ROLE of RESERVOIR HABITATS and POPULATIONS in the URBAN ENVIRONMENT

Abstract:
Pest status of household and structural pests is based primarily on their persistence in the urban environment. Persistence of pest populations is determined by availability of reservoir habitats that harbor large and stable populations, which supply individuals to maintain small, local infestations. Success of pest species in the urban environment is dependent on a network of infestations and reservoir populations. Decline of pest species is linked to reduction or elimination of reservoir populations. The role of reservoir habitats and populations in the persistence of German and American cockroaches, old house borer, and American and European dust mites is discussed. Blattella germanica survives as a pest only indoors in local infestations and a limited number of urban reservoir populations. The importance of these populations is evident in the decline in abundance and reduced pest status of this cockroach. Periplaneta americana lives in local infestations outdoors and indoors, and is supported by reservoir populations in urban sewers. There is limited potential for reducing its reservoir habitats, and it is likely to maintain its pest status. A cerambycid Hylotrupes bajulusoccurs only in local infestations of structural softwoods in urban and rural buildings, and in reservoir populations in lumber storage sites. Effective control of structural infestations and improvements in lumber storage have removed the key reservoirs needed for persistence of this pest. Dermatophagoides spp. dust mites depend on small, local populations to persist in the living space. Long- term pest status of these mites is expected because of the relative ineffectiveness of cleaning to remove enough of a pest population to achieve reduction, and the ease in which mites are carried to new sites or existing infestations.