News & Views

The monarch butterfly (Danaus plexippus) creates one of nature’s most amazing wildlife spectacles - the sight of millions of these butterflies migrating south for the winter, with the next generation returning back north during the following year.

Recognisable by their lacy orange and black wings, monarch butterflies are famous for their seasonal migration. Each fall, millions of monarchs fly from Canada and the northern USA south to California and Mexico, where they overwinter before heading back in the spring.

Unfortunately however, the numbers of butterflies undertaking these journeys have fallen back significantly over recent years. This has led to attempts to breed them for release, and hopefully boost the overall population in this way. However, a study just published the University of Chicago provides new insights into the effects that raising monarchs in captivity might have on their ability to migrate south at the end of the summer. It goes so far as to caution that some methods could even be having a detrimental impact on the population.

The impact of captive-breeding

Researchers Ayşe Tenger-Trolander and Marcus Kronforst have been looking into how environmental triggers and genetic variation affect the butterflies’ migratory behaviour. Last year, they, along with other members of the Kronforst lab, discovered that a group of commercially bred monarch butterflies seemed to be worse at orienting south than their wild counterparts, spelling trouble for their ability to migrate correctly.