Skip to main content
Dryad logo

Mating systems and predictors of relative reproductive success in a Cutthroat Trout subspecies of conservation concern

Citation

Hargrove, John et al. (2021), Mating systems and predictors of relative reproductive success in a Cutthroat Trout subspecies of conservation concern, Dryad, Dataset, https://doi.org/10.5061/dryad.zcrjdfncd

Abstract

Mating systems and patterns of reproductive success in fishes play an important role in ecology and evolution. While information on the reproductive ecology of many anadromous salmonids (Oncorhynchus spp.) is well-detailed, there is less information for non-anadromous species including the Yellowstone Cutthroat Trout (O. clarkii bouvieri), a subspecies of recreational angling importance and conservation concern. Using data from a parentage-based tagging study, we described the genetic mating system of a migratory population of Yellowstone Cutthroat Trout, tested for evidence of sexual selection, and identified predictors of mating and reproductive success. The standardized variance in mating success (i.e., opportunity for sexual selection) was significantly greater for males relative to females, and while the relationship between mating success and reproductive success (i.e., Bateman gradient) was significantly positive for both sexes, a greater proportion of reproductive success was explained by mating success for males (r2 = 0.80) than females (r2 = 0.59). Overall, the population displayed a polygynandrous mating system, whereby both sexes experienced variation in mating success due to multiple mating, and sexual selection was variable across sexes. Tests for evidence of sexual selection indicated the interaction between mating success and total length best predicted relative reproductive success. We failed to detect a signal of inbreeding avoidance among breeding adults, but the group of parents that produced progeny were on average slightly less related than adults that did not produce progeny. Lastly, we estimated the effective number of breeders (Nb) and effective population size (Ne) and identified while Nb was lower than Ne, both are sufficiently high to suggest Yellowstone Cutthroat Trout in Burns Creek represent a genetically stable and diverse population.

Methods

The genetic data set provided was generated via sampling of Yellowstone Cutthroat Trout at a weir on a spawning tributary (Burns Creek) of the South Fork Snake River, Idaho, USA. Each migrating adult was sampled for a genetic sample and the length and date of sampling was recorded for each individual. Juveniles emigrating from the same system later the same year were also sampled for genetics. In the lab, DNA was extracted and each individual was amplified at a panel of 134 single nucleotide polymorphisms (SNPs) using a Genotyping-in-Thousands (GT-seq) protocol.

Parentage analysis was performed using the algorithms implemented in SNPPIT, specifically juveniles were assigned to parent-pairs. We created reproductive profiles for each adult including the number of offspring assigned, number of mates. Analysis of genetic mating systems involved summarizing the means and variances of reproductive success (offspring assigned) and mating success (number of mates) for each sex. We compared phenotypic traits of fish that did and did not mate to test for evidence of sexual selection.

Usage Notes

Please see the attached README file for a detailed description of the data included in the dataset and how data were analyzed

Funding

Federal Aid in Sport Fish Restoration Act

Federal Aid in Sport Fish Restoration Act