Tropical insects and other temperature-dependent critters that make their home in the tropics could be in grave danger from climate change, according to a new study published in the Proceedings of the National Academy of Sciences. As opposed to species at the world’s poles that frequently encounter a wide range of temperatures, tropical insects and other creatures live within a very narrow temperature range throughout the year, and even a change of a few degrees can mess with their physiology. “In the tropics many species appear to be living at or near their thermal optimum, a temperature that lets them thrive,” said Joshua Tewksbury of the University of Washington. “But once temperature gets above the thermal optimum, fitness levels most likely decline quickly and there may not be much they can do about it.” Researchers forecast trouble for such temperature-dependent species since significant harmful effects can be triggered by a rise of between 2 and 4 degrees Fahrenheit. Temperatures in the tropics are expected to rise by some 9 degrees Fahrenheit by 2100.