Have you ever wondered if there’s a National Moth Week? Well—wonder no more—it’s a real thing, and it just transpired on July 18 through the 26th. If you already enjoy “mothing,” (the practice of attracting, observing, photographing, identifying and documenting moths for enjoyment or scientific study), then perhaps you took part in the activities associated with this annual global event as a citizen scientist. (If not, and this interests you, visit nationalmothweek.org to learn more.)

In my last column, River Talk readers learned about leaftier (also known as leafroller) moths and the fernball shelters they construct. In the ongoing celebration of National Moth Week, here are two more interesting moths making their homes in the Upper Delaware River region. 

As its name implies, the caterpillar of the grapeleaf skeletonizer (Harrisina americana) consumes the leaves of various plants in the grape family, including Virginia creeper, leaving behind lacy skeletons that can be observed throughout the region. Bright bands of yellow on the caterpillar and a colorful collar of orange or red on the moth provide a warning to potential predators, as this moth manufactures and releases its own toxic hydrocyanic acid.

The second species described here is the large maple spanworm moth (Prochoerodes lineola). Its caterpillar feeds on a variety of plants and trees such as oak, maple, dogwoods, apple, willow and walnut. Both the moth and caterpillar rely on camouflage to avoid predators. The moth resembles a dry brown or tan leaf with darker markings and a wingspan of approximately 1.5 to 2 inches. Its caterpillar sports a twig-like appearance that helps it blend in with foliage. It is neither toxic nor harmful to humans.

The caterpillars of both moth species depend on consuming leaves for their survival, while the large maple spanworm moth also practices the art of camouflage, thereby helping to protect itself from predators. 

With a full year to prepare for National Moth Week 2027, there’s plenty of time to take photos and make notes of the amazing moths inhabiting our local landscapes!