Relative growth and sexual maturity of the stone crab Menippe nodifrons Stimpson, 1859 (Brachyura, Xanthoidea) in southeastern Brazil

O objetivo do presente estudo foi determinar o crescimento relativo e a maturidade sexual morfológica de Menippe nodifrons. As coletas foram realizadas na Praia Grande e Tenório, Ubatuba, São Paulo. Os caranguejos foram separados quanto ao sexo e mensurados na região da largura (LC) e comprimento da carapaça, comprimento e altura dos própodos quelares direito e esquerdo, largura do abdome (LA) nas fêmeas e comprimento do gonopódio (CG) nos machos. Obteve-se 399 indivíduos, sendo 195 machos e 204 fêmeas. Os machos atingiram a maturidade sexual com 29,7mm LC e as fêmeas com 31,6mm LC. Para as fêmeas a melhor relação que indicou a muda da puberdade foi LA vs. LC, sendo que o crescimento foi alométrico negativo na fase jovem e alométrico positivo após a muda da puberdade. Para os machos foi CG vs. LC evidenciando crescimento alométrico positivo na fase jovem e isométrico na fase adulta.

Relative growth of Petrochirus diogenes (Linnaeus, 1758) (Crustacea, Anomura, Diogenidae) in the Ubatuba region, São Paulo, Brazil

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

Relative growth of Uca burgersi (Crustacea, Ocypodidae) from two mangroves in the southeastern Brazilian coast

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

Composition of the aquatic invertebrate fauna associated to the mangrove vegetation of a coastal river, analyzed through a manipulative experiment.

The present study analyzed the composition of the aquatic fauna associated to the mangrove forest in a southeastern Brazilian river. The composition of the macrofauna in the roots of the marginal vegetation located at three different salinity stretches was analyzed by sampling pieces of the submerged branches of the vegetation (natural substrate) and pieces of sisal rope (artificial substrate), installed close to the natural vegetation and sampled after a period of 14 colonization days. In both types of substrate, twelve taxonomic groups were sampled, representing three phyla (Cnidaria, Annelida and Arthropoda). The crustaceans, corresponding to the most diversified group, were represented by Copepoda, Tanaidacea, Isopoda, Amphipoda and Decapoda. The highest salinity stretch showed the highest abundance, with a progressive decrease from high to low salinity for both substrates. Copepoda and Tanaidacea predominated on both substrates, although the artificial substrate exhibited the highest total abundance and species richness. Considering the relative abundance of the taxonomic groups on both substrates, the majority of groups predominated in the highest salinity range. Significant differences on the longitudinal distribution of abundance were associated to the variation on salinity and with the complexity of the substrate.

Relative growth and morphological sexual maturity of Uca Cumulanta (Crustacea : Decapoda : Ocypodidae) from a tropical Brazilian mangrove population

The relative growth of the fiddler crab Uca cumulanta was studied, primarily to determine the size at the onset of sexual maturity for a mangrove population in the estuary of the Patitiba River, Paraty, Rio de Janeiro state, Brazil. The evaluation of the morphological sexual maturity of U. cumulanta was performed using the allometric technique. The relationships that most precisely indicated the size at onset of sexual maturity were carapace length (CL) vs propodus length for males and CL vs abdomen width for females. Males and females are mature at 5.25 and 4.75 mm CL, respectively. The remarkable ontogenetic changes observed in the allometric growth of the male major cheliped and the female abdomen, indicate that growth of these structures is closely connected to the timing of sexual maturity. The relative size at onset maturity obtained for this species was 0.68 and this index was compared to that seen in other species in the genus.

Mesabolivar brasiliensis (Moenkhaus 1898) and Mesabolivar cyaneotaeniatus (Keyserling 1891) (Araneomorphae, Pholcidae): close relationship reinforced by cytogenetic analyses

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

The movement of involucral bracts of Syngonanthus elegans (Eriocaulaceae-Poales): Anatomical and ecological aspects

Syngonanthus elegans flowers are distributed in capitula whose involucral bracts open and close in a diurnal rhythm. The anatomy of these bracts was studied to understand how such movements occur and how it influences reproductive ecology of the species. The involucral bracts have a single layered epidermis composed of thick-walled cells on the abaxial surface, which are responsible for the movement. Since they are hygroscopic, these cells swell when they absorb water from the surrounding environment, causing the bracts to bend and the capitula to close. In natural conditions, the capitula open by day, when temperature increases and the relative air humidity decreases, and close at night, when temperature decreases and the relative air humidity increases. The involucral bracts may thus protect the flowers from abiotic factors, exposing them only at the time of the day when temperature is higher and insects are more active, favoring pollination by small insects. The closed capitula do not only protect the flowers, but they also function as a shelter for floral visitors as Brachiacantha australe (Coccinellidae) and Eumolpini sp. (Chrysomelidae). These small Coleoptera pollinate the flowers of S. elegans during the day and remain within the closed capitula during the night, in a possible mutualistic relationship. (C) 2008 Elsevier GmbH. All rights reserved.

Microsporogenesis is simultaneous in the early-divergent grass Streptochaeta, but successive in the closest grass relative, Ecdeiocolea

Simultaneous microsporogenesis is described for the first time in a grass, Streptochaeta spicata Schrad., a tropical Brazilian species that belongs in the early-divergent subfamily Anomochlooideae. Microsporogenesis is successive in all other Poaceae examined so far, and most other members of the order Poales, to which grasses belong. The only other reports of simultaneous microsporogenesis in Poales are in Rapateaceae and some members of the cyperid clade (Juncaceae, Cyperaceae, Prionium and Thurnia). Among the graminids, Ecdeiocolea (the putative closest relative to Poaceae) is successive, as are Joinvillea, Flagellaria and all other Poaceae, indicating that the simultaneous condition is autapomorphic in Streptochaeta, though Anomochloa has yet to be examined. Anther wall development in Streptochaeta is of the reduced type, as also in another early-divergent grass Pharus, though most other Poales, including most grasses, have the monocot type. In Streptochaeta, as in Pharus, the endothecium lacks thickenings, unlike other grasses that have a persistent endothecium with thickenings. The centrifixed anthers and nonplumose stigmas of Streptochaeta suggest entomophily.

Genetic structure in a tropical lek-breeding bird, the blue manakin (Chiroxiphia caudata) in the Brazilian Atlantic Forest

Determining the genetic structure of tropical bird populations is important for assessing potential genetic effects of future habitat fragmentation and for testing hypotheses about evolutionary mechanisms promoting diversification. Here we used 10 microsatellite DNA loci to describe levels of genetic differentiation for five populations of the lek-mating blue manakin (Chiroxiphia caudata), sampled along a 414-km transect within the largest remaining continuous tract of the highly endangered Atlantic Forest habitat in southeast Brazil. We found small but significant levels of differentiation between most populations. F-ST values varied from 0.0 to 0.023 (overall F-ST = 0.012) that conformed to a strong isolation by distance relationship, suggesting that observed levels of differentiation are a result of migration-drift equilibrium. N(e)m values estimated using a coalescent-based method were small (<= 2 migrants per generation) and close to the minimum level required to maintain genetic similarity between populations. An implication of these results is that if future habitat fragmentation reduces dispersal between populations to even a small extent, then individual populations may undergo a loss of genetic diversity due to an increase in the relative importance of drift, since inbreeding effective population sizes are relatively small (N-e similar to 1000). Our findings also demonstrate that population structuring can occur in a tropical bird in continuous habitat in the absence of geographical barriers possibly due to behavioural features of the species.

Partitioning the relative fitness effects of diet and trophic morphology in the threespine stickleback

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Comparison between univariate and bivariate geostatistical models for estimating catch per unit of effort (cpue): A simulation study

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Why are fruits colorful? The relative importance of achromatic and chromatic contrasts for detection by birds

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

Niche occupancy and the relative role of micro-habitat and diet in resource partitioning among pond dwelling tadpoles.

We determined microhabitat and diet niche for tadpoles from two ponds in an agricultural landscape. Additionally, we verified the intraspecific variation in resource use, and if diet and microhabitat use were correlated. Tadpoles found in the two ponds differed in microhabitat use, because in the larger pond they explored deeper places far from the margin. There were three groups with high microhabitat niche overlap. In both ponds, plant cover was the best descriptor to explain interspecific variation in microhabitat use. Tadpoles of all species ingested mainly Bacillariophyceae and Trachellomonas however the diet differed intraspecifically in the species from the two ponds. Ten items in the temporary pond and 15 items in the permanent one were ingested by all species; however, the relative abundance of each item differed. Diet similarity was not correlated to similarity in microhabitat use. In this study, diet was as important as microhabitat use to explain resource partitioning.

Low-energy direct muon transfer from H to Ne10+, S16+ and Ar18+ using the two-state close-coupling approximation to the Faddeev-Hahn-type equation

We perform a three-body calculation of direct muon-transfer rates from thermalized muonic hydrogen isotopes to bare nuclei Ne10+, S16+ and Ar18+ employing integro-differential Faddeev-Hahn-type equations in configuration space with a two-state close-coupling approximation scheme. All Coulomb potentials including the strong final-state Coulomb repulsion are treated exactly. A long-range polarization potential is included in the elastic channel to take into account the high polarizability of the muonic hydrogen. The transfer rates so-calculated are in good agreement with recent experiments. We find that the muon is captured predominantly in the n = 6, 9 and 10 states of muonic Ne10+, S16+ and Ar18+, respectively.

Prediction of R plus R-2 gravity for the deflection of a photon passing close to the Sun

The cross-section for the scattering of a photon by the Sun's gravitational field, treated as an external field, is computed in the framework of R + R-2 gravity. Using this result, we found that for a photon just grazing the Sun's surface the deflection is 1.75 which is exactly the same as that given by Einstein's theory. An explanation for this pseudo-paradox is provided.