Monarch on the Move

October 27, 2005


Provided and copyright by: Andrew Yee, ZINC Projects
Summary authors & editors: Andrew Yee

Each autumn, millions of monarch butterflies in southern Canada and across much of the central and eastern U.S. make an incredible journey to Mexico, spending the winter months in favorite roosting spots. Some butterflies will travel up to 5,000 km (3,000 mi) to colonize in a small mountainous area (few hundred acres) of central Mexico. Even more amazingly, the butterflies that make the journey are the great-great-grandchildren of the butterflies that left the subtropics the previous spring, yet somehow they find their way to the same roosting spots -- sometimes even the same trees! Recent research suggests that genetic programming related to the internal circadian clock of monarch butterflies instinctively directs them to use the Sun as a navigation guide to reach their winter residences. This female monarch butterfly (above) is taking a nectar break near the start of her arduous, southbound migration. Photo taken at Humber Bay Park in Toronto, Canada, on September 18, 2005.

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