EXPERIMENTAL SYSTEMATICS AND ECOLOGY OF DROSOPHILA

At the urging of Woodworth in 1900-1901, Castle began laboratory experiments with Drosophila melanogaster, then known as D. ampelophila (21). These studies led to investigations by Lutz (49) and especially by Morgan (21), thereby establishing Drosophila as prime organisms for the study of genetics and evolution. With worldwide interest focused on Drosophila melanogaster as an experimental organism, interest in the systematics and ecology of the genus and also the family Drosophilidae was stimulated. During the period 1820-1900, 112 species of Drosophila were described. Of these 52 are still considered to be valid members of the genus. In comparison, from 1900-1970 more than 1100 valid species were described and probably an additional 600-800 species are yet to be collected (96). Currently Basden (2) is preparing a catalog of the world's Drosophilidae which will contain every record of speciation, biology, and systematics relating to Drosophila and its allies. The genus is worldwide in distribution, with the majority of the species tropical or semitropical. In colder areas, i.e. mountain masses and the Arctic regions, only a few species are to be found (3, 7, 97). Thus, Alaska (586,400 sq mi) has only 9 species, while El Salvador (8260 sq mi) has at least 120 species, and Hawaii (6435 sq mi) more than 400 species. Eight species (D. ananassae, buskii, funebris, hydei, immigrans, melanogaster, repleta, and simulans) are cosmopolitan and have achieved their distribution by being inquilines of man.