Photos by Lukas Keras.

Ecological research has been central to Highstead’s mission since its founding some four decades ago. So, while it’s not unusual to see scientists working in Highstead’s woods, it is unusual when that research is being conducted by a junior in high school. And it’s even more unusual when the subject of the study is—drumroll, please—moths.

That’s right, moths. You know, those little bugs famous for turning sweaters into Swiss cheese.

But to Lukas Keras, moths are fascinating creatures, and surprisingly understudied, especially compared to their more popular butterfly cousins. Only 16 years old and already something of a lepidoptera expert, he spent the better part of last year surveying and documenting the moth species that call Highstead home.

Lukas Keras used several methods to survey moths at Highstead, including this light trap.

Scientists have described a staggering number of moth species worldwide—more than 160,000; nine times the number of butterfly species. Connecticut is home to over 475 species of moths; Keras found 401 at Highstead. Still, there are likely species that have yet to be discovered, and more to learn about the known species.

“There are many moths that nobody knows what the caterpillar looks like or what it feeds on,” he says. “You literally could discover something new in your backyard.”

Keras grew up in an outdoorsy family who cultivated his love of nature from a young age. “I’d spend summers outside catching bugs and eventually I learned how to identify them and which plants they’re associated with,” he says. “It fascinated me that there’s that much out there. Even if you’re not discovering something new to science, it always feels like a discovery when you find something that you’ve never seen before. That has always really attracted me.”

In 2022, Keras discovered the first tearful underwing moth (Catocala lacrymosa) ever recorded in the state of Connecticut. Later that same day, he found the first sad underwing moth (Catocala maestosa) in Fairfield County. The specialization of each species—whether it’s their dependency on a specific caterpillar host plant or distinct behavioral traits—can make it difficult to find and photograph moths, he says.

BLINDED SPHINX MOTH CATERPILLAR This caterpillar was found on White Meadowsweet (Spirea alba) at Highstead.
BLINDED SPHINX MOTH CATERPILLAR This caterpillar was found on White Meadowsweet (Spirea alba) at Highstead.
BLINDED SPHINX MOTH (Paonias excaecata) This beautiful species can be difficult to photograph because adults are active very late at night. At Highstead, where they are common, individuals were never attracted to the lights before 2 a.m.
BLINDED SPHINX MOTH (Paonias excaecata) This beautiful species can be difficult to photograph because adults are active very late at night. At Highstead, where they are common, individuals were never attracted to the lights before 2 a.m.
PINK STREAK MOTH (Dargida rubripennis) This is the rarest species Keras found at Highstead. It is listed as a species of special concern in Connecticut.
PINK STREAK MOTH (Dargida rubripennis) This is the rarest species Keras found at Highstead. It is listed as a species of special concern in Connecticut.
LUNA MOTH (Actias luna) There is likely a reproducing population of luna moths at Highstead given the abundance of the larval food plant (hickory) and the multiple individuals observed during the survey.
LUNA MOTH (Actias luna) There is likely a reproducing population of luna moths at Highstead given the abundance of the larval food plant (hickory) and the multiple individuals observed during the survey.
CROWNED SLUG MOTH (Isa textula) This is among Highstead’s most unusual caterpillars. Slug Caterpillars lack prolegs (the many "feet" most caterpillars have) and, as a result, they glide across a leaf on a bed of silk. It is flattened and bears many spines on the edges, giving it the appearance of a crown when viewed from above.
CROWNED SLUG MOTH (Isa textula) This is among Highstead’s most unusual caterpillars. Slug Caterpillars lack prolegs (the many "feet" most caterpillars have) and, as a result, they glide across a leaf on a bed of silk. It is flattened and bears many spines on the edges, giving it the appearance of a crown when viewed from above.
SADDLEBACK CATERPILLAR (Acharia stimuli) This is one of Connecticut's few venomous caterpillars. It is relatively uncommon in the state; only two caterpillars of this species were found at Highstead.
SADDLEBACK CATERPILLAR (Acharia stimuli) This is one of Connecticut's few venomous caterpillars. It is relatively uncommon in the state; only two caterpillars of this species were found at Highstead.
BROWN-HOODED OWLET MOTH (Cucullia convexipennis) Many caterpillars that feed on poisonous plants have bright, flashy aposematic or "warning" coloration. While the Brown-Hooded Owlet is not known to feed on poisonous plants, birds that have learned to avoid the vibrant aposematic toxic caterpillars may avoid eating these brightly colored caterpillars as well.
BROWN-HOODED OWLET MOTH (Cucullia convexipennis) Many caterpillars that feed on poisonous plants have bright, flashy aposematic or "warning" coloration. While the Brown-Hooded Owlet is not known to feed on poisonous plants, birds that have learned to avoid the vibrant aposematic toxic caterpillars may avoid eating these brightly colored caterpillars as well.

Keras uses several methods to survey moths, the most common being a simple UV light and bed sheet. Moths see in ultraviolet light, so lamps with a higher UV output, like the mercury vapor lamps Keras uses, work best for attracting moths. He also assembles bucket traps filled with cardboard and egg cartons that he leaves out overnight. Moths, attracted by the UV light, become “trapped” in the bucket and nestle into the cardboard for the night.  In the morning, Keras picks up the bucket and photographs the resting moths.

“The good thing about the overnight light traps is it captures stuff you might have otherwise missed, including the moth that’s flying at 4 a.m.,” he says.

“Even if you’re not discovering something new to science, it always feels like a discovery when you find something that you’ve never seen before.” Lukas Keras

Keras also uses fermenting fruit and molasses, which mimics tree sap, to attract moths that are not drawn to light.

“There are a lot of species that can’t be attracted by light but can be attracted by these fermenting fruit baits, and the other way around. Several moths don’t feed as adults at all so you’ll never find them with bait, but you will find them with a light trap survey,” he says. “That’s why it’s important to use both methods when you’re conducting a survey like I did at Highstead.”

Other moths may be found either free-flying or during their larvae stage. “If you walk through the woods in the right season with a UV flashlight, the caterpillars will glow and you can pick them out,” Keras says. “I found a lot of species at Highstead using the UV flashlight.”

Keras sampled the same sites at Highstead several times a month between May and November. “It’s important to do a season-long survey,” he insists. “The more you go to a site, the better you understand what species are there.”

One key to discovering moths is to locate their caterpillar host plants, species-specific plants upon which developing larvae depend. Put simply, without the host plant, you will likely never find the moth. The relationship between a particular species and its host plant can be very specific, say, a host plant that is growing in a wet area, or on a well-drained slope. Take, for example, the huckleberry sphinx moth (Paonias astylus), which feeds almost exclusively on highbush blueberries, a common sight throughout the state. 

“The moth is completely restricted to east of the Connecticut River and only in acidic habitats, specifically on sandy soil,” Keras says. “So, unless it’s in that specific habitat, even if there are blueberries, the moth is not going to be there.”

This dependency on specific host plants makes moths particularly susceptible to environmental change, including global warming. “Very few species are able to adapt to feed on a different plant,” Keras says. “Often, if the host plant is gone, the species is gone as well.”

In addition to his research at Highstead, Keras has conducted lepidopteran surveys for the towns of Ridgefield and Colebrook, and is a member of the Connecticut Entomological Society. He’s particularly interested in rare or declining habitats, such as sandplains and ridgetops, and hopes to become a professional scientist someday.

“My dream is to do something with entomology, examining how this interconnected web works, especially on the level of insects and moths,” he says. “There’s more to know, and that’s what I love about them.”