27 Jul
2014

Posted in: BioBlitz, Caterpillars of Eastern North America, Franklin Farm, Light pollution, Moth Mingle, Moths, National Audubon Society, National Audubon Society Field Guide to Insects and Spiders, Natural Science, RINHS, Roger Williams Park Zoo, Uncategorized, URI, USFW
By Hugh    2 Comments

The Mid-Summer Moth Mingle

Azalea sphinx moth

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If moths and butterflies thought like human children, they would be embroiled in a never-ending case of sibling rivalry. “Why do the butterflies get all the attention?” the moths would moan. “People never even notice us!” The conversation may be whimsical, but surely the moths have a point. Butterflies are the show-off older sibling: gregarious, flashy, turning heads wherever they go. Moths are the younger, early adolescent: sullen, seemingly unappreciated, preferring the dark. Both moths and butterflies are members of the order Lepidoptera, the second largest order within the class Insecta. Yet the average person is likely unaware of the intimate relationship between the two creatures. Lucky for the moths, there are people like David Gregg, Executive Director of the Rhode Island Natural History Survey (RINHS), who derive great pleasure from introducing people to these underappreciated “younger” siblings.

RINHS Executive Director David Gregg prepares a light trap, intended to lure moths.

The setting for Gregg’s introduction is Franklin Farm Historic Farm and Homestead in Cumberland. The 65-acre parcel is operated by a non-profit organization that raises vegetables for local food pantries, as it preserves the 19-century structures on the premises (www.franklinfarmri.org).The event, dubbed a “Moth Mingle”, is part of the RINHS “20 Memorable Events for 20 Memorable Years”, a series of programs celebrating the natural world that are open to the public. (Learn more at www.rinhs.org .)
A crowd of participants, from small children to adults, has gathered on this calm, humid night to see these mostly nocturnal animals. As the sun begins to set, Gregg addresses the gathering. “There are between two and three thousand moth species in Rhode Island alone,” he tells the group, “and about 11,000 in North America. One of the interesting things about them is that each species has one specialized characteristic so that they don’t compete directly with another species.” Gregg explains that moths are usually rather stocky and fuzzy. Their antennae can be feathery, or straight, hair-like appendages. He displays two glass covered wooden cases that comprise his own collection of moths. While the notion of collecting (and therefore killing) creatures may seem at odds with preservation to some, Gregg explains that limited collecting has no major impact on the population, and that the benefits of having the moth in hand outweigh the drawbacks.

Moth Mingle attendees climb through the fields of Franklin Farms to set a light trap.

As the introduction ends, it’s time to set out the various attractants. First, the crowd follows Gregg over the open fields to the farthest corners. Helpers carry a car battery, along with a contraption consisting of a five gallon bucket and short fluorescent lights. As he begins to assemble the pieces, Gregg explains that this is a light trap, designed to attract moths to the particular spectrum of light emitted by the bulbs. Once there, the moths will flutter close to the lights, and eventually fall into the bucket, where a chemical solution will insure that the moths remain for later collection and identification. The overcast skies, the humid, calm conditions, promise good collecting, despite the slightly cool temperatures. Two of these light traps will be placed on opposite ends of the farm, with the hope of attracting different species of moths.

Emerald moth (photo: David Gregg)

Despite the common knowledge that most moths are attracted to light, Gregg says that the precise reason for the interest remains a mystery. “There are only theories,” he explains. “One thought is that perhaps moths navigate by the moon. They are extremely sensitive to even the most subtle pheromonic stimulus (pheromones are the chemicals spread by a female that tell a male that she is available for mating). It’s possible that this sensitivity, when coming in contact with artificial light, results in their becoming overstimulated.” Gregg goes on to explain that moths in general are in a state of decline, and one possible reason is the proliferation of artificial light. Street lights or porch lights that are left on all night attract the moths. In turn, bats and birds key in on these areas, wiping out moths in far greater numbers than they might ordinarily.

David Gregg, along with a gaggle of future lepidopterists, pauses to paint a post with a pungent moth attractant.

On the return to the farm buildings, Gregg pauses to paint trees and posts with a special concoction. The mixture is a blend of overripe apples and blueberries, maple syrup, and beer, among other ingredients, all designed to attract moths that are less stimulated by the light traps. Using beer and yeast simulates the alcohol that rotting fruit produces naturally. It is a pungent mixture, and is quickly detected by the smaller human noses that romp through the fields as the process takes place. “Whoa! That stuff stinks!” they yell as they mill around, not unlike the moths the bait is intended to attract.

Using a sheet lit by an intensely bright light, participants observe winged visitors.

The final technique is headquartered at the farm, and involves hanging an oversize bulb next to a bed sheet, draped clothesline-style from a rope. Like the fluorescent light traps, this bulb projects light in the spectrum that is thought to attract moths. As they flit and flutter around the light, they land on the sheet. This in turn allows Gregg and the rest of the visitors the chance to make some immediate observations. It isn’t long before the sheet is covered in a wide variety of winged creatures, including moths, beetles, and even grasshoppers. As they crowd around the sheet, some of the children inadvertently play resting perch for the moths as well.

Between the three methods of observation, some three dozen species of moths are recorded. Gregg considers that a mediocre showing, but for the lay people who comprise most of the visitors, it is a wide variety. Included in the list is a type of Sphinx moth. Members of this species are large in size, and some are capable of flying up to 25 mph. They are so fast that they actually generate heat, according to Gregg. Another, more delicate visitor is the Emerald moth, which seemed quite content as it lays its pale green wings flat against the porcelain light socket by the sheet.

The night rolls on, and gradually it seems that the youngest lepidopterists in the group have departed the farm to indulge in moth dreams. While the adults drift back to the outer boundaries to check the two light traps, a sudden eruption of coyote howls punctures the night silence. A pack of perhaps half a dozen are quite close by, and seem to have come upon some nocturnal nourishment. They bark and howl, but as suddenly as the tempest began, it ceases. They remain unseen, and the group can only speculate as to what precisely happened just beyond the glow of the light trap.

A member of the Tiger moth family.

David Gregg and others pause before dismantling the light traps. He stretches his lanky frame on the grass as the small group discusses the world of moths. “I remember many years ago an over-eager 15-year-old who was so enthusiastic that he was given the chance to work with actual experts in the moth field.” “Was that 15-year-old you, by any chance?” someone asks. “Yes indeed,” Gregg says with a smile. “That’s why I love seeing kids come out to these things. You never know where the next moth expert is going to come from.”