Warm Weather and Butterfly Populations

from Fermilab Today, 19 March 2012:

Spring doesn't officially begin until Tuesday, but we've been enjoying spring-like weather for weeks. Could there be any possible downside to this? Maybe.


Human beings are not particularly sensitive to subtle changes in our environments because we are highly buffered from their effects. If the temperature changes, we can just turn the heat or air conditioning up or down and go about our business. But some species of animals are very susceptible to small changes in their surroundings.

A recent Science360 article reports that this early spring is hurting the Mormon Fritillary butterfly in the Rocky Mountains. Warmer weather has led to earlier than normal snowmelt in the mountains, which decreases the number of nectar sources for the butterflies, resulting in females laying fewer eggs. If the snow cover disappears early again, the overwintering larvae will be exposed to potentially deadly frosts.

These cascades of cause and effect are central to understanding the science of ecology. The complex interactions between climate, weather, butterfly and flower populations have evolved over time to rely on precise timing of events, and when that timing is disturbed, unexpected consequences can multiply.

In the insect world, butterflies are very sensitive to environmental factors, and although we don't have Mormon Fritillaries locally, we do have many species of butterflies. At Fermilab, about 54 species have been observed. Becoming familiar with them and learning to pay attention to them can make us more aware of the subtle design in the environment around us. You can also use your butterfly identifying skills to help naturalists track the health and migration species populations.

If you are interested in learning about local butterflies and helping track their health, consider attending the butterfly monitoring workshops led by Fermilab's Tom Peterson. The free workshops are sponsored by Fermilab Natural Areas and the Illinois Butterfly Monitoring Network. The beginner's class is from 10 a.m. to noon on Saturday, May 5, and the intermediate class is from 10 a.m. to noon on Saturday, June 2.

—Rod Walton, Fermilab ecologist (and FNA President)