North America’s beloved Monarch butterflies are known for their annual, multi-generation migrations in which individual insects can fly for thousands of miles. But Monarchs have also settled in some locations where their favorite food plants grow year round, so they no longer need to migrate. A new study of specimens collected over the last two centuries shows how wing length evolves in response to migration habits.
Click here for original story, Two centuries of Monarch butterflies show evolution of wing length
Source: ScienceDaily