Biosynthesis and accumulation of formic acid in the poison gland of the carpenter ant Camponotus pennsylvanicus

Formic acid synthesis in the poison gland of Camponotus pennsylvanicus is closely related to the C-1 metabolism of the glandular cells. Serine, glycine, and histidine are potential C-1 donors to formic acid by several tetrahydrofolate intermediates. Formic acid is accumulated by its transfer to an insulated reservoir, so that the ant avoids the acid's cytotoxicity. This combination of biochemical and morphological features provides an autodefensive mechanism. Possible factors that regulate the biosynthesis of formic acid in the poison gland apparatus are discussed.