Southwestern Distribution and Habitat Ecology of Gryllodes supplicans

Abstract

The “Indian house” or “decorated” cricket, Gryllodes supplicans (Walker), probably existed in Tucson, Ariz. from the late 1940s (verified 1963). Its local populations have expanded dramatically in Thcson and other Arizona cities over the past decade, and the species has extended its range to include other southwestern United States cities. It is found in urban ecosystems in the arid Southwest from sea level to 750 m and is most numerous in high-density residential developments. It is distributed along the Pacific coast of southern California, and north along the Colorado river into Nevada below 36° N latitude. This is the first report of the natural occurrence of G. supplicans in the United States outside of Florida. In Thcson, G. supplicans populations fluctuate with temperature and rainfall. Populations attain highest levels in the hot rainy months ofJuly and August. The origin of the southwestern United States population is not known, but its recent dramatic geographical and ecological expansion suggests that urban demes have coalesced coincident with urbanization and that the Southwest population may have evolved greater tolerance for arid environments.