Feeding preferences of the collembolan Folsomia candida in relation to microfungal successions on decaying litter

The feeding preferences of two strains of the collembolan, Folsomia Candida, for some common primary and secondary saprophytes of spruce and fir litter were investigated. The fungi were grown on spruce or fir litter, or on cellophane strips that had been placed on top of malt agar. The ability of the animals to survive and reproduce on the fungi was also investigated and a microcosm system was used to examine the effect of collembolan grazing on the microfungal succession on spruce litter. The experiments demonstrated selective feeding. Generally the insects preferred primary saprophytes to secondary saprophytes and selected foods that increased their fecundity. The microcosm study showed that the absence of the grazers slowed down the rate at which primary saprophytes on litter were replaced by secondary saprophytes. These data therefore support the hypothesis that fungal successions observed in the field on decaying litter may result from preferential grazing by microarthropods.