The first thing you notice about fairy moths are the white, waving, and impossibly long antennae. I’d seen one in the distance before and couldn’t wrap my head around what it could be.
Females in the Adela genus have antennae twice as long as their wings, and male antennae are three times as long. Why the hyperbole? The only explanation I’ve found is that these moths lean heavily on tracking pheromones to find their mates. They also engage in night-time ritual displays, which is the source of their common name. There’s a link below to a picture from Oregon that shows a large group “dancing,” like little Tinkerbells, in a sunbeam.
I put dancing in quotes because according to one researcher from Montana, Adela males use spurs on their legs to injure rival males, and tear their wings, during these shows, which sounds more dangerous than most dancing.
I’m fairly certain these are Adela septentrionella, aka oceanspray fairy moths, the larvae of which feed on oceanspray shrubs. The adults eat nectar from various sources, including daisies and the plant these moths were on, poison oak!
There were three moths when I first approached them, and I only got photos of two of them, both males. In the sunlight, they’re tinted gold. Female oceanspray fairy moths have orange hair on their heads.
The larvae live in portable cases, like little sleeping bags they build around themselves, and I’m sure they’re nearly impossible to find. There are no pictures of the caterpillars that I can find online.
See more of Karen’s work here.
Research on mating behavior: https://inaturalist.ca/taxa/317689-Adela-septentrionella. Accessed 5/31/22.
Picture of a group of fairy moths in flight: https://www.notesfromtheroad.com/roam/fairy-moths.html. Accessed 5/31/22.