Monarch¹ butterflies have long been admired for their sense of direction, as they migrate from Canada and the United States to Mexico. According to new findings from a team of scientists, including researchers from the University of Guelph, the winged insects fly without a map, and use basic orientation² and landmarks³ to find their way to their wintering sites, thousands of miles away. Recently published in the Proceedings⁴ of the National Academy of Sciences, the study examined the insects' flight patterns and whether those patterns changed when the butterflies were displaced.

 

The team, which included researchers from Queen's University, Germany and Denmark, also analyzed⁵ more, also analyzed more than 50 years' worth of migration⁶ data to learn how monarchs⁷ find their way for the first time to their wintering habitat in Mexico.

 

A monarch flies the full migration route just once during its life cycle.

 

The flight patterns and data suggest that, when butterflies are blown off course（被中断）, they likely use major geographic⁸ landmarks to funnel⁹ them to their destination.

 

Looking at the distances that these insects fly each year, scientists had long thought that monarchs were "true navigators."

 

"To be a true navigator, you need both a compass and a map," explained Prof. Ryan Norris, Department of Integrative Biology. "We've know for some time that monarchs use external cues, such as the sun and magnetic field, as a built-in compass that can indicate their latitude¹⁰. But having an internal map requires knowledge of both latitude and longitude¹¹."

 

To test whether monarchs could detect longitude displacements¹², the team, led by U of G undergraduate student Rachael Derbyshire, examined the butterflies' flight patterns in a funnel on the University of Guelph campus. They then tested the same monarchs in Calgary.

 

"The monarchs we tested in Guelph flew southwest, in the general direction of Mexico," said Derbyshire. "When we tested them in Calgary, they flew in the same general direction as if they were in Ontario, suggesting that they did not know they had been displaced 2,500 kilometres."

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