Over 443 moth species call South Dakota home, yet most residents never notice these nocturnal creatures fluttering through their backyards.
You might be surprised to learn that some of the most spectacular moths in North America thrive right here in the Great Plains, from the enormous cecropia with its six-inch wingspan to the delicate hummingbird clearwing that hovers like its namesake.
Whether you’re drawn to the striking eyespots of the Polyphemus or the fuzzy charm of the Isabella tiger moth, understanding these 25 species will transform your evening walks and give you a new appreciation for South Dakota’s diverse insect life.
1. Luna Moth
The Luna moth (Actias luna) stands out as one of South Dakota’s most enchanting nocturnal visitors. You’ll recognize this pale green beauty by its distinctive long, sweeping tail streamers that extend from each hindwing, creating an elegant silhouette against porch lights on warm summer evenings.
These remarkable moths have wingspans reaching 3 to 4.5 inches, making them impossible to miss when they appear. Their lime-green wings feature delicate eyespots and transparent “windows” near the center. Adult Luna moths live only about one week and never eat during their brief lifespan—they exist solely to reproduce, having no functional mouthparts.
You can spot Luna moths in South Dakota’s deciduous forests and wooded areas from May through July. Their caterpillars feed on the leaves of birch, willow, hickory, and walnut trees, which are common throughout the state. The larvae are bright green with a yellow stripe along each side and small orange spots.
Pro Tip: Luna moths are strongly attracted to ultraviolet light, so you’re most likely to encounter them near outdoor lights during late spring and early summer nights.
2. Polyphemus Moth
The Polyphemus moth (Antheraea polyphemus) earns its name from the giant Cyclops of Greek mythology, thanks to the large eyespots adorning its wings. These tan to reddish-brown moths display prominent eyespots on their hindwings that resemble the face of a great horned owl, serving as an effective defense mechanism against predators.
With wingspans ranging from 4 to 6 inches, Polyphemus moths rank among the largest in South Dakota. You’ll find them in forests, orchards, wetlands, and even urban areas throughout the state. The eyespot pattern not only startles potential predators but also helps divert attacks away from the moth’s vital body parts.
Adult Polyphemus moths have an extremely short lifespan of only about four days. During this brief period, they focus entirely on mating—males use their large, feathery antennae to detect pheromones released by females from up to a mile away. Like Luna moths, adults don’t eat and have no mouth parts.
Their caterpillars are bright green with diagonal white lines and feed on leaves from oak, maple, birch, willow, and various fruit trees. You might notice these plump, lime-colored larvae on trees during summer months before they spin brown cocoons wrapped in leaves.
3. Cecropia Moth
The Cecropia moth (Hyalophora cecropia) holds the title as North America’s largest native moth, with some individuals boasting wingspans up to 6 inches. This brownish-red giant features distinctive crescent-shaped white spots bordered in red on each wing, along with bands of white, red, and tan creating a striking pattern.
You’ll most likely encounter Cecropia moths near deciduous forests and wooded areas across South Dakota from May through early July. Their robust, furry bodies and bold coloration make them unmistakable when they flutter around outdoor lights on warm spring nights.
Female Cecropia moths lay their eggs on a variety of host trees, including maple, birch, willow, apple, and cherry. The caterpillars that emerge are equally impressive—they grow up to 4 inches long and display a blue-green color with rows of yellow and blue tubercles along their backs.
Like other members of the giant silk moth family, adult Cecropias don’t feed and live only about two weeks. Their sole purpose during adulthood centers on reproduction. Males are particularly active fliers, searching for females throughout the night.
4. Io Moth
The Io moth (Automeris io) presents one of the most dramatic examples of sexual dimorphism among South Dakota moths. Male Io moths display bright yellow wings, while females wear rich brownish-purple or reddish-brown wings—yet both sexes share the species’ signature feature: large eyespots on their hindwings.
These eyespots feature black centers surrounded by white and blue rings, creating a startling appearance when the moth suddenly reveals them by opening its wings. This “flash coloration” serves as an effective defense, momentarily confusing predators and giving the moth time to escape.
You can find Io moths throughout South Dakota in various habitats including forests, fields, and suburban areas from May through September. Adults have wingspans of 2 to 3 inches and are frequently drawn to lights at night.
Important Note: While adult Io moths are harmless, their caterpillars pack a painful sting. The bright green larvae are covered with clusters of branching spines that contain venom. These caterpillars feed on a wide variety of trees and shrubs, including willow, maple, oak, and various garden plants. If you spot one, admire it from a distance and never handle it with bare hands.
5. Imperial Moth
The Imperial moth (Eacles imperialis) lives up to its regal name with impressive size and striking coloration. These large moths display yellow wings adorned with variable amounts of purple or brown spots and patches, creating patterns unique to each individual—no two Imperial moths look exactly alike.
With wingspans reaching 3 to 7 inches, Imperial moths rank among South Dakota’s most substantial moth species. Males tend to be smaller and more yellow, while females are larger with more extensive purple markings. Both sexes feature fuzzy bodies and long antennae, with males sporting more feathered antennae for detecting female pheromones.
You’ll encounter Imperial moths in deciduous and mixed forests across South Dakota from June through August. They’re strongly attracted to lights and commonly appear around porch lights and street lamps during summer evenings. Their caterpillars are equally impressive—large, hairy larvae that range in color from dark brown to green, feeding on oak, maple, pine, and sweet gum leaves.
Adult Imperial moths don’t feed and live approximately one to two weeks. Females lay eggs in small clusters on host tree leaves, and the resulting caterpillars will eventually burrow into the soil to pupate, spending the winter underground before emerging as adults the following summer.
6. Promethea Moth
The Promethea moth (Callosamia promethea) showcases another striking example of sexual dimorphism in the moth world. Males are nearly black with lighter borders on their wings, while females display a much brighter reddish-brown or purplish-brown coloration with distinctive tan borders and wavy lines crossing their wings.
Both sexes feature a small eyespot on each forewing and hindwing, though these are more subtle than those found on Polyphemus or Io moths. Adult Promethea moths have wingspans ranging from 3 to 4 inches and belong to the giant silk moth family.
You’ll find Promethea moths in wooded areas throughout South Dakota, particularly where their host plants thrive. They fly from May through August, with males actively flying during daylight hours—unusual behavior for most moths. Females typically remain still, releasing pheromones to attract males.
The caterpillars are distinctive in appearance, featuring a bluish-green body with four prominent red tubercles near the head and a yellow tubercle near the rear. They feed primarily on leaves of spicebush, sassafras, tulip tree, and various members of the cherry family. The cocoons are particularly interesting—they’re wrapped in leaves and attached to branches by a silken thread, remaining suspended throughout winter.
7. White-Lined Sphinx Moth
The white-lined sphinx moth (Hyles lineata) often causes double-takes from people who mistake it for a hummingbird. This medium-sized moth hovers expertly at flowers, using its long proboscis to sip nectar while remaining airborne—a behavior that earns it the common nickname “hummingbird moth.”
You’ll recognize this species by its distinctive coloring: brown forewings with a buff-colored band and pink hindwings with black borders. True to its name, white lines streak across the forewings, creating an attractive pattern. Adults have wingspans of 2.5 to 3.5 inches and are active during both day and dusk hours.
White-lined sphinx moths are common throughout South Dakota from spring through fall, particularly in gardens, fields, and along roadsides where flowering plants grow. They’re especially attracted to petunias, honeysuckle, and other tubular flowers. Unlike many moths, these insects are powerful, fast fliers capable of long-distance migration.
The caterpillars are equally interesting, displaying considerable color variation from green to black, often with yellow or orange spots and a prominent horn at the rear end. They feed on a wide variety of plants including evening primrose, willow weed, and various garden vegetables.
8. Hummingbird Clearwing Moth
The hummingbird clearwing moth (Hemaris thysbe) represents one of nature’s most convincing mimics. With its transparent wings, robust body, and hovering flight pattern, this day-flying moth so closely resembles a hummingbird that even experienced naturalists sometimes do a double-take.
These fascinating moths have wingspans of 1.5 to 2 inches. Their wings lack the scales typical of most moths in the central portions, creating clear “windows” bordered by reddish-brown margins. Their bodies are olive-green to golden-brown with burgundy patches, and they sport a fan-shaped tail that enhances their hummingbird-like appearance.
You can spot hummingbird clearwing moths visiting flowers throughout South Dakota from April through August. They’re particularly active during daylight hours, buzzing from blossom to blossom in gardens, meadows, and forest edges. Their long proboscis allows them to feed on nectar from a variety of flowers, with particular fondness for honeysuckle, bee balm, and phlox.
The caterpillars are yellow-green with darker green lines along the sides and feed primarily on honeysuckle and related plants. They feature the characteristic horn at the rear end typical of sphinx moth larvae. Before pupating, the caterpillars turn burgundy-brown and burrow into leaf litter to form their chrysalises.
9. Snowberry Clearwing Moth
The snowberry clearwing moth (Hemaris diffinis) closely resembles its cousin, the hummingbird clearwing, and shares the same remarkable ability to hover at flowers while feeding. The key difference lies in their coloring—snowberry clearwings have black legs and darker bodies, often appearing almost bumblebee-like with their black and yellow coloration.
These day-flying moths have wingspans ranging from 1.25 to 2 inches. Like the hummingbird clearwing, their wings are mostly transparent with dark borders, though they may appear slightly bluish in certain light. Their bodies are black with yellow bands, creating a striking contrast that helps distinguish them from other sphinx moths.
You’ll encounter snowberry clearwing moths in gardens, meadows, and along woodland edges across South Dakota from May through August. They show strong preferences for certain flowers, including honeysuckle, lilac, verbena, and thistles. Their rapid wing beats produce an audible hum as they hover at flowers.
The larvae feed primarily on snowberry and related plants in the honeysuckle family, which gives the species its common name. The caterpillars are pale green or yellowish with faint lines and spots, featuring the characteristic horn typical of sphinx moth caterpillars.
Key Insight: Both clearwing species are excellent pollinators and beneficial insects in gardens. Their ability to hover and feed during daylight hours makes them particularly effective at pollinating flowers that hummingbirds also visit.
10. Galium Sphinx Moth
The Galium sphinx moth (Hyles gallii), also known as the bedstraw hawkmoth, displays beautiful olive-green and pink coloration that makes it one of South Dakota’s more attractive sphinx moths. Its forewings are olive-brown with darker patches and a pale stripe, while the hindwings feature a pink base color with dark bands.
With wingspans of 2 to 3 inches, these moths are medium-sized members of the sphinx family. They’re powerful fliers capable of sustained hovering while feeding on nectar from tubular flowers. You’ll most often see them at dusk and during the night, though they occasionally fly during daylight hours.
Galium sphinx moths occur throughout South Dakota, particularly in areas where their host plants grow. Adults are active from June through September and are attracted to a variety of flowering plants including honeysuckle, petunia, and phlox. Their long proboscis allows them to access nectar from deep, tubular flowers.
The caterpillars are among the most variable in appearance, ranging from green to brown to nearly black, often with pale spots along their sides. They feed primarily on bedstraw (Galium species), which gives them their common name, but also accept other plants including evening primrose and fireweed.
11. Achemon Sphinx Moth
The Achemon sphinx moth (Eumorpha achemon) stands out among South Dakota’s sphinx moths with its pinkish-brown coloration and unique triangular shape. These moths have a distinctive appearance with their narrow, pointed forewings and small hindwings, creating an almost delta-wing silhouette.
Adults display variable coloring ranging from pink to brown, often with darker bands crossing the wings. They have wingspans of 3.5 to 4 inches and robust, streamlined bodies typical of strong-flying sphinx moths. Their hindwings are brownish with pink or reddish patches near the body.
You’ll find Achemon sphinx moths in vineyards, gardens, and areas with wild grape vines across South Dakota from June through August. Adults are active at dusk and throughout the night, visiting flowers to feed on nectar. They’re particularly attracted to petunias, Japanese honeysuckle, and other fragrant evening flowers.
The caterpillars are especially interesting because they change appearance as they mature. Young larvae are green with a prominent horn at the rear, but older caterpillars lose the horn and develop an eyespot on the side of the body. They feed primarily on grape and Virginia creeper leaves, making them common in both wild and cultivated grape-growing areas.
12. Blinded Sphinx Moth
The blinded sphinx moth (Paonias excaecata) earns its curious name from its eyespots—or rather, the lack thereof. While many sphinx moths display prominent eyespots for defense, this species has reduced eyespots that appear “blind” or incomplete, with the centers being much paler than the surrounding dark rings.
These moths display soft colors ranging from gray to pinkish-brown, with subtle mottling and wavy lines across their wings. Adults have wingspans of 2 to 3 inches and a streamlined body shape characteristic of sphinx moths. The hindwings are rose-pink with grayish borders, creating a beautiful contrast when the wings are spread.
Blinded sphinx moths inhabit wooded areas and suburbs throughout South Dakota, flying from May through August. They’re nocturnal and readily come to lights at night. Unlike some sphinx moths that hover while feeding, blinded sphinx moths typically land on flowers to feed, though they maintain the family’s characteristic long proboscis.
The caterpillars are bright green with seven diagonal white stripes along each side of the body and a distinctive blue-green or pink horn at the rear. They feed on leaves of willow, poplar, birch, and various fruit trees. Before pupating, the caterpillars turn pinkish-brown and burrow into the soil.
13. Small-Eyed Sphinx Moth
The small-eyed sphinx moth (Paonias myops) closely resembles its relative, the blinded sphinx, but features more distinct eyespots on its hindwings. These eyespots are black with blue centers, though they’re still relatively small compared to those of other eyespot-bearing moths like the Io or Polyphemus.
Adults display mottled gray-brown forewings with subtle patterns that provide excellent camouflage when resting on tree bark. Their hindwings are warm brownish-pink with dark borders and the characteristic small eyespots. Wingspans range from 2 to 3.5 inches, making them medium-sized sphinx moths.
You’ll encounter small-eyed sphinx moths in forested areas and suburban neighborhoods across South Dakota from May through August. Like many sphinx moths, they’re nocturnal and attracted to lights. They feed on nectar from various flowers using their long proboscis while hovering or perching.
The caterpillars are bright green with seven pairs of diagonal yellow stripes along the sides and a bluish or pinkish horn at the rear end. They feed on cherry, birch, poplar, willow, and various other deciduous trees. When threatened, the caterpillars may rear up in a defensive posture, making them appear larger and more intimidating.
14. Twin-Spotted Sphinx Moth
The twin-spotted sphinx moth (Smerinthus jamaicensis) gets its name from the distinctive paired blue eyespots on each hindwing. These eyespots are particularly vibrant, with black centers surrounded by bright blue and then edged with black, creating a striking pattern when the moth reveals its hindwings.
The forewings are mottled gray and brown, providing excellent camouflage against tree bark when the moth rests during the day. Adults have wingspans of 2 to 3 inches and the typical robust, streamlined body shape of sphinx moths. When disturbed, they flash their hindwings to display the eyespots, which can startle potential predators.
Twin-spotted sphinx moths are found in wooded areas, parks, and suburban neighborhoods throughout South Dakota from May through August. They’re nocturnal and commonly appear at porch lights and street lamps. Interestingly, adult twin-spotted sphinx moths have reduced mouthparts and feed little or not at all, relying on energy stored from their caterpillar stage.
The caterpillars are pale green with white granules giving them a rough texture, and they feature seven diagonal white or pale yellow lines along each side of the body. A blue-green or pinkish horn adorns the rear end. These larvae feed on leaves of willow, poplar, birch, apple, and various other trees and shrubs.
15. Tomato Hornworm Moth
The tomato hornworm moth (Manduca quinquemaculata), also called the five-spotted hawkmoth, might be South Dakota’s most notorious moth among gardeners. While the adult moths are impressive and beneficial pollinators, their caterpillars—the infamous tomato hornworms—can devastate garden tomato plants overnight.
Adult moths are large and robust, with wingspans reaching 4 to 5 inches. They display mottled gray-brown wings with zigzag patterns and five pairs of orange-yellow spots along each side of the abdomen, which gives them their alternative name. These powerful fliers excel at hovering while feeding on nectar from deep, tubular flowers.
You’ll find these moths throughout South Dakota from late spring through early fall, particularly near vegetable gardens and areas where nightshade family plants grow. Adults are most active at dusk and during nighttime hours, visiting flowers like petunias, moonflowers, and jimsonweed.
The caterpillars are what make this species so well-known to gardeners. These large, green larvae can reach 4 inches in length and feature seven diagonal white stripes along their sides and a distinctive black horn at the rear. They feed voraciously on tomato, tobacco, pepper, and eggplant leaves. While they can cause significant damage, many gardeners appreciate the adult moths as pollinators and choose to hand-pick the caterpillars to relocate them rather than using pesticides.
16. Tobacco Hornworm Moth
The tobacco hornworm moth (Manduca sexta) is nearly identical to the tomato hornworm moth, and even experienced naturalists sometimes struggle to distinguish them. The key difference lies in the abdominal markings—tobacco hornworm moths have six pairs of orange-yellow spots along their abdomen, while tomato hornworm moths have five pairs.
These large moths share the same impressive wingspan of 4 to 5 inches and similar gray-brown mottled wing patterns. Their bodies are robust and streamlined for powerful, sustained flight. Like their close relatives, tobacco hornworm moths are excellent hovering fliers and important nighttime pollinators.
Tobacco hornworm moths occur throughout South Dakota in areas where solanaceous plants grow, including gardens, fields, and wild areas. Adults fly from late spring through early fall and are most active during twilight and nighttime hours. They visit many of the same flowers as tomato hornworm moths and play important roles as pollinators.
The caterpillars are the easiest way to distinguish between the two species. Tobacco hornworms have diagonal white stripes like their cousins, but they sport a red horn at the rear end instead of a black one. They feed on tobacco, tomato, and other members of the nightshade family. Despite being garden pests, these caterpillars serve as important food sources for parasitic wasps and other beneficial insects.
Common Mistake: Many people kill all hornworm caterpillars on sight, but if you find one covered with small white cocoons, leave it alone. Those cocoons belong to beneficial parasitic wasps that help control hornworm populations naturally.
17. Cabbage Looper Moth
The cabbage looper moth (Trichoplusia ni) might seem unremarkable at first glance, but its caterpillars are among the most recognizable garden pests in South Dakota. These small moths have mottled brown and gray wings with a distinctive silvery or white figure-eight marking near the center of each forewing.
Adults have wingspans of about 1.5 inches and relatively thin bodies compared to robust sphinx moths. Their wings are held in a characteristic tent-like position when at rest. You’ll notice their slightly metallic or iridescent sheen when light catches their wings at certain angles.
Cabbage looper moths are common throughout South Dakota from spring through fall, with multiple generations per year in warmer months. Adults are nocturnal and attracted to lights, though they’re not as conspicuous as larger moth species. They visit flowers to feed on nectar, showing particular interest in sweet-scented blooms.
The caterpillars earn the “looper” name from their distinctive movement—they lack middle prolegs, so they arch their bodies into loops as they crawl, similar to inchworms. These pale green larvae with white stripes feed on cabbage, broccoli, cauliflower, and related crops, as well as many garden flowers. While they can cause damage to vegetables, their presence also attracts beneficial predators and parasites to gardens.
18. Yellow Underwing Moth
The yellow underwing moth (Noctua pronuba) presents one of the most dramatic examples of flash coloration among South Dakota moths. When at rest, these moths display drab brown forewings that blend perfectly with bark and leaf litter. But when disturbed or in flight, they suddenly reveal brilliant orange-yellow hindwings with a black border—a shocking transformation that startles predators.
Adults have wingspans of 2 to 2.5 inches and show considerable variation in forewing color, ranging from light brown to nearly black. Some individuals display subtle markings or mottling on the forewings, while others appear relatively plain. The hindwings remain consistently bright yellow-orange with distinctive black bands.
Originally from Europe, yellow underwing moths have become well-established across South Dakota. You’ll encounter them from June through October, with peak activity in late summer and early fall. Adults are nocturnal and strongly attracted to lights, making them common visitors to porch lights and lit windows.
The caterpillars are equally variable in appearance, ranging from green to brown with darker mottling. They’re generalist feeders consuming a wide variety of low-growing plants, including grasses, clover, and many garden vegetables. While they can occasionally reach pest status in lawns and gardens, populations typically remain at manageable levels in South Dakota.
19. Fall Armyworm Moth
The fall armyworm moth (Spodoptera frugiperda) gets its dramatic name from the behavior of its caterpillars, which can march across fields in large groups like an army, consuming vegetation as they go. Adults are relatively nondescript moths with mottled gray-brown forewings marked with lighter and darker patches.
These moths have wingspans of about 1.5 inches. Males typically display more distinct wing patterns than females, with noticeable light and dark areas creating a mottled appearance. The hindwings are silvery-white with dark borders, visible only when the moth is in flight or has its wings spread.
Fall armyworm moths don’t overwinter in South Dakota—they migrate north from southern states each year, typically arriving in late spring or early summer. You’ll find them in agricultural areas, pastures, and lawns throughout the growing season. Adults are nocturnal and attracted to lights, though they’re most notable for the damage their caterpillars can cause.
The caterpillars are smooth with variable coloring ranging from green to brown to nearly black. They feature a distinctive inverted Y-shaped marking on the front of the head and three light-colored lines running lengthwise down the back. These larvae feed on grasses, corn, and many other crops and can cause significant agricultural damage when populations are high. However, in South Dakota, they’re more often found in small numbers as late-season pests.
20. Giant Leopard Moth
The giant leopard moth (Hypercompe scribonia) ranks among South Dakota’s most strikingly patterned moths. Adults display pristine white wings covered with black and blue-ringed spots, creating a leopard-like pattern that’s unmistakable. This bold coloration serves as a warning to predators that the moths are unpalatable.
With wingspans reaching 3 to 3.5 inches, these are substantial moths that command attention. Their bodies are equally dramatic—bright metallic blue with orange bands. When threatened, giant leopard moths will pull their legs up and display their colorful abdomens, reinforcing their warning signals to potential predators.
You’ll encounter giant leopard moths throughout South Dakota from April through September, though they’re most common in mid to late summer. They frequent gardens, meadows, and woodland edges, and adults are strongly attracted to lights at night. Unlike many moth species that rest with wings folded, giant leopard moths often hold their wings partially spread, displaying their beautiful patterns.
The caterpillars are just as remarkable as the adults. Known as “woolly bears,” these larvae are covered with stiff black bristles and red bands between their body segments. They’re general feeders that consume a wide variety of plants including plantain, dandelion, violets, and various garden plants. The caterpillars overwinter and are sometimes seen actively crawling on warm winter days.
21. Banded Tussock Moth
The banded tussock moth (Halysidota tessellaris) displays subtle beauty with its pale yellow to cream-colored wings decorated with delicate dark spots and wavy bands. Adults have a soft, furry appearance due to the hair-like scales covering their bodies and wings, giving them an almost fuzzy texture.
These moths have wingspans of 1.5 to 2 inches and maintain the typical moth posture of wings held roof-like over the body when at rest. Their coloring can vary from nearly white to golden-yellow, with the darker markings ranging from faint to quite distinct depending on the individual.
Banded tussock moths occur in deciduous forests and wooded areas throughout South Dakota from May through August. Adults are nocturnal and attracted to lights, though they’re not as commonly encountered as some larger, more conspicuous species. They feed on nectar from various flowers when adult.
The caterpillars are where this species really stands out. The larvae feature tufts of white, yellow, or cream-colored bristles along their backs, with longer black tufts at the head and rear. Four prominent white tufts stick up like flags along the center of the back. These hairy caterpillars feed on leaves of various deciduous trees including oak, willow, birch, and maple. While the bristles may look threatening, they’re generally not irritating to most people, though it’s still wise to avoid handling them.
22. Virgin Tiger Moth
The virgin tiger moth (Grammia virgo), also known as Grammia virgo, showcases the bold patterns typical of tiger moths. Adults display black forewings decorated with cream-colored or white spots and bands, while the hindwings are pink or red with black borders and spots—a classic warning coloration pattern.
These striking moths have wingspans of 1.5 to 2.5 inches and robust, hairy bodies marked with black and white or yellow. When at rest, they fold their wings tent-like over their bodies, concealing the colorful hindwings. But when threatened or in flight, the sudden flash of pink or red underwings serves as a warning to predators.
You’ll find virgin tiger moths in meadows, prairies, and open woodland areas throughout South Dakota from June through August. Adults are nocturnal and readily come to lights. Like many tiger moths, they’re chemically defended—toxins accumulated from their larval diet make them distasteful to predators.
The caterpillars are covered with dense hair tufts ranging from black to reddish-brown. These “woolly bear” type larvae feed on a variety of low-growing plants including plantain, clover, and various wildflowers. They’re general feeders that rarely cause significant plant damage and serve as food for specialized predators that can tolerate their defensive chemicals.
23. Salt Marsh Moth
The salt marsh moth (Estigmene acrea) might seem misnamed for South Dakota, as true salt marshes are scarce in the state. However, this adaptable moth thrives in various habitats including meadows, fields, gardens, and agricultural areas throughout the region.
Adults are medium-sized with wingspans of 1.5 to 2.5 inches. They display considerable variation in appearance—some individuals are nearly pure white, while others show extensive black or brown spots on their wings. Males typically have more spots than females. The abdomen is yellow-orange with rows of black spots, creating a distinctive pattern visible when the wings are spread.
Salt marsh moths are common throughout South Dakota from May through September, with multiple generations possible in warmer years. Adults are nocturnal and attracted to lights. They’re strong fliers capable of covering considerable distances, which contributes to their widespread distribution.
The caterpillars are densely covered with long, stiff hairs ranging from yellow to brown or black. These “woolly bear” larvae are generalist feeders that consume a wide variety of plants including vegetables, flowers, and weeds. While they occasionally reach pest status in agricultural settings, they’re more often encountered in small numbers. The larvae can cause mild skin irritation in sensitive individuals, so it’s best to observe them without touching.
24. Isabella Tiger Moth
The Isabella tiger moth (Pyrrharctia isabella) holds a special place in American folklore thanks to its caterpillar stage—the famous “woolly bear” that supposedly predicts winter severity. While this weather prediction is scientifically unfounded, these moths remain among South Dakota’s most beloved and recognized insects.
Adults are understated compared to many tiger moths, displaying orange-yellow to yellowish-brown wings with sparse black spotting. Their coloring ranges from bright orange to pale tan, and females typically have brighter, more orange-tinted hindwings than males. Wingspans range from 1.75 to 2.5 inches, and their bodies are orange with black spots.
Isabella tiger moths fly in South Dakota from May through September, though you’re more likely to encounter their caterpillars than the adult moths. Adults are nocturnal and attracted to lights but aren’t particularly common at porch lights compared to some other species.
The caterpillars are what make this species famous. These fuzzy larvae sport distinctive bands of black and reddish-brown bristles, with the width of the bands varying among individuals. Contrary to folklore, band width relates to the caterpillar’s age and diet, not to coming weather. These hardy caterpillars can survive being frozen solid during winter by producing a cryoprotectant in their tissues. They feed on a wide variety of low-growing plants and are often seen crossing roads and sidewalks in fall as they search for protected spots to spend winter.
25. Gypsy Moth (Spongy Moth)
The gypsy moth (Lymantria dispar), now also called the spongy moth, represents a significant invasive species concern in South Dakota. Originally introduced to Massachusetts in 1869, these moths have gradually spread westward and now pose threats to forests throughout the state.
Male and female gypsy moths look dramatically different. Males are brown with feathery antennae and wingspans of about 1.5 inches—they’re active fliers that search for females during the day. Females are much larger with wingspans up to 2.5 inches, displaying white to cream-colored wings with dark wavy markings. Despite their large wings, females rarely fly, instead remaining on tree trunks where they emerged and releasing pheromones to attract males.
Gypsy moths typically fly in South Dakota from June through August. While adults don’t feed or cause direct damage, the species poses serious concerns because of its caterpillars’ voracious appetites and their preference for oak trees—a valuable component of South Dakota’s forests and urban landscapes.
The caterpillars are easily identified by their hairy appearance and distinctive markings: five pairs of blue spots followed by six pairs of red spots along the back. These larvae are generalist feeders but show strong preferences for oak, aspen, and willow. During outbreak years, they can completely defoliate large areas of forest. South Dakota actively monitors for gypsy moth populations and implements control measures when necessary to protect forests and urban trees. If you suspect you’ve found gypsy moth egg masses (tan, fuzzy clusters on tree bark) or caterpillars, report them to your local extension office.
South Dakota’s moth diversity offers endless opportunities for discovery and observation. From the spectacular giant silk moths to the humble woolly bears crossing autumn roads, these 25 species represent just a fraction of the moths calling this state home.
Whether you’re setting up a moth sheet and light to attract nocturnal visitors or simply paying closer attention to the insects around your porch light, you’ll find that moths are far more varied, beautiful, and ecologically important than most people realize.
As you become familiar with these species, you’ll develop a deeper appreciation for the complex web of life that exists right in your own backyard—and you might just inspire others to look more closely at these often-overlooked nighttime neighbors.
