The feeding preference of a collembolan (Folsomia candida Willem) on ectomycorrhiza (Pisolithus tinctorius (Pers.)) varies with mycelial growth condition and vitality

The feeding preference of Folsomia candida Willem (Collembola), for mycelia of ectomycorrhiza (Pisolithus tinctorius (Pers.)) was investigated, in order to predict the effects of Collembola on plant-mycorrhizal systems. We compared the impacts of different mycelial growth substrates, such as MMN agar medium and root of red pine (Pinus densiflora Sieb. et Zucc.), and of mycelial vitality on the feeding preference of the Collembola. Mycelial vitality was controlled by cutting the mycelium off the host root and assuming vitality would decrease after cutting. The insect preferred mycelia grown on the MMN agar to the mycorrhizal mycelia. Although mycelia grown on nutrient medium have been used in numerous preference tests, our results demonstrate that mycorrhizal mycelia should be used for understanding the relationships between Collembola and ectomycorrhiza in preference tests. On the other hand, another experiment showed that the insect chose mycorrhiza cut from the root 56 h prior to the feeding test more often than freshly cut ones, that is, low vitality mycelia more than high vitality ones. Therefore we predict that Collembola have positive effects on plant growth by enhancing nutrient release from low vitality and/or dead mycorrhizal mycelia. [Copyright &y& Elsevier]