Dive into the world of butterflies found in Vermont

Monarch vs. Viceroy: The Lookalikes

Some butterfly species evolve to look alike. There are many reasons they may do this. In the case of the monarch and the viceroy, it’s mutually beneficial. Both are foul-tasting to their predators. After an initial attempt to eat one, a potential predator might steer clear of both species.

Photo: A close-up view of a monarch’s wing.

The adult butterflies’ appearance might fool you, too. But there are a few key differences between these mimics:

Size: Monarch butterflies are one of the largest species in Vermont. Their wingspan can be up to five inches. Viceroy butterflies’ wingspan gets up to a little over three inches.

Black stripe: Look at the smaller hind wing. Viceroy butterflies have a black stripe going across the vertical veins. The monarch’s veins are uninterrupted.

Photo: Top, a monarch butterfly. Bottom, a viceroy butterfly, taken by Jack Forrester. CC BY 4.0. Cropped from original.

Caterpillar: The mimicry only begins in the adult phase. The caterpillars are quite distinct. Monarch caterpillars have yellow, white, and black stripes. They exclusively eat milkweed. Viceroy caterpillars are a mottled brown and white that resembles bird droppings. They eat willow and poplar leaves.

Photo: Top, a monarch caterpillar, taken by saylorj. Bottom, a viceroy caterpillar, taken by shcrifield. Both CC BY 4.0. Cropped from originals.

Migration: Monarchs are famous for their annual migration. They travel en masse from the Northeast to Mexico for the winter. Usually, a single generation makes the entire flight south in the fall – they generally do not breed during the journey. Coming back north, it takes multiple generations to reach the northern United States and Canada each summer. Viceroys overwinter in Vermont in their larval or caterpillar form. They roll up in the leaves of their host plant (willow or poplar) and go dormant. When the air warms in the spring, they form a chrysalis.

Photo: A Monarch butterfly resting on an orange flower.

Painted Lady: The Cosmopolitan

Painted lady butterflies, like monarchs and viceroys, come from the Brush-footed butterfly family. They have similar orange and black coloring, but they have eyespots and more brown on their wings. They’re also smaller, with a wingspan of about two inches. Like monarchs, they migrate, but their migrations are less predictable and they tend to fly higher. That makes their migration harder to observe.

Photo: An upper side, or dorsal, view of a painted lady, taken by jme314. CC BY 4.0. Cropped from original.

Painted ladies are uniquely adaptable and widespread. They will lay eggs (and feed, as caterpillars) on a wide variety of host plants. They also breed throughout their migration. That means new caterpillars hatch along the migration routes. That’s helped them thrive on every continent except Antarctica and Australia. (Did you ever have caterpillars in your classroom in school? They were probably painted ladies. Their adaptability makes them easy to raise and study.)

Photo: A painted lady caterpillar resting on a leaf. Taken by emilyk04. CC BY 4.0. Cropped and rotated from original.

Cabbage White: The Bad Rap

The innocuous-looking cabbage white butterfly caterpillar is the foe of vegetable gardeners all summer long. The bright green caterpillar blends in with leaves. That makes it hard to find as it munches hungrily on the leaves of cruciferous plants (kale, cabbage, brussels sprouts, and their relatives). They can decimate a garden crop, even boring into the center of the plant to feed on new sprouts.

Photo: A cabbage white caterpillar on a leaf, with evidence of its appetite. Taken by Darien Harris. CC BY 4.0. Cropped from original.

The undersides of adult butterflies’ wings are usually white, with a yellow or greenish dusting on top. Black-brown spots and shading also adorn the upper side of their wings. The wingspan ranges from one to two inches. Though a highly competitive introduced species, the adult butterfly is still an important pollinator. If possible, encourage the adults to lay eggs outside of your garden using one of these strategies:

• Netting around cruciferous plants
• Planting nasturtiums alongside or nearby as ‘companions.’ Nasturtiums are also host plants for the cabbage white.

Photo: A cabbage white butterfly just above a cabbage plant.

Harvester: The Carnivore

If you have sharp eyes, you may be lucky enough to spot a unique butterfly this summer. The harvester is North America’s only carnivorous butterfly species. The caterpillar feeds exclusively on aphids. Even the adults will forgo flowers to drink honeydew (the substance secreted by aphids after feeding on plant sap).

Photo: A harvester caterpillar in Maine. Taken by Elise Smorsczewski. CC BY 4.0. Cropped from original.

The harvester’s wings grow to just over an inch, with an orange-brown background and black spots on the upper side. The underside has small, faint white circles. The carnivorous caterpillar is fuzzy with white and orange-brown stripes and small black spots.

Photo: The underside of a harvester butterfly. Taken by Bernie Paquette. CC BY 4.0. Cropped from original.

Help uncover the mysteries of Vermont’s butterfly population

For years, butterflies were a mystery in Vermont. Beautiful, and appreciated, but largely unstudied. In 2002, the Vermont Center for Ecostudies (VCE) launched the first Vermont Butterfly Atlas. Volunteer community scientists documented the number and locations of butterflies across Vermont.

Twenty years later, VCE is updating that landmark effort. The second Vermont Butterfly Atlas will capture how Vermont’s butterfly populations have changed. VCE hopes to understand whether conservation efforts can help protect vulnerable species. We are teaming up with VCE to encourage participation in the second Vermont Butterfly Atlas.

Photo: A close-up of the Canadian tiger swallowtail’s hind wings.