| Summary: | I describe several studies that investigate effects of collembolan on morphology and nutrient partitioning in mycelia of cord-forming fungi. The collembola (Folsomia candida, Protaphorura armata and Proisotoma minuta) and fungi (Phanerochaete velutina, Hypholoma fasciculare, Phallus impudicus and Resinicium bicolor) used occur commonly in British woodlands. Each study employed two-species (one fungus: one collembola) microcosms containing compressed soil. The fungus was added in a colonized wood block and allowed to grow out across the soil before collembola were added. Fungal growth and morphology were characterized using image analysis techniques. Collembolan grazing occurred predominantly on the diffuse hyphae present at mycelial margins, except for R. bicolor where thick cords were regularly severed. Grazing reduced extension rate and hyphal coverage of mycelia; effects were more dramatic at high collembolan densities. The region of mycelium attacked was consistent across collembola species; the magnitude of grazing impacts varied. Fungal responses to grazing were species-specific. R. bicolor mycelia were often destroyed, P. velutina and H. fasciculare retained an intact cord system but their growth was modified, P. impudicus was little affected. Mycelial network architecture was altered. In addition to changes in fungal morphology, wood decay rate of H. fasciculare was decreased by grazing. Mycelial nutrient distribution was explored by pulse-labelling P. velutina mycelia with 15N. This showed that P. armata grazing reduced the uptake and transfer of 15N to outgrowth mycelium, and did not increase nitrogen release into the soil.
|
|---|
