Charles Davis of Vineyard Haven got right to the point. 

“Any idea what this is?”

His inquiry concerned a moth he had observed resting on the shingles of his house for a few days. He describes this furry flyer as “stunningly beautiful” and shared that after taking a picture, he gently touched its fuzzy body and it flew away.

The point would not have been obvious to Charles, since the species in question was a spiny oakworm moth and its name results from the spines found on the caterpillar stage of this species, which was not the life stage he observed. Even if he had seen its caterpillars, its spines are not of the stinging or irritating variety, like many prickly caterpillars.

A striking species, the spiny oakworm moth boasts a pink-orange body and wings, bright white solitary spot on each wing and black freckles on the wings. The white spots inspired this insect’s scientific name — Anisota stigma — with stigma meaning spot. Anisota is broken down into anisos, or unequal and ota, which is a common taxonomic suffix.

This moth is one of three types of oakworm moths found on the Island, which additionally include the pink striped and orange striped oakworms. All feed primarily on oak trees, though they can also enjoy the leaves of hazel and basswood trees.

Figuratively speaking, these moths are night owls, being most active after dark. They like late night, with research showing that ready-to-mate females release pheromones between one and three A.M.  Interestingly, they wait until daytime to mate with a male and will again hold off until nighttime to lay their eggs.

Oval-shaped yellow eggs are laid in clusters of five to twenty and, after two weeks, these eggs will hatch into caterpillars that initially feed together in groups. Their non-functioning spines may serve as deception, making predators think the caterpillars are more dangerous than they are. As they age, they will go off and feed solitarily until they are ready to pupate. Spiny oakworms overwinter in underground chambers. The moths that emerge will not feed as adults.

Spiny oakworm moths are sexually dimorphic, meaning that there are observable differences between the sexes. Females are larger than males, though males tend to be redder than the females. Added to the color conundrum is the variation that southern Texan spiny oakworms lean toward the browner side of the spectrum.

Look to the antennae for a definitive gender assessment. Female spiny oakworms have filiform—or threadlike—antennae, while the males have antennae that are quadripectinate or comb-like on four sides.

Much more common to our south, spiny oakworm moths are at their northern-most range in Massachusetts and are found mostly in coastal regions of our state. They are known to be relatively abundant on the Islands, South Cape and Plymouth County. 

Common or rare, the spiny oakworm moth disputes the idea that moths are boring. Its Barbie-approved pink appearance and Charlie Davis’s fascination are ample proof of that.

Suzan Bellincampi is director of the Felix Neck Wildlife Sanctuary in Edgartown, and author of Martha’s Vineyard: A Field Guide to Island Nature and The Nature of Martha’s Vineyard.