Janus Pannonius Múzeum Évkönyve 38 (1993) (Pécs, 1994)

Természettudományok - Nógrádi, Sára–Uherkovich, Ákos: The Trichoptera fauna of the lake Balaton and its catchment area (Hungary)

A Janus Pannonius Múzeum Évkönyve 38 (1993) 27-45 Pécs, 1994 The Trichoptera fauna of the lake Balaton and its catchment area (Hungary) Sára NÓGRÁDI and Ákos UHERKOVICH NÓGRÁDI, S., UHERKOVICH, Á.: The Trichoptera fauna of the lake Balaton and its catchment area (Hungary). Abstract. On the basis of the literature and unpublished results 118 Trichoptera species are detected from 83 sites of the whole catchment area. 61 of them were collected around the lake Balaton and Kisbalaton, 26 species live only along the upper branches of tributaries of Zala river. First Hungarian data of several species derive from the area examined. Analysis of some biotops and quantitative tables are presented. Introduction The knowledge of the Hungarian Trichoptera fauna was founded by the almost centennial Fauna Regni Hungáriáé (MOCSÁRY 1900). During the first half of this century no new data was given to this data-base. In the fifties, sixties and seventies new results were published by OLÁH (1964, 1967), ÚJHELYI (1971, 1979) and Kiss (1979). In the eighties the authors started to examine the faunistics, systematics and taxonomy of the Hungarian Trichoptera. Thus the number of the known caddisfly species occuring in Hungary and our faunistic knowledge about some regions grew considerably in the last ten years. In spite of these facts, the caddisflies of Balaton Lake, which is the largest lake of Middle Europe, were not known in details. The lake Balaton and its catchment area Balaton is a typical shallow lake with slightly basic water. Its surface is 596 km

2 in average (at average water level), its average depth is 3.25 m. The deepest point is 12.2 m

, nearby Tihany Peninsula. The bottom is covered by fine sand or sandy mud. The shore is edged by reeds and, in several bays, there are large reed-grass assotiations. The water quality of the lake has not degraded during the past years. The most important feeding river is Zala. The catchment area of this river spreads over 2621 km

2

, this is 45.4 % of the total catchment area of Balaton. Other feeding streamlets are the following water-courses: Marót-völgyi-csatorna (18.2 km, 175.9 km

2

) and Zala-Somogy határárok (23.6 km, 264 km

2

). Significant samplings were made at two tributaries of the river Zala: at Szôce streamlet (8.8 km, 32.3 km

2

; see NÓGRÁDI 1987, 1989) and along Szentjakabi-patak (8.2 km, 46.1 km

2

). The total catchment area covers 5774.5 km

2

. The water of Zala river is polluted at Zalaegerszeg. The remaining water courses are moderately polluted. Only the upper branches of the small brooklets are unpolluted. Synopsis of the previous studies MOCSÁR Y (1900) was the first, who listed Trichoptera taxa taken at the lake Balaton, originating from Siófok, (Balaton)kenese, Tapolca etc. In the first half of the recent century BOGA (1936) wrote about caddis larvae of the lake. The data of his paper are based on misidentifications therefore his work is not taken into consideration. After more than three decades UJHELYI (1971, 1982) published new results concerning the Trichoptera fauna of Balaton. The authors of the present paper studied the Trichoptera fauna both of the lake and its catchment area. Some of their results have already been published: Agapetus delicatulus McL., Potamophylax luctuosus Piller et Mitt, and Phacopteryx brevipennis Curt, were listed as new species for the Hungarian fauna by NÓGRÁDI (1984). Later Hydropsy che guttata Pict. was also found (NÓGRÁDI 1984). The paper, which summarized all of known caddfisfly occurences from the South Transdanubia giving several data from the southern parts of the catchment area and from the lake, was published by NÓGRÁDI, UJHELYI and UHERKOVICH (1985). The southern part of Bakony Mts. also belongs to the Balaton catchment area, from where UJHELYI (1979) and the present authors gave several new faunistic data (NÓGRÁDI, UHERKOVICH 1985, UHERKOVICH, NÓGRÁDI 1988). The Hungarian occurence of an interesting species, Hydroptila dampfi Ulmer, was recorded by NÓGRÁDI (1986) from lake Balaton. Limnephilus subcentralis Brauer, as a new species for the Hungarian fauna, was mentioned in an other paper dealing the most southern