Early Snowmelt Decreases Butterfly Population

New research published in Ecology Letters shows that a single climate parameter, the timing of spring snowmelt, has many different effects on the population growth of the Mormon Fritillary butterfly in the Rocky Mountains. Science Daily explains that researchers studied the two-year life cycle of the butterfly and found that early snowmelt in the first year of the cycle led to lower abundance of the butterfly’s preferred flower species, resulting in less butterfly eggs being laid and lower population growth rate. Early snowmelt in the second year of the cycle further decreased the population growth rate, most likely from early-season frosts that killed the caterpillars that emerged from the eggs laid the previous summer. The authors predict that this coming summer will be difficult for the butterflies because the lack of snowpack this winter increases the chance of significant frost damage.