Inherit the warmer wind: Some organisms' genes are changing in step with Earth's climate

Abstract

Now, 30 years later, Holzapfel and Bradshaw are married and jointly running a lab at the University of Oregon in Eugene. The couple's attention focuses on one of a bog's typical residents-a tiny mosquito that makes its home inside carnivorous pitcher plants. This pitcher plant mosquito (Wyeomyia smithii) helps itself to insects captured by the plant, digesting parts of the bugs and leaving the rest behind for the plant. Much of the two scientists' work revolves around a phenomenon known as photoperiodicity, in which the mosquitoes rely on day length to determine when to go dormant in the fall. Variations in this trait are controlled by genes. Five years ago, the two scientists got their first clues that the W smithii specimens they'd analyzed while at Harvard weren't quite the same as the ones they continue to capture and study today. Other researchers had already observed that global warming seemed to be changing the actions of some organisms (SN: 3/8/03, p. 152)-animals from birds to butterflies were migrating out of their long-time habitats, and plants were flowering too early or going dormant too late. Some scientists had batted around the idea that not all these changes were superficial-that instead, populations might be responding to global warming by modifying their genes. Holzapfel and Bradshaw remembered that idea one morning over coffee as they flipped through the decades of data they'd collected on photoperiodicity in W smithii. We were totally shocked bywhat we saw, recalls Holzapfel. Photoperiodic time tables, hardwired in the mosquitoes during thousands of years of evolution, appeared to be gradually changing in many ofthe populations-a result, the two scientists say, of warmer temperatures in each population's habitat. Holzapfel and Bradshaw's mosquitoes were one ofthe first organisms in which scientists observed genetic changes that might be attributed to global warming. Other scientists have more recently reported that the genetic makeup of organisms ranging from fruit flies to birds might also be responding to climate trends. Although these adaptations may enable some animals to keep pace with global warming, animals that don't evolve quickly could be at risk.