Anopheles culicifacies Giles: a release-recapture experiment with cohorts of known age with implications for malaria epidemiology and genetical control in Pakistan

Abstract

A mark-release-recapture experiment with the progeny of wild collected Anopheles culicifacies was performed during the monsoon season of 1978 at the village of Khano-Harni, a malarious area situated in Lahore District, Punjab Province, Pakistan. The recapture rates of males and females released at breeding and resting sites were statistically comparable and totalled 8·0% for females and 5·9% for males collected resting in houses and cattle sheds. Mating occurred mostly on the night following the evening of release when the females were about two days old. Insemination rates for females released at resting and breeding sites were statistically comparable. The initial gonotrophic cycle required four days; subsequent cycles occurred at two-day intervals with re-feeding on the same night as oviposition. Constant daily survivorship estimated from the decline in recaptures per day was 0·568 for females and 0·676 for males. Female survivorship estimated by vertical age grading methods ranged from 0·472 to 0·820. Horizontal life tables were calculated from the decline in recaptures and from vertical age-grading techniques and indicated that female or male life expectancy at emergence was less than 2·5 days. Population size was calculated using the Lincoln Index, Jackson's positive and negative methods and Ito's modification of Jackson's positive method and averaged from 1045·5 to 1049·6 females and from 449·1 to 1323·7 males. The relationship of these results to malaria transmission and genetical control is discussed.