Stanford researchers have recently shown that early snowmelts for two consecutive years may significantly affect variations in butterfly population growth rates, demonstrating a link between climate change and insect population.

The research, performed in the Colorado Rocky Mountains, analyzed long-term data on the common Mormon fritillary butterfly, and predicts that this summer will be difficult for butterflies due to a low snowpack.

Early snowmelts caused flowers to bud too soon and subsequently be destroyed by early-season frosts, which result in a loss of the butterfly’s preferred nectar flower. This reduced nectar availability leads to a decline in the number of eggs laid by females for the next year’s caterpillar population.

Carol Boggs, Bing director of the Program in Human Biology at Stanford and the study’s lead author, noted that previous studies have shown a single climatic variable, such as an early snowmelt, can have multiple effects on an organism’s population growth. However, this link had not been demonstrated for species like butterflies that live for one year only.

The National Science Foundation and Stanford’s Vice Provost for Undergraduate Education funded the study. The results were published in March 2012 by Ecology Letters, which is a joint U.S.-French publication, with support by France’s major scientific research center, Le Centre National de la Recherche Scientifique.

— Mary Ann Toman-Miller