Last Saturday the Wissahickon Nature Club celebrated its 70th anniversary with a picnic and nature walks at Mingo Creek County Park.
I was fascinated by the butterflies we saw because most of them are mysteries to me. I'm able to identify only a handful including this mimic of all mimics, the Viceroy.
In northern North America(*) adult Viceroys closely resemble Monarch butterflies because Monarchs are poisonous. The Viceroys who don't look poisonous are eaten. Those who do, live and reproduce. This predatory pressure reinforces mimicry generation after generation, a form of evolution in action.
How closely does a Viceroy mimic a Monarch? I've marked a photo by Marcy Cunkelman with an arrow showing the black "smile" on the wings that tells the difference. Viceroys have it, Monarchs don't.
Viceroys are even mimics in the larval stage. Their caterpillars look like bird poop on a stick, as you can see on this one found by Dianne Machesney. Not only does he look like poop but I think those obvious antennae are false. Aren't they at his back end?
Click on the photo above to see an even "poop-ier" looking Viceroy caterpillar.
No matter what life stage, these butterflies are not what they appear to be.
(perched butterfly photo by Chuck Tague, photo with arrow by Marcy Cunkelman, caterpillar photo by Dianne Machesney)
(*) Where Monarchs are rare in Florida, Georgia and the Southwest, Viceroys mimic the Queen butterfly.