Seasonal population structure of house dust mites, Dermatophagoides SPP. (acari: Pyroglyphidae).

House dust mite density in 5 homes with high mite numbers exhibited a seasonal fluctuation, with peak density occurring during the humid summer months and lowest density during the drier late winter heating season. We hypothesize that house dust mite populations survive dry winter months in homes as desiccation-resistant pharate tritonymphs. This life stage provides the major source of breeding mites for population growth in the spring.