The madagascar hissing-cockroach mite (Gromphadorholaelaps schaeferi): First observation of its larva and ptyalophagy in Acari

Postembryonic development in the Madagascar hissing-cockroach mite, Gromphadorholaelaps schaeferi, features a mobile, but non-feeding larva of very short duration (4-8 hours). Until now, this mite was thought to be protonymphiparous, which is not consistent with other members of this taxon. In this study, four distinct stages were found: larva, protonymph, deutonymph, and adult. The larva exists for mobility and escape from maternal cannibalism, and then quickly moults to the protonymph to feed and grow. Extra features are arrhenotoky, autogeny, and ability to moult successfully without feeding. These mites feed on cockroach saliva expressed during feeding, grooming and in defense. This ptyalophagy (Gr. ptyalon spittle) is unique among Acari. Thus, the heretofore unknown link between the hissing-cockroach mites and the cockroach is saliva, and this is the first reported role of the cockroach in mite feeding. Host location by these olfactorous mites was confirmed using water extracts of cockroaches to which mites responded in a quantitative manner for host instar sorting. In accommodating its life to one of the most remarkable and unusual blattids, the life history traits of this mite mirror features of the cockroach life history.