There are an estimated 1,000 species of Hawaiian Drosophilidae. Within the Hawaiian
Drosophila there are several major groups, including the
modified-mouthpart,
modified-tarsus, and
antopocerus species groups, and the picture-wing clade. or as the result of one colonization by the common ancestor of
Scaptomyza and Hawaiian
Drosophila, followed by several migrations back to continents.
Scaptomyza is one of several genera that are currently nested within the genus
Drosophila, rendering it
paraphyletic. This clade includes the
grimshawi, planitibia, and
adiastola species groups, among others. Research on the taxonomy and biology of picture-wing flies in the 1970's led to the description of 105 species, with several more described in the decades since. More recent studies on variation in wing patterns has led to the generation of a database devoted solely to wing diversity in the Hawaiian
Drosophila lineage. These flies have also been extensively studied for their courtship behavior, potential for hybridization between species, and larval ecology. Many species of picture-wing flies breed in rotting bark and stems.
Antopocerus was previously considered as a distinct genus, before being sunk into the genus
Drosophila based on their phylogenetic position within other Hawaiian lineages. Species of
antopocerus flies have been described from the islands of
Maui,
Molokai,
Lanai,
Hawaii, and one species from
Oahu. The
modified-tarsus species group is so named because of the variation in the shape and structure of front
tarsi of males. This large group of flies has received relatively less study, in part due to their rarity and because many species are not attracted to typical
Drosophila baits. These flies show a remarkable diversity in breeding ecology, with the majority of species using more than one host family for larval feeding. Rearing records indicate that members of this group breed exclusively on fungus. These species are characterized by their simple courtship displays, relative to some picture-wing species, and the short filaments on their eggs. Some species also have a black rim on the
labellum.
Rustica species group This enigmatic species group includes three species, described from
Oahu,
Molokai, and
Hawaii, that been historically difficult to place within Hawaiian
Drosophila because they display traits similar to multiple other groups. These traits include a sclerotized rim on the labellum, reminiscent of several
haleakalae species, and tarsi with cilia, reminiscent of
ciliated-tarsus species in the AMC clade. == Research ==