Drosophila serrata

Drosophila serrata complex

Drosophila serrata complex—first reference Bock & Wheeler, Univ. Texas Publ. 7213, p. 49 Bock & Wheeler (1972) note that “the most extensively studied complex in the montium subgroup from the point of view of speciation and incipient speciation is that consisting of the three species D. serrata, D. birchii and D. dominicana ”. We can find no earlier mention of the “ serrata complex” in the literature, although Ayala refers to the “ serrata group” in the title of his 1965 papers (1965a, b), nor is there a formal description of the morphological characteristics of such a complex. It should be noted that the term “species complex” is not a formal taxonomic category.

After D. serrata was described by Malloch (1927) from Eidsvold, Queensland (not “Esdivold” as is written on the label of the type specimen, and not “Eidsvolt” sensu Bock & Wheeler 1972), Dobzhansky & Mather (1961) detected a very similar form from Papua New Guinea and northern Australia and designated it as a D. serrata subspecies: D. serrata birchii. Ayala (1965a), tested sexual isolation between these two forms and a third (very closely resembling D. birchii), known only from Madang on the north coast of Papua New Guinea. His findings resulted in the reclassification of D. serrata birchii as D. birchii, and nomination of the Madang fly as D. dominicana (Ayala 1965b). Following on from the work of Ayala (1965a), Baimai (1970a) studied incipient speciation within D. birchii, and confirmed Ayala’s earlier conclusion that the populations of this species from Rabaul (New Britain), from mainland Papua New Guinea, and from northern Australia comprise a series of populations partially reproductively isolated from one another. Baimai (1970b) also found that several of the at least 40 polytene chromosome inversions in D. birchii are unique to specific geographic areas. Investigations of ND5 microsatellite variation in Australian populations of D. birchii have revealed no significant geographic structure and low nucleotide diversity (Kelemen & Moritz 1999).