THE PENINSULAR EFFECT IN IBERIAN BUTTERFLIES (LEPIDOPTERA, PAPILIONOIDEA AND HESPERIOIDEA)

A stepwise multiple regression analysis was performed on species densities with a total of 9 physical, geographic and climatic factors for each square. In most taxonomic groups of butterflies, the most important factor determining species density is geography, ie latitude, longitude and distance from the Pyrenees. The result is a marked peninsular effect. The 2nd most important factor is topography, in particular altitude; pluviometric irregularity, annual precipitation and soil type rank 3rd. In Iberian butterflies, as in other lepidopterous groups, there is a clear predominance of species of European origin; number of species of African origin is very small, except in the Anthocharinae. -from Authors