Affiliation:
1. Department of Aquatic Ecology, Eawag Swiss Federal Institute of Aquatic Science and Technology Zürich Switzerland
2. Division of Aquatic Ecology and Evolution Institute of Ecology and Evolution University of Bern Bern Switzerland
3. Department of Fish Ecology and Evolution Eawag, Swiss Federal Institute of Aquatic Science and Technology Center of Ecology Evolution and Biochemistry Lucerne Switzerland
4. Aquatic Ecology Group University of Vic Central University of Catalonia Vic Spain
Abstract
Abstract
Hybridization following secondary contact of genetically divergent populations can influence the range expansion of invasive species, though specific outcomes depend on the environmental dependence of hybrid fitness. Here, using two genetically and ecologically divergent threespine stickleback lineages that differ in their history of freshwater colonization, we estimate fitness variation of parental lineages and hybrids in semi-natural freshwater ponds with contrasting histories of nutrient loading. In our experiment, we found that fish from the older freshwater lineage (Lake Geneva) and hybrids outperformed fish from the younger freshwater lineage (Lake Constance) in terms of both growth and survival, regardless of the environmental context of our ponds. Across all ponds, hybrids exhibited the highest survival. Although wild-caught adult populations differed in their functional and defence morphology, it is unclear which of these traits underlie the fitness differences observed among juveniles in our experiment. Overall, our work suggests that when hybrid fitness is insensitive to environmental conditions, as observed here, introgression may promote population expansion into unoccupied habitats and accelerate invasion success.
Abstract
We experimentally tested the performance of two divergent stickleback lineages and their hybrids under contrasting environmental conditions in a common garden setting. Hybrid fitness appeared insensitive to environmental conditions, and this could indicate that naturally occurring introgression between the populations may promote population expansion.
Funder
Eidgenössische Anstalt für Wasserversorgung Abwasserreinigung und Gewässerschutz
European Regional Development Fund
SeeWandel: Life in Lake Constance - the past, present and future
Publisher
Oxford University Press (OUP)
Subject
Ecology, Evolution, Behavior and Systematics