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Eastern Tent Caterpillar Overview

May 22, 2025

Eastern Tent Caterpillar (Malacosoma americanum)

Overview

  • Eastern tent caterpillars are social insects known for building silk nests in trees.
  • Commonly found in cherry, apple, and various other trees.
  • Recognized more often by their nests than their appearance.

Appearance

  • Inhabit silk tents in tree branches, particularly in the crotches of trees.
  • Dark larvae with white stripes down their backs and brown/yellow broken lines on the sides.
  • Blue oval spots are visible along their sides.
  • Moths are drab with parallel cream lines on tan or reddish-brown wings.

Habitat and Distribution

  • Found throughout the eastern United States, extending to the Rocky Mountains and southern Canada.
  • Prefer sunlit areas and are rarely found in shaded woods.

Life Cycle

  1. Egg
    • Female lays 200-300 eggs in late spring.
  2. Larva
    • Develop in a few weeks but remain dormant until spring when leaves appear.
  3. Pupa
    • Spin silken cocoons; pupal case is brown.
  4. Adult
    • Moths emerge in May and June, living only to reproduce.

Feeding Habits

  • Prefer cherry, apple, plum, peach, and hawthorn trees.
  • Can cause defoliation if populations are high.
  • Adult moths do not feed.

Special Adaptations and Defenses

  • Communal living in silken tents helps maintain warmth in fluctuating spring temperatures.
  • Caterpillars huddle for warmth and add silk to tents regularly.
  • Use silk trails and pheromones for communication and food location.
  • Bristles deter predators; caterpillars thrash to ward off threats.

Importance

  • Often a concern for homeowners due to their presence on ornamental trees.
  • Do not typically harm healthy plants.

Related Species

  • Can be confused with gypsy moths and fall webworms.

Sources

  • Texas A&M University and University of Kentucky Agriculture Department.
  • Books: "The Tent Caterpillars" by T.D. Fitzgerald, "Insects: Their Natural History and Diversity" by Stephen A. Marshall.