Species-specific reduction of survival and predation in ladybirds exposed to prolonged and intensified heat waves.

Climate change exacerbates heat waves, threatening ecosystems by disrupting species survival and interactions. Insects are highly sensitive to temperature extremes, exhibiting species-specific stress which can impact community dynamics. Ecosystem services, such as pest control, can therefore be reduced by heat stress. We studied how five ladybird species responded to heat wave conditions, focusing on survival and aphid consumption. While survival was generally unaffected by exposure to realistic heat waves (compared to normal summer temperatures), extreme heat wave (+5°C) reduced survival in four out of five species. Interestingly, one of the most vulnerable species to extreme heat waves was the globally invasive Harmonia axyridis, reaching over 50% mortality in less than 2 days. Prolonged exposure to heat waves (over 6 days) escalated mortality in two species and significantly decreased aphid consumption in another two species. This study underscores the potential impacts of heat waves on pest control in a warming world.