DOI: 10.5061/dryad.7d7wm3824
title: Data from: The effect of operational sex ratio and density on the strength of sexual selection against mutant males in Drosophila melanogaster

description: Higher male:female operational sex ratio (OSR) is often assumed to lead to
 stronger sexual selection on males. Yet, this premise has been directly
 tested by very few studies, with mixed outcomes. We investigated how OSR
 affects the strength of sexual selection against two deleterious alleles,
 a natural ebony mutant and a transgenic GFP insertion, in Drosophila
 melanogaster. To this end, we estimated the relative paternity share of
 homozygous mutant males competing against wildtype males under different
 OSRs (1:2, 1:1, 2:1). We also manipulated the mating pool density (18, 36
 or 54 individuals), and assessed paternity over three consecutive days,
 during which the nature of sexual interaction changed. The strength of
 sexual selection against the ebony mutant increased with OSR, became
 weaker after the first day and was little affected by density. In
 contrast, sexual selection against the GFP transgene was markedly affected
 by density: at the highest density it increased with OSR, but at lower
 densities it was strongest at 1:1 OSR, remaining strong throughout the
 experiment. Thus, while OSR can strongly affect the strength of sexual
 selection against “bad genes”, it does not necessarily increase
 monotonically with male:female OSR. Furthermore, the pattern of
 relationship between OSR and the strength of sexual selection can be
 locus-specific, likely reflecting the specific phenotypic effects of the
 mutation.
description: The experiments measured the relative sexual fitness of males
 carrying one of two mutant alleles (ebony or GFP) competing with wildtype
 males, depending on the operational sex ratio (OSR) and total number
 (density) of interacting individuals. Mating groups of virgin Drosophila
 individuals were set up at different operational sex ratios (1:2, 1:1,
 2:1) and at different total numbers of individuals (18, 36, 54). Mutant
 and wildtype males were always at 2:1 ratio to each other. The mating
 groups interacted over 3 days. The proportional paternity of the mutant
 males was obtianed for offspring produced on each day.
 An additional experiment was performed to compare the mating
 success of GFP and wildtype males. 12 GFP and 6 wildtype males were set up
 together with 18 wildtype females and the number of mating was observed
 over 8 hours. For details, see the paper.
description: # Data from: The effect of operational sex ratio and density on the
 strength of sexual selection against mutant males in Drosophila
 melanogaster The
 experiments measured the relative sexual fitness of males carrying one of
 two mutant alleles (ebony or GFP) competing with wildtype males, depending
 on the operational sex ratio (OSR) and total number (density) of
 interacting individuals. Mating groups of virgin Drosophila individuals
 were set up at different operational sex ratios (1:2, 1:1, 2:1) and at
 different total numbers of individuals (18, 36, 54). Mutant and wildtype
 males were always at 2:1 ratio to each other. The mating groups interacted
 over 3 days. The proportional paternity of the mutant males was obtianed
 for offspring produced on each day. An additional experiment was performed
 to compare the mating success of GFP and wildtype males. 12 GFP and 6
 wildtype males were set up together with 18 wildtype females and the
 number of mating was observed over 8 hours. For details, see the paper. ##
 Description of the data and file structure Sheets 1 and 2 contain the data
 (the number of mutant and wildtype offspring) from the competitive
 paternity experiments with ebony and GFP males, respectively Columns:
 Batch: each experiment was performed in four batches ReplID: unique ID of
 each replicate cage OSR: the operational sex ration males/females Density:
 the total number of individuals put in the cage Males, Females: the number
 of individuals of each sex put in the cage (note that 2/3 of males were
 mutant and 1/3 were wildtype) ebony: the number of ebony offspring (in
 sheet 1) GFP: the number of GFP offspring (in sheet 2) wildtype: the
 number of wildtype offspring Sheet 3 contains the data (the number of
 matings by each male genotype observed at each timepoint) form the
 competitive mating experiment with GFP and wildtype males. ReplID: unique
 replicate ID Time: from the onset of the experiment in hours Genotype:
 male type (GFP or wildtype; 12 GFP and 6 wildtype males were placed in
 each cage together with 18 virgin females) Color: the color of the powder
 used for the focal male genotype in the particular replicate MatingCount:
 the number of matings by males of a given genotype observed at a
 particular time point NA: data not available (for various reasons, mostly
 because some flies died)