The abundance of oribatids in natural biotopes in the temperate region is characterised by two peaks, in spring and in autumn. We tested, whether these abundance peaks are accompanied by high feeding activity of Galumna elimata population. The defecation was used as an indirect estimation of the feeding activity. The model of seasonal changes of population defecation activity was constructed. Temperature dependence of defecation measured previously in laboratory and Galumna abundance data front 4 meadow plots in Central Bohemia were used for the model. The mites were sampled monthly from 1992 to 1993. The monthly defecation per Galumna population on each plot was adjusted to mean monthly temperatures and to mean monthly abundance. The estimated maximal population faecal pellets production was not correlated to the abundance peaks on three from four plots. The model showed that mites defecated particularly from May to September. In the autumn, when abundance was high, negligible defecation was found. The model of seasonal changes indicates that oribatid defecation may influence activity of microorganisms mainly in late spring and in summer.