The luna moth, a striking insect native to North America, is widely recognized for its vibrant lime-green wings and graceful appearance. This iconic moth, Actias luna, often sparks curiosity, especially regarding its larval stage.
Are Luna Moth Caterpillars Harmful?
Luna moth caterpillars are not poisonous, venomous, or capable of stinging or biting. They are considered harmless to humans. Their primary defense mechanisms are behavioral rather than chemical. When disturbed or threatened, a luna moth caterpillar may rear up its front body in a sphinx-like stance. This posture can be accompanied by a clicking sound made with their mandibles, serving as a warning.
Following this warning, the caterpillar might regurgitate a foul-tasting, green liquid from its digestive tract. This fluid is a deterrent to predators but is not harmful to humans upon contact. The spines or bristly hairs on their bodies do not contain any chemical irritants. While generally safe to touch, it is always best to avoid unnecessary handling of any wild animal.
Identifying a Luna Moth Caterpillar
Luna moth caterpillars possess distinct physical characteristics. They are typically a vibrant lime green color, with a segmented body that can appear somewhat textured. Along their sides, they feature rows of small, often reddish-orange or yellow tubercles (bumps), some of which may have sparse, bristly hairs. A yellowish lateral stripe may also be visible.
These caterpillars can grow quite large, reaching lengths of approximately 2.5 to 4 inches before they are ready to pupate. Their diet consists of leaves from various broadleaf trees. Common host trees include sweetgum, walnut, hickory, pecan, persimmon, sumac, and birch.
Encountering a Luna Moth Caterpillar
If you encounter a luna moth caterpillar, the best approach is to observe it from a respectful distance. These caterpillars are harmless. They are not considered agricultural pests because their populations rarely grow large enough to cause significant defoliation of trees.
Handling the caterpillar should be avoided unless absolutely necessary, such as if it is in a dangerous location like a road or sidewalk. In such cases, gently moving it to a nearby host plant or a safer spot using a stick or a large leaf is advisable. Allowing them to complete their life cycle undisturbed is beneficial for their survival. The caterpillars will eventually descend from their host plants to spin a cocoon in leaf litter on the ground, where they will undergo metamorphosis.