Short-Term Population Dynamics of Adult Aedes dorsalis (Diptera: Culicidae) in a Northern California Tidal Marsh

Abstract

Short-term changes in the age structure and abundance of the host-seeking population of Aedes dorsalis (Meigen) females were studied in a Northern California tidal marsh by daily sampling from 25 July through 17 August 1990. The calculated numbers of nulliparous and parous females per day were used to estimate parity rates and duration of the gonotrophic cycle. The numbers of females collected per day ranged from 261 to 74,443, and daily parity rates ranged from 0 to 91%. The overall parity rate was 14%. Two peaks in nulliparous female abundance on days 7 and 12 were followed 5 d later by increases in the number of parous females, indicating that two cohorts had emerged with gonotrophic cycle lengths of approximately 5 d. This is consistent with the 5-d gonotrophic cycle length estimated using time series analysis of the same data sets. Peak host-seeking activity of nulliparous females in the two cohorts occurred 16 d after two marsh systems were flooded by monthly high tides. Survivorship was estimated to be 14% per gonotrophic cycle and 67% per day, although emigration may have caused the substantial underestimation of actual survivorship.