AQUATIC MACRO-INVERTEBRATE FAUNA OF CAVES OF SAMEGRELO-ZEMO SVANETI AND IMERETI, WESTERN GEORGIA, CAUCASUS: TROGLOBIOTIC AND EPIGEAN SPECIES COMPLEXES

The fauna of cave-dwelling aquatic macro-invertebrates in western Georgia has been very poorly studied. Only few papers have been devoted to the taxonomy of individual groups of cavernicolous organisms. In addition, no analysis of the structure of aquatic assemblages has ever been attempted. The present work describes the invertebrate fauna of five caves of western Georgia, the checklist comprising 17 species of troglobionts with 11 new species to be described elsewhere. Troglophiles and trogloxenes include eight species each. Two main types of ecofaunistic complexes have been revealed in the caves. The first complex is troglobionts, the second one comprises epigean macro-invertebrates and is composed of two ecological variants: rheophilic and xylophilic. The latter variant has been observed only in the Kumistavi Cave which is equipped for tourist visits. The remains of wood construction material caught in cave rivers and creeks are occupied by trogloxenic insects. Both artificial illumination and exogenous material brought inside from the surface render the anthropogenic impact that helps epigean amphibiotic insect larvae colonize subterranean habitats. The compositions of troglobionts from different caves overlap for an average of 25% of the total number of species, the lists of troglophiles shared 75% species, while the trogloxenes are completely specific to each cavity. The total fauna of aquatic invertebrates differs greatly between the caves, even when these were located at a distance of 10-20 km from each other.