Biogeography and ecology of the ant fauna of Madagascar (Hymenoptera: Formicidae)

Abstract

In the Malagasy region, 52 ant genera have been recorded, of which 48 are estimated to be indigenous. On the island of Madagascar, 41 out of 45 recorded genera are considered to be indigenous. Four genera are endemic to Madagascar and one to Mauritius. Currently, there are 383 names of described species-group taxa from the Malagasy region, and 320 from Madagascar. The level of endemism is high at the species level, >90%. The ant fauna of the Malagasy region, however, is poorly understood; an estimated two thirds of the ant species are undescribed. The diversity of ant genera on the island is comparable to that of other biogeographic regions. On the basis of generic and species level comparisons, the Malagasy fauna shows greater affinities to the Afrotropical region than to peninsular India and the Oriental region. The distinct gaps in the taxonomic and ecological composition of the fauna of Madagascar are evaluated in the context of island radiations and relict taxa. The absence of driver ants in Madagascar may have spurred the diversification of Cerapachyinae and may have permitted the persistence of other relict taxa such as the Amblyoponini.