Prevalence and Persistence of Nuclear Polyhedrosis Virus in Fluctuating Populations of Forest Tent Caterpillars (Lepidoptera: Lasiocampidae) in the Area of Prince George, British Columbia

Abstract

Infection by nuclear polyhedrosis virus commonly occurs in outbreak populations of forest Lepidoptera. However, nothing is known about viral infection in populations of forest caterpillars that declined to low density. We used DNA dot-blot hybridization to identify viral infection in caterpillars collected from 6 field populations of forest tent caterpillars in the vicinity of Prince George, BC. Over the 5 yr of observations, populations at 4 sites declined from high to low densities. Viral infection was generally highest among caterpillars from dense and declining populations but persisted at low levels in sparse populations. Populations at 2 sites which erupted in the last 2 yr of the study had levels of infection comparable to populations which were at high density at the beginning of the study.