Pimeliaphilus podapolipophagus Trägårdh
Common name.—Cockroach mite.
Natural hosts.—Parcoblatta sp., U.S.A. (Edmunds, 1953a).
Periplaneta americana, U.S.A. (Piquett and Fales, 1952).
Cockroaches. U.S.A. (Baker and Wharton, 1952).
Experimental hosts.—Blatta orientalis, Blattella germanica, and Periplaneta americana, U.S.A. (Cunliffe, 1952).
Eggs of this mite (fig. 4) are usually laid indiscriminately in the rearing cages, rarely on the host. Eggs are coated with a sticky secretion which enables those laid on the host to adhere. Hatching occurs in 6-11 days at 90-95° F., and in 9-11 days at 80° F. The newly hatched larva starts to feed immediately on the cockroach. Larval stage lasts 4-6 days, rests 2-3 days, and molts. During the single nymphal instar, the mite feeds on the host and moves about for 6-7 days. The mite then rests 3-4 days before molting. Entire life cycle covers a period of 28-32 days. Adult mite lives 2-3 weeks, during which time it can produce 2-3 batches of from 1 to 20 eggs; the usual batch is about 12 eggs. The mites are unable to live on cockroach feces, cast skins, or dead cockroaches. Mites died within 4-5 days unless live cockroaches were supplied. Parasitism was proved by detecting radioactivity in mites that had fed on cockroaches which had been previously fed radioactive NaCl (Cunliffe, 1952).
The mites can destroy laboratory cultures of cockroaches (Piquett and Fales, 1952; Edmunds, 1953a). A cockroach attacked by 25 mites succumbed after about an hour, falling on its back; it died after 5 hours (Cunliffe, 1952).
When found in homes and offices, these mites are an indication of the presence of cockroaches; the mite has been twice accused of biting people (Baker et al., 1956).