Data from: On the expression of male harm in Drosophila melanogaster: impacts of density and structural complexity of the mating environment
Data files
Nov 19, 2025 version files 42.64 KB
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complexity_exp_DRYAD_data.csv
8.86 KB
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density_exp_DRYAD_data.csv
13.75 KB
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R_code_DRYAD.R
16.30 KB
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README.md
3.73 KB
Abstract
Male harm occurs when traits in males that increase their reproductive success incidentally reduce female fitness. In Drosophila melanogaster, many lab studies have revealed the presence of male harm, but recent work has shown that its expression can be dramatically reduced, even eliminated, when sexual interactions and mating occur in an environment that differs from traditional lab rearing vials. Here we follow up on this to separately test the effect of fly density and structural complexity of the mating environment in mediating the expression of male harm. We performed separate two-way factorial assays that measured the fitness of females while manipulating their exposure to males and the density of flies or the structural complexity of the environment during exposure. Male harm, quantified as the relative reduction in female fitness under increased male exposure, was not affected by density, but was significantly reduced –essentially eliminated– by increased structural complexity. Our results demonstrate that seemingly simple choices, like the environment used in a laboratory model system, can have profound impacts on the expression of harm and hence views on the prevalence of sexual conflict. This is noteworthy because conflict can shape other fundamental evolutionary processes including adaptation, purging, and speciation.
Dataset DOI: 10.5061/dryad.573n5tbnt
Description of the data and file structure
Data and code for “On the expression of male harm in Drosophila melanogaster: impacts of density and structural complexity of the mating environment”, published by Osijo, Agrawal & Rundle in Evolution.
Two experiments were performed, one manipulating the density of the mating environment and one manipulating the structural complexity of the mating environment. Data are provided for each as separate files, along with R code for analyzing both. Details of the methods are in published paper.
Files and variables
File: density_exp_DRYAD_data.csv (called 'my_data1' in R code)
Description: Data from the experiment that tested the effect of fly density on male-induced harm to females. The fitness of females was quantified in a two-way factorial experiment that manipulated their exposure to males (intermittent vs. continuous) and the number of flies (low vs. high density) during a four-day interaction period. NA values in row 77 denote missing data due to a technical error during the experiment.
Variables
- Block: experimental block
- Env: the density of flies in the mating environment: lowD = low density, highD = high density
- ExpLevel: male exposure treatment: Low = intermittent exposure to males, High = continuous exposure to males
- Container_ID: unique ID for each replicate container
- Fem_surviving: number of females that survived the 4-day interaction period (out of 15 for lowD, 60 for highD)
- Fem_dying: number of females that died during the 4-day interaction period
- total_offspring: total number of offspring produced by surviving females
- offspring_per_surviving_female: total number of offspring divided by the number of surviving females
- female_survival: number of females surviving divided by the total number of females (i.e. the sum of the number of females surviving and the number of females dying)
- AvgNumOff: female fitness, estimated as offspring_per_surviving_female * female_survival
File: R_code_DRYAD.R
Description: R code for analyzing both data sets
File: complexity_exp_DRYAD_data.csv (called 'my_data2' in R code)
Description: Data from the experiment that tested the effect of the structural complexity of the mating environment on male-induced harm to females. The fitness of females was quantified in a two-way factorial experiment that manipulated their exposure to males (intermittent vs. continuous) and the structural complexity of the mating environment (simple vs. complex) during a four-day interaction period.
Variables
- Block: experimental block
- Env: the complexity of the mating environment: sim = simple, com = complex
- ExpLevel: male exposure treatment: Low = intermittent exposure to males, High = continuous exposure to males
- Container_ID: unique ID for each replicate container
- Fem_surviving: number of females that survived the 4-day interaction period (out of 15)
- Fem_dying: number of females that died during the 4-day interaction period
- total_offspring: total number of offspring produced by surviving females
- offspring_per_surviving_female: total number of offspring divided by the number of surviving females
- female_survival: number of females surviving divided by the total number of females (i.e.,15)
- AvgNumOff: female fitness, estimated as offspring_per_surviving_female * female_survival
Code/software
R (v4.4.2) code for analyzing data. Packages: car
Code is annotated.