Caterpillars are some of the fascinating bugs in Minnesota; not only do they look fantastic and grow to be over 5 inches long, but their transformation from caterpillar to butterfly (or moth) is something you must see to believe!
These types of caterpillars in Minnesota will tell you what caterpillars there are, where you can find them, how long they take to turn into adult butterflies or moths, and what they eat while they’re larvae.
1. Monarch Caterpillar
Monarch caterpillars are a type of caterpillar in Minnesota; they have a striking orange color and are abundant during springtime.
They can be found on milkweed plants, which are also crucial for other reasons.
Monarch butterflies have been disappearing at alarming rates, making protecting these beautiful creatures more critical.
One way to help protect monarchs is by growing their favorite food: milkweed! Most native species prefer white or common milkweed, but you can also grow swamp milkweed for a different look.
2. Cabbageworm
Larvae are green caterpillars in Minnesota with small yellow or white spots; they grow to a half-inch in length.
They also have blue areas on their sides, which is an excellent way to tell them apart from other caterpillars.
Cabbageworms feed on plants like cabbage, kale, broccoli, collards, and Brussels sprouts.
They’re also known as cabbage worms; the adult moth is brownish gray with black zigzag lines across its wings and has a wingspan of about an inch.
The cabbageworm moth is nocturnal and comes out at night to lay eggs on leaves that will become food for larvae once they hatch.
In addition to laying eggs, adult moths drink nectar from flowers during the day.
3. Woolly Bear
Contrary to popular belief, woolly bears are not types of caterpillars in Minnesota but are types of moths. But that doesn’t mean they aren’t attractive!
As larvae, woolly bears undergo complete metamorphosis: their bodies transform from tiny, wormlike insects into giant hairy moths—and along that journey, some weird things happen to them.
During winter, for instance, these creatures stop moving and secrete a waxy substance that helps keep them dry.
This gives them an ursine appearance that inspired one of their common names: snow bear (or snowfall). It also makes it look like they have cute little beards!
4. Viceroy Caterpillar
The variegated fritillary (Speyeria radiate [Geyer]) is a medium-sized butterfly that often feeds on aspen, birch, elm, willow, oak, viburnum, and hackberry.
It has several larval forms, including a green form with red spots (typically found along stream edges or on wet rocks), an orange form (usually found under logs or on fallen tree trunks), and a brown form that feeds mainly at night.
The larval food plants include willow (Salix spp.) and poplar (Populus spp.). This insect can be seen from early May through late June.
5. Large Maple Spanworm
The Large Maple Spanworm is a common forest type of caterpillar in Minnesota, and they feed on wild Black Cherry, Red Maple, Sugar Maple, White Ash, Box Elder, and other trees.
The larvae are primarily green with yellow stripes. Adults are brown moths with red-tipped wings that emerge from June until August.
They can be found during daylight hours, resting on trunks or branches under leaves or debris where they resemble dead leaves or twigs.
They have been reported flying occasionally but spend most of their time walking. Mature caterpillars may fall to ground level to pupate underground.
Larvae do not make webs but instead wander, looking for food. Black Swallowtail: As you might guess from its name, Black Swallowtails favor black cherry trees and apple, elm, and ash trees for egg-laying sites.
6. Variegated Fritillary Caterpillar
This caterpillar looks more like a snake than a moth; the gray, brown, and yellow stripes along its back (and black head) are often mistaken for eyes by predators like birds.
Some even mimic poisonous snakes by wriggling their bodies as they wiggle on their backs.
It is one of many types of caterpillars in Minnesota that will be collected as part of Project Feeder Watch, a nationwide winter butterfly survey run by monarch experts at Cornell University.
Starting in 1993, it has become a meaningful way to track monarch migration patterns because butterflies lay eggs on specific plants that grow at different latitudes or elevations.
7. Curve-lined Owlet Moth Caterpillar
The curve-lined owlet moth caterpillar in North America is found on black cherry trees.
Although these caterpillars only take two weeks to mature into full-sized moths, they can prove tricky to find since they tend to hide during most daylight hours.
When night falls, however, these caterpillars are often more than willing to come out and play.
Like most moths, their diet consists almost exclusively of leaves from plants such as cherry trees and ash trees.
As a bonus for amateur naturalists like yourself who happen upon a cluster of these colorful little critters, it should be noted that members of the genus Hemileuca are known for exhibiting luminescence when upset.
8. White-marked Tussock Caterpillar
(Dasychira meridionalis) – The White-Marked Tussock caterpillar has two color variations: white with black markings or orange with black markings.
These types of caterpillars in Minnesota are found on numerous plants, including aspens, birches, cherry trees, currants, dogwood shrubs, goldenrods, hackberries, hazelnuts, linden trees, maples (red maple varieties), oaks (white oak varieties), pines (dens-canopy pine varieties), plums trees raspberries and willows.
Caterpillar food sources can vary greatly depending on location; look for small groups feeding along stems or leaves of trees or shrubs during summer.
9. Milkweed Tussock Caterpillar
These caterpillars in Minnesota are often seen in gardens, parks, and roadsides on milkweed plants.
They appear black with bright green dots when they are small but turn brown as they grow larger.
As their name suggests, tussock caterpillar bodies have tufts or clumps that look like a row of black hairs.
These tufts give them extra protection from predators. Rubbing these fibers together can also create a pungent odor that discourages birds from eating them.
Also known as woolly bears because of their brown coloration and scruffy-looking hairs, tussock caterpillars overwinter as larvae before turning into moths during springtime.
10. Banded Tussock Caterpillar
Found across much of Minnesota, banded tussock caterpillar larvae have a brown head with a broad yellow stripe down their back.
The body is covered with grayish-black hair; this species feeds on wild cherry, birch, oak, basswood, maple, and willow trees; it has also been seen feeding on fields like alfalfa and clover.
Adults are long-winged moths that can be found from late May through July feeding on flower nectar or gathering minerals for egg laying.
Eggs hatch into dark brown or reddish-brown caterpillars that are about an inch long when fully grown; larvae resemble bird droppings as they feed at night on leaves.
11. Giant Leopard Moth Caterpillar
The giant leopard moth caterpillar is one of those bugs that seem designed specifically for children’s books.
This colorful fellow can grow up to two inches long and has a body that looks like an ear of corn with orange, black, green, brown, gray, and white coloring. As you might guess from its name, it resembles a leopard.
Giant leopard moths are some of the largest moths in North America and types of caterpillars in Minnesota—the wing span can be as large as six inches!
When these creatures aren’t laying their eggs on lilac trees or habanero peppers (so their babies have something to eat), they reside throughout Canada from Yukon Territory to British Columbia.
12. Parsley Caterpillar
The Parsley Caterpillar is an Eastern tent caterpillar native to parts of North America. It’s a destructive pest, causing large-scale defoliation in their direct vicinity.
Luckily, they are not as common types of caterpillars in Minnesota.
They can be found in members of the Apiaceae family, including anise, carrot, celery, coriander/cilantro, dill, and parsley.
However, they’ve also been known to attack crops like cotton or potatoes.
A healthy individual will consume up to 10 leaves per day while they are small, but once they grow larger, they need more food, so it becomes problematic if their population is high enough.
13. Eastern Tiger Swallowtail Caterpillar
Considered one of Minnesota‘s most beautiful caterpillar species, eastern tiger swallowtail caterpillars have a green body with three diagonal yellow stripes on each side.
They have black dots along their sides, which look like eyes. Six blue dots on its tail form a small butterfly shape.
Butterfly Gardener says their life expectancy is approximately five weeks from hatching to pupation.
The website also reports that people usually find them crawling up tree trunks or around other woody plants growing near water sources like creeks or wetlands.
They typically live for about two weeks before they pupate; after seven days as pupae, they emerge as adult butterflies.
However, it’s important to remember that Minnesota has hundreds of types of caterpillars!
14. Cecropia Moth Caterpillar
The Cecropia moth is one of two giant silk moths across North America.
Large, green caterpillars can be found throughout Minnesota on trees including ash, basswood, birch, elm, hackberry, hickory, and oak; you’re likely to find them from late summer through fall.
These beautiful creatures are harmless (and beneficial); you’ll find them widely throughout the Eastern USA and Canada.
The Cecropia silkworm is also known as the inchworm because that’s exactly how they move—one slow step at a time.
Once they reach their fifth instar (or phrase), they begin spinning their cocoons, emerging as beautiful moths in July or August.
15. Monkey Slug
This bright green caterpillar is a common sight across most of central, southern, and western Minnesota.
Its body is covered with white polka dots that are shaped like an inverted V; each drop has two horns coming out from it.
It feeds on various trees, including ash, birch, elm, hackberry, honey locust, maple, oak, and walnut.
Found mostly on deciduous trees, they can also be found on elm, hickory, and willow trees. [Source: Minnesota Department of Natural Resources]
16. Spotted Apatelodes Caterpillar
These fuzzy, black caterpillars, also known as a snout moth caterpillar, have tiny yellow dots. You can find them on oak trees from May through July.
They are relatively large, reaching up to 7 cm (2.5 inches) long. The spotted apatelodes feed primarily on oaks but have also been found on hickory, elm, and willow trees.
You’ll recognize one of Minnesota’s more distinctive types of caterpillars by its pattern and unique shape. These tend to be bushy with narrow tails, which end in small tufts at their ends.
Like many other types of caterpillars in Minnesota, they like feeding on oak trees—though they’re not picky about what species they eat.
17. Io Caterpillar
The Io caterpillar, Automeris io, is a beautiful metallic blue-green color. While they are lovely to look at up close, these little critters pack quite a wallop.
Should you encounter one, seek shelter or cover and call an exterminator (or someone who knows what they’re doing).
These critters have urticating hairs that can cause skin rashes upon contact with sensitive skin.
Typically found on oak trees during late June through early July, these types of caterpillars in Minnesota are best viewed from afar with binoculars or any zoom lens.