Host Specificity of Five Species of Eugregarinida Among Six Species of Cockroaches (Insecta: Blattodea)

Abstract

Eugregarines are typically distinguished using characters, such as epimerite morphology, trophozoite morphometrics, timing of reproductive association, gametocyst morphology, and method of dehiscence. In some cases, new gregarine species have been recognized based solely on host associations, whereas other gregarine species have been reported from several host taxa. We used reciprocal cross-species experimental infections and in vitro excystation assays to evaluate the host specificity of 5 species of eugregarines among 6 species of cockroaches: Protomagalhaensia granulosae Peregrine, 1970, and Gregarina cubensis Peregrine, 1970, described from Blaberus discoidalis, (death's head cockroach); Leidyana migrator Clopton, 1995, described from Gromphadorhina portentosa (Madagascar hissing cockroach); and Protomagalhaensia wolfi (Geus, 1969) Hays and Clopton, 2006, and Leidyana haasi (Gues, 1969) Hays and Clopton, 2006 infecting Nauphoeta cinerea (lobster cockroach). Eugregarines have not been reported from the other species of cockroaches used in this study: Blaberus giganteus (giant death's head cockroach), Henschoutedenia flexivitta (giant lobster cockroach), and Diploptera punctata (Pacific beetle mimic). Experimental infections were produced in all homologous host–parasite combinations. With the exception of 1 host–gregarine combination, no infection was produced in heterologous reciprocal combinations. Excystation occurred in all instances when oocysts were placed in homologous host gut homogenate but excystation was never observed in heterologous host gut homogenate.