Tent caterpillars are conspicuous because they live together in groups and create “nests of silk webbing in the crotches of trees. During the day, tent caterpillars lounge in the protective confines of the nest. At night, when predators and parasitoids are less active, the caterpillars wander out of the nest to feed on tree leaves.
Caterpillars will leave a trail pheromone behind them as they head for their feeding site. The trail points the way back to the nest and helps recruit other caterpillars. The trail pheromone system is critical to the cohesiveness of the colony.
TD Fitzgerald, in the Journal of Applied Entomology, describes the use of trail pheromone mimics to disrupt tent caterpillar communication. Treating trees with trail pheromone mimics caused 80 percent of the colonies to be completely destroyed, or collapse to single individuals or shelterless fragments.
Many of the caterpillars in treated trees died by falling from the trees. Caterpillars are better able to stay in a tree if there is an extensive network of silk threads attached to the slick tree bark. A single caterpillar may lay only a single strand of silk. Caterpillars in aggregate, directed by trail pheromone will lay multiple silk strands that reduce the probability of fall. Apparently, the trail pheromone is important in directing the structure of the silk trails. The use of a trail pheromone mimic may be a method of controlling tent caterpillars without major effects on other non-target species.