Helminths Associated with Three Physalaemus Species (Anura: Leptodactylidae) from Caatinga Biome, Brazil

Pattern of anuran infection by acanthocephalans from the Cerrado, Northeastern Brazil with a summary for South America

In Brazil, acanthocephalans parasitise anurans in several biomes. In the present study, we performed an analysis of acanthocephalan infections across 175 anuran individuals from the Cerrado biome, belonging to ten species: Boana raniceps, Pithecopus hypochondrialis, Scinax fuscomarginatus, Scinax x-signatus, Leptodactylus pustulatus, Leptodactylus macrosternum, Leptodactylus vastus, Physalaemus cuvieri, Adenomera hylaedactyla, and Elachistocleis piauiensis. We also verified the specificity of the parasites using the STD* index. Additionally, we conducted a survey of acanthocephalan infection in anurans in South America. The studied assemblage in the Brazilian Cerrado presented 57 parasitised hosts of 175 specimens (overall prevalence: 32.6%). In total, 437 acanthocephalans cystacanths were recorded, among which 286 presented the same morphotype but could not be identified, 148 belonged to the genus Centrorhynchus, and three belonged to Oncicola. Unidentified acanthocephalans had a higher prevalence in L. vastus (53.85%) and the highest intensity was in L. pustulatus (17±16). The highest prevalence of Centrorhynchus sp. was in the species S. fuscomarginatus (28.57%), while the highest intensity was observed in L. vastus (111). The taxon Oncicola sp. it had a prevalence of 3.23% and an intensity of 3 only in S. x-signatus. The highest specificity was recorded for Oncicola sp. (STD*= 1), whereas the lowest was found in Centrorhynchus sp. (STD*= 2.21). Finally, according to the survey for South America, we found ten records of acanthocephalan taxa parasitizing 58 species of anurans distributed in seven countries (Brazil with the most records).

Effect of altitude and spatial heterogeneity on the host-parasite relationship in anurans from a remnant humid forest in the brazilian semiarid

In the present study, we investigated the effect of habitat heterogeneity, elevation gradient, and phylogenetic distance of host species on the abundance and richness of anuran endoparasites, assuming that parasites follow the distribution of their hosts independently of environmental variation. We collected 192 anurans distributed in three altitude ranges: 100-200 m, 400-500 m, and 700-800 m. We performed discriminant principal component analysis to analyze the interrelationships between environmental heterogeneity and the distribution of parasite and host species in the formation of species groups in each altitude range. We estimated the niche width and parasite overlap, using host species as a variable, and assessed whether parasite abundance is more influenced by historical (distance host phylogeny) or ecological effects in each altitude category and overall. Finally, we use network analyses to understand how interactions between parasites and hosts are formed along the altitude gradient. We found 22 parasite species, and the overall prevalence of infection was 74%. In our study, we did not identify environmental (altitude gradients and heterogeneity) or phylogenetic effects acting on the parasite species diversity. Overall, our results suggest that the parasites are distributed following the dispersal of their hosts and are dispersed among most anuran species.

Endoparasite community of anurans from an altitudinal rainforest enclave in a Brazilian semiarid area

In the present study, we aimed to describe the composition of endoparasites associated with anurans from an altitudinal rainforest enclave in northeastern Brazil. Additionally, we tested if microhabitat use influences endoparasite abundance and richness, as well as the hypothesis that larger frogs tend to be more parasitized. We sampled 306 individuals from 25 anuran species that were necropsied and analysed using a stereomicroscope. The total endoparasite prevalence was 79.08%, with a parasitic community consisting of 46 taxa. Overall, we found the common pattern described for Neotropical amphibians, which is the predominance of generalist and direct-cycle parasites. Twenty new host records and two possible new parasite species were found, highlighting the importance of this type of inventory. We also observed that microhabitat use was associated with a significant difference in parasite richness between groups, in which arboreal and terrestrial species, and aquatic and arboreal species contributed to these differences. Moreover, larger frogs tended to be more parasitized regarding only an interspecific view. Our results suggest that parasite richness is directly related to infection cycle and how the host exploits its habitat.

Helminths Infecting Sympatric Congeneric Treefrogs in Northeastern Brazil

PURPOSE

We aimed to describe the helminth fauna associated with two sympatric congeneric treefrogs species (Boana multifasciata and Boana raniceps) from a highland marsh in northeastern Brazil. In addition, we investigate the body size influence on parasitological descriptors in these treefrogs, in which we expected that larger frogs would have greater abundance and richness helminths too, and no differences with respect to helminth composition once both hosts are exposed to similar environmental conditions.

METHODS

We collected anurans during the rainy season from 11 January to 09 February 2019, using visual and auditory searches in breeding environments. We analysed the presence of ectoparasites under an epidermis, oral cavity, and endoparasites present in the organs. Using a Linear mixed-effects model we tested the relationship between the host body size (length and weight) and helminths abundance and richness. In addition, we used the ANOSIM R test to investigate the differences between the hosts with respect to helminth composition.

RESULTS

We recorded 37 individuals (15 specimens of B. multifasciata and 22 of B. raniceps), in which 89.1% of them were infected by at least one helminth species. We found 355 helminths from 12 taxa parasitizing the two treefrogs, but just three parasite taxa were common to both species. All identified helminth species found in B. multifasciata are new records and four are new records for B. raniceps. In addition, we present the first record of Cosmocerca paraguayensis in Brazil. We found no support for the hypothesis that larger frogs tend to be more parasitized, at least for congeneric species, and sympatric hosts species have similar helminth composition. We also present a compilation of helminths occurring in treefrogs belonging to the Boana genus in South American, increasing our knowledge of the parasitic diversity of Neotropical anurans.

CONCLUSION

Our results suggest a lack of knowledge about helminth fauna associated with amphibians even for common and widely distributed species, such as Boana spp., and demonstrate the need to deepen our knowledge about host parasitic relationships, especially in the Neotropical region.

Endoparasites of Adelophryne maranguapensis Hoogmoed, Borges & Cascon, 1994 (Anura, Eleutherodactylidae), an endemic and threatened species from an altitude swamp in northeastern Brazil

Adelophryne maranguapensis is an endangered anuran species endemic to the Maranguape residual mountain, Ceará State, northeaster Brazil, which is under strong anthropogenic pressure. There are still few studies on the natural history of this species that allow a better understanding of its biology and can provide the basis for conservation actions. Studies on endoparasitism are an important source for the comprehension of ecological relationships, as well as for providing information on host biology and its relevance to ecosystems. Thus, we present information about the endoparasites helminths, the relationship of parasite abundance with the size of individuals and the parasite difference between the sexes in A. maranguapensis, to elucidate some characteristics in the host-parasite relationship and the use of the area of this anuran. We analysed 107 specimens deposited in the Herpetological Collection of the Federal University of Ceará, sampled from 2010 to 2012. Total prevalence of 24.30% was recorded, and four parasitic taxa were identified, Aplectana sp., Physaloptera sp., Parapharyngodon sp. and an unidentified Ascarid. No relationship between the abundance of parasites and snout-vent length was found and the parasite difference between the sexes. Even though identification of the parasites at species level was not possible, A. maranguapensis follows a common pattern in parasitism of Neotropical species.

Ecological specificity explains infection parameters of anuran parasites at different scales

Understanding the determinants of parasite infection in different hosts is one of the main goals of disease ecology. Evaluating the relationship between parasite–host specificity and infection parameters within host communities and populations may contribute to this understanding. Here we propose two measures of specificity that encompasses phylogenetic and ecological relatedness among hosts and investigated how such metrics explain parasite infection prevalence and mean infection intensity (MII). We analysed the parasites associated with an anuran community in an area of Atlantic Forest and used the number of infected hosts and the net relatedness index to calculate the phylogenetic and ecological specificities of the parasites. These specificity measures were related to infection metrics (prevalence and MII) with generalized linear mixed models at community (all hosts) and population (infected host species) scales. Parasite prevalence was correlated with the number of infected hosts and, when considering only multi-host parasites, was positively related to parasite ecological specificity at community and population scales. Thus, parasite species have similar prevalences in ecologically closer hosts. No relationship was found for parasite MII. Incorporating ecological characteristics of hosts in parasite specificity analyses improves the detection of patterns of specificity across scales.

Helminth’s assemblage of a small frog in the Brazilian semiarid: parasite-host-environment relationships

ABSTRACT. Parasite infections may contingency different aspects of the hosts’ lives, and are usually expected to directly or indirectly compromise host reproduction. However, although amphibians have historically been study models in parasite ecology, the effects of parasitism on amphibians’ reproduction remain unknown. Thus, we investigated how the parasite load varies as a function of climatic seasonality (rainy and dry season) and intrinsic host characteristics (size and sex), as well as the relationship between parasite load and reproductive investment in males and females of a small frog (Pseudopaludicola pocoto Magalhães, Loebmann, Kokubum, Haddad & Garda, 2014) in the Brazilian semiarid region. The parasitological parameters of the studied population were not influenced by the season of the year or by the hosts’ body size, but females of P. pocoto had a higher prevalence and intensity of infection than males. The number of oocytes and the volume of the testes were not related to the parasite load, revealing that the parasitism did not negatively impact the gonadal investment in P. pocoto. Our findings suggest that short-lived species, such as the tiny Pseudopaludicola species, have a high reproductive investment independent of their parasitic interactions. In addition, this should be true mainly in those species that live in seasonally dry environments, such as P. pocoto, in which reproduction is even more constrained by the shortened and unpredictable rainy period.

Nematodes of Proceratophrys ararype (Anura: Odontophrynidae), an endemic frog from the Araripe Plateau, northeastern Brazil

Abstract: Parasites are an important component of the global biomass, having significant roles in several regulatory mechanisms in the ecosystem. Parasitism is one of the most common ecological interactions on the planet. Studies have shown that the helminth fauna of only 8% of amphibian species in Brazil have been studied, and this percentage is lower for the Odontophrynidae family, with only four of the 50 species kown to occur in Brazil having been investigated. Here, we present the helminth fauna of Proceratophrys ararype, an anuran endemic to the “Brejo de Altitude” Chapada do Araripe (Araripe Plateau), northeastern Brazil. The infection parameters analyzed were prevalence, mean intensity of infection and mean abundance of parasites. We used the Pearson’s linear correlation coefficient to check the correlations between the abundance of the parasites with the snout-vent length (SVL) of hosts. To verify the degree of aggregation of parasites in hosts, we used the dispersion index. Out of 40 specimens examined, 19 specimens were infected with at least one parasite. The overall prevalence was 47.5% with a mean infection intensity of 18.93 ± 10.77. The endoparasitic community associated with P. ararype consisted of six species of parasites, with Falcaustra mascula having the highest prevalence (25%). Most parasites had a uniform dispersion index in the hosts and their abundance was unrelated to host size. Here, we also present a compilation of all parasites associated with host species of the genus Proceratophrys from South America. Overall, we found 23 species of parasites associated with five host species (P. ararype, P. appendiculata, P. boiei, P. cristiceps, P. mantiqueira). Of these, two species of parasites (Oswaldocruzia mazzai and Strongyloides sp.) represent new records for the genus Proceratophrys. Our results demonstrate the lack of studies on amphibian helminth fauna and fill an important knowledge gap on the diversity of parasites of Proceratophrys ararype, an endemic frog from the Araripe Plateau, northeastern Brazil.

A new species of Rhabdias (Nematoda: Rhabdiasidae), a lung parasite of Pseudopaludicola pocoto (Anura: Leptodactylidae) from north-eastern Brazil: description and phylogenetic analyses

Rhabdias pocoto n. sp. is herein described from the lungs of the swamp frog Pseudopaludicola pocoto Magalhães, Loebmann, Nogueira, Kokubum, Baptista, Haddad & Garda, 2014, from the Caatinga biome in the state of Ceará, in north-eastern Brazil. The new species is characterized by a body that dilates posteriorly, six small lips (protuberances) and two rounded lateral expansions of cuticular inflation on the anterior end, each containing an amorphous gland-like structure inside and a short and conical tail. Additionally, molecular analysis and comparison of the partial mitochondrial cytochrome c oxidase I sequence of R. pocoto n. sp. revealed genetic divergence between the new species and the sequences of Rhabdias spp. previously deposited in GenBank. Phylogenetic analysis grouped the new taxon into the R. pseudosphaerocephala species complex + R. glaurungi clade. The new discovery represents the 19th species of Rhabdias spp. described in the Neotropical region, the ninth in Brazil and the first species of Rhabdias found parasitizing South American frogs of the genus Pseudopaludicola, as well as the first Caatinga biome species of Rhabdias.