Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 83. (Budapest 1991)

Korsós, Z.: Abundance and seasonal activity of millipedes in a dolomitic grassland community (Diplopoda)

grassland communities. In the hot summer months, air temperature can reach 50 °C, and the thin, low vegetation provides little protection against drought. Millipedes, searching for moisture, hide down into the soil and among the dolomite rock fragments for summer aestivation. The situation has already been shown several times: diplopods of the temperate region usually have bimodal yearly activities (GEOFFROY 1981). Besides the spring and autumn activity peaks and the complete winter hibernation, there is usually a low summer activity period. Interestingly enough, in some cases, even winter activity has been proved for millipedes under the snow layer (MERRIAM, WEGNER & CALDWELL 1983). BARLOW (1958) found Cylindroiulus latestriatus {=frisius) to be active in March-May and September-November. VOIGTLÄNDER (1987) stated the same for Enantiulus nanus and Kryphioiulus (=Allajulus) occultus. HORNUNG (1990) during her long-term study of the Diplopoda and Isopoda communities in a sodic grassland in Hungary, also found a summer resting period in Megaphyllum unilineatum. As regards Kryphioiulus occultus, the early decline of activity at the beginning of June, found on the Odvas Hill, can be explained again by the narrow ecological tolerance of that species. Pitfall trapping is not a satisfactory method for estimating population size. Despite that, the larger number of captured females and the appearance of the juvenile specimens must be due to a larger abundance. However, the lack of the specimens in the pitfall traps during summer is due to the low activity of the millipedes as soil-dwelling animals (BAKER 1979,1985, HORNUNG 1990). One aim of the further studies could be a detailed investigation on the population dynamics and life history of both species. The relationship between the environmental factors and the millipedes can also be subject to subsequent examinations. * * * Acknowledgements -1 would like to thank DR. GY. SZÉL for his valuable help in field work, I. FÜRJES and Sz RÓKA for sorting out the material, and DR. CS. MoSKÁt for his untiring encouragement, without whom this paper would have never been completed. This study was made within the framework of the Succession Research Project", an OKKFT programme of the Hungarian Natural History Museum supported by the OMFB. References BAKER, G. H. (1979): The activity patterns of Ommatoiulus moreletii (Diplopoda: Julidae) in South Australia. -/ Zool London 188:173-183. BAKER, G. H. (1985): Diplopoda of a dry sclerophyllous woodland (Eucalyptus obliqua - E. baxteri) in the Mount Lofty Ranges, South Australia. - In: GREENSLADE, P. & MAJER, J. D. (eds): Soil and litter invertebrates of Australian mediterranean-type ecosystems. WALT School of Biology Bulletin, No. 12, p. 54-56. BARLOW, C. A, (1958): Distribution and seasonal activity in three species of diplopods. - Arch. Néderl Zool 13: 108-133. BLOWER, J. G. (1956): Some relations between millipedes and the soil. - Sixième Congrès de la Science du Sol, Paris, p. 169-176. D UNGER, W. & STEINMETZGER, K. (1981): Ökologische Untersuchungen an Diplopoden einer Rasen-WaldCatena im Thüringer Kalkgebiet. - Zool Jb. Syst. 108: 519-533. GEOFFROY, J.-J. (1981): Étude d'un écosystème forestier mixte V - Traits généraux du peuplement de Diplopodes édaphiques. - Rev. Écol Biol. Sol 18: 357-372. HORNUNG, E. (1990): Ecological studies on Megaphyllum unilineatum (Diplopoda) on a sodic grassland (South-Hungary). - Abstracts of the 8th Int Cong. Myr, Veröff. Univ. Innsbruck, No. 177.