Black Swallowtail (Papilio polyxenes)
|
|
One of the easiest swallowtails to observe is the Black Swallowtail. It can be seen visiting flowers in the Garden, but is also almost guaranteed to come to any yard in which fennel, dill, parsley, or other plants of the Apiaceae family are growing.
The insect shown in the first two photos is a female. The males have broad stripes of yellow spots that the females lack.
|
Because their food plants are so specific and easy to grow, observing the caterpillars is a simple matter. Even the tiny eggs are visible on the fine foliage of fennel. When the caterpillars first hatch, they have spines and coloring similar to many other swallowtails that resemble bird droppings. These do not mimic the bird droppings, though, and simply have a white "saddle" in their middle. As they grow, the white spot disappears and stripes resembling those of a monarch caterpillar develop.
The photo below at left shows a young larva that still has some spines and the white spot in the middle of its back. The middle photo is a normal colored fully grown caterpillar and the one at the right shows a light colored one. As with many smooth striped caterpillars, the markings on this species are highly variable.
|
|
|
Like all swallowtail caterpillars, the larvae can extrude a bright orange forked, fleshy organ called an osmeterium. This is kept within the body most of the time and is sort of "inflated" when needed. It is connected to a scent gland that produces a repellent odor to help ward off predators.
|
If the caterpillar survives predation, it eventually forms a chrysalis, usually right on the same plants where it fed as a larva. The green color blends in well with living plants, but if the stems die then only the angular shape hides the pupa.
|
class: Insecta / order: Lepidoptera / family: Papilionidae / genus: Papilio / species: polyxenes
| site by larvalbug |
