Pretty in pink

Natural History, June, 2003 by Gary Noel Ross

Like most other katydid species, the western round-winged katydid (Amblycorypha parvipennis) is normally green. But throughout its range, from South Dakota to central Texas, both pink and yellow variants occasionally pop up. My pink lady--for this was a female--was still a wingless juvenile when I came across her one early June morning in western Missouri's Wah' Kon-Tah Prairie. To get better acquainted with this rarity, I placed her in a terrarium.

Then I began to worry--the insect wouldn't feed on the greens I offered her, all prairie grasses and leaves that should have appealed to a katydid. But then, observing that her color was well matched by the pale purple coneflower, I offered her a bloom. She immediately began to nibble on the petals.

After a few days I tried an experiment to see if she got her pink pigment from the flowers: I started her on a diet of yellow blooms. But even though she feasted on yellow for the rest of her two-month confinement, I found no hint of jaundice. Apparently the color was in her nature, not her nurture. Ongoing research on related species, by David A. Nickle, an entomologist with the USDA's Agricultural Research Service, and others, is untangling how katydid color variation is genetically determined.

Why a pink (or yellow) katydid? My guess is that the variants, adapted to feeding on diverse kinds of flowers, help a katydid species enlarge its niche. The color camouflage is simply a tool the insects need to survive.