METAPOPULATION CONCEPT and the PERSISTENCE of URBAN PESTS in BUILDINGS

Abstract:
The dynamics of colonisation, persistence, and extinction of Blattella germanicaand Plodia interpunctella populations was studied in a hospital kitchen and a food plant. Metapopulations of both pests persisted during the period of the study, despite the presence of regular monitoring and pest control. There was at least one extinction in each local population. Local pest populations did not intercorrelate in both aseasonal B. germanica, with 80% of the cases, or semi-seasonal P. interpunctella, with 83% of the cases. Density-dependent allocation of pesticide treatment created partial refuges for pests. Uneven distribution of pesticides and pests, and asynchrony of local populations apparently facilitated the survival of pest metapopulations. Results are consistent with the implication of metapopulation theory that contradicts the traditional urban IPM concept that pest eradication requires pesticide treatment to currently infested sites but also all suitable refuges that can be recolonized. As an alternative to the physiological hypothesis a metapopulation explanation of the historical success of blatticide baits is presented.