My name is Heidi. I am long-time reader, first time blogger here on Butterflies and Science. Jessica and I have been collaborating on the Colorado Colias work for the last few years now. While Jessica gets to play with the cute caterpillars, I chase the adults around and try to figure out how they are responding to the increasing temperatures at high elevations in the Rocky Mountains.
Because our lab (http://www.unc.edu/~lbuckley/lab/pmwiki.php) is primarily concerned with how organisms are responding to climate change via morphology, physiology, and life history, I think a lot about evolutionary responses to environmental pressures. One of the best examples of this comes from the industrial revolution. The peppered moth is endemic to the British Iles survives as an adult by being a twig mimic. While there have always been two main color morphs of these moths (a lighter and a darker one), the lighter morphs historically survived in greater numbers as their speckled pattern helped them blend in with the lichen on the tree bark and avoid. During the industrial revolution, pollution in the form of soot settled out of the atmosphere in the canopy of the trees and washed down the bark during rainstorms killing the lichen that covered the bark. This effectively darkened the bark which, in turn, created an environment that was more hospitable for the darker morphs where as the lighter morphs stuck out like a sore thumb and were quickly gobbled up by their avian predators.
While greenhouse gasses are not as easy to see as industrial soot and the evolutionary response to atmospheric warming may not be as immediate, clear examples of how species are responding to warming are needed to inspire reform. Our work with the high elevation species of Colias meadii holds the potential to do just that. By tracking traits in the field (specifically wing melanin which determines how quickly these guys can heat up and fly) and comparing current populations to museum specimens, I am hoping to be able to detect a change in mean trait value over time in response to warming. Below is a schematic of the area of the wing we are looking at.