Backyard Ecology Creating Space for Pollinators and Wildlife
Creating Space for Pollinators and Wildlife

Question Mark Butterfly: One of our earliest flying butterflies

The question mark butterfly (Polygonia interrogationis) breaks many of the stereotypes that we usually place on butterflies. In some places, you can find it flying on warm days in late February or early March. If you do see one fly by, pay close attention to where it lands. They have amazing camouflage that allows them to virtually disappear on a tree trunk or bare spot on the ground. Question mark butterflies might not be the flashiest or most well-known butterflies, but they can be very interesting to learn about and watch.

Where to find the question mark butterfly

Question mark butterflies can be found throughout the eastern U.S. and parts of Canada. They are most often found in open woods or near the edges of woods. Within human dominated landscapes, question mark butterflies can be found in parks or older subdivisions where there are plenty of trees. They can also be found along woody fence rows. Question mark butterflies are particularly fond of moist areas or areas near a creek or other body of water.

Look at the hind wing. See the curved white line with the white dot next to it? That’s the “question mark” that gives this butterfly its name. It is only visible when the wings are closed or mostly closed so that you can see the underside of the wing. Photo credit: Laurie Sheppard / USFWS, public domain

What does it look like?

Adult

The question mark butterfly is a medium sized butterfly. Its wingspan (when the wings are open) is typically between 2 inches and 2.5 inches wide. That’s roughly the diameter of a coke can, with the top of the can being closer to 2 inches in diameter and the middle of the can being closer to 2.5 inches in diameter.

Question mark butterflies have very angular shaped wings. (The genus Polygonia references this angular nature. Poly means many and gonia means angles.) Many people describe the wing shape as looking like angel wings. In fact, angelwings is sometimes used as a generic common name for members of this genus. To me, the edges of the wings look like the wavy edges of a leaf, especially when the wings are closed.

Whether the wings are open or closed makes a big difference in what this butterfly looks like. It would be very easy to think you were looking at two different types of butterfly depending on the position of the wings. When the wings are closed, they are light brown. In this position, they resemble a dead leaf and can almost disappear if they are sitting on a tree trunk or bare spot of dirt.

When the wings are open, you may see one of two patterns depending on the time of year. Both patterns include a general reddish orange to tannish orange background color with dark brown spots. The summer form, which is generally seen from May to September, has a dark brown or black wash that can cover most of the lower / hind wings. The winter form, which generally starts to appear in August, lacks the dark wash of color on the hind wings and instead just has the orangish background color.

The question mark butterfly also has two tails. The tails are similar to those of the more familiar swallowtail butterflies, but not nearly as long. The tails on the winter form are longer than those on the summer form.

Caterpillar

The question mark caterpillar has a black body and a reddish-brown head. The black body is often covered with yellow, orange, or red stripes that run the length of the body and little white spots. Sometimes the stripes are so dense that it is hard to see the black underneath.

Question mark caterpillars are also spiney. The spines vary in color and can be yellow, orange, red, or black. Each spine is branched and reminds me of honey locust thorns.

The summer form of the question mark butterfly has a dark brown or black wash covering most of the hind / lower wing when the wings are open. Photo credit: Dr. Thomas G. Barnes / USFWS, public domain

Basic biology and life history of the question mark butterfly

Question mark butterflies have two generations per year. The first generation is the summer form and typically flies between May and September. Male question mark butterflies will perch on leaves or on tree trunks to watch for passing females. They will often fly out to investigate other insects, birds, or other critters (including us) that pass close by.

After mating, the female will lay her eggs on the underside of leaves. The eggs are laid either singly or in stacks of up to six eggs. Many butterflies lay their eggs on their host plants, but not the female question mark butterfly. She typically lays her eggs on non-host plants. Question mark caterpillars must find their own food after they hatch.

The second generation is the winter form and typically starts appearing around August. Question mark butterflies overwinter as adults in the winter form. Some question mark butterflies will stay where they are at and hibernate in tree cracks, under peeling bark, or in wooden structures. These butterflies may be seen flying on warm winter days, especially in late winter and early spring.

Other question mark butterflies will migrate to more southern regions for the winter. It is unknown how far south the migratory question mark butterflies go. We also don’t know if they congregate in some unidentified location or stay dispersed across the landscape. Each spring, there is always some dispersal or migration back into more northern regions.

The winter form of the question mark butterfly lacks the dark brown / black wash on the hind wing when the wings are open. Also note the “dash” on the upper wings. (The arrow is pointing to the dash on the left wing.) The dash is what distinguishes the question mark butterfly from the eastern comma when the wings are open. Photo credit: Judy Gallagher, cc-by 2.0

Dietary preferences of the question mark butterfly

Adults

The dietary preferences of the question mark butterfly are not what we typically think of for butterflies. Very rarely will you see them drinking nectar. Question mark butterflies primarily feed on tree sap, rotting fruit, carcasses, and scat. They also puddle and will suck nutrients from damp soil.

Caterpillars

Host plants for question mark caterpillars include elms (Ulmus sp.), hackberries and sugarberries (Celtis sp.), Japanese hop (Humulus japonicus), nettles (Urtica sp.), and false nettle (Boehmeria cylindrica).

How to identify the question mark butterfly

When trying to determine whether a butterfly is a question mark butterfly, the very first thing I do is look at the shape of the wings. If the edges of the wings have that angular / angel wing / wavy leaf shape, then you can immediately rule out most of the orangish butterflies of roughly the same size. Likewise, if the edges of the wings do not have that shape, then you can rule out the question mark butterfly.

The butterfly that is most likely to be confused with the question mark butterfly is the eastern comma (Polygonia comma). They look very similar and can be challenging to distinguish. I find a pair of binoculars very helpful, because they let me see details from further away.

Question mark caterpillars have reddish brown heads, black bodies with thin stripes running the length of the body, white spots, and branched spines. Photo credit: Judy Gallagher, cc-by 2.0

Both question mark butterflies and eastern commas will often sit with their wings closed. When their wings are closed is when you can see the marks that give each species its name. About midway down the lower / hind wing, you’ll see a small, thin, curved, white line on both species. Question mark butterflies will tend to have a small white dot next to that curved white line, while eastern commas lack the dot. Evidently, someone thought that the curved white line looked like a comma, and adding a dot made it look like a question mark.

The white “question mark” or “comma” is only visible on the underside of the wings. Question mark butterflies and eastern commas look very similar with their wings open as well. When the wings are open, look towards the top of the upper wing. Question mark butterflies have a dark brown dash, while commas do not.

There are a few other distinguishing characteristics between the question mark butterfly and the eastern comma. Question mark butterflies tend to be slightly larger, have slower wingbeats, and slightly longer tails. However, you have to be pretty familiar with both species before you are likely to notice these differences. There are many times when I will simply say “that was a punctuation butterfly,” because I didn’t get a good enough look to be confident as to which one it was.

Attracting and observing the question mark butterfly

You will have the most success attracting question mark butterflies if you live in or near an area with trees. Question mark butterflies rarely go to flowers. Put out watermelon rinds or over ripe fruit to attract adult question mark butterflies to your yard. Question mark butterflies will also puddle, so providing small mud puddles or areas with moist soil can help attract them.

Like other butterfly species, planting host plants, and thus providing baby food for the caterpillars, is another way to attract question mark butterflies. As a side note, false nettle lacks the stinging hairs associated with stinging nettle, so can be safely mixed into a pollinator garden. False nettle is wind pollinated and doesn’t have “pretty flowers,” so you’ll probably want to tuck it behind showier flowers if you decide to incorporate it into your garden.

Summary

When we think about butterflies, we often also think of flowers and open fields. But the question mark butterfly breaks those stereotypes. It prefers open woods to open fields. It rarely goes to flowers and prefers tree sap, rotted fruit, carrion, or scat. When it comes to all the things we think a butterfly should do, the question mark butterfly is kind of a rebel. However, if you have the right habitat and provide the right food sources, then the question mark butterfly can be an interesting species to attract to your yard.


Backyard Ecology: Creating Space for Pollinators and Wildlife
Nature isn’t just “out there.” It’s all around us, including right outside our doors. Hi, my name is Shannon Trimboli, and I am the host of Backyard Ecology. I live in southcentral Kentucky and am a wildlife biologist, educator, author, beekeeper, and owner of a nursery specializing in plants for pollinators and wildlife conservation. I started Backyard Ecology as a way to share my love of exploring nature and learning about different plants and animals. I invite you to join me as we ignite our curiosity and natural wonder, explore our yards and communities, and improve our local pollinator and wildlife habitat. Learn more or subscribe to my email list at www.backyardecology.net.

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