Why do certain ants thrive in the urban environment?
  Key Words  
  Urban ants, tramp species, invasive species, behavior, ecology
  J. Silverman
  Of the nearly 10,000 known ant species, less than 100 are considered pests and fewer than 30 have adapted to urban disturbance. Some species, such as the Pharaoh's ant have a truly cosmopolitan distribution, nesting in and out of doors in tropical climates and only indoors in temperate climates. Most urban ants require moist nesting substrates, found primarily outdoors, thereby considerably narrowing their range to that within suitable climates. The success of the most serious urban pest ants is most likely due to a combination of limited intraspecific aggression, a possible consequence of reduced genetic diversity following escape from the native range, and release from ecological constraints. I will review the behavioral and ecological determinants that are thought to be responsible for the broad distribution and success of urban pest ants.