Entomopathogenic nematodes occurring in forest habitats and their role in a forest ecosystem

点击翻译按钮获取中文摘要

Surveys were done in forests located in Tokyo, Hakone and Tesikaga to determine the occurrence of entomopathogenic nematodes and to elucidate the role of these nematodes along a trophic chain within a forest ecosystem. Soil samples from forest habitats were tested for the presence of nematodes by baiting with Galleria mellonella larvae. An undescribed Steinernema species occurred at all sites surveyed. The nematode is closely related to S.feltiae, but it can be differentiated from S.feltiae by some morphological and biological characteristics. It was indicated that this nematode might be widely distributed and of common occurrence in forest habitats of eastern Japan. Based on the life cycle observed on nematode infected Galleria larvae, it could be concluded that this nematode was cold active. The horizontal spatial pattern of the nematode in its natural habitat was patchy or aggregated. The available data suggested that this nematode was a cruiser nematode as to its host finding behavior. In the larch forest of Tamagawa University Forest in Teshikaga where an outbreak of larch sawfly, Cephalcia sp.occurred sawfly larvae in soil were naturally infected with the nematode. This is the first known record of this genus in a sawfly in Japan.