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Data and script for: Weapons evolve faster than sperm in bovids and cervids

Citation

Fitzpatrick, John (2021), Data and script for: Weapons evolve faster than sperm in bovids and cervids, Dryad, Dataset, https://doi.org/10.5061/dryad.dbrv15f19

Abstract

In polyandrous species, males face reproductive competition both before and after mating. Sexual selection thus shapes the evolution of both pre- and postcopulatory traits, creating competing demands on resource allocation to different reproductive episodes. Traits subject to strong selection exhibit accelerated rates of phenotypic divergence, and examining evolutionary rates may inform us about the relative importance and potential fitness consequences of investing in traits under either pre- or postcopulatory sexual selection. Here, we used a comparative approach to assess evolutionary rates of key competitive traits in two artiodactyl families, bovids (family Bovidae) and cervids (family Cervidae), where male-male competition can occur before and after mating. We quantified and compared evolutionary rates of male weaponry, body size/mass, testes mass, and sperm morphometrics. We found that weapons evolve faster than sperm dimensions. In contrast, testes and body mass evolve at similar rates. These results suggest strong, but differential, selection on both pre- and postcopulatory traits in bovids and cervids. Furthermore, we documented distinct evolutionary rates among different sperm components, with sperm head and midpiece evolving faster than the flagellum. Finally, we demonstrate that, despite considerable differences in weapon development between bovids and cervids, the overall evolutionary patterns between these families were broadly consistent.

Methods

Length and mass data for a range of sexual and somatic traits of ungulates were compiled from the literature. Male sexual weapon length (n = 135; i.e. antlers in cervids and horns in bovids), sperm head, midpiece and total flagellum length (all n = 53), and male muzzle width (n = 88) were represented by linear measurements. Traits measured using mass values included combined testes mass (n = 71) and male body mass (n = 135).

Usage Notes

Analytical scripts are run in R.

Funding

Knut och Alice Wallenbergs Stiftelse, Award: 2016-0146

Vetenskapsrådet, Award: 2017-04680

Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Award: PP00P3-170669