Over 40 percent of the monarch butterflies in two of Mexico's overwintering colonies died in a storm that struck between March 7 and March 11, 2016. The team analyzing the damage was led by Lincoln Brower, Ph.D., research professor of biology at Sweet Briar College. Far more than the estimated 7 percent mortality rate.
The storm was a severe combination of rain and snow with strong winds and sub-freezing temperatures. Several thousand firs in the Monarch Butterfly Biosphere Reserve were downed. Typically, the dense forest creates a favorable “microclimate” for the monarchs, protecting them from extreme weather exposure. The prolonged severe storm destroyed the microclimatic protection led to freezing in the colonies. The team hopes to carry out more effective methods of analyzing the damage because they are concerned that the current methodology of reporting only total colony areas is underestimating the true decline of monarchs overwintering in Mexico. If more accurate analyses can be made, the more government action will be taken to protect the monarch butterflies. Read more about this story at Entomology Today.