Somogyi Múzeumok Közleményei 13. (1998)

Farkas S. 1998: A Rinya-ártér Isopoda faunája I.Bakháza

262 The Isopod fauna of the Riny FARKAS In 1996 pitfall samples were taken from several locations in the Rinya region including the grazing lands and woods in the surroundings of the village Bakháza. The main questions of the survey were: (1.) which isopod species live in the studied area; (2) is there any difference between the isopod assemblages of different habitats; (3) how does the population size and sex ratio of the dominant species change over time. The traps collected 2719 Isopoda specimens which belonged to 7 species: Ligidium hypnorum (Cuvier, 1792), Hyloniscus riparius (C.L. Koch 1838), Trachelipus rathkei (Brandt, 1833), Trachelipus nodulosus (C.L. Koch 1838), Porcellio scaber Latreille, 1804, Porcellium collicola (Verhoeff, 1907) and Armadillidium vulgare (Latreille, 1804). 99.5 % of the collected material belonged to A szerző címe (Author's address): Dr. Farkas Sándor Janus Pannonius Tudományegyetem Ökológia és Állatföldrajzi Tanszék H-7624 Pécs, Ifjúság u. 6. a region I. Bakháza (Hungary) SÁNDOR three species: T. nodulosus, P. collicola and A. vulgare. The traps were situated in three different habitat: grazing land, Prunus spinosa bush and Robinia pseudoacacia wood. Traps set in grazing land caught all of the species except P. scaber, but the number of trapped individuals was very low. T. nodulosus was the dominant species here (75%). Traps in P. spinosa bush collected isopods in the highest number. P. collicola was the dominant species of this habitat (74.5%), subdominant species were T. nodulosus (9.13%) and A. vulgare (16.3%). In the false acacia wood A. vulgare had the highest proportion (50.29%). Seasonal changes in population size of the three dominant species did not differ from other paper's data. The sex ratio of these species were strongly female biased (70-100 %).