Fungal species selection during ectomycorrhizal grazing by Collembola

Collembola are one of the most abundant groups of arthropods, with fungi being an important part of their diet. Collembolan grazing of ectomycorrhizae (ECM) can sever connections between the host root and hyphal networks, interrupting nutrient flow and negatively impacting plant growth. Much of the previous information on interactions between Collembola and ECM has been based on mycelium grown in pure culture, which has artificially high nutrient levels and may lack physical and chemical grazing deterrents seen when ECM form on plant roots. We investigated Collembola feeding preferences by offering naturally occurring ECM, identified by ITS sequencing, to Folsomia candida and Protaphorura armata. We also assessed the gut content fungi of Folsomia collected in a mature Pinus strobus stand. We found that some ECM types, including the Tricholoma aestuans, Piloderma bicolor and the tuburculate ECM of Suillus spraguei, were readily grazed, while Cenococcum geophilum and Lactarius vinaceorufescens were unpalatable. Fungi forming unpalatable ECM were readily grazed when not in symbiosis with the host root.