How High is a Butterfly and a Bit About Global Warming

A couple of my students asked me before I left for Vietnam if I knew how elevation affected the butterflies. According to the prevailing theories about global warming which are based upon the systematic observation of mountain habitats, some species at certain elevations have been moving to higher elevations on an average of 20 feet per decade. This means that as temperatures rise, these organisms move to higher elevations where it is cooler. This change has a profound impact on all of the organisms that live in these habitats. In particular, the butterflies may be very sensitive to temperature and, consequently, move further up the mountain until they reach an elevation where the temperature is right for them. Lien has set up transects at 900 meters and 1400 meters. He wants to see if certain butterfly communities migrate in response to rising temperatures. He suspects this has already happened in the case of certain butterfly species which have disappeared from the area.


How to Spot a Butterfly

Spotting butterflies and identifying butterflies takes a certain amount of skill and experience. I’m sure you’ve seen butterflies fluttering around a field or through the woods, but have you tried to chase them down and catch them. Try it some time. Butterflies have compound eyes, which are very efficient at detecting motion, much more so than ours. In a sense, they see you coming before you do. In order to be effective researchers on this study I have to become very efficient at spotting butterflies and identifying them while they are flying. In order to do this I need to understand what I am looking for. For example, if I know what the behavior of certain butterfies are, such as if they fly high or low, I can tell the difference between a Appias albina (high flyer) and a Pieris canidia (low flyer) which are both white and about the same size. We also need to know about their size, shape, and color. In order to become more familiar with them we need to catch them. If we are able to bring a butterfly up close for a more in depth examination of its markings and colors we can better identify it while it is flying.