Biogeography of bees (Hymenoptera, Apoidea) in Sahara and the Arabian deserts

We discuss the distribution ranges of 57 species of bees (representing 19 genera and 7 sub-families) within a region including, the Sahara and Arabian deserts ind their adjacent areas (SAD). More than 8,000 biogeographical records for a total of 291 species of bees were included in this Study. We calculated several biodiversity indices and show that the study area is characterised by high species diversity (33%) and endemism (58%) rates. Our results show that composition of the SAD fauna results mainly from a "Nearest Neighbour Effect", implying the adjacent areas. However, the influences of more distant areas, like Central Asia and the sub-Saharan region, are also significant, notably in their contribution to species endemism. The comparison of the distributions of the studied species Support the description of diversity hotspots in specific areas: western Atlas (Morocco), eastern Atlas (Tunisia), Tripolitania, Cyrenaica, Nile Valley, Jordan Valley and Oman hills. Five distributional patterns, fitting the ranges of the studied species, are described. The local water availability and the historical cycles of ecological changes in SAD are hypothesised powerful explanatory factors of the observed distributions shapes.