DEFENSIVE PRODUCTION OF FORMIC-ACID (80-PERCENT) BY A CARABID BEETLE (GALERITA-LECONTEI)

The carabid beetle Galerita leeontei his a pair of abdominal defensive glands that secrete a mixture of formic acid, acetic acid, and lypoph ilic components (long-chain hydrocarbons and esters). Formic acid, at the concentration of 80%, is the principal constituent, The beetle eje cts the secretion as a spray, which it aims accurately toward parts of the body subjected to assault, At full capacity, the glands store 4.5 mg of formic acid (3% of body mass), enough for upward of six ejectio ns, The beetle reloads the glands at a rate of 126 mu g of formic acid per day. For the approximately 500 secretory cells of the glands, thi s means an hourly output of 10 ng of formic acid per cell, or about 5% of cell volume, Replenishing empty glands to their full formic acid l oad takes the beetle an estimated 37 days. Replenishing the 0.7 mg of formic acid expended in a single discharge takes 5.5 days.