Skip to main content
SLU publication database (SLUpub)
Doctoral thesis, 2010

Unravelling the feeding habits of fungivores : interactions between soil fauna and ectomycorrhizal fungi

Remén, Cecilia

Abstract

The aim of this project was to investigate and clarify the feeding habits of fungivorous soil fauna, with the overall objective of improving our understanding of their functional roles in the ecosystem. Special focus was given to symbiotic ectomycorrhizal (EM) fungi, that, owing to their abundance and diversity, are considered to constitute an important food source for fungivorous soil fauna and may be a factor regulating these faunal communities. Previous studies on soil animal feeding habits have been strongly dependent on the methodology used; therefore an additional aim was to find the technique most suitable for studying fungivorous feeding. The results in this thesis confirm that it is necessary to combine a number of different methods in order to determine the feeding habits of fungivorous soil fauna. The total abundance of oribatid mites was significantly reduced in spruce forest stands that were girdled to restrict flow of photoassimilates to roots and ectomycorrhizal fungi, and Oppiella nova was the species that showed the most marked reduction in abundance, especially in spruce forest soils. This reduction in abundance could be explained by the results from a microcosm study, in which O. nova was clearly favoured by the presence of certain EM fungi and increased its abundance of both adults and juveniles in microcosms with the two EM species Suillus variegatus and Paxillus involutus. In the same study, Cognettia sphagnetorum was suppressed by the presence of EM fungi, which partly explains why this species reach high populations after clear-cutting. PCR in combination with washing of the body surface and dissection was a successful method for analysing diets of fungal feeding oribatid mites. This method will be considered for future analyses of field collected animals. We could also demonstrate that the isotopic composition of fungivorous animals should be interpreted with great care, when used as a method for studying fungivore feeding habits. The range of values recorded from field collected Diptera larvae utilising a single food source was large enough to span across several trophic levels when these were determined using fixed enrichment values from literature data. The δ¹⁵N of the animals was higher than that of the ingested fungal tissue, but similar to the δ¹⁵N of the protein and amino acids of the food.

Keywords

soil fauna; cryptostigmata; feeding preferences; fungi; pcr; isotopes; tracer techniques; girdling; mycorrhizae; sweden

Published in

Acta Universitatis Agriculturae Sueciae
2010, number: 2010:33
ISBN: 978-91-576-7446-3
Publisher: Dept. of Ecology, Swedish University of Agricultural Sciences

    UKÄ Subject classification

    Ecology

    Permanent link to this page (URI)

    https://res.slu.se/id/publ/29407