Effect of decreased snowpack on a rare butterfly’s host plant

The most well-known aspect of climate change is global warming. Among other things, Earth’s warming temperature has caused less snow to fall, and snow to melt earlier in the spring. Early melting has been shown to alter the phenology, the timing of life history events, of spring organisms. Phenological shifts caused by climate change can vary considerably between taxa, which can lead to mismatches between interacting species. The frosted elfin (Callophrys irus) is a spring-flying butterfly in the Eastern United States, and is listed a species of concern in 11 states. Host plant specialists, frosted elfin only lay eggs on small yellow wild indigo (Baptisia tinctoria) and wild lupine (Lupinus perennis), and are especially vulnerable to climate-induced mismatches. To simulate the impact of global warming on frosted elfin host plant, we conducted a snow removal experiment at Gavins Pond (Foxboro, MA, USA) where small yellow wild indigo is abundant, but the frosted elfin population is declining. In December 2021, we set up five plots of each of three treatments: snow-removal (shoveled), trample-control (plot walked on with snowshoes), and control (untouched). In each plot, we tracked temperature and timing of indigo leaf out/development relative to the current frosted elfin flight season and larval developmental period (April – July 2022). Beyond shifts in physical presence of plants, phenological shifts may also affect the nutritional content of the larvae’s sole food source. We also sampled leaves from each treatment for carbon and nitrogen analysis.