Which are the Southerners? The Northerners?

Red-Spotted Purple butterflies photographed by Jeff Zablow

Two of what you see were photographed in Raccoon Creek State Park in southwestern Pennsylvania. Two were taken in Leroy Percy State Park in Hollandale, Mississippi. 980 miles separate these 2 parks.

Ok. Try this. Which images are the Southern (Mississippi) butterflies? Which are the Northern (Pennsylvania butterflies)?

Red-Spotted Purple butterflies (Basilarchia astyanax) are familiar to us through most of the United States, generally from the Rocky Mountains east to the Atlantic Ocean. A huge expanse of territory.

Millions of square miles apart from one another. Surely that much separation produces lots of difference.

The National Audubon Society Field Guide to Butterflies (North America) (Knopf, 2012) advises that “Eastern populations have some red in FW [forewing] tips above. Butterflies of the East Coast by Cech and Tudor (Princeton University Press, 2005) notes that a “series off red-orange marks near the FW [forewing] apex is more prominent in the female.” Is that helpful?

Answer: The top 2 images are Pennsylvania red-spotteds . . . the bottom 2 images are Mississippi fliers.

Jeff