The White-marked tussock moth caterpillars, Queen adult butterfly caterpillar, and Monarch caterpillar are three of the most common species of black and yellow caterpillars in the US. You can differentiate them by observing their markings, legs and prolegs, spines, and color variations.
Black and Yellow Caterpillar Identification Basics
Black and yellow caterpillars can be recognized by their unique color patterns, unusual markings, legs, prolegs (also sometimes referred to as false legs), antennae, the presence of hairs or spines, and size.
Some species of caterpillars can also be distinguished by the host plant where they usually stay and eat. Below are some techniques to help you identify the black and yellow caterpillar:
| Check the length | Most black and yellow caterpillars are less than 6 inches long. |
| Look for distinctive markings | Some black and yellow caterpillars have markings that help them look like leaves or a twig. This helps them hide from predators. |
| Observe the legs and prolegs | Most species of black and yellow caterpillars have at least 5 pairs of legs and a pair of prolegs. |
| Note the presence of hair or spikes | Some black and yellow caterpillars have spines or hairs that may irritate your skin when you touch them. |
| Compare what you see with photos online | If you are still unsure what kind of caterpillar you’ve found, you can try to identify it by comparing it to photos online and noting the similarities and differences. If the photos have notes, check those out as well. |
| Observe the colors | Black and yellow caterpillars are usually some combinations of black, white, and yellow in varying degrees. The colors may form stripes, spots, or swirls. |
3 Common Types of Black and Yellow Caterpillars
These are some of the most common black and yellow caterpillars that you can find in the US:
- Monarch caterpillar (Danaus plexippus)
- Queen adult butterfly caterpillar (Danaus gilippus)
- White-marked tussock moth caterpillars
1. Monarch caterpillar (Danaus plexippus)
The Monarch caterpillar (Danaus plexippus) is a medium-sized, plump striped caterpillar with white stripes or white lines, black dots, and yellow stripes.
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The habitat for Monarch butterflies contains milkweed plants and flowering plants. These caterpillars frequent fields, roadside areas, open spaces, wet regions, or urban gardens.
While adult Monarchs consume the nectar of several flowers, they only reproduce in areas with milkweed. This species can be found in South America’s tropical and subtropical areas and thrives during late summer.
2. Queen butterfly caterpillar (Danaus gilippus)
The adult Queen butterfly (Danaus gilippus) frequents North America and South America. It belongs to the Nymphalidae family. The dorsal wing surface of an adult butterfly has orange or brown shades, while the costal regions have black bands and tiny white dots along the forewings.
As for the ventral portion, it’s reddish-brown and mostly appears similar to the dorsal part. Black spots, veins, and tiny white dots with a black border cover the entire surface. The caterpillars are recognizable by 3 pairs of long black spines.
Some of its habitats include meadows, pastures, marshes, deserts, and the periphery of woods. The larval queens consume milkweeds and dogbanes. Caterpillars may live on various food plants, including the honey vine, milkweed, bloodflower, poplars, and butterfly weed.
3. White-marked tussock moth caterpillar (Orgyia leucostigma)
The Tussock moths are known for their plush tufts or tussocks on the ventral parts of the thorax. White-marked tussock moth caterpillars feature 4 white tufts in the front, a bright red head, two little red dots toward the rear, and a black stripe down the middle of their back, bordered by a pale yellow stripe or yellow spots towards the caudal parts.
The White-marked tussock moth caterpillar inhabits willow, maple, ragwort, oak, hackberry, and birch trees. These hairy caterpillars love forests and live in Texas, California, Alberta, and other areas of the US and North America in general.
4 Other black and yellow caterpillars you may find around
There are many other black and yellow caterpillars you may stumble upon in your garden:
| 1. | Cinnabar moth caterpillar (Tyria jacobaeae) | has a drastic appearance with equally thick yellow and black stripes |
| 2. | Dagger moth caterpillar (Acronicta americana) | this caterpillar is fuzzy, with a black head and 3 pairs of long black spines |
| 3. | Catalpa caterpillar (Catalpa sphinx) | has yellow sides and a thick black line on top |
| 4. | Zebra caterpillar (Melanchra picta) | recognizable for dense black stripes and one thick line on top of its body |
Are Black and Yellow Caterpillars Poisonous?
Many black and yellow caterpillars, like the Black swallowtail caterpillar (Papilio polyxenes), pose no threat to people. However, there are still a number of them that are considered poisonous. These creatures have developed powerful defense mechanisms.
One of the most common forms of defenses that they utilize is the discharge of a harmful substance from the caterpillar’s urticating tufts of hair or spiny structures. These hollow, stinging white hairs produce venom that can cause itchy, swollen skin irritation or an upset stomach (when the caterpillars are ingested). While some people will suffer from hives, others might not react.
A lot of these caterpillars can be toxic to pets. This is why you must regularly clean your pet’s favorite spot to reduce the risks of them getting in touch with toxic caterpillars.
Joan is a nocturnal person who loves traveling and coffee. She’s also an animal lover (and rescuer) who makes it a point to befriend every animal she meets. Her passion for learning led her to writing about various topics. As someone who is a nature lover, she aims to continue learning about the wonderful creation—especially butterflies, and at the same time, share her knowledge here at Butterfly Hobbyist.