19 Types of Caterpillars Found in Michigan (With Identification Tips)
Updated June 7, 2026
Michigan is home to a remarkable diversity of caterpillar species, with over 120 species of caterpillars found in the state. These larvae represent the early life stage of some of the most beautiful butterflies and moths in the Great Lakes region, and spotting one — whether on a garden plant, a forest trail, or a suburban sidewalk — is one of the small pleasures of spending time outdoors in the state.
Michigan is one of the states with hundreds of types of caterpillars across trees, shrubs, grasses, and vegetables, with various moth and butterfly caterpillars common across hardwood trees in forests, open areas, and willows throughout the state. Some are beloved icons of autumn, others are important ecological players, and a few are considered pests by gardeners and foresters alike.
This guide covers 19 types of caterpillars found in Michigan, with identification tips to help distinguish each one — from the instantly recognizable Monarch to the surprisingly well-camouflaged Curve-lined Owlet Moth caterpillar.
1. Monarch Caterpillar
The Monarch caterpillar (Danaus plexippus) is one of the most recognizable larvae in all of North America. It is characterized by its plump body, vibrant colors, and distinctive black, yellow, and white bands. There are also tentacles on each end of its body, and the maximum length is about 2 inches.
Monarch caterpillars primarily feed on milkweed plants, which contain toxins that make them unpalatable to predators — a feeding behavior that helps protect both the caterpillars and adult Monarch butterflies from predation. Milkweed plants contain toxins called cardiac glycosides, which Monarch caterpillars sequester in their bodies, making them toxic to predators — a fascinating example of co-evolution and chemical defense.
Pro Tip: Planting native milkweed species in a Michigan garden is one of the most effective ways to attract and support Monarch caterpillars, which depend entirely on milkweed as their host plant.
The caterpillar identification of the Monarch is crucial for conservation efforts, as their populations have been declining due to habitat loss and pesticide use. Look for them in meadows, roadsides, and gardens wherever milkweed is growing, typically from late spring through early fall.
2. Woolly Bear Caterpillar
Few caterpillars in Michigan are as culturally beloved as the Woolly Bear. The Woolly Bear caterpillar (Pyrrharctia isabella) is easily identifiable by its black body and reddish-brown bands, and it can be found in a variety of habitats, including meadows, forests, and even suburban gardens.
As its name suggests, the Woolly Bear caterpillar is covered in dense, coarse hairs and transforms into an Isabella Tiger Moth. Woolly Bears are generalist feeders, meaning they will live on and eat nearly any plant. This caterpillar will grow to be about 3 inches, and it can be found living on porches and sidewalks all over Michigan.
A popular piece of folklore claims that the width of the reddish-brown band predicts winter severity. According to folklore, the wider the reddish-brown band, the milder the winter will be — but this is just a myth, though the Woolly Bear caterpillar remains a beloved symbol of autumn. What is genuinely impressive is its cold tolerance: it can freeze in the ground during winter to come back to life in the spring, thanks to a cryoprotectant substance that ensures vital organs are not affected by freezing.
3. Cabbageworm (Imported Cabbageworm)
The Imported Cabbageworm (Pieris rapae) is a common sight in Michigan vegetable gardens, particularly wherever brassica crops are grown. The Cabbage White caterpillar is a common sight in Michigan gardens, feasting on cabbage, broccoli, and other cruciferous vegetables. The caterpillar itself is smooth and pale green, blending almost perfectly with the leaves it consumes.
Cabbageworms grow into Cabbage White Butterflies, which are one of the most abundant butterflies in Michigan — so if a white butterfly is spotted in spring, chances are it is a Cabbage White. Gardeners should inspect the undersides of brassica leaves regularly for pale yellow eggs, which hatch into the feeding caterpillars. Row covers and hand-picking are among the most effective organic controls available.
Key Insight: The Imported Cabbageworm is not native to North America — it was accidentally introduced from Europe and has since become one of the most widespread caterpillar pests in Michigan gardens.
4. Viceroy Caterpillar
The Viceroy caterpillar (Limenitis archippus) is a masterclass in deception. This caterpillar is mottled green, brown, and white, and is often mistaken for bird droppings — which turns out to be a great defense. Other characteristics include small spines and a horn on the head.
The coloring is mottled brown or green and white to resemble bird droppings, with two dark-colored horns on the head and small spines on the body. The chrysalis also resembles bird droppings hanging from a tree branch. Viceroy caterpillars prefer poplar, willow, and cottonwood trees as their hosts and are mostly found in open forest areas and fields in Michigan.
As adults, Viceroy butterflies are famously similar in appearance to Monarchs, which has long been cited as a classic example of Batesian mimicry. Look for Viceroy caterpillars on willow branches near streams and wetland edges throughout the Lower Peninsula.
5. American Dagger Caterpillar
The American Dagger caterpillar (Acronicta americana) is one of the most striking fuzzy caterpillars found on Michigan hiking trails. Found on hiking trails all over Michigan, these caterpillars’ yellow and white hairs are connected to sacks of toxins, and contact can cause burning, itching, swelling, and rash. Host trees include oak, elm, willow, and maple.
Its dense coat of pale yellow or white bristles makes it look almost fluffy, but those hairs should not be touched. The black “dagger” pencil hairs that project from the body are the key identification feature that sets this species apart from similar tussock moth caterpillars. It is commonly found on deciduous trees in both forested and suburban settings across Michigan from summer into early fall.
Important Note: The American Dagger caterpillar’s hairs are connected to toxin sacs and can cause a painful skin rash. Always observe this species without handling it, and keep children and pets away from caterpillars found on the ground.
6. Spongy Moth Caterpillar
Formerly known as the Gypsy Moth caterpillar, the Spongy Moth (Lymantria dispar) is one of the most ecologically damaging caterpillars in Michigan. These insects have very high populations in Northern Michigan forests, their small hairs can irritate the skin causing a rash, and they are one of the most destructive caterpillars of hardwood trees in the United States.
Spongy moth caterpillars emerge from tan, fuzzy egg masses in April and feed on leaves through late June. Caterpillars are hairy, with a yellow and black head and 5 pairs of blue spots followed by 6 pairs of red spots, and mature caterpillars are 1.5 to 2 inches in length.
The species most often feeds on the leaves of oak and aspen but can also be found on hundreds of other plant species, and its caterpillars defoliate trees, leaving them vulnerable to diseases and other pests, which may lead to tree mortality. Anyone who spots the tan, sponge-like egg masses on firewood, vehicles, or outdoor furniture should report the sighting through Michigan’s invasive species reporting system.
7. Large Maple Spanworm Caterpillar
The Large Maple Spanworm caterpillar (Prochoerodes lineola) is a champion of camouflage. Gray and brown in color, they look exactly like twigs on a tree with knobby bumps all over, and they attach themselves to birch, maple, and willow trees — with blueberry bushes also being a favorite.
This caterpillar moves in a distinctive looping motion, which is characteristic of the geometer moth family. When resting on a branch, its twig-like appearance is so convincing that even experienced observers can walk right past one without noticing. The adult moth is a dull tan or gray color, equally understated compared to some of Michigan’s showier species.
| Feature | Large Maple Spanworm | Viceroy Caterpillar |
|---|---|---|
| Primary Camouflage | Twig mimicry (gray/brown, knobby) | Bird dropping mimicry (mottled green/brown/white) |
| Key Host Trees | Birch, maple, willow, blueberry | Poplar, willow, cottonwood |
| Movement Style | Looping (inchworm-like) | Crawling |
| Adult Form | Dull tan/gray moth | Viceroy butterfly |
8. Eastern Tent Caterpillar
The Eastern Tent caterpillar (Malacosoma americanum) is one of the most familiar spring caterpillars in Michigan. Eastern tent caterpillars are among the three caterpillars that cause the most grief for homeowners in Michigan each spring, and they can be told apart from similar species by their appearance, tent formation, when they are active, and the trees they feed on.
Eastern tent caterpillars are often found munching on wild and ornamental cherries and plums, and the silken tents they form appear around the base of a branch and the trunk. The caterpillars are dark brown or black with a distinctive white stripe running down the center of the back, flanked by blue and yellow markings along the sides.
These caterpillars are social, living in colonies inside their communal silk tents during early spring. They venture out to feed during the day and return to the tent at night. Tents and caterpillars may be removed by hand and placed in soapy water or buried as a control method.
9. Forest Tent Caterpillar
Despite sharing a name with its relative above, the Forest Tent caterpillar (Malacosoma disstria) behaves quite differently. An especially big problem in northern Michigan, forest tents are long and green with an intricate black, gold, and white pattern on each segment of their back. Crucially, despite the name, this species does not build a true tent — it forms a silken mat on tree trunks instead.
Forest tent caterpillars have staged massive outbreaks in the northern Lower Peninsula, with the area between Cadillac and Traverse City and surrounding areas being particularly hard hit. These caterpillars have a voracious appetite and can quickly defoliate trees in Michigan during a population outbreak. While it may be unsightly, the trees usually recover just fine. Interestingly, these caterpillars have regional tastes, and the specific trees they prefer are highly dependent on their location.
One of the most effective natural controls of forest tent caterpillar is Sarcophaga aldrichi, better known as the friendly fly, which is a major factor in the collapse of forest tent caterpillar populations.
10. Red-spotted Admiral Caterpillar
The Red-spotted Admiral caterpillar (Limenitis arthemis) is another Michigan species that relies on camouflage rather than bright warning colors. Red, white, and black coloring is specific to the adult Red-spotted Admiral, while caterpillars are dominated by a red-brown color. Like the Viceroy caterpillar, young Red-spotted Admiral larvae mimic bird droppings as a primary defense strategy.
The caterpillars eat a wide range of leaves in fruit-bearing trees and are considered a potential garden threat. Red-spotted Admiral caterpillars live on and eat different tree leaves depending on their region, with most caterpillars of this species preferring to eat aspen leaves. Birch and cherry are also commonly used host trees in Michigan.
11. Milkweed Tussock Moth Caterpillar
The Milkweed Tussock Moth caterpillar (Euchaetes egle) is a striking, bristly creature that shares a host plant with the Monarch. Characterized by black and white hairs with tufts of orange, the Milkweed Tussock Moth gets its name from its host. In later instars, the caterpillar develops distinct black, white, and orange tufts of hair arranged in bold, contrasting patterns across its body.
The toxins from the milkweed plant are so strong that blue jays have been known to vomit right after eating one of these caterpillars — a testament to just how effective the chemical defense derived from milkweed truly is. Look for clusters of Milkweed Tussock Moth caterpillars feeding together on milkweed leaves in late summer, often stripping entire plants before moving on. For a broader look at Michigan’s moth and butterfly species, Butterflies and Moths of North America maintains a regional identification database.
12. Mourning Cloak Caterpillar
The Mourning Cloak caterpillar (Nymphalis antiopa) is one of the spikiest-looking larvae a Michigan nature observer is likely to encounter. It is black with small white dots scattered across its body, and a row of red-orange spots runs along its back. Rows of branching black spines project outward from each body segment, giving it a formidable, almost menacing appearance.
Despite its dramatic look, the Mourning Cloak caterpillar is not venomous or harmful to handle. It feeds gregariously in early instars, with groups of siblings often found clustered together on willow, elm, cottonwood, and hackberry trees. The adult Mourning Cloak butterfly is one of the longest-lived butterflies in North America and is one of the first to appear each spring in Michigan, having overwintered as an adult. Bird Watching HQ’s Michigan caterpillar guide provides additional photos for comparison.
13. Variegated Fritillary Caterpillar
The Variegated Fritillary caterpillar (Euptoieta claudia) is a boldly marked species found in open habitats across Michigan. With red, white, and black stripes, this caterpillar has little spines that stick out on each segment of its body. These caterpillars live in meadows, open fields, and open lots in Michigan, and they usually attach themselves to any form of violet for a host.
The alternating red and white stripes, combined with the branching spines, make this caterpillar one of the more visually distinctive fritillary larvae in the Midwest. Passionflower, stonecrop, and purslane are also recorded host plants in addition to violets. The adult butterfly is orange with a complex black-and-brown patterned underside, making it a rewarding find for any nature enthusiast.
14. Curve-lined Owlet Moth Caterpillar
The Curve-lined Owlet Moth caterpillar (Phyprosopus callitrichoides) is one of Michigan’s most impressive camouflage artists. Preferring the Greenbrier as a host, this caterpillar has great camouflage where it looks like a dried, curled leaf. Its body is mottled brown, tan, and cream, with an irregular, crinkled texture that replicates the look of a dead or partially curled leaf with remarkable precision.
This species is rarely noticed by casual observers precisely because its disguise is so effective. When encountered on a Greenbrier vine, it holds its body in a slightly curled posture that enhances the dead-leaf illusion. It is a relatively uncommon find, making a confirmed sighting a genuine treat for anyone interested in Michigan caterpillar identification. Browse the full state listing at CaterpillarIdentification.org’s Michigan database for additional reference images.
15. White-lined Sphinx Caterpillar
The White-lined Sphinx caterpillar (Hyles lineata) is the larval form of one of Michigan’s most striking moths. Caterpillars of the white-lined sphinx have multiple color morphs, making them challenging to identify. They are usually light green with a horizontal yellow or yellow-and-black stripe across each side of their body and also have a series of orange or yellow spots parallel to the stripe.
A tail-like spine protruding from the back of the body is typical for sphingid moth caterpillars, known as “hornworms.” This horn, which may sometimes be yellow and have a black tip, is not a stinger, and the caterpillars are not harmful to humans. The caterpillars have a very broad host plant range that includes many species of wild grape, purslane, primrose, apple, peony, and spurge.
Common Mistake: The horn at the rear of White-lined Sphinx caterpillars is often mistaken for a stinger. It is purely decorative and poses no threat — the caterpillar is completely harmless to handle.
16. Spurge Hawk Moth Caterpillar
The Spurge Hawk Moth caterpillar (Hyles euphorbiarum / Hyles euphorbiae complex) is a member of the sphinx moth family and a close relative of the White-lined Sphinx. Like other hawk moth caterpillars, it carries the characteristic posterior horn and a stout, smooth body. Its coloration is typically striking — often featuring bold patterns of black, red, yellow, and white that serve as warning coloration, since this species can sequester toxins from its spurge host plants.
Species such as Hyles euphorbiae do sequester toxins from their hosts, though they do not pass them on to the adult stage. This makes the caterpillar stage the most chemically defended part of the life cycle. In Michigan, this species is most likely to be found wherever spurge plants are established, including roadsides and disturbed habitats. The adult moth is a beautifully patterned hawk moth with pink-and-olive wing markings.
17. Hummingbird Moth Caterpillar
The term “Hummingbird Moth” is commonly applied to several sphinx moth species in Michigan, most notably the Hummingbird Clearwing (Hemaris thysbe). Sphingid caterpillars are medium to large in size with stout bodies. They have five pairs of prolegs, and usually their bodies lack any hairs or tubercules, but most species have a “horn” at the posterior end, which may be reduced to a button or absent in the final instar.
The hummingbird clearwing is a diurnal species that looks very similar to the snowberry clearwing in terms of body shape and size. However, its coloration is different, with rich reds and olive-greens that make it appear even more hummingbird-like than other sphinx moths. The caterpillar of the Hummingbird Clearwing is typically green with pale diagonal side stripes and a blue or black horn. It feeds primarily on viburnum, hawthorn, and cherry in Michigan. Ohio State University Extension’s sphinx moth guide provides an excellent visual comparison of related species.
18. Yellow Underwing Caterpillar
The Yellow Underwing caterpillar (Noctua pronuba) may lack the visual drama of some Michigan species, but it more than makes up for it in agricultural impact. Of all the caterpillars in Michigan, this one is perhaps the most feared by farmers. These caterpillars, which eventually morph into the Yellow Underwing moth, are extremely destructive to crops. Not picky about what they eat, they have caused great agricultural and therefore economic damage throughout Michigan, chomping through alfalfa, grass hay, Swiss chard, squash, and beets.
The caterpillar itself is a dull brownish-gray or greenish color with faint darker lines running along the body — unremarkable in appearance but devastating in large numbers. Large Yellow Underwings have a longer lifespan than many other moth species. In captivity, males live an average of 55 days and females about 75 days, despite only having one new generation per year. Gardeners and farmers who find cutworm-style damage at the soil line should check for this species feeding at night.
| Caterpillar | Key Color/Pattern | Primary Host Plants | Potential Concern |
|---|---|---|---|
| Yellow Underwing | Dull brownish-gray, faint lines | Alfalfa, grass, beets, squash | Serious crop pest |
| Cabbageworm | Smooth pale green | Cabbage, broccoli, kale | Garden pest |
| Spongy Moth | Hairy, blue + red spots | Oak, aspen, many hardwoods | Invasive forest pest |
| Eastern Tent | Black/white stripe, blue markings | Cherry, plum, apple | Ornamental tree pest |
19. Black Swallowtail Caterpillar (Parsley Caterpillar)
The Black Swallowtail caterpillar (Papilio polyxenes), commonly called the Parsley Caterpillar, is a garden favorite across Michigan. Parsley Caterpillars, sometimes called parsley worms, are the larva of the Black Swallowtail butterfly, and they get their name from their preferred host and favorite snack, the parsley plant.
These bright green larvae have black rings and yellow dots. They are definitely a pest if the gardener grows parsley, as that is their host plant — but it will be worth a few leaves once they turn into the beautiful Black Swallowtail butterfly. These caterpillars have a unique defense mechanism called an osmeterium, a forked, orange-colored gland that they can protrude from their head when threatened, emitting a foul odor to deter predators.
At first glance, it is easy to mistake a Parsley Caterpillar for a Monarch, but the coloring is slightly different and the stripes on the Monarch Caterpillar are a bit thinner. Black Swallowtail caterpillars are often found on plants in the parsley family, including parsley, dill, fennel, and carrots, as these plants provide the caterpillars with essential nutrients and support their growth. For more on Michigan’s butterfly and moth species, the Butterflies and Moths of North America regional guide is an excellent reference, and the MSU Extension caterpillar resource offers expert guidance on common Michigan species.
Pro Tip: Planting a dedicated “sacrifice patch” of dill or parsley away from the main herb garden is a simple way to welcome Black Swallowtail caterpillars without losing a prized herb crop. The reward — watching the adult butterfly emerge — is well worth it.
Michigan’s caterpillar diversity reflects the richness of its forests, wetlands, meadows, and gardens. Whether a fuzzy Woolly Bear crossing a sidewalk in October or a boldly banded Monarch feeding on milkweed in August, each of these 19 species plays a role in the state’s broader ecosystem — as pollinators in their adult forms, as food sources for birds and other wildlife, and as one of nature’s most compelling examples of transformation. Taking time to identify these larvae is one of the most rewarding aspects of spending time outdoors in Michigan.