Mourning Cloak Caterpillar: All You Need to Know for a Fascinating Discovery

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The Mourning Cloak Caterpillar is a fascinating creature, known for transforming into the beautiful Mourning Cloak Butterfly. These butterflies are easily recognizable by their unique coloration, featuring yellow or white bands surrounding reddish spots on dark wings, resembling a cloak worn during mourning periods in medieval Germany and Scandinavia.

Throughout its life cycle, the Mourning Cloak Caterpillar displays stunning characteristics. As a spiny elm caterpillar, it showcases red spots, white speckles, and notable spines. As they grow and change, these caterpillars eventually become one of the longest-lived butterfly species in North America, with some Mourning Cloaks living for nearly a year as adults. Their intriguing features, hardy nature, and broad distribution make this species a fascinating topic for nature enthusiasts and lepidopterists alike.

Mourning Cloak Caterpillar: Basic Overview

Nymphalis Antiopa

Mourning Cloak Caterpillar (Nymphalis antiopa) is a fascinating caterpillar species. It transforms into a beautiful butterfly called Mourning Cloak, which belongs to the family Nymphalidae.

Distribution and Habitat

The species is native to North America and can be found in various habitats such as forest edges, parks, and gardens. It can also be found in the temperate regions of Eurasia.

Size and Appearance

Mourning Cloak Caterpillars are 2-3 inches long, with a velvety black body and small red or orange markings on their outer edges. They have fascinating spiky structures called tubercles, which can be quite noticeable.

Life Cycle

The life cycle of Nymphalis antiopa can be divided into four stages: egg, larva, pupa, and adult. Here’s an overview:

  • Egg: Female butterflies lay clusters of greenish eggs on branches, mostly close to larval food sources.
  • Larva: The caterpillar stage begins after hatching and lasts about three weeks. Larvae feed mostly on willow, elm, poplar, and cottonwood leaves.
  • Pupa: This stage, also known as chrysalis, lasts for up to two weeks. The caterpillar forms a pupa that hangs from a branch or other substrate.
  • Adult: Mature Mourning Cloak butterflies emerge from the pupae, with their unique wing coloration serving as camouflage.

In general, Mourning Cloak Caterpillars are fascinating creatures that contribute to the beauty of the natural world.

Behavior and Habits

Feeding Preferences

Mourning Cloak Caterpillars, also known as spiny elm caterpillars, are selective in their diet, primarily feeding on:

  • Elm
  • Willow
  • Cottonwood
  • Birch
  • Hackberry

These caterpillars consume tree sap from host plants in springtime, ensuring their survival through the season.

Reproduction and Mating

Mourning Cloak Caterpillars undergo a fascinating metamorphosis process. After mating in spring, they lay eggs on host plants, which hatch into small, spiny caterpillars. These caterpillars develop into tough, maroon-brown butterflies, with a distinctive yellow border and blue spots on the wings. The full transformation typically occurs in the early summer months.

Overwintering and Hibernation

An impressive feature of Mourning Cloak Caterpillars is their ability to overwinter, or survive through the cold winter months. They achieve this by:

  • Sheltering in tree bark crevices
  • Hibernating as adults
  • Waking up in early spring to feed on tree sap

This adaptive behavior enables the Mourning Cloak to have a longer lifespan than many other butterfly species—up to a year as adults.

Recognition and Identification

Color and Pattern

Mourning cloak caterpillars have distinct color patterns. They are primarily black with small white dots and a line of reddish spots along their backs. Another defining feature is the presence of spines, which are also black, and dark red legs source.

Wings and Wingspan

When the caterpillars transform into mourning cloak butterflies, their wings become maroon-brown with yellow borders. Inside these borders, a row of small blue spots is visible source. They have a wingspan of 2¼ – 4 inches (5.7 – 10.1 cm) with short projections/tails on both wings and irregular borders source.

Sexual Dimorphism and Markings

Mourning cloak butterflies do not show strong sexual dimorphism, meaning males and females appear similar. Both sexes share the maroon-brown color, yellow borders, and blue spots on their wings source.

Host Plants and Preferred Trees

Elm and Aspen

Mourning Cloak Caterpillars are known to feed on various trees, including members of the elm family, Ulmaceae (Ulmus spp.) and aspen trees (Populus spp.)1. Some examples of elms are:

  • American Elm
  • Slippery Elm

Willow and Cottonwood

Another major host family for these caterpillars is the Salicaceae family, particularly willows (Salix spp.) and cottonwoods (Populus spp.)1. For instance:

  • Weeping Willow
  • Black Cottonwood

Maple and Birch

They can also feed less commonly on maples (Acer spp.) and birch trees (Betula spp.)1. Here are a couple of examples:

  • Sugar Maple
  • Paper Birch

Oak and Hackberry

Additionally, they may consume leaves from the oak family Fagaceae (Quercus spp.) and hackberry family Celtidaceae (Celtis spp.)1. Examples include:

  • White Oak
  • Common Hackberry

Deciduous Trees

In general, Mourning Cloak Caterpillars show a preference for deciduous trees (leaves shed annually)1. Some of their preferred trees are:

  • Elm
  • Willow
  • Aspen
  • Cottonwood

Pros

  • Survival: Caterpillars have adapted to eat a wide range of tree species.
  • Flexibility: Allows for a greater chance of finding suitable food sources.

Cons

  • Harm: Trees can sustain damage due to caterpillar feeding.
  • Pests: Mourning Cloak Caterpillars could become pests if they infest a large number of host trees.

Footnotes

  1. (https://entnemdept.ufl.edu/creatures/bfly/mourning_cloak.htm) 2 3 4 5

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 – Morning Cloak Caterpillar

 

unknown caterpillar – Junonia?
Thanks for your great website. A neighbor found six of these caterpillars on the sidewalk (Carlsbad, CA; July 30; we had some unusual rainy weather the previous night). Based on what we’ve found on the web, it appears like it might be in the Junonia genus. We’d welcome a positive id for this. Whenever we find caterpillars, we let our kids observe them and see if they form a chrysalis. We’d also like to know what to feed them. We tried basil and parsley, but they are not eating. Also, what kind of environment do they prefer for pupating? Thanks
Mike & Sue

Hi Mike and Sue,
This is a Morning Cloak Caterpillar. They feed on willow, poplar and elm and are also reported on Floss Silk Trees. If they were found on the sidewalk, they may have been wandering in search of a good place to pupate. The hanging pupa are often found on the sides of buildings. We have seen many adults this year near our Mt. Washington, Los Angeles office.

Authors

  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

    View all posts
  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

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Tags: Mourning Cloak Caterpillars

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