Quinolizidine alkaloids in Ormosia arborea seeds inhibit predation but not hoarding by agoutis (Dasyprocta leporina)

Quinolizidine alkaloids (QAs) are secondary compounds found in seeds of many species of plants, possibly protecting them against pathogens and seed predators. QAs were isolated from Ormosia arborea seeds and bioassayed against red-rumped agoutis (Dasyprocta leporina, Rodentia: Caviomorpha) to verify if they inhibit seed predation and food hoarding (seed dispersal). Three treatments were used: (1) seeds of O. arborea, (2) palatable seeds of Mimusops coriacea (Sapotaceae) treated with MeOH, and (3) seeds of M. coriacea treated with QAs dissolved in MeOH in similar concentration to that present in O. arborea. Palatable seeds were significantly more preyed upon than seeds treated with QAs and Ormosia seeds, but QAs did not influence hoarding behavior. QAs in O. arborea may have a strong effect in avoiding seed predation by rodents, without reducing dispersal.

Testing the quick meal hypothesis: the effect of pulp on hoarding and seed predation of Hymenaea courbaril by red-rumped agoutis (Dasyprocta leporina)

Red-rumped agoutis (Dasyprocta leporina) are important seed dispersers/predators of Neotropical large-seeded plants. Several species of seeds cached by agoutis have an edible reward, in contrast to temperate rodent-dispersed diaspores. The quick meal hypothesis states that the presence of a reward such as edible pulp will enhance the efficiency of rodents as seed disperses by satiating the animal and, consequently, reducing seed predation and enhancing hoarding. In this study, this hypothesis was tested using as the reference system the pulp and seeds of Hymenaea courbaril. Seeds with and without pulp were offered to agoutis and the behaviour of each individual was recorded. Since the probability of predation and hoarding were complementary, we used the probability of predation. The proportion of agoutis that preyed on at least one seed was similar for seeds with (42.8% of individuals) and without (40.0% of individuals) pulp. In agoutis that preyed upon at least one seed, the probability that they killed a seed did not differ between seeds with (0.17 +/- 0.03) and without (0.20 +/- 0.08) pulp. Hence, these results do not support the 'quick meal hypothesis'.

The role of seed mass on the caching decision by agoutis, Dasyprocta leporina (Rodentia: Agoutidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ecologia da cutia Dasyprocta leporina (Linnaeus, 1758) em um fragmento florestal urbano em Campinas - SP (Rodentia: Dasyproctidae)

Pós-graduação em Ciências Biológicas (Zoologia) - IBRC

Padrão de atividade da jaguatirica (Leopardus pardalis), cutia (Dasyprocta leporina) e paca (Cuniculus paca) no sul da Amazônia brasileira

Não disponível

The subplacenta of the red-rumped agouti (Dasyprocta leporina L)

Background: Hystricognath rodents have a lobed placenta, comprising labyrinthine exchange areas and interlobular trophoblast. These correspond to the labyrinthine and spongy zones of other rodent placentae. Beneath them, however, is a structure unique to hystricognath rodents called the subplacenta. We here describe the subplacenta of the red-rumped agouti and examine the possible functional correlates of this structure. Methods: Placentae were collected from early in midgestation to near term of pregnancy and examined by standard histological techniques, immunohistochemistry and transmission electron microscopy. In addition, to study the microvasculature of the subplacenta, vessel casts were inspected by scanning electron microscopy. Results: In the subplacenta, lamellae of connective tissue support a layer of mononuclear cytotrophoblast cells. Beneath this is found syncytiotrophoblast. Clusters of multinuclear giant cells occur in the transition zone between the subplacenta and decidua. There are prominent intercellular spaces between the cytotrophoblast cells. The basal membrane of these cells is often close to fetal blood vessels. The syncytiotrophoblast surrounds an extensive system of lacunae. Microvilli project into these lacunae from the plasma membrane of the syncytiotrophoblast. The syncytial cytoplasm contains electron-dense granules. This is probably the amylase-resistant PAS-positive material identified by histochemistry. The subplacenta is supplied entirely from the fetal circulation. Within it the vessels pursue a tortuous course with sinusoidal dilatations and constrictions. Conclusion: The functions that have been attributed to the subplacenta include hormone production. Our findings are consistent with this interpretation, but suggest that hormone secretion is directed towards the fetal circulation rather than the maternal tissues.

Obtenção e conservação de espermatozoides de cutia (Dasyprocta leporina Linneaus, 1753) do semiárido brasileiro

The general objective of this thesis was to stablish protocols to obtain and conserve agouti (Dasyprocta leporina) sperm bred in captivity in the Brazilian semi-arid, aiming its sustainable production. The thesis was divided in three experiments. In the first one, we studied the influence of the interaction between two probes (quadratics and sine waves) and two stimulation protocols (continuous and in series) on the agouti sperm collection by electroejaculation efficiency. The most efficient interaction on this obtainment was the one with probes with rings associated with stimuli in series (4/7; 57%, P<0.05). In the second experiment we compared the cryoprotectant effects of different substances (glycerol, ethyleneglycol, dimethylsulfoxide, dimethylformamide) on epididymis sperm cryopreservation. The highest values on motility (39.5±4.6%), vigor (2.9±0.2) and membrane integrity (30.6±4.5%) were observed on the samples cryopreserved using glycerol when compared to those with ethyleneglycol and dimethylformamide, but there was no difference (P>0.05) when compared to the samples cryopreserved with dimethylsulfoxide. At last, we studied the effects of the methods to obtain sperm (electroejaculation vs epididymal collection) on post thawing sperm quality. The samples obtained by epididymal retrograde flushing showed values for motility of 25.0±10.9% and vigor 2.4±0.8, and those obtained by electroejaculation had 31.2±14.2% of motility and vigor of 2.2±0.7, however, without statistical difference (P>0.05), which shows the possibility to successfully use the epididymal sperm cryopreservation protocol on agouti ejaculated sperm. In conclusion, significant advances on obtainment and processing of agouti sperm were made, allowing the establishment of germplasm banks from sperm samples obtained from the epididymis or by electroejaculation.

Os mamíferos de médio porte e suas respostas à fatores ambientais, físicos e antrópicos, sobre diferentes perspectivas, no Parque Estadual da Ilha Grande RJ

A variação espacial das características bióticas e abióticas de um ambiente influencia na distribuição de médios mamíferos, sobre diferentes escalas. O Parque Estadual da Ilha Grande (PEIG) possui ambiente bastante heterogêneo e abriga uma mastofauna de médio porte ainda pouco estudada. O objetivo deste estudo é avaliar o efeito das variáveis físicas, do micro-habitat, da estrutura da vegetação e dos impactos antrópicos na comunidade e nas espécies de mamíferos de médio porte do PEIG. O registro das espécies foi por armadilhas fotográficas e as variáveis do ambiente mensuradas por diferentes métodos nas 49 estações de câmeras. Com os resultados desse estudo inferimos que a riqueza de nove espécies de mamíferos de médio porte nativos, corresponde a esperada para um ambiente insular. As espécies mais abundantes foram Dasyprocta leporina, Agouti paca, Dasypus novemcinctus e Didelphis aurita, a mais rara foi o Leopardus wiedii. A composição da mastofauna difere entre as vertentes norte e sul da Ilha Grande (ANOVA, p=0,01). O maior número de indivíduos foi registrado na vertente sul, onde há o efeito da variação da altitude, menor variação do micro-habitat e menor densidade da população humana. Contudo a estrutura da vegetação não difere entre as vertentes e não afeta as espécies mais abundantes. Essas espécies são sensíveis às variáveis físicas. Há impacto da densidade populacional nas vilas sobre a composição e abundância das espécies de médios mamíferos, apesar da caça não ter efeito nas áreas amostradas. Os mamíferos de médio porte são sensíveis às variáveis de maior escala e podem ter sua comunidade estruturada em função do impacto antrópico. A complexidade de habitat e o controle de habitantes no PEIG são importante para manter a comunidade de mamíferos de médio porte.

Seed dispersal and predation in the endemic Atlantic rainforest palm Astrocaryum aculeatissimum across a gradient of seed disperser abundance

Tropical forests have been subject to intense hunting of medium and large frugivores that are important in dispersing large-seeded species. It has been hypothesized that in areas with extinction or low abundance of medium and large-bodied animals the density of small rodents may increase. Therefore, this increment in the density of small rodents may compensate for the absence or low abundance of medium and large frugivores on seed removal and seed dispersal. Here, we fill up this gap in the literature by determining if seed removal, seed dispersal, and seed predation by small rodents (spiny rats, Trinomys inheringi and squirrels, Sciurus ingrami) are maintained in defaunated areas. We accessed seed removal, seed dispersal, seed predation, and seedling recruitment of an endemic Atlantic rainforest palm, Astrocaryum aculeatissimum, in a gradient of abundance of agoutis. We found that seed removal, scatter hoarding, and seed predation increase with the abundance of agoutis. In contrast, the proportion of dispersed but non-cached seeds decreased with the abundance of agoutis. We did not find any effect of the abundance of agoutis on seed dispersal distance, but we did find a positive trend on the density of seedlings. We concluded that small rodents do not compensate the low abundance of agoutis on seed removal, scatter hoarding, and seed predation of this palm tree. Moreover, areas in which agoutis are already extinct did not present any seed removal or scatter hoarding, not even by small rodents. This study emphasizes both the importance of agoutis in dispersing seeds of A. aculeatissimum and the collapse in seed dispersal of this palm in areas where agoutis are already extinct.

Are tortoises important seed dispersers in Amazonian forests?

According to most studies on seed dispersal in tropical forests, mammals and birds are considered the main dispersal agents and the role played by other animal groups remains poorly explored. We investigate qualitative and quantitative components of the role played by the tortoise Chelonoidis denticulata in seed dispersal in southeastern Amazon, and the influence of seasonal variation in tortoise movement patterns on resulting seed shadows. Seed shadows produced by this tortoise were estimated by combining information on seed passage times through their digestive tract, which varied from 3 to 17 days, with a robust dataset on movements obtained from 18 adult C. denticulata monitored with radio transmitters and spoon-and-line tracking devices. A total of 4,206 seeds were found in 94 collected feces, belonging to 50 seed morphotypes of, at least, 25 plant genera. Very low rates of damage to the external structure of the ingested seeds were observed. Additionally, results of germination trials suggested that passage of seeds through C. denticulata`s digestive tract does not seem to negatively affect seed germination. The estimated seed shadows are likely to contribute significantly to the dispersal of seeds away from parent plants. During the dry season seeds were dispersed, on average, 174.1 m away from the location of fruit ingestion; during the rainy season, this mean dispersal distance increased to 276.7 m. Our results suggest that C. denticulata plays an important role in seed dispersal in Amazonian forests and highlight the influence of seasonal changes in movements on the resulting seed shadows.

Habitat patch size modulates terrestrial mammal activity patterns in Amazonian forest fragments

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Development of the inverted visceral yolk sac in three species of caviids (rodentia, caviomorpha, caviidae)

Guinea pig related rodents possess numerous derived placental characters. We attempt to identify diversity within the visceral yolk sac and its association with the chorioallantoic placenta in three species of caviids, two of them possessing a capsule formed by the decidua that covers the chorioallantoic placenta. The results verify that in early pregnancy all three species have in inverted yolk sac placenta. In advanced pregnancy the species differ: Galea spixii, as representative without a capsule, bear a yolk sac in apposition to the chorioallantoic placenta with signs of exchange activity until term. Galea is similar to other caviomorphs in this respect. In Dasyprocta leporina and Cuniculus paca, the representatives possessing a capsule, the yolk sac endoderm lacks signs of substance exchange. Evidently, the presence of a capsule prevents such ail interaction. The variations established here must be considered if animal models for human placentation are required which have restricted access to the chorioallantoic placenta from the outside. (C) 2008 Elsevier Ltd. All rights reserved.

O uso da fauna cinegética e o consumo de proteína animal em comunidades rurais na Amazônia oriental: Reserva Extrativista Tapajós/Arapiuns Pará - Brasil

A caça e a pesca são exemplos clássicos de exploração de recursos naturais pelo homem, uma vez que estas atividades vêm sendo desenvolvidas desde a pré-história e, para algumas comunidades, continua sendo fonte de alimento tão importante quanto era para nossos antepassados. A pesca e outros produtos oriundos do extrativismo vegetal têm sido alvo constante de pesquisas para atender o mercado industrial, em detrimento dos estudos de etnoconservação. Em conseqüência desse desinteresse institucional e de outros fatores políticos intrínsecos, pouco se sabe sobre a biologia, a ecologia, a etologia e principalmente sobre a intensidade de exploração da fauna cinegética nos trópicos. Há uma grande lacuna sobre estudos que tratam da dieta de populações tradicionais na Amazônia, sobretudo aqueles que discorrem sobre a importância econômica e nutricional da atividade de caça e sua correlação com a conservação da vida silvestre. Este Estudo de Caso orientou-se para realizar a caracterização da fauna cinegética explorada por famílias extrativistas nas comunidades Aminã e Solimões na Reserva Extrativista do Tapajós/Arapiuns - PA, nas duas estações do ano (chuva e seca), além de revelar parâmetros nutricionais da atividade de caça na dieta protéica daquelas famílias. Os dados de abundância relativa (biomassa) para as espécies registrada nas duas comunidades estudadas mostram que Dasyprocta leporina (cutia) se revelou como a espécie mais pressionada. Quando comparados os Índice de Biomassa (IB) entre as fontes de proteínas animal e entre as comunidades estudadas, concluiu-se que a carne de caça, apesar de ser menos freqüente em termos de dias de consumo em relação ao pescado, as refeições realizadas com carne de caça são mais fartas do que as refeições realizadas com peixe. Além disso, com relação ao Índice de Proteína (IP), quando comparado entre fontes critérios e parâmetros para a implementação de projetos de manejo integrado de fauna em ocupações humanas.

Conservação de material genético de espécies silvestres do bioma caatinga utilizando a manipulação oócitos inclusos em folículos ovarianos pré antrais (MOIFOPA)

The objective of the present thesis was to use the manipulation of oocytes enclosed in preantral follicles (MOEPF) as a tool for the female gametes rescue and optimization, from wild species of Caatinga biome. The thesis was divided into 4 experiments. At first experiment, it was performed the estimative and description of the agouti (Dasyprocta leporina) preantral follicles (PF) histologic and ultrastructural features, in which it was estimated 4419.8 ± 532.26 and 5397.52 ± 574.91 follicles for the right and left ovary, respectively, and the majority (86,63%) belonged to the primordial follicles category (P<0.05). Most of the population consists of morphologically normal follicles (70.78%), presenting a large and central nuclei and uniform cytoplasm. At ultrastructural evaluation it was verified the presence of a great number of round mitochondrias associated to lipid droplets. In the second experiment, it was performed the estimative and description of yellow-toothed cavies (Galea spixii) PF characteristics, also, the evaluation of the effect of solid surface vitrification (SSV) on the in situ PF morphology. The total of 416.0 ± 342.8 PF was estimated for the ovary pair and the presence of a large quantity of primary follicles (P<0.05) was evidenced. Most of the PF was morphologically normal (94.6%), in which the oocyte nuclei presented condensed granules of heterochromatin. Round or elongated shaped mitochondria constituted the most abundant organelles. In regard of the SSV, the protocol using the dimethylsulfoxide (DMSO) 3M possibility the preservation of 69.5% of morphologically normal PF, which was evidenced by the light and transmission electronic microscopy. At third experiment, the evaluation of the SSV procedure on the morphology and viability in situ PF form collared peccaries (Pecari tajacu) was performed. No differences were observed among treatments, in which the use of DMSO, ethylene glycol (EG) and dimethylformamide (DMF) as cryoprotectants, regardless its concentration, promoted the morphology preservation of much than 70% of PF. Concerning the PF viability, the DMSO and EG promoted the best preservation. The fourth experiment aimed to evaluate the effect of α MEM+ or TCM199 associated or not to 50 ng of FSHr on the morphology, activation and growth of collared peccaries PF, in vitro cultured (IVC) during 1 or 7 days and the effect on the extracellular matrix (ECM). After 7 days of IVC only the use of TCM199/FSH maintained the proportion of intact PF, similar to day 1(63.2%), however, no differences were observed among treatments (P>0.05). Also, an improvement of the proportion of intact growing PF was verified (P>0.05). By the Ag-NOR analysis it was observed that only the treatment using TCM199/FSH promoted the maintenance of cell proliferation similar to day 1 (P>0.05). The picrosirius red stain revealed that ECM remained intact in all treatments (P>0.05). Thus, as the general conclusion, the use of MOEPF in the refereed species allowed the knowledge of aspects related to its reproductive morphology and physiology, enabling the germplasm conservation, with the possibility of germplasm bank formation, as the elucidation of mechanisms related to the PF survive and in vitro development.