For the first time, scientists have found evidence that global warming may be influencing an organism's genes. New research shows that over 30 years, one mosquito species' winter dormancy period --a genetically controlled trait--has shrunk as Earth has warmed.
Mosquito larvae feel the heat.
CREDIT: D. L. COHRAN-STAFIRA
The mosquito Wyeomyia smithii spends its early life in the water-filled leaves of the pitcher plant. Larvae become dormant before dangerous cold weather hits and wake in the spring after the threat of frost has passed. In order to anticipate future temperature, the larvae monitor day length. In the early 1970s, biologist William Bradshaw of the University of Oregon, Eugene, demonstrated that the insects are genetically programmed to wake up after specific periods of exposure to light.
In the 6 November early edition of the Proceedings of the National Academy of Sciences, Bradshaw reports that global warming has shifted the mosquito's schedule. Comparing larvae collected in the field in 1972 and 1996, he found that more recent mosquitoes require 14 fewer minutes. That suggests that the mosquitoes have adapted to spring weather that is arriving earlier than in the past.
Bradshaw's study is "very impressive" because it ties a clear genetic trait to warming trends, says biologist D. Liane Cochran-Stafira of Saint Xavier University in Chicago.
