Gregarine Species Research Articles

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.

Influence of medicinal plants on Blaberus craniifer cockroaches and their parasites, gregarines and nematodes

Cockroaches, especially those living in forest litter and feeding on foliage, have been consuming plants for millions of years. Can secondary metabolites of plants affect the parasite-host system and successfully treat the cockroaches’ parasites gregarines and nematodes? In our experiment, 204 Blaberus craniifer (Blattodea, Blaberidae) cockroaches consumed the standard diet supplemented with medicinal plants in a dose of 10% of the general fodder mass, particularly, plants of the families Acoraceae (Acorus calamus), Papaveraceae (Chelidonium majus), Rosaceae (Potentilla erecta), Juglandaceae (Juglans regia), Fagaceae (Quercus robur), Brassicaceae (Capsella bursa-pastoris), Hypericaceae (Hypericum perforatum), Gentianaceae (Centaurium erythraea), Lamiaceae (Origanum vulgare, Salvia officinalis, Thymus pallasianus), and Asteraceae (Achillea millefolium, Arctium lappa, Artemisia absinthium, Matricaria chamomilla, and Tanacetum vulgare). With age (i.e. gaining body mass), the intensity of infestation of cockroaches with female and male nematodes Cranifera cranifera significantly increased. The multifactor dispersion analysis found no significant effect of the number of parasites (two gregarines, Blabericola cubensis and Protomagalhaensia granulosae, and one nematode, Cranifera cranifera) on the rates of changes in body mass of the cockroaches during the experiment. Also, there was observed no effect of the number of parasites on the rates of cockroaches’ food consumption. The rates of body-mass gain during the experiment were closely associated with the initial body mass of the cockroaches: the larger the cockroach was in the beginning of the experiment, the greater the increase in its body mass later in the experiment. None of the three species of B. craniifer parasites that we studied significantly changed their numbers when subject to 10% dry medicinal plants in the hosts’ fodder, compared to the control group of cockroaches that did not consume the medicinal raw material. Intake of none of the 16 species of medicinal plants we tested led to significant changes in the rates of body-mass gain in the cockroaches. Compared to the control group, the experimental groups of cockroaches had no significant changes in the fodder consumption rates. Our experiment demonstrated that the cockroaches, together with their parasites, are substantially adapted to the influences of secondary metabolites of the 16 medicinal plants that we studied, although, in their natural range they had most likely never encountered any of those plants. Therefore, on the one hand, the considered parasite-host system was observed to be very balanced, the host being minimally harmed, and on the other hand, secondary metabolites of the plants had no significant effect either on the parasites (two species of gregarines and one species of nematodes) or on their hosts even in the highest tested concentrations (10% of the fodder mass).

Molecular phylogeny of the Lecudinoidea (Apicomplexa): A major group of marine gregarines with diverse shapes, movements and hosts.

Gregarine apicomplexans are ubiquitous endosymbionts of invertebrate hosts. Despite their ecological and evolutionary importance, inferences about the phylogenetic relationships of major gregarine groups, such as the Lecudinidae and Urosporidae, have been hindered by vague taxonomic definitions and limited molecular and morphological data. In this study, we investigated five gregarine species collected from four families of polychaete hosts (Nereididae, Oenonidae, Hesionidae, and Phyllodocidae) using light microscopy (LM) and scanning electron microscopy (SEM). We also generated small subunit ribosomal DNA sequences from these species and conducted molecular phylogenetic analyses to elucidate the evolutionary relationships within the Lecudinoidea. Our results include new molecular and morphological data for two previously described species (Lecudina cf. platynereidis and Lecudina cf. arabellae), the discovery of a new species of Lecudina (L. oxydromus n. sp.), and the discovery of two novel species, namely Amplectina cordis n. gen. et. n. sp. and Sphinctocystis inclina n. sp. These two species exhibited unique shapes and movements, resembling those of urosporids but with a phylogenetic affinity to lecudinids, blurring the border between lecudinids and urosporids. Our study emphasizes the need for further investigations into this highly diverse group, which has achieved great success across multiple animal phyla with diverse shapes and movements.

Gregarines of mass species of darkling beetles (Coleoptera, Tenebrionidae) of Ukraine

Gregarines (Apicomplexa: Eugregarinida) are protists that live in the digestive tract and other body cavities of numerous terrestrial and aquatic invertebrates. The gregarine fauna of Eastern Europe has not yet been sufficiently studied. In the course of this study, we aimed to record gregarines living in the insides of the most widespread species of darkling beetles (Tenebrionidae: Coleoptera) in steppe zone of Ukraine. We found 7 species of gregarines belonging to 3 families: Actinocephalidae, Gregarinidae and Stylocephalidae, with the latter family being the most diverse. Gregarina Steinina diaperis was recorded in Diaperis boleti, Gregarina ormierei in Gonocephalum pusillum, and G. ovoidea in Asida lutosa. As for members of the family Stylocephalidae, Sphaerorhynchus cf. hamoni was found in G. pusillum, Stylocephalus gigas in Blaps lethifera, S. longicollis in Gnaptor spinimanus, and S. oblongatus in A. lutosa, Opatrum sabulosum, Oodescelis melas, and Pimelia subglobosa. G. ovoidea Wellmer, 1911, S. gigas Filipponi, 1949, S. longicollis (Stein, 1848) Watson, 1916 and S. oblongatus (Hammerschmidt, 1838) Watson, 1916 were first found in a new host species. All the identified species are new to the fauna of Ukraine and are recorded for the first time in the steppe zone of Eastern Europe.

Gregarines impact consumption and development but not glucosinolate metabolism in the mustard leaf beetle.

Gregarines are usually classified as parasites, but recent studies suggest that they should be viewed on a parasitism-mutualism spectrum and may even be seen as part of the gut microbiota of host insects. As such, they may also impact the consumption of their hosts and/or be involved in the digestion or detoxification of the host's diet. To study such effects of a gregarine species on those traits in its host, the mustard leaf beetle (Phaedon cochleariae) was used. This beetle species feeds on Brassicaceae plants that contain glucosinolates, which form toxic compounds when hydrolyzed by myrosinases. We cleaned host eggs from gametocysts and spores and reinfected half of the larvae with gregarines, to obtain gregarine-free (G-) and gregarine-infected (G+) larvae. Growth and food consumption parameters of these larvae were assessed by rearing individuals on watercress (Nasturtium officinale, Brassicaceae). A potential involvement of gregarines in the glucosinolate metabolism of P. cochleariae larvae was investigated by offering G- and G+ larvae leaf discs of watercress (containing mainly the benzenic 2-phenylethyl glucosinolate and myrosinases) or pea (Pisum sativum, Fabaceae, lacking glucosinolates and myrosinases) treated with the aliphatic 4-pentenyl glucosinolate or the indole 1-methoxy-3-indolylmethyl glucosinolate. Larval and fecal samples were analyzed via UHPLC-QTOF-MS/MS to search for breakdown metabolites. Larval development, body mass, growth rate and efficiency to convert food into body mass were negatively affected by gregarine infection while the pupal mass remained unaffected. The breakdown metabolites of benzenic and aliphatic glucosinolates were conjugated with aspartic acid, while those of the indole glucosinolate were conjugated with glutamic acid. Gregarine infection did not alter the larvae's ability to metabolize glucosinolates and was independent of plant myrosinases. In summary, some negative effects of gregarines on host performance could be shown, indicating parasitism. Future studies may further disentangle this gregarine-host relationship and investigate the microbiome potentially involved in the glucosinolate metabolism.

Description and prevalence of gregarines infecting the amphipod Gammarus pulex, in the Water of Leith, Scotland, UK

Gregarines are symbiotic protists that are found in a broad spectrum of invertebrates, including insects, crustaceans, and annelids. Among these the globally distributed amphipod Gammarus pulex is one of the earliest recognized hosts for aquatic gregarines and is prevalent among macroinvertebrates in freshwater environments. In this study, samples of G. pulex were collected in the Water of Leith river, Scotland, UK. Gregarines were identified using light and scanning electron microscopy as well as standard molecular techniques. We identified three septate eugregarine symbionts—Heliospora longissima, Cephaloidophora gammari, and the here newly characterized Cephaloidophora conus n. sp. (formerly Cephaloidophora sp.) associated with Gammarus pulex in the Water of Leith. Prevalences for identified gregarine species were calculated and seasonal dynamics of gregarine infections/colonization were analyzed. Prevalences were highest in autumn and spring reaching almost 50 %. While the two Cephaloidophora species showed similar colonization patterns, the prevalence of Heliospora showed an opposite trend. Identifying gregarine infection/colonization patterns is one step towards better understanding the gregarine–host relationship, as well as possible impacts of the gregarines on their hosts.

GREGARINA LUTESCENS N. SP. INFECTING THE HARLEQUIN LADYBIRD HARMONIA AXYRIDIS (COLEOPTERA: COCCINELLIDAE).

Gregarina lutescens n. sp. is described from the alimentary canal of the harlequin ladybird or multicolored Asian lady beetle, Harmonia axyridis (Coleoptera: Coccinellidae) collected from prairie fleabane, Erigeron strigosus, at Peru State College, Peru, Nemaha Co., Nebraska. Our specimens differ from all 11 known species of Gregarina infecting coccinellid beetles worldwide by differences in size and relative shape, color, and association structure. Gregarina lutescens n. sp. is smaller than 7 known species infecting coccinellid beetles but larger than the other 4 known species based on confidence interval exclusion of means. Our specimens are unique among known species of interest in their quince-yellow cytoplasm and precocious but ephemeral serial associations of up to 5 satellites. Nucleotide sequence (18S) phylogenetic analyses place the new species basal to a member of an internal clade of Gregarina that comprises gregarines parasitizing chrysomelid beetles. Phylogenetically, the analysis recovered 3 major lineages within the gregarines, representing the superfamilies Gregarinoidea, Stenophoroidea, and Stylocephaloidea and indicating the propensity of gregarines to track host lineages and environments through evolutionary time. These findings confirm the polyphyletic nature of Gregarina, which currently comprises over 300 described species, only a handful of which have documented genetic sequences suitable for phylogenetic analysis. Recollection, redescription, and molecular clarification of gregarine species infecting coccinellids would likely result in identification of a unique clade that would be an excellent system for studying the effect of intraguild host competition on parasite diversification and community structure. Ecologically, patterns of prevalence in this study indicate that G. lutescens reproduces primarily in larval hosts but depends on infections in adult beetles to overwinter, reflecting the differential vagility and frost tolerance of larval and adult host life cycle stages.

Body-weight gains in Blaberus craniifer cockroaches and the intensity of their infection with gregarines and nematodes

Intestinal parasites are considered to be able to hinder growth of the host animals, reducing the extent of food metabolism, damaging the intestines’ integrity by filling it with products of their metabolism. However, a long co-evolution can mitigate the negative impact of a parasite on the host organism. To study how parasites – nematodes Cranifera cranifera (Chitwood, 1932) Kloss, 1960 (Oxyurida, Thelastomatidae) and gregarines Protomagalhaensia granulosae Peregrine, 1970 and Blabericola cubensis (Peregrine, 1970) Clopton, 2009 (Eugregarinorida, Blabericolidae) – afffect the growth rates of cockroaches, we performed an experiment on 200 larvae of Blaberus craniifer Burmeister, 1838 (Blattodea, Blaberidae), varying in weight and age. We monitored changes in their body weight, intensity of food consumption, and after the experiment we counted gregarines in the midgut and nematodes in the hindgut. As a result, we found that 100% of the cockroaches were infected with two species of gregarines and one species of nematodes. The intestines of small cockroach larvae (weighing 300–400 mg) contained 16–18 specimens of gregarines on average. Large larvae had a weak tendency towards increase in the intensity of gregarine infestation. Similarly, there occurred changes in the intensity of nematode invasion: young larvae were infected on average by 8–10 specimens of nematodes and large larvae had an average of 12–14 nematodes. At the level of tendency, nematodes were observed to enhance the cockroaches’ growth rates following increase in intensity of the parasitic infection. We found that the two groups of parasites had no effect on one another: the number of gregarines had no effect on the number of specimens of nematodes and vice-versa, the number of nematodes had no effect on the number of gregarine specimens. Perhaps, this is related to different localizations of the parasites: gregarines for most of their life feed in the small intestine, while nematodes feed in the large intestine. Therefore, growth rates of the cockroaches in our experiment have not changed due to the parasites. This indicates minimization of negative effects of gregarines in the midgut and nematodes in the hindgut on the host’s life cycle, developed over long co-evolution.

Fluctuating Starvation Conditions Modify Host-Symbiont Relationship Between a Leaf Beetle and Its Newly Identified Gregarine Species

Gregarines are ubiquitous endosymbionts in invertebrates, including terrestrial insects. However, the biodiversity of gregarines is probably vastly underestimated and the knowledge about their role in shaping fitness-related traits of their host in dependence of fluctuating environmental conditions is limited. Using morphological and molecular analyses, we identified a new gregarine species, Gregarina cochlearium sp. n., in the mustard leaf beetle, Phaedon cochleariae. Applying a full-factorial design, we investigated the effects of a gregarine infection in combination with fluctuating starvation conditions during the larval stage on the development time and fitness-related traits of adult beetles. Under benign environmental conditions, the relationship between gregarines and the host seemed neutral, as host development, body mass, reproduction and survival were not altered by a gregarine infection. However, when additionally exposed to starvation, the combination of gregarine infection and this stress resulted in the lowest reproduction and survival of the host, which points to a parasitic relationship. Furthermore, when the host experienced starvation, the development time was prolonged and the adult females were lighter compared to non-starved individuals, independent of the presence of gregarines. Counting of gregarines in the guts of larvae revealed a lower gregarine load with increasing host body mass under stable food conditions, which indicates a regulation of the gregarine burden in dependence of the host condition. Contrary, in starved individuals the number of gregarines was the highest, hence the already weakened host suffered additionally from a higher gregarine burden. This interactive effect between gregarine infection and fluctuating starvation conditions led to an overall reduced fitness of P. cochleariae. Our study emphasizes the need to study endosymbionts as important components of the natural environment and to investigate the role of host-symbiont relationships under fluctuating environmental conditions in an evolutionary and ecological context.

New Report on The Occurrence of Gregarine Parasites in Wild Species of Macrobrachium rosenbergii from Setiu Lagoon, Terengganu, Malaysia

Highlight ResearchThis is the first report of the occurrence of gregarine species in Peninsular Malaysia.The information of these findings will lead to the identification of species using genetic analysis.This information can help to solve the cultured problem of the Macrobrachium rosenbergii industry worldwide. AbstarctStudies on the parasite of prawn are likely to be important due to the commercial value of the prawn. Investigation study about gregarine parasites of M. rosenbergii in Malaysia is still lacking. Objective of this study is to determine the occurrence of gregarine parasites in shrimp, M. rosenbergii from Setiu Lagoon, Terengganu. The study was done specifically to observe the prevalence and the mean intensity of the parasites which include the morphological prevalence and parasitological study. Prevalence of the parasites in this study is 42.4% with 95% Cumulative Index (CI) 25.6% to 59.3% and value of Odd Ratio (OR) is 0.74 (CI = 0.29 to 1.88). Two structures of the gregarine which is gamont and syzygy found in this study are closely related to morphology characteristic of gregarine in the previous report.

Gregarines (Apicomplexa: Eugregarinorida) parasitizing the cave cricket Troglophilus (Orthoptera: Raphidophoridae) in the Slovenian karst

The cave crickets Troglophilus neglectus Krauss, 1879 and T. cavicola (Kollar, 1833) originating from caves in Slovenia were surveyed for gregarines. Two gregarine species were identified. Gregarina troglophili (Golemansky & Lipa, 1991) occurred in both cave cricket species, T. cavicola being reported a new host species. Besides, a new species, Gregarina bernardae sp. n., in­fecting T. neglectus, was identified and described. The two spe­cies often infest the same T. neglectus individuals, but can be well distinguished upon the shape and morphometric indexes of both solitary gregarines and associations. The deutomerite in solitary gamonts of G. troglophili is orbicular to broadly el­liptoid, while in G. bernardae sp. n. it is oblong to dolioform. In associations, the primite deutomerite in G. troglophili is orbicu­lar to broadly elliptoid, while in G. bernardae sp. n. it is shal­lowly oblong to oblong. In contrast to broadly obovoid to finely obdeltoid satellite deutomerite in G. troglophili, it is narrowly dolioform or dolioform to narrowly obdeltoid in G. bernardae sp. n. Both species are new to the faunal list of Slovenia, and to the list of cave-dwelling species in the country. We direct the attention to the parasite diversity of cave-dwelling animals – a promising, but understudied topic that might considerably contribute to the diversity of the subterranean fauna.

New gregarine species (Apicomplexa) from tunicates show an evolutionary history of host switching and suggest a problem with the systematics of Lankesteria and Lecudina

Apicomplexa (sensu stricto) are a diverse group of obligate parasites to a variety of animal species. Gregarines have been the subject of particular interest due to their diversity, phylogenetically basal position, and more recently, their symbiotic relationships with their hosts. In the present study, four new species of marine eugregarines infecting ascidian hosts (Lankesteria kaiteriteriensis sp. nov., L. dolabra sp. nov., L. savignyii sp. nov., and L. pollywoga sp. nov.) were described using a combination of morphological and molecular data. Phylogenetic analysis using small subunit rDNA sequences suggested that gregarines that parasitize ascidians and polychaetes share a common origin as traditionally hypothesized by predecessors in the discipline. However, Lankesteria and Lecudina species did not form clades as expected, but were instead intermixed amongst each other and their respective type species in the phylogeny. These two major genera are therefore taxonomically problematic. We hypothesize that the continued addition of new species from polychaete and tunicate hosts as well as the construction of multigene phylogenies that include type-material will further dissolve the currently accepted distinction between Lankesteria and Lecudina. The species discovered and described in the current study add new phylogenetic and taxonomic data to the knowledge of marine gregarine parasitism in ascidian hosts.

Gregarine single-cell transcriptomics reveals differential mitochondrial remodeling and adaptation in apicomplexans

BackgroundApicomplexa is a diverse phylum comprising unicellular endobiotic animal parasites and contains some of the most well-studied microbial eukaryotes including the devastating human pathogens Plasmodium falciparum and Cryptosporidium hominis. In contrast, data on the invertebrate-infecting gregarines remains sparse and their evolutionary relationship to other apicomplexans remains obscure. Most apicomplexans retain a highly modified plastid, while their mitochondria remain metabolically conserved. Cryptosporidium spp. inhabit an anaerobic host-gut environment and represent the known exception, having completely lost their plastid while retaining an extremely reduced mitochondrion that has lost its genome. Recent advances in single-cell sequencing have enabled the first broad genome-scale explorations of gregarines, providing evidence of differential plastid retention throughout the group. However, little is known about the retention and metabolic capacity of gregarine mitochondria.ResultsHere, we sequenced transcriptomes from five species of gregarines isolated from cockroaches. We combined these data with those from other apicomplexans, performed detailed phylogenomic analyses, and characterized their mitochondrial metabolism. Our results support the placement of Cryptosporidium as the earliest diverging lineage of apicomplexans, which impacts our interpretation of evolutionary events within the phylum. By mapping in silico predictions of core mitochondrial pathways onto our phylogeny, we identified convergently reduced mitochondria. These data show that the electron transport chain has been independently lost three times across the phylum, twice within gregarines.ConclusionsApicomplexan lineages show variable functional restructuring of mitochondrial metabolism that appears to have been driven by adaptations to parasitism and anaerobiosis. Our findings indicate that apicomplexans are rife with convergent adaptations, with shared features including morphology, energy metabolism, and intracellularity.

Molecular phylogeny and new light microscopic data of Metchnikovella spiralis (Microsporidia: Metchnikovellidae), a hyperparasite of eugregarine Polyrhabdina sp. from the polychaete Pygospio elegans.

Metchnikovellids are a deep-branching group of microsporidia, parasites of gregarines inhabiting the alimentary tract of polychaetes and some other invertebrates. The diversity and phylogeny of these hyperparasites remain poorly studied. Modern descriptions and molecular data are still lacking for many species. The results of a light microscopy study and molecular data for Metchnikovella spiralis Sokolova et al., 2014, a hyperparasite of the eugregarine Polyrhabdina sp., isolated from the polychaete Pygospio elegans, were obtained. The original description of M. spiralis was based primarily on the analysis of stained preparations and transmission electron microscopy images. Here, the species description was complemented with the results of in vivo observations and phylogenetic analysis based on the SSU rRNA gene. It was shown that in this species, free sporogony precedes sac-bound sporogony, as it occurs in the life cycle of most other metchnikovellids. Spore sacs are entwined with spirally wound cords, and possess only one polar plug. Phylogenetic analyses did not group M. spiralis with M. incurvata, another metchnikovellid from the same gregarine species, but placed it as a sister branch to Amphiacantha. The paraphyletic nature of the genus Metchnikovella was discussed. The taxonomic summary for M. spiralis was emended.

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.

Distribution patterns of gregarine parasitism of wild marine bivalve, Anadara cornea (reeve, 1844) concerning seasonality and water quality

Gregarines are groups of protozoan parasites that ubiquitously infect arthropods worldwide including host from terrestrial and aquatic environment. To date, 1,600 gregarine species have been described, but less study for invertebrates have been recorded for these apicomplexan parasites. Wild marine bivalve species Anadara cornea (Reeve, 1844) populations were surveyed for gregarines at Setiu Lagoon in Terengganu, Malaysia for a year. This species of bivalve was previously unlisted as hosts. Malaysia is known as a country that experience with rainy and dry season. The trends of rainfall regime in Peninsular Malaysia is mainly affected by the seasonal monsoon i.e. Southwest (SW) monsoon (May to October) and Northeast (NE) monsoon in November and ends in April the following year. The objective of this study was to associate the incidence of gregarine in common wild bivalves, A. cornea of Setiu Lagoon, Terengganu in relation to water quality and seasons. Gregarine prevalence and mean intensity of infections were compared between seasons. Samples were collected at seagrass beds which contain sandy muddy area which is a suitable habitat for this bivalve. The study was conducted from January to December 2018 with a total of 480 sample bivalve collected (n=40 per month). Total numbers of parasites were counts during this study were 33,239 phagocytes. The highest intensity of the infection of the parasite was found in November (n=5014) and the lowest number of infection was in January (n=767). The confidence interval for proportions normal approximation in the prevalence of dry season was 48.9% with 95% of CI=45.3%–54.3%. The confidence interval for proportions normal approximation in the prevalence of rainy season was 47.7% with 95% of CI=43.2%– 52.2%. Risk estimation for odds ratio (OR) was 0.087 with 95% CI=0.01-0.68 Pearson Chi-Square showed the significant value (p≤0.05) cases via season. Most of the site infections of this parasite were on gill and digestive tract. Prevalence of parasites was considerably the same for both seasons. The mean intensity levels of infections were slightly high during the rainy season, which was assumed characterized by low surface seawater temperature, low salinity, and high levels of rainfall. Regression analyses revealed that season was significantly related to gregarine prevalence and intensity. This result emphasizes the importance of considering season and habitat as a part of the consideration factor while studying gregarine in bivalve ecology.

Hardware – wheat pests as elements of the species consortium

Annually in the world, insect pests kill 10–15 % of the crop yield, which in the face of increasing humanity creates a global problem for food security. For the territory of Ukraine in some years, the loss of wheat yields reach 25 % and, in the face of this tendency, real risks to the security of the state are created. Considering that the agrarian trend of the state development has been increasing in recent years, the development of grain-adapted to the ecological and climatic conditions of Ukraine is a priority direction of the development of domestic agriculture. And the development of new environmentally friendly methods of controlling pests of wheat using parasitic organisms will become a fundamentally new and pressing issue in the development of organic production in the country. The general list of pest species that can cause serious wheat yield and forage reduction in Ukraine includes more than 230 names, but only 18 species are able toentail the biggest losses. Among them belong to the order Coleoptera. One insect species is usually a host of several species of mites, nematodes and up to ten species of gregarines and microsporidia. Unfortunately, the taxonomic composition of parasites of phytophagous pets of wheat in Ukraine has not been thoroughly investigated. We studied the interrelation between parasites of 4 phytophagous insects of wheat as well as of 14 insect species found in granaries. The study of the species composition of parasitic organisms of wheat and grain pests is based on the study of the elementary part of the consortium ecosystem, where they act as second order consortia. Phytophagous parasites of wheat and collar pests of cereals, as second-order consorts, have been fragmented worldwide. The purpose of this work is to determine the species composition of gregarine as a component of wheat consortium for their further use in the creation of integrated methods of protection of wheat and products of its processing. As a result, 28 species of gregarines were registered, which belong to seven families (Didymophyidae, Ophryocystidae, Hirmocystidae, Lipotrophidae, Stylocephalidae, Actinocephalidae and Gregarinidae). On the average, 1–2 species of gregarines parasitize in one pest species. 7–10 species of parasites were identified in some insects of the family Tenebrionidae (Tenebrio molitor Linnaeus, 1758 and Tribolium confusum Jacquelin du Val, 1863). Each presented parasite is characteristic of 1–2 species of pests, but there are species of gregarines that infect up to four species of model species, such as Gregarina cuneata Stein, 1848. The largest number of individuals who are infested with gregarines belong to such families as Tenebrionidae and Dermestidae (38,6 % and 36,0 % of the total number of species, respectively). On pests – phytophages parasitizes about 8 species of gregarine families Stylocephalidae, Gregarinidae, Actinocephalidae. For barns pests are recorded barnacles of all 7 families.

Gregarine Oocyst Production is a Function of Gametocyst Size

Gregarine transmission depends upon the environmental encounter rate between viable infective oocysts and suitable hosts. Many factors determine the abundance and distribution of gregarine oocysts in the environment, but the primary factors are oocyst distribution, environmental persistence, and production rate. Prior studies have demonstrated factors affecting oocyst distribution and environmental persistence, but oocyst production rate is poorly understood. This study addresses the effects of gametocyst size on oocyst production. For each of 3 gregarine species, gametocyst size was determined, and the subsequent oocyst production of each gametocyst was quantified. Gregarine species with larger gametocysts produced more oocysts per gametocyst than species with smaller gametocysts. Likewise, within species, larger gametocysts produced more oocysts. The effect was stronger in larger gregarine species, probably as a reflection of the lower overall range of gametocyst size in the smaller gregarine species.

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

Protozoa, of the taxon Gregarinasina, are a heterogeneous group of Apicomplexa that includes ~1600 species. They are parasites of a large variety of both marine and terrestrial invertebrates, mainly annelids, arthropods and mollusks. Unlike coccidians and heamosporidians, gregarines have not proven to have a negative effect on human welfare; thus, they have been poorly investigated. This study focuses on the molecular identification and phylogeny of the gregarine species found in the midgut of two insect species that are considered as an alternative source of animal proteins for the human diet: the mealworm Tenebrio molitor, and the super-worm Zophobas atratus (Coleoptera: Tenebrionidae). Gregarine specimens were isolated from the gut of both larval and adult stages of T. molitor specimens, as well as from Z. atratus larvae. The morphological analyses were restricted to the identification of the different parasite morpho-types, likely corresponding either to different life-cycle stages or to alternative gregarine species. The samples were also used for the DNA extraction necessary for their genetic characterization. Finally, the efficiency of different molecular markers (i.e., 18S rDNA gene alone or combined with the Internal Transcribed Spacer 1) was assessed when applied either to gregarine species identification and to phylogenetic inference.

Morphology and molecular systematic of marine gregarines (Apicomplexa) from Southwestern Atlantic spionid polychaetes.

Gregarines are a common group of parasites that infect the intestines of marine invertebrates, and particularly polychaetes. Here, we describe for the first time four gregarine species that inhabit the intestines of three spionid species: Dipolydora cf. flava, Spio quadrisetosa and Boccardia proboscidea from the Patagonian coast, Argentina, using light and scanning electron microscopy and molecular phylogenetic analyses of small subunit (SSU) rDNA sequences. Even though the spionid species thrive in the same environments, our results showed a high host specificity of the gregarine species. Selenidium cf. axiferens and Polyrhabdina aff. polydorae were both identified from the intestine of D. cf. flava. The new species, Polyrhabdina madrynense sp. n. and Selenidium patagonica sp. n., were described from the intestines of S. quadrisetosa and the invasive species B. proboscidea, respectively. All specimens of D. cf. flava and S. quadrisetosa were infected by gregarines (P = 100%), recording the highest mean intensity values of infection (MI = 80; 60 respectively), in contrast to B. proboscidea (P = 60%; MI = 38). We associated this finding with the recent invasion of this host. It is expected that in the future, an increase of its population density might favour a rising intensity of this gregarine infection.