Characteristics of Tylencholaimus parvus (Nematoda: Dorylaimida) as a fungivorus nematode

Abstract

AbstractTo analyse nematode community structures appropriately for the evaluation of soil ecosystem status and function requires information on the life history traits of K-strategic nematodes. Therefore, a K-strategic fungivorus nematode, Tylencholaimus parvus, was examined for population growth rates on nine fungal species on agar and on soil-based media. Also, the nematode was compared with an r-strategic fungivorus nematode, Aphelenchus avenae, in terms of population growth rates on potato dextrose agar (PDA), and of prey-predator relationships with nematophagus fungi, Pleurotus spp., growing on water agar. Population growth rates of T. parvus on PDA were large on three plant-pathogenic fungi, Botrytis cinerea, Fusarium oxysporum and Phoma herbarum. On the soilbased medium, two saprophytic fungi, Coprinus cinereus and Flammulina velutipes, also supported large population increases of the nematode, as well as F. oxysporum and P. herbarum. Tylencholaimus parvus always had significantly smaller growth rates than A. avenae, and the rates of T. parvus were 0-24% of those of A. avenae on a given fungal species. Tylencholaimus parvus was able to avoid predation of the two Pleurotus species and fed upon the fungal hyphae to reproduce, although A. avenae was killed and consumed by the fungi.