Forget about the plight of the polar bears for awhile, according to some scientists tropical insects will be the first victims of extinction caused by warming temperatures. Apparently more attention has been devoted to colder regions and their wildlife because temperature changes there are predicted to be far more dramatic than tropical areas. However even a shift of one to two degrees the the warmer regions could prove detrimental to the survival of the insects living there, who researchers say are already living at their limit of their temperature change.

"Many tropical species can only tolerate a narrow range of temperatures because the climate they experience is pretty constant throughout the year," said Curtis Deutsch, assistant professor of atmospheric and oceanic sciences at the University of California, Los Angeles, who co-authored the study published in the journal Proceedings of the National Academy of Sciences. "Our calculations show that they will be harmed by rising temperatures more than would species in cold climates. Unfortunately, the tropics also hold the large majority of species on the planet."

Insects are especially important to their tropical environment because they break down organic matter and pollinate local plants that yield fruits and nuts that other animals higher in the food chain rely on for survival. Unfortunately the study has determined their ability to adapt to even minor changes is limited.

"There's a strong relationship between your physiology and the climate you live in. 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 Washington University, another of the study's co-authors. "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."

"The direct effects of climate change on the organisms we studied appear to depend a lot more on the organisms' flexibility than on the amount of warming predicted for where they live," said Dr Tewksbury. "The tropical species in our data were mostly thermal specialists, meaning that their current climate is nearly ideal and any temperature increases will spell trouble for them."

» The Independent