Data from: Mixed evidence for intralocus sexual conflict from male-limited selection in Drosophila melanogaster
Data files
Oct 16, 2025 version files 96.94 KB
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F_CRF_wt.cr.csv
12.69 KB
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F_HClines.csv
14.38 KB
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M_CRF_wt.cr.csv
26.10 KB
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M_HClines.csv
5.40 KB
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M_MC_wt.cr.csv
16.88 KB
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M_SC_wt.cr.csv
15.11 KB
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README.md
6.37 KB
Abstract
Sexual conflict over shared traits – intralocus sexual conflict (IaSC) – may be common and consequential, but experimental tests of its relative magnitude are challenging and limited in number. We use a sex-limited selection experiment, designed to subject haplotypes of Drosophila melanogaster to selection for male fitness without opposing selection acting on female fitness. Importantly, we use three novel base populations to compare results with those from the LHM population, the sole population investigated using this technique. In contrast with previous studies, we find that the male fitness of haplotypes subject to male-limited selection (ML populations) is not consistently better than their matched (MC) controls when tested in the “wildtype” state. Males from ML lines did not outperform controls in competitive fitness assays, mate choice trials, fecundity induction, or sperm offense tests. As predicted, genetic variation for male fitness was reduced, with low fitness haplotypes apparently removed by selection, but this was only surveyed in one replicate population pair and included a potential artifact in the protocol. Female fitness was markedly reduced by carriage of ML haplotypes, as predicted by sexual antagonism. Hence, our results are only partially consistent with the IaSC hypothesis, raising questions about the relative contribution of sexual conflict to the standing genetic variation in these populations and the potential role of artifacts in the protocol that may have obscured our ability to detect IaSC.
Title of Dataset
Wild-type estimates of fitness, sperm comp, mate choice, and heritable variation for fitness under male-limited experimental evolution.
Associated Publication
- Title: Mixed evidence for intralocus sexual conflict from male-limited selection in Drosophila melanogaster
- Journal: Journal of Heredity
- Authors:
- Harshavardhan Thyagarajan,
- Imran Sayyed,
- Mindy G. Baroody,
- Joshua A. Kowal,
- Troy Day,
- Adam K. Chippindale
Dataset Overview
This dataset contains experimental data on fitness, mate choice and sperm competition measurements for male-limited and control selection populations; and fitness measurements for hemiclones expressed male and female backgrounds. The data pertains to experimentally evolved Drosophila melanogaster populations. The data are provided as CSV files.
The six files correspond to different experimental assays:
M_CRF_wt.cr.csv— Male competitive reproductive fitness assayF_CRF_wt.cr.csv— Female competitive reproductive fitness assayM_SC_wt.cr.csv— Male sperm competition assay dataM_MC_wt.cr.csv— Male mating competition (mating latency and duration)M_HClines.csv— Hemiclonal male competitive reproductive fitness assayF_HClines.csv— Hemiclonal female fecundity assay
Common variables:
- Selection
ML — Male limited
MC — Matched control (matched by replicate number, for example ML1 and MC1) - Treatment — In experiments where the ML haplotypes were expressed in a variety of treatments, these are labelled as follows. If a treatment variable is not provided, it means that all the animals under selection "ML" were studied under conditions resembling MLSD. Where
Treatmentis provided, the variableSelectionis normally excluded asTreatmentcovers this information.
MLSD — ML, single dose of entire haplotype
MLSDa — ML, single dose of autosomes
MLDD — ML, double dose
MC — MC (analogous to MLDD) - Replicate — This describes the replicate pairs of selected and control populations. It is necessary to clarify here the method of setting up replicates. Commonly, a single source population is used to derive n statistical replicate populations under selection / control conditions. Here rather, we use 3 long separated populations (themselves originally derived as statistical replicates over 20 years prior) to initiate each selection / control pair.
- Contest — An identifier for a distinct chamber in which an assay was conducted. In fitness assays, in each contest, we had 30 target animals compete 30 recessively marked competitors of the same sex for the maximum reproductive output, in the presence of 50 animals of the opposite sex.
File Details
1. M_CRF_wt.cr.csv
- Dimensions: 851 rows × 7 columns
2. F_CRF_wt.cr.csv
- Dimensions: 423 rows × 7 columns
- Columns: (for both 1 & 2)
Gen— Generation number, categoricalTreatment— Described above, categoricalReplicate— Described above, categoricalContest— Described above, categoricalVial— Vial number, statistical replicate unit of competitive outcome from a single contest, categoricalRed— Number of red-eyed progeny, countBrown— Number of brown-eyed progeny, count
3. M_SC_wt.cr.csv
- Dimensions: 619 rows × 6 columns
- Columns:
Treatment— Described above, categoricalReplicate— Described above, categoricalBundle— Analogous to contest - a bundle represents flies that were housed together during testing, categoricalVial— Each vial represents data from a single female laying eggs. Nested within bundle as with vials within contest in CRF assays, categoricalU— Number of mutant (recessively marked) offspring, countWT— Number of wild-type progeny, count
4. M_MC_wt.cr.csv
- Dimensions: 273 rows × 14 columns
- NAs: NA here refers to cells where the data is not available.
- Columns:
Selection— Described above, categoricalReplicate— Described above, categoricalVial.ID— Identifier of independent contest between animals in this experiment, not nested here, categoricalObs.start.time— Observed start time of assay, hh:mmMating.start.time— Time when mating began, hh:mmMating.end.time— Time when mating ended, hh:mmMated.male— Identity of mating male (wt - aka target / bw - recessive competitor), categoricalMales— Number of males present in vial, countFemales— Number of females present in vial, countObs.start.time.Corr— Converted observation start time (minutes since ref), numericMating.start.time.Corr— Converted mating start time, numericMating.end.time.Corr— Converted mating end time, numericLatency— Time from observation to mating start, minutesDuration— Duration of mating, minutes
5. M_HClines.csv
- Dimensions: 367 rows × 5 columns
- Columns:
Selection— Described above, categoricalLine— Hemiclone line number, categoricalVial— Vial number - analogous to contest here (no nesting within another variable), categoricalRed.offspring— Number of red-eyed progeny, countPeach.offspring— Number of brown-eyed progeny, count
6. F_HClines.csv
- Dimensions: 367 rows × 5 columns
- Columns:
Selection— Described above, categoricalLine— Hemiclone line number, categoricalVial— Vial number - analogous to contest here (no nesting within another variable), categoricalPupal.count— Number of offspring of target females, counted at the pupal stage, countDams.Count— Number of females that were introduced into egg-laying vials (typically designed to be 4, but sometimes fewer), count
License
This dataset is released under the CC0 1.0 Universal license in accordance with Dryad’s policies.
Citation
Thyagarajan, H. et al. (2025). Dataset: Mixed evidence for intralocus sexual conflict from male-limited selection in Drosophila melanogaster. Dryad Digital Repository. DOI: 10.5061/dryad.ncjsxkt8p
Full methodological details are provided in the associated publication. Breeding designs used to produce animals from various treatments can be found in the online supplement.
- Competitive reproductive fitness (CRF) was assayed for both males and females against competitive recessive (Cr) marker stocks in equal numbers. Test females were collected as virgins and test males at 10–11 days post-oviposition. On day 12, groups of 30 MC or ML flies were combined with 30 Cr of the same sex and 50 Cr of the opposite sex in ventilated “mini-cages” with yeast for 2 days. Six competition arenas (“contests”) were set up per population, and offspring proportions from six egg vials per arena were counted to estimate CRF.
- Fitness assays for hemiclonal analysis followed a similar design with reduced competition size to accommodate 76 lines. For males, 4 test flies were combined with 4 Cr males and 6 Cr females. For females, 4 virgins were combined with 3 Cr males, and productivity (pupal count) was used as a proxy for fitness. Up to 5 contests were run per line, and complete hemiclonal data were obtained for 76 of 80 lines.
- Male mating success: Single test males were combined with a Cr male and a Cr virgin female. When one pair initiated copulation, the rival male was removed without disturbance, and the mating event was monitored until separation. Mating latency, mating duration, and the offspring produced (sex ratio, fecundity induction, and eye-color marker) were recorded to identify the successful sire. Fifty binary choice vials were set up per treatment within each replicate line.
- Sperm competition (P2): Groups of 12 virgin Cr females were combined with Cr males, and matings were closely observed. After mating, Cr males were removed. On day 13, 10 “target” males (MC or ML) were added to each vial for a second mating, observed for ~3 hours to prevent multiple matings. Ten females per vial were then isolated for 24 hours to lay eggs. Offspring were scored by eye color to determine the proportion sired by the second male. Each treatment included 30 replicate vials.