Milkweed Tussock Moth Caterpillar: Essential Facts for Gardeners and Nature Enthusiasts

The milkweed tussock moth caterpillar is a fascinating creature that calls milkweed plants its home. These caterpillars are known for their unique appearance, covered in thick hairs with black, orange, and white tufts, and their impressive appetite for milkweed leaves.

While many are familiar with monarch butterflies’ connection to milkweed, the milkweed tussock moth caterpillar is another inhabitant that plays a significant role in the milkweed ecosystem. As they mature, these caterpillars can quickly consume large portions of a milkweed plant, leaving behind only the major leaf veins full of latex sap. Interestingly, these moth caterpillars are also equipped with an organ that emits ultrasonic sounds to warn their primary predators, bats, of their unpalatable taste.

Not only do they have a distinguished appearance and unusual features, but their feeding habits also have a noticeable impact on the milkweed plants they call home. As we delve deeper into the world of milkweed tussock moth caterpillars, we’ll find that there’s more to these tiny creatures than meets the eye.

Milkweed Tussock Moth Caterpillar: Overview

Identification and Physical Features

The Milkweed Tussock Moth Caterpillar, scientifically known as Euchaetes egle, has a distinctive appearance with the following characteristics:

• Body color: Orange, black, and white
• Tufts of black hair on their bodies
• A black head

These features make it easy to identify the tussock moth caterpillar among other caterpillars.

The Life Cycle

The life cycle of the milkweed tussock moth caterpillar can be briefly described in four stages:

1. Eggs: Females lay their eggs on the underside of milkweed leaves.
2. Larvae: The caterpillar feeds mainly on milkweed plants, often skeletonizing the leaves.
3. Pupae: After maturing, the caterpillar forms a silk cocoon mixed with its hairs.
4. Adults: The adult moths emerge from the cocoon, with their primary goal being to reproduce.

Distribution and Habitat

Milkweed Tussock Moth Caterpillars can be found in various regions across North America. Their preferred habitat includes milkweed plants, on which they feed and grow throughout their life cycle.

Importance in the Ecosystem and Connection to Milkweed

Role of the Caterpillar in the Ecosystem

The Milkweed Tussock Moth caterpillar plays a crucial role in the ecosystem by contributing to species diversity. A healthy ecosystem supports a variety of species, including insects like these caterpillars. They feed on milkweed plants, which helps control their growth and maintain the balance in their natural habitats. Additionally, they serve as a food source for various predators, such as birds and parasitic insects.

Milkweed as a Host Plant

Milkweed plants come in various species, with common milkweed (Asclepias syriaca) and swamp milkweed being two examples. These plants serve as a vital host plant for Milkweed Tussock Moth caterpillars and several other insect species.

Characteristics of milkweed:

• Produces nectar-rich flowers
• Contains a sticky sap called latex
• Has toxic compounds that deter most predators

For the caterpillar, the milkweed plant offers not only a source of food but also protection due to the toxic compounds found in its sap. As the caterpillars consume milkweed leaves, they absorb the toxins, making them unappetizing to predators.

Comparison of Milkweed Species:

By feeding on various types of milkweeds, these caterpillars contribute to the health of the ecosystem by keeping the milkweed populations balanced and supporting species diversity.

Interactions with Other Species

Monarch Butterflies

Monarch butterflies and milkweed tussock moth caterpillars both rely on milkweed plants for their survival. While monarch caterpillars only consume milkweed leaves, milkweed tussock moth caterpillars can quickly devour entire plants except for the stem. Due to this, competition between them can arise for resources.

Comparison Table

Predators and Defense Mechanisms

Milkweed tussock moth caterpillars have developed defense mechanisms to deter predators. They are covered with orange hairs, indicating toxicity. This is because they consume milkweed containing cardiac glycosides, toxic compounds that make them poisonous to many predators like mammals and birds.

However, some predators, like bats, still target these caterpillars. To avoid predation, milkweed tussock moth caterpillars have an organ that emits ultrasonic sounds, warning bats of their noxious taste.

Features:

• Requires milkweed plants for survival
• Can consume entire milkweed plants quickly
• Fuzzy appearance with orange hairs

Characteristics:

• Toxic due to consumption of milkweed containing cardiac glycosides
• Utilizes ultrasonic sounds as a defense mechanism
• Shares habitat with monarch butterflies and other insects like aphids and dogbane beetles

Tips for Home Gardeners and Naturalists

Encouraging the Growth of Native Milkweed

To support native insects like the milkweed tussock moth caterpillar, consider planting native milkweed species in your garden or yard. Some options include:

• Swamp milkweed (Asclepias incarnata)
• Butterflyweed (Asclepias tuberosa)
• Whorled milkweed (Asclepias verticillata)

These species not only attract the milkweed tussock caterpillar but also provide a habitat for the famous monarch butterfly.

Potential Damage and Management

While milkweed tussock moth caterpillars can be beneficial to ecosystems, they can become quite hungry and cause damage to milkweed plants.

During June and August, female moths lay eggs, which later develop into larvae. These caterpillars feed on milkweed leaves in clusters, leading to an impressive amount of damage. Though they might not fully destroy plants, it’s essential to monitor your milkweed plants.

To manage any damage, consider:

• Inspecting plants regularly for signs of caterpillar infestation
• Promptly handpicking caterpillars from affected plants
• Maintaining a balance of native milkweed plants to share with monarch butterflies

Comparison Table: Milkweed Tussock Moth Caterpillar and Monarch Butterfly Caterpillar

Remember, milkweed tussock moths are native species and contribute to natural diversity. It’s essential to weigh the pros and cons of hosting these insects in your garden and finding a balance that maintains healthy milkweed populations for all native species.

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Milkweed Tussock Moth Caterpillar

help!!!!
Just happened on to your site a couple months ago, and have been raving abt. it to anyone that will listen!!! Great job and service you do. Now, for my bug, er, caterpillar…I found him eating my butterfly weed the other day, and I’m thinking he must be a pest. I brought one of the larvae in when I first found it and it immmediately spun a cocoon…now I’m wondering if I should get rid of it….can you tell me what this is going to be? Thanks, in advance, for your great service!
Pat, St. Louis

Hi Pat,
This is a Milkweed Tussock Moth Caterpillar or Milkweed Tiger Moth Caterpillar, Euchaetes egle. If the caterpillars are plentiful, they may defoliate the host plant. The adult moth has unmarked grey wings and yellow spots on the body.

Letter 2 – Milkweed Tussock Moth Caterpillar

Milkweed Tussock Moth caterpillar?
Location: southern indiana
September 9, 2011 9:55 pm
I found this little guy today on the side of my house and have never saw anything like it. Is this a Milkweed Tussock Moth caterpillar
Signature: Brian

Hi Brian,
Your identification of the Milkweed Tussock Moth Caterpillar or Milkweed Tiger Moth Caterpillar, Euchaetes egle, is absolutely correct.

Letter 3 – Milkweed Tussock Moth Caterpillar

Subject: unusual cattepillar
Location: Charlottesville, VA
August 9, 2014 6:05 am
never saw this before. 3/4″ long, on deck and steps. suburban type back yard with lots of native and non-native plants and vegetable garden.
thank you!!
Signature: Wendy Roberman

Hi Wendy,
The Milkweed Tussock Moth Caterpillar or Milkweed Tiger Moth Caterpillar, Euchaetias egle, is frequently found feeding on milkweed, and it sounds like you may have some among your native plants.

Letter 4 – Milkweed Tussock Moth Caterpillar

Subject: Milkweed Tussock Moth Caterpillar
Location: southwestern Ontario, Canada
August 15, 2015 6:09 pm
I was very excited to see that the milkweed I planted in my mother’s garden was well-munched, but somewhat surprised to discover who was munching it! Not monarchs, as I hoped for, but a milkweed tussock moth caterpillar. There were four or five of these little guys. When disturbed, they curl up into a ball and drop to the ground. I haven’t seen them in this area before and so this spotting was particularly interesting to me. I know you have lots of tussock moth caterpillar photos already, but thought I would send this along in case you found it useful.
Thanks for such a great site and all your hard work!
Signature: Alison

Dear Alison,
Your Milkweed Tussock Caterpillar image is of very high quality and a wonderful addition to our archives.

Letter 5 – Milkweed Tussock Moth Caterpillar

Subject: Tussock moth?
Location: Hancock County, Ohio
November 13, 2015 1:58 pm
Is this a photo of some sort of tussock moth caterpillar? I came across it in Findlay, Ohio this summer. The closest thing I have found that looks like it are the tussock moth caterpillars, but I have not found one even closely resembling this. It was about 1.5 to 2 inches long.
Signature: Ivan

Dear Ivan,
Like the Monarch Butterfly, your Milkweed Tussock Moth Caterpillar, Euchaetias egle, is a species that is always found in association with milkweed.

Many thanks!.  I’m finding out that milkweed is very important to the insect world!

That is why many years ago we created a tag to recognize the complex ecosystem of the Milkweed Meadow.