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Sensory drive in colourful waters: Morphological variation suggests combined natural and sexual selection in an Amazonian fish
No full textNatural selection often shapes visual perception with respect to the lighting environment. For organisms that rely on visual communication for mating, environmental backscatter and bias in wavelength transmission affect the exchange of visual signals, which can mediate major changes in sexually selected traits. Based on the lighting environment, Amazon forest streams (igarapés) can be categorized into two major water types: clearwater and blackwater. The lighting environment is mostly transparent in clearwater, whereas retention of high amounts of dissolved organic carbon biases light towards the red and creates strong backscatter in blackwater igarapés. We investigated morphological differences among populations representative of lineages within the sailfin tetra Crenuchus spilurus, a sexually dichromatic Amazonian fish. We show that despite the broad geographical range of the nominal species, populations are similar for most measured morphological traits. However, eye diameter and characteristics of the fin ornaments revealed two distinct groups, corresponding to lineages from blackwater and clearwater igarapés. Our results lend support to the sensory drive hypothesis by suggesting that as a consequence of animals inhabiting different lighting conditions, natural selection affected visual perception and thus resulted in differences in sexual ornaments. © 2019 The Linnean Society of London, Biological Journal of the Linnean Society
Scale-dependent estimates of niche overlap and environmental effects on two sister species of Neotropical snakes
No full textDetecting ecological patterns is highly dependent on the spatial scale of the analysis. However, the importance of scale has been poorly explored when testing environmental influences and estimating niche overlap between animal species. In this study, we tested the hypotheses that: 1) environmental influences on species distribution at different geographic scales will be distinct, 2) niche overlap limits species local occurrence. We modeled ecological distributions of Philodryas argentea (n = 319) and P. georgeboulengeri (n = 61) in the Amazonian biome at different spatial scales: local, using regression analysis along 880 km transect with evenly distributed plots; and broad, modeling occurrence data with a Maximum Entropy algorithm. Variables that contributed to P. argentea occurrence were tree cover and elevation at local scale and annual temperature range for broad scale. For P. georgeboulengeri, the most important variables at local and broad scales were tree cover and elevation, respectively. Niche overlap was estimated at 23% and niches were not similar. We conclude: 1) detection of the most relevant variables for distribution of both species is dependent on spatial scale used; 2) although limited, co-occurrence of species at local scale seems to be allowed by the high niche dissimilarity observed in broad scale. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group
Progress on the phylogeny of the Omphalotaceae: Gymnopus s. str., Marasmiellus s. str., Paragymnopus gen. nov. and Pusillomyces gen. nov
No full textOmphalotaceae is the family of widely distributed and morphologically diverse marasmioid and gymnopoid agaric genera. Phylogenetic studies have included the family in Agaricales, grouping many traditionally and recently described genera of saprotrophic or parasitic mushroom-producing fungi. However, some genera in Omphalotaceae have not reached a stable concept that reflects monophyletic groups with identifiable morphological circumscription. This is the case of Gymnopus and Marasmiellus, which have been the target of two opposing views: (1) a more inclusive Gymnopus encompassing Marasmiellus, or (2) a more restricted Gymnopus (s. str.) while Marasmiellus remains a distict genus; both genera still await a more conclusive phylogenetic hypothesis coupled with morphological recognition. Furthermore, some new genera or undefined clades need more study. In the present paper, a phylogenetic study was conducted based on nrITS and nrLSU in single and multilocus analyses including members of the Omphalotaceae, more specifically of the genera belonging to the /letinuloid clade. The resulting trees support the view of a more restricted Gymnopus and a distinct Marasmiellus based on monophyletic and strongly supported clades on which their morphological circumscriptions and taxonomic treatments are proposed herein. The results also provide evidence for the description of two new genera: Paragymnopus and Pusillomyces. Pusillomyces manuripioides sp. nov. (type species of the genus) is described with morphological description, taxonomic and ecological remarks, and illustrations. © 2019, German Mycological Society and Springer-Verlag GmbH Germany, part of Springer Nature
Finishing plant diet supplemented with microalgae meal increases the docosahexaenoic acid content in Colossoma macropomum flesh
No full textThe need for a sustainable aquaculture is increasing the use of plant ingredients in replacement to fishmeal and fish oil in diets for tambaqui Colossoma macropomum, which is leading to not detectable levels of docosahexaenoic acid (DHA) in its flesh. We evaluated the effect of a finishing plant diet supplemented with 5% of microalgae meal from Schizochytrium sp. (MD) on tambaqui growth, on proximal composition and fatty acid content of its flesh, comparing it to a non-supplemented diet. One hundred and sixty-two fish (489.67 g) were distributed into six tanks (2,000 L) and fed the experimental diets for a 90-day period. Three fish per tank were euthanized for analyses every 15 days. The MD did not affect the growth and proximal composition of fish flesh. The MD increased the DHA content (from 14.81 to 38.60 mg/g of lipids) and the n-3:n-6 ratio (from 0.16 to 0.51) in the flesh of fish, beginning on the 15th day and reaching the highest DHA content on the 71st day (39.81 mg/g of lipids). We recommend C. macropomum to be fed with a finishing diet supplemented with microalgae meal for 71 days before slaughter to improve the DHA content and n-3:n-6 ratio in the flesh. © 2019 John Wiley & Sons Lt
The digestive tube of Piaractus brachypomus: gross morphology, histology/histochemistry of the mucosal layer and the effects of parasitism by Neoechinorhynchus sp.
No full textThe objective of the present study was to describe the histology and histochemistry of the mucosal layer of the digestive tube of Piaractus brachypomus, and the histopathology associated with parasitism by Neoechinorhynchus sp. The digestive tube of P. brachypomus consists of three macroscopically distinct portions: short, rectilinear and elastic-walled ooesophagus, J-shaped siphon stomach and a long intestine with rectilinear and curved portions, defined by patterns of villi as foregut, midgut, and hindgut. Histological and histochemical differences were observed in the mucosal layers of the different digestive tube regions, such as intense production of neutral and acidic mucous substances in the pseudostratified mucosal epithelium of the oesophagus; positive periodic acid Schiff reagent (PAS)reactions at the apex of the columnar epithelial cells of the stomach and increased intensity of histochemical reactions in the hindgut region. Neoechinorhynchus sp. was present in 85.7% of specimens examined, with a mean intensity of 7.4 ± 6.2 (±) and abundance of 6.33. Good health of the fish indicated by high relative condition factor values ( Kn ) and occurrence of only mild to moderate alteration in the mucosal layer indicated that Neoechinorhynchus sp. exhibits low pathogenicity towards P. brachypomus hosts in farming environments, with low levels of infection. © 2019 The Fisheries Society of the British Isle
Caracterização de compostos nutricionais e antinutricionais em plantas alimenticias não convencionais (PANC) utilizadas na gastronômia amazônica.
No full textIdentificação De Culturas De Basidiomicetos De Interesse Biotecnológicoda Coleção De Cultura De Microrganismos De Interesse Agrossilvicultural/Inpa.
No full textStudy of the reproductive biology of an Amazonian Heterotaxis (Orchidaceae) demonstrates the collection of resin-like material by stingless bees
No full textTropical and subtropical plants provide to pollinators a range of nutritive and non-nutritive materials as alternative to pollen and nectar, including resins, which are gathered by females of several groups of social and solitary bees. Although resin-like material has previously been recorded in Maxillariinae, these investigations generally did not present data relating to pollinators. In fact, the collection of resins has never been recorded elsewhere in orchids. The aim of this paper was to provide a detailed study of the reproductive biology of an Amazonian Heterotaxis, H. superflua, based on records of flowering phenology, floral morphology, pollinator behavior and breeding system. Heterotaxis superflua offers resin-like material to pollinators and is pollinated by a single species of stingless bee. The resin is a heterogeneous material rich in mucilage, starch and sugars, while lipoidal substances occur as small droplets. Chemical analyses confirm the presence of sugar, which explain the presence of reducing sugars and mucilage detected in the histochemical investigations. Our data also showed the Heterotaxis is self-compatible and pollinator dependent. This study demonstrates for the first time the collection of resin-like material in orchids. The gathering of resin is frequently associated with the nest construction, since this material is considered to be a water-repellent and has anti-pathogen chemical properties. Despite offering of a floral reward, fruit set under natural conditions is lower than for experimental pollinations, suggesting limited pollen flow within the population. © 2019, Springer-Verlag GmbH Austria, part of Springer Nature
Vertical profiles of Ozone concentration collected by an Unmanned Aerial Vehicle and the mixing of the Nighttime Boundary Layer over an Amazonian Urban Area
No full textThe nighttime boundary layer was studied in an urban area surrounded by tropical forest by use of a copter-type unmanned aerial vehicle (UAV) in central Amazonia during the wet season. Fifty-seven vertical profiles of ozone concentration, potential temperature, and specific humidity were collected from surface to 500 m above ground level (a.g.l.) at high vertical and temporal resolutions by use of embedded sensors on the UAV. Abrupt changes in ozone concentration with altitude served as a proxy of nighttime boundary layer (NBL) height for the case of a normal, undisturbed, stratified nighttime atmosphere, corresponding to 40% of the cases. The median height of the boundary layer was 300 m. A turbulent mixing NBL constituted 28% of the profiles, while the median height of the boundary layer was 290 m. The remaining 32% of profiles corresponded to complex atmospheres without clear boundary layer heights. The occurrence of the three different cases correlated well with relative cloud cover. The results show that the standard nighttime model widely implemented in chemical transport models holds just 40% of the time, suggesting new challenges in modeling of regional nighttime chemistry. The boundary layer heights were also somewhat higher than observed previously over forested and pasture areas in Amazonia, indicating the important effect of the urban heat island. © 2019 by the authors