A method for distinguishing the important malaria vectors Anopheles dirus and An. cracens (Diptera: Culicidae) based on antennal sensilla of adult females

摘要

Some species of the Anopheles dirus species complex are considered to be highlycompetent malaria vectors in Southeast Asia. Anopheles dirus is the primary vector ofPlasmodium falciparum and P. vivax while An. cracens is the main vector of P. knowlesi.However, these two species are difficult to distinguish and identify based on morphologicalcharacters. Hence, the aim of this study was to investigate the potential use of antennalsensilla to distinguish them. Large sensilla coeloconica borne on the antennae of adult femaleswere counted under a compound light microscope and the different types of antennal sensillawere examined in a scanning electron microscope. The antennae of both species bear fivetypes of sensilla: ampullacea, basiconica, chaetica, coeloconica and trichodea. Observationsrevealed that the mean numbers of large sensilla coeloconica on antennal flagellomeres 2, 3,7, 10 and 12 on both antennae of both species were significantly different. This study is thefirst to describe the types of antennal sensilla and to discover the usefulness of the largecoeloconic sensilla for distinguishing the two species. The discovery provides a simple,reliable and inexpensive method for distinguishing them.