The saddleback caterpillar, known scientifically as Acharia stimulea, is a distinctive insect recognized for its striking and unusual appearance. This creature, often encountered in gardens and natural areas, goes through a complete metamorphosis, transforming dramatically as it develops. Its remarkable larval stage is a stark contrast to its final adult form, which serves a different purpose in its life cycle.
The Saddleback Moth: The Final Form
The saddleback caterpillar transforms into a moth (Acharia stimulea). Unlike its vibrant larval stage, the adult moth has a camouflaged, subdued appearance. Its wings are typically glossy dark brown, often with black shading, and the hindwings are a paler cream or brown. Both the wings and body have a velvety, fur-like texture.
The adult moth is moderate in size, with a wingspan of 26 to 43 millimeters (1 to 1.7 inches); females are generally larger. Distinctive white dots mark its forewings, usually one near the base and one to three near the wing’s apex.
These moths are primarily nocturnal, flying during warmer months, from July and August in northern regions to year-round in the extreme South. The adult saddleback moth is harmless and does not sting.
The Complete Life Cycle
The saddleback moth undergoes a full metamorphosis, transitioning through four distinct stages: egg, larva (caterpillar), pupa, and adult. The female moth lays between 30 to 50 tiny, flat eggs, typically in clusters on the upper surface of plant leaves. These eggs usually hatch after about 10 days.
Once hatched, the larva, or saddleback caterpillar, begins its feeding and growth phase, molting several times as it progresses through various instars. This caterpillar stage can last for approximately four to five months before the larva is ready to pupate.
The caterpillar then forms a tough, silken cocoon, often overwintering within it, particularly in temperate climates. The cocoon itself may also contain irritating hairs. Finally, the adult moth emerges from the cocoon, typically in the spring or summer, ready to reproduce, living for about 10 days.
Recognizing the Saddleback Caterpillar and Moth
The saddleback caterpillar has highly distinctive features. It typically has a vibrant green body with prominent brown areas at both its front and rear ends. Its most recognizable marking is a central, brown, saddle-shaped spot enclosed by a white ring, which gives the caterpillar its common name. It also possesses fleshy, horn-like projections at both ends of its body. When mature, these caterpillars measure 0.75 to 1 inch in length and move in a slug-like manner.
Safety and Handling Precautions
Direct contact with the saddleback caterpillar’s spines can result in a painful sting, a defense mechanism against potential threats. The caterpillar’s body is covered in numerous stinging spines, particularly on four prominent knobs at the front and rear, and smaller ones along its sides.
The sting typically causes immediate burning sensations, swelling, redness, itching, and the development of a rash or welts. In some instances, contact can lead to more widespread symptoms such as nausea, migraines, or gastrointestinal upset.
The hollow spines contain a toxin, breaking off in the skin upon contact and releasing the irritant. These spines can also become airborne.
If stung, it is important to remove any embedded spines immediately by gently pressing adhesive tape onto the affected area and then pulling it away. Following this, wash the area thoroughly with soap and water. Applying an ice pack can help alleviate pain and swelling, and a paste made from baking soda and water may also provide relief.
It is always advisable to observe these caterpillars from a distance and avoid handling them directly. Wearing gloves when gardening can help prevent accidental contact. If symptoms are severe or persist, seek medical attention.