OCCURRENCE OF METARHIZIUM-ANISOPLIAE IN NESTS AND FEEDING SITES OF AUSTRALIAN TERMITES

A total of 479 samples of nests or feeding sites of 58 species of Aust ralian termite were plated onto a medium selective for isolation of Me tarhizium spp. Sixty-seven samples were positive for Metarhizium spp. and a total of 97 isolates of M. anisopliae were obtained. Very few is olates were obtained directly from Infected termites. Most isolates we re obtained from nest-mound material from eastern Australia. Termite-a ssociated material from the two common mound-building species of termi te, Nasutitermes exitiosus and Coptotermes lacteus, provided 75 of the isolates, Similar material from 26 species of termites revealed no Me tarhizium. A detailed study of two sites found that some of the Metarh izium isolates found in nest-mound material, including also some M. fl avoviride and M. album, were of morphological types also present in ad jacent soil. The DNA of isolates from mounds and the adjacent soil wer e compared using RAPDs and sequence analysis of the ITS region of the nuclear rDNA and the same types were found from both sources. The poss ible role of the fungus in termite ecology is discussed and it is thou ght most likely that Metarhizium is only opportunistically a pathogen of termites, Thus, isolates obtained from termite nest material are pr obably there because of the incorporation of soil into termite nests.