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Western Tiger Swallowtail (Papilio rutulus)


Western Tiger Swallowtail

The Western Tiger Swallowtail are butterflies that belong to the popular ‘swallowtail’ group that is well-known for their vibrant coloration and characteristic triangular wings. These are active butterflies that prefer sunny habitats and can also be seen puddling in the mud, flocking together in large numbers. This species can best be located in the summer, especially between June and July.

Scientific Classification

  • Family: Papilionidae
  • Genus: Papilio
  • Scientific Name: Papilio rutulus

Description and Identification


Western Tiger Swallowtail Caterpillar
Western Tiger Swallowtail Butterfly Caterpillar

For camouflage, the young caterpillars, as they hatch out, strangely resemble bird droppings. As they begin to molt, they turn bright green in color, with large, yellow eyespot marks studded with black and blue pupils. They usually hatch out around four days after the eggs are laid. They molt five times and can reach a maximum length of 5 cm.


Western Tiger Swallowtail Chrysalis

The chrysalis is light brown with golden spots on the back, and about ten black spines protruding from the ventral side. The thorax or mid portion is distinctly curved, with the antennae having multiple short black spines.

Adult Butterfly

Sexual Dimorphism: Not present

Color and Appearance: The wings have a characteristic triangular shape with protrusions in the form of swords at the bottom of the hind wings. When the wings are open, they show a white to pale yellowish white base with random black stripes and bands that run vertically. The hind wings consist of two blue spots at the inner corner of the inner margin (right the point where the abdomen ends). When the wings are closed, each of the ventral sides of the wings displays similar stripe patterns, while the rounded borders of the secondary wings have a cyan blue hue that runs parallel to the margin.

Papilio rutulus
Western Tiger Swallowtail Butterfly

Average wingspan: 2¾ – 4 inches (7 – 10 cm)

Flight pattern: Gliding, with fewer flaps


Western Tiger Swallowtail Eggs

Dark green, glossy, and spherical; up to a hundred eggs in total are laid singly on the undersides of the leaves of host plants

Quick Facts

Distribution Western parts of the United States and the southern regions of British Columbia
Habitat Common in suburban gardens, also found in meadows, streamsides, and woodland edges
Lifespan of adults 6-14 days
Host plants A wide variety of host plants including willows, aspens, ashes, poplars, alders, and cottonwood
Adult diet Flower nectar especially those of thistles, zinnia, abelia, yerba santa, and California buckeye

Did You Know?

Among all the large butterflies, it is one of the most common, which the butterfly enthusiasts are likely to see in and around the urban areas.

Western Tiger Swallowtail Pictures
Western Tiger Swallowtail Images
Western Tiger Swallowtail Host Plant

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Scientific Classification

  • Family: Papilionidae
  • Genus: Papilio
  • Scientific Name: Papilio rutulus
Published by Avatar on January 30, 2019.
Last Updated: December 20, 2022. ✅ Verified by: Butterfly Team