The Two-tailed Swallowtail Butterfly is the state insect of Arizona in the United States. It is a large butterfly with a wingspan that can reach 15 cm (around 6 inches). A female lays a single, yellow spherical egg on the leaf of a host plant. The caterpillar creates a retreat between feedings by curling a leaf using its silk to secure the closed edges.
This caterpillar changes colors drastically as it matures and it can grow quite long. A young caterpillar is bumpy and mottled brown with a white saddle on its 'back', a look that resembles inedible bird droppings. The area behind its head is already bulging at this stage, and it might be mistaken for the actual head. As it grows, the caterpillar becomes quite smooth and turns leafy green. Some body segments are ringed with small, almost iridescent, blue dots. A yellow collar around the 'neck' eventually adds a bold black band just under it. The bulge has two eyespots with blue pupils, which gives it a more snake-like appearance. To add to the serpentine mimicry, the caterpillar can extend an appendage that looks like a forked tongue. It is called an osmeterium and is displayed when the larva feels threatened. It can startle a predator and emits an odor that may deter an attack. The late stage appearance for this caterpillar is brown. When the weather becomes colder, the caterpillar moves to the soil and overwinters in its chrysalis.©CaterpillarIdentification.org
The map above showcases (in blue) the states and territories of North America where the Two-tailed Swallowtail Caterpillar may be found (but is not limited to). This sort of data can be useful in seeing concentrations of a particular species over the continent as well as revealing possible migratory patterns over a species' given lifespan. Some species are naturally confined by environment, weather, mating habits, food resources and the like while others see widespread expansion across most, or all, of North America.*NOTE: States/Territories shown above are a general indicator of areas inhabited by the Two-tailed Swallowtail Caterpillar. Insects generally go where they please, typically driven by diet, environmental changes, and / or mating habits.
