Nature Notebook – Stinging Caterpillars
Full of protein without pesky bones, caterpillars are the prime ingredient for many animals’ summer fare. Considering the numbers eaten (300 per day for a goldfinch family or 25,000 in one day for a black bear), it’s a wonder any survive to become butterflies or moths.
Defense adaptations for caterpillars are as varied as the caterpillars themselves: nasty-tasting bodies, protective coloration, defensive behaviors, whistling, etc.
Probably the most effective strategy is to sting the predators. Specialized hollow hairs or spines on the caterpillar body contain venom. One poke of these hairs can cause mild discomfort, excruciating pain or even death for any animal or human who touches these caterpillars.
However, black cuckoos especially love eating hairy tent caterpillars and do so without any problems. Black bears also love those prickly guys. The ovipositors of parasitoid wasps are long enough to avoid the spines.