Reproducing in hot water: experimental heatwaves deteriorate multiple reproductive traits in a freshwater ectotherm

Heatwaves are occurring at an increasing frequency and intensity under ongoing climate change. With many reproductive traits – including mating behaviour and gamete traits– being sensitive even to small stressors, including short temperature changes, the impact of heatwaves on reproduction and sexual selection processes is likely to be vast. Also, understanding whether the sexes may differentially respond to these extreme events is crucial to understand the impact on fecundity and the consequence at the population level. Nonetheless, our knowledge of the effects of heatwaves on these key aspects of an animal life is still limited. Here, we expose recently mated male and female guppies (Poecilia reticulata) to an experimental heatwave (32°C, 6°C above the control, for 5 days) to determine its effects on several traits, including sexual behaviour, condition, ornamentation, and fertility. Using this design, in contrast to most other experimental set ups, we had the possibility to attribute..., ,