Distribution of phoretic mites and lice in Pseudolynchia canariensis living on pigeons and the relationship with seasonality, carrier sex, plumage coloration and age of definitive hosts.

Among the parasites, some groups that have a limited capacity for locomotion, such as mites and lice, the transmission is challenging to win. These ectoparasites disperse through direct contact between hosts or, in some cases, through phoresy. However, these processes are not well-documented in detail because they are difficult to observe and quantify. In the present study, the patterns of distribution of skin mites and phoretic lice on hippoboscid louse fly Pseudolynchia canariensis sampled from Columba livia were evaluated. The analyzed pigeons were juveniles and adults, with three distinct plumage colors: blue checker, spread, or wild type, and were caught over 24 months. A total of 1,381 hippoboscid flies were collected on 377 hosts. The plumage color did not influence the infestation patterns of louse flies on juvenile and adult pigeons, nor did it influence the infestation patterns of skin mites and phoretic lice on the hippoboscid flies. However, the environmental temperature was directly related to higher prevalence, mean infestation intensity, and phoretic species richness on P. canariensis during the hottest seasons. Furthermore, a higher abundance of phoretic mite eggs, including embryonated eggs, was observed in females of P. canariensis in all seasons.

Organic and conventional agriculture: Conventional rice farming causes biochemical changes in Astyanax lacustris.

World food production is directly related to human population growth. Chemicals are constantly applied to pest control in crops to increase productivity. Therefore, sustainable alternatives are needed to reduce environmental impacts. The biochemical responses in liver and muscle of Astyanax lacustris collected in different rice planting systems were analysed. Ten fish were collected in organic rice cultivation systems and conventional as well as water and sediment for pesticide analysis. In water from conventional system, bentazon (56.1 µg L-1), fipronil (0.226 µg L-1) and propoxur (0.141 µg L-1) were found, while azoxystrobin and quinclorac were below the limit of quantification (LOQ). There were no pesticides in the sediment from the conventional system. In the water of the organic system, only propoxur (below the LOQ) was registered. Metalaxil (0.025 µg kg-1) were verified in the sediment, while diphenoconazole, dinoxifene and tebuconazole were below the LOQ. The presence of these pesticides in crops with an organic production system may be related to proximity to crops to conventional production systems. Besides this, the amount is very low as compared with conventional system. Muscle glycogen, protein and amino acid levels were higher in fish collected in organic ponds. Lactate and ammonia levels were higher in conventional cultures. Lipids and proteins had greater oxidative damage in both tissues in the conventional system. Although pesticides were detected in organic sediments, the parameters of metabolic and oxidative damage were probably related by exposure to higher concentrations of pesticide in the water or by the lower oxygen content of conventional systems. However, fish mortality was not observed during collections. Despite being an anthropic environment, areas of organic cultivation seem to present better conditions for the survival of A. lacustris.

How do seasonality and host traits influence the distribution patterns of parasites on juveniles and adults of Columba livia?

Parasites may influence host fitness and consequently exert a selective pressure on distinct phenotypes of the host population. This pressure can result in an evolutionary response, maintaining only individuals with certain traits in the population. The present study was aimed at identifying the morphological characteristics of juveniles and adults of Columba livia that may influence the distribution patterns of lice, Pseudolynchia canariensis and Haemoproteus columbae and how the populations of these parasites vary throughout the seasons of the year. Between July 2012 and July 2014, 377 specimens of C. livia were captured. We observed a significant increase in the mean intensities of infestation by pigeon flies and lice, as well as in species richness of ectoparasites during the warmest seasons, suggesting a reproductive synchrony between ectoparasites and host species. Bill length, body mass, and body length did not affect the infestation levels of ectoparasites on adults and juveniles of C. livia with three distinct plumage colors. In juveniles, plumage color affected only the mean intensity of infestation by lice, with Spread individuals as the most infested. This indicates that melanin in feathers was not an effective barrier against ectoparasites.

Assembleia de aves na area urbana do municipio de Pelotas, Rio Grande do Sul, Brasil

Urbanization causes changes in the composition and diversity of biotic communities. The goals of this work are to present a list of bird species that use the urban area in the city of Pelotas (RS), in the southernmost end of Brazil, and to describe the bird assemblages structure underlining the richness, composition, and relative abundance of species and their seasonal variability. Data collection took place between October 2007 and September 2008, at 216 fixed points, distributed in groups of 6 equidistant points at each 200 meters in streets with varied levels of urbanization, sampled once a season. The observer stayed for 8 minutes at each point, resulting in a sampling effort of 28.8 hours each season and 115.2 hours during the year. A total of 9,595 contacts of 84 bird species were found, belonging to 34 families and 14 orders. In regard to relative abundance, 72 species presented less than 200 contacts; 7 presented between 200 and 1,000; and 4 presented over 1,000 contacts. The species with more than 1,000 contacts were Furnarius rufus, Columba livia, Myiopsitta monachus, and Pitangus sulphuratus, accounting for 5,136 contacts. In all 84 species, 67 were present in less than 20% of the sampled points; 7 were registered at between 20-40% and between 40-60% of the points; and 3 were sighted at between 80-100% of the observation points. Species with the highest frequency of occurrence were P. sulphuratus, Passer domesticus, and F. rufus. Total richness ranged from 55 species in the fall to 61 in the winter. Of the 84 species, 21 were present in 1 season, 17 in 2, 9 in 3, and 37 were present in all four seasons. The season with the highest relative abundance was spring, with 2,936 contacts; the one with the least abundance was autumn, with 2,149 contacts. The bird assemblages presented a representative richness relative to the region, though very few species are abundant and well distributed. Such pattern may be a reflection of the low quality and heterogeneity of the urban matrix, which has few parks and green areas, no reserves with native vegetation and lakes, and a low degree of tree coverage.

A urbanização altera a composição e diversidade das comunidades bióticas. Os objetivos do trabalho são apresentar a lista de espécies de aves que utilizam a área urbana do município de Pelotas (RS), no extremo sul do Brasil, e descrever a estrutura da assembleia com ênfase na riqueza, composição e abundância relativa de espécies e suas variações sazonais. A coleta de dados ocorreu entre outubro de 2007 e setembro de 2008, em 216 pontos fixos de observação distribuídos em grupos de seis pontos em ruas com todos os graus de urbanização, que foram amostrados uma vez por estação. O observador permaneceu oito minutos em cada um dos pontos, o que resultou no esforço amostral de 28,8 horas em cada estação e 115,2 horas no ano. Foram registrados 9.595 contatos de 84 espécies de aves pertencentes a 34 famílias e 14 ordens. Quanto à abundância relativa, 72 espécies apresentaram menos de 200 contatos; sete apresentaram entre 200 e 1000; e quatro apresentaram mais de 1000 contatos. As espécies com mais de 1000 contatos foram Furnarius rufus, Columba livia, Myiopsitta monachus e Pitangus sulphuratus, totalizando 5136 contatos. Das 84 espécies, 67 estiveram presentes em menos do que 20% dos pontos amostrados; sete foram registradas entre 20 e 40% e entre 40 e 60% dos pontos; e três foram visualizadas entre 80 e 100% dos pontos. As espécies com maior frequência de ocorrência foram P. sulphuratus, Passer domesticus e F. rufus. A riqueza variou de 55 espécies, no outono, até 61, no inverno. Das 84 espécies, 21 estiveram presentes em uma estação, 17 em duas, nove em três e 37 estiveram presentes em todas as estações. A estação em que se obteve maior abundância relativa foi a primavera, com 2936 contatos, e a menor foi o outono, com 2149 contatos. A assembleia de aves apresentou riqueza representativa se comparada com a região, porém, poucas espécies são abundantes e bem distribuídas. Esse padrão pode ser reflexo da baixa qualidade e heterogeneidade da matriz urbana, que possui poucas praças e parques, não possui áreas de reserva de vegetação nativa e lagos e possui baixo grau de arborização.

Community of arthropod ectoparasites of two species of Turdus Linnaeus, 1758 (Passeriformes: Turdidae) in southern Rio Grande do Sul, Brazil.

This study was aimed at describing the community of arthropod ectoparasites associated with sympatric populations of Turdus amaurochalinus and Turdus rufiventris and analyzing the aggregation patterns of the chewing lice species, during reproductive and nonreproductive periods, of both Turdus species in three areas of the Atlantic forest in southern Rio Grande do Sul state (RS), Brazil. Altogether, we captured 36 specimens of T. amaurochalinus and 53 specimens of T. rufiventris. We identified two families of chewing lice, Menoponidae and Philopteridae, with Myrsidea and Brueelia as the most prevalent and abundant on both host birds. The lowest aggregation levels of chewing lice Myrsidea and Brueelia occurred during the reproductive period of both host species, suggesting a reproductive synchronization and a dispersion period. The most prevalent feather mite on T. amaurochalinus was Proctophyllodes weigoldi, and on T. rufiventris, Trouessartia serrana. Analges sp. and Pteronyssoides sp. were not observed on T. rufiventris. We identified three species of ticks; Ixodes auritulus was the most prevalent and abundant on the birds. Ornithoica vicina was the only hippoboscid fly collected, and only on T. amaurochalinus. The richness of ectoparasites was greater on T. amaurochalinus than on T. rufiventris. For T. amaurochalinus, the mean richness was lesser in winter compared to spring and autumn; however, we observed no variation in the mean richness of ectoparasites for T. rufiventris during the same seasons.

Comportamento alimentar aquático de Liophis jaegeri (Günther 1858) (Serpentes, Dipsadidae) em cativeiro / Aquatic feeding behavior of Liophis jaegeri (Günther 1858) (Serpentes, Dipsadidae) in captivity

Os itens que compõem a dieta das espécies são peças fundamentais na definição de sua dimensão de nicho e interferem, em última análise, em processos de estruturação das comunidades. As necessidades relacionadas à alimentação direcionam o modo pelo qual as espécies usam o ambiente. Apesar de se tratar de uma espécie com ampla distribuição geográfica, existem poucos estudos a respeito da biologia geral e do comportamento alimentar de Liophis jaegeri. Os estudos disponíveis indicam se tratar de uma espécie associada à ambientes alagados, porém, a importância de presas aquáticas na dieta desta serpente tem recebido pouca atenção. Em geral os estudos disponíveis sugerem que a presença de presas aquáticas (peixes e girinos) no trato digestivo de indivíduos dissecados seja resultado de ingestões acidentais. No presente estudo, a partir de gravações em vídeo realizadas em cativeiro, apresentamos dados inéditos que revelam a habilidade de L. jaegeri forragear em ambiente aquático, sendo capaz de detectar, subjugar e ingerir de modo eficiente peixes da espécie simpátrica Cheirodon interruptus. Tais informações indicam que a relevância de presas aquáticas na dieta desta serpente possa ser maior do que o até então apresentado pela literatura. Consequentemente, a disponibilidade de corpos d'água e de peixes podem influenciar os padrões de distribuição e abundância de indivíduos desta serpente na natureza.

Dietary composition is an essential component in niche dimension and interferes in the community structuring process. The needs related to feeding behavior drives the way species use their habitats. Despite the wide geographical distribution of Liophis jaegeri, studies concerning its general biology and feeding behavior are very scarce. The available information indicates that L. jaegeri is associated to humid or flooded habits, however the importance of aquatic preys in their diet has not received much attention. In general, the available information suggests that the presence of tadpoles and fishes in the digestive tract of dissected snakes are the result of incidental ingestion. In the present study, we present information on the ability of L. jaegeri to forage in aquatic habitats. Using video recordings made in captivity, we observed that snakes were able to detect, subdue and ingest efficiently the sympatric fish Cheirodon interruptus. These observations suggest that the importance of aquatic preys is higher than previously reported in the literature. Therefore, we believe that the existence of water bodies and the availability of aquatic preys play important roles in the habitat suitability for L. jaegeri snakes.