Collembola
Collembola of the species P. fimata were taken
from laboratory cultures fed with bakers yeast.
Specimens were put into plastic vessels (diameter
7 cm, height 4.5 cm) containing a layer of plaster
mixed with activated charcoal (2:1) at the bottom.
The vessels were kept at 15 1C in darkness and
kept moist with distilled water. Each vessel
contained 10 individuals of P. fimata. This low
density was chosen to avoid cannibalism due to
crowding. Eggs, pellets and exuvia were removed
once a week. Collembola were fed with fungal diet
ad libitum. Round pieces of fungal mats with a
diameter of 10 mm were cut out of the agar
cultures under sterile conditions, put into the
vessels and renewed once a week. Collembola
were fed with the specific diet for 6 weeks.
Chamberlain et al. (2004) found a half life for bulk
carbon turnover rate of 3.5 days. The isotopic
composition of the Collembola in our experiments
should therefore be only due to composition of the
fungal food source.