2.2.1. Mite appearance

Adult female tracheal mites have a pyriform (pear-shaped) body (Fig. 2), measuring 120 to190 µm long by 77 to 80 µm wide. Female mites can be distinguished by their stubby form and the presence of five setae on leg IV (Fig. 1C). Adult males are 125 to 136 µm long by 60 to 77 µm wide (Fig. 2). Leg IV of the males lacks all the tarsal structures. Both sexes have the dorsum covered with round to elongated bumps and an absence of bothridial setae on the prodorsal area (Fig. 2). The gnathosoma contains the mouth parts, palps and the chelicerae. Ventrally, the adults have an anterior apodeme forming a Y-shaped juncture with the prosternal apodeme (Fig. 1C). All tracheal mites are a semi glossy white colour.  Immature mites have 3 pairs of legs and are bigger than the adult female (Figs 3 and 6C).  Delfinado-Baker and Baker (1982), Lindquist (1986) and Ochoa et al. (2005) present detailed descriptions of the genus Acarapis, and in particular of A. woodi.

Fig. 2.  LT-SEM micrographs of the dorsal view of a male (top) and female (bottom) of A. woodi. (Photos: E Erbe and R Ochoa).


Fig. 3. SEM micrographs of anterior region of A. woodi female (left) and close-up of the larva (right). Photos: E Erbe and R Ochoa.