Lucélia Nobre Carvalho

Ecology of neotropical mistletoes: an important canopy-dwelling component of Brazilian ecosystems

Ervas-de-passarinho tem sim sido regularmente estudadas em paises temperados por afetar negativamente especies cultivadas e florestas manejadas. Em comparacao com ambientes temperados pouco se conhece sobre a ecologia das ervas-de-passarinho neotropicais. Desta forma, e necessario maior conhecimento sobre o grupo porque sao importantes elementos de comunidades vegetais, atuando como recurso-chave para polinizadores, dispersores de sementes e herbivoros. Atraves de uma combinacao de trabalhos classicos ja publicados com evidencias empiricas recentes, nos apresentamos padroes emergentes da interacao entre ervas-de-passarinho com os organismos associados e questionamentos para estudos adicionais. Existe um crescente interesse neste grupo no Brasil. E embora existam informacoes sobre dispersao de sementes, estudos sobre biologia reprodutiva sao raros e representam um campo a ser explorado. O conhecimento da biologia basica das ervas-de-passarinho sera relevante para modelar sua distribuicao espacial usando uma abordagem metapopulacional ou epidemiologica. Nesta revisao nos sumarizamos os principais estudos conduzidos na regiao Neotropical para fornecer um panorama atual das pesquisas desenvolvidas, bem como novas ideias para futuras investigacoes, especialmente no Brasil.

Color changing and behavioral context in the Amazonian Dwarf Cichlid Apistogramma hippolytae (Perciformes)

Animal coloration has many functions, and fishes are noted among vertebrates for presenting a wide variety of color patterns. Although in marine fishes the relationship between body coloration and behavioral context is well documented, there’s not much information about freshwater fishes. Here we describe color patterns displayed by the dwarf cichlid Apistogramma hippolytae and suggest that these patterns are dependent on different social and behavioral settings. Field observations were conducted underwater in a pond in Central Amazonia, Brazil. We recorded six body coloration patterns related to seven different kinds of behavioral activities: foraging, resting, reproductive and agonistic displays, aggression (attacking and fleeing) and parental care. Changes in coloration occur rapidly and take only a few seconds. Females on parental care exhibited a unique pattern that are more persistent and probably manifests more slowly. In the shallow and clear waters of the natural environment of this dwarf cichlid, color communication seems to constitute an efficient way to display information about individual mood, social status and reproductive readiness, contributing to minimize loss of energy in unnecessary interactions. Coloracao animal tem diferentes funcoes, e os peixes se destacam entre os vertebrados por apresentarem uma grande diversidade de padroes de cores. Embora se conheca relativamente bem a relacao entre coloracao e contexto comportamental para peixes marinhos, pouco se sabe para os peixes de agua doce. Nos descrevemos os padroes de coloracao de um ciclideo amazonico, Apistogramma hippolytae, e sugerimos como esses padroes sao dependentes das caracteristicas sociais e comportamentais. Realizamos observacoes subaquaticas utilizando mergulho livre em campo durante o dia em uma lagoa na Amazonia Central. Nos caracterizamos seis padroes de coloracao associados a sete comportamentos diferentes: alimentacao, repouso, displays sexual e agonistico, agressao (ataque e fuga) e cuidado parental. As mudancas de coloracao levam apenas alguns segundos. Femeas em cuidado parental exibem um padrao exclusivo, cuja mudanca e mais lenta. No ambiente natural desse ciclideo, locais rasos com aguas claras, a comunicacao por coloracao pode ser um sistema eficiente de comunicar o estado motivacional individual, status social e disposicao para reproducao, possivelmente contribuindo para minimizar a perda de energia com interacoes desnecessarias.

Centromochlus meridionalis, a new catfish species from the southern Amazonian limits, Mato Grosso State, Brazil (Siluriformes: Auchenipteridae)

Centromochlus actually comprises eleven species, being the most problematic genus among the Centromochlinae, including morphologically heterogeneous taxa. The Centromochlus species have a wide distributional area on northern South America. Centromochlus meridionalis, new species, is described from headwaters of rio Teles Pires, contributor of rio Tapajos, Mato Grosso State, Brazil, and represents one of the southernmost records of a centromochlin catfish for Meridional Amazon rivers. Centromochlus meridionalis is promptly distinguished from its congeners by the small orbital diameter (relative to head length), and also by the combination of absence of first nuchal plate, anterior margin of dorsal-fin spine smooth, six branched rays in anal fin, seven pairs of ribs and 34 vertebrae. They are small sized catfishes with adults between 33 to 61 mm in standard length. The modified male anal fin is conspicuous, with the third unbranched ray enlarged, about twice the width of first unbranched ray. The new species inhabits a region strongly endangered by environmental changes due to expansion of agropecuary activities on Brazilian Amazon, which include this species in an uncertain situation regarding the conservation status of its natural population.

Second floor, please: the fish fauna of floating litter banks in Amazonian streams and rivers

Floating litter banks are an ephemeral habitat consisting of branches, twigs, flowers, seeds, and fruits that are trapped on the stream water surface by a variety of retention mechanisms. These heterogeneous materials form a deep layer of dead plant matter that is colonized by a variety of organisms, including fish that forage on the aquatic macroinvertebrates found in this unique habitat. In this study, we aimed to characterize which fish species occupy the floating litter banks and their trophic characteristics, as well as determine if fish assemblage composition and species richness can be predicted by the size of the floating litter banks. Fish sampling was conducted in five rivers located in the Amazon basin. Of the 31 floating litter banks sampled that contained fish, 455 individuals were recorded and were distributed within 40 species, 15 families and five orders. Siluriformes were the most representative order among the samples and contained the largest number of families and species. The fish fauna sampled was mainly composed of carnivorous species that are typically found in submerged litter banks of Amazonian streams. The fish assemblage composition in the kinon can be predicted by the volume of the floating litter banks using both presence/absence and abundance data, but not its species richness. In conclusion, kinon banks harbor a rich fish assemblage that utilizes this habitat for shelter and feeding, and may function as a refuge for the fishes during the peak of the flooding season.

Nature-Based Tourism Elicits a Phenotypic Shift in the Coping Abilities of Fish

Nature-based tourism is gaining extensive popularity, increasing the intensity and frequency of human-wildlife contacts. As a consequence, behavioral and physiological alterations were observed in most exposed animals. However, while the majority of these studies investigated the effects of punctual exposure to tourists, the consequences of constant exposition to humans in the wild remains overlooked. This is an important gap considering the exponential interest for recreational outdoor activities. To infer long-term effects of intensive tourism, we capitalized on Odontostilbe pequira, a short-lived sedentary Tetra fish who spends its life close to humans, on which it feeds on dead skin. Hence, those fish are constantly exposed to tourists throughout their lifecycle. Here we provide an integrated picture of the whole phenomenon by investigating, for the first time, the expression of genes involved in stress response and neurogenesis, as well as behavioral and hormonal responses of animals consistently exposed to tourists. Gene expression of the mineralocorticoid (and cortisol) receptor (mr) and the neurogenic differentiation factor (NeuroD) were significantly higher in fish sampled in the touristic zone compared to those sampled in the control zone. Additionally, after a simulated stress in artificial and controlled conditions, those fish previously exposed to visitors produced more cortisol and presented increased behavioral signs of stress compared to their non-exposed conspecifics. Overall, nature-based tourism appeared to shift selection pressures, favoring a sensitive phenotype that does not thrive under natural conditions. The ecological implications of this change in coping style remain, nevertheless, an open question.

Assessment of mercury contamination in Brycon falcatus (Characiformes: Bryconidae) and human health risk by consumption of this fish from the Teles Pires River, Southern Amazonia

Brycon falcatus is one of the most highly consumed species of fish within the region in the Teles Pires basin, and has great commercial importance in sport and professional artisanal fishing. The objective of this study was to analyze the presence and concentration of total mercury (THg) in the muscle, liver and gills of B. falcatus, and calculate the risk to human health of THg contamination from ingestion of the fish. THg concentrations were similar in the liver (0.076 mg kg-1) and muscle (0.052 mg kg-1), and higher than in the gills (0.009 mg kg-1). The levels of HgT present in B. falcatus tissues did not influence weight gain and nutritional status. Based on the condition factor, weight and length ratio and hepatosomatic index, it seems that the concentrations of THg did not influence the health and well-being of B. falcatus collected in the Teles Pires River basin. THg concentrations in the muscle of B. falcatus are below the limit recommended by the World Health Organization for people who consume until 250 g of fish per week. The risk of deleterious effects on human health may exist if there is a greater consumption of B. falcatus such as 340 g/day, that is the mean of fish consumption by indigenous and riverine.