Assessing the Efficiency of Molecular Markers for the Species Identification of Gregarines Isolated from the Mealworm and Super Worm Midgut

Morphological evidence of gregarines (Phylum: Apicomplexa) in Triatoma dimidiata, Chagas disease vector in Mexico: Rediscovering Machadoella triatomae and a new intestinal gregarine

The objective of this study was to morphologically characterize the structures suggestive of gregarines found in the feces of Triatoma dimidiata collected in five municipalities in Yucatan, Mexico. Three hundred ninety-six specimens of T. dimidiata collected during 2022 and 2023 were analyzed, of which 8.84 % (n = 35) showed evidence of infection by a gregarine in the intestine and 1.77 % (n = 7) of infection with vermiform gregarine in Malpighian tubules. With microscopic examination, it was possible to obtain measurements and micrographs that allowed the rediscovery of Machadoella triatomae (vermiform gregarine) as well as a potential new gregarine species not previously described in T. dimidiata, which, based on its morphological characteristics, could be another Schizogregarina of the genus Caulleryella (flask-shaped). Additionally, the dissections of some specimens helped correctly identify the site where these gregarines parasitized T. dimidiata. Furthermore, of the three staining techniques used in this study, Lugol's solution and Wright's stain provided greater contrast and were therefore useful for visualizing these microorganisms. Scanning electron microscopy of the new gregarine revealed the three-dimensional shape of merozoites inside and outside a ruptured meront in detail. This study provides morphological evidence of two gregarines (Phylum: Apicomplexa) parasitizing Triatoma dimidiata in multiple regions of Yucatan, Mexico. M. triatomae was isolated in Malpighian tubules, and another gregarine, possibly of the genus Caulleryella, was isolated in the intestine.

Integrative taxonomy confirms that Gregarina garnhami and G. acridiorum (Apicomplexa, Gregarinidae), parasites of Schistocerca gregaria and Locusta migratoria (Insecta, Orthoptera), are distinct species

Orthoptera are infected by about 60 species of gregarines assigned to the genus Gregarina Dufour, 1828. Among these species, Gregarina garnhami Canning, 1956 from Schistocerca gregaria (Forsskål, 1775) was considered by Lipa et al. in 1996 to be synonymous with Gregarina acridiorum (Léger 1893), a parasite of several orthopteran species including Locusta migratoria (Linné, 1758). Here, a morphological study and molecular analyses of the SSU rDNA marker demonstrate that specimens of S. gregaria and specimens of L. migratoria are infected by two distinct Gregarina species, G. garnhami and G. acridiorum, respectively. Validation of the species confirms that molecular analyses provide useful taxonomical information. Phenotypic plasticity was clearly observed in the case of G. garnhami: the morphology of its trophozoites, gamonts and syzygies varied according to the geographical location of S. gregaria and the subspecies infected.

First record of gregarine protists (Apicomplexa: Sporozoa) in Asian fungus-growing termite Macrotermes barneyi (Blattaria: Termitidae)

Macrotermes barneyi, widely distributed in southern China, is the major fungus-growing termite in the subfamily Macrotermitinae. It has no flagellated protists in the guts. Here, we report occurrence of gregarine, a protozoan parasite in the digestive tract of M. barneyi. The general morphology and ultrastructure of the gregarine gamonts and syzygies by light micrograph and scanning electron micrograph are presented. SSU rDNA sequence analysis showed that the termite gregarine has the highest identity (90.10%) to that of Gregarina blattarum from cockroaches. Phylogenetic analysis based on the SSU rDNA sequences from diverse insect eugregarines indicated that the gregarine from M. barneyi is phylogenetically close to G. blattarus, L. erratica and G. tropica from Gregarinidae and Leidyanidae families, and may represent a novel species. This study expands our knowledge about the diversity of terrestrial eugregarines parasitizing in termites.