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Male genital lobe morphology affects the chance to copulate in Drosophila pachea

Citation

Lefèvre, Bénédicte M.; Catté, Diane; Courtier-Orgogozo, Virginie; Lang, Michael (2022), Male genital lobe morphology affects the chance to copulate in Drosophila pachea, Dryad, Dataset, https://doi.org/10.5061/dryad.gj495j2

Abstract

Abstract Introduction Male genitalia are thought to ensure transfer of sperm through direct physical contact with female during copulation. However, little attention has been given to their pre-copulatory role with respect to sexual selection and sexual conflict. Males of the fruitfly Drosophila pachea have a pair of asymmetric external genital lobes, which are primary sexual structures and stabilize the copulatory complex of female and male genitalia. We wondered if genital lobes in D. pachea may have a role before or at the onset of copulation, before genitalia contacts are made. Results We tested this hypothesis with a D. pachea stock where males have variable lobe lengths. In 92 mate competition trials with a single female and two males, females preferentially engaged into a first copulation with males that had a longer left lobe and that displayed increased courtship vigor. In 53 additional trials with both males having partially amputated left lobes of different lengths, we observed a weaker and non-significant effect of left lobe length on copulation success. Courtship durations significantly increased with female age and when two males courted the female simultaneously, compared to trials with only one courting male. In addition, lobe length did not affect sperm transfer once copulation was established. Conclusion Left lobe length affects the chance of a male to engage into copulation. The morphology of this primary sexual trait may affect reproductive success by mediating courtship signals or by facilitating the establishment of genital contacts at the onset of copulation.

Usage Notes

Genitalia preparations D. pachea, stocks
Images for genital lobe length measurements D. pachea lab-stocks 15090-1698.01, 15090-1698.02, and selection stock. md5sum: f75b342d0bb56d1c3b31cfbc355c64c5 supplementary-data_1_epandrium-preparations_stocks.tar.gz

Female spermathecae, mate-competition experiment
Images for male genital lobe length measurements (D. pachea selection stock). md5sum: c82caf1bdf51900b41e3dbd5fb17fe7a  supplementary-data_2_spermathecae-preparations_mate-competition.tar.gz

Male genitalia, mate-competition experiment
Images for male genital lobe length measurements (D. pachea selection stock). md5sum: 04691905ff8e611eaade77c2cf8eba9e  supplementary-data_2_epandrium-preparations_mate-competition.tar.gz

Left anterior legs, mate-competition experiment
Images for male genital lobe length measurements (D. pachea selection stock). md5sum: 29fb466684df4b5df816d36285bc9c0c  supplementary-data_2_leg-preparations_mate-competition.tar.gz

Movies, mate-competition experiment, females 1698.01
Movies for mating behavior analysis of D. pachea females of stock 15090-1698.01 and two males of the selection stock. md5sum: 43e5215b5add2004d154c22afb35826f  supplementary-data_3_movies_1698-01_sel-lobe-length.tar.gz

Movies, mate-competition experiment, females 1698.02
Movies for mating behavior analysis of D. pachea females of stock 15090-1698.02 and two males of the selection stock. md5sum: 9da8fc9689256f9803ccacace1c0f3e0  supplementary-data_3_movies_1698-02_sel-lobe-length.tar.gz

Movies, mate-competition experiment, females 1698.01, lobe surgery
Movies for mating behavior analysis of D. pachea females of stock 15090-1698.01 and two males of the selection stock with surgically modified lobes. md5sum: 5f69e30f4e487ef17242d9f7bca6be5a  supplementary-data_3_movies_1698-01_modif-lobe-length.tar.gz

PacData, dataset for mate-competition analysis using the R-package TerryBradley2

Funding

European Research Council, Award: 337579