Full-text - Norsk entomologisk forening

area, Torne Lappmark (Tjeder 1978). ExceptT. (S.) pagana and T. (P.) middendorffi thespecies found at Dovrefjell were includedalso in the Swedish investigations mentionedabove. T. (V.) excisa, T. (S.) invenusta, T.(S.) subnodicornis and T. (S.) grisescens hadnearly similar flight periods at Dovrefjellmountains and the low/middle alpine zone atFinse in the northern part of Hardangervidda,South Norway (Hofsvang 1974).Therefore, in the Scandinavian mountainsfrom Hardangervidda, South Norway to Abisko,Torne Lappmark, the flight periods ofthe tipulid species do not deviate much.The species of Tipulidae reported in thepresent study are found within the previouslyknown distribution area in Norway except T.(S.) pagana. T. (P.) middendorffi and N.lundbecki. T. pagana was earlier only knownfrom the Oslo area in Norway, but is recordednorth to Angermanland in Sweden (Tjeder1955). T. (P.) middendorffi a boreal speciesand previously known from USSR east ofArkhangelsk (Theowald 1980), is reportednew to Fennoscandia. N. lundbecki was earlierreported from North Norway (Mannheims1951).Of the 15 species collected from the Dovrefjellmountains, six species, T. (V.) excisa, T.(V.) montana, T. (S.) gimmerthali, T. (S.)limbata, T. (S.) subnodicornis and T. (S.)grisescens, show a boreoalpine disjunct distribution(Theowald & Oosterbroek 1985),which means that they are recorded in thecontinental European Alps and in the Scandinavianmountains. Five species have a borealdistribution, T. (A.) salicetorum, T. (V.)laccata, T. (S.) invenusta, T. (P.) middendorffiand N. lundbecki. With the exceptionof T. (S.) in venusta, these boreal species belongto a group of species with a mainly easternPalaearctic distribution (Theowald &Oosterbroek 1985). T. (V.) nubeculosa, T.(S.) pagana, T. (P.) melanoceros and P. subserricornisare distributed in Northern Europe,but they are also a part of the tipulidfauna of the deciduous forests of the westernand middle part of the European lowland(Theowald & Oosterbroek 1983).Considering the number of specimenscaught during 1980 to 19835 species, T. (A.)salicetorum, T. (V.) excisa, T. (S.) gimmerthali,T. (S.) in venusta and T. (S.) subnodicornismay be regarded as common of fairlycommon in the Dovrefjell National Park. Allof these common species, except T. (A.) salicetorum,were found in more than half of thenumber of localities sampled. T. (A.) salicetorumoccurred in two traps only, at Kallvellaand Stropla, and may set strong requirementsto the habitat, but be locally abundant.Six species, T. (V.) laccata, T. (V.) nubeculosa,T. (S.) pagana, T. (S.) grisescens, N.lundbecki and P. subserricornis must be regardedas rare in Dovrefjell National Parkbecause they were only recorded at one localityand with one individual only. T. (A.)salicetorum and T. (P.) middendorffi werecollected at two sites and on the western sideonly. The collections indicate that they havea restricted distribution in the area. T. (V.)montana was caught at the 4 highest collectingsites only. T. (S.) gimmerthali, T. (S.)limbata and T. (P.) melanoceros were recordedup to about 1200 m a.s.l. From tab. 2 itmay look like that they are distributed onlyon the eastern side of the valley. This may bean artefact because ofthe collecting sites chosen.However, it is known from caddis-flies(Trichoptera) that great differences in speciescomposition occur between the eastern andwestern side of River Driva (Solem 1985).The caddisfly Apatania muliebris McLachlanwas dominant in the streams Blesbekken andRaubekken on the eastern side, but only scatteredindividuals were found on the westernside. The differences found in geology, plantspecies and pH values between the eastern(range 7.3 to 7.9) and the western side (range6.0 to 6.8) of the valley, may be reflected alsoin the species composition ofthe tipulids, butthe present study does not give conclusiveanswears to this.T. (V.) excisa on the other hand, was commonat all sites and all hight levels in thealpine zone on the eastern and the westernside of the valley, and live in habitats rich inorganic matter and in the present study havepH values between 6.0 to 7.9 T. (S.) invenustashowed a similar range in habitat preferencesas T. (V.) excisa. Most tipulid larvaeare detrital feeders (Byers 1984) and theirecological importance must be substantial inalpine areas. However, since tipulid larvaeand adults are relatively large insects theirecological importance as food for other invertebrates,birds and mammals is probablyeven greater.55