Morphological variations in male genitalia of seven mosquito genera (Diptera: Culicidae) in Kandy, Sri Lanka

Abstract

Disease-causing vector mosquitoes are prevailing throughout Sri Lanka, hence proper identification of these mosquitoes is crucial in implementing effective mosquito control approaches. The use of taxonomic keys based on external morphological characters of adults and larvae, is the common identification method. Due to the high diversity, abundance and presence of species complexes, proper identification using external morphology is challenging. The molecular approach is well-known but a costly method of mosquito identification in the country. This study was proposed to identify the variations in the male genital anatomy of mosquitoes from the Kandy District, Sri Lanka, to be used in mosquito identification. Monthly samplings were done in Peradeniya, Hantana, and Halgolla areas in Kandy, Sri Lanka. Male mosquitoes were identified using standard taxonomic keys. Male genitalia of these mosquito species were slide mounted. Photographs of the genital structures were taken. Male mosquitoes representing six genera (Aedes, Anopheles, Armigeres, Coquilletidia, Culex and Orthopodomyial) and 15 species were identified based on their external morphological features. Generic and species-specific features of the male genitalia of the studied mosquitoes were primarily seen in the gonocoxite, gonostylus, claspette, and phallosome. Speciesspecific features identified in the genitalia of mosquitoes are more reliable in accurately identifying male mosquitoes.

Entomological Surveillance and Alternate Methods for Species Identification of Aedes in a Dengue-endemic District of Punjab, India

“…though there are some other distinguishable characteristics also which can be used for the identification as they are not lost in transportation and storage. 5,11 In India, very few studies have been conducted on the comprehensive analysis of male and female genitalia of Aedes species. In this study, an effort has been made to understand the anatomical differences in male and female genitalia of Aedes species detected in the study areas.…”

“…4 The most common method for the identification of species of mosquitoes is following the standard morphological keys developed on the basis of external morphological characteristics and distinguishing features of different species but it can become difficult in case of damaged specimens and following the developed molecular technique is not possible for vector control programmes as it is not cost-effective and requires well-equipped laboratories. 5 Thus, the most reliable and economically feasible method for morphological identification is to study and identify the species-specific structural features of the genitalia of mosquitoes. The genital features of male and female mosquitoes are a modified structure beyond the eighth abdominal segment which differs considerably among the different genera.…”