Biological characteristics of Trissolcus urichi (Crawford) (Hymenoptera: Scelionidae) on Euschistus heros (Fabricius) and Dichelops melacanthus (Dallas) (Hemiptera: Pentatomidae) Eggs.

Species of the genus Trissolcus are effective as egg parasitoids of Euschistus heros and can potentially be used in a multispecies pest management approach. However, in order to successfully use those biocontrol agents in the field, previous detailed knowledge about their life history are necessary. Therefore, we evaluate some biological characteristics of Trissolcus urichi on Euschistus heros and Dichelops melacanthus eggs. Three independent experiments were performed: (1) T. urichi host preference between E. heros and D. melacanthus eggs. (2) T. urichi eggs-adult period (days), number of parasitized eggs in 24 h, emergence rate (%) and sex ratio of the parasitoid in E. heros and D. melacanthus eggs. (3) Morphometric characteristics of T. urichi grown on E. heros and D. melacanthus eggs. Trissolcus urichi preferred to parasitize E. heros eggs, exhibiting a higher number of parasitized eggs, higher rate of emergence (%) and faster development, as well as producing progeny of larger size than the parasitoids emerged from eggs of D. melacanthus in relation to body length, wing length and width. Thus, it can be concluded that T. urichi had better performance on E. heros eggs, although the parasitoid had also acceptable parasitism capacity and development in D. melacanthus eggs.

Low host specificity and lack of parasite avoidance by immature ticks in Brazilian birds.

Ticks are ectoparasites that feed on blood of a broad taxonomic range of terrestrial and flying vertebrates and are distributed across a wide range of environmental conditions. Here, we explore the biotic and abiotic factors on infestation probability of ticks of the genus Amblyomma and assess the degree of host specificity based on analysis of 1028 birds surveyed across Brazil. We show that tick infestation rates exhibited considerable variation across the 235 avian species analyzed and that the probability of an individual bird being parasitized by immature ticks (larvae and nymphs) increased with annual precipitation. Host phylogeny and two host ecological traits known to promote tick exposure (body mass and foraging behavior) did not predict infestation probability. Moreover, immature ticks displayed a low degree of host specificity at the family level. Lastly, tick occurrence in birds carrying infection with avian malaria and related parasites did not differ from those free of these haemosporidian parasites, indicating a lack of parasite avoidance by immature ticks. Our findings demonstrate that tick occurrence in birds across Brazilian biomes responds to environmental factors rather than ecological and evolutionary host attributes.

Molecular genotyping of Blastocystis spp. in wild mammals from Mexico.

Blastocystis spp. are common intestinal parasites found worldwide in humans and a wide range of animals. They exhibit extensive genetic diversity; currently, 17 subtypes (STs) and some groups called non-mammalian and avian STs (NMASTs) have been proposed. In addition, a large variety of animals have been reported as hosts of the parasite, and new hosts and STs are still being described. In this study, Blastocystis infection of wild animals in two sylvatic areas of Mexico was surveyed. Of one hundred twenty-four fecal samples, six were positive for Blastocystis: specifically, one sample from an opossum, one sample from a bat, and four samples from different species of rodents. ST4, ST17, and nucleotide sequences similar to Blastocystis lapemi were identified based on SSU rDNA sequences. To our knowledge, this is the first report to investigate species poorly or not previously evaluated for Blastocystis infection. Mammals having different niches and geographical distribution were infected with similar genetic type of Blastocystis, so that we suggest that local water or food sources could play an important role in Blastocystis transmission and ST maintenance in wild animals. Additionally, there are STs with scarce genetic variation, suggesting that they could be highly adapted to their hosts. These data contribute to our understanding of the host range and genetic diversity of Blastocystis.

Host ecology moderates the specialization of Neotropical bat-fly interaction networks.

The transmission of diseases through parasites is a key mechanism in the regulation of plant and animal populations in ecosystems. Therefore, it is necessary to investigate the relative effect of the variables that can shape the specificity of host-parasite interactions. Previous studies have found that specialization of antagonistic interactions between fly ectoparasites and bats changes according to forest type, host richness, and roosting ecology of bats. In this study, we tested these hypotheses using data from 48 bat communities. In general, our results support previous findings that bat-fly interactions are specialized, resulting in lower niche overlap among bat flies species. In addition, we found that the specificity of bat-fly interactions is lower in tropical mountain forests and is positively related with the richness of bat host species of each study site. Finally, there was a higher bat flies niche overlap in smaller bat-fly interaction networks recorded in bat roosts in caves. We conclude that the roosting ecology of bats could be a key factor to understand the mechanisms related to the horizontal transmission of ectoparasitic flies among bats.

Macroscale analysis of mistletoe host ranges in the Andean-Patagonian forest.

The number of host species infected by a mistletoe (host range) is critical in that it influences prevalence, virulence and overall distribution of the parasite; however, macroecological analyses of this life history feature are lacking for many regions. The Andean-Patagonian forest, found along the southern Andes from 35 °S to Tierra del Fuego at 55 °S, contains 12 mistletoe species in three families (Loranthaceae, Misodendraceae and Santalaceae). By tabulating herbarium records, the host ranges and geographical distributions of these mistletoes were explored. Our results show that these parasites occur on 43 plant species in 24 families but with varying degrees of specificity. All Misodendrum species and Desmaria mutabilis (Loranthaceae) are specialists that use Nothofagus as their primary hosts. Tristerix and Notanthera (Loranthaceae) and Antidaphne and Lepidoceras (Santalaceae) are generalists parasitizing more than six host species from several genera and families. Although many of the mistletoe species are sympatric, there is low overlap in host use. Our data show that in the southern South American bioregion, generalist mistletoes have smaller geographic ranges than specialists. This contrast with a previous hypothesis that predicted mistletoes with large geographic ranges would also have large host ranges, and conversely, less diverse regions would have more specialised mistletoes.

Changing interactions among persistent species as the major driver of seasonal turnover in plant-caterpillar interactions.

ß diversity of herbivorous insects in the tropics is usually very high, and there is often strong dissimilarity in herbivore species composition across different spatial scales and different abiotic gradients. Similarly, turnover is high for trophic interactions between herbivorous insects and their host plants. Two factors have been proposed to explain temporal or spatial differences in trophic interactions: changes in species composition and temporal changes in the behavior of shared species. The goal of this study was to evaluate determinants of high ß diversity of trophic interactions between lepidopteran caterpillars and their host plants across dry and rainy seasons and their transitions. Over the course of a year, interaction diversity data were collected from 275 temporary plots in Cerrado vegetation, comprising 257 species of caterpillars, 137 species of host plants and 503 different trophic interactions. All these diversity parameters varied across seasons. Species assemblages of caterpillars and plants were different among the four seasons, and there was a high turnover of interactions between the seasons. The high temporal ß diversity of trophic interactions was mostly due to interaction rewiring between co-occurring species, as opposed to changes in species composition over time.

Effects of Host Interspecific Interaction in the Maculinea-Myrmica Parasite-Host System.

A model of interspecific host competition in a system with one parasite (butterfly-Maculinea) and multiple potential hosts (ants-Myrmica) is presented. Results indicate that host interspecific competition increases the occurrence of multiple host behaviour in Maculinea natural populations but decreases the ability of the parasite populations to adapt to the most abundant host species. These qualitative predictions were compared with data on host specificity, with good agreement. Analysis of the data also indicates that Maculinea teleius and Maculinea arion respond differently to changes in relative host abundances. Maculinea teleius shows a larger fraction of sites where it displays multiple host behaviour and a larger fraction of sites where the niches of the hosts overlap. In some instances, Maculinea teleius is adapted to Myrmica hosts that are present in lower frequencies. Maculinea arion is locally more host-specific and occurs at sites where host interspecific competition is unlikely and is more frequently adapted to the most abundant host species.

Host specificity in a diverse Neotropical tick community: an assessment using quantitative network analysis and host phylogeny.

BACKGROUND: Host specificity is a fundamental determinant of tick population and pathogen transmission dynamics, and therefore has important implications for human health. Tick host specificity is expected to be particularly high in the tropics, where communities of ticks, hosts and pathogens are most diverse. Yet the degree to which tropical tick species are host-specific remains poorly understood. Combining new field data with published records, we assessed the specificity of tick-host associations in Panama, a diverse Neotropical region. METHODS: The resulting dataset includes 5,298 adult ticks belonging to 41 species of eight genera that were directly collected from 68 vertebrate host species of 17 orders. We considered three important aspects of tick host specificity: (i) the relative ecological importance of each host species (structural specificity); (ii) relatedness among host species (phylogenetic specificity); and (iii) spatial scale-dependence of tick-host relationships (geographical specificity). Applying quantitative network analyses and phylogenetic tools with null model comparisons, we assessed the structural and phylogenetic specificity across three spatial scales, ranging from central Panama to countrywide. Further, we tested whether species-rich tick genera parasitized a wider variety of hosts than species-poor genera, as expected when ticks specialize on different host species. RESULTS: Most tick species showed high structural and/or phylogenetic specificity in the adult stage. However, after correcting for sampling effort, we found little support for geographical specificity. Across the three scales, adult ticks tended to be specific to a limited number of host species that were phylogenetically closely related. These host species in turn, were parasitized by tick species from distinct genera, suggesting switching among distantly related hosts is common at evolutionary timescales. Further, there was a strong positive relationship between the taxonomic richness of the tick genera and that of their hosts, consistent with distinct tick species being relatively specific to different host species. CONCLUSIONS: Our results indicate that in the adult stage, most ticks in the diverse Neotropical community studied are host specialists. This contrasts with earlier assessments, but agrees with findings from other host-parasite systems. High host specificity in adult ticks implies high susceptibility to local tick-host co-extirpation, limited ability to colonize new habitats and limited potential for interspecific pathogen transmission.

New host, geographic records, and histopathologic studies of Angiostrongylus spp (Nematoda: Angiostrongylidae) in rodents from Argentina with updated summary of records from rodent hosts and host specificity assessment.

To date, 21 species of the genus Angiostrongylus (Nematoda: Angiostrongylidae) have been reported around the world, 15 of which are parasites of rodents. In this study, new host, geographic records, and histopathologic studies of Angiostrongylus spp in sigmodontine rodents from Argentina, with an updated summary of records from rodent hosts and host specificity assessment, are provided. Records of Angiostrongylus costaricensis from Akodon montensis and Angiostrongylus morerai from six new hosts and geographical localities in Argentina are reported. The gross and histopathologic changes in the lungs of the host species due to angiostrongylosis are described. Published records of the genus Angiostrongylus from rodents and patterns of host specificity are presented. Individual Angiostrongylus species parasitise between one-19 different host species. The most frequent values of the specificity index (STD) were between 1-5.97. The elevated number of host species (n = 7) of A. morerai with a STD = 1.86 is a reflection of multiple systematic studies of parasites from sigmodontine rodents in the area of Cuenca del Plata, Argentina, showing that an increase in sampling effort can result in new findings. The combination of low host specificity and a wide geographic distribution of Angiostrongylus spp indicates a troubling epidemiological scenario although, as yet, no human cases have been reported.

New host, geographic records, and histopathologic studies ofAngiostrongylus spp (Nematoda: Angiostrongylidae) in rodents from Argentina with updated summary of records from rodent hosts and host specificity assessment

To date, 21 species of the genus Angiostrongylus (Nematoda: Angiostrongylidae) have been reported around the world, 15 of which are parasites of rodents. In this study, new host, geographic records, and histopathologic studies of Angiostrongylus spp in sigmodontine rodents from Argentina, with an updated summary of records from rodent hosts and host specificity assessment, are provided. Records of Angiostrongylus costaricensis from Akodon montensis andAngiostrongylus morerai from six new hosts and geographical localities in Argentina are reported. The gross and histopathologic changes in the lungs of the host species due to angiostrongylosis are described. Published records of the genus Angiostrongylus from rodents and patterns of host specificity are presented. Individual Angiostrongylusspecies parasitise between one-19 different host species. The most frequent values of the specificity index (STD) were between 1-5.97. The elevated number of host species (n = 7) of A. morerai with a STD = 1.86 is a reflection of multiple systematic studies of parasites from sigmodontine rodents in the area of Cuenca del Plata, Argentina, showing that an increase in sampling effort can result in new findings. The combination of low host specificity and a wide geographic distribution of Angiostrongylus spp indicates a troubling epidemiological scenario although, as yet, no human cases have been reported.

The tidepool shrimp, Palaemon ritteri Holmes, constitutes a novel host to the white spot syndrome virus.

The white spot syndrome virus (WSSV) is a lethal and contagious pathogen for penaeid shrimp and a growing number of other crustacean species. To date, there are no effective prophylactic or therapeutic treatments commercially available to interfere with the occurrence and spread of the disease. In addition, the significance of alternative vectors on the dispersal of this disease has been largely ignored and therefore the ecological dynamics of the WSSV is still poorly understood and difficult to ascertain. Thus, an important issue that should be considered in sanitary programmes and management strategies is the identification of species susceptible to infection by WSSV. The results obtained provide the first direct evidence of ongoing WSSV replication in experimentally infected specimens of the tidepool shrimp Palaemon ritteri. Viral replication was detected using a validated set of primers for the amplification by RT-PCR of a 141 bp fragment of the transcript encoding the viral protein VP28. It is therefore conceivable that this shrimp may play a significant role in the dispersal of WSSV.

Comparing feeding and reproductive parameters of Amblyomma parvum tick populations (Acari: Ixodidae) from Brazil and Argentina on various host species.

Amblyomma parvum is a Neotropical tick that is widely spread and a potential vector of pathogens, including Rickettsiae. Genetic differences are remarkable between A. parvum populations from Brazil and Argentina. In this work, feeding and reproduction parameters of A. parvum ticks from these two populations were compared on some key host species to evaluate possible differences in host suitability between them. On the whole parameters of these tick populations were similar when fed on the same host and varied similarly on different host species. Still, bovines were more suitable host for Argentinian larvae than for Brazilian cohorts. It was observed that guinea pigs were the best host A. parvum immatures from both origins, as depicted from higher recovery rate of larvae and heavier engorged nymph weights. Canids and bovids were host species most suitable to adults of both tick populations as shown by the highest number of larvae produced by adult females that engorged on these hosts. Taken together, results showed that in spite of the genetic divergence, A. parvum from Argentina and Brazil have similar biological performance on various host species.

Two new species of Cotingacola Carriker, Phthiraptera: Ischnocera: Philopteridae) from Amazonian Brazil, with comments on host-specificity.

This paper describes two new species of Cotingacola Carriker, 1956, C. lutzae n. sp. and C. engeli n. sp., from the cinereous mourner Laniocera hypopyrra (Vieillot) and black-necked red cotinga Phoenicircus nigricollis Swainson (Aves: Passeriformes: Cotingidae), respectively. These species are fully illustrated and compared with their morphologically closest relatives. With the addition of these two new species, this Neotropical chewing louse genus now includes ten species. We also present records from Brazil for two previously described species, C. stotzi Clayton & Price, 1998 and C. parmipapillae Carriker, 1956. The re-examination of a specimen identified as 'Cotingacola sp.' in a recent phylogenetic study confirmed that it is C. parmipapillae and that Querula purpurata (Statius Müller) regularly hosts two Cotingacola species, which means that at least three cotingid hosts carry more than one species of Cotingacola. We comment on the variability in the host-specificity of Cotingacola species.

Record of Myiasis by Cuterebra apicalis in Domestic Dog in the Central Region of Brazil / Registro de miíase por Registro de miíase por Cuterebra apicalis em cão doméstico na região Central do Brasil

Background: Cuterebrosis is a furuncular myiasis caused by a dipterous from the genus Cuterebra. These flies are highly species-specific in relation to their hosts, being mostly common to rodents, lagomorphs and marsupials, with the development of a large subcutaneous furuncle as the main clinical manifestation. The most important microscopic alterations are the invasion of the damaged area by neutrophils, lymphocytes, macrophages, eosinophils and mast cells and the proliferation of fibroblasts and endothelial cells. However, the Cuterebrosis can occur in domestic animals, causing the formation of an atypical parasitic cycle, with the development of significant and severe clinical signs due to the erroneous migration of larvae, a situation not observed in typical hosts. Neuritis has been verified in cats due to the migration triggered by the larvae, causing irreversible damage to the central nervous system. In Brazil no reports of cases of myiasis in dogs and cats have been reported for any species of Neotropical Cuterebra. One of the species most commonly found in studies parasitizing mammals in the Midwest is Cuterebra apicalis. However, this Diptera has only been found parasitizing marsupials Didelphidae rodents and rodent Cricetidae. This study notifies the first case of furuncular obligatory myiasis in a dog in Central Brazil, in the Federal District, caused by Cuterebra apicalis. Case: In November 2009, an adult female Poodle dog (eight years old), was received from an urban area of the Federal District (Vicente Pires), an area close to large remnants of Cerrado stricto sensu. The dog was treated at a private veterinary clinic in Brasilia. The animal presented a furuncular myiasis in the lumbar region. Larvae were detected at the lesion site, which was collected for clinical veterinary analysis and sent for identification, on a 20 mL container with a third of its volume filled with vermiculite to safeguard the integrity of the material. [...](AU)

Record of Myiasis by Cuterebra apicalis in Domestic Dog in the Central Region of Brazil / Registro de miíase por Registro de miíase por Cuterebra apicalis em cão doméstico na região Central do Brasil

Background: Cuterebrosis is a furuncular myiasis caused by a dipterous from the genus Cuterebra. These flies are highly species-specific in relation to their hosts, being mostly common to rodents, lagomorphs and marsupials, with the development of a large subcutaneous furuncle as the main clinical manifestation. The most important microscopic alterations are the invasion of the damaged area by neutrophils, lymphocytes, macrophages, eosinophils and mast cells and the proliferation of fibroblasts and endothelial cells. However, the Cuterebrosis can occur in domestic animals, causing the formation of an atypical parasitic cycle, with the development of significant and severe clinical signs due to the erroneous migration of larvae, a situation not observed in typical hosts. Neuritis has been verified in cats due to the migration triggered by the larvae, causing irreversible damage to the central nervous system. In Brazil no reports of cases of myiasis in dogs and cats have been reported for any species of Neotropical Cuterebra. One of the species most commonly found in studies parasitizing mammals in the Midwest is Cuterebra apicalis. However, this Diptera has only been found parasitizing marsupials Didelphidae rodents and rodent Cricetidae. This study notifies the first case of furuncular obligatory myiasis in a dog in Central Brazil, in the Federal District, caused by Cuterebra apicalis. Case: In November 2009, an adult female Poodle dog (eight years old), was received from an urban area of the Federal District (Vicente Pires), an area close to large remnants of Cerrado stricto sensu. The dog was treated at a private veterinary clinic in Brasilia. The animal presented a furuncular myiasis in the lumbar region. Larvae were detected at the lesion site, which was collected for clinical veterinary analysis and sent for identification, on a 20 mL container with a third of its volume filled with vermiculite to safeguard the integrity of the material. [...]