NICHE RELATIONSHIPS BETWEEN 2 PANPHYTOPHAGOUS SOIL MITES, NOTHRUS-SILVESTRIS NICOLET (ACARI, ORIBATIDA, NOTHRIDAE) AND PLATYNOTHRUS-PELTIFER (KOCH) (ACARI, ORIBATIDA, CAMISIIDAE)

Habitat differentiation between Nothrus silvestris and Platynothrus peltifer was studied in terms of stratification and response to environmental factors. Differences in habitat were related to differences in food preference and in the digestive possibilities of food items and the length of a starvation period. The ability of a species to digest available food items, and to endure relatively unfavourable conditions (drought), determine its habitat. This ability is particularly important when population densities are high, as in the case of juvenile life stages. The mites N. silvestris and P. peltifer, formerly considered panphytophagic, were shown to have different carbohydrase activities with regard to chitinase, trehalase, and cellulase. N. silvestris is a true panphytophage, but P. peltifer is a macrophytophage rather than a panphytophage. The evaluation of carbohydrase activity as an option in studying the field menu of microarthropods is discussed. © 1990 Springer-Verlag.