Rapid divergence, molecular evolution, and morphological diversification of coastal host-parasite systems from southern Brazil

Parasitology ◽  
2019 ◽  
Vol 146 (10) ◽  
pp. 1313-1332 ◽  
Author(s):  
Marlus Bueno-Silva ◽  
Walter A. Boeger
Keyword(s):  
Molecular Evolution ◽  
Dna Sequences ◽  
Host Species ◽  
Geographic Distance ◽  
Morphological Differentiation ◽  
The Body ◽  
Brazilian Coast ◽  
Genetic Structuring ◽  
Morphological Diversification ◽  
Host Parasite

AbstractThis study assessed the role of historical processes on the geographic isolation, molecular evolution, and morphological diversification of host-parasite populations from the southern Brazilian coast. Adult specimens of Scleromystax barbatus and Scleromystax macropterus were collected from the sub-basin of the Nhundiaquara River and the sub-basin of the Paranaguá Bay, state of Paraná, Brazil. Four species of Gyrodactylus were recovered from the body surface of both host species. Morphometric analysis of Gyrodactylus spp. and Scleromystax spp. indicated that subpopulations of parasites and hosts could be distinguished from different sub-basins and locations, but the degree of morphological differentiation seems to be little related to geographic distance between subpopulations. Phylogenetic relationships based on DNA sequences of Gyrodactylus spp. and Scleromystax spp. allowed distinguishing lineages of parasites and hosts from different sub-basins. However, the level of genetic structuring of parasites was higher in comparison to host species. Evidence of positive selection in mtDNA sequences is likely associated with local adaptation of lineages of parasites and hosts. A historical demographic analysis revealed that populations of Gyrodactylus and Scleromystax have expanded in the last 250 000 years. The genetic variation of parasites and hosts is consistent with population-specific selection, population expansions, and recent evolutionary co-divergence.

Distribution of Pomphorhynchus laevis s.l. (Acanthocephala) among fish species at a local scale: importance of fish biomass density

2019 ◽  
Vol 94 ◽  
Author(s):  
M.-J. Perrot-Minnot ◽  
L. Bollache ◽  
C. Lagrue
Keyword(s):  
Fish Species ◽  
Host Species ◽  
Fish Host ◽  
The Body ◽  
Fundamental Aspect ◽  
Fish Biomass ◽  
Biomass Density ◽  
Pomphorhynchus Laevis ◽  
Main Driver ◽  
Host Parasite

Abstract Parasite distribution among hosts is a fundamental aspect of host–parasite interactions. Aggregated parasite distributions within and across host species are commonly reported and potentially influenced by many factors, whether host or parasite specific, or related to host–parasite encounter and compatibility. Yet, the respective role of each in observed parasite distributions are often unclear. Here, we documented the distribution of the acanthocephalan parasite Pomphorhynchus laevis sensu lato (s.l.) in two replicate fish host populations. Aggregated distributions were observed in both populations, within and across fish host species. We found a positive abundance–prevalence relationship across fish species, suggesting that resource availability (fish host biomass density) was the main driver of P. laevis s.l. distribution. This was supported by further positive associations between mean parasite load and fish biomass density. We found little evidence for intensity-dependent regulation within host (i.e. intra-host competition among co-infecting parasites). Furthermore, P. laevis s.l. infection had no detectable effect on fish condition indices, except on the body condition of female barbel (Barbus barbus). Therefore, P. laevis s.l. tended to accumulate with size/age within fish species, and with fish biomass density among fish species, with apparently negligible limitations due to intra-host intensity-dependent regulation of parasite, or to parasite-induced morbidity in fish. The relative availability of final hosts for trophic transmission thus appears to be the main driver of P. laevis s.l. distribution among fish.

scholarly journals Potential host ranges of three Asian larval parasitoids of Drosophila suzukii

2021 ◽  
Author(s):  
Kent M. Daane ◽  
Xingeng Wang ◽  
Brian N. Hogg ◽  
Antonio Biondi
Keyword(s):  
Body Size ◽  
Host Species ◽  
Classical Biological Control ◽  
Developmental Time ◽  
The Body ◽  
Phylogenetic Position ◽  
Egg Load ◽  
Drosophila Suzukii ◽  
Larval Parasitoids ◽  
Female Body Size

AbstractAsobara japonica (Hymenoptera: Braconidae), Ganaspis brasiliensis and Leptopilina japonica (Hymenoptera: Figitidae) are Asian larval parasitoids of spotted wing drosophila, Drosophila suzukii (Diptera: Drosophilidae). This study evaluated these parasitoids’ capacity to attack and develop from 24 non-target drosophilid species. Results showed that all three parasitoids were able to parasitize host larvae of multiple non-target species in artificial diet; A. japonica developed from 19 tested host species, regardless of the phylogenetic position of the host species, L. japonica developed from 11 tested species; and G. brasiliensis developed from only four of the exposed species. Success rate of parasitism (i.e., the probability that an adult wasp successfully emerged from a parasitized host) by the two figitid parasitoids was low in hosts other than the three species in the melanogaster group (D. melanogaster, D. simulans, and D. suzukii). The failure of the figitids to develop in most of the tested host species appears to correspond with more frequent encapsulation of the parasitoids by the hosts. The results indicate that G. brasiliensis is the most host specific to D. suzukii, L. japonica attacks mainly species in the melanogaster group and A. japonica is a generalist, at least physiologically. Overall, the developmental time of the parasitoids increased with the host’s developmental time. The body size of female A. japonica (as a model species) was positively related to host size, and mature egg load of female wasps increased with female body size. We discuss the use of these parasitoids for classical biological control of D. suzukii.

scholarly journals Morphological and Genetic Structure of Two Equivalent Astyanax Species (Characiformes: Characidae) in the Region of Paranaíba Arc

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Renan Rodrigues Rocha ◽  
Rosana de Mesquita Alves ◽  
Rubens Pasa ◽  
Karine Frehner Kavalco
Keyword(s):  
Geometric Morphometrics ◽  
River Basin ◽  
Dna Sequences ◽  
Haplotype Network ◽  
River Basins ◽  
Molecular Data ◽  
The Body ◽  
Present Species ◽  
Body Depth ◽  
Geometric Morphometric

The Astyanax scabripinnis complex is composed of a large number of almost morphological indistinguishable species, including Astyanax paranae and Astyanax rivularis, which exist in the Paraná and São Francisco Basins, respectively, and sometimes are considered subspecies of the A. scabripinnis group or even are cited just as A. scabripinnis. The two river basins are separated by the Upper Paranaíba Arc, likely the main cause of the isolation of these species. We used geometric morphometric tools and DNA analyses of populations of both species to identify the differences between them. Geometric morphometrics separated the two species into distinct groups, whose main difference was the body depth. This is generally related to the speed of the water flow in the river basins. The maximum likelihood phylogram based on mitochondrial DNA sequences formed two main clades: one composed of the population of A. rivularis and the other, of A. paranae. In the haplotype network, the species were similarly separated into two groups from the same ancestral haplotype, with A. rivularis dispersing into two lineages in the São Francisco River Basin. The distribution of A. paranae is a consequence of a secondary dispersion event in the Paraná River Basin. It forms two lineages from a haplotype derived from the ancestor. The vicariant effect of separate basins, through the elevation of the Upper Paranaíba Arc, led to the allopatric speciation of the populations originating the present species. The results of geometric morphometrics and molecular data of the fish show the importance of this geological event in the biogeography and evolutionary history of the ichthyofauna of the region and indicate that the isolation of these species seems to be effective.

Molecular evolution of homologous gene sequences in germline-limited and somatic chromosomes of Acricotopus

Genome ◽  
2004 ◽  
Vol 47 (4) ◽  
pp. 732-741 ◽  
Author(s):  
Wolfgang Staiber
Keyword(s):  
Molecular Evolution ◽  
Dna Sequences ◽  
Sequence Data ◽  
Structural Evolution ◽  
5S Rdna ◽  
Oligonucleotide Primer ◽  
Homologous Gene ◽  
Gene Sequences ◽  
Nucleotide Substitutions ◽  
Degenerate Oligonucleotide

The origin of germline-limited chromosomes (Ks) as descendants of somatic chromosomes (Ss) and their structural evolution was recently elucidated in the chironomid Acricotopus. The Ks consist of large S-homologous sections and of heterochromatic segments containing germline-specific, highly repetitive DNA sequences. Less is known about the molecular evolution and features of the sequences in the S-homologous K sections. More information about this was received by comparing homologous gene sequences of Ks and Ss. Genes for 5.8S, 18S, 28S, and 5S ribosomal RNA were choosen for the comparison and therefore isolated first by PCR from somatic DNA of Acricotopus and sequenced. Specific K DNA was collected by microdissection of monopolar moving K complements from differential gonial mitoses and was then amplified by degenerate oligonucleotide primer (DOP)-PCR. With the sequence data of the somatic rDNAs, the homologous 5.8S and 5S rDNA sequences were isolated by PCR from the DOP-PCR sequence pool of the Ks. In addition, a number of K DOP-PCR sequences were directly cloned and analysed. One K clone contained a section of a putative N-acetyltransferase gene. Compared with its homolog from the Ss, the sequence exhibited few nucleotide substitutions (99.2% sequence identity). The same was true for the 5.8S and 5S sequences from Ss and Ks (97.5%–100% identity). This supports the idea that the S-homologous K sequences may be conserved and do not evolve independently from their somatic homologs. Possible mechanisms effecting such conservation of S-derived sequences in the Ks are discussed.Key words: microdissection, DOP-PCR, germline-limited chromosomes, molecular evolution.

scholarly journals Host-parasite relationship during Epistylis sp. (Ciliophora: Epistylididae) infestation in farmed cichlid and pimelodid fish

2016 ◽  
Vol 51 (5) ◽  
pp. 520-526 ◽  
Author(s):  
Santiago Benites de Pádua ◽  
Maurício Laterça Martins ◽  
Gustavo Moraes Ramos Valladão ◽  
Laura Utz ◽  
Fernando José Zara ◽  
...  
Keyword(s):  
The Body ◽  
Farmed Fish ◽  
Hydropic Degeneration ◽  
Ulcer Disease ◽  
Opportunistic Bacteria ◽  
Parasite Relationship ◽  
Hemorrhagic Ulcer ◽  
Host Parasite ◽  
Portal Of Entry

Abstract: The objective of this work was to describe the host-Epistylis sp. relationship during infestation on farmed fish. Five Nile tilapia (Oreochromis niloticus) and ten hybrid surubim catfish (Pseudoplatystoma reticulatum x P. corruscans), all diseased, were used for in vivo morphological analysis of sessile peritrichs by contrast microscopy. Fragments of infected tissues were subjected to histological processing and scanning electron microscopy. Epistylis sp. caused hemorrhagic ulcer disease, and cichlids were more prone to develop infestations throughout the body surface due to the attachment of the colonies to the scales, which did not occur with pimelodids. Multifocal granulomatous dermatitis was observed, associated with the hydropic degeneration of the epithelium and to ulcerative areas of necrosis. Microscopic examination showed the presence of bacterial microflora associated to Epistylis sp. peduncles. Therefore, this species can be considered a portal of entry for opportunistic bacteria.

Integrative taxonomic methods reveal an incorrect synonymisation of the South African Pseudonereis podocirra (Schmarda) as the widespread Pseudonereis variegata (Grube) from Chile

2018 ◽  
Vol 32 (6) ◽  
pp. 1282 ◽  
Author(s):  
Jyothi Kara ◽  
Angus H. H. Macdonald ◽  
Carol A. Simon
Keyword(s):  
South Africa ◽  
South African ◽  
Species Delimitation ◽  
Haplotype Network ◽  
The Body ◽  
General Description ◽  
The South ◽  
Morphological Examination ◽  
Genetic Structuring ◽  
The Status

The nereidid Pseudonereis variegata (Grube, 1866) described from Chile includes 14 synonymised species from 10 type localities with a discontinuous distribution, but no taxonomic or molecular studies have investigated the status of this species outside Chile. Two synonymised species, Mastigonereis podocirra Schmarda, 1861 and Nereis (Nereilepas) stimpsonis Grube, 1866, were described from South Africa and investigated here using morphological examination. MtCOI species delimitation analyses and morphology were used to determine the status of P. variegata in South Africa. Morphological examination revealed that museum and freshly collected specimens from South Africa that conform to the general description of P. variegata are similar to M. podocirra and N. stimpsonis with respect to the consistent absence of homogomph spinigers in the inferior neuropodial fascicle, expanded notopodial ligules and the subterminal attachment of dorsal cirri in posterior parapodia. The synonymy of M. podocirra and N. stimpsonis as P. variegata are rejected and P. podocirra, comb. nov. is reinstated. Morphologically, Pseudonereis podocirra differed from specimens from Chile with regard to the numbers of paragnaths, the absence of homogomph spinigers and changes in parapodial morphology along the body. Independence of these species was further supported by genetic distances, automatic barcode gap discovery and multi-rate Poisson tree process species delimitation analyses of 77 mtCOI sequences. Haplotype network revealed no genetic structuring within the South African populations. http://zoobank.org/urn:lsid:zoobank.org:pub:F0B1A5AF-9CE9-4A43-ACCF-17117E1C2F21

scholarly journals A new species of Xylophis Beddome, 1878 (Serpentes: Pareidae) from the southern Western Ghats of India

2021 ◽  
Vol 71 ◽  
pp. 219-230
Author(s):  
Surya Narayanan ◽  
Pratyush P. Mohapatra ◽  
Amirtha Balan ◽  
Sandeep Das ◽  
David J. Gower
Keyword(s):  
Phylogenetic Analysis ◽  
New Species ◽  
Genetic Distance ◽  
Dna Sequences ◽  
Western Ghats ◽  
White Collar ◽  
The Body ◽  
Western Ghats Of India ◽  
Southern Western Ghats ◽  
A New Species

We reassess the taxonomy of the Indian endemic snake Xylophis captaini and describe a new species of Xylophis based on a type series of three specimens from the southernmost part of mainland India. Xylophis deepakisp. nov. is most similar phenotypically to X. captaini, with which it was previously confused. The new species differs from X. captaini by having a broader, more regular and ventrally extensive off-white collar, more ventral scales (117–125 versus 102–113), and by lack of flounces on the body and proximal lobes of the hemipenis. Phylogenetic analysis of mitochondrial 16S DNA sequences strongly indicates that the new species is most closely related to X. captaini, differing from it by an uncorrected pairwise genetic distance of 4.2%. A revised key to the species of Xylophis is provided.

scholarly journals Model-based inference of punctuated molecular evolution

2019 ◽  
Author(s):  
Marc Manceau ◽  
Julie Marin ◽  
Hélène Morlon ◽  
Amaury Lambert
Keyword(s):  
Molecular Evolution ◽  
Dna Sequences ◽  
Temporal Variations ◽  
Multiple Sequence ◽  
Model Combining ◽  
Constant Rate ◽  
Whole Genomes ◽  
Standard Models ◽  
Natural Variance ◽  
Venom Proteins

AbstractIn standard models of molecular evolution, DNA sequences evolve through asynchronous substitutions according to Poisson processes with a constant rate (called the molecular clock) or a time-varying rate (relaxed clock). However, DNA sequences can also undergo episodes of fast divergence that will appear as synchronous substitutions affecting several sites simultaneously at the macroevolutionary time scale. Here, we develop a model combining basal, clock-like molecular evolution with episodes of fast divergence called spikes arising at speciation events. Given a multiple sequence alignment and its time-calibrated species phylogeny, our model is able to detect speciation events (including hidden ones) co-occurring with spike events and to estimate the probability and amplitude of these spikes on the phylogeny. We identify the conditions under which spikes can be distinguished from the natural variance of the clock-like component of molecular evolution and from temporal variations of the clock. We apply the method to genes underlying snake venom proteins and identify several spikes at gene-specific locations in the phylogeny. This work should pave the way for analyses relying on whole genomes to inform on modes of species diversification.

scholarly journals Testing hypotheses of diversification in Panamanian frogs and freshwater fishes using hierarchical approximate Bayesian computation with model averaging

2018 ◽  
Author(s):  
Justin C Bagley ◽  
Michael J Hickerson ◽  
Jerald B Johnson
Keyword(s):  
Freshwater Fish ◽  
Dna Sequences ◽  
Approximate Bayesian Computation ◽  
Bayes Factor ◽  
Fish Assemblages ◽  
Model Averaging ◽  
External Information ◽  
Bayesian Computation ◽  
Genetic Structuring ◽  
Approximate Bayesian

Most Neotropical frog and freshwater fish species sampled to date show phylogeographic breaks along the Pacific coast of the Isthmus of Panama, with lineages in Costa Rica and western Panama isolated from central Panama. We examine temporal patterns of diversification of taxa across this ‘western Panama isthmus’ (WPI) break to test hypotheses about the origin of species geographical distributions and genetic structuring in this region. We tested for synchronous diversification of four codistributed frog taxon-pairs and three fish taxon-pairs sharing the WPI break using hierarchical approximate Bayesian computation with model averaging based on mitochondrial DNA sequences. We also estimated lineage divergence times using full-Bayesian models. Several of our results supported synchronous divergences within the frog and freshwater fish assemblages; however, Bayes factor support was equivocal for or against synchronous or asynchronous diversification. Nevertheless, we infer that frog populations were likely isolated by one or multiple Pliocene–Pleistocene events more recently than predicted by previous models, while fish genetic diversity was structured by Pleistocene events. By integrating our results with external information from geology and elevational sea level modeling, we discuss the implications of our findings for understanding the biogeographical scenario of the diversification of Panamanian frogs and fishes. Consistent with the ‘Bermingham/Martin model’ (Mol. Ecol. 1998, 7: 499-517), we conclude that the regional fish assemblage was fractured by processes shaping isthmian landscapes during the Pleistocene glaciations, including drainage basin isolation during lowered sea levels.

Predicting the potential distribution ofVexillata(Nematoda: Ornithostrongylidae) and its hosts (Mammalia: Rodentia) within America

2012 ◽  
Vol 87 (4) ◽  
pp. 400-408 ◽  
Author(s):  
E.A. Martínez-Salazar ◽  
T. Escalante ◽  
M. Linaje ◽  
J. Falcón-Ordaz
Keyword(s):  
Environmental Factor ◽  
Species Distribution ◽  
Host Species ◽  
Potential Distribution ◽  
Species Distribution Modelling ◽  
Distribution Modelling ◽  
Distributional Patterns ◽  
Suitable Habitats ◽  
Temperature Seasonality ◽  
Host Parasite

AbstractSpecies distribution modelling has been a powerful tool to explore the potential distribution of parasites in wildlife, being the basis of studies on biogeography.Vexillataspp. are intestinal nematodes found in several species of mammalian hosts, such as rodents (Geomyoidea) and hares (Leporidae) in the Nearctic and northern Neotropical regions. In the present study, we modelled the potential distribution ofVexillataspp. and their hosts, using exclusively species from the Geomyidae and Heteromyidae families, in order to identify their distributional patterns. Bioclimatic and topographic variables were used to identify and predict suitable habitats forVexillataand its hosts. Using these models, we identified that temperature seasonality is a significant environmental factor that influences the distribution of the parasite genus and its host. In particular, the geographical distribution is estimated to be larger than that predicted for its hosts. This suggests that the nematode has the potential to extend its geographical range and also its spectrum of host species. Increasing sample size and geographical coverage will contribute to recommendations for conservation of this host–parasite system.

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