Katarina Hedlund

Organic material of different origin is commonly used as fertiliser in agricultural practices. Clover and wheat straw are here used to determine the importance of organic amendment for population development of fungal feeding collembolans. Two fungal species, Alternaria infectoria and Mucor hiemalis, were inoculated in three growth substrates, clover amended soil, straw amended soil and non-amended soil, where both amendments and the soil originated from agricultural fields. Food choice as well as growth rate, survival and fecundity of the collembolan, Folsomia fimetaria, were measured when fed fungi grown in the three substrates. The type of amendment altered food quality of the two fungi, which was reflected in the collembolan food preference. Growth and fecundity of F. fimetaria were enhanced when fed M. hiemalis grown in both types of plant amended soils. F. fimetaria had a slightly higher fitness when fed A. infectoria grown in the straw amended soil, whereas it's fitness decreased when fed with A. infectoria grown in clover amended soil. We also examined how the predatory mite, Hypoaspis aculeifer, was attracted towards the two fungi as it uses the fungal odour as a potential cue of a prey habitat. H. aculeifer was attracted to both fungi when they were grown in clover amended soil where fungal growth also was observed to be massive. Thus, we conclude that amendment applications can cause effects that cascade through several trophic levels. (C) 2013 Elsevier Ltd. All rights reserved.