TRAITS THAT DISTINGUISH OUTBREAKING AND NONOUTBREAKING MACROLEPIDOPTERA FEEDING ON NORTHERN HARDWOOD TREES

Life cycle traits of outbreaking and nonoutbreaking species of Macrolepidoptera feeding on hardwoods are compared. Nonoutbreaking and outbreaking species differ in several ways. The majority of outbreaking species either begin feeding in the spring or are gregarious, summer feeders. Diet breadth and fecundity of outbreaking species are greater, and outbreaking species also appear to be better defended against predators. No differences in size or number of generations per year were found. Spring feeding involves a risk of asynchrony with host leaf emergence. Summer feeding species that outbreak are mostly colonial, and high between-colony variance in survival may cause fluctuations in population sizes.