AUTOMATIC COUNTING OF COLLEMBOLANS FOR LABORATORY EXPERIMENTS

A new procedure involving digital image processing and image analysis for determination of the number of individuals and size distribution o f a collembolan population is presented. It is applicable to experimen ts conducted with a single species either on plaster or in soil. Colle mbolans are transferred to an even, black surface and immobilised by a naesthetisation with carbon dioxide. By scanning the surface with the collembolans, the number and size of individuals are quantified. In su bsequent data treatment steps, adults and clutches of juveniles can be discriminated using an ordination or clustering technique. The method is illustrated by the weekly population development of Folsomia candi da Willem in the laboratory. (C) 1998 Elsevier Science B.V.