The black swallowtail (Papilio polyxenes) is an attractive butterfly that has a unique wing silhouette and remarkable markings.
If you wanna know how to distinguish the male black swallowtail from the female black swallowtail (they are both common visitors in many gardens), then take a closer look at the black swallowtail’s wings.
Typically the female black swallowtail will have more blue and less yellow on its wings and with the male black swallowtail, vice versa.
To learn more about the male and female black swallowtails and their actions in a garden, this short read will cover most of the basics and some natural ways to attract black swallowtails and other butterflies to your backyard.
About the Black Swallowtail
The black swallowtail is one of the lovely aspects of a North American summer.
Also called the American swallowtail (as opposed to the British Swallowtail butterfly Papilio machaon britannicus), it can be found from southern Canada all the way down to the higher parts of South America.
The black swallowtail is a prairie butterfly and is generally located in fields, meadows and other spacious areas with nectar-rich wildflowers, including backyards.
It is definitely an all-American butterfly and is the designated state butterfly for Oklahoma.
Black Swallowtail Male Versus Female
Identifying male black swallowtails versus female black swallowtails will be easy, since you will know the overall size and makeup of black swallowtails.
The following bullets summarize the key differences:
- Female black swallowtails tend to be comparatively larger
- The upper wing surface two rows of yellow spots are larger and brighter in males, and smaller and fainter in females.
- The blue area of the lower wing appears bolder in females
- The female appearance can mimic another related butterfly species (the pipevine swallowtail [battus philenor]), which is poisonous.
The average wingspan of the black swallowtail is 6.5 – 10.6 cm (2.5 – 4.2 in).
Both the male and female black swallowtail butterflies have:
- a red eyespot (w/ central black dot) on the hindwing
- a single yellow dot on the front edge of their wings
- identical ventral wing patterns, with pale yellow spots and bright orange dots with areas of light blue.
- and of course, the signature elongated swallows tail.
The ventral wing color pattern also mimics toxic relatives (Batesian mimicry).
Interesting Fact: Both sexes will actually have the mimicking wing design exposed as they rest with their wings closed, to be able to deter predators.
Black Swallowtail Butterfly Garden Activity
If you’re aware of the behaviours of black swallowtail, you’ll be able to prepare your garden to be inviting to black swallowtail.
Black swallowtails are territorial and the male swallowtail will want to establish their territory and patrol their area looking for a female to visit.
When two male swallowtails encounter one another, they can be aggressive and a male that crosses into a patrolled territory will be challenged and chased away.
As competition for females is high as black swallowtail has an extremely high male-to-female ratio of about 1:4 males competing for each female!
The black swallowtail males feed on nectar from flowers from standard American flower species:
- Zinnias.
- Verbena.
- Milkweed.
They also get minerals and salts from wet ground.
Swallowtails spend a good amount of time resting in sheltered areas; they will also bask in the sun to warm their body.
If they overheat swallowing tails lower their bodies and shade their abdomen under their wings.
Lifecycle of the Black Swallowtail Butterfly
Black swallowtail butterflies start off their life cycle as eggs and are deposited by female black swallowtail butterflies generally one egg at a time on host plants.
Most black swallowtail butterfly eggs will hatch, in about 10 days.
A common host plant of the caterpillar that hatches is parsley so they are commonly known as parsley caterpillars.
They are gluttonous eaters of parsley and other common herbs as they go through both larval and pupal stages. They take the toxins from these plants and store them for their adult life so that they taste bad to would-be predators.
Other host plants are:
- Dill
- Fennel
- Celery
- Carrot
The parsley caterpillar lives through a larval stage that will last up to 30 days and then pupal stages that is usually dependent on environmental conditions which can last up to 18 days.
The chrysalisSwallowtail formed by the caterpillar is usually green or brown to camouflage it in its environment.
Adult butterflies typically emerge in the Spring with males typically emerging first so that they may claim their territory.
Having Black Swallowtail Butterflies Visit Your Garden
Black swallowtails provide a beautiful display and can be an appreciated pollinator in most yards.
The parsley caterpillar can be a “pest” to some gardeners and growers because it loves parsley and other herbs.
These caterpillars will quickly and voraciously eat entire plants.
Fortunately, they are not very abundant, and we don’t need to control them with pesticides that would kill not only the black swallowtail, but other beneficial pollinators too.
Gardeners wanting to protect their plants merely have to pick out and relocate or kill the individual caterpillar.
Laws Of Nature: black swallowtails and parsley caterpillars have natural predators that keep them in check so they don’t ever become true pests.
Consider Welcoming Black Swallowtail Butterflies to Your Garden
If you want to admire this American beauty from your back porch, you can help the black swallowtail butterfly settle in by planting host plant species, such as parsley or dill, in your garden.
If you grow carrots for them – it’ll be a win-win situation; you and the caterpillars will have something to nibble!
The black swallowtail caterpillars will benefit gardeners who tolerate the parsley caterpillar, because their bad taste will repel birds and other unacceptable predators that will also cause damage to your other crops.
Final Words
Planting wildflower or Zinnia seeds provides adult butterflies with an abundance of nectar to feed on all summer.
Not only do you benefit your garden by attracting pollinators like the black swallowtail, but you also benefit your community garden as well.