Butterfly diversity and a preliminary comparison with bird and mammal diversity

Abstract

Butterflies are among the best-known insects•an estimated 90% of the world's species have scientific names. As a consequence, their biology has been extensively investigated (Vane-Wright and Ackery, 1984), and they are perhaps the best group of insects for examining patterns of terrestrial biotic diversity and distribution. Butterflies also have a favorable image with the general public. Hence, they are an excellent group for communicating information on science and conservation issues such as diversity. Perhaps the aspect of butterfly diversity that has received the most attention over the last century is the striking difference in species richness between tropical and temperate regions. For example, Bates (1875) wrote that it would convey some idea of the diversity of butterflies (in the neighborhood of Belem, a town near the mouth of the Amazon River) when he mentioned that about 700 species are found within a hour's walk of the town, whereas the total number found in the British Islands does not exceed 66, and the whole of Europe supports only 321. This early comparison of tropical and temperate butterfly richness has been well-confirmed (e.g., Owen, 1971; Scriber, 1973). A general theory of diversity would have to predict not only this difference between temperate and tropical zones, but also patterns within each region, and how these patterns vary among different animal and plant groups. However, for butterflies, variation of species richness within temperate or tropical regions, rather than between them, is poorly understood. Indeed, comparisons of numbers of species among the Amazon basin, tropical Asia, and Africa are still mostly personal communication citations, even for vertebrates (Gentry, 1988a). In