Overview of the Anise Swallowtail Butterfly

The Anise swallowtail lives in western North America and is unique for its striking blue spots and broad yellow stripes on its wings.

Anise Swallowtail Butterfly Species Summary

Scientific NamePapilio zelicaon
Family NamePapilionidae
HabitatGardens, bare hills, mountains, fields, vacant lots, roadsides
RangeWestern United States
Host PlantsAnise plants, the parsley family and the citrus family
Butterfly DescriptionYellow-orange eyespot near the tail with yellow-base wings and black veins
Caterpillar DescriptionDark Brown with a white band in the middle

Butterfly Physical Description

Anise swallowtail, from the family Papilionidae, often gets mistaken for Western tiger swallowtail and Monarch. Anise swallowtails are known for bright coloration alongside the patterned wings. When those are open, the dorsal surface of the forewing is yellow with black bands on the edges, similar to hind wings.

Secondary wings have yellow/orange eyespots near the tail, with a black pupil in each “eye.” When the wings are closed, they’re almost identical observed from the vertical side, but the patterns are a bit faint. The wingspan ranges from 2 3/4 to 3 1/2 inches, making the Anise smaller than the Tiger swallowtail.

Male adults have more yellow and less blue on their wings. Females are the opposite. The pupa (chrysalis) is light brown to green. It hangs from a branch or a host plant stem, looking like another small branch growing out of the stem.

Caterpillar Physical Description

Anise swallowtail caterpillar (larvae) has 5 instars. In its first 2 instars, the caterpillar is dark brown with an irregular white band in the middle. Once fully matured, it’s usually green and black with light blue patterns.

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Why Are They Called Anise Swallowtail Butterflies?

This butterfly species has adapted to use non-native fennel, also called wild anise, as a host plant. Plus, they belong to the swallowtails, meaning they have tails shaped similarly to a bird.

How long does an anise swallowtail butterfly live?

Egg Stage4 to 10 days
Caterpillar Stage21 to 28 days
Chrysalis Stage10 to 20 days
Butterfly Stage6 to 14 days

What do anise swallowtail butterflies eat?

This butterfly prefers to lay eggs on the undersides of host plant leaves. The common host plants belong to the parsley family (Apiaceae) and citrus family (Rutaceae). Eggs and caterpillars are also found on sweet fennel (Foeniculum vulgare). Fernleaf biscuitroot (Lomatium dissectum) is another common host for Papilio zelicaon.

The most common food plants are the same as hosts — fennel, citruses, and plants from the carrot family. However, the adult’s diet is unknown so far. Anise swallowtails also eat nectar from clover, milkweed, and thistles.

Where do anise swallowtail butterflies live?

These butterflies can be found around bare hills, mountain hilltops, and fields. They also frequent human-made gardens, vacant lots, and roadsides. The Anise swallowtail is often found in low elevations.

Anise can be seen around all western parts of North America. In the US, they live in Oregon, North Dakota, California, New Mexico, and Arizona. In Canada, they are located in British Columbia.

Do Anise Swallowtail Butterflies Migrate?

Anise swallowtails stay where they are. Instead of migrating, they form chrysalis that overwinters in protected places.

Usual Behavior

The adult butterfly flies slowly but erratically. Males perch on hilltops and look for females. They perform a typical courtship display for females and tend to grab their male opponent by the legs during aerial interaction.

Female Anise butterflies mate about 3 times, and their mating frequency increases with age. Females lay eggs on host plants (leaves, flowers, and stems). Young caterpillars eat leaves, and older ones eat flowers. This species has one flight from April to July.

Common Predators

Anise swallowtails should be careful of insects, spiders, and small birds. These can attack at any stage of the butterfly’s life cycle. However, these dangers are removed if the butterflies are raised in captivity.

Are Anise Swallowtail Caterpillars Poisonous?

Unlike some other swallowtails, Anise caterpillars aren’t poisonous. This is why they have to deter predators with their appearance. If disturbed, the caterpillar will emit a foul-smelling orangey fluid.

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