The Canadian tiger swallowtail is a close relative to the Eastern tiger swallowtail. It was previously considered a sub-category of the Eastern due to their close relationship and similar ecological characteristics. However, the Canadian has its own features that can’t be mistaken for any species. Here are 5 facts about this butterfly.
Phylum: Arthropoda
Class: Insecta
Oder: Lepidoptera
Genus: Papilio
1. They look like the relative Eastern tiger swallowtails
The Canadian tiger swallowtail is commonly found in the northern United States states and is often mistaken for its close cousin, the Eastern tiger swallowtail. With an almost identical appearance, these two species were once thought to be the same. However, a study in the 1990s proved that they were not.
It can be challenging to tell the difference between the two species of tiger swallowtails, especially as both have yellow wings with black stripes. However, there are a few distinct differences between Eastern and Canadian tiger swallowtails:
– The Canadian tiger swallowtail is smaller with a wing span of 67 to 80 mm.
– The front wing of the Canadian tiger swallowtail displays an unbroken yellow marginal spot line, which contrasts the Eastern tiger swallowtail that boasts distinct, separated spots. However, the lighting conditions may cause some Canadian Tiger Swallowtails to appear to have distinct spots.
– The Canadian’s hindwings boast a blue shading on the lower margin and feature more orange and blue accents along the border. On the bottoms of both hindwings, you can see the extending black “tails”.
– Each hindwing has an orange crescent near the inner edges, which combines to form a single orange eyespot when the wings are flat.
– The dark version of the female Canadian tiger swallowtail is really rare.
2. Habitat and Range
The Canadian tiger swallowtail butterfly can be found in the northern regions of North America, stretching from central Alaska to northern New York State and northern New England. Despite the variations in temperature and habitat within its northern range, the butterfly thrives and adapts well.
The Canadian prefers open areas near forests, lightly trafficked roadsides, the boundaries of woodland, northern hardwood, evergreen-deciduous woods, and along streams.
3. Behavior
The Canadian tiger swallowtail butterfly flies from mid-May to late July, depending on location. During this period, the population is at its peak from early June to mid-July. They can be particularly plentiful in some years. This species only creates one generation during its flight period, in contrast to the Eastern Tiger Swallowtail which has 2 – 3 broods.
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The males prefer to congregate on aspen-covered hilltops and in puddles. The other behaviors of Canadian swallowtails are the same as that of other tiger swallowtail species. You can see more about tiger swallowtail butterflies’ behaviors here.
4. Diet
The tiger swallowtail caterpillar leads a solitary life and sustains itself by eating the leaves of various host plants such as black cherry, aspens, apple trees, birches, cottonwoods, and poplars. However, these larvae are not pests to thread your plants. They do not need to be controlled.
The adult butterflies consume the nectar of flowers like sweetgrass, daisy, tufted vetch, lilac, clover, and goldenrod. Their favorite flower is the common dandelion.
5. Life cycle
The life cycle of Canadian tiger swallowtail butterflies is similar to that of the other tiger swallowtail species. They mate and lay eggs. The eggs hatch and go through five developmental stages (instar). Then they undergo the pupa stage and become adults. To know more details about the life cycle of each stage of the Canadian species, you can follow our guides.
The differences between the life cycle of these tiger swallowtail species are the colors and the shape of their larvae. Because the Canadian only produce one brood that ends in August, it becomes easier to identify them in late summer and fall.
In the early stages, the caterpillar appears white and brown, resembling bird droppings and making it less noticeable to predators. As the caterpillar matures, it becomes bigger with a large head and a green body that is dotted with small yellow spots.
Canadian tiger swallowtail larvae have a yellow ‘collar’ which is not as bold and clear as the collar of Eastern larvae. On its huge head, there are two artificial eyes with a blueish tint. This characteristic gives the creature a snake-like look, which is used to frighten off predators.
The caterpillar bodies are divided into three sections: the head, the thorax, and the abdomen. The thorax, responsible for movement, bears six legs on its segments. Meanwhile, the abdomen houses the caterpillar’s organs and functions in breathing, digestion, excretion, and reproduction.
Canadian tiger swallowtail caterpillars also have as amazing self-defense systems as the Eastern swallowtail larvae. You can read the article to know the mechanism.
The caterpillar will become brown after three to four weeks and will move down from the tree leaves. It will create a brown chrysalis, generally near the ground, or in the dead leaves on the ground.
References:
- James A. Scott. The Butterflies of North America. A Natural History and Field Guide (Stanford University Press, 1986)
- https://www.butterflyidentification.com/canadian-tiger-swallowtail.htm
