Larval ontogeny and survivorship of eastern tent caterpillar colonies

Abstract

This study documents spatial and temporal variation in mortality in a population of 100 naturally-occurring colonies of eastern tent caterpillars {Malacosoma americanum). Predation took the heaviest toll on colonies, while very few colonies were significantly affected by disease. Predation by invertebrates was widespread, but far less catastrophic than vertebrate (avian) predation. Predation and disease incidence varied considerably among study sites and among larval instars. Early-instar colonies suffered the greatest rates of mortality, with 30% of the colonies destroyed by the instar. Spatial and some temporal variation in mortality and morbidity was stochastic. Temporal variation also arises from individual phenology, as a consequence of larval development and its effects on defense-and foraging-related character suites. The social behaviors of eastern tent caterpillars are discussed in terms of a character suite collectively enhancing larval defense and nutrition, resulting in rapid growth to decreasingly-vulnerable age classes.