Functional Morphology of Secretion by the Large Wax Glands (Sensilla Sagittiformia) Involved in Tick Defense
Figure 2
Micrographs of sagittal sections of large wax glands (sensilla sagittiformia = arrow-organs) in nonfed adult females of R. sanguineus. (a) Intact large wax gland showing regular microscopic anatomy (corresponding drawing in Figure 1 with parts labeled that match Schulze's [2] description). The gland has a restricted pore opening (inset, direct view), a thick spongy chitinous layer, and three large glandular cells occupying most of the proximal terminal chamber lumen. Bar = 30 m, and Bar = 10 m (inset). (b) Evacuated large wax gland of ticks that had been stimulated to secrete. Most of the morphology of the large wax gland has been destroyed. Glandular cells have been forced up into the tuft chamber and distal duct, and as they existed under high pressure these cells have been broken into pieces (long arrow). The glandular cell pieces have forced open the pore and widened its diameter and the spongy elastic chitinous frame around the gland pore (inset). Note that juxtapositioned cells are hypertrophied and have started the differentiation process to replace glandular cells that had been ejected during release of the secretion (short arrow). Similar morphology was observed in 20 replicates, and these two micrographs are representative of those replicates. Bar = 30 m, and Bar = 10 m (inset).
