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Brown Caterpillar Identification Guide With Photos

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brown-caterpillar-identification

Identify Your Brown Caterpillar With This Easy and Accurate Guide.

If you have found a brown caterpillar and you're wondering if it will damage your garden, or what it will turn into, then this easy, photo-rich caterpillar identification guide will help.

This guide will answer many of your questions about commonly found North American caterpillars: Does this caterpillar sting? Is it rare? Is it a serious garden or forest pest? Whether you're a young scientist looking for information for a project, a gardener with big brown caterpillars all over your tomatoes, or you simply want to know what that thing crawling across your patio might be, there's something here for you.

How to Use This Guide

For every caterpillar listed, this guide will tell you the following essential information:

  • Does it sting?
  • What does it eat?
  • Will it seriously damage plants or trees?
  • Is it rare?
  • What does it turn into?
  • Can you raise it to an adult?

If you still have questions about identifying the caterpillar you found, there are good internet sources that are species-specific and can give you more detail.

Noctua pronuba, the large yellow underwing

Noctua pronuba, the large yellow underwing

Noctua Pronuba, the Large Yellow Underwing

This interesting insect is becoming one of the most commonly found caterpillars in North America. It is an invasive species, having been introduced in the late 20th century from Europe. Like most cutworm species, this is a chubby brown caterpillar that is frequently found by gardeners digging in the dirt. Cutworms often hide just beneath the surface during the day, and emerge at night to feed on leaves. Some species eat through the plant stalk close to the ground, causing the plant to fall over; this is why they are sometimes called "cutworms."

  • Does it sting? No, cutworms are harmless to people
  • What does it eat? Low plants and garden crops
  • Will it seriously damage plants or trees? If they occur in large numbers, cutworms can damage yard and gardens
  • Is it rare? No, cutworms are very common
  • What does it turn into? Noctua pronuba turns into a handsome moth with yellow and black hindwings
  • Can you raise it to an adult?

The Large Yellow Underwing Moth

brown-caterpillar-identification
brown-caterpillar-identification

Bronzed Cutworm, Nephelodes Minians

This species is representative of nearly all cutworms in North America -- if you find a brown caterpillar while working in the garden, and it looks like this one, then you can be almost certain that it's a cutworm species. It may or may not be the one pictured here, but the differences are so minor that they generally matter only to entomologists and other scientists. For everyone else, a brown caterpillar that looks like this is a cutworm, and it will turn into a brown moth similar to the one pictured here.

Control of cutworms is difficult, and runs the risk of poisoning everything in the soil. If you are losing important food crops to cutworms, then the use of diatomaceous earth, a non-toxic insect control agent, may be warranted.

  • Does it sting? No, cutworms are harmless to people
  • What does it eat? Low plants and garden crops
  • Will it seriously damage plants or trees? If they occur in large numbers, cutworms can damage yard and gardens
  • Is it rare? No, cutworms are very common
  • What does it turn into? Like N. minians, nearly all cutorms turn into medium-sized gray or brown moths.
  • Can you raise it to an adult? Yes, if you're curious to see what it turns into.

Bronzed Cutworm Moth

brown-caterpillar-identification
brown-caterpillar-identification

The Imperial Moth: Eacles imperialis

This huge caterpillar is often found in late summer, when it leaves the comfort of the tree it has been living in and wanders off to find a place to pupate. This species pupates underground and does not spin a cocoon, so it has to find the right place to spend the winter and turn into a moth. Often these caterpillars are found on the ground right before they pupate; at this time their usual green color is dark, almost purple, and they are beginning to contract into the pupal form.

This big caterpillar turns into a very big moth, one of the largest in North America. The imperial moth is perfectly camouflaged to blend into yellowed leaves of poplars and other trees, so despite its size it can be very easy to miss. You are much more likely to see this magnificent species as a caterpillar than the adult moth.

The Basics:

  • Does it sting? No. Although they appear to be intimidating, these big caterpillars are harmless.
  • What does it eat? Sycamores, poplars, oaks, and related plants.
  • Will it seriously damage plants or trees? No, it seldom occurs in enough numbers to do damage.
  • Is it rare? Not really, although it's not often seen.
  • What does it turn into? A huge, yellow and brown moth.
  • Can you raise it to an adult? Yes -- if you find a fully grown one on the ground, you can keep it in a container with a folded paper towel in the bottom. It will crawl around a lot and then find a place in the folds of the paper towel.

Adult Imperial Morh

brown-caterpillar-identification

What Are Caterpillars?

Caterpillars are often very beautiful, but just as often they are plainly colored. Brown caterpillars, for example, are protected from predators by blending in with the background. Many of the brown-colored caterpillars you find while gardening or doing yard work have evolved to blend in with the soil in which they hide.

All caterpillars, brown or otherwise, are the larval stage of the class of insects called Lepidoptera, commonly known as butterflies and moths. They spend their days eating and storing energy for the adult butterfly or moth that they will become. Caterpillars are well adapted to their natural surroundings. Most of them are camouflaged, so even though they're all around us, we usually never see them. They are so perfectly disguised, or have such secretive habits, that we walk right by them without ever knowing they're there. But they are!

Butterflies and moths go through "complete metamorphosis" – that is, they have four distinct stages: egg, larva, pupa, adult. The caterpillar is the larval stage, and all it does is eat and store energy for the adult stage. They are basically eating machines whose only goal is to store fat for the adult stage.

brown-caterpillar-identification

Spilosoma virginica: The Yellow Woolly Bear

This is one of the most commonly encountered of all North American caterpillars. They eat a wide variety of common plants, many of them considered weeds, and they make no real effort to hide -- you can often find them on the top of a leaf in the middle of the day, happily eating. They are typically pale yellow or orange, but some individuals are much darker. The fur is thick but not spiny, and they are very "firendly" -- they don't seem to mind being handled and will harmlessly crawl over your hands (some people with super-sensitive skin may have a mild reaction to the fur). The adult is a beautiful white moth that you may find in the summer around your porch lights.

The Basics:

  • Does it sting? No, although the fur can be irritating to sensitive skin.
  • What does it eat? Mostly low plants and "weeds."
  • Will it seriously damage plants or trees? No.
  • Is it rare? No.
  • What does it turn into? A very pretty white moth.
  • Can you raise it to an adult? Yes.

Spilosoma Virginica, the Yellow Woolly Bear Moth

brown-caterpillar-identification
brown-caterpillar-identification

Genus Hemileuca: Buck Moths

Although these caterpillars come in a variety of shades, they are worth getting to know because all of them can sting. Buck moth caterpillar envenomation is among the most common causes of caterpillar stings, especially in the West and South. They tend to congregate in groups on tree trunks, and can be very well camouflaged; this makes it fairly easy to accidentally put your hand on a group of them, causing a painful sting. This provides the species with increased protection from predators, since an encounter with a large number of this stinging caterpillar is a truly intimidating event.

Buck moths are related to the io moth, which also has a number of less-well-known species and sub-species. In general, it's best to be cautious around caterpillars with bright colors and multiple sets of rosette spines.

The Basics:

Scientific name: Hemileuca species

Food Plant: Mostly oaks

Range: Several species, ranging across the US and into Canada and Mexico

Adult Moth: The adult moths are large, beautiful insects

Severity of Sting: Can be very painful, especially if you come into contact with a group of the caterpillars.

Adult Buck Moth

brown-caterpillar-identification
brown-caterpillar-identification

Abbott's Sphinx, Brown Form

Abbott's sphinx presents a fascinating example of polymorphism -- the occurrence of two or more very different forms within on species. The two caterpillars above look like different species, but they're the same one, and even could have come from the same brood of eggs laid by one female. There's even one more color form, a blue-gray morph with a rounded orange "horn."

The caterpillars eat grape leaves. The adults, which look a like a piece of bark at rest, hover in front of flowers when they feed, making a faint buzzing sound and looking very much like a bumblebee.

The Basics:

  • Does it sting? No. The horn on the tail end appears to be only for show.
  • What does it eat? Grapevines
  • Will it seriously damage plants or trees? No, unless there are many caterpillars present
  • Is it rare? No, in fact this species appears to be becoming more common
  • What does it turn into? A very cool little moth that mimics a bee
  • Can you raise it to an adult? Yes, without much difficulty.

Abbott's Sphinx Adult Moth

brown-caterpillar-identification
brown-caterpillar-identification

Eumorpha pandorus: The Pandorus Sphinx Moth

This bright orange beauty is one form of a somewhat common type of sphinx moth larva -- the other form is green, and while beautiful, is not quite as striking as this one. I've included this caterpillar mainly because I think it's so beautiful – as is the moth it turns into. This caterpillar in the illustration may be a tropical version of the North American pandorus species -- it's a little hard to tell. But if you find one, you can be sure you've found a truly special insect.

The Basics:

  • Does it sting? No.
  • What does it eat? Grape and virginia creeper, among other plants.
  • Will it seriously damage plants or trees? Not usually.
  • Is it rare? This species is not rare but it is seldom seen.
  • What does it turn into? A truly gorgeous moth.
  • Can you raise it to an adult? Yes.

Pandorus Sphinx Adult Moth

brown-caterpillar-identification
brown-caterpillar-identification

Pale Tiger Moth

Perhaps more gray than brown, this species still bears mentioning here since it has a variety of color morphs, some of which are quite brown. This species becomes very commonly found near the end of summer, when the caterpillars crawl down from the leaves they feed on high in trees and search for a place to make a cocoon. At this time they may often be found on tree trunks and around the home, especially on outside porch railings!

Some people and pets may be sensitive to the stiff fur on these caterpillars, although they are not venomous and possess no poison. The cocoons are also protected by the stiff hairs present on the larvae, which are woven into the cocoon. Handling these can result in an irritation similar to working with fiberglass, as the tiny spines become lodged in the skin.

The Basics:

  • Does it sting? No, although the fur can be irritating
  • What does it eat? Maples, oaks, and many other trees
  • Will it seriously damage plants or trees? Not usually.
  • Is it rare? No
  • What does it turn into? A pretty light-brown moth
  • Can you raise it to an adult? Yes, easily, but handle with care

Adult Pale Tiger Moth

brown-caterpillar-identification
brown-caterpillar-identification

Tiger Swallowtail

This rather plain caterpillar turns into one of our most spectacular butterflies, the tiger swallowtail (Pterourus glaucus). It is sometimes seen crawling down the trunks of ash and cherry trees in early summer, looking for a place to pupate.It has two basic color morphs, one green and one brown, but nearly all tiger swallowtail caterpillars are brown by the time they make a chrysalis. This is because the brown color of the pupa becomes visible under the caterpillar's thin skin (exoskeleton).

The adult butterflies are a common sight in parks and gardens, yellow and black beauties that soar high among the treetops, looking for mates and a place to lay their eggs.

The Basics:

  • Does it sting? No.
  • What does it eat? Ashes, wild cherry, apple, and other trees.
  • Will it seriously damage plants or trees? No.
  • Is it rare? No, very common; subspecies occur throughout North America.
  • What does it turn into? A big beautiful tiger-striped butterfly.
  • Can you raise it to an adult? Yes.
brown-caterpillar-identification
brown-caterpillar-identification

Papilio Cresphontes: The Giant Swallowtail

The giant swallowtail can be very common in some years, especially in citrus-growing regions of the American South. The caterpillar is mostly brown, but it is remarkable for the fact that it looks almost exactly like a big bird poop. This is likely an effective way to deter predators.

This species feeds on the leaves of orange and lemon trees, and can sometimes cause considerable damage. Like all swallowtail (Papilio) larvae, they possess a defensive organ called an "osmeterium" that looks like a snake's tongue and smells like rotting fruit.

The adult giant swallowtail is a huge, beautiful butterfly that flies with a characteristic soaring-yet-nervous flight. They appear to be becoming more common in the northern parts of their range.

The Basics:

  • Does it sting? No.
  • What does it eat? The leaves of citrus trees.
  • Will it seriously damage plants or trees? Sometimes.
  • Is it rare? Common southward in the eastern US; similar subspecies throughout the western hemisphere.
  • What does it turn into? A beautiful orange and yellow butterfly.
  • Can you raise it to an adult? Yes.

Adult Giant Swallowtail Butterfly

brown-caterpillar-identification
brown-caterpillar-identification

Megalopygidae opercularis: The Puss Moth, Asp, or Elvis Caterpillar

With its fluffy pompadour hairstyle and general slug-like build, this animal is sometimes referred to as the "Elvis Caterpillar."They are usually brown, but blonde individuals do occur. This is a good species to be familiar with, since it possesses the most potent sting of any North American caterpillar.

The sting of the puss moth is often quite severe, comparable to a wasp sting. It tends to last for several hours or even a day or two; if you have been stung by this species, it's worth calling a doctor to see what you can do about it. If you are allergic to stings, then you should immediately contact a health professional.

Nota bene: There's a moth in the UK called the Puss Moth, but it's in a different family (Notodontidae) and the caterpillars do not have stinging hairs.

The Basics:

  • Does it sting? YES. This caterpillar has one of the worst stings of any caterpillar.
  • What does it eat? Oak, elm, and wild plum.
  • Will it seriously damage plants or trees? No.
  • Is it rare? It's not very common, but it's not rare.
  • What does it turn into? An interesting-looking insect called a "flannel moth."
  • Can you raise it to an adult? Technically yes, but it is hazardous.

Adult Puss Moth

brown-caterpillar-identification
brown-caterpillar-identification

Moths in the genus Heterocampa and related species have distinctive caterpillars that are often brown. They can become quite common in late summer as they crawl on the ground, looking for a place to burrow down and pupate. Although they come in may different colors and forms, these brown caterpillars can often be told by distinct "saddle" markings on the back; even when the color and shape are unusual, the presence of one or more saddle markings can be diagnostic.

The moths are medium sized, drab, and often very furry. Most people never see or notice the adults, but the caterpillars are among the most commonly encountered species at the right time of year.

The Basics:

  • Does it sting? No, these caterpillars are harmless
  • What does it eat? Oak, elm, and many other trees
  • Will it seriously damage plants or trees? No.
  • Is it rare? No, these insects are usually common
  • What does it turn into? A furry brown or gray moth
  • Can you raise it to an adult? Yes

Adult Heterocampa Moth

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Resources

The following sources were used for this guide:

wikimedia.org

https://entnemdept.ufl.edu/creatures/misc

https://entomology.ca.uky.edu/ef003

https://wiki.nus.edu.sg/display

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

Comments

Miebakagh Fiberesima from Port Harcourt, Rivers State, NIGERIA. on June 28, 2021:

GreenMind, thank you for all these detailed information.

Liz Westwood from UK on June 28, 2021:

This is an extremely detailed and well-structured guide. It is so good that it merits bookmarking for future reference and caterpillar identification.

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