Drosophila ananassae, subgroup

McEvey, Shane & Schiffer, Michele, 2015, New Species in the Drosophila ananassae Subgroup from Northern Australia, New Guinea and the South Pacific (Diptera: Drosophilidae), with Historical Overview, Records of the Australian Museum 67 (5), pp. 129-161 : 154

Key to ananassae subgroup species of Australia and New Guinea

The Drosophila ananassae subgroup flies, in Australia and New Guinea, are small (2–3 mm) pale yellowish-tan flies that frequently swarm over fermenting fruit, especially at latitudes lower than 20°S ( Fig. 1 ), at altitudes below 1000 m (Appendix 1), and near or in dense humid forests. They will enter buildings and kitchens, disturbed habitats and gardens; they are, for example, common in suburban Cairns, Port Moresby, Darwin and Townsville. The abdomens are weakly banded or un-banded (e.g., Figs. 92–96) in both sexes. Only in D. parabipectinata Bock, 1971 ( Christmas Island) and in the dark phenotype of D. ananassae ( Norfolk Island and other South Pacific islands) are the apical abdominal segments dark or blackened (oviscapt pigmentation unknown*). Females are exceedingly difficult to separate in most species. Males can be sorted in an approximate fashion by reference to the sex combs on their fore-tarsi; but confident determination, of dead material, is possible only by dissection or direct observation of male terminalia. Even then, some species remain extremely difficult to identify (e.g., D. ananassae , D. pallidosa and D. anomalata ). But all species are readily cultured in the lab and this opens the possibility for detailed study of sexual behaviour, genotype, karyotype, and other aspects of biology.

1 Male ........................................................................................................................................... 2

—— Female ....................................................................................................................................... 6

2 Tarsomere I of foreleg with sex combs and last abdominal tergite with setae pointing caudally (e.g., Fig. 96) ............................................................................... 3

—— Tarsomere I of foreleg with no sex comb and last abdominal tergite with setae pointing in all directions (e.g., Fig. 95) .................................................................................................................................. D. ironensis

3 Sex combs consisting of two strong and oblique rows of teeth on tarsomere I and a single tooth or two teeth on tarsomere II distally .................................................................................................................. D. bipectinata

—— Sex comb of male consisting of transverse rows of bristles on tarsomere I and II ...................................................................................................................... 4

4 Sex comb consisting of 2 rows of bristles on tarsomere I and 1 row on tarsomere II ................................................................................. D. pseudoananassae

—— Sex comb consisting of 2–6 rows of bristles on tarsomere I and 2–5 rows on tarsomere II ........................................................................................................... 5

Figures

Figure 1. Distribution of 11 of the 12 Drosophila ananassae complex species, the authors have collected at red dot localities or examined specimens collected by others from red circle localities; these data are complete for the Australian Region and incomplete for the Oriental Region. Drosophila lachaisei Tsacas, 1984 from Africa is not shown. The Drosophila pandora sp.nov. type locality is Lake Placid near Cairns (see inset); the D. anomalata sp.nov. type locality is Deeragun near Townsville. Drosophila ananassae s.str. is pantropical within the pale blue lines, the Ambon type locality is shown; D. ananassae extends as far south as Corindi in Australia, it is absent in Sydney and New Zealand. Three or more additional, but undescribed species, occur in New Guinea (and perhaps also in northern Australia), these are not shown. Islands of Torres Strait:(1) Mabuiag, (2) Moa, (3) Thursday, and (4) Mount Adolphus; and localities on Cape York Peninsula: (5) Bamaga, (6) Bertie Creek and Heathlands homestead, (7) Doublemouth and Gunshot Creeks, (8) Gordon Creek, (9) Iron Range (nr airstrip), and (10) upper Peach Creek (McIlwraith Range) are indicated (see inset). Geospatial coordinates of all localities are given in Appendix 1.