Repositório RCAAP

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Deciduous dry forests are characterized by both seasonal climate and great leaf fall of the arboreus elements. They are distributed throughout tropical regions and within Triângulo Mineiro region they can be found in uphill turned around rivers. Currently, those forests are in a critical conservation status. Deciduous dry forests are the most threatened of all major tropical forests types. Despite their conservation status, ecological studies about these formations are few yet. The present study aims to research the vegetation structure and soils characteristics of two deciduous forests (Funil I and Funil II) located within Araguari river s valley (Minas Gerais State). For the phytossociology survey sixty 10 x 20 m plots were laid out in both areas. All the trees with a minimum circumference of 15 cm at 1.30 m upper ground were sampled. Composite soils samples were collected at a deep of 0-20cm for 20 plots in both forests. For each soil sample was analyzed pH, C, N, Ca, Mg, K, P, Al, Mn, Fe, thick sand, fine sand, silt and clay available. Canonical correspondence analysis (CCA) was used to check relationships between the distribution of the most abundant species and soil caracters. 2,034 individuals was found in Funil I. They are distributed in 64 species, 49 genera and 32 families. In Funil II was found 1,125 trees distributed in 46 species, 39 genera and 22 families. Shannon index calculed was 2.76 nat/ind. to Funil I and 2.59 nat/ind. to Funil II. Pielou evenness index was equal to both environments (J =0.66). Myracrodruon urundeuva, Myrsine umbellata, Myrcia rostrata and Campomanesia velutina were the most important species of Funil I. In Funil II, M. urundeuva, Tabebuia roseo alba, Anadenanthera colubrina and C. velutina were the most important species. Chemical analysis of both forest s soils showed a high chemical similarity. The pH values of both soils Funil I and II indicated a moderate acid. Soil nutrients available was similar in both areas, except for P. In contrast with similarity chemical was found a high fisical difference between Funil I and Funil II soils. Thick sand contents in Funil II was bigger than Funil I. On the other hand, fine sand, silt and clay available in Funil I was bigger than Funil II. In the correspondence canonical analysis it was evidenced the most of the species is distributed throughout environment in both forests, just altering your abundances. Short gradients suggest that one or several environmental variables not analyzed at present work can be interfering in the species distribution. Therefore, for a best knowledge about the relationship between species distribution and environmental variables it is necessary more studies in different areas because just with a lot of replications we can understand and arrive to a model that really explain the distribution species within environment.

Mestre em Ecologia e Conservação de Recursos Naturais

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

The social behavior is rare among the arachnids. The most complex forms are found in the cooperative spiders, characterized by generation overlap, communal nests, food sharing and cooperative parental care. The two unique social pseudoscorpion species are found in South America. These species present a very similar social structure observed in the cooperative spiders, denominated "non-territorial permanent sociality". The present study investigated the natural history and the social behavior of Paratemnoides nidificator, a very common social Atemnidae in the Brazilian Savannah (Cerrado), at field and laboratory, over four years. This pseudoescorpião constitutes large family colonies, characterized by cooperative parental care extended until that the nymphs reach the adult phase, which can culminate in matriphagy. P. nidificator is a sit-and-wait generalist predator, capable to attack and subdue cooperatively preys sixty times heavier than a single individual. The dispersion in this species occurs by two ways: phoresy and colony fission. The Paratemnoides colonies present etarian and sexual division of work, in which individuals of different sex or stage can specialize in specific tasks colony maintenance. This is the first wide study about the natural history and behavior of a social pseudoscorpion. All these information, together, allow a wide comparison of the pseudoscorpions and spiders social organization.

Studies focusing syntopic species help to understand how they partition resources and coexist. The objective of this work was to describe the social system, habitat use and diet of the hoary fox (Pseudalopex vetulus) and the crab-eating fox (Cerdocyon thous), in an area of cattle farms in Central Brazil. It is also reported a confrontation between the two species, observed during a study on the behavioral repertory of the hoary fox. Social system and habitat use were studied by direct observation of foxes in the field and diet, through scat analysis. Crab-eating foxes were found in pairs in 34 (59%) of 58 encounters and hoary foxes were solitary in 58 (84.0%) of 69 encounters, with no seasonal variation in the group size of both species. During one encounter of a crab-eating fox couple, the male vocalized to call the female that had remained behind. Hoary foxes were sighted in grazed pasture in a higher proportion (84%) than crab-eating foxes (67%) and they were never found in forest neither in swamp. Besides, both species were rarely seen together, and the only encounter registered ended in a conflict, with the crab-eating fox driving the hoary fox out. Twenty-seven taxa were identified in the diet of the two canids, with the crab-eating fox (n = 32 scats) consumed fruits, insects (mainly Orthoptera and Coleoptera) and vertebrates (most Cricetidae and Squamata) and the hoary fox (n = 23 scats) ate primarily termites (Isoptera). Results indicate that crab-eating fox couples keep more tight bonds than hoary fox couples. The coexistence of both species may be related to the detected differences in habitat use and diet.

This study investigated the hole of size and corporal symmetry in the sexual selection of D. maurus, an insect-plague responsible for serious economic injuries in cotton cultures. Aspects of the courtship and mating behavior of this species were also described. In order to obtain the morphometric measurements, 30 single males and 30 couples were used for slide confection. For corporal biomass assessment, 40 single males and 90 couples were weighted. Moreover, 50 single females and 50 single males were used for the observation of the courtship and mating behavior. The morphometric measurements achieved were simplified by the Principal Component Analysis in order to attain a multivaried index of size. The corporal asymmetry was estimated by calculating an index of Fluctuating Asymmetry (FA). The morphometric measurements, the weight and the indexes of size and FA were compared between paired and single males by using the t test. The relationship between male and female sizes was verified by using the simple linear regression. In all mating attempts male-female struggles were observed and the courtship was always performed by males. The t test indicated significant differences in the individuals weight, in the length of the 1° fore tarsus and in the FA index of the hind tibia between paired and single males. There is a relationship between the couple s weights. Thus, females of D. maurus choose indirectly the male based on morphometric and behavioral characteristics that allow the males to be good manipulators. Larger males with more symmetrical hind tibias and longer fore tarsus are more successful in sexual selection.

The cerrado covers about 23% of the Brazilian territory, and 70% of the cerrado area is stricto sensu physiognomy. To promote a better understanding of its physiognomic the cerrado study is of vital importance. With the objective to analyze and to compare two tree area of cerrado sensu stricto (brazilian s savanna) in the Reserva Ecológica do Clube Caça e Pesca Itororó had been studied, in each area, five parcels (20x50 m) totalizing one hectare of Cerrado sensu stricto, showing to all the individuals with perimeter the 30 cm of the ground equal or the top 15 cm (also the dead individuals). 1,625 individuals had been showed in area I, of which, 93 died in foot, creature distributed in 54 species, 39 sorts and 28 families. In area II 839 individuals, 66 died, creature distributed in 43 species, 33 sorts and 23 families. Totalizing in both the areas (1 ha) 58 species. Of these, 39 (67.24%) are common to the two areas, 15 (25.86%) exclusive ones of area I and 04 (6.90%) of area II. The data show that the majority of the individuals concentrates in the 3,5 m height, with some emergent species, that the 12 m. Area I presented 48.36% more individuals that area II, and area II presented a bigger mortality (7.9% of the total of individuals) that the I (5.7%). How much to the sprouts, in area I only 4.25% of the individuals they had presented sprouts again, distributed in 23 species; while area II 54% of the individuals, distributed in 38 species had had sprouts again. The data show that the protection against the fire increases the density of individuals, the vertical and horizontal structure of the community, beyond favoring the establishment of sensible species as Ouratea hexasperma, Roupala montana, Caryocar brasiliense, Acosmium subelegans, Plenckia populnea, Diospyros hispida, Erythroxylum suberosum, Machaerium acutifolium and Eugenia punicifolia what it contributes for the increase of the diversity of the community. Annona crassiflora, Eriotheca gracilipes, Dimorphandra mollis, Ouratea spectabilis, Pouteria ramiflora, Styrax ferrugineus and Qualea grandiflora had revealed indifferent to the frequency of forest fires; already Aspidosperma tomentosum, Piptocarpha rotundifolia, Erythroxylum tortuosum, Pterodon pubescens, Stryphnodendron adstringens, Stryphnodendron polyphyllum and Vochysia rufa are more resistant species to the forest fires and seem to benefit with this riot to be established.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Predator-prey interactions play a key role in the evolution of adaptive mechanisms and aggressive postures in different animal groups. From this, organisms with colors and behaviors that reduce the risk of detection by natural enemies have a huge selective advantage over those who do not have this attribute. Species with maternal care can maximize their reproductive effort protecting eggs and offspring. In addition, aggressive behaviors against predators and other natural enemies appear to be essential to avoid the enemies attacks and increase offspring survivorship . Thus, in this study we aim to describe web building patterns during maternal behavior, and the influence of previous investment in reproduction and spider size on aggressive behavioral responses against artificial stimuli simulating attacks of predators. We also examined, from the perspective of view of natural enemies, if the colors of spiders and egg sacs are similar to each other and to the branches in which the webs are attached . We observed that females build modified webs during the period of egg sac protection, in which they are unable to capture prey and remain in a cryptic posture, aligned with their tubular egg sacs. Spiders carrying egg sacs showed aggressive responses to artificial stimuli and spiders without egg sacs always ran away or avoided the source of disturbance. Aggressive responses, however, were independent of clutch size and female body size. . Color analyzes showed that Hymenoptera and birds can not differentiate the colors of spiders and egg sacs, and of spiders and branches as well, showing the importance of color in decreasing detection from this specie.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Fundação de Amparo a Pesquisa do Estado de Minas Gerais