Methods for rearing scutacarid mites (Acari, Heterostigmatina) and the influence of laboratory cultures on morphometric variables.

Mites of the soil inhabiting family Scutacaridae (Heterostigmatina) are distributed throughout the world, but only rarely found in high densities. Larvae and males are extremely difficult to detect and identify in soil samples. Laboratory cultures are necessary to describe these life stages, detect female dimorphism, or carry out other kinds of biological study. The present paper gives an historical overview of the methods applied for rearing scutacarids, demonstrating that thus far the use of glass tubes stuffed with soil is the most valuable method. Morphometric comparisons between field collected and laboratory reared specimens of two scutacarid species, Scutacarus acarorum Goeze and Heterodispus foveatus Jagersbacher-Baumann and Ebermann, revealed a clear influence of environmental conditions on the phenotype of laboratory-reared mites. Size correction minimized the environmentally induced variation and should therefore be mandatory for classification of species based on morphometric variables. Taxonomic assignment of laboratory reared scutacarids is possible, but must be done with extreme caution.