Les Drosophilidae (Diptera) de l‘Ile de La Réunion et de l‘Ile Maurice. III. Biologie et origine des espèces.

Abstract

30 Drosophilid species are now recorded from Maskarene Islands. In Reunion the dominant species is Drosophila simulans (more than 30% of the collected flies), while it seems to be absent from Mauritius, being replaced there by the endemic vicariant Drosophila mauritiana. In Reunion altitude and to a lesser degree pluviometry are the two decisive factors determining the repartition of the different species. Maskarene Islands contain about 30% of endemic and the same proportion of cosmopolitan species. The remainder of the fauna consists of Etiopian and Oriental elements. The number of endemic species proves that in many cases the introduction of flies was a very old event, much before human colonization. The same conclusion may probably apply to some cosmopolitan species. The role of man in the dispersion of drosophilid flies is probably far less important than usually admitted.