Periodic Reporting for period 1 - HeatWaveSS (Intra and inter-generational effects of heatwaves on sexually selected traits and reproductive success)
Reporting period: 2021-12-01 to 2023-11-30
Evidence that gradual climate change threatens biodiversity is growing. For instance, by forcing animals or plants to move to higher elevations or latitudes, global warming increases the risk of species extinction. However, the impact of climate change-driven extreme weather events, such as heatwaves, remains poorly understood. Heatwaves, unpredictable and unusually hot, may not only reduce survival chances but can also impact animals through sublethal effects on biological traits. For example, heatwaves may impair fertility and reproduction, as these traits are sensitive even to small temperature changes.
With support from the MSCA-program, the HeatWaveSS project set out to investigate the impacts of heatwaves on reproductive and behavioural traits, using Poecilia reticulata as a model species. In several carefully designed laboratory experiments, guppies were exposed to a 5-day experimental heatwave and the consequences on multiple traits quantified.
Sex-specific adverse effects of heatwaves on reproduction, behaviour, and survival were found. In pregnant females, heatwaves were detrimental, leading to a greatly reduced survival and offspring production. In males, they decreased the quality of colour ornaments (which they use to attract mates), altered sperm quality and sexual behaviour, and reduced spatial learning capacity. In both adults and juveniles, heatwaves seem to reduce reactions to predatory cues. These results point to potential ramifications of heatwaves on fitness and survival in the wild.
Some results from the project were already published in Functional Ecology (https://doi.org/10.1111/1365-2435.14279) and additional scientific publications about the research are now in progress. Project outcomes have also been disseminated at international scientific conferences, including the “International Society for Behavioral Ecology Congress” (2022, Sweden) and the recent “Winter Meeting of the Society for the Study of Animal Behaviour” (2023, U.K.) and through public engagement (2022, “La festa della Scienza a Padova”, Italy).
Sex-specific adverse effects of heatwaves on reproduction, behaviour, and survival were found. In pregnant females, heatwaves were detrimental, leading to a greatly reduced survival and offspring production. In males, they decreased the quality of colour ornaments (which they use to attract mates), altered sperm quality and sexual behaviour, and reduced spatial learning capacity. In both adults and juveniles, heatwaves seem to reduce reactions to predatory cues. These results point to potential ramifications of heatwaves on fitness and survival in the wild.
Some results from the project were already published in Functional Ecology (https://doi.org/10.1111/1365-2435.14279) and additional scientific publications about the research are now in progress. Project outcomes have also been disseminated at international scientific conferences, including the “International Society for Behavioral Ecology Congress” (2022, Sweden) and the recent “Winter Meeting of the Society for the Study of Animal Behaviour” (2023, U.K.) and through public engagement (2022, “La festa della Scienza a Padova”, Italy).
In conclusion, heatwaves can compromise not only survival, but also behaviour, fertility and reproductive success of a species, key elements for populations to persist. These findings highlight the importance of considering heatwaves when predicting the consequences of climate change on organisms, and ultimately biodiversity, now and in the future. This contributes to the European community no only by enhancing scientific knowledge, but also through potential applications in conservation actions.