Moth Mingle sheds light on diversity of winged insects

            When most people think about moths, it’s the pest species they imagine, like the caterpillars of gypsy moths and winter moths that have defoliated area trees in recent years. But those invasive species are hardly representative of the immense diversity of native moths that inhabit the fields and forests of Rhode Island. An event last week in Kingston demonstrated exactly that.

            Dubbed the Moth Mingle, the annual public program hosted by the Rhode Island Natural History Survey brought a small group of moth aficionados, as well as the merely curious, to URI’s East Farm for a late-night spectacle of creatures great and small that inspired wonder and amazement.

            According to David Gregg, director of the Natural History Survey and the host for the evening, the Ocean State is home to about 1,000 species of moths, and they play an important role in the ecosystem as pollinators and as food for birds and other animals.

            “When you see a lot of species diversity like that, it’s reflecting a lot of complexity in our ecology,” Gregg said. “So if you want to monitor the health of the environment, you should direct

Checking out the bait trap at the Moth Mingle (Photo by Renay McLeish)

your attention at groups with a lot of biodiversity because it will capture a finer grain picture.

            “Moths are also declining in number – we know that from monitoring events like this one – and we don’t know why,” he added. “So it’s something we need to pay attention to.”

            Most moths only fly after dark, some for only a few hours well after midnight, so the action at the Moth Mingle didn’t really get started until complete darkness had set in. By then, several simple strategies were in use to attract moths.

A large white sheet hanging vertically in a field was illuminated with a light bulb. Two other bulbs – an incandescent and a compact fluorescent – illuminated opposite sides of a piece of white cardboard in an experiment to determine which type of bulb attracts the most moths. In the nearby woods, a bucket trap with a black light was deployed to capture whatever flying insects were nearby, and a bait made from overripe fruit, brown sugar and red wine was smeared on several tree trunks to attract hungry moths in search of a meal.

Throughout the evening, the headlamp-wearing participants wandered back and forth from sheet to bucket to experiment to bait-smeared trees to observe the moths, try to identify them, and learn what they could about each species.

Alex Baranowski, a recent University of Rhode Island graduate who describes himself as “an insect person,” has been interested in moths since childhood when he collected and reared moth caterpillars at his home in Bristol, Conn. He was one of the most knowledgeable participants at the Moth Mingle, happily identifying moths and discussing their natural history.

“I’m not sure why I’m so into moths,” he said. “I’m just fascinated by them. They’re this large successful group of insects that occupies just about every role in the ecosystem possible. Some eat plants, some are predatory, some feed on decomposing insect material, some are parasites, and some are adapted to eating food and grain that people have stored.”

By 9:30, moth activity had begun to pick up. A tiny black-and-white patterned moth called a Hebrew clung to the bucket trap as several tan-colored grapevine loopers fluttered around it.

“There are two kinds of grapevine loopers, but only they can tell them apart,” Gregg said. “Their coloration tells you that moths are bird food – they’re trying very hard to convince you that they’re just a leaf.”

At the sheet, a dozen varieties of moths perched beside tiny beetles, stink bugs, grasshoppers, caddisflies and other insects that had been attracted to the light. A slug moth the size of a pencil eraser was dressed in pink and pale green with furry legs. A few inches away was a skiff moth in shades of chocolate and chestnut. A moth with a checkerboard pattern inspired a bit of debate over its identity, while a rice-sized orange and white moth was found to be a leaf miner.

Cindy Sabato of Wakefield attended the Moth Mingle simply out of curiosity. She said it was a way to learn more about the insects that were attracted to her porch light.

“As humans, I think we tend to be less afraid of what we understand, and I love facing and becoming friends with things that make me uncomfortable,” she said as she pointed out a moth she thought looked like lace. “The experience was great. I was fascinated by the many types and shapes and sizes of moths.”

Later in the evening, moth numbers and diversity continued to increase at the sheet, but the two-bulb experiment wasn’t attracting many moths at all, perhaps because its location was in a breezy area that may have discouraged moths to fly. The bait sites also had few moths, though that was expected.

“Only half of moth species eat as adults,” Baranowski informed the group. The others only eat as caterpillars. In addition, many of those that would be attracted to the smell of the bait don’t usually become active until closer to 2 in the morning, he added.

Back at the sheet, Gregg asked the group, “Who wants to see a moth’s eyes glow?” As expected, all of the participants did. After everyone got their turn to see the tiny reflection of a moth’s eyes in his flashlight, Gregg said, “humans are simultaneously curious and frightened of things in the dark. So we turn on a light and we find that they’re cool.”

At the event’s conclusion, Sabato was pleased to have learned so much about moths. “I most certainly walked back to my car feeling less afraid of being hit up by flying insects in the night than when I went in,” she said. “So mission accomplished.”

This article first appeared in the Independent on July 26, 2018.