MSU Extension:
The monarch butterfly, Danaus plexippus, is one of the most widely recognized butterflies in the United States. Its fantastic spring and fall migrations capture the attention of all who appreciate the marvels of nature. Because of the great interest in this creature, any year in which the population seems to be lower than normal raises the attention of the public. The number of monarch butterflies in Michigan at this point in 2013 appears to be far lower than usual, and there are a couple of good explanations.