Hybridisation primes population invasiveness under environmental change

Research Highlight: Jermacz, Ł., Podwysocki, K., Desiderato, A., Bącela-Spychalska, K., Rewicz, T., Szczerkowska, E., Augustyniak, M., Gjoni, V., & Kobak, J. (2025). The same species, not the same invader: Metabolic responses of genetically distinct invasive populations of Dikerogammarus villosus (Sowinsky, 1894) and their intraspecific hybrid to environmental stresses. Journal of Animal Ecology, in press. Biological invasions are a major global environmental change that has contributed to most anthropogenic extinction events while costing trillions. Invasiveness and impact assessments are often done at the species level; however, there is growing recognition that intraspecific population-level differences can be profound, especially in response to environmental gradients. Jermacz et al. (2025) employ a series of experiments to compare physiological responses between two populations of a high-impact invasive amphipod, the ‘killer shrimp’ Dikerogammarus villosus, under stresses associated with climate change. Moreover, they assess the performance of intraspecific hybrids between the populations, which are expected to converge in future along their separate invasion routes from the Ponto-Caspian region. The main finding in their study is that—alongside differences in physiological performance between the two populations—their intraspecific hybrids exhibit significant performance advantages under environmental stress. The increased genetic diversity and phenotypic capacity afforded through hybridisation between distinct invasive populations could be a mechanism that bolsters invasion success under climate change. These findings have implications for fundamentally understanding and practically managing invasive populations in changing environments.