Much like ladybugs and butterflies, caterpillars are considered by many to be approachable insects that can be fun to handle. However, this is not the attitude to take when encountering venomous caterpillars, as there are several caterpillar species in Louisiana that have venomous spines protruding from their bodies. These “spines” are called “urticating hairs,” and simply touching a venomous caterpillar is enough to cause lasting intense pain and potentially dangerous allergic reactions.

Venomous caterpillars are often found within residential yards in Louisiana, and it is not uncommon for people to sustain stings while performing yard work, and in some cases, stings occur after caterpillars fall from trees and land on humans. Tragically, it is also not uncommon for young children to touch venomous caterpillars out of curiosity when the larval insects are spotted within yards. Many venomous caterpillar species are appealing to children due to their seemingly furry appearance, but what appears to be fur is actually venomous urticating hairs. Some of the most commonly encountered venomous caterpillar species in Louisiana include io moth-caterpillars, tussock moth-caterpillars, asp-caterpillars and saddleback caterpillars. Both tussock moth-caterpillars and asp caterpillars are known for causing particularly painful stings, and in some rare cases, anaphylactic shock, which can be fatal.

A one year study of 112 caterpillar stings sustained within Louisiana found that 96 percent of sting victims experienced severe pain, 89 percent experienced erythema, 72 percent experienced edema, and systemic responses occurred in 26 percent of sting victims. Systemic symptoms included vomiting, headaches, chills, fever, and muscle spasms. Experts were able to identify the species of 68 percent of the caterpillars that caused these venomous reactions. Four species accounted for a majority of the stings. These four species were buck moth-caterpillars, io moth-caterpillars, southern flannel moth-caterpillars, and saddleback caterpillars. Only 16 percent of the sting victims had an allergy to insect venom, and a whopping 61 percent experienced lasting pain and other symptoms for at least 24 hours.

Have you ever encountered a venomous caterpillar within your yard?