Global Patterns of Termite Diversity

Abstract

What is known of termite global diversity patterns is reviewed at a number of spatial scales (from < 1 ha to worldwide), with the caveat that data arc, at present, rather sparse. Local species richness and regional generic richness arc strongly influenced by habitat, altitude and climate, with the highest diversity of termites found in wet lowland tropical forests. However, historical asymmetrical latitudinal and longitudinal (inter-tropical) gradients are perhaps as important in influencing diversity patterns. Increased latitude (from the equator) leads to a rapid drop in diversity; however, this drop is asymmetrical, with southern latitudes having significantly higher generic richnesses than northern ones in the same latitudinal position. An asymmetry also exists in diversity between the main tropical forest blocks, with (in diversity terms) Afrotropics > Ncotropics > Oriental tropics. This contradicts the predictions of energy-diversity theory. Both of these gradients can be described as "diversity anomalies". Multivariate analyses of generic WORLDMAP data are reviewed showing that the latitudinal and longitudinal diversity anomalies arc due to the differential distribution of termite clades in different biogeographical regions, rather than a uniform difference across all clades between regions with different diversities. Different clades may, therefore, have evolved in different areas due to particular idiosyncratic events across geological time, and then may not have dispersed significantly from their original biogeographical regions. Indeed, the limited data that arc available suggest that termites arc generally poor dispcrscrs across geographical barriers. The present, admittedly incomplete data, suggest that the families of termites may have evolved on Pangaea prior to the break-up of that super- continent, and that the major clades of the Tcrmitidac may have evolved subsequently on the separate pieces. The characteristics of the termite fauna of the different regions arc discussed, as well as the distribution of genera within the putative clades, Termites appear to represent a very good example of a group whose biology and ecology are strongly influenced by history. Some possible consequences of these historical constraints on ecological processes are briefly discussed. 1.