Surveillance studies of Orthopodomyia signifera with comparisons to Aedes sierrensis

The oviposition behaviors of Orthopodomyia signifera and Aedes sierrensis w ere examined with ovitraps and larval surveys during a five-year field stud y in northern California. Ovipositional periodicity was found to be an impo rtant factor affecting the segregation of the species into tree holes that were temporarily (Ae, sierrensis only) or permanently (both species) filled with water. Orthopodomyia signifera females also used cues associated with the permanence of the habitat when selecting oviposition sites. The distri butions of the eggs of each species along horizontal and vertical transects did not indicate that interspecific competition affected oviposition site selection. The data indicate that temporal partitioning of larval developme nt may reduce interspecific competition. Ovitraps were determined to be mor e sensitive tools for surveillance of Or. signifera than larval surveys, CO 2-baited Fay traps and CDC light traps.