Frontiers of Biogeography

Biogeography attempts to find explanations for the distributions of species, based on their past histories and present environmental conditions. Historically, biogeographic studies were modelled on intuitive and expert knowledge, whereas recent studies have advanced with the aid of digitised natural history collections, computational power and repeatable methods. In South Africa, biogeographical studies on insects are greatly lacking and very little is known about the zoogeographic patterns for many insect groups in the region. South Africa has a high level of diversity and endemism of orthopterans (> 800 species), making them an ideal group to investigate zoogeographic patterns. The aim of this study was to identify and describe the zoogeographical patterns of South Africa’s orthopteran species, based on the distributions and levels of diversity of all major families. Point locality data was used to conduct a hierarchical cluster analysis based on the shared presence of species to delimit zoogeographical centres. In addition, delimited centres were compared to plant-based biomes and phytogeographic regions. Results showed that orthopteran species richness was evenly distributed across the region and clustered into six zoogeographical centres. There was a primary split, separating species into a western winter-rainfall and an eastern summer-rainfall group. The western and eastern regions contained three centres each, with the east being less diverse and taxonomically distinctive than the west. Strong consensus was seen between orthopterans and the Greater Cape Floristic Region, and between orthopterans and the Cape zoogeographic region for butterflies, reinforcing the notion that this region is representative of a biochorion. In addition, this region had the greatest numbers of orthopteran families, highlighting its importance for orthopteran diversification.