Repositório RCAAP

The aim of this study was to compare ant community structure between the savannas of Brazil and Australia. The study was conducted in woodland savanna areas nearby Darwin, in northern Australia, and Uberlândia and Caldas Novas in central Brazil. The sampling design consisted of eight 400 m line transects, four in each continent, with eight pitfall traps and four baits located on and around each of 20 trees evenly spaced along each transect. Ant richness and species turnover were compared at three spatial scales: pitfalls associated with a tree, trees within a transect, and transects within a savanna. The composition of the Australian and Brazilian savanna ant faunas was broadly similar at the sub-family level, despite the very low proportion of shared genera and species. Overall ant abundance was almost three times higher in Australia than in Brazil, both on the ground and on vegetation, but overall species richness was higher in Brazil (150 species) than in Australia (93). Species richness was similar at very small (pitfall trap) scales, but was increasingly higher in Brazil with increasing spatial scale. In the Australian savanna and, to a lower extent, in the Brazilian savanna the ant assemblage from the trees was a nested subset of the ground ant assemblage. However, while in Australia there was a positive relationship between tree and ground ant abundance, but not for ant richness, the same relationship was found for ant richness, but not for ant abundance, in the Brazilian savanna. Interspecific competition was relatively more important for the ant community structure of the Australian savanna than for the Brazilian savannas, regardless of the nesting/foraging stratum. Also, interspecific competition was relatively more important in structuring soil than compared to the tree assemblages. Finally it was found that there were greater ant richness, abundance and dominance at nitrogen-rich baits than at carbohydrate-rich baits for both soil and tree ant assemblages. My study revealed scale-dependent differences in species richness and species turnover for savanna ant assemblages in Australia and Brazil. This further underlines the importance of biogeographical context when analyzing ant communities and also highlights the importance of processes acting at regional scales in determining species richness in ant communities. I also concluded that interspecific competition is an important force in structuring the savanna ant community but other factors such as evolutionary history, habitat preferences and stochastic events may also play an important role in the organization of the savanna ant community.

Despite being extremely abundant and diverse, ground-dwelling spiders are poorly known in Brazil. The present study, conducted between April 2005 and February 2007, investigates the composition, richness and diversity of ground-dwelling spiders, as well as the influence of seasonality on them and the structure of this community. It was carried out at the Panga Ecological Station in the State of Minas Gerais, southeastern Brazil. Three very distinct phytophysiognomies (campo cerrado, cerrado and cerradão) were sampled using pitfall traps during five days every two months. A total of 3,477 spiders of 112 species and 31 families were found. At least eight new species were found and one species, Trocantheria gomezi (Trochanteridae), was recorded for the first time in Brazil. All sites presented unique species compositions, richness and diversity. Increased abundance and richness were observed during the wet season. The peak of individuals was in October and April registered the lowest abundance. Furthermore, the first ecological data for Tenedos perfidus (Zodariidae), an endemic species of this Ecoregion, was presented. Between the eight guilds found, active hunters on the ground were the most abundant in the three habitat types, followed by web-builders and ambushers. The community structure vary between phytophysiognomies and between seasons. Abundance per guild was higher during wet season. The diversity among ground-dwelling spiders in Brazilian Savannas is very heterogeneous and pointed out the importance of conserving different habitat types for the maintenance of their biodiversity.

In entomophilous plants, the most frequent flower visitors are social and solitary bees. The relationship is mutualistic, as bees benefit from pollen and nectar, and plants have their pollination performed by bees. The study of the guilds of flower-visiting bees presents as results, among others, the understanding of the guild structure and the factors that interfere with this structure. Among these, the deforestation of natural areas, as in the Cerrado , has been considered as one of the main factors. Thus, a common Cerrado plant Matayba guianensis Aubl., (Sapindaceae) was chosen, with the goal of studying the structure of the guild of flower-visiting bees in this species. Other objectives were: to investigate whether the environmental differences among three Cerrado areas would have an influence on the structure of this guild and determine the flower visitors and probable pollinators of Matayba guianensis, besides bees. Three Cerrado sites were chosen in the city of Uberlândia, Minas Gerais, Brazil: the Panga Ecological Station (EEP), with 1,011.90 a; the Palma da Babilônia Farm (FPB), with 444.79 a and the Souza Cruz (SC) Property, with 70.43 a. The areas presented environmental differences evinced by the estimates of natural vegetation in the surroundings: 52.62 % for EEP, 32.94 % for FPB and 9.73 % for SC. Bees and other insects were collected on Matayba guianensis in two consecutive flowering periods, from October to December of 2005 and 2006. Matayba guianensis presented asynchrony in its phenological stages and predominance of staminate individuals (64,7%) in comparison to the estaminate/pistilate and only pistilate individuals, and was considered a generalist species regarding its flower visitors. In the first phase, 1516 bees were collected, belonging to five families of Apoidea and to 80 species. Analyzing these, we found 30% of dominant and 46.3% of rare species. In the second phase, 562 bees, belonging to 66 species, composed of 15.2 % of dominant ones and 56.1% of rare ones, were collected. Overall, 2078 bees, pertaining to 105 species, were collected. The Apidae family stood out in terms of number of species and individuals. The most abundant species was Apis mellifera, which represented 41.9 % and 32.7% of the bees collected in the first and second phases, respectively, followed by Scaptotrigona depilis. The visitation pattern of these species is not indicative of resource sharing. The structure of the guild, with many rare species and few abundant ones, as much as the richness and abundance of the families of Apoidea, was similar to other studies conducted in the Cerrado region. The collecting of bees in a single plant species was capable of representing, at least partially, the richness of bees in the Cerrado . There was great similarity between the bee guilds in EEP and FPB. The composition of species of each guild varied more among the three areas than the richness and abundance. The comparison between the bee guilds collected in EEP in 1988/89 and 2005/2006 made the changes in abundance and composition of species evident. The proportion of natural vegetation, the location and the biology of each species, such as in the case of Melipona, are factors that influenced the structure of the bee guilds. Other flower visitors of Matayba guianensis were the Coleoptera, with 35 species, the Diptera, with 37 and wasps, with 54. Some of these species, as Ornidia obesa and Palpada sp.1, may act as pollinators. Other species are probably damaging the plant, as the phytophagous Coleoptera. Matayba guianensis is a key plant in the maintenance of guilds of bees as well as of other Cerrado insects.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

The semideciduous seasonal forests (SSF) of southeastern Brazil have a high floristic diversity, accompanied by a high beta diversity, even between nearby fragments. However, nowdays these forests have been represented by a large number of small fragments, a landscape pattern typical for this region. In addition to the processes related to fragmentation, the human impact, in particular on the remaining forests, is an important force to modify plant communities, generating spatial and temporal heterogeneity and changing the composition and community structure. To determine the floristic composition and structure of forest remnants is an important way to help the maintenance and conservation of these natural relics. The objective of this study was to increase the knowledge about the flora of semideciduous seasonal forests of the Triângulo Mineiro, through a study of the composition and structure of the tree component, in ten forest fragments located in five municipalities of region. The Triângulo Mineiro is located in the far west of Minas Gerais State, defined by the geographical coordinates 18º29 19º40 S e 47º30 - 49º53 W. The site of sampling in each fragment was an hectare plot placed as central as possible in the FES. All alive individual trees with CAP (circumference at breast height, 1.30 m) ≥ 15 cm were sampled, identified and measured. A similarity analysis was done using the Jaccard's coefficient. A data ordination was carried out using the Detrended Correspondence Analysis (DCA). To complement this, we used a dichotomous hierarchical division by TWINSPAN. Stratification was realized by species and not by individuals, using a nonparametric statistical analysis by quartile and median. An analysis of variance (ANOVA) was used to test the differences between the soil and among fragments, and a post-hoc comparison of the means was done using the Tukey test at 5%. A structured matrix was created with the information (scores) obtained from the evaluation of the array, severity and duration of selected environmental impacts, besides the information about the environment array and of the edge type. A correlation analysis was done between the scores of the impact matrix and the variables of the tree community structure. Finally, the species were classified according to the sucessional groups, dispersal syndromes and deciduousness. The FES of the Triângulo Mineiro have a high species richness, consisting of 242 tree species, distributed in 163 genus and 58 families. Out of the 242 species, only Copaifera langsdorffii Desf. and Hymenaea courbaril L. occurred in all fragments. The levels of floristic similarity between the areas were low, indicating a high heterogeneity in relation to tree species. The classification by TWINSPAN separated the areas into two groups in the first division. The fragments of Uberaba, Água Fria and Ipiaçu formed a distinct group, due to lack of Siparuna guianensis, specie considered as an indicator for the others fragments. As for environmental groups, the FES of the Triângulo Mineiro showed a pattern formed by zoochoric species, early secondary and perennial, which coincides with the pattern found for the tropical season forests. The methodology applied in this study for stratification analysis was effective for the recognition of three tree layers. The variations found for the values of quartile and median represent the historical development of the succession of each fragment, allowing vertical variations in the occupation by species characteristic of certain strata. The analysis of the vertical structure of the FES of the Triângulo Mineiro allowed clearly to see the division of species and their ecological groups exercising their functions in each of the strata. The FES of the region are characterized by a variation in soil types and can be, divided into two groups: the areas of eutrophic and dystrophic soils. However, there was no relationship between these groups and the diversity in the fragments. Areas of extremely dystrophic soils showed high species richness. The species diversity of the fragments increased in areas characterized by intermediaries disturbances leves and / or when inserted in forest gradients. Species richness decreased with the severity of human impacts and edge effects and also with the conservation degree of the fragments. The mechanisms for generation and maintenance of the tree species richness and diversity of semideciduous seasonal forests of the Triângulo Mineiro respond to variation in levels of natural and anthropogenic disturbances, in other words, the historical use and occupation of the area, mainly by the availability for use by the owners, directly influences the natural dynamics of forest succession and allows the development to mature stages.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

CHAPTER I: The present study has the objective to describe the life history of Aglaotenus lagotis since the youngest birth until adulthood, analysing the number of eggs in each cocoon, the birth rate, the instar number, sexual ratio and development time until adulthood, quantifying the size cephalothoraxes during all the stages of the development. The results indicate that the species is able to produce two egg sacs during the reproductive period with twelve instars after the outbreak. The youngest, during the development had the greatest a mortality rate on the three first instars, what characterizes a type III survival curve. During the adulthood the sexual ratio was turned to the female, and there is no significant differentiation between the cephalothoraxes width between males and females in laboratory environment, what makes it possible to, be considered a monomorphic species. The sexual dimorfism was observed on the coloration. Males show a light brown coloration and the female show a dark one. This study provides an opportunity to evaluate all the phases of life cycle of Lycosidae A. lagotis, what can help on the initial construction of studies about the post-embryonic development of the species, offering comparative parameters with other species from this family. CHAPTER II: The present study shows the description of the sexual behavior and the maternal care of the spider A. lagotis (Lycosidae), testing by experiments the hypothesis that the male of A. lagotis is attracted by chemical cues in the sheet web built by the female. A maternal care behavior is described, testing the hypothesis that youngest from the studied species that had maternal care have a greater fitness than youngest without the maternal care. The study made it clear that males are able to observe, note, identify realize chemical cues in the web, telling virgin females from females that were fertilized. It was possible to quantify e categorize the sexual behavior of the males into three different categories: court, pre-mate and mate. After the mate, the females built an cocoon that was transported adhered in the spinnerets and hold by the last pair of legs. After the outbreak of the eggs, the youngest migrated to a dorsal region of the mother s body for five days. It was observed during the maternal care that the mother eliminates a yellowish drop from its cheliceraes which is collected by the youngest. During the development of the youngest until the adulthood, the youngest that have the presence of their mother in the first stages of life have a greater survival, if compared with the ones that do not have the presence of their mother. So, for the A. lagotis species, by its abundance and wide distribution represent an interesting model of study for the hypothesis test in behavioral ecology, which makes possible new comparative analyses with other species of Lycosidae. CHAPTER III: The present study shows the ecological aspects of A. lagotis from two distinct populations, in a semi-deciduous dry forest in Araguari municipality, Minas Gerais. the study was developed in four distinct periods october 2008, january, april and july 2099, in two different sites. the results show that A. lagotis is a seasonal species, with an aggregated distribution and with a strong parental similarity component between the individuals from the same region. The life history of A. lagotis seems to be characterized by seasonal aspects, seen that some components of its life cycle show a well defined period of ocorrence. As long as they grow, both the area and the height of the web get bigger with the individual size, what suggests that webs progressively bigger and taller are necessary for the capture of prey enough for the maintenance of the individual biomass. Despite of happening little variation in the number of spider tenant individuals associated to the vertical interception web between the studied areas (except for April), a positive correlation was characterized between these variables in all the samples. It means that, the greater the volume of the vertical web, the greater the number of parasite spiders. So, the variations in the densities of spiders between the study sites and through time in each site, observed in this study, can be the result of the interaction between several factors, as the availability of food, climate factors and other parameters that must be investigated in future studies.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Universidade Federal de Goiás - Goiânia

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

In the last two decades new species were discovered living in complex social organizations, besides the hymenopterans and isopterans. Examples as the naked mole-rat, coral-reef shrimps, aphids, thrips and beetles were added to the lists of eusocial species. Intermediate degrees of sociality were also described in arachnids as the spiders, amblypygids and uropygids, harvestmen, scorpions, and now pseudoscorpions. Although there is great resistance in the use of social behavior classifications, which usually privilege the eusocial species, we cannot deny that a lot of species took convergent pathways. Independently of the degree of social complexity, each species has unique perspectives in understanding the evolution of cooperative behaviors, especially the intermediate species. In this manuscript I present the natural history of a small social-permanent arachnid, capable to live in large colonies maintained by collective work and complex cooperative behaviors. Although it is not a new species for the science, we know very little about it social behavior. Now, we know that only two among the more than three thousand known pseudoscorpion species live in complex obligate societies. In this study we will present the natural history of Paratemnoides nidificator (Balzan, 1888) (Atemnidae) and their differences in relation to solitary pseudoscorpions; cooperative forage and dispersion and it implications for the maintenance of sociality in this group. We will discuss the existence and the evolution of division of labor; and also the existence that a second way of social life based on parasitism; and finally, a revision about the social behavior in the Pseudoscorpiones order and an evaluation of the main factors in the selection this way of life. These small and discreet animals can tell us a surprising history and help us to better understand the evolution of the social behavior in arthropods.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Communication is a very important factor for the maintenance of several vital ecological processes among animals. Among birds, the acoustic communication has primordial role and it is indispensable for reproduction, to repel predators and in social dynamics. Body size imposes physiological constraints to the vocal apparattus, and consequently, limits the components of vocalizations. The environment also inflicts certain physical restrictions to the acoustic signs and limits the transmissibility of information. The Acoustic Adaptation Hypothesis (HAA) predicts a different selection for vocalization characters in forest habitats. Specifically, frequencies in forest habitats tend to be affected by attenuation, absorption and reverberation, effects imposed by physical barriers in this environment. The present work tested the HAA using 142 bird species and five major clades widely distributed in Brazil, considering body size and two phylogenetic comparative methods: pairwise comparisons and phylogenetic independent contrasts. None of the Suboscine vocal characters were correlated to morphology. Most of the predictions of AAH were not corroborated and varied between clades.

The agriculture expansion over native vegetation has provocaded habitat fragmentation in main Brazilian biomes. It was described the vegetation and the entomofauna of four semi deciduous forest fragments, which represent remnants of the Atlantic Rainforest, inserted in the Cerrado domain, as well as the abundance and the body size and symmetry of the ant Pachycondyla cf. crassinoda (Ponerinae) in these fragments. The study area is located at the Itumbiara, state of Goias, Brazil, situated in the Paranaíba river valley. This area has intensive agricultural activity that has been accelerating the deforestation of natural process. The following hypotheses were tested: 1) the remnants that are geographically closer tend to be floristically more similar and the fragment size is directly related to its biological diversity, 2) fragment size and floristic composition influence the entomofauna community structure in terms of richness and abundance, 3) the fragment size affects the abundance and the fluctuating asymmetry (FA) population levels of a formicinae population and the size of their individuals. It was also investigated in this ant population whether there are correlations between body s size and symmetry with the individual s abundance and the climatic conditions. The floristic composition, the body s size and FA of Pachycondyla cf. crassinoda were influenced by the fragment size. Smaller fragments were floristically more similar to each other, despite not being geographically close and the entomofauna similarity between fragments was independent of the fragment size. The vegetation diversity did not linearly interfered with the insects abundance, but the rainfall significantly affected the density, the size and the FA of P. cf. crassinoda. All studied forest remnants are important for conservation of the local biological diversity, regardless of their size. The evaluation of forest fragmentation impact should considered a combination of several factors such as the size of the area, the surrounding matrix, the degree of isolation and the local biotic and abiotic factors.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais