Thursday, March 20, 2008

Goatweed Leafwing

Okay, so here's the scoop on that butterfly I saw hiding from the wind in the dead grass....

It was a male goatweed leafwing (Anaea andria), fall form. The male and female of this species look a little different - the male's wings tend to be "plainer", i.e. with fewer spots, bars, etc., but brighter than the female's wings. Both are basically a shade of brownish-orange, with the fall form of the male being a particularly rich, velvety looking rusty orange with brownish edging.

The underside of the wings of both sexes looks remarkably like a tannish, dry leaf. The butterfly generally rests with its wings folded, so it can be hard to see the brightly colored upper wing surfaces.

The eggs are laid singly on the underside of the leaves of Croton species. Here in Kansas, it would appear that there are 3 larval plants: Woolly croton or hogwort (Croton capitatus), Texas croton (Croton texensis), and Prairie tea (Croton monanthogynus). When the caterpillar is little, it rests on the midrib of the leaf it is eating for camoflage. As the caterpillar gets larger, it first folds, then wraps a leaf around itself to remain hidden.

The adults feed on rotting fruit, sap, bird droppings, and dung.

This species overwinters in its adult form. They have from 2-4 generations/year, depending on how far north they are. (Goatweed leafwings are found as far north as South Dakota and southern Michigan, and as far south as central Florida, southern Texas, and northern Mexico.)

A last interesting note: One site mentions that the adults play dead when handled. Another site talks about how the young caterpillars attach fecal pellets to their backs and the midrib of the leaf they are eating, probably to keep ants and other predators at bay. These behaviors, along with their camoflage coloration and behavior as larvae and adults, makes this butterfly species a good example of several types of predator evasion.

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