Relationships between the geographic distribution of phytophagous insects and different types of vegetation: A case study of the flea beetle genus Chaetocnema (Coleoptera: Chrysomelidae) in the Afrotropical region

摘要

This study analyses the geographic distributions of 95 endemic and sub-endemic species of Chaetocnema (Coleoptera: Chrysomelidae) found in Sub-Saharan Africa and Madagascar, in order to compare and correlate their pattern of the geographic range (chorotype) and the distribution of terrestrial ecosystems in Africa and Madagascar. The data compiled for the species of Chaetocnema are based on records for 1639 collecting localities. Most of the species of Chaetocnema have restricted geographical ranges (67.3%), whereas relatively few species (11.6%) are very widely distributed. The latitudinal and longitudinal gradients in the numbers of species reveal that the highest levels of species richness occur in the Equatorial Belt and Southern Africa. Species of Chaetocnema in Sub-Saharan Africa have a clear preference for grassland and the wide-open environment associated with savannah. However, forest ecosystems are also important for numerous species, particularly in Madagascar. Several endemic species are associated with the Mediterranean vegetation in the southern part of West Africa. Species of Chaetocnema are generally associated with a limited number of vegetation types within the Afrotropical region. A cluster analysis based on calculating the squared Euclidean distance and using the WARD clustering method revealed a significant correlation between the chorotype and the vegetation types associated with each species. Finally, certain species of Chaetocnema that are characteristic of specific types of vegetation and/or indicators of biodiversity hotspots in Sub-Saharan Africa and Madagascar are highlighted.