The Ecology of Baculoviruses
Jenny S. Cory
from: Insect Virology (Edited by: Sassan Asgari and Karyn N. Johnson). Caister Academic Press, U.K. (2010)
Ecological studies involving insect viruses have centred on baculoviruses, partly because they are associated with population declines of some insect species, and also because they are highly pathogenic to insects, making them ideal candidates for pest control. Recent research has focussed on four main areas; (i) the influence of host condition on resistance to viral infection, (ii) the role and maintenance of baculovirus diversity, (iii) the prevalence of covert infections, and (iv) the elucidation of patterns of host resistance in field populations. Tritrophic interactions, either via direct effects of plant secondary chemicals or through nutritionally mediated changes in host immunity, can have a significant impact on baculovirus efficacy. Variation within baculovirus populations appears to be ubiquitous, and mixed genotype infections apparently act to generate higher levels of pathogenicity. Covert infections are increasingly being shown to be common in field populations of Lepidoptera but their importance in generating overt baculovirus infections is still unclear. Field studies on forest insects indicate that host resistance varies with fluctuating host density and condition. Synthesis of the impacts of host condition on susceptibility, the role of genetic variability in infection, and of the relationship between overt and covert infection, will promote understanding of the ecological interactions between baculoviruses and natural host populations.