Is Drosophila nasuta Lamb (Diptera, Drosophilidae) currently reaching the status of a cosmopolitan species?

Abstract

ABSTRACT In early March 2015, three males and two females of one unknown species of Drosophila were collected from a compost pile and some garbage cans in the west region of the city of São Paulo, state of São Paulo, Brazil. Morphologically it is easily identified by the presence of the following conspicuous features: a brownish dorsal stripe along pleura, an entirely iridescent silvery-whitish frons when seen directly from the front, and a row of cuneiform setae on anteroventral side of femur of foreleg; the former two traits being more evident in males. The species was easily reared in a modified banana-agar medium and two isofemale lines were established allowing to obtain mitotic cells showing a diploid chromosome number of 2n = 8. Based both on morphological and chromosomal features, in addition to the geographical distribution, we concluded that the unknown flies belong to Drosophila nasuta Lamb, 1914, a tropical species of the nasuta subgroup of the Drosophila immigrans species group. Photomicrographs of male imagines, terminalia, mitotic and meiotic metaphase plates, as well as of female mitotic metaphase, are included.

Keywords

• Karyotypes
• Immigrans group
• Invasive species
• Nasuta subgroup
• Terminalia