Genetic relationships among certain species of the Aedes (Stegomyia) scutellaris group (Diptera: Culicidae)

Abstract

Genetic affinities between species of the Aedes (Stegomyia) scutellaris group were determined through experimental hybridization. In this investigation Aedes hebrideus and Ae. scutellaris katherinensis were reciprocally crossed with Ae. polynesiensis, Ae. pseudoscutellaris, Ae. kesseli, Ae. malayensis, Ae. alcasidi and Ae. albopictus. Data on insemination and egg hatch rates were recorded in the reciprocal crosses. Of these, Ae. hebrideus and Ae alcasidi, Ae. hebrideus and Ae. s. katherinensis, Ae. malayensis and Ae. hebrideus, and Ae. malayensis and Ae. s. katherinensis, were unidirectionally compatible using female parent of former species of the two. The reciprocal crosses of these laid infertile eggs. Aedes s. katherinensis and Ae. alcasidi were bidirectionally compatible. All other interspecific crosses were incompatible producing infertile eggs. In the compatible crosses, i.e. where the viable hybrids were obtained, F₂ and hybrid fertilities were determined. Species hybrids obtained by crossing Ae. malayensis females and Ae. s. katherinensis males yielded lower fertility in F₂ and differential fertility when backcrossed. Species hybrids obtained by crossing Ae. s. katherinensis females and Ae. alcasidi males resulted in lower fertility in F₂ and also when backcrossed to Ae. s. katherinensis females. All other species hybrids were fertile. Based on the data obtained, Ae. hebrideus, Ae. s. katherinensis, Ae. malayensis and Ae. alcasidi formed a sub-grouping which showed remote genetic affinities individually or as a group with rest of the species investigated.