10 Most Interesting and Common Caterpillars in New Brunswick

In New Brunswick, a province teeming with biodiversity, there are hundreds of caterpillar species waiting to be discovered. This article aims to shed light on the 10 most intriguing and commonly found caterpillars in the region. First on the list is the Monarch caterpillar, renowned for its plump body adorned with striking black, white, and yellow bands and delicate black tentacles. Feeding primarily on milkweed, it has become a symbol of beauty and resilience. Another fascinating caterpillar is the Woolly Bear, with its dense coat of coarse hairs. Apart from its distinctive appearance, it possesses a fascinating ability to predict the nature of the upcoming winter. If that isn’t captivating enough, wait until you learn about the Viceroy caterpillar, adept at camouflaging itself as bird droppings. And this is just the tip of the caterpillar-filled iceberg in New Brunswick!

Monarch caterpillar


The Monarch caterpillar is undoubtedly one of the most well-known and recognizable species of caterpillar found in New Brunswick. With its plump body adorned in distinctive black, white, and yellow bands, and delicate black tentacles protruding from its head, the Monarch caterpillar is a true marvel of nature. This striking coloration serves as a warning to predators that it is toxic, as it primarily feeds on milkweed plants.

Feeding Habits

The Monarch caterpillar has a unique feeding habit that sets it apart from many other caterpillar species. It exclusively relies on the milkweed plant for sustenance, and in fact, it’s the only plant that Monarch caterpillars can eat. This is because milkweed contains toxic compounds known as cardiac glycosides, which the caterpillars are able to tolerate and store in their bodies. These compounds make the Monarch caterpillar unpalatable and even dangerous to predators, providing them with a natural defense mechanism.

Woolly Bear caterpillar


The Woolly Bear caterpillar, with its distinctive appearance, is easily recognized by its dense coat of coarse hairs. These hairs give it a uniquely fuzzy and woolly appearance, hence its name. Typically, the Woolly Bear caterpillar is black on both ends, with a reddish-brown band in the middle. However, it’s important to note that the coloration of the Woolly Bear caterpillar can vary depending on the region and individual specimens.

Winter Prediction

One fascinating aspect of the Woolly Bear caterpillar is its unique ability to predict the type of winter that lies ahead. According to folklore, the wider the reddish-brown band on the Woolly Bear caterpillar’s body, the milder the winter will be. Conversely, a narrower band is believed to indicate a harsher winter. While this prediction method may not have scientific evidence supporting its accuracy, it still adds a touch of charm and intrigue to observing these delightful caterpillars.

Unique Ability

In addition to its reputation as a winter soothsayer, the Woolly Bear caterpillar possesses another noteworthy ability. As the temperatures drop and winter sets in, the Woolly Bear caterpillar has the remarkable capability to freeze solid. It enters a state known as diapause, during which its bodily functions cease and it becomes almost completely inactive. Then, when spring arrives and temperatures begin to rise, the Woolly Bear caterpillar miraculously thaws out and resumes its life cycle. This remarkable adaptation allows the Woolly Bear caterpillar to survive extreme cold and complete its transformation into a beautiful moth.

Viceroy caterpillar


The Viceroy caterpillar may not boast the vibrant colors and patterns of some other caterpillars, but it certainly knows how to blend in. With its mottled brown or green and white coloring, the Viceroy caterpillar expertly camouflages itself to resemble bird droppings. This clever disguise helps to deter potential predators, as it’s not exactly an appetizing sight. Furthermore, the Viceroy caterpillar features rows of protruding spines on its body, assisting in its defense against would-be attackers.


The camouflage strategy employed by the Viceroy caterpillar is quite effective. By mimicking bird droppings, it makes itself less conspicuous to potential threats, allowing it to go about its activities without drawing unwanted attention. This camouflage adaptation is a testament to the wonders of evolution and the fascinating ways in which organisms have developed to survive and thrive in their environments.

Feeding Habits

When it comes to feeding habits, the Viceroy caterpillar has a diverse palate. It commonly feeds on trees such as willow, poplar, and cottonwood, making these trees its primary sources of nourishment. By munching on these leaves, the Viceroy caterpillar grows and undergoes metamorphosis, eventually transforming into the stunning Viceroy butterfly. This connection between caterpillars and their corresponding adult butterflies or moths serves as a vital reminder of the intricate life cycles and interconnectedness of the natural world.

Large Maple Spanworm caterpillar


The Large Maple Spanworm caterpillar may not be the flashiest caterpillar around, but it certainly boasts a clever disguise. Its gray-brown coloration and slender, elongated body allow it to blend seamlessly into the surroundings, resembling a twig on a tree. This incredible adaptation helps to keep the caterpillar hidden from potential predators, ensuring its safety while it undergoes its transformative journey.


Similar to the Viceroy caterpillar, the Large Maple Spanworm caterpillar utilizes camouflage as a defense mechanism. As it clings to the branches of trees, its natural camouflage allows it to remain inconspicuous, avoiding the attention of predators that may be lurking nearby. This expert disguise showcases the incredible adaptability and resourcefulness of these fascinating creatures.

Host Plants

Unlike some caterpillar species that are highly selective in their choice of host plants, the Large Maple Spanworm caterpillar is relatively versatile. It utilizes a variety of plants and trees as hosts for feeding and development. Among its favored plant choices are maple trees, which not only provide sustenance but also serve as a safe haven for the caterpillar as it undergoes its metamorphosis into a beautiful moth.

Hornworm caterpillars


Hornworm caterpillars encompass several distinct species, but they all share some common characteristics. These caterpillars typically feature a vibrant green coloration with white lines along their bodies and black dots or spots. With an elongated body and a signature “horn” protruding from their rear ends, Hornworm caterpillars have a unique appearance that sets them apart from their caterpillar counterparts.

Different Species

Among the various species of Hornworm caterpillars, two of the most well-known are the Tobacco and Tomato Hornworms. While they are closely related and look remarkably similar, there are subtle differences that distinguish them. The Tobacco Hornworm caterpillar has seven diagonal white lines and a red horn, while the Tomato Hornworm caterpillar has eight V-shaped markings and a black horn.


Unfortunately, Hornworm caterpillars have a reputation for their destructive feeding habits. They voraciously consume the foliage of plants such as tobacco, tomato, and other crops, causing significant damage to these valuable agricultural resources. Their rapid consumption can quickly defoliate plants, posing a threat to farmers and gardeners alike. Proper identification and timely intervention are essential in managing populations of these caterpillars and mitigating their impact on crops.


Because of their similar appearance, distinguishing between the different species of Hornworm caterpillars can be a challenge. However, there are a few key characteristics to look out for. One notable distinction is the presence of the horn on their rear ends, which gives them their name. Additionally, careful observation of the number and arrangement of markings and lines along their bodies can aid in differentiating between species. Consulting resources or seeking guidance from experts can greatly assist in accurate identification.

White-Marked Tussock caterpillar


The White-Marked Tussock caterpillar is easily recognizable thanks to its unique appearance. Covered in tufts of spiky hair and boasting distinctive white markings on its back, this caterpillar stands out from the crowd. While their spiky hairs may appear menacing, it’s important to note that the White-Marked Tussock caterpillar is not venomous.

Effects on Humans

While the White-Marked Tussock caterpillar may seem harmless, it can actually cause some unpleasant effects in humans. Direct contact with the spiky hairs on its body can result in skin irritation and rashes. These reactions are typically mild but can cause discomfort and itchiness. It’s advised to avoid handling these caterpillars without proper protection, such as gloves, to prevent any adverse reactions.

Viral Infections

Interestingly, outbreaks of White-Marked Tussock caterpillars are often alleviated by viral infections. These outbreaks, characterized by large populations of caterpillars consuming foliage, can be temporarily controlled by viruses that naturally infect and decimate the caterpillar population. While the exact mechanics of this phenomenon are not fully understood, it serves as a reminder of the intricate relationships between organisms and the role that natural checks and balances play in maintaining the delicate balance of ecosystems.

Milkweed Tussock caterpillar


Similar in appearance to the Monarch caterpillar, the Milkweed Tussock caterpillar boasts a vibrant black and orange coloration. This striking coloration serves as a warning to potential predators that it is toxic and should be avoided. While it may share similarities with the Monarch caterpillar, the Milkweed Tussock caterpillar has its own unique characteristics that make it a fascinating species in its own right.

Similarity to Monarch

Upon first glance, it’s easy to mistake the Milkweed Tussock caterpillar for its famous counterpart, the Monarch caterpillar. Both species exhibit black and orange coloration and feed on milkweed plants. However, upon closer inspection, several key differences become apparent. The Milkweed Tussock caterpillar lacks the distinctive white and yellow bands seen on the Monarch caterpillar and instead features tufts of black bristle-like hairs along its body.

Poisonous Defense

Just like the Monarch caterpillar, the Milkweed Tussock caterpillar possesses a poisonous defense mechanism. By feeding on milkweed plants, it stores toxic compounds called cardiac glycosides within its body. These compounds render the caterpillar and subsequently, the adult moth that it will metamorphose into, unpalatable and potentially harmful to predators. The bright warning coloration acts as a visual cue, dissuading potential threats from considering the caterpillar as a potential source of food.

Banded Tussock caterpillar


The Banded Tussock caterpillar, despite its name, is not a true member of the Tussock caterpillar family. It is, in fact, the larva of the Pale Tiger Moth. This caterpillar species has a distinctive appearance, with thick black bristles covering its body and distinctive tufts of white hairs along its back. This unique combination of hair types creates an intriguing texture and visual display, making the Banded Tussock caterpillar a remarkable sight to behold.

Not a True Tussock

While its appearance may suggest otherwise, the Banded Tussock caterpillar does not technically belong to the Tussock caterpillar family. Its classification as the larva of the Pale Tiger Moth sets it apart from true Tussock caterpillars, which belong to the Lymantriidae family. Nonetheless, the Banded Tussock caterpillar shares some similarities with its namesake, such as the distinctive tufts of white hairs along its back, which inspired its common name.

Winter Survival

As winter approaches and temperatures drop, the Banded Tussock caterpillar employs a clever strategy for survival. It weaves a protective cocoon among leaves, branches, or other debris using its hairs as reinforcement. This cocoon serves as a shield against the harsh elements of winter, providing insulation and protection for the caterpillar until the arrival of spring. This remarkable adaptation ensures the caterpillar’s continued existence and allows it to complete its life cycle, emerging as a magnificent Pale Tiger Moth.

Parsley caterpillar


The Parsley caterpillar, also known as the Black Swallowtail caterpillar, is a delightful sight with its bright green body adorned with striking markings. It features black and yellow dots or bands along its body, creating a visually appealing pattern. The Parsley caterpillar holds a special place in the hearts of gardeners and butterfly enthusiasts alike, as it is the larval form of the beautiful Black Swallowtail butterfly.

Host Plant

As its name suggests, the Parsley caterpillar primarily feeds on parsley plants. However, it also utilizes other related plants, such as dill and fennel, as host plants. These herbaceous plants provide the necessary nourishment for the caterpillar’s growth and development. Observing the Parsley caterpillar on its host plants can be a rewarding experience, as it showcases the intricate connection between caterpillars and the specific plants they rely on for survival.


The vibrant coloration of the Parsley caterpillar serves as a mechanism of defense and protection. The bright green body, adorned with black and yellow markings, helps to camouflage the caterpillar among the foliage of its host plants. This clever adaptation allows it to blend in with its surroundings, decreasing the likelihood of detection and predation. As the caterpillar continues to grow, it molts its skin multiple times, with each new instar sporting a slightly different pattern and appearance.

Cecropia Moth caterpillar


The Cecropia Moth caterpillar, also known as the Robin Moth caterpillar, is a majestic species that commands attention with its large size and striking appearance. It features a segmented body covered in soft spines, with vibrant colors ranging from green to reddish-brown. The Cecropia Moth caterpillar is a true marvel, captivating observers with its unique attributes.

Coloring Changes

One of the most remarkable aspects of the Cecropia Moth caterpillar is its ability to undergo dramatic color changes as it progresses through its growth stages. When first hatched, the caterpillar displays predominantly green coloration. However, as it matures, its body gradually develops reddish-brown hues, with the final instar displaying a predominantly reddish-brown appearance. This intriguing transformation truly highlights the wonders of metamorphosis and the intricate processes occurring within these caterpillars.

Common Sightings

Late spring and early summer often provide opportunities for encounters with the Cecropia Moth caterpillar. It can be found in various habitats, including woodlands and urban gardens, where its preferred host plants, such as maple, cherry, and birch trees, are abundant. Observing these caterpillars in their natural habitats can be a joyous experience, providing a glimpse into the intricate world of caterpillars and their remarkable transformations into magnificent moths.

Overall, New Brunswick is blessed with a diverse array of caterpillar species, each with its own unique characteristics and adaptations. From the colorful and captivating Monarch and Milkweed Tussock caterpillars to the disguised Woolly Bear and Viceroy caterpillars, these creatures offer a glimpse into the intricate wonders of nature. Exploring the fascinating world of caterpillars not only deepens our understanding of these remarkable creatures but also serves as a reminder of the interconnectedness and beauty of the natural world around us. So, the next time you encounter a caterpillar on your path, take a moment to marvel at its splendor and appreciate the wonders it carries within.

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