Heat tolerance variation reveals vulnerability of tropical herbivore-parasitoid interactions to climate change

Assessing the heat tolerance (CTmax) of organisms is central to understand the impact of climate change on biodiversity. While both environment and evolutionary history affect CTmax, it remains unclear how these factors and their interplay influence ecological interactions, communities and ecosystems under climate change. We collected and reared caterpillars and parasitoids from canopy and ground layers in different seasons in a tropical rainforest. We tested the CTmax and Thermal Safety Margins (TSM) of these food webs with implications for how species interactions could shift under climate change. We identified strong influence of phylogeny in herbivore-parasitoid community heat tolerance. The TSM of all insects were narrower in the canopy and parasitoids had lower heat tolerance compared to their hosts. Our CTmax-based simulation showed higher herbivore-parasitoid food web instability under climate change than previously assumed, highlighting the vulnerability of parasitoids and related herbivore control in tropical rainforests, particularly in the forest canopy.

Automated summary

Assessing the heat tolerance (CTmax) of organisms is crucial for understanding the impact of climate change on biodiversity. This study investigated how environment, evolutionary history, and their interactions influence species interactions in tropical rainforests under climate change. Findings showed that phylogeny played a significant role in determining heat tolerance in herbivore-parasitoid communities. The study also highlighted the vulnerability of parasitoids and herbivore control in tropical rainforests, particularly in the canopy.