Few insects are more intriguing to children than the wriggling worm-like caterpillars that can be found in your own backyard throughout the spring and summer months. Since many kids simply can't resist snatching up a caterpillar once it is discovered crawling across a driveway or wandering along a low-hanging tree branch, many parents have stopped to wonder, "Are caterpillars poisonous?"
What is a caterpillar?
Caterpillars come in a wide array of shapes, sizes and species, however, all of these infamous insects have one thing in common: they are larval stage of butterflies and moths. When a female moth or butterfly reproduces and lays its eggs, the eggs hatch and caterpillars emerge. These tiny insects consist of a segmented body, which contains a head, thorax and abdomen. Caterpillars remain in this stage of the lifecycle for two weeks to one month, depending on their species, and consume a considerable amount of vegetation during this time period. Their powerful mandibles easily chop through the leaves of plants, allowing caterpillars to devour enough plant material to accommodate their rapid growth and to store plenty as a source of energy to sustain their lives once they continue into the pupal stage of metamorphosis.
Are caterpillars poisonous?
Caterpillars may appear harmless, and it's hard to believe these tiny worm-like insects that transform into beautiful butterflies could pose a threat to human beings, however, some species of caterpillar are indeed poisonous to people and pets. Some caterpillars-such as the Pipevine Swallowtail and the Monarch-develop their toxicity from the plants they consume and can cause damage to predators who attempt to eat them. These species typically cause symptoms ranging from nausea to vomiting, although the predators rarely die from such exposure to the poison contained in the caterpillar.
The vast majority of poisonous caterpillars only pose a threat to predators like birds whose main mission is to capture and consume the caterpillar, however, some species can also harm human beings who come into contact with them. Perhaps the most common poisonous caterpillar that makes its home in backyards and wooded areas across the United States is the wooly bear caterpillar. Characterized by a long, thick, fur-like covering, wooly bear caterpillars are most often black in color with a copper-colored band around the middle portion of their bodies, although they also exist in hues that range from yellow to a dull orange.
Although the wooly bear caterpillar-which is the larva of an Isabella tiger moth-does not bite or sting as some poisonous insects do when threatened or disturbed, this particular species uses its bristly fur to inject the poisonous remnants of plant material they have consumed. Picking up or handling a wooly bear caterpillar can cause severe irritation of the skin and dermatitis to develop, particularly in people with sensitive skin.
The wooly bear caterpillar might be the most common poisonous caterpillar that makes its habitat near human beings in the United States, however, a wide array of additional species found all around the world pose a much more serious threat to people. The Bag Shelter Caterpillar is a poisonous species that no human being or animal should ever touch or disturb for any reason. These highly toxic caterpillars are named for the brown bag made of silk that they reside in during the larval stage and are considered a major threat to public health in their native lands of South America. When disturbed, a Bag Shelter Caterpillar will use its venom-filled bristles to defend itself. The poison injected by this species is extremely anti-coagulant, making it possible for those who encounter this type of caterpillar to bleed to death from even a tiny open wound.