Since we focused on an insect that consumes poison ivy last week, I thought it appropriate to focus on another unrelated insect which also relies on poison ivy as food while in the caterpillar stages of its life. In this case, I refer to the species Dichorda iridaria, the showy emerald moth [LEPIDOPTERA: Geometridae]. This species was described by the French lawyer and entomologist, Achille Guenée, in 1857. He is remembered as one of the first to describe and classify noctuid moths.

In central Illinois, most adults are encountered from July through September. Adults are often attracted to light at night (specifically light in the UV part of the spectrum). It is most commonly encountered near the edges of forests and woodlands (where the host plant seems to thrive).

Here are some things that are not well known about this rather commonly encountered moth. Where the larva prefers to hide when pupating is not well known. How many generations there are per year is not well known. I have seen records form Illinois of adults in April. This might imply two generations per year, but that has not been confirmed. I mention this because this is clearly a species in need of further study. Which insects parasitize the caterpillar is also poorly known. Yes, the caterpillars prefer a rather noxious (at least to humans) plant making observations a bit more difficult, But this is just one example of many insect species we know precious little about in central Illinois.

The specimen in the photo below was collected in Peoria County, Illinois by Frank Hitchell. He also took the photo.