Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/22/1996
Publication Date: N/A
Interpretive Summary: Naturally occurring protozoan parasites (Microsporidia) of insects are under study to evaluate and develop these disease causing organisms as biological control agents. Microsporidian parasites are known to cause mortality in insects worldwide, but fundamental knowledge of their life cycles and modes of transmission is presently incomplete. This investigation, using both the light and electron microscope, describes the complete life cycle of a microsporidian parasite in an orthopteran host. New information obtained here contributes to our basic understanding of these parasites which will assist in the evaluation and development of microsporidia as biocontrol agents.
Technical Abstract: A new microsporidium was isolated from the the migratory locust, Locusta migratoria, collected in Madagascar. This new species was found to be haplokaryotic throughout development, produced polysporophorous vesicles of parasite origin and there was conspicuous xenoma formation. The xenoma was a complex structure composed primarily of fat body cells. The wall of the xenoma contained many bundles of collagen-like fibrils and to a lesser degree nerve cells, trachael epithelium and muscle fibers. Multiplication of the parasite occurred by way of both a schizogonic phase as well as by a sporulation phase. Schizonts divided either directly or with the intervention of paucinucleate plasmodia into additional schizonts. At some point, plasmodia developed (with an increase in size and number of nuclei) into sporogonial plasmodia with typically 16 nuclei. Sporogonial plasmodia elaborated an interfacial envelope within which they underwent sporogony. Sporophorous vesicles normally contained 16 spores but also 8 and rarely 32 spores were formed. Spores were elongate ovoid (sometimes slightly curved) and measured 8.3 by 3.8 microns (fresh) and 6.9 4.2 microns (fixed). Based on the development of the microsporidium and the features of the xenoparasitic complex, a new species and genus Johenrea locustae n.g.,n.sp. is proposed.