South Dakota’s diverse landscapes, from the Black Hills to the prairie grasslands, provide habitat for an impressive variety of caterpillars throughout the growing season. Whether you’re exploring your backyard garden or hiking through state parks, you’re likely to encounter these fascinating larvae that will eventually transform into beautiful butterflies and moths.
Understanding which caterpillars call South Dakota home can enhance your outdoor experiences and help you appreciate the intricate web of nature surrounding you.
From the iconic orange and black Monarch caterpillars feeding on milkweed to the fuzzy Woolly Bear caterpillars crossing sidewalks in fall, each species has unique characteristics, preferred host plants, and seasonal patterns.
This comprehensive guide covers the 20 most commonly encountered caterpillars in South Dakota, providing you with the knowledge to identify them confidently and understand their role in the local ecosystem.
1. Cabbage White Caterpillar
The Cabbage White caterpillar (Pieris rapae) is one of the most common garden visitors you’ll encounter in South Dakota. These pale green caterpillars with a velvety texture measure about 1 inch long when fully grown and feature a faint yellow stripe running down their backs. You’ll typically find them munching on plants in the Brassicaceae family, including cabbage, broccoli, cauliflower, and mustard greens.
These caterpillars can produce multiple generations per year in South Dakota’s climate, with peak activity occurring from late spring through early fall. While they’re considered agricultural pests due to their appetite for crop plants, they also feed on wild mustards and other native plants. The adult Cabbage White butterflies are small, white insects with black spots that you’ll see fluttering around gardens throughout the growing season.
Pro Tip: If you’re growing brassicas in your garden, check the undersides of leaves regularly for small, yellowish eggs that will hatch into these caterpillars within a week.
2. Woolly Bear Caterpillar
The beloved Woolly Bear caterpillar (Pyrrharctia isabella) is perhaps South Dakota’s most recognizable caterpillar, with its distinctive bands of black and reddish-brown bristles. These fuzzy caterpillars grow to about 2 inches long and are most commonly spotted in late summer and fall as they search for overwintering sites. Contrary to popular folklore, the width of their color bands doesn’t predict winter weather severity.
You’ll find Woolly Bears feeding on a wide variety of plants, including dandelions, plantain, clover, and various grasses. They’re particularly active during warm autumn days, often crossing roads and sidewalks as they seek protected areas to spend the winter. These hardy caterpillars can survive South Dakota’s harsh winters by producing glycerol, a natural antifreeze that prevents ice crystal formation in their bodies.
The transformation process is remarkable – after overwintering, they pupate in spring and emerge as Isabella Tiger Moths, cream-colored moths with black spots and orange hindwings. For more information about caterpillars with similar characteristics, you can explore other caterpillar varieties found across different regions.
3. Yellow Woolly Bear Caterpillar
The Yellow Woolly Bear caterpillar (Spilosoma virginica) stands out with its pale yellow to cream-colored fuzzy appearance. These caterpillars measure approximately 1.5 to 2 inches long and are covered in dense, soft bristles that give them their characteristic woolly appearance. Unlike their more famous cousins, Yellow Woolly Bears maintain a consistent coloration throughout their development.
These generalist feeders consume a broad range of plants, from garden vegetables and flowers to weeds and native prairie plants. You’ll often encounter them in late summer crawling across driveways and sidewalks as they search for pupation sites. Their ability to feed on numerous plant species makes them well-adapted to South Dakota’s diverse habitats, from urban gardens to rural farmlands.
The adult moths, known as Virginian Tiger Moths, are pure white with small black spots scattered across their wings. These moths are active at night and are often attracted to porch lights and other artificial light sources during summer evenings.
4. Forest Tent Caterpillar
Forest Tent caterpillars (Malacosoma disstria) are social insects that create silk mats rather than enclosed tents, despite their common name. These blue-gray caterpillars with white diamond-shaped spots along their backs can reach 2 inches in length. They’re distinguished by their keyhole-shaped markings and the absence of the tent structures created by their Eastern Tent caterpillar relatives.
In South Dakota, Forest Tent caterpillars primarily feed on deciduous trees, with aspen, oak, and maple being their preferred hosts. During outbreak years, which occur cyclically every 10-15 years, these caterpillars can completely defoliate large areas of forest. While this appears devastating, healthy trees typically recover by producing new leaves later in the season.
Important Note: During population outbreaks, Forest Tent caterpillars may wander in large numbers, sometimes covering roads and buildings. They’re harmless to humans but can be a temporary nuisance.
The caterpillars pupate in cocoons attached to tree bark or other surfaces, eventually emerging as tan-colored moths with two dark bands across their forewings. Understanding these natural population cycles helps landowners manage expectations during outbreak years. You can learn more about regional caterpillar patterns by exploring caterpillars in neighboring Colorado.
5. Eastern Tent Caterpillar
Eastern Tent caterpillars (Malacosoma americanum) are the true tent-makers, constructing silken shelters in the crotches of tree branches where they gather during cool weather and at night. These caterpillars are black with blue and white stripes, plus a distinctive white stripe down their backs. They can grow up to 2.5 inches long and are most active during spring months.
Wild cherry trees are their preferred host, though they’ll also feed on apple, crabapple, and other members of the rose family. The conspicuous silk tents make them easy to spot in early spring when leaves are still emerging. Unlike Forest Tent caterpillars, Eastern Tent caterpillars return to their communal tents regularly, expanding them as the colony grows.
These caterpillars complete their development by early summer, spinning cocoons in protected locations before emerging as reddish-brown moths with white bands. The moths mate and lay egg masses that encircle small branches, where they’ll remain until hatching the following spring.
6. White-lined Sphinx Caterpillar
The White-lined Sphinx caterpillar (Hyles lineata) is a impressive larva that can reach 3.5 inches in length. These caterpillars display remarkable color variation, ranging from bright green to black, often with yellow or orange spots and a prominent horn at their rear end. The horn, while intimidating in appearance, is completely harmless and serves as a defensive mechanism to deter predators.
You’ll find these caterpillars feeding on a diverse array of plants, including evening primrose, four o’clock, grape vines, and various garden plants. They’re particularly active during late summer and can sometimes be found crossing roads as they search for pupation sites. Their large size and distinctive appearance make them one of the most memorable caterpillars you might encounter.
The adult White-lined Sphinx moths are often mistaken for hummingbirds due to their hovering flight pattern and day-flying behavior. These moths have a wingspan of 2.5 to 3.5 inches and are important pollinators of many native plants. For comparison with similar species, you might find it interesting to explore caterpillars found in California, where this species is also common.
7. Hummingbird Clearwing Caterpillar
The Hummingbird Clearwing caterpillar (Hemaris thysbe) is another sphinx moth larva that grows to about 2 inches long. These pale green caterpillars have a granulated texture and sport the characteristic horn typical of sphinx moth caterpillars. They feed primarily on honeysuckle, dogbane, and related plants, making them common in woodland edges and gardens where these plants grow.
What makes these caterpillars particularly interesting is their transformation into day-flying moths that closely resemble hummingbirds. The adult moths have clear wings bordered with reddish-brown and hover at flowers while feeding, creating a convincing hummingbird mimic. This mimicry provides protection from predators that might avoid the larger, more aggressive hummingbirds.
These caterpillars typically produce two generations per year in South Dakota, with the second generation overwintering as pupae in the soil. The adult moths are active during daylight hours and are important pollinators of native wildflowers.
8. Polyphemus Moth Caterpillar
The Polyphemus Moth caterpillar (Antheraea polyphemus) is one of South Dakota’s largest caterpillars, reaching up to 4 inches in length. These impressive lime-green caterpillars are adorned with silver spots and small orange tubercles, creating a jewel-like appearance. They feed on a wide variety of deciduous trees, including oak, maple, birch, and willow.
During their development, Polyphemus caterpillars go through five instars, growing dramatically with each molt. In their final instar, they become quite plump and can consume entire leaves rapidly. Despite their large size, they’re often overlooked due to their excellent camouflage among green foliage.
These caterpillars spin large, brown cocoons that are often found attached to branches or fallen leaves. The adult Polyphemus moths are among North America’s largest native moths, with wingspans reaching 6 inches. The moths display prominent eyespots on their hindwings, which give the species its name after the one-eyed giant from Greek mythology.
Key Insight: Polyphemus caterpillars are excellent indicators of forest health, as they require diverse, mature tree communities to complete their life cycle successfully.
9. Monarch Caterpillar
The Monarch caterpillar (Danaus plexippus) is instantly recognizable with its bold black, white, and yellow striped pattern. These caterpillars grow to about 2 inches long and feed exclusively on milkweed plants, which provide them with toxic compounds that make both the caterpillars and adult butterflies unpalatable to predators.
In South Dakota, you’ll find Monarch caterpillars on various milkweed species throughout the summer months. The state serves as crucial breeding habitat for the eastern Monarch population, which undertakes an incredible multi-generational migration to Mexico each fall. The caterpillars you observe in South Dakota may be part of the generation that completes the journey south.
Each caterpillar goes through five instars, shedding its skin four times as it grows. The transformation from caterpillar to butterfly takes about 10-14 days once pupation begins in the distinctive jade-green chrysalis with gold spots. Supporting Monarch populations by planting native milkweeds is one of the most impactful conservation actions you can take in your own backyard. Learn more about other wildlife in South Dakota that shares habitat with Monarchs.
10. Black Swallowtail Caterpillar
Black Swallowtail caterpillars (Papilio polyxenes) undergo dramatic color changes as they mature. Young caterpillars are black with white patches and spines, resembling bird droppings as a protective adaptation. As they grow, they develop green bodies with black bands decorated with yellow or orange spots, creating one of the most beautiful caterpillar patterns in South Dakota.
These caterpillars feed on plants in the carrot family, including dill, parsley, fennel, and wild carrot (Queen Anne’s lace). Garden herbs are particularly attractive to them, making them common visitors to herb gardens throughout the state. When threatened, they can evert a bright orange, forked structure called an osmeterium from behind their head, which releases a strong odor to deter predators.
The adult Black Swallowtail butterflies are large, beautiful insects with black wings decorated with blue and yellow markings. Females have more blue coloration, while males display more prominent yellow spots. These butterflies are important pollinators and add significant beauty to South Dakota’s natural areas and gardens.
11. Tiger Swallowtail Caterpillar
Tiger Swallowtail caterpillars (Papilio glaucus) are masters of disguise, changing their appearance dramatically as they mature. Young caterpillars mimic bird droppings with their brown and white coloration, while mature caterpillars are smooth, green, and plump with large yellow and black eyespots that make them appear snake-like when threatened.
These caterpillars feed on a variety of deciduous trees, with wild cherry, tulip tree, and ash being preferred hosts. In South Dakota, they’re commonly found on cottonwoods and willows near water sources. The caterpillars create silk girdles to help them maintain their position on branches while feeding and resting.
Adult Tiger Swallowtails are among the largest butterflies in North America, with wingspans reaching 5.5 inches. The bright yellow wings with black tiger stripes make them unmistakable as they soar through woodland areas and along river corridors. These butterflies are important pollinators of native wildflowers and garden plants.
12. Painted Lady Caterpillar
Painted Lady caterpillars (Vanessa cardui) are spiny, grayish caterpillars with yellow stripes and branched spines covering their bodies. They typically measure 1.5 inches when fully grown and are often found feeding on thistles, nettles, and various garden plants. These caterpillars create silk shelters by webbing leaves together, providing protection while they feed.
Painted Ladies are remarkable for their global distribution and migratory behavior. In South Dakota, you might encounter caterpillars from resident populations or from migrants arriving from the south during spring and summer. The species can produce multiple generations per year when conditions are favorable, leading to periodic population booms.
The adult Painted Lady butterflies are medium-sized with orange wings decorated with black and white markings. They’re excellent pollinators and are often seen visiting flowers in gardens, prairies, and disturbed areas. Their adaptability to various host plants and habitats makes them one of the most successful butterfly species worldwide. You can compare their distribution patterns with caterpillars found in Texas, where Painted Ladies also thrive.
13. Red Admiral Caterpillar
Red Admiral caterpillars (Vanessa atalanta) are dark-colored with branched spines and feed almost exclusively on nettles. These solitary caterpillars create silk shelters by folding nettle leaves around themselves, providing both food and protection. They measure about 1.5 inches when mature and have a somewhat flattened appearance compared to other caterpillars.
In South Dakota, you’ll find these caterpillars in areas where stinging nettles grow, typically in moist, partially shaded locations such as woodland edges, stream banks, and disturbed soils. The caterpillars’ dependence on nettles makes their distribution closely tied to their host plant’s availability.
Adult Red Admiral butterflies are striking insects with dark wings marked by red bands and white spots. They’re strong migrants and can travel considerable distances, with northern populations often supplemented by southern migrants each year. These butterflies are commonly seen in gardens, where they feed on tree sap, rotting fruit, and occasionally flower nectar.
Common Mistake: Don’t confuse Red Admiral caterpillars with other spiny caterpillars – their exclusive use of nettles as host plants is a key identifying characteristic.
14. Mourning Cloak Caterpillar
Mourning Cloak caterpillars (Nymphalis antiopa) are gregarious feeders that often occur in groups on willow, elm, and poplar trees. These spiny black caterpillars with white spots and red markings can grow to 2 inches long and are capable of defoliating entire branches when present in large numbers. Their group feeding behavior provides protection through intimidation and shared vigilance.
These caterpillars are most commonly encountered in late spring and early summer, often near water sources where their preferred host trees grow. In South Dakota, you’ll find them along rivers, streams, and in riparian woodlands. The caterpillars pupate in groups, hanging from branches or other structures in brownish chrysalides.
Adult Mourning Cloak butterflies are among the longest-lived butterflies, with individuals capable of surviving nearly a year. They overwinter as adults, often hiding under loose bark or in tree cavities. These dark purple-brown butterflies with yellow borders are among the first to appear in spring, sometimes flying on warm days even when snow is still present. For additional information about South Dakota’s diverse wildlife, explore other animals in the region.
15. Cecropia Moth Caterpillar
The Cecropia Moth caterpillar (Hyalophora cecropia) is North America’s largest native moth caterpillar, reaching lengths of 4-5 inches. These magnificent caterpillars are blue-green with red, orange, and yellow tubercles arranged in rows along their bodies. They feed on a variety of deciduous trees, including maple, cherry, birch, and elderberry.
Cecropia caterpillars grow slowly, taking most of the summer to complete their development. They’re most commonly found in late summer when they’re at their largest and most conspicuous. Despite their impressive size, they’re often overlooked due to their excellent camouflage among foliage.
The adult Cecropia moths are equally impressive, with wingspans reaching 7 inches. These moths don’t feed as adults and live only long enough to mate and lay eggs. The large, brown cocoons are often found attached to branches and are sometimes collected for educational purposes. Conservation of mature forests and diverse tree communities is essential for maintaining healthy Cecropia populations.
16. Io Moth Caterpillar
Io Moth caterpillars (Automeris io) are among the few caterpillars in South Dakota that can deliver a painful sting. These pale green caterpillars are covered in branched spines that contain irritating compounds. When fully grown, they measure about 2.5 inches long and feed on a wide variety of plants, including corn, roses, willows, and various garden plants.
The stinging spines serve as an effective defense mechanism against predators and can cause skin irritation in humans similar to stinging nettle. If you encounter one of these caterpillars, observe from a distance and avoid direct contact. Despite their defensive capabilities, they’re important components of the ecosystem and eventually transform into beautiful moths.
Adult Io moths display dramatic sexual dimorphism, with males being bright yellow and females being reddish-brown. Both sexes feature prominent eyespots on their hindwings, which give the species its name after the Greek mythological figure Io. The moths are active at night and are often attracted to artificial lights.
17. Giant Leopard Moth Caterpillar
Giant Leopard Moth caterpillars (Hypercompe scribonia) are distinctive black caterpillars covered in stiff black bristles with red bands visible between their segments. These caterpillars can curl into a tight ball when threatened, exposing the bright red warning coloration. They grow to about 3 inches long and feed on a wide variety of plants, from garden vegetables to native wildflowers.
These caterpillars are most active in late summer and fall, often seen crossing sidewalks and roads as they search for overwintering sites. They’re capable of surviving South Dakota’s cold winters by entering diapause and can withstand freezing temperatures. Their broad diet and cold tolerance make them well-adapted to the state’s climate and plant communities.
The adult Giant Leopard moths are striking white insects with black spots scattered across their wings and body, resembling their namesake pattern. These large moths have wingspans of 3-4 inches and are occasionally attracted to porch lights during summer evenings. You can find similar caterpillar species by exploring caterpillars in South Carolina, where Giant Leopard moths are also present.
18. Buckeye Caterpillar
Buckeye caterpillars (Junonia coenia) are dark-colored with orange markings and prominent spines, particularly noticeable on their heads and bodies. These caterpillars feed primarily on plantain, snapdragon, and other plants in the figwort family. They’re typically solitary feeders and can be found in open areas, gardens, and disturbed habitats throughout South Dakota.
The caterpillars are most commonly encountered in late summer, as Buckeye butterflies often migrate northward during the growing season. These migrants may establish temporary breeding populations in South Dakota, though the species cannot survive the state’s winters and must recolonize each year from southern populations.
Adult Buckeye butterflies are medium-sized with brown wings featuring prominent eyespots that give them their common name. These butterflies are strong fliers and are often seen in open areas, flying low over vegetation as they search for nectar sources and egg-laying sites. Their migratory behavior makes them an exciting species to encounter during the appropriate seasons.
19. Viceroy Caterpillar
Viceroy caterpillars (Limenitis archippus) are mottled brown and green with a distinctive hump behind their head, making them excellent mimics of bird droppings when small.
As they mature, they develop a more intricate pattern that helps them blend with bark and lichen. These caterpillars feed exclusively on willows and poplars, making them common near water sources throughout South Dakota.
The caterpillars create hibernacula (winter shelters) by rolling leaves and securing them with silk. They overwinter in these shelters as partially grown caterpillars, resuming feeding and development in spring. This adaptation allows them to take advantage of the brief growing season while surviving harsh winter conditions.
Adult Viceroy butterflies are famous mimics of Monarch butterflies, though they’re smaller and have a black line across their hindwings. This mimicry provides protection from predators that have learned to avoid the toxic Monarchs.
Viceroys are common along rivers, streams, and wetland edges where their host plants thrive. To learn more about regional wildlife patterns, you can explore other South Dakota animals.
20. Checkered White Caterpillar
Checkered White caterpillars (Pontia protodice) are small, green caterpillars with yellow stripes and fine hairs covering their bodies. They feed on plants in the mustard family, including wild mustards, peppergrass, and occasionally garden crops like cabbage and broccoli. These caterpillars are typically found in open areas, prairies, and disturbed habitats where their host plants are abundant.
Checkered Whites can produce multiple generations per year in South Dakota’s climate, with caterpillars present from spring through fall. The species is well-adapted to the state’s prairie environment and can be quite common in areas with suitable host plants. Their small size and cryptic coloration often make them difficult to notice unless you’re specifically looking for them.
The adult Checkered White butterflies are small, white butterflies with black checkered patterns on their wings, particularly prominent in males. These butterflies are active fliers and are often seen in prairie areas, gardens, and along roadsides where mustard family plants grow. They’re important pollinators of native wildflowers and contribute to the biodiversity of South Dakota’s grassland ecosystems.
Pro Tip: The best time to search for caterpillars in South Dakota is during late morning hours on warm, sunny days when they’re most active and visible on their host plants.
Understanding and appreciating South Dakota’s caterpillar diversity enhances your connection to the natural world around you. Each species plays a vital role in local ecosystems, from pollination services provided by adult butterflies and moths to serving as food sources for birds, spiders, and other wildlife.
By learning to identify these fascinating creatures, you become a better steward of South Dakota’s rich biodiversity and can contribute to conservation efforts that protect these important insects and their habitats for future generations to discover and enjoy.
