The biota associated with Monochamus species collected in Maine include species of Acarina, Diptera, Hymenoptera and Nematoda, as well as fungal and bacterial pathogens.
Mites belonging to seven families and thirteen genera were found in association with the sawyers. Two species were previously unknown and have since been described as the new genus and species Longoseius cuniculus Chant of the family Digamasellidae and the new genus and species Mucroseius monochami Lindquist of the family Blattisocidae. Parasitic diptera belonged to three genera in three different families, and of these one contained a new species, Forcipomyia innom., family Ceratopogonidae, which was found as an intermittent parasite of adult Monochamus notatus and Monochamus scutellatus. This constitutes a new host record for the biting midge family. Only one hymenopterous parasite, a species of Dolichomitus was reared from a sawyer larva. The five genera of nematodes isolated from larvae, pupae, and adults of Monochamus species include specimens of the genus Hexamermis. Parasitism by this group is thought to be unusual because of the relative inaccessibility of the host. Isolates from eight fungal genera were obtained, and strains of Beauveria bassiana, and Isaria farinosa, were shown to be pathogenic. The bacteria isolated from dead sawyers included Aerobacter aerogenes, Bacillus cereus var. mycoides, and one unidentified species. Only the tachinid E. monohammi and the mite Uropoda have been previously reported of the large number of organisms found associated with sawyer beetles in this study. The fungus Beauveria bassiana proved to be the most important biological control agent.