Pollution offsets the rapid evolution of increased heat tolerance in a natural population

• Published in: The Science of the total environment 2024-09, Vol.944, p.173070, Article 173070
• Main Authors: Dong, Ying, Van de Maele, Marlies, De Meester, Luc, Verheyen, Julie, Stoks, Robby
• Format: Article
• Language: English
• Subjects: Cost of tolerance concept; Evolutionary rescue; Heat tolerance; Metal tolerance; Multiple stressors; Rapid thermal evolution
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2024.173070

Despite the increasing evidence for rapid thermal evolution in natural populations, evolutionary rescue under global warming may be constrained by the presence of other stressors. Highly relevant in our polluted planet, is the largely ignored evolutionary trade-off between heat tolerance and tolerance to pollutants. By using two subpopulations (separated 40 years in time) from a resurrected natural population of the water flea Daphnia magna that experienced a threefold increase in heat wave frequency during this period, we tested whether rapid evolution of heat tolerance resulted in reduced tolerance to the widespread metal zinc and whether this would affect heat tolerance upon exposure to the pollutant. Our results revealed rapid evolution of increased heat tolerance in the recent subpopulation. Notably, the sensitivity to the metal tended to be stronger (reduction in net energy budget) or was only present (reductions in heat tolerance and in sugar content) in the recent subpopulation. As a result, the rapidly evolved higher heat tolerance of the recent subpopulation was fully offset when exposed to zinc. Our results highlight that the many reports of evolutionary rescue to global change stressors may give a too optimistic view as our warming planet is polluted by metals and other pollutants. [Display omitted] •Evolution of tolerance to warming may increase vulnerability to pollutants.•Study at interface of anthroposhere, biosphere and hydrosphere•Old and recent Daphnia subpopulations were resurrected and exposed to zinc.•The higher heat tolerance of the recent Daphnia was offset when exposed to zinc.•Evolutionary rescue under global warming can be offset by pollutants.