Simulated heatwave conditions associated with global warming affect development and competition between hyperparasitoids

Anthropogenic global warming and attendant effects like heatwaves affect the biology and ecology of both individuals and species within and across different trophic levels. Here, we examined the effects of a simulated heatwave on development of and competition between two hyperparasitoid wasps, Lysibia nana and Acrolyta nens when attacking the same host, cocoons of the primary parasitoid, Cotesia glomerata. Parasitized hosts were exposed to three different day and night temperature regimes (low, medium and high) that reflect cool, normal and heatwave conditions in the Netherlands. We found that higher temperatures decreased survival to eclosion more strongly in the hyperparasitoids than in their host. Heatwave conditions also shortened development time and led to the production of smaller adult wasps of both hyperparasitoid species in singly parasitized hosts. In multiparasitized hosts, L. nana won most of the contests when it oviposited first, irrespective of the time interval between ...