Gregarina triboliorum (Eugregarinida: Gregarinidae) n. sp. from Tribolium confusum and resolution of the confused taxonomic history of Gregarina minuta Ishii, 1914.
ABSTRACT The septate gregarine parasites of flour beetles (Tribolium spp.) include Gregarina minuta Ishii, 1914, a relatively small species in which both primite and satellite possess an obvious protomerite, and a larger species that lacks the satellite protomerite. The latter species has been placed in the genera Didymophyes and Hirmocystis by various authors, but studies reported here demonstrate that this species, herein described as Gregarina triboliorum, exhibits early pairing and produces oocyst chains, both characteristics of the genus Gregarina. The oocysts of this new species are described for the first time. In addition, experimental infections using oocyst from single gametocysts reveal that oocyst chain number is variable but is typically 1, 2, or 4. Prior experiments involving a related beetle, Tenebrio molitor, demonstrated extreme host specificity within the 4 Gregarina species parasitizing larval and adult hosts. However, G. triboliorum is not limited either stadially or specially, infecting both adults and larvae of Tribolium confusum and Tribolium castaneum.
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ABSTRACT: Theoretical demographic models with accompanying experimental programs provide an important framework to study the life history of organisms. In this paper we examine the fitness characteristics of gregarine parasites (Apicomplexa) and how these evolutionary long-lived parasites are shaped by their own life cycle stages inside and outside a definitive insect host. Although gregarines have been investigated in experimental works, their fitness and population characteristics have not been subject to modeling efforts to help understand their longevity or interactions with their host species. We develop a dynamic, mechanistic population model represented by a system of two differential equations for two of the parasite stages: the mature parasite, or trophont, inside a definitive insect host, and the infectious oocyst stage in the water environment of the host. In contrast to many classical macroparasite models, the force of infection between oocysts and hosts is of sigmoid type. Inside the host, production of the water borne infectious state is modeled by linear production rate in the trophont population with a density-independent trophont mortality. We examine stability of model's equilibria for different parameter values and different host populations. This leads to the definition of a fitness parameter that acts as a bifurcation parameter for the model. The model shows good cause for the establishment and long-time persistence of this common, widespread parasite. It is parameterized by extensive data gathered at Cedar Point Biological Station, and numerical calculations based on those parameters illustrate the dynamics. Possible applications include parasite control in aquacultures.Ecological Modelling 05/2012; 233:31–40. · 2.07 Impact Factor
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ABSTRACT: A phylogenetic hypothesis was constructed with the use of ssu rDNA sequence data from 27 eugregarine species parasitizing a variety of arthropod hosts and habitats. The data were used to address higher-level character transitions, identify clades, recognize supraspecific taxonomic groups, assess the existing gregarine classification, and assess the effects of host metabolic pattern and habitat transitions on the radiation of the septatorinid gregarines. Suprageneric character transitions for association form, association timing, syzygy, gametocyst dehiscence, and oocyst liberation are defined. New character search based on the proposed phylogeny produced a morphological character set that correlates strongly with the sequence data. These morphological character sets are mapped to the new septatorinid phylogeny. Existing superfamily groups within Septatorina were recovered and a new superfamily recognized. At the family level, the monophyly of Actinocephalidae and Stylocephalidae is confirmed and the polyphyly of Gregarinidae is partially resolved with the recognition of Blabericolidae. At the generic level, the monophyly of Protomagalhaensia and Xiphocephalus is confirmed, the polyphyly of Leidyana is partially resolved with the recognition of Blabericola, and the polyphyly of Gregarina is revealed but cannot be resolved without additional taxonomic data. High-level diversification of Septatorina resulted from adaptations of the gametocyst, allowing colonization of both terrestrial and sweet-water habitats. Major radiations within the group correlate with host metamorphic pattern, suggesting that evolutionarily, gregarine species track niche resources along lines of transmission; they do not necessarily track host species in evolutionary time. Gregarine assemblages within a single host species may be either vicariant assemblages, (i.e., products of coevolutionary, phylogenetic effects), or ecotypic assemblages, (i.e., products of ecological fitting and host switching). The following systematic or nomenclatural acts are committed. Stenophoroidea and Gregarinoidea are emended. Diagnoses of Stenophoroidea, Gregarinoidea, and Sphaerocystidae are revised. Stylocephaloidea n. supfam., Blabericolidae n. fam., and Blabericola n. gen. are recognized and erected. Blabericola princisi n. comb., Blabericola cubensis n. comb., Blabericola haasi n. comb., and Blabericola migrator n. comb. are recognized. Schneideria, Neoschneideria, and Paraschneideria are removed from Sphaerocystidae and placed in Actinocephalidae. Protomagalhaensia is removed from Hirmocystidae and placed in Blabericolidae. Pyxinia is removed from Stylocephaloidea: Actinocephalidae and placed in Stenophoroidea: Monoductidae. Blabericola haasi, Blabericola migrator, Blabericolidae, Colepismatophila watsonae, Eugregarinorida, Geneiorhynchus manifestus, Gregarina basiconstrictonea, Gregarina blattarum, Gregarina coronata, Gregarina cuneata, Gregarina diabrotica, Gregarina kingi, Gregarina niphandrodes, Gregarina polymorpha, Gregarina tropica, Gregarine, Gregarinidae, Gregarinoidea, Hirmocystidae, Hoplorhynchus acanthatholius, Leidyana erratica, Monoductidae, Neoschneideria, Paraschneideria, Paraschneideria metamorphosa, phylogeny, Prismatospora evansi, Protomagalhaensia, Protomagha- lensia granulosae, Protomaghalensia wolfi, Pyxinia crystalligera, Schneideria, Septatorina, Sphaerocystidae, Stenophora robusta, Stenophoroidea, Stylocephalidae, Stylocephaloidea, Stylocephalus giganteus, Xiphocephalus ellisi, Xiphocephalus triplogemmatus.Comparative Parasitology 08/2009; · 0.74 Impact Factor
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ABSTRACT: Protomagalhaensia wolfi n. comb. and Leidyana haasi n. comb. were originally described as species of Gregarina parasitizing the lobster cockroach, Nauphoeta cinerea, in east Africa. Gamonts of Protomagalhaensia species are elongate and serpentine in general shape. Species within the genus are differentiated primarily by epimerite and oocyst morphology. Among described species of Protomagalhaensia, only P. wolfi possesses an obdeltoid epimerite. The oocysts of P. wolfi possess no apical spine or knob and are notably larger than oocysts of other species in the genus. Among the 33 species of Leidyana, only L. haasi and Leidyana migrator are reported from cockroaches (Dictyoptera). In general, gamonts of L. migrator are longer and more anisometric than those of L. haasi, the greater length reflecting notably longer deutomerites in L. migrator. The gamontic protomerites of L. haasi are longer but considerably narrower than those of L. migrator even though gamonts of L. migrator are larger overall. Both L. migrator and L. haasi are characterized by elliptoid oocysts that differ in relative morphology and overall size. The elliptoid gametocysts of L. migrator are ca. 3 times larger than those of L. haasi. We redescribe P. wolfi and L. haasi and refer them to genera other than Gregarina, establish neotype specimens, revise the diagnosis of Protomagalhaensia to reflect oocyst variation within the genus and distinguish it from the other 15 genera comprising Hirmocystidae, and discuss the fidelity of endemic gregarine faunas with their cockroach hosts despite global host dispersal.Comparative Parasitology 01/2009; · 0.74 Impact Factor