Laboratory and wild Drosophila sechellia have conserved niche specialization phenotypes

Abstract

A major challenge to investigating the proximate causes of ecological adaptation is the difficulty of studying the phenotypes of organisms in their natural environments. By necessity, many studies seeking to determine the genetic and cellular basis of adaptation therefore investigate potentially adaptive phenotypes under laboratory conditions where organisms are more easily experimentally manipulated. For laboratory models, it remains unclear if organisms maintained long term under laboratory conditions are representative of relatives in their natural environment. In recent years, Drosophila sechellia, a specialist species endemic to the Seychelles, has emerged as a (neuro)genetic model for studying the molecular basis of ecological adaptation. A multitude of studies have investigated the genetic and cellular basis of various aspects of this species specialization in a laboratory setting. However, the vast majority of these studies use laboratory strains of D. sechellia that were collected many decades ago, and have been maintained under conditions very different from their natural niche. Thus, it remains unclear if and how these strains resemble their wild counterparts. Here, we compare the phenotypes of these laboratory strains with recently-collected wild D. sechellia to ask if laboratory strains display a loss or degradation of phenotypes potentially involved in their specialization resulting from their long-term laboratory maintenance. Across several behavioral and anatomical phenotypes, we find a high degree of similarity between wild-caught and laboratory-maintained strains. Our results suggest that studies of the molecular mechanisms underlying D. sechellias phenotypes associated with specialization are likely representative of the evolution of these flies in the wild.