Black swallowtail caterpillar

Open fields, meadows, gardens, roadsides, and other sunny areas with plants in the carrot family (Apiaceae).

Feeds on foliage of Apiaceae, including fennel, dill, parsley, carrot, and native wildflowers such as the plant shown. It may consume flowers and developing seeds as well as leaves.

The caterpillar passes through several molts and often rests exposed on host plants; when disturbed, it may evert an orange, foul-smelling forked gland called an osmeterium. It eventually pupates in a camouflaged chrysalis and emerges as a swallowtail butterfly.

Harmless to people and pets, though it can be a minor garden herbivore. It supports food webs as prey and develops into a pollinating adult butterfly.