Assessing the influence of geographic distance in parasite communities of an exotic lizard

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.

From insect-plant interactions to ecological networks

Abstract Since its inception, biodiversity has largely been understood as species diversity and assessed as such. Interactions among species or functional groups are gradually becoming part of an expanded concept of biodiversity. As a case study of the development of a research program in biodiversity, we summarize our multi-decade studies on interactions of Asteraceae and flowerhead-feeding insects in Brazil. Initially, host species were treated as independent replicates in order to assess the local and turnover components of their herbivore diversity. Research then expanded into sampling entire interactive communities of host plants and their associated herbivores in different localities and regions, enabling new research lines to be pursued. Interaction diversity could be assessed and factored into spatial and among-host components, suggesting a new field of interaction geography. Second, host specialization, a key component of interaction diversity, was reframed considering simultaneously relatedness and local availability of plant hosts. Third, with the influence of complex network theory, community-wide species interactions were probed for topological patterns. Having identified the modular structure of these plant-herbivore systems, later we demonstrated that they fit a compound hierarchical topology, in which interactions are nested within large-scale modules. In a brief survey of research funded by Fapesp, especially within the Biota-Fapesp program, we highlight several lines of internationally recognized research on interaction diversity, notably on plant-frugivore and plant-pollinator interactions, together with new theoretical models. The interplay of field studies with new theoretical and analytical approaches has established interaction diversity as an essential component for monitoring, conserving and restoring biodiversity in its broader sense.

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

OBJECTIVES AND DESIGN

Knowledge of which and how many species are part of an ecosystem is fundamental to understanding the diversity of organisms, including parasitic organisms that vary widely among host populations. This study describes the composition, infection patterns, and similarity in composition of helminths associated with P. albifrons, P. cicada, and P. cuvieri.

MATERIALS AND METHODS

Four samplings were carried out in two caatinga areas in the southern region of Ceará State, Brazil. The specimens were collected by active search, necropsied, and surveyed for helminths. The infection patterns for all helminth species found were estimated through prevalence, mean abundance, and mean intensity of infection.

RESULTS

A total of 242 helminth specimens were collected from 264 hosts-100 Physalaemus albifrons with overall prevalence of 20%, 93 Physalaemus cicada with overall prevalence of 27%, and 71 Physalaemus cuvieri with overall prevalence of 15%. Ten parasite taxa with a mean of one-three parasite species per host were identified. The nematode Raillietnema spectans was present in the three host species and had the highest prevalence.

CONCLUSIONS

The results of this study represent 38.4% of known parasites for the species of the subfamily Leiuperinae, and 52.6% for the species of Physalaemus. Four parasite taxa (Oswaldocruzia cf. mazzai, Raillietnema spectans, Schrankiana schranki, and Cylindrotaenia americana) are new records for the host species studied, contributing to the knowledge of the parasitic interactions of amphibians of the genus Physalaemus.

Helminth parasites of Phyllodactylidae and Gekkonidae lizards in a Caatinga ecological station, northeastern Brazil

Abstract We investigated the parasites of five lizard species belonging to Phyllodactylidae (Phyllopezus pollicaris and Gymnodactylus geckoides) and Gekkonidae (Hemidactylus agrius, Lygodactylus klugei and Hemidactylus brasilianus) families in a semiarid region of Brazil. Six nematode species were identified: Parapharyngodon alvarengai and Spauligodon oxkutzcabiensis (Pharyngodonidae), Physaloptera lutzi (Physalopteridae), Skrjabinelazia intermedia (Seuratidae), Trichospirura sp. (Rhabdochonidae) and Piratuba sp. (Onchocercidae), and a cestode species, Oochoristica sp. (Linstowiidae). The most prevalent species were Spauligodon oxkutzcabiensis, which infected P. pollicaris (75%), and Parapharyngodon alvarengai, which infected G. geckoides (29%). South American lizards were identified as being new hosts for the Trichospirura genus (a usual parasite of mammals), and there were 16 new occurrences of parasite species in the five lizard species studied herein.

Nematode infection patterns in a Neotropical lizard species from an insular mountain habitat in Brazil

Neotropical lizards are known to harbour rich nematode parasite faunas; however, knowledge of the diversity and patterns of infection are still lacking for many species. This is true for the genus Tropidurus, in which data on patterns of parasitism are known for only approximately 11 of its 30 species. We show that the nematode fauna associated with a population of Tropidurus montanus is composed of three species of host-generalist parasites with high overall prevalence. Male and female lizards did not differ in infection pattern and there was no relationship between host body size and intensity of infection for the most prevalent parasite species. Nevertheless, overall prevalence changed seasonally, with a higher proportion of parasitized individuals being found in the dry period than in the rainy period. We discuss our findings in the context of diet patterns of T. montanus, which we suggest may explain the similarities in prevalence and intensity of infection between the sexes. In addition, seasonal changes in diet are considered to be related to the observed differences in prevalence between dry and rainy periods.