When you step into your Indiana backyard, you’re entering a world filled with remarkable transformations happening right before your eyes.
Did you know that Indiana hosts over 156 documented caterpillar species, with 24 of them being so common you’ll likely encounter them in your own yard? These fascinating larvae aren’t just garden visitors—they’re future butterflies and moths that play crucial roles as pollinators, food sources for birds, and indicators of a healthy ecosystem.
Whether you’ve spotted a striped monarch munching on milkweed or discovered a fuzzy woolly bear crossing your sidewalk, this guide will help you identify each species and understand what makes them special.
From the toxic warning colors of some species to the incredible camouflage of others, you’ll discover why these crawling creatures deserve your attention and respect.
1. Monarch Caterpillar
The Monarch caterpillar (Danaus plexippus) stands as Indiana’s most recognizable and beloved larva. These distinctive creatures sport bold black, white, and yellow stripes running lengthwise down their bodies, complemented by two pairs of black tentacles—one pair near the head and another near the rear.
Pro Tip: The bright warning colors aren’t just for show. Monarchs are genuinely toxic to predators thanks to the milkweed toxins they accumulate while feeding.
You’ll find these iconic caterpillars exclusively on milkweed plants throughout Indiana from late spring through early fall. The entire lifecycle of the monarch butterfly is dependent on the milkweed, as it is the only plant the monarch larvae can eat. By the time it is done growing, the caterpillar will weigh about 2,700 times more than when it hatched.
Look for them in prairies, roadsides, gardens, and anywhere common milkweed, swamp milkweed, or butterfly weed grows. The female butterflies lay single eggs on the undersides of milkweed leaves, providing protection from sun and rain.
2. Black Swallowtail Caterpillar
The Black Swallowtail caterpillar (Papilio polyxenes) transforms dramatically as it grows. Young larvae start as small, dark caterpillars with a white saddle marking, while mature specimens develop striking bands of black, yellow, and green with bright orange spots.
These versatile feeders target plants in the carrot family, making them common visitors to herb gardens. You’ll discover them on parsley, dill, fennel, carrots, and Queen Anne’s lace throughout Indiana’s growing season.
Key Insight: When threatened, Black Swallowtail caterpillars extend orange, horn-like projections called osmeteria from behind their heads, releasing a strong odor to deter predators.
The distinctive appearance and defensive behavior make these caterpillars relatively easy to identify. They prefer sunny locations where their host plants thrive, including gardens, fields, and roadside areas.
3. Tiger Swallowtail Caterpillar
Eastern Tiger Swallowtail caterpillars (Papilio glaucus) are masters of disguise. In their early stages, eastern tiger swallowtail caterpillars sport a brown and white color scheme, which evolves as they age. As they reach maturity, these caterpillars transform into a vivid green color decorated with orange and black false eyespots.
These remarkable eyespots serve as brilliant defense mechanisms, making the caterpillar appear like a small snake to potential predators. The transformation from bird-dropping mimic to snake impersonator showcases nature’s incredible adaptability.
The diet of eastern tiger swallowtail larvae includes leaves from a variety of trees, such as wild cherry, tulip, and birch. You’ll also find them feeding on ash, basswood, and cottonwood trees throughout Indiana’s forests and suburban areas.
Look for these caterpillars from late spring through early fall on the leaves of their host trees, particularly in wooded areas, parks, and tree-lined neighborhoods.
4. Spicebush Swallowtail Caterpillar
The Spicebush Swallowtail caterpillar (Papilio troilus) earns recognition as one of nature’s most convincing snake mimics. Mature larvae display a smooth, green body adorned with large, prominent eyespots that create an incredibly realistic snake-head appearance.
This species feeds primarily on spicebush and sassafras, though they’ll also accept red bay and other members of the laurel family. The caterpillars construct silk shelters by folding leaves around themselves, making them somewhat challenging to spot.
Common Mistake: Don’t confuse these with Eastern Tiger Swallowtail caterpillars. Spicebush Swallowtails have more pronounced eyespots and lack the orange coloration found on Tiger Swallowtails.
Search for them in woodland edges, shaded areas, and anywhere their host plants grow naturally. The folded leaf shelters are often easier to spot than the caterpillars themselves.
5. Pipevine Swallowtail Caterpillar
Pipevine Swallowtail caterpillars (Battus philenor) present a striking appearance with their dark reddish-brown to black bodies covered in prominent orange or red spots and short, fleshy projections called tubercles.
These specialized feeders depend entirely on pipevine plants, which grow in Indiana’s southern regions. The toxic compounds they absorb from their host plants make both the caterpillars and resulting butterflies unpalatable to predators.
The caterpillars feed gregariously when young, often found in groups on pipevine leaves. As they mature, they become more solitary and may venture away from the host plant to pupate.
Look for pipevine in moist, shaded areas along streams, woodland edges, and cultivated gardens where this native vine is grown as an ornamental.
6. Painted Lady Caterpillar
Painted Lady caterpillars (Vanessa cardui) display variable coloration but typically appear grayish-black with yellow stripes and branching spines covering their bodies. These cosmopolitan species rank among the world’s most widely distributed butterflies.
These adaptable caterpillars feed on an enormous variety of plants, including thistles, mallows, sunflowers, and many garden plants. Their broad diet contributes to their success across diverse habitats throughout Indiana.
The caterpillars construct silk shelters by webbing leaves together, creating protective hiding places where they feed and rest. Young larvae often feed together in small groups before dispersing as they grow larger.
Important Note: Painted Ladies are migratory butterflies, so caterpillar abundance can vary significantly from year to year depending on migration patterns and weather conditions.
7. Red Admiral Caterpillar
Red Admiral caterpillars (Vanessa atalanta) are easily identified by their variable dark coloration, typically black or dark brown, with rows of branching spines and lighter colored stripes or spots.
These caterpillars show strong host plant fidelity, feeding almost exclusively on nettles. Look for this caterpillar in Indiana near the edge of forests in moist habitats. You’ll find them in areas where stinging nettle and false nettle grow, including woodland edges, stream banks, and disturbed areas.
Like Painted Ladies, Red Admirals construct leaf shelters by folding or rolling nettle leaves and securing them with silk. These shelters provide protection while the caterpillars feed on the enclosed leaf material.
Red Admirals are migratory butterflies. They fly south toward warmer climates in winter and then move north again in late spring when food is more plentiful.
8. Mourning Cloak Caterpillar
Mourning Cloak caterpillars (Nymphalis antiopa) create quite a spectacle when feeding in groups. These dark caterpillars feature white spots along their backs and are covered with branching black spines, giving them a formidable appearance.
These gregarious feeders prefer willow, elm, birch, and poplar trees. Young caterpillars feed together in large groups, creating noticeable defoliation on branch tips. As they mature, they become more dispersed across the tree.
The caterpillars are most active during spring and early summer. Their feeding can be so intensive that entire branches may be stripped of leaves, though established trees typically recover without lasting damage.
Look for them on the aforementioned trees in parks, woodland edges, and areas near water sources where their host trees commonly grow.
9. Cabbage White Caterpillar
Cabbage White caterpillars (Pieris rapae) may appear innocuous, but they’re among Indiana’s most problematic garden pests. In Indiana, this species is often called the Imported Cabbageworm because it isn’t native to North America. It was introduced in shipments of cabbage and other brassica plants and soon became an invasive species.
Coloring is light green with small yellow dots along the sides. This species is small and relatively thin and appears velvety. Despite their modest appearance, one reason Cabbageworms are so damaging is that they are voracious eaters! They can easily skeletonize entire plants, eating everything but the toughest stems and midveins.
These caterpillars target all members of the brassica family, including cabbage, broccoli, cauliflower, kale, and Brussels sprouts. All are capable of producing serious damage to most crucifers.
Pro Tip: For home gardeners, prevention works better than treatment. Use row covers, practice crop rotation, and check plants regularly for the small, white butterflies that lay the eggs.
10. Woolly Bear Caterpillar
The Woolly Bear caterpillar (Pyrrharctia isabella) ranks among Indiana’s most beloved and recognizable caterpillars. Coloring is black with a wide rusty-red band in the middle. As its name suggests, the Woolly Bear caterpillar is covered in dense, coarse hairs.
Woolly Bears are generalist feeders, meaning they will live on and eat nearly any plant! This adaptability helps explain their abundance throughout Indiana in various habitats, from gardens to roadsides to natural areas.
| Woolly Bear Characteristics | Details |
|---|---|
| Size | 1.5-2 inches when mature |
| Diet | Nearly any plant species |
| Habitat | Gardens, fields, roadsides |
| Season | Spring through fall |
| Adult Form | Isabella Tiger Moth |
Common Mistake: While folklore suggests Woolly Bears can predict winter weather based on their color bands, this charming myth lacks scientific basis. Band patterns actually relate to age, diet, and genetics rather than meteorological forecasting.
11. Yellow Woolly Bear Caterpillar
Yellow Woolly Bear caterpillars (Spilosoma virginica) sport dense, pale yellow to cream-colored fuzzy hair covering their entire bodies. These caterpillars transform into Virginian Tiger Moths, creating beautiful white moths with small black spots.
Like their more famous cousins, Yellow Woolly Bears feed on a wide variety of plants, making them common throughout Indiana’s diverse habitats. Their pale coloration helps distinguish them from the more familiar black and rusty-red Woolly Bears.
These caterpillars are most active in late summer and fall, when you might spot them crossing sidewalks or roads as they search for suitable pupation sites. The dense hair provides protection from predators and helps regulate their body temperature.
Find them in gardens, fields, parks, and natural areas where diverse plant communities provide abundant food sources.
12. Eastern Tent Caterpillar
Eastern Tent caterpillars (Malacosoma americanum) are impossible to miss when present, thanks to their characteristic silk tents constructed in the crotches of tree branches. Eastern tent caterpillars have a distinctive white stripe on their backs and lack the gypsy moth’s paired blue and red dots.
These social caterpillars feed primarily on wild cherry, apple, and related trees in the rose family. The conspicuous tents serve as communal shelters where caterpillars rest and molt between feeding periods.
Important Note: While the tents appear alarming, Eastern Tent caterpillars rarely cause lasting damage to healthy trees. The aesthetic impact typically outweighs any actual harm to tree health.
The caterpillars emerge in early spring and complete their development by late spring or early summer. Look for the tents from March through May in orchards, woodland edges, and anywhere their host trees grow.
13. Forest Tent Caterpillar
Forest Tent caterpillars (Malacosoma disstria) create one of nature’s most dramatic displays when populations peak. Unlike their Eastern Tent cousins, these caterpillars don’t construct tents but feed openly on tree foliage in large aggregations.
These caterpillars prefer oak, birch, and other hardwood trees. During outbreak years, their feeding can cause widespread defoliation across entire forests, though trees typically recover by producing new leaves later in the season.
The caterpillars display blue and black coloration with white keyhole-shaped spots along their backs, making them distinctive when examined closely. They move in processional lines between feeding and resting sites.
Key Insight: Forest Tent caterpillar populations follow natural cycles, with outbreak years occurring roughly every 10-15 years followed by periods of low abundance.
14. Luna Moth Caterpillar
Luna Moth caterpillars (Actias luna) rank among Indiana’s most impressive larvae, growing up to 4 inches long. These bright green caterpillars feature a pale stripe along each side and small orange spots, eventually transforming into the spectacular pale green Luna Moths.
These caterpillars feed on a variety of deciduous trees, including hickory, walnut, sweet gum, and birch. Their large size and distinctive coloration make them relatively easy to identify when encountered.
Luna Moths produce two generations per year in Indiana, with caterpillars present from late spring through early fall. The mature caterpillars spin cocoons among fallen leaves, where they overwinter as pupae.
Look for them on their host trees in wooded areas, parks, and suburban landscapes with mature trees. Their size makes them more noticeable than many other caterpillar species.
15. Polyphemus Moth Caterpillar
Polyphemus Moth caterpillars (Antheraea polyphemus) grow into impressive giants, reaching up to 4 inches in length. These bright green caterpillars feature diagonal yellow lines and small orange tubercles, transforming into large, beautiful moths with prominent eyespots.
These versatile feeders accept a wide range of host plants, including oak, maple, birch, willow, and many fruit trees. Their broad diet contributes to their success across Indiana’s diverse habitats.
The caterpillars progress through five distinct growth stages, becoming increasingly impressive with each molt. Mature larvae often draw attention due to their substantial size and striking appearance.
Pro Tip: Despite their intimidating size, Polyphemus caterpillars are completely harmless to humans and actually beneficial as they become important native pollinators.
16. Cecropia Moth Caterpillar
Cecropia Moth caterpillars (Hyalophora cecropia) represent North America’s largest native moth species in their adult form. These impressive caterpillars can reach 4-5 inches in length and display a stunning array of colors and textures.
Young Cecropia caterpillars appear black with rows of orange and yellow tubercles, while mature larvae develop blue-green bodies with colorful knobs and spines. The dramatic transformation between instars makes identification challenging without experience.
These caterpillars feed on numerous trees and shrubs, including maple, birch, apple, willow, and many others. Their ability to utilize diverse host plants helps maintain stable populations across Indiana.
The mature caterpillars construct large, brown cocoons attached to tree branches, where they overwinter before emerging as magnificent moths the following spring.
17. Io Moth Caterpillar
Io Moth caterpillars (Automeris io) demand respect and caution due to their venomous spines. These bright green caterpillars feature distinctive red and white stripes and clusters of branching, stinging spines that can deliver painful welts.
Important Note: Never handle Io caterpillars with bare hands. The spines can cause intense burning sensations, welts, and allergic reactions that may require medical attention.
These caterpillars feed on a wide variety of plants, including corn, roses, willows, maples, and many garden plants. Their broad diet and attractive appearance make encounters likely in both wild and cultivated areas.
The dramatic sexual dimorphism of adult Io Moths—with bright yellow males and brownish females—makes this species particularly interesting to observe throughout its complete lifecycle.
18. Giant Leopard Moth Caterpillar
Giant Leopard Moth caterpillars (Hypercompe scribonia) create quite an impression with their distinctive appearance. Mature giant leopard moth caterpillars are predominantly black, with each segment separated by red bands. From each section springs a cluster of stiff, black spikes rooted in brownish nodules.
Despite their formidable appearance, they are not poisonous. The intimidating spines serve primarily as a deterrent to predators rather than delivering any venom or toxins.
These caterpillars’ primary food source is leafy plants. Though mainly active at night, these caterpillars are frequently seen on roads during autumn as they search for suitable spots to hibernate through winter.
The large size and distinctive appearance make Giant Leopard Moth caterpillars memorable encounters for anyone lucky enough to spot them.
19. American Dagger Moth Caterpillar
American Dagger Moth caterpillars (Acronicta americana) display dense yellow or white hair covering their bodies, punctuated by distinctive black hair pencils projecting from their backs and head.
These caterpillars feed on a variety of deciduous trees, particularly maple, oak, birch, and elm. The long, projecting hairs help protect them from predators while making them easily recognizable to observers.
Common Mistake: While the hairs appear soft and inviting to touch, they can cause skin irritation in sensitive individuals. Observe these attractive caterpillars from a safe distance.
Look for them from mid-summer through fall on their preferred host trees in wooded areas, parks, and suburban environments with mature trees.
20. Hickory Tussock Moth Caterpillar
Hickory Tussock Moth caterpillars (Lophocampa caryae) feature distinctive white hair covering their bodies with prominent black hair pencils at both ends. These attractive caterpillars feed primarily on hickory and walnut trees, though they’ll accept other hardwoods.
The warning coloration and hair pencils serve as effective predator deterrents. While not as dangerous as some species, the hairs can cause mild skin irritation in sensitive individuals.
These caterpillars become most noticeable in late summer and fall when they’re actively searching for pupation sites. The conspicuous appearance makes them relatively easy to identify when encountered.
Find them on hickory, walnut, and other nut trees in wooded areas, parks, and anywhere these trees grow naturally throughout Indiana.
21. White-lined Sphinx Caterpillar
White-lined Sphinx caterpillars (Hyles lineata) showcase remarkable color variation, ranging from green to black with distinctive white or yellow stripes running along their bodies. These large caterpillars feature a prominent horn projecting from their rear end.
These adaptable feeders accept numerous plants, including evening primrose, grape, tomato, and many garden plants. Their broad diet contributes to their success across diverse Indiana habitats.
The caterpillars can appear in significant numbers during certain years, sometimes causing noticeable damage to crops and garden plants. However, they also transform into important nighttime pollinators as adult sphinx moths.
Key Insight: White-lined Sphinx Moths are strong migrants, capable of traveling hundreds of miles, which explains the variable abundance of their caterpillars from year to year.
22. Hummingbird Clearwing Caterpillar
Hummingbird Clearwing caterpillars (Hemaris thysbe) resemble small versions of tomato hornworms, featuring green bodies with diagonal white stripes and a curved horn at the rear. These charming caterpillars transform into day-flying moths that closely mimic hummingbirds.
These specialized feeders prefer honeysuckle, snowberry, and related plants in the honeysuckle family. Look for them in gardens, woodland edges, and anywhere their host plants grow.
The adult moths hover at flowers like tiny hummingbirds, creating delightful garden visitors that many people mistake for actual birds. This remarkable mimicry helps protect the moths from predators.
Search for the caterpillars from late spring through summer on honeysuckle plants, particularly in partially shaded areas where these host plants thrive.
23. Buckeye Caterpillar
Buckeye caterpillars (Junonia coenia) display variable coloration but typically appear dark with orange, white, or yellow markings and rows of branching spines. These caterpillars aren’t poisonous. And they undergo a transformation to become one of Indiana’s most captivating butterflies. The buckeye butterfly has beautiful eye-like spots on its wings that it uses to scare off predators.
These caterpillars feed on a variety of plants, including plantain, snapdragon, and other members of the figwort family. They’re often found in disturbed areas, gardens, and roadsides where their host plants commonly grow.
The caterpillars can be found throughout Indiana’s growing season, with multiple generations per year in favorable conditions. Their adaptability to disturbed habitats makes them relatively common in urban and suburban environments.
24. Viceroy Caterpillar
Viceroy caterpillars (Limenitis archippus) present a distinctive appearance with their mottled brown and white coloration that resembles bird droppings—an effective camouflage strategy. These caterpillars also feature prominent horns projecting from their backs.
These specialized feeders target willow, poplar, and related trees, often found near water sources where these trees naturally grow. The caterpillars construct small shelters by rolling leaves and securing them with silk.
Young Viceroy caterpillars overwinter in these leaf shelters, emerging in spring to complete their development. This survival strategy helps them endure Indiana’s harsh winter conditions.
The adult Viceroy butterflies mimic Monarchs in appearance, benefiting from the protective resemblance to toxic species while being perfectly palatable themselves.
Frequently Asked Questions
Several species can cause skin irritation or painful stings, including Io moth caterpillars (venomous spines), saddleback caterpillars, and various tussock moth species. Always observe caterpillars without touching them unless you’re certain they’re harmless.
Peak caterpillar activity occurs from late spring through early fall, with the highest diversity typically found from June through August when multiple generations overlap.
Plant native host plants for desired butterflies and moths, use targeted control methods like Bt for problem species, and maintain diverse garden habitats that support natural predators.
No, many brightly colored caterpillars are completely harmless. However, bright colors often serve as warning signals, so it’s best to observe rather than handle any unfamiliar species.
Most caterpillar infestations are temporary and rarely cause lasting damage to healthy trees. Monitor the situation, and consider professional consultation only if defoliation is severe or trees show stress signs.
Creating a Caterpillar-Friendly Environment
Understanding these 24 common caterpillars transforms your perspective on backyard biodiversity. Each species plays a vital role in Indiana’s ecosystem, supporting bird populations, contributing to pollination, and maintaining natural balances that benefit your garden and local environment.
Caterpillars contain twice as many carotenoids as other insects. Carotenoids stimulate the immune system, serve as antioxidants, and more, making them essential food sources for nesting birds and other wildlife.
By learning to identify these species, you’re better equipped to make informed decisions about garden management, appreciate the natural processes happening in your yard, and contribute to conservation efforts that support Indiana’s remarkable biodiversity.
Remember that most caterpillars you encounter are beneficial or benign, deserving of observation and respect rather than immediate elimination. The few problematic species can be managed with targeted approaches that preserve the many beneficial insects sharing your outdoor spaces.
