Cockroaches (Blatta orientalis, Blattella germanica, and/or Periplaneta americana), U.S.A. (McAdow, 1931).
Cockroach, Venezuela (Tejera, 1926).
According to Hammerschmidt (1847) this worm may be found throughout the intestinal canal but especially in the small intestine. It is frequently found in adults and seldom in the nymphs. There were seldom more than 5 to 10 worms in one cockroach and female worms were found more frequently than males; the male worms were found only in winter and spring while the females were present at all times of the year. Bütschli (1871) stated that all stages from those just hatching to mature males and females are found.
Yakimov and Miller (1922) found H. diesingi in 50.8 percent of 124 B. orientalis collected in Petrograd. Sobolev (1937) found 96 percent of B. orientalis infected with H. diesingi with a mean number of 5.6 and maximum number of 22 in one cockroach. Groschaft (1956) found 18 in one specimen of B. orientalis. Dobrovolny and Ackert (1934) found about 50 percent of 222 P. americana infected with H. diesingi. Sondak (1935) found about 36 percent of 412 B. orientalis infected with either or both H. diesingi and Leidynema appendiculata.
Two molts occur during development of the eggs; the first takes place outside the host resulting in a resting or infective stage. After the egg in the infective stage is eaten by the host, the second molt occurs before the egg hatches. Completion of the second molt and hatching perhaps are connected with ammonia present in the digestive tract; the ammonia seems to arise from the bacteria present in the gut. There appears to be a relationship between the intestinal bacteria of the cockroach and development and hatching of nematode eggs (Todd, 1944).
At the time of oviposition the nematode eggs are in the very earliest stages of cleavage. In 36 hours a motile, tadpole-like stage is reached and in a few days the embryo becomes quiescent and nonmotile. This nonmotile stage is infective whereas the motile embryonic stage is not. Feeding experiments proved that transmission of the nematode is direct. The worm reaches sexual maturity in 20 or 30 days after being ingested by the cockroach (Dobrovolny, 1933).
The bacterium Streptomyces leidynematis Hoffman grows on the cuticle of H. diesingi (Hoffman, 1953). The bacterium apparently is only anchored to the nematode and probably obtains its food from the intestinal contents of the cockroach. See notes under Leidynema appendiculata.
Hammerschmidtiella neyrai Serrano Sánchez, 1945
Synonymy.—Hammerschmidtiella neyrae Serrano Sánchez, 1947. [According to M. B. Chitwood, personal communication, 1957, Serrano Sánchez's emendation is apparently an error.]
Natural host.—Blatta orientalis, Spain, Grenada (Serrano Sánchez, 1947): Of 2,943 specimens examined, 1,143 were parasitized by oxyurids and of these 45 percent contained H. neyrai.