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.