S. Mahunka szerk.: Folia Entomologica Hungarica 57. (Budapest, 1996)

Table 29 (continued) Species 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 z Sepsisfulgens 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 A Uotrichoma filiforme 0 1 0 1 1 0 3 0 0 1 0 1 0 0 0 0 8 Alloirichoma laterale 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 Psilafta nigrilella 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 I Hydrellia griseola 1 2 1 1 2 0 3 1 0 5 4 2 0 0 0 0 22 Coproica vagans 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 Elachisoma alerrimum 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 Spelohia czizeki 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 Leptometopa niveipennis 2 3 2 5 4 1 4 6 20 0 11 7 2 0 0 0 67 Meoneura flavifacies 1 2 1 1 u 0 3 0 5 0 ] 1 0 0 0 0 15 Meoneura neglecla 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 l'elomyiella mallochi 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 Telhina ezernyi 0 1 1 1 1 0 0 0 0 2 0 1 0 0 0 0 7 Liriomyza sp. 0 1 0 0 0 0 1 0 0 0 1 0 0 0 0 0 3 Oscinimorpha alhisetosa 3 3 1 2 2 0 1 1 0 6 5 4 0 0 0 0 28 Oscinella frit I 3 1 0 3 1 0 1 0 1 1 1 0 0 1 0 14 Incertella alhipalpis 0 1 2 1 1 0 0 1 0 2 6 2 0 0 0 0 16 A phanotrigonum fascie/la 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 Aphanolrigonum femorella 0 0 0 0 0 0 0 0 0 7 0 0 0 0 0 0 7 Meromyza sp. 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 Chioropidae indet 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 Adia cinerella 1 1 2 1 2 1 1 1 0 1 3 1 0 1 0 0 16 Delia platura 2 5 0 5 1 0 1 2 0 1 3 2 1 1 0 0 24 Anthomyiidae indet 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 l.ispe melalenca 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 Lucilla sericata 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 I'ollenia spp. 0 2 0 0 1 0 0 0 0 0 1 0 0 0 0 0 4 Senolainia conica 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 Tachinidae sp.6. (small) 0 0 0 0 0 0 1 0 0 0 0 o 0 0 0 0 1 Meigenia mulahilis 8 8 7 7 0 1 9 4 4 1 3 ; 2 ; 1 70 47 species 34 51 33 47 a: 3 27 38 29 75 70 51 7 9 2 5 524 DISCUSSION No doubt that the pan-traps which are lighter than the ground with glittering water surface had some attractive effect on the good flying flies like the anthomyiid Adia cinerella, Delia platura and some tachinid flies; consequently, we caught more specimens than their true ratio in dipterous communities of the pastures, or those abundance ratios which would touch down to the ground proportionally. But small flies and other small insects are unable to control their landing and so we can accept their numbers as realistic, landed on 0.1% of the area of sheep-run sampled; that is, the numbers found are not higher than expected for the intermediate (non-trap) areas for a majority of the species. Considering the circumstances — first of all as regards the barren outlook of the Hungarian "puszta" in early summer — we think it remarkable that we might expect as many as 2000 dipterous specimens to land on 16x0.1 m

2 area in three hours. Pan-traps with detergent water are a proper device to demonstrate the movement of the unexpectedly high number of insects, which occur or live on the seemingly "empty" sheep-runs. As for the difficulties in judging the community relationships of flying insects we must quote C. B. Williams' (1950) classical paper: "...with animals it is easy to define an individual, but often difficult to say to which particular area it belongs; whereas with plants it is often difficult to define an individual but easy to say where it is growing". Indeed, a part of the populations detected are those which are coprophagous or at least which are attracted by the sheep-droppings (for the flies developing in sheep-droppings see Papp (1985); some others are autochthonous, developing in grasses, in grassroots, or which are terricolous (saprophagous or feeding on soil algae, etc.). However, a very high number of those species was also found, which — considering their known life habits — are not attached to sheep-runs; the air current drives them there by chance