Eastern Tiger Swallowtail
| Scientific Name | Papilio glaucus |
| Survival Strategy | Overwinter as a Chrysalis |
| Conservation status | Least Concern |
Spring
In May and June, the chrysalises that survive winter diapause will emerge as adult eastern tiger swallowtails. Adult swallowtails only have two things on their task list: mate and lay eggs.
Summer
In late July and August, the second brood of swallowtails takes flight as adults.
Fall
Triggered by shortening daylight, the larvae that hatched in late-summer enter diapause as a chrysalis and wait for spring.
Winter
Swallowtails overwinter as a chrysalis in a state of diapause. No adults live through the winter.
Behavior
Tree Huggers
Tiger Swallowtails are solitary animals, preferring to spend most of their life in the canopy of deciduous trees. Recently hatched larvae spend their days resting in a silken hammock attached to a leaf. At night they will begin feeding on their host plant.
Puddling (kind of gross!)
The only time swallowtails form large groups is when they engage in puddling. It is not unusual to see many butterflies crowding a wet spot on an unpaved road. A closer look will likely reveal these insects are drinking in salts and other minerals from animal dung or urine. Puddling behavior is most common in male butterflies to replace salts lost during copulation.
Physiology
Life Cycle
Eastern tiger swallowtails complete two generations (broods) in the northern portion of their range. They will go through three generations in the southern part of their range. After laying up to 250 eggs on the leaves of woody plants, the female butterfly will live for less than two weeks. The larvae (also called caterpillars) will emerge from the eggs in about 4 to 10 days. During the next three to four weeks, the larvae will go through five instars (stages separated by molts). After the 5th instar, the larvae pupate (form a chrysalis).
Over-wintering Chrysalises Hit the “Pause” Button
The larvae that experience the shortening days of late summer will enter diapause after transforming into pupae. The pupae stop developing throughout the winter and wait for increasing day length and warmer temperatures. They produce glycerol and trehalose, which act like antifreeze to protect them from freezing. These pupae emerge as the first eastern swallowtails you see in the spring.
Diet
Eastern tiger swallowtail larvae (caterpillars) feed on various host plants, including wild cherry, basswood, birch, ash, cottonwood, American mountain ash, and willow. Adults nectar on flowering plants, including apple, wild cherry and lilac, milkweed, and joe-Pye weed.
Lifespan and Mortality
Adult eastern tiger swallowtails live about 12 days.
Predators
Predators include birds, such as the sharp-shinned hawk, great-crested flycatcher, red-winged blackbird, downy woodpecker, white-breasted nuthatch, and common crows. Mammals, such as the eastern gray squirrel, raccoon, and the Virginia opossum, will not pass up the opportunity for a quick meal. Other insects, such as the bald-faced hornet and the green darner, feed on this slow-flying butterfly.
Climate Vulnerability
The ranges of the Eastern tiger swallowtail (Papilio glaucus) and the more northern Canadian tiger swallowtail (Papilio canadensis) overlap like a Venn diagram. In this shared geographic region, the two similar species mate and produce hybrids that carry both species’ genetics. Researchers used climate data and specimens collected over the last 32 years to document that this hybrid zone has moved north about 25 miles.
Never stop learning
First Nations: The Ojibwe word for butterfly is “memengwaa.” The Butterfly Dance is a traditional social dance of the Hopi nation.
Sustainable Gardening: Eastern tiger swallowtail pupae, and many other insects, overwinter in leaf litter. When we clean up our garden beds in the fall, we remove pupae, eggs, and insulation. Next fall, put down the rake and pick up a camera.
Art History: Drawings from ancient Hopi pottery include images of butterflies. A watercolor drawing of a Tiger Swallowtail by John White in 1587 is the first known North American butterfly drawing by a European.
References
I enjoyed this-Informative to read, but I don’t know where to start. Which of your posts would you recommend I read next?
I’m hoping the blog is designed to work like a menu. The blog posts highlight individual critters, with a focus on how they survive the winter. The pages take a deeper dive into more general topics that impact winter survival.
Could this be a little out of touch-could you add more examples?