Have you ever been captivated by a vibrant orange butterfly gracefully fluttering by, and paused to wonder if it was the iconic monarch? You’re definitely not alone! The monarch butterfly is a truly beloved and easily recognized insect across North America. However, nature can be tricky, and there are several look-alike species that can easily confuse even seasoned nature enthusiasts.
Being able to correctly identify a monarch butterfly is more than just a fun skill for those who love the outdoors—it’s actually vital for monarch conservation efforts. Monarchs are crucial native pollinators playing an essential role in the North American ecosystem. Sadly, their populations are facing a staggering decline across the continent. Citizen science initiatives, such as Monarch Watch, rely on observational data from people like you to understand monarch population status. That’s why we’ve developed this comprehensive monarch butterfly identification guide and quiz. It’s designed to help you confidently distinguish the monarch butterfly from similar-looking butterflies. We’ll explore the differences in adult butterflies, caterpillars, and even the plants they depend on. So, whether you are a beginner naturalist or a dedicated butterfly enthusiast, keep reading and get ready to become a true Monarch Maven with our monarch butterfly identification guide quiz!
Meet the Monarch Butterfly
Photo credit: Edward Episcopo (left), Michael Harvey (right)
There are six subspecies of monarch butterfly found globally, but in North America, you’ll primarily find Danaus plexippus plexippus. A second subspecies, Danaus plexippus megalippe, which is non-migratory, can also be found in Florida and Georgia southward. Visually, these subspecies appear identical to the untrained eye.
These magnificent butterflies are truly a sight to behold. Their wings are a vibrant orange, adorned with intricate black veins and a distinctive black border dotted with bright white spots. This striking coloration isn’t just for beauty; it serves as a powerful warning signal to potential predators. Thanks to toxins they accumulate from their milkweed host plant, monarchs are unpalatable and even poisonous to many animals.
Monarch butterflies are characterized by their distinctly black bodies speckled with white. They are also relatively large butterflies, with wingspans that can reach up to 5 inches.
Adult monarch butterflies exhibit sexual dimorphism, meaning males and females have different appearances. Males are easily identified by two prominent black spots, one on each hind wing. These spots release pheromones designed to attract females for mating. Females, in contrast, generally have a darker shade of orange and exhibit thicker black veining on their wings.
Monarch Caterpillars
Photo credit: Don Chernoff
The monarch caterpillar is just as captivating as the adult butterfly. It is strikingly patterned with bright bands of yellow, black, and white. Like the adult coloration, these colors serve as a warning to predators. A unique feature of monarch caterpillars, distinguishing them from some other caterpillar species, is that they possess two pairs of antennae-like tentacles, with one pair located at each end of their body. Monarch caterpillars develop through five stages called “instars,” and each instar can look quite different from the others.
First Instar: At less than a quarter of an inch long, the first instar caterpillar is quite small and mostly translucent in appearance, with faint yellowish-white bands. In this initial stage, the caterpillar’s first meal is its own eggshell, after which it begins to feed on milkweed leaves.
Second Instar: Slightly larger than the first instar, reaching about one-third of an inch in length. The yellow bands become more noticeable and the caterpillar starts to develop more vibrant coloration. During this stage, the caterpillar is a voracious eater of milkweed leaves, typically starting at the edges of the leaves.
Third Instar: Growing to approximately half an inch in length, the third instar caterpillar shows more pronounced bands of black, yellow, and white, making its coloration more distinct.
Fourth Instar: Ranging from half an inch to just under 1.5 inches long, the fourth instar caterpillar exhibits deepening colors. It begins to resemble a miniature version of the final instar stage, with a head that appears less bulbous compared to previous instars.
Fifth Instar: The final larval stage, the fifth instar caterpillar can grow up to 1.75 inches long. At this stage, the caterpillar is plump and displays its most vibrant colors before pupating.
Instar identification photos courtesy of Monarch Watch.
Monarch Native Host Plants
Native milkweed is far more than just a plant; it’s the very lifeline for monarch butterflies. While adult monarchs feed on nectar from various flowers, milkweed leaves are the exclusive food source for monarch caterpillars. You will almost exclusively find monarch caterpillars feeding on a milkweed host plant. Planting native milkweed is a fantastic way to attract monarchs to your garden. By doing so, you not only provide a crucial food source for these beautiful insects but also actively contribute to monarch butterfly conservation!
Here are some native milkweed species found across North America where you might discover monarch caterpillars:
Swamp Milkweed (Asclepias incarnata)
Leaves: Characterized by their narrow and lance-shaped appearance.
Flowers: Features clusters of pink to mauve colored flowers.
Region: Commonly found in wetland habitats across most of the United States.
Common Milkweed (Asclepias syriaca)
Leaves: Broad and oval-shaped, with a distinctive soft, hairy texture.
Flowers: Produces clusters of pink to purple flowers.
Region: Prevalent in the eastern two-thirds of the U.S., but generally absent from most of Florida.
Butterfly Weed (Asclepias tuberosa)
Leaves: Narrow and lance-shaped, similar to Swamp Milkweed, but distinguished by a more vibrant green color.
Flowers: Showcases bright orange flower clusters.
Region: Thrives in well-drained soils, often found in prairies or open woodlands across most of the United States.
Showy Milkweed (Asclepias speciosa)
Leaves: Broad and covered in soft, velvety hairs, giving them a unique texture.
Flowers: Displays pink to purple flowers, similar to Common Milkweed but often more vibrant in color.
Region: Primarily located in the Western United States.
The Problem with Tropical Milkweed
Keep monarchs away from tropical milkweed!
Tropical milkweed, while it might seem like a helpful plant, can actually be detrimental to monarch butterflies. Despite being used in gardens to attract monarchs, this non-native species poses significant risks. Tropical milkweed is a perennial plant that disrupts the natural spring and fall migrations of monarch butterflies. It can also unfortunately harbor a debilitating and often fatal protozoan parasite that infects monarchs. To learn more, check out the NWF’s Supporting Picky Eaters panel discussion with experts.
Tropical Milkweed (Asclepias curassavica)
Leaves: Narrow and lance-shaped, resembling Butterfly Weed in leaf shape.
Flowers: Features bright red or orange flowers with a distinctive yellow center.
Region: Not native to North America, but frequently found in ornamental gardens throughout the region.
Note: Although visually appealing, tropical milkweed is not recommended for monarch conservation efforts. It can negatively impact their natural migration patterns and lifecycle, and increase the spread of fatal diseases.
For more detailed information on how you can support monarchs, visit the NWF’s Milkweed for Monarchs page.
Similar Species
Viceroy Butterfly
The viceroy butterfly is a species that bears a striking resemblance to the monarch—and this is no accident! It was once believed that viceroys evolved to mimic the warning coloration of monarchs, a strategy known as Batesian mimicry, to deter predators without possessing toxins themselves. However, recent scientific research has revealed that viceroys are also unpalatable, suggesting a different evolutionary relationship. It is now more likely that viceroy and monarch butterflies have evolved as co-mimics, in a phenomenon called Müllerian mimicry, where both species benefit from similar warning colors.
Adult viceroy and monarch butterflies are nearly identical in color. The key distinguishing feature is that viceroys have a noticeable black line that crosses the hindwing, which is absent on monarchs. Viceroy butterflies also tend to be smaller in size compared to monarchs. Observing their flight patterns can also help differentiate them; the viceroy butterfly’s flight is generally faster and more erratic, while the monarch butterfly exhibits a distinctive, gliding flight, often described as “sailing” through the air.
Photo credit: Judy Gallagher
Unlike the boldly striped monarch caterpillar, the viceroy caterpillar employs camouflage as its primary survival strategy. It cleverly mimics bird droppings in appearance, helping it to avoid predation. This camouflage makes it quite different in appearance from monarch caterpillars. Viceroy caterpillars also lack the distinctive antennae-like tentacles seen on monarch and queen caterpillars.
Viceroy caterpillars have different host plant preferences than monarchs. They do not feed on milkweed. Instead, they prefer trees such as willow, poplar, and apple trees.
Queen Butterfly
Photo credit: Roy Niswanger
The queen butterfly is another species frequently mistaken for the monarch due to their similar orange and black coloration. Queen butterflies are primarily found in the southern regions of the United States, as well as Mexico, and Central America.
Queen butterflies are slightly smaller than monarchs, with a wingspan ranging from 2.5 to 3.5 inches. Their coloration is similar to monarchs, but the queen’s orange is typically a deeper, browner shade. Queen butterflies also lack the prominent black coloration over their wing veins that is characteristic of monarchs. However, they do have some dark black veining on the underside of their hind wings, visible when the wings are closed. To identify a queen, look for the absence of black veining on the underside of the forewing and the presence of white spots within the orange portions of the wing. Monarch butterflies only have white spots on the black parts of their wings.
Queen butterflies also have black bodies with white spots, but unlike monarchs, their abdomen is tipped with a gray-orange color. Similar to the viceroy, the queen butterfly’s flight pattern is quicker and more fluttery compared to the monarch’s characteristic glide.
Photo credit: Renee Grayson
The queen caterpillar shares numerous similarities with the monarch caterpillar, making it easy to confuse the two. Like the monarch, the queen caterpillar feeds on milkweed and features bands of yellow, black, and white. However, the queen caterpillar’s colors are often more muted or subdued in tone. Queen caterpillars are also generally smaller than monarch caterpillars. The most reliable way to differentiate these caterpillars is to count their pairs of tentacles. Monarch caterpillars have one pair at each end, while queen caterpillars have an additional third set located partway down their body.
Painted Lady Butterfly
Photo credit: Marko Kivela
The painted lady is another butterfly species that can be mistaken for the monarch, especially by beginners in butterfly watching. While not as closely resembling monarchs as the queen or viceroy, its orange coloration can sometimes lead to confusion.
Painted ladies are generally smaller than monarchs, with a wingspan of 2 to 2.9 inches. Their orange wings display more complex patterns that lack the distinct black veining seen in monarchs. The black and white spotted borders on the wings of a painted lady appear to blend into the orange, rather than having the sharply defined edges found in monarchs.
Photo credit: Dean Morley
The painted lady caterpillar is very different from monarch caterpillars. It is covered in spiky thorns, giving it a bristly appearance. Unlike monarchs, painted lady caterpillars have a broad diet that includes a variety of plants such as thistles, hollyhocks, and legumes. They will not be found feeding on milkweed.
Black Swallowtail Caterpillar
Photo credit: Vicki DeLoach
While the adult black swallowtail butterfly looks quite different from a monarch, its caterpillar stage can sometimes be confused with monarch caterpillars. The black swallowtail caterpillar features black bands with yellow markings, which can initially appear similar to monarch caterpillars at a quick glance. However, black swallowtail caterpillars also have a significant amount of green coloration.
In general, the black swallowtail caterpillar has more prominent black bands compared to the monarch caterpillar. It also has a distinctive, horn-like organ located just behind its head called an “osmeterium.” This orange or yellow forked gland can be extended when the caterpillar feels threatened and emits a foul odor to deter predators. Monarch caterpillars do not possess this feature.
Finally, the black swallowtail caterpillar prefers to feed on plants in the parsley family, such as dill and fennel, rather than milkweed.
Test Your Skills
Now that you’re equipped with the knowledge to differentiate monarch butterflies and caterpillars from their look-alikes, it’s time to test your newly acquired skills! Are you ready to prove you’re a true Monarch Maven? Take our interactive quiz to see just how well you can identify these beautiful creatures and their similar-looking counterparts. Challenge yourself, share your score with friends, and most importantly, enjoy the exciting journey of discovery in the great outdoors. Happy butterfly watching and happy quizzing with our monarch butterfly identification guide quiz!
Garden Habitats, People and Wildlife, Wildlife Facts | milkweed, monarch butterfly, monarch conservation, monarch identification, quizPublished: September 29, 2023
