UW study: Global warming could bring bountiful bugs

While fish may be floundering, a new study from the University of Washington suggests bugs could boom because of global warming.

Not only will many insect species be able to adapt to a hotter world, those that do will actually reproduce faster, biologist Ray Huey said.

"Warmer is better for insects," he said. "Species that are adapted to warm temperatures will have higher rates of population growth than species adapted to cooler temperatures."

That could mean population explosions of both bad and beneficial bugs.

"It would have consequences for agriculture and human health, since a lot of disease vectors are insects," said doctoral student Melanie Frazier, lead author of the study.

Bugs adapted to a warmer world are also likely to develop faster and be more voracious eaters than cold-weather species, Frazier said.

That jibes well with studies that have found disease-causing microbes and parasites carried by insects are more virulent and reproduce and mature more rapidly at warm temperatures, said Dr. Paul Epstein, associate director of the Center for Health and the Global Environment at Harvard Medical School.

Epstein, who was not involved in the UW study, has documented the spread of malaria and Dengue fever to mountainous regions of Africa, Asia and Latin America, coinciding with melting glaciers and shifting plant communities. "Malaria is circulating in Nairobi, which is a mile-high city," and had previously been free of the disease, he said.

Many biologists say climate change is partly to blame for insect infestations in forests from Arizona to Alaska, leaving the stands more vulnerable to fire. Huey's studies of fruit flies in North and South America and Europe have demonstrated genetic changes over the past 25 years linked to higher temperatures.

The UW scientists analyzed the life histories of 65 species of aphids, flies, wasps, beetles and other insects, many of them agricultural pests. They found species best adapted to warmer conditions breed more prolifically than their cooler-adapted kin. And not by just a small margin. A 5.5-degree Fahrenheit increase in temperature could mean the difference between aphids that produce 300,000 offspring in two months and those that crank out more than 1 million babies during the same interval.

But not all insects will flourish as temperatures rise. The researchers are working now to figure out which species will be winners or losers.

With fish on the decline and bugs on the upswing, might people be forced to change their eating habits?

"I've had termite curry in Africa," Huey said. "The curry was great. The termites weren't particularly tasty."

Sandi Doughton: 206-464-2491 or sdoughton@seattletimes.com