Systematics and biogeography of southwest Pacific Bactrocera (Diptera : Tephritidae : Dacini)

This study reports the results of a phylogenetic analysis of 30 Pacific Bac trocera species. These 30 species belong to three subgenera - Bactrocera, B ulladacus and Notodacus. Bactrocera and Notodacus were reported by Michaux (1996) to be basal members of a monophyletic group of Dacini subgenera. Six species belonging to four other subgenera (Afrodacus, Zeugodacus, Parazeug odacus, and Sinodacus), while being part of the Dacini fauna of the southwe st Pacific, were excluded because they are not members of the Bactrocera-No todacus group (Michaux, 1996). Initially 214 minimal trees were obtained fr om an analysis using PAUP. Successive approximations weighting of character s to maximise the Rescaled Consistency and Retention Indices resulted in th e same subset of three preferred trees. The strict consensus tree showed th at informal species complexes previously recognised within Pacific and Aust ralasian Bactrocera are not natural groupings. A supra-specific classificat ion of Bactrocera, in which a number of subgenera are recognised, is broadl y supported. The subgenera Bulladacus and Notodacus are monophyletic. The b iogeographic analysis of Pacific Bactrocera was based on the strict consens us tree and is interpreted in terms of the tectonic development of the regi on, with particular reference to the fragmentation of east Gondwana. The ne ed for a centralised database of Pacific taxa is discussed. (C) 1999 Elsevi er Science B.V. All rights reserved.