Sunday, July 31, 2011

Monarch and Viceroy Butterflies

 Viceroy butterflies taste good, to those that like to eat butterflies.  But they don't want to get eaten.  And time has favored those that look more like a Monarch butterfly to not get eaten as often, so today we have a Viceroy butterfly that looks more and more like a Monarch butterfly with each passing generation.  Evolution at work.

I took these photos today in Springbrook's south prairie about 100 feet apart from each other.
This Monarch tastes terrible because the caterpillar below eats milkweed leaves that are very bitter.  After trying to eat one most predators will not try to eat a second Monarch, and most are fooled into thinking the Viceroy is also a Monarch.  Mimicry works!

The Viceroy's hind wing stripe is not present on the Monarch as you can see in this picture.  This is a male Monarch, identified by the black "scent pouches" along the inside vein on the hind wing.  But the two butterflies do look a lot alike. 
The Monarch caterpillar chews a notch in the middle vein on the underside of a milkweed leaf so the leaf will fold down.  Then the caterpillar hangs from the underside and eats the leaf in relative hiding.  But the bright colors on the caterpillar tell all predators that it tastes bad and will make them sick if they eat it. 

This caterpillar was on the east end of Springbrook's south prairie this morning, shaking the raindrops off from last night's storms and eating as fast as it could.

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