White-marked tussock, Orgyia leucostigma, caterpillars are a crowd favorite, and even years into rearing them, breeding them, and exploring their bizarre natural histories, we are still witnessing and capturing new behaviors to share with you here.
After each shed, the caterpillars find themselves immediately vulnerable. Their arsenal of different defensive setae, or hairs, are wet and matted and relatively useless against any attackers that happen by. So what do they do? They twist and dance to fluff up their hairs and spines!
Most hairy caterpillars writhe and twist to engage their defenses after a shed, but the Orgyia tussocks go further. They need to rub their hairs across a set of red irritant glands on their abdomen, coating them with a special secretion. Now the spines are erect and armed to make the unsuspecting caterpillar enthusiast quite itchy!
The dance, the setae, the irritant, are just part of an ongoing story that culminates with the tussock caterpillars giving themselves a haircut, weaving the hairs into their cocoons, and providing a defense to their future selves as pupa, as moths, and if female, their future eggs and hatchling offspring.
Very cool caterpillars,