Nest site selection by sea turtles

The distribution of 38 nests of loggerhead turtles (Caretta caretta) on beaches on Sanibel and Captiva islands, south-western Florida (26°26'N 82°16'W), and of 70 first digging attempts by green turtles (Chelonia mydas) on Ascension Island (7°57'S 14°22'W), was quantified. For loggerhead turtles on Sanibel and Captiva, nests were clumped close to the border between the open sand and the supra-littoral vegetation that backed the beaches. This spatial pattern of nests was closely reproduced by assuming simply that turtles crawled a random distance above the most recent high water line prior to digging. In contrast, green turtles on Ascension Island clumped their first digging attempts on the uneven beach above the springs high water line, crawling up to 80 m to reach this beach zone.

Habitat selection and energetics of the fiddler crab (Uca tangeri)

We tried to unravel the possible links between the skewed predation risk in Uca tangeri (where large individuals are more at risk from avian predators) and size-dependent changes in the physiology and habitat choice of this fiddler crab species. Over a transect running from low to high in the tidal zone of a beach in Mauritania, the temperature profile at various depths in the substrate, the water-table level of seep water, salt concentration of seep water, depth of the aerobic level, operative temperatures on the surface, and size distribution of crabs were assessed. In addition, resting metabolic rates, Q10 and thermal and starvation tolerances were estimated. Going from low to high in the tidal zone, crab size and burrow depth increased. At the preferred burrowing depth, microclimatological conditions appeared to be equally favourable at all sites. At the surface, conditions were more favourable low in the tidal zone, where also food availability is sufficient to enable small crabs to forage in the vicinity of their burrows. Large crabs have higher energy requirements and are thereby forced to forage in flocks low in the tidal zone where food is probably more abundant. Low in the tidal zone, digging deeply is impossible as the aerobic layer is rather thin. Large crabs prefer living high in the tidal zone as (1) deep burrows ensure better protection against predators, (2) more time is available for digging holes and (3) the substrate is better suited for reproduction. Energy reserves in late summer ensured an average of 34 days of survival. It is argued that the allotment of energy to growth must be considerable even in reproducing animals; the rewards of growth being the disproportional increase in reproductive output with size.

Relationship Between Population Size and Symbiont Fungus Culture Volume in Colonies of Acromyrmex balzani (Hymenoptera: Formicidae)

In order to quantify the population of Acromyrmex balzani Emery, 1890 nests and to verify whether the population dynamic of the colony is correlated with the symbiont fungus volume, the principal energy source of the colony, five nests located in grassland areas were evaluated. The nests were sprayed with neutral talcum powder to improve visualization and digging. The symbiont fungus and the entire population existent in the chambers were collected. The mean fungus volume and total nest population in excavated nests were, respectively, 74.76 ml and 1,095 individuals. Simple linear correlation analysis verified that the fungus volume grew proportionally to the number of individuals. Despite the correlation between fungus volume and population dynamic of colonies, the factors that determine this relationship are little known since other microorganisms live in association with the colony.

Lipid and energy contents in the bodies of queens of Atta sexdens rubropilosa Forel (Hymenoptera, Formicidae): pre-and post-nuptial flight

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Comportamento alimentar do camarão marinho farfantenaeus subtilis em condições laboratoriais

Shrimp culture represents an important activity to brazilian economy. The northeastern region has presented high levels of production because of its climatic conditions. An important factor for the activity´s major development is related to the introduction of the species Litopenaeus vannamei. The use of an exotic species can disturb the ecosystem. In the last decades, L. vannamei has been the only species cultivated in Brazilian farms, there not being an alternative species for shrimp culture. So, there is an urgent need to developing new studies with the native species, which might represent an alternative concerning shrimp production, with emphasis on Farfantepenaeus subtilis. Another important aspect related to the activity is feeding management, once it is quite usual that feed offer on the pond does not take into account either the species´ physiology and behavior or the influence of environmental variables, such as light cycle and substrate. That knowledge may optimize management and so reduce the impact of effluents in the environment. This study´s objective was characterizing feeding behavior of F. subtilis in laboratory. For that, an ethogram was developed, using 20 wild animals which were observed through ad libitum and all occurrences methods. Two experiments were developed in order to register feeding behavior on different substrates, along 15 days, each. In the first experiment, 40 animals were distributed in eight aquaria, half being observed during the light phase of the 24 hour cycle and the other half in the dark phase, both in halimeda substrate. In the second experiment, 20 animals were distributed in four aquaria, under similar conditions as the previous ones, but in sand substrate. In both experiments, animals were observed respectively one, four, seven and ten hours after the beginning of the phase, for light phase, for the dark phase, in ten minute observation windows, before and immediately after feed offer. The following behaviors were registered: feed ingestion, ingestion of other items, inactivity, exploration, vertical exploration, swimming, crawling, digging, burrowing, and moving by the animals. Observation windows after feed offer also included latency to reach the tray and to ingest feed. Nineteen behaviors were described for the species. F. subtilis presented more behavioral activities in halimeda substrate even in the light phase, while burrowing was predominant in sand substrate. In both substrates, moving, crawling and exploration were more frequent after feed offer, but inactivity and burrowing were more frequent before that. Feed ingestion was more frequent in halimeda, both in light and dark phases. Weight gain was also more prominent in that substrate. In sand substrtate, ingestion was more frequent in the dark phase, which suggests that higher granulometry facilitates feed ingestion in F. subtilis juveniles. Our results demonstrate the importance of studies for the better knowledge of the species, specially its response to environmental stimuli, in order to improve animal management

Influência da densidade de estocagem sobre o crescimento, ciclo de muda e o comportamento em juvenis do camarão marinho Litopenaeus vannamei

One of the factors that may interfere with the cultivation of Litopenaeus vannamei is the population density. This study aimed to assess the effect of density on growth, mortality, physical integrity and behavior of shrimp. The study was divided into two stages. At first, the shrimp were placed in tanks at densities of 50, 75 and 100 shrimp m-2. The animals were monitored in relation to the degree of proventricular filling, the stage of the molt cycle and physical integrity three times a week and in relation to the weight and length once a week. Mortality, growth and proventricular filling were not influenced by the density; frequency of records in specific stages of the molt cycle varied according to the density. The lower proportion of broken appendages and higher frequency of necrotic lesions occurred in lower density. The second stage of the research, conducted in aquaria, was divided into two parts. The first described social or feeding behavioral categories: slow displacement by contact, slow displacement by approximation, abrupt displacement by contact, abrupt displacement by approximation, reactivity, cannibalism, occupying the tray, get feed in the tray and get feed outside the tray. In the second part, these and other behavioral categories, described in the literature, were recorded in densities of 50, 75 and 100 shrimp m-2. Mortality was more frequent in higher density. The frequency of most behaviors mentioned above was very low, not differing between densities or being too low to determine differences between them. The behavioral profile of animals in different densities was, in general, very similar, with no difference in exploration, digging and cleaning between the densities. Even so, inactivity, feeding, crawling, burrowing, swimming, and proximity between animals were influenced by the density. These results suggest that some behaviors suffer greater interference from population density. However, the density may not have a broader influence on the animals when other factors, such as physico-chemical parameters of water and feed offering, are adequate

Dois testes de imageamento com GPR em problemas de controle ambiental em regiões tropicais: migração de dunas e localização de dutos de óleo enterrados

Because the penetration depth of Ground Penetrating Radar (GPR) signals is very limited in high conductive soils, the usefullness of this method in tropical regions is not yet completly known. The main objective of this researh is to test the usefullness of the method in Brazil. Two typical problems where GPR has been used in Europe and North American were choosed for this test: the first one is to characterize the internal structures of a sand body and the second problem is the localization of old buried pipes lines. The first test was done near the city of São Bento do Norte, in the northern coast of Rio Grande do Norte state, NE Brazil. In this region, there is a sand dune that is migrating very fast in the direction of adjacent settling areas. To characterize the internal structure of the dune and its relationship to the prevailing wind direction, as a preliminary step to understand the dune migration, GPR profiles using the 400 MHz frequency were performed in E-W, N-S, NE-SW, and SE-NW directions over the sand dune intersecting at the top of the dune. The practical resolution of the GPR data is around 30 cm; this was sufficient to distinguish individual foresets inside the dune. After applying the elevation correction to the data, we identified that dips of bedding structures are smallest for the N-S profile, which is perpendicular to the dominant wind direction, largest for the E-W profile, and intermediate for the SW-NE and SE-NW profiles. Foresets in the E-W profile dip with angles varying from 2 to 6 degrees. In the E-W profile, the water table and a horizontal truncation interface separating two generations of dunes were identified, as well as an abrupt directional change in the foreset patterns associated to a lateral contact between two dune generations, the older one extending to the west. The used high frequency of 400 Mhz does not allow a penetration deep enough to map completely these internal contacts. The second test was done near Estreito, a small town near Carnaúbais city, also in Rio Grande do Norte state. In this locality, there are several old pipe lines buried in area covered by plantations where digging should be minimized. Several GPR profiles using the 400 and 200 MHz frequency were performed trying to intercept perpendicularly the possible pipe lines. Because of the high conductivity of the soil, the raw original data can hardly be use to identify the pipe lines. However, after an adequate processing over the 200 MHz profiles, six pipe lines were identified. As a global result of the tests, GPR can be very usefull if the conductivity of the ground is low or, in the case of medium conductivities of the soils, if adequate processing is performed

Population and reproductive biology of the crab Uca burgersi (Crustacea : Ocypodidae) in three subtropical mangrove forests

Population and reproductive biology were studied in three populations of the crab Uca burgersi Holthuis, 1967, in the Indaia, Cavalo and Ubatumirim mangrove forests (Ubatuba, São Paulo State, Brazil). Crabs were collected during low tide (August 2001 through July 2002), by digging the sediment, with a standard capture effort (two persons for 30 min.). Carapace width was measured, and gonad developmental stage was recorded from all specimens. U. burgersi was most abundant in the Cavalo mangrove, where the largest mate was found. Juvenile crabs were found year-round at all three sites. However, the ratio of ovigerous females was very low, even null in the Cavalo mangrove. The gonad development rate indicated that U. burgersi was reproducing continuously, but more intensively during spring and summer, with recruitment occurring in winter. The synchrony between the populational and reproductive biology in the three areas showed that local features were not the limiting factors. It is suggested that this species is a habitat generalist.

The size of excavators within a polymorphic termite species governs tunnel topology

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

A comparative tunnelling network approach to assess interspecific competition effects in termites

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Functional and historical determinants of shape in the scapula of Xenarthran mammals: Evolution of a complex morphological structure

The mammalian scapula is a complex morphological structure, composed of two ossification plates that fuse into a single structure. Most studies on morphological differentiation in the scapula have considered it to be a simple, spatially integrated structure, primarily influenced by the important locomotor function presented by this element. We used recently developed geometric morphometric techniques to test and quantify functional and phylogenetic influences on scapular shape variation in fossil and extant xenarthran mammals. The order Xenarthra is well represented in the fossil record and presents a stable phylogenetic hypothesis for its genealogical history. In addition, its species present a large variety of locomotor habits. Our results show that approximately half of the shape variation in the scapula is due to phylogenetic heritage. This is contrary to the view that the scapula is influenced only by functional demands. There are large-scale shape transformations that provide biomechanical adaptation for the several habits (arboreality, terrestriality, and digging), and small scale-shape transformations (mostly related to the coracoid process) that are not influenced by function. A nonlinear relationship between morphometric and phylogenetic distances indicates the presence of a complex mixture of evolutionary processes acting on shape differentiation of the scapula. J. Morphol. 241,251-263, 1999. (C) 1999 Wiley-Liss, Inc.

Osteology and Intraspecific Variation of Leptodactylus podicipinus (Anura: Leptodactylidae), with Comments on the Relationship between Osteology and Reproductive Modes

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

O jardim de fungo atua como um molde para a construção das câmaras em formigas cortadeiras?

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

DISTRIBUIÇÃO DE SUBSTRATOS NAS COLÔNIAS DE Atta laevigata (F. Smith, 1858) (HYMENOPTERA: FORMICIDAE)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Description and interpretation of Cenozoic vertebrate ichnofossils in Rio Grande do Sul State, Brazil

In the neighborhood of the city of Boqueirão do Leão (State of Rio Grande do Sul, Brazil) a set of three big-sized tunnels has been found. One of the tunnels is only partially filled with sand and accessible along its entire length. It is horizontal, slightly sinuous, 36 m long, up to 4.2 m wide and up to 2.0 m high. The surface morphology of the walls is composed of anthropogenic marks, speleothems, black incrustations and traces like digging scratches and smoothed surfaces. The 2nd tunnel has its entrance blocked by sand and sandstone cobbles, but the end of the tunnel is only partially clogged and therefore accessible. This accessible portion is 12 m long, 3 m wide and 1.5 m high. The 3rd tunnel is completely filled and collapsed and is nowadays only indicated by concave roof features at its end. The general features of the tunnel system and the analysis of the surface morphology of the walls of the accessible portions permit to conclude that the tunnels were produced by ground sloths of the Cenozoic South American megafauna. The size of the tunnels suggests that its excavation was gradually carried out by successive generations of sloth herds, and not by a single individual animal. The primary function of the tunnels probably was not protection from predators, which had easy access to structures of this size, but to shelter during a drier climate. However, it is not yet possible to relate the tunnels to a specific ground sloth genus, a task that depends on the discovery of better-preserved tunnel systems. © 2013 by the Sociedade Brasileira de Paleontologia.