Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 5 de 5
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Parasitol Int ; 67(6): 829-837, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29753096

RESUMO

A new species of the genus Serpentirhabdias Tkach, Kuzmin et Snyder, 2014, S. moi n. sp., is described from a colubroid snake Chironius exoletus from Caxiuanã National Forest, State of Pará, Brazil. The species is characterised by having a triangular oral opening, absence of the buccal capsule, presence of six minute onchia in the oesophastome, and excretory glands of approximately the same length as the oesophagus. These qualitative morphological characters, as well as some measurements, differentiate the new species from other Neotropical and Nearctic Serpentirhabdias spp. The morphological description of parasitic adults of S. moi n. sp. is complemented by the description of free-living stages including males, females, and infective larvae. Comparative analysis of partial sequences of cox1 and 12S mitochondrial genes strongly supported the status of S. moi n. sp. as a new species. Molecular phylogeny based on sequences of the nuclear DNA region spanning the 3' end of the 18S nuclear rRNA gene, ITS region (ITS1 + 5.8S + ITS2) and 5' end of the 28S gene supported monophyly of all rhabdiasid genera included in the analysis and placed the new species into the Serpentirhabdias clade as sister taxon to S. fuscovenosa.


Assuntos
Colubridae , Interações Hospedeiro-Parasita , Rhabdiasoidea/fisiologia , Infecções por Rhabditida/veterinária , Animais , Brasil/epidemiologia , DNA Espaçador Ribossômico/análise , Feminino , Larva/crescimento & desenvolvimento , Larva/fisiologia , Características de História de Vida , Masculino , Filogenia , RNA Ribossômico 18S/análise , RNA Ribossômico 28S/análise , Rhabdiasoidea/genética , Rhabdiasoidea/crescimento & desenvolvimento , Infecções por Rhabditida/epidemiologia , Infecções por Rhabditida/parasitologia , Análise de Sequência de DNA
2.
Parasitology ; 144(14): 1956-1963, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28805166

RESUMO

In laboratory experiments, we investigated how media with varying ratio of peat:sand and two levels of compaction influence dispersal success of entomopathogenic nematode (EPN) species with different foraging strategies: Steinernema carpocapsae (ambusher), Heterorhabditis downesi (cruiser) and Steinernema feltiae (intermediate). Success was measured by the numbers of nematodes moving through a 4 cm column and invading a wax moth larva. We found that both compaction and increasing peat content generally decreased EPN infective juvenile (IJ) success for all three species. Of the three species, H. downesi was the least affected by peat content, and S. carpocapsae was the most adversely influenced by compaction. In addition, sex ratios of the invading IJs of the two Steinernema species were differentially influenced by peat content, and in the case of S. feltiae, sex ratio was also affected by compaction. This indicates that dispersal of male and female IJs is differentially affected by soil parameters and that this differentiation is species-specific. In conclusion, our study shows that organic matter: sand ratio and soil compaction have a marked influence on EPN foraging behaviour with implications for harnessing them as biological pest control agents.


Assuntos
Interações Hospedeiro-Parasita , Mariposas/parasitologia , Rhabdiasoidea/fisiologia , Solo/química , Strongyloidea/fisiologia , Animais , Larva/crescimento & desenvolvimento , Larva/parasitologia , Mariposas/crescimento & desenvolvimento , Razão de Masculinidade , Especificidade da Espécie
3.
Parasitol Int ; 66(5): 567-572, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28501634

RESUMO

During August 2010, a total of 66 cane toad Rhinella marina were collected in Laguna de Coyuca, Guerrero, Mexico and examined for the presence of helminths. Ninety-two percent were parasitized by 1 or more parasite species. A total of 4624 individuals were found, belonging to 8 helminth taxa (1 digenean, 1 cestode and 6 nematodes). Infracommunities harbored by this host species are highly variable (mean Jaccard similarity index 0.31±0.27); mean percent similarity index 0.26±0.32) and depauperate (mean richness 1.91±0.92; mean abundance 64.4±100.34); almost 50% of them were dominated by Rhabdias fuelleborni, a skin-penetrating nematode. Differences related to host gender and size were found, since males registered infracommunities with lower species richness and diversity than females. The reproductive condition of females (collected during the breeding season) might explain the results obtained; during this season, females invest less in resistance to infection in favor of investing resources in reproduction. However, confirmation of this statement can only be made by sampling in the dry season, when the toads do not reach their reproductive peak.


Assuntos
Bufo marinus/parasitologia , Helmintíase Animal/parasitologia , Helmintos/isolamento & purificação , Helmintos/fisiologia , Animais , Biodiversidade , Meio Ambiente , Feminino , Helmintíase Animal/epidemiologia , Helmintos/classificação , Especificidade de Hospedeiro , Masculino , México/epidemiologia , Reprodução , Rhabdiasoidea/isolamento & purificação , Rhabdiasoidea/fisiologia , Estações do Ano , Pele/parasitologia
4.
Dongwuxue Yanjiu ; 36(3): 119-32, 2015 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-26018855

RESUMO

Mass aggregations and migrations of millipedes despite numerous attempts to find causes for their occurrences are still an enigma. They have been reported from both southern and northern hemisphere countries, from highlands and lowlands of both tropical and temperate regions and they can involve species belonging to the orders Julida and Spirobolida, Polydesmida and Glomerida. According to the main suggestions put forward in the past, mass occurrences in Diplopoda occur: (1) because of a lack of food and a population increase beyond sustainable levels; (2) for the purpose of reproduction and in order to locate suitable oviposition sites; (3) to find overwintering or aestivation sites; (4) because of habitat disruption and changes in the local environment; (5) as a consequence of weather conditions the year (or winter and spring) before. A recent outbreak (November 2014) of a mass migration of the polydesmid Chamberlinius hualienensis Wang 1956 on the Japanese Izu Island of Hachijojima 300 km to the south of Tokyo gave this author an opportunity to review the existing literature on millipede mass migrations and to carry out additional observations on the phenomenon in the field as well as the laboratory. Hitherto unreported heavy infestations with phoretic deutonymphs of the mite Histiostoma sp. as well as dense populations of internal rhabditid nematodes (Oscheius cf. necromena and an unidentified species of the genus Fictor), suggest that infestations of this kind could be necromenic and either have been a contributing factor for the mass migration or been a consequence of so many individuals occurring together at close proximity. It is concluded that mass migrations and aggregations in millipedes do not have one common cause, but represent phenomena that often are seasonally recurring events and appear identical in their outcome, but which have evolved as responses to different causes in different millipede taxa and therefore need to be examined on a case-to-case basis.


Assuntos
Migração Animal , Artrópodes/fisiologia , Animais , Artrópodes/parasitologia , Ecossistema , Feminino , Ilhas , Japão , Masculino , Filogenia , Rhabdiasoidea/isolamento & purificação , Rhabdiasoidea/fisiologia , Estações do Ano
5.
J Parasitol ; 95(2): 275-80, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18712948

RESUMO

We examined a population of northern leopard frogs to determine whether sex biases in investment in immunity, previously reported for this host species under controlled exposures to lung nematodes, is predictive of patterns of parasitism in nature. We examined Rhabdias ranae and Haematoloechus spp. infections in 74 breeding adult, 28 non-breeding adult, and 53 juvenile frogs. Contrary to our predictions, R. ranae prevalence and mean abundance were higher in breeding female frogs (prevalence: 39.4%, abundance: 3.05 +/- 0.85) than on breeding males (prevalence: 26.0%, abundance: 1.17 +/- 0.52), although no sex bias was observed among non-breeding adults or juvenile frogs. Female frogs also carried larger R. ranae worms, on average, than did males (females: 6407.38 microm +/- 153.80; males: 5198 microm +/- 131.09), regardless of age or breeding condition. We observed no sex-linked patterns of parasitism by Haematoloechus spp. worms in either adult or juvenile frogs. Alternative hypotheses, such as differences among sexes in the selection of thermal clines for hibernation, may explain the observed female bias in parasitism by nematode lungworms in nature and, thus, need to be considered.


Assuntos
Pneumopatias Parasitárias/veterinária , Rana pipiens/parasitologia , Rhabdiasoidea/fisiologia , Infecções por Rhabditida/veterinária , Trematódeos/fisiologia , Infecções por Trematódeos/veterinária , Fatores Etários , Análise de Variância , Animais , Cruzamento , Feminino , Interações Hospedeiro-Parasita , Pulmão/parasitologia , Pneumopatias Parasitárias/epidemiologia , Pneumopatias Parasitárias/parasitologia , Masculino , Ontário/epidemiologia , Prevalência , Rhabdiasoidea/anatomia & histologia , Infecções por Rhabditida/epidemiologia , Infecções por Rhabditida/parasitologia , Estações do Ano , Fatores Sexuais , Trematódeos/anatomia & histologia , Infecções por Trematódeos/epidemiologia , Infecções por Trematódeos/parasitologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA