Redeemer University College Science News

Friday, September 7, 2007

Monarch Butterfly

Monarch Butterfly
The Monarch Butterfly is found throughout Canada in areas where the host plant Milkweed is found.

Monarchs east of the Rockies migrate to central Mexico. Frederick Urquhart of the University of Toronto discovered the first Mexican wintering site in 1974.

The lifespan of most Monarchs is less than two months but the last generation of the summer enters into a non-reproductive phase known as diapause and may live up to 7 months. It is during diapause that the butterflies make the long migration south. The generation that over winters generally does not reproduce until it leaves the over wintering site sometime in February and March. It is the second, third and fourth generations that return to Canada in the spring.

As a defense against predators Monarchs are foul tasting. Whether the butterfly is toxic depends on the species of milkweed the caterpillar was reared on. The common milkweed is nonpoisonous but other species of milkweed contain deadly cardiac glycosides.

No comments: