Caterpillars in Your Yard and Garden
Zebra swallowtail caterpillars (Graphium marcellus) are present from May to November. They produce two to three generations per year.
Full-grown zebra swallowtail caterpillars appear hump-backed with a swelling between the thorax and abdomen. Most body segments are ringed with transverse lines of yellow-white and green. The anterior part of the first abdominal segment has a thick black ring that extends partway down the sides. The preferred host plant is pawpaw.
About the family
Swallowtail caterpillars of the Papilionidae family are usually smooth-bodied and vary in color from green or yellow-orange with black markings to a color pattern that gives them the appearance of a bird dropping or the head of a vertebrate with conspicuous “eyes.” All swallowtail caterpillar species possess a scent gland called an osmeterium that is located just behind the head. When disturbed, this fleshy-looking, forked, orange-red gland is everted from its pouch and releases a disagreeable odor. Because the caterpillars are relatively large and very colorful, they too (with royal and silkworm caterpillars) are quite noticeable. Very few species would be considered important pests. Many adults from this family are colorful and beautiful medium-size to large butterflies. Their name is derived from the presence of tail-like projections on the hind wings.