MICRODISTRIBUTION OF BUTTERFLIES IN A MOSAIC-LIKE HABITAT - THE ROLE OF NECTAR SOURCES

The microdistribution of five butterfly species through their flying s eason was analyzed in a mosaic-like habitat, brought about by secondar y succession. In order to explain the patterns observed, activity patt erns and the use and distribution of nectar sources were determined. E mphasis Was laid on the changing allocation of visits to flower specie s and changing abundances of flowers during the season. The use of nec tar sources was basically limited to three flower species, Centaurea s cabiosa, C. bracteata and Serratula tinctoria. As a consequence, niche breadth values were generally low and niche overlaps generally high. Some butterflies changed their patterns of flower visits during the se ason and therefore reduced niche overlap with the other butterfly spec ies. The microdistribution of Melanargia galanthea, Lysandra coridon, Ochlodes venatus and Lictoria achilleae was strongly influenced by the distribution of their preferred nectar sources as well as by areas ge nerally rich in flowers. Changing flower preferences of Melanargia gal athea and Lysandra coridon males during the course of the season were also expressed by changes in the correlations between the distribution of these butterflies and their nectar plants. The distribution of nec tar sources was not found to be of importance for Coenonympha arcania, a species which rarely visited flowers.