The Effects of Selective History and Environmental Heterogeneity on Inbreeding Depression in Experimental Populations of Drosophila melanogaster

• Published in: The American naturalist Vol. 181; no. 4; pp. 532 - 544
• Main Authors: Long, Tristan A. F., Rowe, Locke, Agrawal, Aneil F.
• Format: Journal Article
• Language: English
• Published: Chicago, IL University of Chicago Press 01-04-2013; University of Chicago, acting through its Press
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Animals; Biological and medical sciences; Biological variation; Cadmium - toxicity; Drosophila melanogaster - drug effects; Drosophila melanogaster - genetics; Drosophila melanogaster - physiology; Environment; Female; Fundamental and applied biological sciences. Psychology; General aspects; Genetic Fitness; Genotype & phenotype; Inbreeding; Insects; Male; Selection, Genetic; Sodium Chloride - toxicity; Stress, Physiological; Time Factors; stress; inbreeding load; environmental heterogeneity; inbreeding depression; balancing selection; variance in fitness; Load; Inbreeding depression; Balancing; Insecta; Experimental study; Stress; Variance; Drosophilidae; Heterogeneity; Arthropoda; Inbreeding; Invertebrata; Drosophila melanogaster; Diptera; Fitness
• ISSN: 0003-0147; 1537-5323
• DOI: 10.1086/669675

Inbreeding depression varies considerably among populations, but only some aspects of this variation have been thoroughly studied. Because inbreeding depression requires genetic variation, factors that influence the amount of standing variation can affect the magnitude of inbreeding depression. Environmental heterogeneity has long been considered an important contributor to the maintenance of genetic variation, but its effects on inbreeding depression have been largely ignored by empiricists. Here we compare inbreeding depression, measured in two environments, for 20 experimental populations of Drosophila melanogaster that have been maintained under four different selection regimes, including two types of environmentally homogeneous selection and two types environmentally heterogeneous selection. In line with theory, we find considerably higher inbreeding depression in populations from heterogeneous selection regimes. We also use our data set to test whether inbreeding depression is correlated with either stress or the phenotypic coefficient of variation (CV), as suggested by some recent studies. Though both of these factors are significant predictors of inbreeding depression in our study, there is an effect of assay environment on inbreeding depression that cannot be explained by either stress or CV.