Catalpa worms are a common sight in some parts of the United States. These creatures are the larval stage of the catalpa sphinx moth with a specific relationship to the catalpa tree. Sporting prominent black and yellow markings and a unique horn-like structure at their rear, their presence is almost exclusively linked to catalpa trees, which serve as their sole food source.
Understanding Catalpa Worms
Catalpa worms are caterpillars of the catalpa sphinx moth. The life cycle of this insect begins when the adult moth lays clusters of eggs on the underside of catalpa tree leaves. Once hatched, the caterpillars feed voraciously on the leaves, growing through several stages. After reaching maturity, they burrow into the soil to pupate, eventually emerging as adult moths.
These caterpillars feed exclusively on the leaves of catalpa trees. While they can sometimes defoliate trees during outbreaks, healthy catalpa trees recover. Catalpa worms also play a role in the ecosystem, serving as a food source for various natural predators like birds and parasitic wasps.
Do Catalpa Worms Bite?
Catalpa worms do not bite humans. Their mouthparts are designed specifically for chewing plant leaves, not for piercing skin.
Concerns about stinging, venom, or being poisonous are unfounded. They do not possess stingers, venom, or toxins harmful to humans. The prominent “horn” on their rear is a harmless spine, a characteristic feature of sphinx moths, and not a defensive weapon. While handling them, they may excrete a brownish or yellowish fluid, which can stain hands but is completely harmless.
Safe Handling and Common Uses
Given their harmless nature, catalpa worms are safe to handle directly. Many people interact with them, particularly those who use them for fishing. Their widespread use as a highly effective fishing bait is a primary reason for human interaction.
These caterpillars are a popular choice for catching various freshwater fish, including catfish and bream. Anglers often collect them from catalpa trees, sometimes even planting the trees specifically to cultivate the worms for bait. Catalpa worms can be used fresh or preserved for later use by briefly boiling them and then freezing them. Always wash your hands after handling any wildlife, including catalpa worms.