Eastern Black Swallowtail

Papilio polyxenes

        

 
The Eastern Black Swallowtail is one of the most commonly encountered garden butterflies.  It is at home in open fields, meadows, vacant lots, cultivated farmland, backyards and along roadsides.  The increased human population has brought about an increase in the cultivated and native plants that the larvae of the Eastern Black Swallowtail depend on, thus making this an extremely adaptable suburban butterfly.  Black Swallowtails occur throughout almost all of North America.

The upper surface of the wings is mostly black; on the inner edge of the hindwing is a black spot.  In the center of the black spot is an orange spot.  Males have a yellow band near the edge of the wings; female has row of yellow spots.  The females hindwing have an iridescent blue band.  The wingspan of the Black Swallowtail is 3-1/4 to 4-1/4 inches, although slightly larger individuals have been observed.

 

Description of the different stages of   the life-cycle: 

Egg:   Yellow, spherical eggs.

 

 

Caterpillar:  Very young larvae are patterned like bird droppings.  Older caterpillars are very conspicuous; lime green with each segment crossed by a prominent black band with yellow dots.  Caterpillars eat leaves of plants in the parsely family (Apiacea) including Queen Anne's Lace, fennel, carrot, celery and dill.  Sometimes plants in the citrus family (Rutaceae) are preffered including rue (Ruta graveolens).

 

 

Pupa:  The caterpillar turns into a chrysalis; this is a resting stage.  As the body transforms into a butterfly, it neither eats nor drinks. Chrysalids can over-winter.

 

 

Adult:  Favorite nectar sources include red clover, milkweed, garden phlox and thistles.  Male Black Swallowtails are agile, and strong fliers.  They often are observed dashing along at a rapid clip only a few feet above the ground.  Like other patrolling butterfly species, Black Swallowtails are drawn to land prominences, such as hilltops, where they actively search out receptive females.  Males perch and patrol for receptive females.  Females lay eggs singly on leaves and flowers of the host, which are then eaten by hatching larvae.  

 

Habitat and Range:

A variety of open areas including fields, suburbs, marshes, deserts and roadsides.  from southern Canada along the eastern Rockies into Arizona and Mexico and east to theAtlantic.

Flights:

One-2 flights from April-October in northern regions of range; 3 flights in southern regions.

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