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Archive - June 2019

tiger swallowtail Papilio glaucus

What is a Tiger Swallowtail?
A tiger swallowtail is a type of butterfly. Butterflies are insects. Insects have three pairs of legs and two pairs of wings. Their body has three sections: head; thorax; and abdomen. Butterflies have large wings that are covered with tiny scales. They have two antennae on the head, each with an enlarged tip. They hold their wings upright when resting. Butterflies are active during the daylight hours.

What Does It Look Like? 
Male tiger swallowtails have yellow wings with black stripes on both their upper and lower sides. The wings also have orange and blue areas on the underside. The female has two color forms. In one of them, she is colored like the male but also has large, shiny, blue areas on the upperside of the hindwings. This form is more common in the northern one-third of the state. The other female form is all black, although the black stripes can be seen on the underside of the wings. The dark female form is more commonly seen in the southern two-thirds of the state. There is a projection from the rear edge of each hindwing. The caterpillar is dark green with two large eyespots behind its head. 

How Big is It?
The average wingspan for a tiger swallowtail in Illinois is three and five-eighths inches to six and one-half inches. Individuals are smaller in spring than at other times of the year.

Where Does It Live?
The tiger swallowtail lives statewide in woods, cities, open fields and gardens.  

How Does It Reproduce?
There are four stages in the life cycle: egg; larva; pupa; and adult. Multiple generations are produced each year. This species overwinters as a chrysalis (pupal stage).

What Does It Eat?
The larva eats the leaves of cherry (Prunus spp.), birch (Betula spp.), tulip poplar (Liriodendron tulipifera) and other trees and shrubs. The adults feed on flower nectar.

Does Anything Eat It?
Many species feed on tiger swallowtail adults and their larvae. Bald-faced hornets (Dolichovespula maculata) and sharp-shinned hawks (Accipiter striatus), great-crested flycatchers (Myiarchus crinitus), barred owls (Strix varia), woodpeckers, American crows (Corvus brachyrhynchos) and other birds are known to eat tiger swallowtails.

What Else Should I Know About It?
The early stages of the caterpillar are colored like bird droppings. The later stages are green with two large eyespots to mimic a snake.

The caterpillar has colorful structures that can be extended from behind the head when it is threatened. They act to startle predators.

Males often gather at damp spots or puddles.

The species is active from March to November.

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