A sweeping new study of more than 2,000 insect species reveals a troubling reality: many insects may be far less capable of coping with rising temperatures than scientists once hoped. Researchers found that while some species living at higher altitudes can temporarily boost their heat tolerance, many insects in tropical lowlands—where biodiversity is highest—lack this flexibility. Because insects play essential roles as pollinators, decomposers, and predators, their vulnerability could ripple through entire ecosystems.