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
The third phase is again branded in the sign of muscerda, insofar as it is a dominant four times and a subdominant two times. This phase lasts from the middle of August till the end of September, and is a transitional one from the summer aspect to the autumnal one. In September, H. ruralis and S. dimidiata were dominating on two occ&ciorvs respectively, so that we may call it the muscerda —ruralis —dimidiata aspect to distinguish it from the first muscerda aspect. As was mentioned above, our surveys in 1953 supplied us with valuable data concerning the springtime aspects. At all case, E. bistortata plays an eminent role in April, whilst H. coerulata gains dominancy during May. For the sake of a more exact outline of the spring and autumn aspect changes, however, one ought to dispose of some more surveys. Concerning what was said of the aspects, there emerges an interesting fact. In phytocoenology (and probably for most of the insect orders), other and again other species are characteristical for the several aspects, — but not so with Lepidoptera. The explanation lies in the fact that numerous lepidopterous species have more than one, and equally populous, generations annually ; and primarily those which have high d values. If we study seperately the data of the two lamps functioning simultaneously, we receive characteristical data concerning the dispersion of the several species. As was already stated, the surveys were made in two places alternately, namely at a distance from the constinuous reeds beneath a dense and closed foliage on the one hand, and in the vicinity of the reeds (where the foliage was much rarer) on the other. Collecting technique was, by the way, identical in both places, indeed, we took some care that the lamp be hung always on the identical branch, the same as the sheet in its unvaried place. Accordingly, we may compare our data as two fundamentals, according to the places mentioned and the lamps at a distance of 100—200 m from each other. We have to state, first of all, that the results of the single lamps — of which we have also already spoken — show a considerable difference when compared with each other. At first, we have suspected an inequality in their light-power, but we found out later that even if this were the case, it had but a subordinate importance as one of the causative factors of the differences. If, namely, we compare the data of the two lamps separately and in accordance with the two localities, it will be apparent that the second lamp in the more closed forest site caught but moderately less than the first lamp, whilst in the more open site, its results hardly attained halft h of the total result of the first lamp. Though their results did agree on one occasion in the first site, the second lamp touched 50% of the total of the first lamp on one occasion only in the second site, falling always short of it during the five other surveys. It must be emphasized that we always used the same lamps, and we never changed them. It is our firm belief that these facts will adequately prove that the differences appearing from the results of the surveys were not decidingly caused by the eventual disagreements in the light-power of the lamps, but by the unequal dispersion of the imagos. Any detailed study of the facts tends to strenghten our standpoint. Within the closed forest, Lamp I captured 357 specimens of the dominant species (P. muscerda) on 6 occasions, whilst Lamp II caught 566 during the same 6 surveys. This is a considerable deviation, even when expressed as a ratio of the total results of the two lamps, being 9,5% in the case of the first
