A wingless fly on a winged mammal: host-parasite dynamics between Basilia travassosi (Diptera: Nycteribiidae) and Myotis lavali (Chiroptera: Vespertilionidae).

Nycteribiidae encompasses a specialized group of wingless blood-sucking flies that parasitize bats worldwide. Such relationships are frequently species- or genus-specific, indicating unique eco-evolutionary processes. However, despite this significance, comprehensive studies on the relationships of these flies with their hosts, particularly in the New World, have been scarce. Here, we provide a detailed description of the parasitological patterns of nycteribiid flies infesting a population of Myotis lavali bats in the Atlantic Forest of northeastern Brazil, considering the potential influence of biotic and abiotic factors on the establishment of nycteribiids on bat hosts. From July 2014 to June 2015, we captured 165 M. lavali bats and collected 390 Basilia travassosi flies. Notably, B. travassosi displayed a high prevalence and was the exclusive fly species parasitizing M. lavali in the surveyed area. Moreover, there was a significant predominance of female flies, indicating a female-biased pattern. The distribution pattern of the flies was aggregated; most hosts exhibited minimal or no parasitism, while a minority displayed heavy infestation. Sexually active male bats exhibited greater susceptibility to parasitism compared to their inactive counterparts, possibly due to behavioral changes during the peak reproductive period. We observed a greater prevalence and abundance of flies during the rainy season, coinciding with the peak reproductive phase of the host species. No obvious correlation was observed between the parasite load and bat body mass. Our findings shed light on the intricate dynamics of nycteribiid-bat interactions and emphasize the importance of considering various factors when exploring bat-parasite associations.

Gastrointestinal helminths associated with three species of freshwater turtles in the Pampa biome, southern Brazil.

Maintenance of the life cycle of a wide diversity of helminths depends on the aquatic environment. Freshwater turtles are considered one of the main groups in these ecosystems due to their high density and biomass. However, there is little information on the infection parameters of helminths associated with the Chelidae species Hydromedusa tectifera, Phrynops hilarii, and Acanthochelys spixii that occur in the Pampa biome. Therefore, this study aimed at analyzing the gastrointestinal helminth assemblage of the three species. Analyses showed that A. spixii was associated with 11 helminth taxa while P. hilarii and H. tectifera were parasitized by eight taxa each. The gastrointestinal helminth assemblage of A. spixii and H. tectifera showed high similarity by the Morisita index. Infections suggest that the helminth fauna is directly related to the diet of the hosts, since A. spixii, P. hilarii, and H. tectifera are generalist and/or opportunistic with diets composed of various invertebrates, which, in turn, are part of the life cycles as intermediate hosts of most of the identified helminths. Thus, this study highlights not only the importance of helminthological research for the understanding of the biology of host organisms, but also the need for conservation of flooded areas characteristic of the Pampa biome, which is essential to maintain the diversity of the ecosystem.

Rhinonyssus rhinolethrum (Trouessart, 1895) (Mesostigmata: Rhinonyssidae) in Netta peposaca (Vieillot, 1816) (Anseriformes: Anatidae) from Southern Brazil.

Netta peposaca is an anatid endemic to the South American continent and Rhinonyssus rhinolethrum is a rhinonissid mite of wide geographical distribution parasitizing several species of anatids. The association between these organisms has been reported in Argentina; however, the number of birds examined and the parasite indices have not been reported. Thus, the objective of this study was to know the diversity of nasal mites associated with N. peposaca in southern of Brazil and the parasitological indices. The nasal cavities of 30 birds from two locations in Rio Grande do Sul, Brazil, were examined to collect mites. Rhinonyssus rhinolethrum occurred in 16.67% of the birds with an infection intensity of 3-24 mites/host. Infections in male and female hosts showed no significant differences. This study records for the first time R. rhinolethrum and its infection indices in N. peposaca in the southern of Brazil.

Rhinonyssidae (Acari) in the house sparrows, Passer domesticus (Linnaeus, 1758) (Passeriformes: Passeridae), from southern Brazil / Ácaros nasais Rhinonyssidae parasitos de Passer domesticus (Linnaeus, 1758) (Passeriformes: Passeridae) no extremo sul do Brasil

Abstract We report the occurrence and infection parameters of two species of nasal mites in Passer domesticus (Linnaeus, 1758) (house sparrow). Nasal passages, trachea, lungs, and air sacs of 100 house sparrows captured in an urban area at the city of Pelotas, State of Rio Grande do Sul, southern Brazil, were examined with a stereomicroscope. The mite, Sternostoma tracheacolum Lawrence, 1948 was present in the trachea and/or lungs (or both) of 13 birds (13%) at a mean intensity of 6.7 mites/infected host. Ptilonyssus hirsti (Castro & Pereira, 1947) was found in the nasal cavity of 1 sparrow (1%); coinfection was not observed in this bird. There was no significant difference in the prevalence and mean intensity of infection of S. tracheacolum between male and female birds. To our knowledge, this is the first study reporting the occurrence of S. tracheacolum in P. domesticus in Brazil and the presence of P. hirsti in P. domesticus from Rio Grande do Sul, Brazil. This is the first survey to provide the infection parameters of each of these mites in house sparrows.

Resumo O objetivo deste estudo foi relatar duas espécies de ácaros nasais parasitos do sistema respiratório de Passer domesticus (Linnaeus, 1758) (pardal) e seus respectivos índices parasitológicos. Para isso, foram examinados ao estereomicroscópio, cavidade nasal, traqueia, pulmão e sacos aéreos de 100 pardais capturados na área urbana de Pelotas, Rio Grande do Sul, Brasil. Sternostoma tracheacolum Lawrence, 1948 ocorreu na traqueia e/ou pulmão de 13 aves (13%) com intensidade média de 6,7 ácaros/hospedeiro infectado e Ptilonyssus hirsti (Castro & Pereira, 1947) na cavidade nasal de um único pardal (1%), não havendo coinfecção. A prevalência e intensidade média de infecção por S. tracheacolum entre hospedeiros machos e fêmeas não apresentou diferença significativa. Este relato caracteriza o primeiro registro de S. tracheacolum parasitando P. domesticus no Brasil e de P. hirsti em pardais no RS, Brasil, e seus respectivos índices de infecção.

Metazoan parasites of Geophagus brasiliensis (Perciformes: Cichlidae) in Patos lagoon, extreme south of Brazil / Metazoários parasitos de Geophagus brasiliensis (Perciformes: Cichlidae) da Lagoa dos Patos, extremo sul do Brasil

Abstract This study has evaluated the parasitic fauna of 79 pearl cichlids (Geophagus brasiliensis) from the estuary of Patos Lagoon (31° 57' S and 52° 06' W), Rio Grande do Sul, Brazil, during the months of May and June in 2011 and 2012. All the hosts analyzed were infected with at least one species of parasite. A total of eleven metazoa were identified in 459 specimens collected. The trematode Austrodiplostomum compactum (34.2%) and ergasilids Ergasilus lizae (32.9%) and Gauchergasilus lizae (32.9%) were the most prevalent species. The trematodes Thometrema overstreeti and Posthodiplostomum sp. had significantly higher prevalence in fish longer than 20 cm. The sex of the host had no effect on parasite prevalence and abundance. Pearl cichlids are registered as a new host for the trematodes Lobatostoma sp., Homalometron pseudopallidum and Thometrema overstreeti, for the ergasilids Ergasilus lizae and Gauchergasilus euripedesi and for the argulid Argulus spinolosus. The crustacean E. lizae is recorded in Rio Grande do Sul for the first time.

Resumo Este estudo avaliou a fauna parasitária de 79 Geophagus brasiliensis (acarás) proveniente do Estuário da Lagoa dos Patos (31°57’S e 52°06’W), Rio Grande do Sul, no período de Maio e Junho de 2011 a 2012. Todos os hospedeiros analisados estavam infectados com pelo menos uma espécie de parasito. Um total de onze metazoários foi identificado em 459 espécimes coletados. O trematoda Austrodiplostomum compactum (34,2%) e os ergasilídeos Ergasilus lizae (32,9%) e Gauchergasilus lizae (32,9%) foram às espécies mais prevalentes. Os trematodeos Thometrema overstreeti e Posthodiplostomum sp. apresentaram uma prevalência significativamente maior nos peixes acima de 20 cm. O gênero sexual dos hospedeiros não apresentou influência sobre a prevalência e a abundância parasitária. Geophagus brasiliensis é registrado como um novo hospedeiro para os trematódeos Lobatostoma sp., Homalometron pseudopallidum e Thometrema overstreeti, para os ergasilídeos Ergasilus lizae e Gauchergasilus euripedesi e para o argulídeo Argulus spinolosus. O crustáceo E. lizae é registrado pela primeira vez no Rio Grande do Sul.