Morphological and genetic characteristics of the entomopathogenic fungus Ophiocordyceps nutans and its host insects.

We examined the morphology, genetic variation, and insect host species of the fungus Ophiocordyceps nutans. Fifty-two fruit bodies collected in Hokkaido, Japan, were grouped by host species, and 19 samples were analysed. The ranges of the lengths and breadths of all fruit body parts were similar among host groups. In the genetic analysis, the 5.8S rDNA region showed completely identical sequences, although differences of up to six nucleotides were recognized in the ITS regions. The distance values between our samples using the Kimura two-parameter model were lower than 0.007. Thus, the O. nutans examined here were concluded to form a closely related group with little detectable variability that parasitized nine hemipteran species.