|University of Kentucky Department of Entomology|
Mystery Bug Answers
Mystery Picture #50
This picture is a close-up of part of an insect.
The Viceroy Butterfly is a mimic. It closely resembles another very common insect, the Monarch Butterfly, that predators find distasteful.
How can you tell the difference? Look at the hind wings of each of the two butterflies pictured below. The Viceroy on the left has a black line that crosses from one side of the wing to the other, whereas the Monarch on the right does not have this line. Although it is hard to see in these particular photos, the Viceroy has only one row of white dots completely within the boundaries of the black wing edges and the Monarch has two rows. Also, the Viceroy's wings are the same shade of orange on both the top and bottom sides of the wing, whereas the Monarch's wings are much lighter orange on the underside.
1. What is the name of the insect that this one mimics?
2. What advantage does this insect have in looking like another one?
By looking like a monarch butterfly (which tastes terrible to predators and makes them sick!), the viceroy (which is a tasty prey) is avoided by predators who have had a bad experience with monarchs in the past.
By the way, the Monarch butterfly acquires its bad taste as a caterpillar when it feeds on the milkweed plant that is its favorite food. The milky sap of the milkweed contains chemicals called cardiac glycosides that make vertebrate predators such as birds very sick. A young bird may try to eat a monarch butterfly once, but after being sick, it will not touch anything that looks like it ever again. Thus, the viceroy butterfly, which is perfectly good food for a bird, is protected by looking like the monarch.
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