Genetic Architecture of Natural Variation Underlying Adult Foraging Behavior That Is Essential for Survival of Drosophila melanogaster

Abstract

Foraging behavior is critical for the fitness of individuals. However, the genetic basis of variation in foraging behavior and the evolutionary forces underlying such natural variation have rarely been investigated. We developed a systematic approach to assay the variation in survival rate in a foraging environment for adult flies derived from a wild Drosophila melanogaster population. Despite being such an essential trait, there is substantial variation of foraging behavior among D. melanogaster strains. Importantly, we provided the first evaluation of the potential caveats of using inbred Drosophila strains to perform genome-wide association studies on life-history traits, and concluded that inbreeding depression is unlikely a major contributor for the observed large variation in adult foraging behavior. We found that adult foraging behavior has a strong genetic component and, unlike larval foraging behavior, depends on multiple loci. Identified candidate genes are enriched in those with high expression in adult heads and, demonstrated by expression knock down assay, are involved in maintaining normal functions of the nervous system. Our study not only identified candidate genes for foraging behavior that is relevant to individual fitness, but also shed light on the initial stage underlying the evolution of the behavior.

The genetics of egg retention and fertilization success inDrosophila: One step closer to understanding the transition from facultative to obligate viviparity

“…This suggests that inbreeding depression is not a major contributor in the increase of the proportion of unfertilized eggs laid, similarly to another fitness trait–survival–measured in Lee et al. .…”

“…As we phenotyped inbred DGRP lines, a general concern could be that the observed high trait variation is the result of varying levels of inbreeding depression (Lee et al. ), and the implicated causative variants are deleterious mutations made homozygous through inbreeding. However, by comparing total residual heterozygosity of each line (from Table S7 in Lack et al.…”

“…However, by comparing total residual heterozygosity of each line (from Table S7 in Lack et al 2015) with fertilization success, we found no correlation between the level of inbreeding and our trait (ρ = -0.1442; P = 0.1749). This suggests that inbreeding depression is not a major contributor in the increase of the proportion of unfertilized eggs laid, similarly to another fitness trait-survivalmeasured in Lee et al 2017.…”

“…Coefficients of variation were intermediate for this trait (CV P = 37.304; CV G = 36.498) compared to CVs calculated for other phenotypes (Mackay et al 2008); the estimated CV G was higher than for life span (CV G = 18.693) or starvation resistance (CV G = 19.946), but lower than for chill coma recovery (CV G = 58.714) or copulation latency (CV G = 45.165). As we phenotyped inbred DGRP lines, a general concern could be that the observed high trait variation is the result of varying levels of inbreeding depression (Lee et al 2017), and the implicated causative variants are deleterious mutations made homozygous through inbreeding. However, by comparing total residual heterozygosity of each line (from Table S7 in Lack et al 2015) with fertilization success, we found no correlation between the level of inbreeding and our trait (ρ = -0.1442; P = 0.1749).…”

Identification of a genetic network for an ecologically relevant behavioural phenotype in Drosophila melanogaster

“…These include a potential cation transport function ( CG15270 ), transmembrane transporter activity ( Oatp74D ), a scaffolding protein regulating apicobasal polarity ( scrib ) and genes of as yet unclear function ( CG7567 and CG7029 ). scrib was found to be widespread expressed in olfactory organs and the central nervous system (Ganguly, Mackay, & Anholt, ), and has been reported to be associated with several behavioural traits in D. melanogaster , including olfactory behaviour (Ganguly et al, ), adult foraging (Lee et al, ) and sleep (Harbison et al, ).…”