WHO LET THE MOTHS OUT
Randy Short, homeowner in Aspendell (pop. estimated 500), has lived in mountain towns all his life.
But never has he seen anything quite like miller moth season in that small foothold of the Eastern Sierra.
“I find it humorous, actually,” said Short who described to The Sheet those trials and tribulations associated with the late spring and early summer in the small community outside of Bishop—one that boasts an elevation even higher than that of Mammoth’s (at 8,409 ft.), and, as it turns out, a much higher per capita population with which to share the views.
“I might open the door to my shed out back, and a couple hundred of them just haul ass out of it,” said Short, who has run the gauntlet through old wives’ tale remedies to control the intruding moths.
“My place was one of the first ever built in Aspendell, and the guy who built it did a really good job of sealing the place up,” said Short. “But if you’re smart, you have a broom (the first line of defense) or a dust buster (the second line of defense) waiting at the storm door to vacuum up the few that make it in … They make an unbelievable mess.”
And while entomologist and University of Nebraska-Lincoln Professor, Randy Lloyd, refers to the millers by their proper, scientific taxonomy—owlet moths—he also concedes that, to the average homeowner, the insect is a “tremendous nuisance.”
As Lloyd explained, the moths that invade Short’s and other homes have reached the adult stage of what’s called a cutworm’s life.
“The name cutworm—the [larva pupate] will actually feed on plants. Cut the vines off tomatoes, cut off corn stalks, whatever. Then, they cut through their little cocoons and emerge as adults; as moths.”
Says Lloyd, the adult moths have a knack for getting into the crevices and the crawl spaces both outside (think splintered tree logs, and gaping rock beds) and inside the gaps of our homes and vehicles.
“You might open your car door,” says Lloyd, “and a dozen pour in… It’s [something] out of Stephen King.”
And to use Short’s terminology, that propensity for “hauling ass” into the spaces they’re least wanted can be explained by the insects’ biochemistry.
According to Entomologist and University of Connecticut Professor, David Wagner, the more specific taxonomy of this species is the spaelotis clandestina—a moth of the family Noctuidae, and one capable of releasing what’s called an aggregation pheromone—an emitted chemical substance used to induce group formation among a species.
Meaning, where one moth leads, others, surely, will follow.
“Particularly if a house has cracks or windows without screens, it’s basically this invisible chemical calling out that there’s safety in numbers; Something that’s saying, ‘Hey buddies, there’s a party in here. Let’s spend the summer together.’”
Says Wagner, after the caterpillars mature in early spring, they hatch from their chrysalises before immediately abandoning the native lowlands from which they mature for higher elevation in the warmer months.
“It’s called estivation—the summer equivalent of hibernation,” says Wagner. “They don’t care about sex. All of their reproductive organs are either atrophied or without hormones. It’s just about getting through the summer until the rains come in early fall, things green up again, and they can migrate back out of the houses and back out of the mountains.”
This moth season peaked in late June/early July.
And then, the moths retreat back to the lowlands. They mate, lay their eggs. The cycle begins anew.
And that “mess” referred to by Short was described by Wagner as a mere byproduct of the estivation phase.
“All they really do is take short flights out to get nectar, or water. Then they’ll often poop or release, you know … liquid excrement. That may stain the walls and plaster,” says Wagner. “So it’s not just seemingly unsanitary, and a little unsightly. It can cause actual damage.”
The moths do not, however, pose any danger to human health.
And, according to Jake Rasmuson—real estate broker and owner of Bishop Real Estate Rasmuson & Associates—they pose no real danger to the Aspendell housing market, either.
“Especially in Aspendell, a lot of houses tend to be vacant because they’re second homes,” says Ramuson. “Moths can pile up inches deep if not taken care of… and all the excrement, too.”
Homeowners, said the broker, must remain cognizant. Cleaning professionals may be called in weekly—even daily—to stay on top of the pests.
“But the good news is that, in Aspendell, we tend to sell a lot of homes around the same time [as the moth season]. People aren’t necessarily shocked … The beauty of the Eastern Sierra far outweighs the small nuisance of moths. If moths are going to keep you from purchasing, it’s probably not the right area for you.”
And for Wagner, however unsavory the miller moth visitation in Aspendell may be for residents, it’s a migratory stage necessary to the continuation of the species; necessary to its limb on the inextricable “tree of life” in this region of California.
“You’ll read about the downside of this species in any newspaper,” says Wagner.
But the upside, he says, is that the sheer number of individuals in these populations provides an abundance of biomass to the Eastern Sierra. Because, as mentioned by Lloyd, moths use their pheromones to aggregate in tight spaces like logs, rock formations, and other abiotic elements of their landscape. There, as a viable source of protein for predatory animals, Wagner estimates that miller moths in peak season are responsible for a greater nutrient energy transfer than any other species in their system.
“The Forest Service has fought these forest pests for 150 years,” says Wagner. “But what we have to do, now, is to stop thinking about these very, very important pests as ‘bad.’
Insect abundance is part of the food chain. It’s how you make songbirds, and baby birds, and mammals, and all the raptors that eat those insectivores… This extraordinary number of what people call ‘millers’ are essential for ecosystem function. They’re essential for the Sierra, and everywhere else.”
