Boros István (szerk.): A Magyar Természettudományi Múzeum évkönyve 51. (Budapest 1959)

Kovács, L. ; Gozmány, L.: Data to the quantitative relations of the Lepidoptera of the Alderwood Marshes in Ócsa, Hungary

being substituted by Galium aparine, Urtica dioica, Ballota nigra, Phragmites communis, various Carex species and other plants. Near the eastern border of the forest, there are smaller and larger reedy patches in a narrow depression, probably the earlier bed of a stream. In deeper sites, this bed will broaden to create open areas among the trees. Among the reeds, Urtica dioica and Calystegia sepium abound. Lichens and algae are also very abundant on tree-trunks and in the reeds. — We were successful to find, in the majority of cases, the foodplants of the Lepidoptera species observed, especially of those with large individual numbers. Our surveys were made by the use of kerosene gas lamps of a strong (300 candlepower) light. The lamps were hung on branches, possibly low (about 1 and a half m) above the ground level to eliminate as far as possible the onflight of specimens from neighbouring plant associations. There was a sheet set up behind the lamp. Moths which did not alight on the sheet were gathered partly by nets, partly shaken down from the branches and/or the trunks, and killed in cyanide bottles. Their total amount, as of the single occasions, was not more than 2—5% of the whole result. Light traps were not used on account of the consideration that they had had also required our presence to obviate the above losses, and because the animals, especially the small moths, will become utterly unrecognizable in them. We also experimented by a parallel baiting method, but this method was not fruitful in this area, and though we affixed the strings of apple-baits so far from the light of the lamps that they were in complete darkness, still there appeared but single specimens (in the strict sense of the word) on them during the whole night. With regard to the fact that the imagos of many Lepidoptera are shortlived, we endeavoured to repeat the surveys as often as possible. From 10 June till 18 September, we visited the research area 14 times, weekly between 1 July and 2 September. The surveys continued from dusk till dawn, with the exception of 15 July, when, owing to a sudden squall, we had to dismount the lamps at 0030. For the sake of studying also dispersion, there were always 2 lamps in use, with the exception of 1 July and 18 September. The surveys were made alternately in the dense forest or/and in more open spaces, around the ready patches. We affixed the lamps, however, in always identical circumstances in the selected points. There was a special control lamp in action on 6 occasions, on which the material was collected by J. S z ő c s. The work of the surveys resulting from the stable lamps were done by the authors, with the collaboration of E. D r ó z d y and M. Glaser, preparatresses. We have listed the materials, especially the mass-species, in situ, pinning only those, with the exception of specimens unidentifiable on the spot, which were needed for the collection of the Museum, casting off all other animals. It is well-known that the method of collecting by light is a selective method. There are certain Lepidoptera species which will almost never fly onto an artificial source of light, and there are again others which, though visiting it, their numbers appearing on it will be but a slight fraction of their individual numbers in reality. One may easily find this out if the surveys are made by lamping and by a parallel baiting. This phenomenon was several times observed also in ócsa, but we have ascertained of one species only that a few of its specimens will visit the lamp though its individual number is very high. This is Euphya