The Effects of Extreme Temperatures on the Declining Western Danaus Plexippus (Monarch Butterfly) Population

Abstract

The Western Monarch butterfly population encounters several threats to survival during their migration, including severe weather, human interference, inadequate milkweed availability, and unstable temperatures. However, the recent changes in regional temperatures resulting in part from the increase in global temperatures has been one of the main causes for the significant population decline over the last few decades. Monarchs are a key pollinator and have emerged as a model species for studying long-range migration. Considered to be on the verge of extinction, Western Monarch survival depends in part on acquiring a better understanding of the ways temperature affects them during their life cycles and migration. In this study, the relationship between extreme temperatures and the decline of the Western Monarch butterfly is examined. Using Monarch population data and historical weather data, a multiple linear regression is performed that captures 81% of the variance of the Monarch population. Furthermore, a five- and ten-year survival rate is calculated to determine the possibility of extinction. While a comprehensive forward analysis is unable to be explored in this study, several implications regarding current climate model projections are discussed