RESUMO
Nematomorph parasites manipulate terrestrial arthropods to enter streams where the parasites reproduce. These manipulated arthropods become a substantial prey subsidy for stream salmonids, causing cross-ecosystem energy flow. Diverse nematomorph-arthropod associations underlie the energy flow, but it remains unknown whether they can mediate the magnitude and temporal attributes of the energy flow. Here, we investigated whether distinct phylogenetic groups of nematomorphs manipulate different arthropod hosts and mediate seasonal prey subsidy for stream salmonids. The results of our molecular-based diagnoses show that Gordionus and Gordius nematomorphs infected ground beetle and orthopteran hosts, respectively. The presumable ground beetle hosts subsidized salmonid individuals in spring, whereas the presumable orthopteran hosts did so in autumn. Maintaining the two distinct nematomorph-arthropod associations thus resulted in the parasite-mediated prey subsidy in both spring and autumn in the study streams. Manipulative parasites are common, and often associated with a range of host lineages, suggesting that similar effects of phylogenetic variation in host-parasite associations on energy flow might be widespread in nature.
Assuntos
Ecossistema , Interações Hospedeiro-Parasita , Estações do Ano , Animais , Salmonidae/parasitologia , Filogenia , Helmintos/fisiologia , Besouros/parasitologia , Besouros/fisiologia , RiosRESUMO
Among gastrointestinal nematodes, Haemonchus contortus (Rudolphi) Cobb (order Strongylidae; family Trichostrongylidae) is one of pathogenic and economic importance in domestic and wild ruminants, including the European bison, Bison bonasus Linnaeus (order Cetartiodactyla; family Bovidae); a species on the International Union for Conservation of Nature's Red List of Threatened Species. Carabus granulatus Linnaeus (order Coleoptera; family Carabidae) is one of the most prevalent species of ground beetle, inhabiting a wide range of terrestrial ecosystems in Poland. Twenty-six ground beetles of this species inhabiting the Bialowieza Primeval Forest in eastern Poland were screened for the presence of DNA of pathogenic gastrointestinal nematodes of ruminants. Extracted DNA was sequenced and compared to reference sequences. In six insects, the presence of H. contortus DNA was detected. The obtained nucleotide sequences were homologous to each other and to the majority of the published DNA sequences of H. contortus isolates. The sequences were also identical to a sequence of H. contortus isolated from European bison in Poland. The study provides the first molecular evidence of the presence of H. contortus DNA in C. granulatus. The finding suggests that ground beetles may play a role in the transmission dynamics of this parasite.
Assuntos
Besouros , Haemonchus , Animais , Besouros/parasitologia , Haemonchus/genética , Haemonchus/classificação , Polônia , DNA de Helmintos/análise , Análise de Sequência de DNA , Filogenia , Dados de Sequência Molecular , Sequência de Bases , BisonRESUMO
The Japanese sawyer beetle, Monochamus alternatus, is not only one of the most important wood boring pest itself, but also a major vector of the invasive pinewood nematode (PWN), which is the causal agent of the devastative pine wilt disease (PWD) and threats the global pine forest. Here, we present a near-complete genome of M. alternatus at the chromosome level. The assembled genome was 792.05 Mb with contig N50 length of 55.99 Mb, which is the largest N50 size among the sequenced Coleoptera insects currently. 99.57% of sequence was anchored onto ten pseudochromosomes (one X-chromosome and nine autosomes), and the final genome harbored only 13 gaps. BUSCO evaluation revealed the presence of 99.0% of complete core genes. Thus, our genome assembly represented the highest-contiguity genome assembly as well as high completeness in insects so far. We identified 20,471 protein-coding genes, of which 20,070 (98.04%) were functionally annotated. The genome assembly of M. alternatus provides a valuable resource for exploring the evolution of the symbiosis between PWN and the vector insects.
Assuntos
Besouros , Genoma de Inseto , Nematoides , Pinus , Animais , Besouros/genética , Besouros/parasitologia , Pinus/parasitologia , Madeira , Insetos Vetores/genética , Insetos Vetores/parasitologiaRESUMO
BACKGROUND: Agricultural landscapes provide resources for arthropod pests as well as their natural enemies. To develop integrated pest management (IPM) practices, it is important to understand how spatiotemporal location influences crop colonization and damage severity. We performed a 3-year (2016-2018) field experiment in winter oilseed rape (OSR, Brassica napus) fields in Estonia, where half of the fields were within 500 m of the location of the previous year's winter OSR field and half were outside this zone. We investigated how distance from the previous year's OSR crop influences the infestation and parasitism rates of two of its most important pests: the pollen beetle (Brassicogethes aeneus) and the cabbage seed weevil (Ceutorhynchus obstrictus). RESULTS: When the distance from the previous year's OSR crop was >500 m, we recorded significantly reduced pest pressure by both B. aeneus and C. obstrictus in the study fields. Biocontrol of both pests, provided by parasitic wasps, was high in each study year and commonly not affected by distance. Mean parasitism rates of B. aeneus were >31%, occasionally reaching >70%; for C. obstrictus, mean parasitism was >46%, reaching up to 79%, thereby providing effective biocontrol for both pest species. CONCLUSION: Spatiotemporal separation of OSR fields can reduce pest pressure without resulting in reduced parasitism of OSR pests. This supports a spatiotemporal field separation concept as an effective and sustainable technique for IPM in OSR. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
Assuntos
Artrópodes , Brassica napus , Besouros , Vespas , Gorgulhos , Animais , Besouros/parasitologiaRESUMO
Gregarine apicomplexans, a group of single celled organisms, inhabit the extracellular spaces of most invertebrate species. The nature of the gregarine-host interactions is not yet fully resolved, mutualistic, commensal and parasitic life forms have been recorded. In the extreme arid environment of the Atacama Desert, only a few groups of invertebrates hosting gregarines such as darkling beetles (Tenebrionidae) were able to adapt, providing an unparalleled opportunity to study co-evolutionary diversification. Here, we describe one novel gregarine genus comprising one species, Atacamagregarina paposa gen. et sp. nov., and a new species, Xiphocephalus ovatus sp. nov. (Apicomplexa: Eugregarinoridea, Stylocephalidae), found in the tenebrionid beetle genera Scotobius (Tenebrioninae, Scotobiini) and Psectrascelis intricaticollis ovata (Pimeliinae, Nycteliini), respectively. In the phylogenetic analysis based on SSU rDNA, Atacamgregarina paposa representing the new genus is basal, forming a separate clade with terrestrial gregarines specific for North American darkling beetles.
Assuntos
Apicomplexa , Besouros , Animais , Besouros/genética , Besouros/parasitologia , Filogenia , Evolução Biológica , Apicomplexa/genética , DNA Ribossômico/genéticaRESUMO
Some animals react to predation threats or other stressors by adopting a freezing posture in an attempt to avoid detection, and the duration of this behavior usually corresponds with individual personality, such that timid individuals freeze longer. Despite decades of research on this or related behaviors (thanatosis), never has the impact of parasitism been considered. Parasites could prolong the duration, if hosts are less motivated to move (i.e. lethargic), or they could reduce it, if hosts are motivated to forage more to compensate for energy drain. We examined this behavior within a natural beetle-nematode system, where hosts (horned passalus beetles, Odontotaenius disjunctus) are parasitized by a nematode, Chondronema passali. We exposed beetles (n = 238) to four stressors in our lab, including noise, vibration, light and inversion, and recorded how long they adopt a frozen stance. Afterward, we determined nematode burdens, which can range from dozens to hundreds of worms. Beetles tended to freeze for 20 seconds on average, with some variation between stressors. We detected no effect of beetle mass on the duration of freezing, and this behavior did not differ in beetles collected during the breeding or non-breeding season. There was a surprising sex-based difference in the impact of nematodes; unparasitized females remained frozen twice as long as unparasitized males, but for beetles with heavy nematode burdens, the opposite was true. From this we infer that heavily parasitized females are more bold, while males with heavy burdens would be more timid. The explanation for this finding remains elusive, though we can rule out many possibilities based on prior work on this host-parasite system.
Assuntos
Besouros , Nematoides , Parasitos , Animais , Feminino , Masculino , Besouros/parasitologia , Congelamento , Personalidade , Interações Hospedeiro-ParasitaRESUMO
Our understanding of environmental acquisition of microbes and migration-related alteration of microbiota across habitats has rapidly increased. However, in complex life cycles, such as for many parasites, exactly how these microbes are transmitted across multiple environments, such as hosts and habitats, is unknown. Pinewood nematode, the causal agent of the globally devastating pine wilt disease, provides an ideal model to study the role of microbiota in multispecies interactions because its successful host invasion depends on the interactions among its vector insects, pine hosts, and associated microbes. Here, we studied the role of bacterial and fungal communities involved in the nematode's life cycle across different micro- (pupal chamber, vector beetle, and dispersal nematodes) and macrohabitats (geographical locations). We identified the potential sources, selection processes, and keystone taxa involved in the host pine-nematode-vector beetle microbiota interactions. Nearly 50% of the microbiota in vector beetle tracheae and ~60% that of third-stage dispersal juveniles were derived from the host pine (pupal chambers), whereas 90% of bacteria of fourth-stage dispersal juveniles originated from vector beetle tracheae. Our results also suggest that vector beetles' tracheae selectively acquire some key taxa from the microbial community of the pupal chambers. These taxa will be then enriched in the dispersal nematodes traveling in the tracheae and hence likely transported to new host trees. Taken together, our findings contribute to the critical information toward a better understanding of the role of microbiota in pine wilt disease, therefore aiding the knowledge for the development of future biological control agents. IMPORTANCE Our understanding of animal microbiota acquisition and dispersal-mediated variation has rapidly increased. In this study, using the model of host pine-pinewood nematode-vector beetle (Monochamus sp.) complex, we disentangled the routes of microbial community assembly and transmission mechanisms among these different participants responsible for highly destructive pine wilt disease. We provide evidence that the microhabitat is the driving force shaping the microbial community of these participants. The microbiota of third-stage dispersal juveniles (LIII) of the nematodes collected around pupal chambers and of vector beetles were mainly derived from the host pine (pupal chambers), whereas the vector-entering fourth-stage dispersal juveniles (LIV) of the nematodes had the simplest microbiota community, not influencing vector's microbiota. These findings enhanced our understanding of the variation in the microbiota of plants and animals and shed light on microbiota acquisition in complex life cycles.
Assuntos
Besouros , Microbiota , Nematoides , Pinus , Animais , Bactérias/genética , Besouros/microbiologia , Besouros/parasitologia , Humanos , Estágios do Ciclo de Vida , Nematoides/microbiologia , Pinus/parasitologia , PrevalênciaRESUMO
Emerald ash borer (Agrilus planipennis Fairmaire (Coleoptera: Buprestidae)), an invasive phloem-feeding beetle native to Asia, has devastated North American ash forests since its detection in Michigan, United States in 2002. As the emerald ash borer has continued to spread, the potential for successful long-term management hinges upon the release, establishment, and spread of introduced larval and egg parasitoids for biological control. Here, we focus on the establishment and evidence for spatial spread of introduced larval parasitoid, Spathius agrili Yang and Spathius galinae Belokobylskij & Strazanac (Hymenoptera: Braconidae) in the state of Maryland. To assess each species, we analyzed historical release and recovery data and resampled previous release sites and nonrelease sites for establishment. We found little evidence of establishment or spread for S. agrili, despite a comparatively large number of release locations, events, and individuals. By contrast, despite much lower propagule pressure and shorter history of releases, we detected multiple established populations of S. galinae at release sites and at sites up to 90 km from the nearest release point approximately 3 yr after its most current release. Our findings show that S. galinae has established and spread rapidly following field releases whereas its congener, S. agrili has not. Although it may still be too early to evaluate the level of population control and ash protection afforded by S. galinae, these findings indicate the need for continued investment in S. galinae for emerald ash borer classical biological control efforts.
Assuntos
Agentes de Controle Biológico , Besouros , Fraxinus , Vespas , Animais , Besouros/parasitologia , Espécies Introduzidas , Larva , MarylandRESUMO
In this study, we conducted a summer sampling of carabid beetles in eastern Australia to identify their associated parasitic mites. Here, we describe three new species of the genus Eutarsopolipus from under the elytra (forewings) of three native carabid species (Coleoptera: Carabidae): Eutarsopolipus paryavae n. sp. (pterostichi group) from Geoscaptus laevissimus Chaudoir; Eutarsopolipus pulcher n. sp. (leytei group) from Gnathaphanus pulcher (Dejean); and Eutarsopolipus chlaenii n. sp. (myzus group) from Chlaenius flaviguttatus Macleay. We further provide an identification key of the world species of pterostichi and leytei species groups as well as closely related species of the myzus group possessing similar characters including short cheliceral stylets. The significant diversity of Eutarsopolipus recovered here suggests that the current knowledge about Australian podapolipid mites (specially Eutarsopolipus) is still in its infancy and deserves further study.
TITLE: Vivre à l'abri sous les élytres : trois nouvelles espèces d'Eutarsopolipus (Acari, Heterostigmatina, Podapolipidae) parasitant des carabes australiens. ABSTRACT: Dans cette étude, nous avons effectué un échantillonnage estival de carabes dans l'est de l'Australie pour identifier leurs acariens parasites associés. Nous décrivons trois nouvelles espèces du genre Eutarsopolipus sous les élytres (ailes antérieures) de trois espèces de carabes indigènes (Coleoptera : Carabidae) : Eutarsopolipus paryavae n. sp. (groupe pterostichi) de Geoscaptus laevissimus Chaudoir, Eutarsopolipus pulcher n. sp. (groupe leytei) de Gnathaphanus pulcher (Dejean) et Eutarsopolipus chlaenii n. sp. (groupe myzus) de Chlaenius flaviguttatus Macleay. Nous fournissons en outre une clé d'identification des espèces mondiales des groupes d'espèces pterostichi et leytei ainsi que des espèces étroitement apparentées du groupe myzus possédant des caractères similaires, y compris des stylets chélicéraux courts. La diversité importante des Eutarsopolipus collectés ici suggère que les connaissances actuelles sur les acariens podapolipidés australiens (en particulier Eutarsopolipus) en sont encore à leurs balbutiements et méritent une étude plus approfondie.
Assuntos
Besouros , Ácaros , Animais , Austrália , Besouros/parasitologia , Ácaros/patogenicidadeRESUMO
Eutarsopolipus (Acari: Podapolipidae) is a large genus of mites parasitic in the subelytral space of carabid beetles. Herein, I explore the species radiations of Eutarsopolipus on the pterostichine genera Castelnaudia and Notonomus found in the rainforests of eastern Australia. Castelnaudia has an extraordinary radiation of podapolipid mite species, with most beetle species carrying multiple species of mites unique to each host. In contrast, each Notonomus species had just one species of Eutarsopolipus (with the exception of a single male mite of another species), and in four of the five host species examined, the single mite species could not be distinguished from each other. The host beetles and their new mite species are: Castelnaudia cordata with E. hebronae sp. nov., E. osculum sp. nov. and E. umbonatus sp. nov.; Castelnaudia eungella with E. savatus sp. nov.; Castelnaudia marginifera with E. labiatus sp. nov.; Castelnaudia mixta with E. mixtus sp. nov.; Castelnaudia porphyriaca with E. basiatus sp. nov., E. despoticus sp. nov. and E. teuceri sp. nov.; Castelnaudia septemcostata with E. nahmani sp. nov. and E. raveni sp. nov.; Castelnaudia setosiceps with E. hadros sp. nov.; Notonomus aurifer, N. dimorphicus, N. flos and N. spurgeoni with E. janus sp. nov.; and Notonomus transitus with E. biuncatus sp. nov. All the described species from Castelnaudia were from the ochoai species group, and the species on Notonomus were from the leytei species group. Ten additional undescribed species were also found on these hosts, all in numbers insufficient for description: nine from Castelnaudia (ochoai and pterostichi species groups) and one from Notonomus (undetermined species group). Synhospitality was common on Castelnaudia, with four species of Eutarsopolipus on C. cordata, C. eungella, C. porphyriaca and three on C. septemcostata. Co-infestation was also common, with one-third of infested beetles hosting two or more species of Eutarsopolipus. I speculate that the greater longevity and slower speciation rates of Castelnaudia have permitted more successful host-switching and speciation of its parasites.
Assuntos
Besouros/parasitologia , Ácaros/classificação , Animais , Austrália , Especificidade de Hospedeiro , Masculino , Floresta ÚmidaRESUMO
Developmental and behavioral plasticity allow animals to prioritize alternative genetic programs during fluctuating environments. Behavioral remodeling may be acute in animals that interact with host organisms, since reproductive adults and the developmentally arrested larvae often have different ethological needs for chemical stimuli. To understand the genes that coordinate the development and host-seeking behavior, we used the entomophilic nematode Pristionchus pacificus to characterize dauer-constitutive mutants (Daf-c) that inappropriately enter developmental diapause to become dauer larvae. We found two Daf-c loci with dauer-constitutive and cuticle exsheathment phenotypes that can be rescued by the feeding of Δ7-dafachronic acid, and that are dependent on the conserved canonical steroid hormone receptor Ppa-DAF-12. Specifically at one locus, deletions in the sole hydroxysteroid dehydrogenase (HSD) in P. pacificus resulted in Daf-c phenotypes. Ppa-hsd-2 is expressed in the canal-associated neurons (CANs) and excretory cells whose homologous cells in Caenorhabditis elegans are not known to be involved in the dauer decision. While in wildtype only dauer larvae are attracted to host odors, hsd-2 mutant adults show enhanced attraction to the host beetle pheromone, along with ectopic activation of a marker for putative olfactory neurons, Ppa-odr-3. Surprisingly, this enhanced odor attraction acts independently of the Δ7-DA/DAF-12 module, suggesting that Ppa-HSD-2 may be responsible for several steroid hormone products involved in coordinating the dauer decision and host-seeking behavior in P. pacificus.
Assuntos
Diapausa/genética , Regulação da Expressão Gênica no Desenvolvimento , Comportamento de Busca por Hospedeiro , Rabditídios/crescimento & desenvolvimento , Animais , Colestenos/metabolismo , Besouros/metabolismo , Besouros/parasitologia , Loci Gênicos , Proteínas de Helminto/genética , Proteínas de Helminto/metabolismo , Larva , Redes e Vias Metabólicas/genética , Mutação , Neurônios/metabolismo , Odorantes , Feromônios/metabolismo , Receptores de Esteroides/genética , Receptores de Esteroides/metabolismo , Rabditídios/genética , Olfato/genéticaRESUMO
García Coy (1994) described the hystrignathid nematode Longior alius García Coy, 1994 parasitizing the passalid beetle Antillanax pertyi (Kaup, 1869) from Guantánamo province, Eastern Cuba. Morffe García (2011) continued the studies on Cuban Longior and described L. longior Morffe García, 2011. Morffe et al. (2018) redescribed L. longior with the aid of SEM and molecular techniques. In their research the authors studied Longior individuals from the same host species and a locality close to the type locality of L. alius and compared their morphology, measurements and DNA markers with other material of L. longior. As a result of this analysis Morffe et al. (2018) concluded that L. alius and L. longior are conspecific and proposed L. alius as a synonym of L. longior.
Assuntos
Besouros , Oxyurida , Animais , Besouros/parasitologia , Cuba , Genes de Helmintos/genética , Microscopia Eletrônica de Varredura , Oxyurida/classificação , Oxyurida/genética , Oxyurida/ultraestrutura , Especificidade da EspécieRESUMO
In host-parasitoid interactions, antagonistic relationship drives parasitoids to vary in virulence in facing different hosts, which makes these systems excellent models for stress-induced evolutionary studies. Venom compositions varied between two strains of Tetrastichus brontispae, Tb-Bl and Tb-On. Tb-Bl targets Brontispa longissima pupae as hosts, and Tb-On is a sub-population of Tb-Bl, which has been experimentally adapted to a new host, Octodonta nipae. Aiming to examine variation in parasitoid virulence of the two strains toward two hosts, we used reciprocal injection experiments to compare effect of venom/ovarian fluids from the two strains on cytotoxicity, inhibition of immunity and fat body lysis of the two hosts. We found that Tb-Onvenom was more virulent towards plasmatocyte spreading, granulocyte function and phenoloxidase activity than Tb-Blvenom. Tb-Blovary was able to suppress encapsulation and phagocytosis in both hosts; however, Tb-Onovary inhibition targeted only B. longissima. Our data suggest that the venom undergoes rapid evolution when facing different hosts, and that the wasp has good evolutionary plasticity.
Assuntos
Besouros/parasitologia , Especificidade de Hospedeiro/genética , Interações Hospedeiro-Parasita/fisiologia , Animais , Evolução Molecular , Himenópteros/fisiologia , Fagocitose/fisiologia , Pupa/parasitologia , Virulência , Vespas/fisiologiaRESUMO
The peach bark beetle (Phloeotribus liminaris Harris, PBB) affects the health, quality, and value of black cherry (Prunus serotina Ehrh.) within the Central Hardwoods Forest Region of North America. When colonized by adult beetles, black cherry trees produce a defensive exudate, or 'gum', staining the wood and decreasing its value up to 90%. Current management tactics are inadequate to avoid extensive damage to most veneer-sized black cherry in the region. We test the hypothesis that PBB colonization behavior is chemically-mediated and determine the extent to which PBB is attracted to compounds associated with wounded or PBB-infested cherry wood. Through olfactometer and field bioassays, we determined that adult PBB were attracted to cherry branches infested with female beetles. We then used dynamic headspace sampling to collect volatiles associated with wounded and infested bolts of black cherry. The volatile benzaldehyde dominated these collections and was more abundant in aerations of female-infested bolts than other odor sources. In subsequent field bioassays, we evaluated the bioactivity of benzaldehyde, as well as α-longipinene, in combination with several chemical carriers. Traps baited with benzaldehyde captured more PBB than all other treatments, irrespective of other lure components. Moreover, PBB were not attracted to traps baited solely with ethanol, a common attractant for bark beetles that colonize hardwood trees. This is the first report of benzaldehyde as an attractant for a species of bark beetle and could aid in developing semiochemical-based management tactics for this important pest.
Assuntos
Besouros/parasitologia , Controle de Insetos/métodos , Odorantes/análise , Prunus avium/química , Prunus avium/metabolismo , Compostos Orgânicos Voláteis/análise , Animais , Comportamento Animal , Benzaldeídos/metabolismo , Etanol/química , Feminino , Cromatografia Gasosa-Espectrometria de Massas , América do Norte , Olfatometria , Feromônios/química , Feromônios/metabolismo , Sesquiterpenos/análise , Sesquiterpenos/metabolismo , Compostos Orgânicos Voláteis/metabolismoRESUMO
Longhorned beetles (Coleoptera: Cerambycidae) include many species that are among the most damaging pests of managed and natural forest ecosystems worldwide. Many species of cerambycids use volatile chemical signals (i.e., pheromones) to locate mates. Pheromones are often used by natural enemies, including parasitoids, to locate hosts and therefore can be useful tools for identifying host-parasitoid relationships. In two field experiments, we baited linear transects of sticky traps with pheromones of cerambycid beetles in the subfamily Cerambycinae. Enantiomeric mixtures of four linear alkanes or four linear alkanes and a ketol were tested separately to evaluate their attractiveness to hymenopteran parasitoids. We hypothesized that parasitoids would be attracted to these pheromones. Significant treatment effects were found for 10 species of parasitoids. Notably, Wroughtonia ligator (Say) (Hymenoptera: Braconidae) was attracted to syn-hexanediols, the pheromone constituents of its host, Neoclytus acuminatus acuminatus (F.) (Coleoptera: Cerambycidae). Location and time of sampling also significantly affected responses for multiple species of parasitoids. These findings contribute to the basic understanding of cues that parasitoids use to locate hosts and suggest that pheromones can be used to hypothesize host relationships between some species of cerambycids and their parasitoids. Future work should evaluate response by known species of parasitoids to the complete blends of pheromones used by the cerambycids they attack, as well as other odors that are associated with host trees of cerambycids.
Assuntos
Besouros/parasitologia , Atrativos Sexuais/fisiologia , Vespas/fisiologia , Animais , Besouros/fisiologia , Controle Biológico de VetoresRESUMO
Aethina tumida Murray is currently a worldwide emergent pest of Apis mellifera L. hives. Although the damaging effect on the colony stores and brood is well known, the possible role of these beetles as a disease carrier is not clear. This is the first report of DNA presence of the trypanosome honeybee parasite Lotmaria passim and Crithidia bombi, and the Apis mellifera filamentous virus (AmFV) in A. tumida. Further studies will be needed to determine if A. tumida is indeed a mechanical or biological vector of these pathogens.
Assuntos
Abelhas , Besouros , Trypanosoma/isolamento & purificação , Animais , Besouros/parasitologiaRESUMO
Symbiotic microbes play a crucial role in regulating parasite-host interactions; however, the role of bacterial associates in parasite-host interactions requires elucidation. In this study, we showed that, instead of introducing numerous symbiotic bacteria, dispersal of 4th-stage juvenile (JIV ) pinewood nematodes (PWNs), Bursaphelenchus xylophilus, only introduced few bacteria to its vector beetle, Monochamus alternatus (Ma). JIV showed weak binding ability to five dominant bacteria species isolated from the beetles' pupal chamber. This was especially the case for binding to the opportunistic pathogenic species Serratia marcescens; the nematodes' bacteria binding ability at this critical stage when it infiltrates Ma for dispersal was much weaker compared with Caenorhabditis elegans, Diplogasteroides asiaticus, and propagative-stage PWN. The associated bacterium S. marcescens, which was isolated from the beetles' pupal chambers, was unfavorable to Ma, because it caused a higher mortality rate upon injection into tracheae. In addition, S. marcescens in the tracheae caused more immune effector disorders compared with PWN alone. Ma_Galectin2 (MaGal2), a pattern-recognition receptor, was up-regulated following PWN loading. Recombinant MaGal2 protein formed aggregates with five dominant associated bacteria in vitro. Moreover, MaGal2 knockdown beetles had up-regulated prophenoloxidase gene expression, increased phenoloxidase activity, and decreased PWN loading. Our study revealed a previously unknown strategy for immune evasion of this plant pathogen inside its vector, and provides novel insights into the role of bacteria in parasite-host interactions.
Assuntos
Besouros , Galectinas/metabolismo , Evasão da Resposta Imune , Rabditídios/patogenicidade , Animais , Bactérias , Besouros/imunologia , Besouros/parasitologia , Vetores de Doenças , Galectinas/genética , Genes de Insetos , Interações Hospedeiro-Parasita , Imunidade , Monofenol Mono-Oxigenase/metabolismo , Doenças das Plantas/parasitologia , Receptores de Reconhecimento de Padrão/genética , Receptores de Reconhecimento de Padrão/metabolismo , Rabditídios/microbiologia , SimbioseRESUMO
Leptus (Leptus) grancanaricus n. sp. and L. (L.) machadoi n. sp. are described from Gran Canaria and Fuerteventura (Canary Islands). They were collected from new hosts for the genus Leptus: Herpisticus guanarteme Machado and Laparocerus maxorata Machado (Coleoptera: Curculionidae). New metrical data for Leptus (Leptus) andae, L. (L.) akkus, L. (L.) hammameticus, L. (L.) horiacus and L. (L.) tammuzi based on examination on the type-material are provided.
Assuntos
Besouros/parasitologia , Ácaros/anatomia & histologia , Ácaros/classificação , Animais , Espanha , Especificidade da EspécieRESUMO
The Japanese pine sawyer, Monochamus alternatus Hope (Coleoptera: Cerambycidae), transfers the pine wood nematode, Bursaphelenchus xylophilus (Steiner and Buhrer) that causes pine wilt disease (PWD), especially in Asian countries. The key for the control of PWD is primarily focused on vector management. Thus, understanding the exact life history of M. alternatus is required. Since the late 1980s, the life cycle of M. alternatus has been accepted under the assumption that the final larvae pass four instars in the field. This study is revising the previous error for the life cycle hypothesis of M. alternatus by finding various instar pathways, which pathway is defined as the number of instars that larvae pass through prior to pupation. We confirm experimentally that the overwintered fourth or fifth instar larvae directly pupate to emerge as adults, indicating the presence of four and five instar pathways, respectively. The selection of instar pathway might be determined primarily by habitat temperature. This information will be useful to explain the variation of life history in M. alternatus populations worldwide based on the thermal environments, and also can be served to predict the northern distribution limit by applying the threshold degree-days for the completion of four instar pathway.
Assuntos
Besouros/parasitologia , Insetos Vetores/parasitologia , Larva/patogenicidade , Estágios do Ciclo de Vida , Nematoides/patogenicidade , Pinus/parasitologia , Doenças das Plantas/parasitologia , Animais , Ásia , Ecossistema , Meio Ambiente , TemperaturaRESUMO
Bess beetles (Passalidae) display important roles in forestall ecosystems, particularly in energy extraction from dead wood. These organisms maintain complex biological interactions with their gut symbiotic communities, including bacteria, protists, and metazoans. Very little is known about symbionts since most of the species of Passalidae haven't been studied from a parasitological point of view. Here we describe a new genus and 2 new species of nematodes of the family Hystrignathidae associated with 2 beetle species of the tribe Proculini collected in the State of Oaxaca, Mexico. Tuhmai garciaprietoi n. gen., n. sp., found in Vindex agnoscendus is characterized by the presence of an unarmed cervical cuticle, a subcylindrical procorpus and a conspicuous isthmus, a monodelphic-prodelphic reproductive system, and a short subulate tail. Urbanonema osorioi n. sp., found in Verres hageni mainly differs from other species of Urbanonema by the number and disposition of cervical spines, as well as by a subulate tail. For each new taxon, we describe the external and internal morphology, and we generated molecular data (nuclear ribosomal DNA) to place the new taxa in a phylogenetic context.