The term “pussy bug” is a common misnomer for certain caterpillars, particularly those with a dense, fur-like appearance, which can deliver a surprisingly painful sting. This article clarifies their identity and provides practical information on handling encounters.
Unmasking “Pussy Bugs”
The insect commonly called a “pussy bug” is the puss caterpillar (Megalopyge opercularis). It is also known as the asp caterpillar, tree asp, fire caterpillar, woolly slug, and southern flannel moth larva. Its distinctive appearance, resembling a small tuft of cotton or a miniature Persian cat, comes from its long, hair-like setae. Puss caterpillars are typically about one inch long, teardrop-shaped, and vary in color from grayish-white to golden-brown or dark charcoal gray, sometimes with orange streaks. This caterpillar is the larval stage of the southern flannel moth, a furry moth with a wingspan of 1 to 1.5 inches, completing a life cycle from egg to larva, pupa, and adult.
The Danger They Pose
Puss caterpillars are considered one of North America’s most venomous caterpillars. Hidden beneath their dense, fur-like exterior are hollow, venomous spines. When skin brushes against these spines, they break, releasing a potent fluid that causes a painful reaction. The sting’s severity varies based on individual sensitivity and skin thickness. Contact typically results in immediate, intense throbbing pain, often described as similar to a broken bone or burning. This localized pain can be accompanied by a red, itching rash, swelling, and a grid-like pattern. In some cases, more severe systemic symptoms like nausea, headache, fever, muscle cramps, chest pain, abdominal distress, and numbness can develop. While rare, these reactions highlight the caterpillar’s potent defense.
What to Do After a Sting
Immediate action after a puss caterpillar sting can alleviate discomfort. First, remove embedded spines by gently pressing adhesive tape onto the skin and pulling it off, repeating several times. After spine removal, wash the sting site thoroughly with soap and water. Apply a cold compress or ice pack for 10 to 15 minutes to reduce pain and swelling.
Over-the-counter pain relievers like acetaminophen or ibuprofen can manage pain, and antihistamines may relieve itching. Calamine lotion or a baking soda paste can also soothe the skin.
Seek medical attention if pain is severe, symptoms worsen, or systemic reactions like widespread rash, difficulty breathing, or severe nausea occur. Children, individuals with known allergies, or those with pre-existing health conditions should also consult a healthcare professional. Ensure tetanus immunization is up to date.
Prevention and Habitat
Puss caterpillars are found throughout the southern United States, from Maryland to Florida and west into Texas and Missouri. They inhabit wooded areas, gardens, and residential neighborhoods. These caterpillars feed on deciduous trees and shrubs like oak, elm, maple, sycamore, hackberry, and ornamental plants such as roses and ivy. Peak abundance occurs in July and October, corresponding to their two generations per year. To avoid accidental stings, educate yourself and others, especially children, about not touching unknown caterpillars. When gardening or working outdoors where these caterpillars are present, wear protective clothing, including long sleeves, long pants, and gloves. Always inspect plants and tree branches before handling them, as these caterpillars can be well-camouflaged. If a puss caterpillar is spotted, observe it from a distance and avoid direct contact.