First record in Brazil of Epistylis sp. (Ciliophora) Adhered to Argulus sp. (Argulidae), a Parasite of Hoplias aimara (Eritrhinidae).

This paper records the first occurrence of Epistylis sp. on the body surface of Argulus sp. parasitizing Hoplias aimara from the upper Araguari River, in the eastern Amazon region, in the north of Brazil. Of the 16 specimens of H. aimara examined, 93.7% had their pelvic, caudal and pectoral fins and tegument infested by Argulus sp. (n = 73), which in turn were infested by Epistylis sp. The specimens of Epistylis sp. from the body surface of Argulus sp. were analyzed using Scanning Electron Microscopy (SEM). The present study also identified a widening of the geographic distribution of these two species of ectoparasites to the eastern Amazon region of Brazil.

Communities of parasite metazoans in Piaractus brachypomus (Pisces, Serrasalmidae) in the lower Amazon River (Brazil).

The aim of this study was to investigate the component community of parasite metazoans of Piaractus brachypomus in the lower Amazon River, northern Brazil. From 34 necropsied fish, 27,384 metazoan parasites were collected, such as Anacanthorus spathulatus, Mymarothecium viatorum and Notozothecium janauachensis (Monogenoidea); Spectatus spectatus and Contracaecum sp (Nematoda); Clinostomum marginatum and Dadaytrema oxycephala (Digenea); and Argulus carteri and Ergasilus sp. (Crustacea). The dominant species was S. spectatus followed by monogenoidean species, and there was aggregated dispersion of parasites, except for D. oxycephala and Contracaecum sp., which presented random dispersion. Positive correlation among the abundance of the three monogenoideans species were found, thus indicating that there was no competition between the species of these parasites on the gills of hosts. The abundances of some parasite species showed positive correlations with the size of the hosts, but the condition factor of the fish was not affected by the parasitism levels. It showed that this host had a metazoan community characterized by high species richness of metazoans, low evenness and high diversity of parasites, with prevalence of endoparasites, including larval stages. This was the first record of C. marginatum, A. carteri, Ergasilus sp. and Contracaecum sp. for P. brachypomus.

Parasite communities of the predatory fish, Acestrorhynchus falcatus and Acestrorhynchus falcirostris, living in sympatry in Brazilian Amazon.

This study investigated the parasite communities of wild Acestrorhynchus falcatus and Acestrorhynchus falcirostris populations living in sympatry in Brazilian Amazon. In these two hosts, a total of 12 parasite species e 1-9 parasite species were found per fish, and 10 of these species are metazoans. Eight species of parasites were common to both host species and four of them exhibited differences in abundance and/or prevalence. Parasite communities of the hosts were taxonomically similar (83%) and composed of both ectoparasites and endoparasites, and characterized by high prevalence and high abundance of endoparasites and an aggregated dispersion pattern. For A. falcirostris, the dominant parasite was Ichthyophthirius multifiliis, and for A. falcatus, it was Piscinoodinium pillulare. Shannon diversity and Berger-Parker dominance were similar for both hosts, while the parasites species richness and evenness showed differences influenced by the ectoparasites species. These two populations of hosts that inhabited the same geographical area had different sizes, but were exposed to the same infective stages, and acquired qualitatively and quantitatively similar endoparasites community, thus indicating that the amounts and types of prey congeneric that they were eating were similar. Therefore, the overlap in the same occurrence area play an important role in the parasite communities to these phylogenetically related hosts.

Host-parasite interaction between crustaceans of six fish species from the Brazilian Amazon.

Host-parasite interactions between crustaceans and six fish species (Psectrogaster falcata, Ageneiosus ucayalensis, Acestrorhynchus falcirostris, Hemiodus unimaculatus, Serrasalmus gibbus and Geophagus proximus) from a reservoir in eastern Amazon, northern Brazil, were investigated. Eight hundred and seventy-eight parasites belonging to three crustacean species, Excorallana berbicensis, Argulus chicomendesi and Ergasilus turucuyus, which parasitized the hosts? mouth, gills and tegument, were collected from 295 fish and examined. High infestation levels were caused by E. berbicensis on the body surface of the hosts. Excorallana berbicensis showed aggregate dispersion, except in S. gibbus, while E. turucuyus showed random dispersion in A. falcirostris. The host?s sex did not influence infestation by E. berbicensis, and high parasitism failed to affect the body conditions of the fish. In the case of some hosts, rainfall rates, temperature, dissolved oxygen levels and water pH affected the prevalence and abundance of E. berbicensis, the dominant parasite species. Results revealed that the environment and life-style of the hosts were determining factors in infestations by parasites. Current assay is the first report on E. berbicensis for the six hosts, as well as on A. chicomendesi for G. proximus and P. falcata.

Selection of Trichogramma pretiosum lineages for control of Grapholita molesta in peach.

Grapholita molesta (Lepidoptera: Tortricidae) é uma das principais pragas do pessegueiro no Brasil, causando perdas de 3-5% da produção. Dentre os agentes de controle biológico Trichogramma pretiosum (Hymenoptera: Trichogrammatidae) tem sido encontrado nos pomares de pessegueiros. O objetivo deste trabalho foi estudar a criação de T. pretiosum em ovos de G. molesta e Anagasta kuehniella (Lepidoptera: Pyralidae) e selecionar as linhagens de T. pretiosum com potencial de controle de G. molesta. A seleção de linhagens foi realizada com cinco populações de T. pretiosum coletadas em pomares de pessegueiro cultivados sob o sistema orgânico de produção. O estudo foi realizado em condições controladas de temperatura (25 ± 2°C), umidade relativa (70 ± 10%) e fotofase (14h). Ovos de G. molesta são hospedeiros adequados ao desenvolvimento de T. pretiosum uma vez que, nas variáveis estudadas número de ovos parasitados, porcentagem de parasitismo e razão sexual, os valores foram equivalentes aos criados em ovos de A. kuehniella . O maior parasitismo de ovos de G. molesta ocorreu com posturas de até 48h de desenvolvimento embrionário. Das linhagens de T. pretiosum coletadas, H08, PO8, PEL e L3M apresentaram melhor desempenho biológico, sendo, portanto, indicadas para estudos de semi-campo e campo para o controle biológico da mariposa-oriental.