Phosphoglucomutase (PGM) allozymes in two forms of the mariae complex of the genus Aedes.

Abstract

The mariae complex of the genus Aedes includes at least three apparently allopatric forms which are slightly differentiated morphologically and show varying degrees of hybrid sterility (Coluzzi and Sabatini, 1968; Coluzzi et al., 1970). A complete sterility barrier was shown to exist between phoeniciae and the other two members of the complex, and, according to this evidence, it has been proposed thatphoeniciae is a valid species. Hybrid sterility also occurs between mariae and zammitii. However, only the Fj hybrid males show sterility in this cross, while the F~ hybrid females are fertile. Considering the evidence for introgressive hybridization in the laboratory and the lack of data on reproductive isolation in nature, mariae and zammitii were tentatively treated as subspecies. The present report deals with rnariae and zarnrnitii. Single populations belonging to these forms were examined by comparing the phosphoglucomutase (PGM) patterns obtained with electrophoresis. The two populations were found to be monomorphic for distinct PGM electrophoretic patterns, and the genetic basis of such differences was studied. The samples of mariae and zammitii examined were from Sperlonga (Tyrrhenian coast) and from Peschici (Adriatic coast), respectively. Fourth instar larvae and pupae were collected from no less than 12 rock pools in each locality during May-August 1970. Homogenates of single adult mosquitoes from these collections were examined for PGM content utilizing, with minor modifications, the electrophoretic method described by Spencer et al. (1964). Strains from Sperlonga and Peschici were also used for the crosses. Many samples of the natural populations of zarnmitii from Peschici and of rnariae from Sperlonga were tested at various times. More than 500 individuals from