Adult and larval Black Swallowtails may be so abundant because they have great defensive strategies: excellent mimicry and an acrid discharge.
The Black Swallowtail looks almost identical to the pungent-tasting Pipevine Swallowtail. This mimicry is a good defense against predators. The caterpillar of the Black Swallowtail also has a defensive organ called an osmeterium. This "Y" shaped, fleshy organ is normally hidden, but will protrude if the caterpillar is threatened. It can then emit terpenes, an organic chemical that smells quite foul and discourages would-be predators from eating the caterpillar.
The body of the Black Swallowtail is black with rows of small white dots running down the length of it. The dorsal (back) view displays black forewings edged in two rows of white dots. Two larger spots are close to the edge. The smaller, black hindwings also have two rows of white dots, but an iridescent blue is sandwiched between them. Each hindwing sports a bright orange and black eyespot at the bottom near the body. The edges of the hindwings are scalloped with white inside the curves. A long extension forms a 'tail' on each wing. Most of the desert populations are more yellow in color, while other populations have less color.
Black Swallowtails can be found in gardens, meadows, forests and other habitats. Adults drink flower nectar and are attracted to fennel plants and flowering herbs like dill. Females lay eggs in spring and caterpillars emerge. Caterpillars eat the leaves of pipevines, Dutchman's pipe, and snakeroot as well as dill, carrots and parsley plants. They form a chrysalis on a stem or branch and tie it to that stem with a single strand of silk. It overwinters in the chrysalis, which turns from green to brown as it ages. Adult butterflies emerge in the spring.
Scientific Name: Papilio polyxenes
Other Name(s): Parsley Swallowtail
Butterfly or Moth
Size (Adult; Length): 67mm to 89mm (2.61in to 3.47in)
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Butterfly and Moth Anatomy
Antennae: Butterflies and Moths have a pair of antennae on the head used as sensors.
Head: The head is home to the insect's eyes, antennae, and proboscis.
Thorax: Home to the three pairs of legs as well as vital internal organs.
Abdomen: Contains vital internal organs such as the heart(s) and reproduction facilities.
Forewing: The upper, forward wing pair used for flying.
Hindwing: The lower, rearward wing pair used for flying.
NOTE: Butterflies and Moths are part of the Lepidopteran order as they share many similarities.