Natural mortality in two filarial vectors.

Little has been written about the survival of filarial mosquitos in nature, although methods are available for determining natural mortality in the field. Every filarial infection in a mosquito provides some information about the number of days it has survived after infection. This can be used to determine the probability of survival of an infected mosquito population in the field. The parous rate of the vector provides another method for estimating natural mortality. Several estimates of natural mortality in two mosquitos, Culex fatigans and Anopheles peditaeniatus, in South India have shown a daily mortality of from 14% to 24% during a season favourable for survival. Information on natural mortality can be obtained during routine dissections of mosquitos for filarial larvae, but a more positive approach to the problem of the identification of filarial infections in mosquitos is needed.