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)

DISCUSSION The difference in abundance of the two species is probably due to the greater ecological tolerance of Megaphyllum unilineatum. Based on literature data (SCHUBART 1934), this species occurs in almost every kind of biotopes. Since millipedes usually prefer rather moist microhabitats, Megaphyllum unilineatum having a broad tolerance for environmental conditions often becomes dominant on drier places. In Hungary, it is a common inhabitant of sandy grasslands, disturbed, ruderal, and anthropogenic habitats. Being a relatively large-sized species with successful breeding strategy, it is obviously a serious competitor for other millipedes. Kryphioiulus occultus is a small species, preferring a warm climate and, at least in Hungary, seems to be confined to undisturbed, south-faced, rocky grassland associations. The characteristic sex ratio observed in both species can be considered to be usual in millipede communities; females appear in larger numbers in the pitfall traps, because there are more females, and not because they are more active (BAKER 1985). This sex ratio may be connected with the otherwise poorly known life history and breeding strategy of the species. Similarly, the increasing number of juvenile specimens of M. unilineatum during autumn may show a prospering population, while the low juvenile number in the other species may be due to its declining population. Perhaps this latter process may be explained by the expansion of the city to the Buda Mts, and the narrow tolerance limits of K. occultus. The seasonal activity diagrams (Figs 1-2) - which is the result of nocturnal feeding by millipedes (LÖSER 1980) - are typical for soil-dwelling arthropods living in warm Fig. 2. Seasonal activity pattern of Kryphioiulus occultas