SEASONAL ABUNDANCE OF MILLIPEDES IN A MEDITERRANEAN OAK FOREST (SOUTHERN FRANCE)

The millipede community of a helm oak forest (Quercus ilex) in souther n France was sampled seasonally for 2 yr, at two depths in the forest floor. Despite the strong seasonality of climatic conditions, both rec ruitment periods and vertical displacements in the soil change markedl y according to species; contrasting examples are provided by Glomeris marginata, which breeds in summer and burrows in winter, and by Opisth ocheiron elegans, which behaves the opposite way. At the community lev el, biomass changes significantly between a spring minimum and an autu mn maximum. Such a pattern results from the high abundance of G. margi nata, a drought-resisting species which grows and reproduces during su mmer but experiences substantial winter mortality. The seasonal patter n is different in number of individuals due to the minute litter-dwell er Polyxenus lagurus, which has a low population density in early autu mn. The biomass of macrosaprophagous millipedes on the site (annual me an of 10.5 g live weight m(-2); autumn peak of 14.6 g live weight m(-2 )) is much higher than that recorded further north in Europe, and its significance for litter consumption in Mediterranean forest is discuss ed.