In order to detect seasonal trends in the age structure of adult mosquitoes
from Buenos Aires province, Argentina, female populations were sampled with
CDC traps during 1989-1991 in Punta Lara and La Plata. The mosquitoes were
dissected and age-grouped according to ovarian tracheation and ovariolar
stages. All Runchomyia paranensis females were parous, suggesting that this
species could be autogenous. Aedes albifasciatus showed parous peaks
following population peaks, with shorter delays in spring-summmer and
longer in fall-winter. Ae. crinifer and Culex dolosus showed wide
fluctuations in age structure due to adult emergences during all months.
Psorophora ferox showed high population replacement rates. Mansonia
indubitans and Ma. titillans have few generations per year during their
activity period. This is the first report on age-grading of adults of field
mosquito populations from Argentina.