Tropical Insects Approach Heat Tolerance Limits as Climate Change Accelerates

A study of more than 2,000 insect species across Kenya and Peru finds that many tropical insects are already operating close to their physiological heat tolerance limits, with lowland species most at risk as temperatures continue to rise. The findings warn that rapid loss of insect populations could destabilise pollination, food systems and broader ecosystem functioning in tropical regions.

Researchers studying over 2,000 insect species across field sites in Kenya and Peru found that a significant proportion of lowland tropical insects, particularly flies and other non-migratory species, are already experiencing temperatures close to their upper heat tolerance thresholds. Unlike species in temperate zones, which may benefit from or adapt more easily to warming, tropical insects have evolved in relatively stable thermal environments and have limited physiological flexibility to cope with novel high-temperature conditions.

Insects represent up to 90 per cent of all animal species and perform ecosystem services of critical global importance, including pollination of approximately 75 per cent of the world's food crops. In the tropics, which host the highest insect diversity on Earth, climate-driven population declines could cascade through food webs, reducing pollination services, decomposition rates and prey availability for insectivorous birds and mammals. India, which spans tropical and subtropical zones, would face agricultural and ecological consequences from significant insect loss.

The researchers recommend habitat protection and creation of climate corridors as the most immediately available tools to support insect species survival under warming conditions. Reducing land-use pressures such as pesticide use, deforestation and monoculture expansion would provide additional resilience. The study's authors warn that current international climate and biodiversity policy frameworks do not adequately address insect vulnerability, and call for dedicated monitoring programmes to track population trends in the most exposed tropical zones.

Key figure — 90% of all animal species are insects, the majority found in at-risk tropical regions