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

middle of August. In the Hanság, the very same species appeared in the highest numbers, but the dominancv values of the several species were again not coincident with those established for ócsa in the same period in 1952. Curiously, the second generation, of P. muscerda was on the wing in great numbers already on 14, 15 July, having been condominant with the second generation of E. bistortata which, in the previous year in Ócsa, took the third and fourth places together with H. rostralis in the same period. The subdominant species were E. griseola and Ae., punctulata, of which two latter had almost finished with its flight in the alderwood marshes of Ócsa in the previous year. During the surveys in August, the lamp was working faultlessly unfortunately on the second day only, on 12 August. At that time, E. griseola came to the fore, P. muscerda having been thrust to the second place. Far behind, H. proboscidalis brought up the rear. Though there were indubitable shifts in the dominancy relations also at that time, as related to the situation in Ócsa in 1952, it is beyond dispute that the species with the highest individual numbers are identical in both places. By the help of the surveys in the Hanság, it was possible to establish that not only do the lepidoptera communities of our alderwood marshes even at a large distance from each other concur in essentials, but also that there are differring elements among the species of low d values. In Ócsa, we met with some species characteristical of the sandy areas of the Plains, not occurring in the Hanság. Such, among others, were Caradrina terrea Frr., Criphia strigula Bkh., etc. On the other hand, we captured species in the Hanság which may, in Hungary, be found only in the western part of the Transdanubium or, eventually, in mountainous districts. To mention but a few, Cerura bicuspis Bkh. Xantorrhoë biriviata Bkh., Ecliptoptera capitata H.

—Sch., etc. Finally, we may point it out that the majority of the species occurring in masses in our alderwood marshes will occur in high individual numbers not only in swamps of the above nature but also in other plant associations and generally in forests of a wet character. There are, however, three species among them which, though observable in different kinds of plant associations, occur in masses in alderwood marshes only. They are P. muscerda, E. griseola and C. pusaria. The mass-occurrence of C. pusaria will indubitably be explained by the fact that its main and (in Hungary) almost exclusive foodplant is the alder. It is very interesting that it was never yet a dominant species during our surveys. It can be observed also in more open places, e. g., along streams bordered by alder trees, though in more moderate numbers. The situation concerning the former two species is different. According to literature data, they live on lichens and mosses, indeed, some observations claim that the larvae of muscerda feed also on dry litter. As far therefore as the nature of their food is concerned, it does not bind them to the alderwood marshes and, as a matter of fact, we have found them in localities where there were no aldertrees at all. The fact that they can be observed in masses only in alderwood marshes will surely be determined by other circumstances, namely by the special oecological conditions of these forests. These seem to be primarily the high humidity content of the atmosphere, combined by the almost total absence of direct sunshine and a moderate daily fluctuation in temperature. On the basis of the above discussion it cannot be doubted that one may receive characteristical data relating to mass conditions of phototropic lepi-