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Vitamin B 12 concentrations were determined by radioassay in the housefly, five species of termites, and 17 other phylogenetically diverse insect species. Vitamin B 12 was not detected in the housefly Musca domestica , which apparently cannot interconvert propionate and succinate. In contrast, the termite Zootermopsis angusticollis readily interconverts succinate and methylmalonate, and contains high amounts of vitamin B 12 (940 pg/mg dry tissue), as do four other species of termites. Experiments involving selective elimination of either gut tract protozoa or bacteria in Coptotermes formosanus indicate that intestinal bacteria are the major source of vitamin B 12 in this termite. The other insect species examined have undetectable to moderate amounts of vitamin B 12 . |
