits and Behavior, The Rockefeller University, New York, New York 10065, USA.
authors: Cornelia I
authors: CI
authors: Bargmann
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism; D005247:Feeding Behavior / Q000187:drug effects; D005502:Food; D005716:Game Theory; D006239:Haplotypes; D006601:Hexoses / Q000378:metabolism / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D008297:Male; D010675:Pheromones / Q000378:metabolism / Q000494:pharmacology; D011156:Population Density; D040641:Quantitative Trait Loci; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D012641:Selection, Genetic; D011984:Sensory Receptor Cells / Q000378:metabolism; D012919:Social Behavior
chemical_list: D029742:Caenorhabditis elegans Proteins; D006601:Hexoses; D007211:Indoles; D010675:Pheromones; D043562:Receptors, G-Protein-Coupled; C000615783:SRX-43 protein, C elegans; C542711:indolecarboxyl-ascaroside C5