Drosophila nukea Magnacca

Magnacca, Karl N. & Price, Donald K., 2012, New species of Hawaiian picture wing Drosophila (Diptera: Drosophilidae), with a key to species, Zootaxa 3188, pp. 1-30 : 19-20

Drosophila nukea Magnacca , new species

Fig. 5

Diagnosis. Among the hawaiiensis subgroup, this species is most similar to D. gradata of O‘ahu and D. hawaiiensis of Hawai‘i due to lacking cilia on the tibia. It is readily distinguished from both of those by the completely dark mesonotum and scutellum; at least the scutellum, and usually the posterior mesonotum, is pale brown in the other two species.

Description. Male. Head. Front brown, yellowish near the frontal suture; ocellar triangle and orbits dark brown pollinose. Fronto-orbital setae normal, anterior reclinate about half as long as the proclinate and posterior reclinate. Face bright white, gena pale yellow except for a small dark brown spot below the eye. Antenna dark brown; arista with about 5–6 dorsal rays in addition to the apical fork (ventral rays mostly broken in holotype), and a few long median branches. Two strong oral vibrissae, other oral setulae smaller and hairlike. Palp brown, narrow and elongate, broadest near middle, rounded apically, with a single thin apical seta, slightly shorter than palp. Labellum and mentum brown. Thorax. Mesonotum and scutellum entirely brown, with conspicuous gray pollinose medially and along the dorsocentral row. Humeri yellow medially in a stripe between the humeral setae, brown above and below. Pleura entirely brown. Two pairs of strong dorsocentral setae, the anterior about 4/5 as long as the posterior. Legs. Predominantly yellow, tinged with brown on all coxae and apices of all femora. Front tibia lacking cilia, front basitarsus densely covered with about 20 long dorsal cilia in irregular rows, longest at the base, becoming slightly shorter apically; second segment with about five cilia, remaining segments bare. Wings. Subbasal spot relatively large, extending into cell R5, but not reaching r-m crossvein. A continuous band present across middle of wing, nearly parallel-sided, slightly broadened at anterior margin. Marks at apices of R2+3, R4+5, and M confluent. Costal fringe extending about 2/3 the distance between apex of R2+3 and R4+5. Abdomen. Each segment with a pair of large yellow spots anterodorsally, remainder dark brown. Cerci slightly higher than long, yellow-brown. The genitalia have been dissected and appear to resemble D. gradata in having a depression beyond the preapical protuberance of the aedeagus and a distinct bend in the paramere near the apex, but they have dried in the vial and may be distorted.

Female. Unknown.

Types. Moloka‘i: Holotype 3, So. Hanalilolilo, 3.iii.1966, J. P. Murphy (genitalia in a glass vial mounted on same pin) (UHIM)

Distribution and ecology. Moloka‘i, in wet forests (but see Discussion). Host unknown; appears to be most closely related to species breeding in sap fluxes of Acacia koa ( koa , Fabaceae ), but this tree does not appear to live in the area where it was collected.

Etymology. From the Hawaiian n ū kea, white-beaked or white-mouthed, a reference to the white face which contrasts against the dark coloration of the rest of the body.

Discussion. Given the relative abundance of D. gradata and D. hawaiiensis on O‘ahu and Hawai‘i respectively, and the number of other species in this subgroup found on Maui, it is surprising that more specimens do not exist. However, koa is absent from the forest in the area where it was collected. The specimen may therefore be a vagrant from the drier, lower-elevation areas where koa occurs. Another species in this complex, D. musaphilia of Kaua‘i, is also rare despite an abundance of koa .

Figures

FIGURE 5. Drosophila nukea. A. Right front leg of male, anterior view. B. Wing.