Our insect of the week for September 21, 2026 is Caloptilia rhoifoliella, the sumac leafblotch miner. [LEPIDOPTERA: Gracillariidae]

In keeping with our focus on insects which feed on poison ivy, yes, this is one of the host plants preferred by the caterpillar. As the name implies, the caterpillar hides in plain sight by mining between the upper and lower surfaces of the poison ivy leaf. Later instars of the caterpillar exit their mine and pull the tips of the leaves together into a tight roll. The caterpillar feeds on the leaf within this roll. It creates another roll as it continues its development. Pupation occurs in the final leaf roll. Adults often fly in June and August in central Illinois.

It is thought this species overwinters as an adult. It has also been observed this species is heavily parasitized (typically by wasps).

This species was described by the American entomologist Vactor Chambers in 1876. He spent most of his life in Kentucky and specialized in microlepidoptera.

The specimen in this photograph was collected (and photographed) by Frank Hitchell in Peoria County, Illinois.