Abstract
Human-mediated hybridization threatens many native species, but the effects of introgressive hybridization on life-history expression are rarely quantified, especially in vertebrates. We quantified the effects of non-native rainbow trout admixture on important life-history traits including growth and partial migration behavior in three populations of westslope cutthroat trout over five years. Rainbow trout admixture was associated with increased summer growth rates in all populations and decreased spring growth rates in two populations with cooler spring temperatures. These results indicate that non-native admixture may increase growth under warmer conditions, but cutthroat trout have higher growth rates during cooler periods. Non-native admixture consistently increased expression of migratory behavior, suggesting that there is a genomic basis for life-history differences between these species. Our results show that effects of interspecific hybridization on fitness traits can be the product of genotype-by-environment interactions even when there are minor differences in environmental optima between hybridizing species. These results also indicate that while environmentally mediated traits like growth may play a role in population-level consequences of admixture, strong genetic influences on migratory life-history differences between these species likely explains the continued spread of non-native hybridization at the landscape-level, despite selection against hybrids at the population-level.
| Original language | English |
|---|---|
| Pages (from-to) | 821-833 |
| Number of pages | 13 |
| Journal | Evolutionary Applications |
| Volume | 14 |
| Issue number | 3 |
| DOIs | |
| State | Published - Mar 2021 |
Funding
Funding for this project was provided by NSF grant DEB‐1258203, the USGS Northern Rocky Mountain Science Center, and Bonneville Power Administration grant no. 199101903 to MTFWP. Its contents are solely the responsibility of the authors and do not necessarily represent the views of the NW CASC or the USGS. JS was funded by the UM Wildlife Biology Program, MTFWP, the Montana Institute on Ecosystems, Westslope Chapter Trout Unlimited Scholarship, Steven P. Cramer Legacy Scholarship, Les Pengelly Scholarship, and through a Department of the Interior Northwest Climate Adaptation Science Center graduate fellowship. Funding for this project was provided by NSF grant DEB-1258203, the USGS Northern Rocky Mountain Science Center, and Bonneville Power Administration grant no. 199101903 to MTFWP. Its contents are solely the responsibility of the authors and do not necessarily represent the views of the NW CASC or the USGS. JS was funded by the UM Wildlife Biology Program, MTFWP, the Montana Institute on Ecosystems, Westslope Chapter Trout Unlimited Scholarship, Steven P. Cramer Legacy Scholarship, Les Pengelly Scholarship, and through a Department of the Interior Northwest Climate Adaptation Science Center graduate fellowship. The authors thank B. Triano, A. Steed, V. D'Angelo, A. Lamont, G. Bobo, W. Dokai, W. Jacques, S. Harrison, N. Fisch, I. Anderson, R. Walker, L. Gu, and all other technicians with the University of Montana (UM), U.S. Geological Survey (USGS), and Montana Department of Fish, Wildlife, and Parks (MTFWP) for their contributions to data collection and sample processing. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
| Funder number |
|---|
| DEB‐1258203 |
| 199101903 |
Keywords
- fitness
- growth
- hybridization
- introgression
- invasive species
- migratory life history