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Spatial environmental complexity mediates sexual conflict and sexual selection in Drosophila melanogaster

Citation

Long, Tristan; Malek, Heather (2019), Spatial environmental complexity mediates sexual conflict and sexual selection in Drosophila melanogaster, Dryad, Dataset, https://doi.org/10.5061/dryad.00000001t

Abstract

Sexual selection is an important agent of evolutionary change, but the strength and direction of selection often vary over space and time. One potential source of heterogeneity may lie in the opportunity for male–male and/or male–female interactions imposed by the spatial environment. It has been suggested that increased spatial complexity permits sexual selection to act in a complementary fashion with natural selection (hastening the loss of deleterious alleles and/or promoting the spread of beneficial alleles) via two (not mutually exclusive) pathways. In the first scenario, sexual selection potentially acts more strongly on males in complex environments, allowing males of greater genetic “quality” a greater chance of outcompeting rivals, with benefits manifested indirectly in offspring. In the second scenario, increased spatial complexity reduces opportunities for males to antagonistically harm females, allowing females (especially those of greater potential fecundities) to achieve greater reproductive success (direct fitness benefits). Here, using Drosophila melanogaster , we explore the importance of these mechanisms by measuring direct and indirect fitness of females housed in simple vial environments or in vials in which spatial complexity has been increased. We find strong evidence in favor of the female conflict‐mediated pathway as individuals in complex environments remated less frequently and produced more offspring than those housed in a simpler spatial environment, but no difference in the fitness of sons or daughters. We discuss these results in the context of other recent studies and what they mean for our understanding of how sexual selection operates.

Methods

There are three files associated with this data set.

Remating Offpsring.csv contains counts of the number of red-eyed and brown-eyed offspring produced individual female flies housed in vials that offered either a simple (control, C) or spatially complex (experiental, E) environment. The presence of red-eyes indicates remating.

sonsfitness.csv contains estimates of the reproductive success of male flies whose mother had been housed in either a simple (control, C) or spatially complex (experiental, E) environment for varying numbers of days. From a bundle of test-tubes, we counted the number of females (1 female per test-tube) that had mated with the target son (presence of red-eyed offpsring produced). The total number of offspring sired by the target male is also recorded.

agg_daughters.csv contains the mean number of offspring produced by females whose mother had been housed in either a simple (control, C) or spatially complex (experiental, E) environment for varying numbers of days.

Funding

Natural Sciences and Engineering Research Council of Canada