SECRETION OF SQUALENE BY TICKS

The nature of the fluid secreted from the dorsolateral surface of cert ain ticks was analyzed chemically and by correlating secretory activit y with the presence of glands. A waxy fluid flows from particular line arly arranged pores (''sagittiform sensilla'') that characterize metas triate ticks when their legs are pressure-stimulated. The secretion is released from a reservoir located beneath the cusp-like valves of the inner chamber of the gland and comprises almost 2% of the tick's body weight. It is replenished within 10 days, regardless of the water rel ationships of the tick. Gas chromatographic and mass spectral analysis demonstrate that its dominant component (at least 25% of non-volatile mass) is squalene. This pressure-stimulated, squalene-containing secr etion of the ''large wax glands'' of metastriate ticks has the charact eristics of a defense secretion.