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Janovy, John J. - One of the best experts on this subject based on the ideXlab platform.
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Gregarines on a Diet: The Effects of Host Starvation on \u3ci\u3eGregarina confusa\u3c/i\u3e Janovy et al., 2007 (Apicomplexa: Eugregarinida) in \u3ci\u3eTribolium destructor\u3c/i\u3e Uyttenboogaart, 1933 (Coleoptera: Tenebrionidae) Larvae
DigitalCommons@University of Nebraska - Lincoln, 2008Co-Authors: Schreurs Jodi, Janovy, John J.Abstract:This study was designed to explore the nutritional relationship between Gregarina confusa (Apicomplexa: Eugregarinida) parasites and its coleopteran host, Tribolium destructor, by measuring the cytoplasmic density of gregarines in continuously fed larvae, starved larvae, and larvae refed after starvation. Cultures were maintained in a standard media (whole wheat flour:commercial wheat germ:yeast [30:10:1]). Larvae from control and experimental groups were dissected daily for three days then allowed to feed or starve for an additional three days. On day 6, the remaining experimental larvae were divided and placed into two groups; one group remained starved while larvae from the second group were fed a WheatiesR flake. Photographs were taken of the parasites daily and analyzed using ScionImage™. Gregarines from starved larvae were significantly longer and skinnier than those from fed controls, and there was also a significant difference between gregarine deutomerite cytoplasmic densities. Parasites from refed larvae regained cytoplasmic density within 24 hr and showed morphological similarities to those from fed larvae. This study shows that the Tribolium destructor–Gregarina confusa relationship can be manipulated easily through alterations of host diet and thus is an excellent model for use in the study of chemical relationships between parasites and their hosts
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New and Emended Descriptions of Gregarines from Flour Beetles (\u3ci\u3eTribolium\u3c/i\u3e spp. and \u3ci\u3ePalorus subdepressus\u3c/i\u3e: Coleoptera, Tenebrionidae)
DigitalCommons@University of Nebraska - Lincoln, 2007Co-Authors: Janovy, John J., Detwiler, Jillian Tikka, Schwank Samana, Bolek, Matthew G., Knipes Alaine, Langford, Gabriel J.Abstract:The following new gregarine taxa are described from larvae of flour beetles (Coleoptera: Tenebrionidae): AwryGregarina billmani, n. gen., n. sp., from Tribolium brevicornis; Gregarina cloptoni, n. sp., from Tribolium freemani; Gregarina confusa, n. sp., from Tribolilum confusum; and Gregarina palori, n. sp., from Palorus subdepressus. In addition, the description of Gregarina minuta Ishii, 1914, from Tribolium castaneum, is emended. Scanning electron micrograph studies of these species’ oocysts reveal differences in surface architecture. The Gregarina species have oocysts with longitudinal ridges, visible with SEM, whereas AwryGregarina billmani oocysts have fine circumferential striations; surface architecture is the main feature distinguishing the two gregarine genera. Although parasites from adult beetles are not included in the descriptions, adults of all host species can be infected experimentally using oocysts from the new taxa
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\u3ci\u3eGregarina niphandrodes\u3c/i\u3e (Eugregarinorida: Septatorina): Oocyst Surface Architecture
DigitalCommons@University of Nebraska - Lincoln, 2007Co-Authors: Janovy, John J., Detwiler, Jillian Tikka, Schwank Samana, Bolek, Matthew G., Knipes Alaine, Langford, Gabriel J.Abstract:The surface architecture of oocysts produced by Gregarina niphandrodes (Eugregarinorida) from Tenebrio molitor,/i\u3e adults (Coleoptera: Tenebrionidae) as revealed by scanning electron microscopy is reported. Gametocysts were allowed to dehisce on 15-mm, round cover glasses; the cover glasses with their oocysts chains were then mounted on stubs without further processing, and sputter-coated with 20-nm gold-palladium. Scanning electron microscopy was performed at 10-15 kV with a Hitachi 3000N SEM. Oocysts retained their characteristic shapes as reported in the original species description but showed longitudinal ridges of relatively uniform height, width, and spacing, in separate fields on either side of a central equatorial bulge in the oocysts. There was no ultrastructural evidence of an enclosing external sheath holding the oocysts in a chain. Oocyst ends were flared slightly, and the chain itself was twisted, with adjacent oocysts offset slightly from one another. This article now provides an additional set of structural characters potentially useful in gregarine systematics
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The Response of \u3ci\u3eGregarina niphandrodes\u3c/i\u3e (Apicomplexa: Eugregarinida: Septatina) to Host Starvation in \u3ci\u3eTenebrio molitor\u3c/i\u3e (Coleoptera: Tenebrionidae) Adults
DigitalCommons@University of Nebraska - Lincoln, 2001Co-Authors: Schawang, Jennifer E., Janovy, John J.Abstract:Numerous studies of host starvation have emphasized pathological effects of parasites on their insect host, but little attention has been focused on the effects of host starvation on the parasites. This study addressed the possibility that parasite life-cycle events could be manipulated by withholding food from the host. The system used was Gregarina niphandrodes (Apicomplexa: Eugregarinida) in Tenebrio molitor (Coleoptera: Tenebrionidae) adults. Gregarine gametocyst formation and shedding ceased after one day in starved beetles but continued in fed controls. There were no statistically significant differences between total lengths of associated (3 of 5 trials) or unassociated (5 of 5 trials) gregarines found between experimental and control groups, but average numbers of the two life cycle events were generally higher in fed hosts than in starved ones. If infected, fed control beetles continued to form gametocysts throughout the 7-day trial periods, and gametocysts could be observed in the gut. Starved experimental beetles had no gametocysts in their guts. Refeeding of starved beetles after four days resulted in resumption of gametocyst formation and shedding. The studies demonstrated that the gregarine life cycle could be stopped and then started at the gametocyst formation stage like an off/on switch, simply by withholding food from, then refeeding, the host
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\u3ci\u3eGregarina triboliorum\u3c/i\u3e (Eugregarinida: Gregarinidae) n. sp. from \u3ci\u3eTribolium confusum\u3c/i\u3e and Resolution of the Confused Taxonomic History of \u3ci\u3eGregarina minuta\u3c/i\u3e Ishii, 1914
DigitalCommons@University of Nebraska - Lincoln, 1997Co-Authors: Watwood Stephanie, Janovy, John J., Peterson Erica, Addison, Mary AnnAbstract: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 oocysts from single gametocysts reveal that oocyst chain number is variable but is typically one, two or four. Prior experiments involving a related beetle, Tenebrio molitor, demonstrated extreme host specificity within the four 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
Marie Pierre Chapuis - One of the best experts on this subject based on the ideXlab platform.
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Integrative taxonomy confirms that Gregarina garnhami and G. acridiorum (Apicomplexa, Gregarinidae), parasites of Schistocerca gregaria and Locusta migratoria (Insecta, Orthoptera), are distinct species
Parasite, 2021Co-Authors: Isabelle Florent, Marie Pierre Chapuis, Amandine Labat, Julie Boisard, Nicolas Lemenager, Bruno Michel, Isabelle Desportes-livageAbstract: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.
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integrative taxonomy confirms that Gregarina garnhami and g acridiorum apicomplexa gregarinidae parasites of schistocerca gregaria and locusta migratoria insecta orthoptera are distinct species
Parasite, 2021Co-Authors: Isabelle Florent, Marie Pierre Chapuis, Amandine Labat, Julie Boisard, Nicolas Lemenager, Bruno Michel, Isabelle DesporteslivageAbstract: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 (Forsskal, 1775) was considered by Lipa et al. in 1996 to be synonymous with Gregarina acridiorum (Leger 1893), a parasite of several orthopteran species including Locusta migratoria (Linne, 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.
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subspecific taxonomy of the desert locust schistocerca gregaria orthoptera acrididae based on molecular and morphological characters
Systematic Entomology, 2016Co-Authors: Marie Pierre Chapuis, Corinna S Bazelet, Laurence Blondin, Antoine Foucart, Renaud Vitalis, Michael J SamwaysAbstract:We evaluated the validity of the subspecific designation for Schistocerca gregaria gregaria (Forskal) and Schistocerca gregaria flaviventris (Burmeister), isolated in distinct regions along the north–south axis of Africa. Towards this goal, we assessed the variation of multiple morphological and molecular traits within species. We first used elliptic Fourier and landmark-based relative warps analyses to compare the size and shape of two internal and two external structures of male genitalia. We provide a discriminant function which classified the specimens with 100% accuracy and selected shape elements of the external structures only (cercus and epiproct). We also tested eight molecular markers, and because of either absence of variation or contamination by mitochondrial DNA (mtDNA)-like sequences, we used a clone-and-sequence analysis of the standard cytochrome c oxidase subunit I mitochondrial DNA barcode only. We differentiated 185 true mitochondrial sequences from 66 mitochondrial DNA-like sequences, most of which were from S. g. gregaria specimens. On the dataset of mitochondrial origin, we identified three characteristic point mutations that diagnosed the two allopatric subspecies with 94% accuracy. Minimum spanning network and parsimony tree analyses identified S. g. flaviventris as a monophyletic lineage distinct from the nominate subspecies. Accordingly, microsatellite data indicate rarely occurring admixture events only, showing that independent evolutionary history is the norm. (Resume d'auteur)
Michael J Samways - One of the best experts on this subject based on the ideXlab platform.
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subspecific taxonomy of the desert locust schistocerca gregaria orthoptera acrididae based on molecular and morphological characters
Systematic Entomology, 2016Co-Authors: Marie Pierre Chapuis, Corinna S Bazelet, Laurence Blondin, Antoine Foucart, Renaud Vitalis, Michael J SamwaysAbstract:We evaluated the validity of the subspecific designation for Schistocerca gregaria gregaria (Forskal) and Schistocerca gregaria flaviventris (Burmeister), isolated in distinct regions along the north–south axis of Africa. Towards this goal, we assessed the variation of multiple morphological and molecular traits within species. We first used elliptic Fourier and landmark-based relative warps analyses to compare the size and shape of two internal and two external structures of male genitalia. We provide a discriminant function which classified the specimens with 100% accuracy and selected shape elements of the external structures only (cercus and epiproct). We also tested eight molecular markers, and because of either absence of variation or contamination by mitochondrial DNA (mtDNA)-like sequences, we used a clone-and-sequence analysis of the standard cytochrome c oxidase subunit I mitochondrial DNA barcode only. We differentiated 185 true mitochondrial sequences from 66 mitochondrial DNA-like sequences, most of which were from S. g. gregaria specimens. On the dataset of mitochondrial origin, we identified three characteristic point mutations that diagnosed the two allopatric subspecies with 94% accuracy. Minimum spanning network and parsimony tree analyses identified S. g. flaviventris as a monophyletic lineage distinct from the nominate subspecies. Accordingly, microsatellite data indicate rarely occurring admixture events only, showing that independent evolutionary history is the norm. (Resume d'auteur)
Hans-hinrich Kaatz - One of the best experts on this subject based on the ideXlab platform.
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Analysis of the mitochondrial genome of Schistocerca gregaria gregaria (Orthoptera: Acrididae)
Biological Journal of the Linnean Society, 2010Co-Authors: Silvio Erler, Hans-jörg Ferenz, Robin F. A. Moritz, Hans-hinrich KaatzAbstract:In the present study, we present the full sequence of the mitochondrial genome of the African desert locust Schistocerca gregaria gregaria. The size of 15625 bp reported matches very well with mitochondrial genomes of other Orthopteriodea. The mitochondrial genome comprises 13 protein-coding genes, two ribosomal RNAs and 22 t-RNAs with two t-RNA (trnD and trnK) rearrangements that are typical for the taxon Caelifera. We compared the sequence with 12 mitochondrial genes of Schistocerca gregaria flaviventris and Schistocerca americana and used some of these data to construct phylogenetic trees, which confirm the close relationship between the two subspecies S. g. flaviventris and S. g. gregaria. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 296–305. ADDITIONAL KEYWORDS: gene organization – phylogeny – Schistocerca americana – subspecies.
Christoph Held - One of the best experts on this subject based on the ideXlab platform.
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discrete phenotypes are not underpinned by genome wide genetic differentiation in the squat lobster munida gregaria crustacea decapoda munididae a multi marker study covering the patagonian shelf
BMC Evolutionary Biology, 2016Co-Authors: Chen Wang, Shobhit Agrawal, Jurgen Laudien, Vreni Haussermann, Christoph HeldAbstract:DNA barcoding has demonstrated that many discrete phenotypes are in fact genetically distinct (pseudo)cryptic species. Genetically identical, isogenic individuals, however, can also express similarly different phenotypes in response to a trigger condition, e.g. in the environment. This alternative explanation to cryptic speciation often remains untested because it requires considerable effort to reject the hypothesis that the observed underlying genetic homogeneity of the different phenotypes may be trivially caused by too slowly evolving molecular markers. The widespread squat lobster Munida gregaria comprises two discrete ecotypes, gregaria s. str. and subrugosa, which were long regarded as different species due to marked differences in morphological, ecological and behavioral traits. We studied the morphometry and genetics of M. gregaria s. l. and tested (1) whether the phenotypic differences remain stable after continental-scale sampling and inclusion of different life stages, (2) and whether each phenotype is underpinned by a specific genotype. A total number of 219 gregaria s. str. and subrugosa individuals from 25 stations encompassing almost entire range in South America were included in morphological and genetic analyses using nine unlinked hypervariable microsatellites and new COI sequences. Results from the PCA and using discriminant functions demonstrated that the morphology of the two forms remains discrete. The mitochondrial data showed a shallow, star-like haplotype network and complete overlap of genetic distances within and among ecotypes. Coalescent-based species delimitation methods, PTP and GMYC, coherently suggested that haplotypes of both ecotypes forms a single species. Although all microsatellite markers possess sufficient genetic variation, AMOVA, PCoA and Bayesian clustering approaches revealed no genetic clusters corresponding to ecotypes or geographic units across the entire South-American distribution. No evidence of isolation-by-distance could be detected for this species in South America. Despite their pronounced bimodal morphologies and different lifestyles, the gregaria s. str. and subrugosa ecotypes form a single, dimorphic species M. gregaria s. l.. Based on adequate geographic coverage and multiple independent polymorphic loci, there is no indication that each phenotype may have a unique genetic basis, leaving phenotypic plasticity or localized genomic islands of speciation as possible explanations.
