Black Swallowtail Butterfly – Species Profile & Facts
The Black Swallowtail (Papilio polyxenes) is a very recognizable North American butterfly displaying slightly different appearances based on the species but retaining much of the original color and patterns. This species is notorious for its preference for farmlands, but you can also spot it in urban areas, so long as it can find the flowers it needs.
The Black Swallowtail is one of the most interesting species of butterflies and among the most beautiful.
Today we will discuss its lifecycle, feeding behavior, and other aspects that recommend this species as one of the most popular.
How to Recognize a Black Swallowtail Butterfly?
As the name suggests, this species appears in black and black variations, along with colors like yellow, red, and blue, the latter regarding females. The butterfly’s forewings are slightly arched towards the hindwings and display two rows of yellow cones and dots on its bottom margin.
An interesting aspect of the Black Swallowtail is that males and females showcase different colors. To an untrained eye, they belong to different species.
The male is intense black with yellow dots and 2 red ‘eyes’ on its hindwings. Males may display various shades of black, but they will remain within the same color range.
The female is a combination of dark blue and grey and light blue on its hindwings. The wing dots are usually either light yellow or white. The female Black Swallowtail is also larger than the male and will display the same red bullseye on its hindwings, just slightly smaller.
What Does a Black Swallowtail Butterfly Caterpillar Looks Like?
The Black Swallowtail’s caterpillar shares a lot of visual cues with 2 other butterfly species, the Monarch (Danaus plexippus) and the Queen (Danaus gillipus). All 3 caterpillars display the same segmented body, sharing the black, white, and yellow stripped pattern.
Upon a close inspection, however, the differences begin to stand out. Here are the unique visual indicators that are specific to each species, so you can tell the difference.
- Queen – The Queen is the easiest one to identify. The caterpillar has a long and slim body with 3 pairs of antennae-like horns on its back. The first pair is on its nape, the second one is on the middle of its thorax, and the other is on its bottom. This caterpillar also displays black bands traversing its body, each containing 2 yellow dots on the back. This gives the Queen a somewhat alien but elegant look that you rarely get to see in other species.
- Monarch – The Monarch caterpillar showcases black, white, and yellow bands in sandwiches of 3, from head to tail. The Monarch also has those black thorns on its back, but only 2 pairs, one on its upper thorax and one on its rear end. The thorax ones are larger, whereas the bottom ones are tiny by comparison. This caterpillar also has a long and slender body, similar to that of the Queen
- Black Swallowtail – The Black Swallowtail caterpillar is bulkier in appearance and has a light green body with black and yellow band markings. Unlike the previous 2, this caterpillar displays black spots on its legs and abdomen and yellow lumps on both sides of its body. It lacks the trademark horns of the other 2 species, replacing them with tiny spines, 2 on each body segment, from head to tail.
These 3 may look like they belong to the same species, but only at a shallow look. A closer inspection will reveal all the key differences between them.
How Big Does a Black Swallowtail Butterfly Get?
The Black Swallowtail can reach a wingspan of 2.7 to 3.3 inches, with the latter value describing the female since it grows larger than the male. There are few differences between the various species in terms of size since all swallowtails live in identical environmental conditions.
Where do Black Swallowtail Butterflies Live?
The Black Swallowtail’s territory is identical to that of the Monarch. You can spot this species all the way from Southern Canada to South America, with only isolated sightings beyond these lines. This geographical limitation speaks volumes about the Swallowtail’s preference for tropical and temperate areas.
You can find the Swallowtail in a variety of biomes, including marshes, parks, deserts, and even mountainous areas, at low altitudes. The butterfly prefers warmer climates, aiding in its reproduction and supporting the flora that its species is fond of.
What do Black Swallowtail Butterflies Eat?
As is the case with all butterfly species, the Swallowtail’s diet differs based on its developmental phase. In this sense, we have:
- Larva – The caterpillar will consume several garden plants like Queen Anne’s Lace, fennel, dill, and parsley. They prefer a variety of plants in the Apiaceae family, which contain more than 80 different species. Just like the pipevine Swallowtail, this caterpillar is also toxic, albeit not at the same degree. The Black Swallowtail larva extracts toxins from the plants it consumes to become bitter and increase its survival rate. Predator birds will usually avoid the caterpillar because of this.
- Adult – The adult butterfly is fond of sweets and will consume a variety of flowers in the wild, including milkweed, red clover, zinnias, purple verbena, and thistle. The Black Swallowtail consumes plants in the Asclepias genus (milkweed) is a good indicator of the butterfly’s defense mechanism. Milkweed got its name from the milk and stringy substance that the plant will produce when its cells sustain mechanical damage. This substance contains cardiac glycosides or cardenolides, which are toxic to multiple animals, including humans. Not the Black Swallowtail, however, which can consume the plant’s nectar without being affected. However, unlike the pipevine Swallowtail, the Black Swallowtail doesn’t extract cardenolides, which means that the adult butterfly is palatable.
What Plants Attract Black Swallowtail Butterfly?
The adult butterfly prefers anything related to the Asclepias genus. This genus comprises more than 200 plant species thriving in various environments, primarily in America and Africa. An interesting aspect about this genus is that the plants produce impressively complex flowers, rivaling orchids in beauty and intricacy.
Milkweeds are especially interesting thanks to the pollination mechanism that the Black Swallowtail is a part of. The plant keeps the pollen in special sacs instead of the usual tetrads most commonly seen in other species. These sacs are typically hidden in subtle slits formed by the plant’s distinct anthers.
These sacs will attach to the visiting insect’s legs, since they’re sticky, and the insect will have to rip them from their place so it can fly away. This mechanism only works for slightly larger and more powerful insects. Smaller ones will simply remain trapped and they will eventually die.
The Black Swallowtail, along with other butterfly species like the Monarch, plays its role in the pollination process, but they aren’t that great at the job. That’s because they use their long proboscis to obtain the nectar, whereas hymenopterans like wasps and bees go inside the flower to feed.
How do Black Swallowtail Butterflies Reproduce?
The butterfly’s reproductive cycle begins with the mating process is may last around an hour. The male will scan for females in open areas or from nearby hilltops, giving them a birds’ eye view on its surrounding territory. The male Black Swallowtail guards a territory of approximately 230 square feet and will patrol it several times during the day.
As soon as the male spots the female, it will pursue and attach to it in mid-flight. They will land in a safe area and remain attached for the following 30 to 45 minutes on average. Soon after mating, the female flies away to look for a good spot to lay its eggs.
The female Black Swallowtail may mate with other males along the way, to ensure that its eggs have been fertilized. She will lay around 40 to 50 eggs per day for several days, up to 450 per season.
Following the mating process, the butterfly’s reproductive cycle undergoes the 4 trademark phases:
- Egg – The eggs are either white or milky and will hatch around 10 to 14 days later, depending on the environmental conditions.
- Larva – The newly born larvae are tiny when they enclose and look nothing like the adult caterpillars you’re used to seeing. The Black Swallowtail caterpillar will undergo the typical 5 molts, during which the larvae’s size and appearance will change dramatically. The newborn is almost completely black with prominent spins on its back. The larva will then change appearance, becoming reddish or orange with the second and third molt, with visible band pattern all over its body. The fourth and fifth molt transform the larva with that iconic stripped look and bulgy head. The larva will begin to feed shortly after birth, preferring plants in the Umbelliferae family like celery, parsley, carrots, or dill.
- Pupa – For seasonal Black Swallowtails, the pupa phase may last around 18 days, with some variations. The overwintering Swallowtail pupae will last several months, with the adult spawning in spring, when the cold season is over. The pupa is either green or brownish in color with a distinct oval shape and segmented in the lower half.
- Adult – The adult will emerge in the spring and immediately begin to look for food. They will live 14 days on average, from mid-May to late June, depending how soon they can find a compatible mate.
Where do Black Swallowtail Butterflies Lay Their Eggs?
All Black Swallowtail prefers to lay its eggs on plants in the Umbelliferae family. These will serve as food for the emerging caterpillars who will spend all their time consuming calories and undergoing molting.
The female will simply lay the eggs and leave, providing no maternal care to the future hatchling.
Are Black Swallowtail Butterflies Rare?
The Black Swallowtail is spread throughout America, mostly around the eastern and western regions and south Canada. This species thrive in areas providing optimal climatic conditions and an abundance of food, but are almost absent in regions like Florida Keys.
That’s because that region lacks some of the butterfly’s main host plants, mainly carrots. Other than that, the Black Swallowtail is doing just fine in most of its native areas.
Is the Black Swallowtail Butterfly Endangered?
Most Black Swallowtail species are not endangered anywhere in the world. There is one, however, that made it on the endangered list, and that’s the Schaus Swallowtail. This species suffers heavily due to deforestation and specific human activities affecting its habitat and disrupting its life cycle.
You can mostly find the Schaus in the Biscayne National Park and only in limited numbers. Over the past 6 years, only around 500 Schaus Swallowtails have been observed in the Park, so there are still no telling how many live specimens there are.
Other than that, the rest of the Swallowtail species thrive in various biomes throughout America, Europe, Africa, and Asia.
How Long do Black Swallowtail Butterflies Live?
The adult Black Swallowtail will typically live around 14 days, sometimes more, depending on the available environmental conditions. The butterfly’s entire lifespan, including the entirety of its lifecycle, can exceed 6 months for overwintering species.
The Black Swallowtail lives longer than other butterflies thanks to its defensive mechanisms via Mullerian and Batesian mimicry, which we will discuss in the following paragraphs.
What is the Meaning of Black Swallowtail Butterfly?
The name of Black Swallowtail doesn’t mean anything in particular. It’s just a general descriptor of the butterfly’s appearance. Its Latin name, Papilio polyxenes, however, has Greek flavors to it. The name comes from princess Polyxena, daughter of King Priam and Queen Hecuba of Troy.
The princess’s legend varies, some versions claiming that she committed suicide after Achilles died, as she contributed to his death. Other versions point towards a sacrifice, as the Greeks killed her on Achilles’s tomb to avenge his death.
Either way, it’s a tragic story that transpires quite well in the Black Swallowtails funeral, yet beautiful appearance.
Is the Black Swallowtail Butterfly Poisonous?
Yes, and no. The Black Swallowtail displays an intricate defensive mechanism that differs from larvae to adults as follows:
The Black Swallowtail caterpillars resemble the Monarch larvae and share their toxic content. Like the latter, Black Swallowtail caterpillars consume toxic plants and extract toxins to enhance their defensive mechanisms. They taste bitter, which makes them unpalatable to most predatorial birds. As a plus, this species also possesses an osmeterium.
This is a tongue-like yellow or orange forked organ situated under the prothoracic segment. It’s basically above the caterpillar’s head, hidden in the nape segment. The osmeterium is similar to a fleshy snake tongue and contains various toxins, depending on the species. These may include esters, aliphatic acids, or monoterpene hydrocarbons, among other substances.
These substances release a powerful unpleasant odor that functions as an olfactory repellent against many predators, including birds, lizards, and amphibians.
These factors can easily rank the Black Swallowtail caterpillar as a Mullerian mimic (mimicking other species’ appearance and other defensive mechanisms).
– Adult butterfly
Unlike the larva, the adult Black Swallowtail is palatable to predators since it no longer ingests toxins. That being said, the adult Black Swallowtail butterfly has developed other, more ingenious self-defense mechanisms.
One of them is the resemblance to the pipevine Swallowtail. This is a poisonous species where both the larvae and the adults share the same awful taste. The Black Swallowtail displays color patterns similar to the pipevine Swallowtail but doesn’t share the species’ poisonous content.
This ranks the adult butterfly as a Batesian mimic (only sharing visual cues with other species without taking any other defense mechanisms).
Another interesting mechanism can be seen in males. The male Black Swallowtail butterfly mimics the female’s color pattern since it’s the female that mimics the pipevine Swallowtail. This may lead to confusion when trying to distinguish male from female Swallowtails.
As a plus, males who mimic female patterns better have a higher survival rate than those that don’t.
The Black Swallowtail consists of multiple species spread across the Globe. The American version is one of the most adaptable thanks to its mimicry and overwintering behavior. It is a beautiful, adaptable, and resilient butterfly species that’s here to stay.
You can even keep the butterfly as a pet, provided you ensure optimal living conditions. If that sounds like too much work, simply fill your garden with plants that butterflies prioritize as host plants. If you want to have caterpillars as well, focus on the Umbelliferae family.
If you only want adult butterflies, focus on phlox, milkweed, zinnias, and other similar.