For tonight’s caterpillar, I am featuring the Sphingidae family member, Amorpha juglandis – the walnut sphinx moth. This is the only species in the monotypic genus, Amorpha, a name that is shared with a plant genus that holds our leadplant (Amorpha canescens) and false indigo bush (A. fruticosa). This name comes from the Greek – amorphos- meaning formless or mishappen. This describes the lack of wing and keel petals of the corolla of these beans. For the moth, I am not completely certain, but it may have to do with the unique shape and placement of the rear wings when this moth is at rest. This species is very easily identified in both larval and adult forms.
First up are a couple of early instar brood mates that I found on the same walnut tree in mid-July at Kaintuck Hollow in Phelps County, MO.
Next up is an older cat found at Schoolcraft Prairie in Washington County, MO in mid-August. Caterpillars of this species at this stage are infamous for its defensive displays when harassed, including emitting a high-pitched squeak, thrashing and biting. Unfortunately, this one was pretty chill, so I could not show this off to the folks I was with.
Finally, on the same night we photographed the caterpillar pictured immediately above, an adult male moth was attracted to our blacklight setup. This was my first looks at the adult form of this species.
A Thousand Acres of Silphiums 