Experimental infection of the hemipteron Oncopeltus fasciatus with trypanosomatidae isolated from other hosts.

Abstract

SYNOPSIS. In an effort to determine the degree of host specificity and morphology of the insect trypanosomatids in a presumably foreign host, individuals of a laboratory colony of the hemipteron Oncopeltus fasciatus were given intra‐rectal injections with various species of axenically cultured parasites. Crithidia isolated from the hemipterons Acanthocephala femorata, Euryophthalmus davisi, and Arilus cristatus, as well as those from the dipterons Phaenicia sericata and Culex pipiens, and Crithidia (Strigomonas) oncopelti presumably isolated from O. fasciatus or Asclepias syriaca, demonstrated extensive multiplication whereas a leptomonad from the hemipteron Leptoglossus phyllopus and a blastocrithidian from the hemipteron Euschistus servus underwent little reproduction and disappeared after 8 and 25 days respectively. Another blastocrithidian taken from the hemipteron Melanolestes picipos flourished and has been transferred through 7 generations of O. fasciatus. None of the crithidia were transmitted although numerous flagellates and leishmaniform bodies were observed in the feces of bugs injected with all species.The crithidia in the gut of O. fasciatus were somewhat more elongated than culture forms and this appeared to be particularly marked in the dipteron group. In bugs injected with C. acanthocephali and C. oncopelti a few specimens were seen with the kinetoplast posterior to the nucleus. Leptomonas leptoglossi enlarged markedly when injected into the gut of O. fasciatus and in many organisms the nucleus was displaced to the posterior half of the body. There was no apparent change in the morphology of the two blastocrithidia in this host.Although some minor morphological changes were observed, this work in general supports the view of Wallace that Crithidia is a distinct genus and probably does not represent a stage in the life cycle of other organisms.