Population structure and breeding period of Pachycheles monilifer (Dana) (Anomura, Porcellanidae) inhabiting sabellariid sand reefs from the littoral coast of São Paulo State, Brazil

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

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)

Shell utilization pattern of the hermit crab Clibanarius vittatus (Crustacea, Anomura) in an estuary at São Vicente, State of São Paulo, Brazil

O objetivo do presente estudo foi avaliar a utilização de conchas de gastrópodes por Clibanarius vittatus (Bosc, 1802), na Praia dos Pescadores, em São Vicente (SP), Brasil. Foram realizadas amostras mensais no período de maio de 2001 a abril de 2003, na região intertidal durante a maré baixa. Todos os animais foram pesados e tiveram o comprimento de seu escudo cefalotorácico mensurados, suas conchas identificadas e medidas quanto ao comprimento (mm), abertura (mm) e peso (g). Capturamos 2.344 ermitões (644 machos, 1.594 fêmeas não-ovígeras, 45 fêmeas ovígeras e 61 em intersexo), utilizando 13 espécies de conchas de gastrópodes, das quais Stramonita haemastoma (Linnaeus, 1767), Cymatium parthenopeum (Von Salis, 1793) e Achatina fulica (Bowdich, 1822) representaram mais de 98% das conchas utilizadas. Obteve-se significativa diferença de tamanho entre os sexos, com machos e indivíduos em intersexo atingindo maior porte físico do que fêmeas. Este padrão influenciou fortemente na ocupação e utilização de conchas, principalmente em A. fulica, que foi a maior concha obtida por C. vittatus, utilizada somente por machos e indivíduos em intersexo. Cymatium parthenopeum foi a única espécie de concha em que se obtiveram elevados coeficientes de determinação para todas os parâmetros analisados. Stramonita haemastoma apresentou elevados e significativos coeficientes de determinação, indicando que esta espécie é o principal recurso de concha ocupada na Praia dos Pescadores.

Desenvolvimento pós-embrionário de Pagurus brevidactylus (Stimpson, 1858) (Decapoda, Paguridae), em laboratório

All the larval stages of the hermit crab Pagurus brevidactylus were studied in the laboratory, with special emphasis on external morphology and on the duration of each stage. The larvae were kept in individual containers, with water of 35 salinity and fed on nauplii of Artemia salina; room temperature was maintained at 24±1ºC. The post-embryonic development includes four stages of zoea and one of megalopa. All the larval stages are drawn and described in detail.

On a record of Dardanus venosus (H. Milne Edwards) (Crustacea, Anomura) from the São Paulo State, Brazil

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

Selection and shell relationship in Isocheles-sawayai forest and Saint-laurent, 1967 (crustacea, anomura, diogenidae)

A populational sample of Isocheles sawayai Forest & Saint Laurent, 1967 was analysed in order to detect the validity of the shell aperture size as a parameter in the gastropod shell selection. The gastropods genus occupied by this hermit crab were: Thais, Buccinanops, Olivancillaria, Polinices and Cymatium. The power function (y = a.x(b)) was the best equation to represent biologically the regression analyses carried out among the measured parameters.

Population dynamics of Petrochirus diogenes (Crustacea, Anomura, Diogenidae) in the Ubatuba region, São Paulo, Brazil

This work examines the population dynamics of Petrochirus diogenes in the Ubatuba region (São Paulo, Brazil), focusing on size frequency distribution, sex ratio, and reproductive and recruitment period. Collections were made with two double-rig nets in the years 1993-1996. The 799 individuals obtained were separated into 14 size classes based on the length of the cephalothoracic shield. The shield size varied from 5.4 to 40.0 mm in males and from 5.7 to 32.1 mm in females. The size frequency distribution was unimodal for both sexes. Only small oscillations occurred in the sex ratio until the seventh size class, followed by preponderance of males. This suggests a standard pattern for the sex ratio in P. diogenes. As males were found in the largest size classes, they present a clear sexual dimorphism. This characteristic can be considered as a selective advantage, mainly during the mating processes and in the agonistic behavior. Ovigerous females were recorded in the spring and summer, indicating seasonal reproduction.

Feeding preference of the South American endemic anomuran Aegla platensis (Decapoda, Anomura, Aeglidae)

In order to determine the feeding preference of Aegla platensis in streams and the importance of microorganisms in its detritivore diet, we carried out two experiments designed to evaluate the food preferences of A. platensis (1) among leaves with different levels of microbial colonization and (2) among insect larvae (Chironomidae, Simuliidae, Hydropsychidae) and microbially conditioned leaves. A. platensis preferred animal over plant food items; when only leaves were offered, this aeglid preferred the leaves with higher levels of microorganism conditioning.

Population biology and reproduction of the hermit crab Clibanarius vittatus (Decapoda: Anomura) in an estuarine region of southern Brazil

The population dynamics and reproduction of the hermit crab Clibanarius vittatus were evaluated on Pescadores Beach, located on the estuarine channel of Sao Vicente (São Paulo), Brazil. The hermit crabs were captured by hand during low tide,from May 2001 to April 2003. A total of 2554 hermit crabs were captured, of which 701 were males, 1741 non-ovigerous females, 48 ovigerous females and 64 intersex individuals. The size-frequency distribution of the males was represented by a platykurtic bell-shaped curve, which differed from the leptokurtic bell-shaped curve of the females. The smaller and intermediate classes were composed mainly of females (modal size 6.5-7.5 mm carapace shield length (CSL)), and the larger classes only by males (modal size 9.5-10.5 mm CSL). The overall sex-ratio was skewed toward females (0.39:1/M:F), differing significantly from the expected 1:1. A seasonal reproductive pattern was recorded for C. vittatus in this location, with more intensive reproductive activity in the warmer months. The absence of juveniles suggests that their recruitment area is different than the area inhabited by adults, possibly another area with more protection and specialized or different resources for young.

Morphometry and sexual maturity of the tropical hermit crab Calcinus tibicen (Crustacea, Anomura) from Brazil

Ontogenetic changes in relative growth were studied in the hermit crab Calcinus tibicen in order to determine its growth phases with sexual maturity. Specimens were collected at 2-month intervals for two consecutive years. A total of 570 individuals was collected and analysed. Total mean animal size in terms of shield length was 5.14±1.23mm for males, 4.23±0.79mm for females and 4.53±0.60mm for ovigerous females. Sexual dimorphism in chela dimensions was stronger in males than in females. Differences between males and females were found in left propodus length (LPL) and height (LPH) versus shield length (SL) and wet weight (WW) versus SL relationships. Males showed a high positive allometry, while juveniles and adult females were isometric for the LPL/SL relationship. Negative allometry was observed in adult females in the LPL/SL relationship. The size at which a differentiation occurred in the growth of the chelipeds and in the weight gain of males and females was between 3.0 and 3.2mm SL, suggesting that sexual maturity occurs in small-sized individuals in the life cycle of C. tibicen.

Utilization of shells of the snail Achatina fúlica Bowdich, 1822 (Mollusca, Gastropoda) by the hermit crab Clibanarius vittatus (Bosc, 1802) (Decapoda, Anomura) in the São Vicente Estuary, São Paulo, Brazil

Hermit crabs depend on mollusc shells for housing. In this study, an unusual resource is reported for a hermit crab that usually inhabits marine gastropod shells. During a field study conducted from May 2001 to April 2003 in an estuarine area in São Vicente, state of São Paulo, Brazil, 21 individuals of Clibanarius vittatus (Bosc, 1802) were found inhabiting the shells of the terrestrial gastropod Achatina fullea Bowdich, 1822. A. fúlica occurs in nearshore grass patches, where occasional contact with sea water kills them, and their shells then become available to the hermit crabs.

Dinâmica da comunidade de Anomura (Crustacea, Decapoda) no litoral paulista: uma análise análise comparativa em dois períodos distintos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Morfologia e distribuição dos estágios larvais de representantes das famílias Diogenidae e Paguridae (Crustacea: Decapoda: Anomura) obtidas no nêuston da região de Ubatuba, SP

Pós-graduação em Ciências Biológicas (Zoologia) - IBB

Taxonomia e distribuição da família Porcellanidae Haworth (Crustacea: Decapoda: Anomura) no litoral brasileiro

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Variação mensal da densidade das larvas de Anomura macleay, 1838, Axiidea saint laurent, 1979 e Gebiidae saint laurent, 1979 (Crustacea, Decapoda) em um estuário amazônico (Pará, Brasil), com descrição dos primeiros estágios larvais de Upogebia vasquezi ngoc-ho, 1989 obtidos em laboratório

A dissertação foi elaborada no formato de artigos, separados em capítulos, conforme formatação do Programa de Pós-Graduação em Ecologia Aquática e Pesca da Universidade Federal do Pará. O capítulo geral contém uma breve introdução sobre a biologia geral de anomuros (Infraordem Anomura) e talassinóideos (Infraordens Axiidea e Gebiidea), seguido pelos objetivos e metodologia geral utilizada para a obtenção dos resultados que culminaram com a elaboração dos três capítulos restantes da dissertação, que serão submetidos à publicação. O capítulo 1 foi específico para a investigação da variação espaço-temporal das espécies de anomuros que utilizam o estuário de Marapanim (PA) durante a fase larval, e sua relação com os fatores abióticos (temperatura, salinidade e pH). O capítulo 2 contém os resultados obtidos quanto à ocupação do estuário pelas larvas e adultos das espécies de talassinóideos obtidas ao longo dos meses do ano. Este foi o único grupo em que houve a possibilidade de analisar, de forma integrada, as amostras de larvas, juvenis e adultos presentes no estuário. Em razão da dificuldade encontrada na identificação das amostras de larvas de Decapoda (Anomura, Axiidea e Gebiidea) coletadas no estuário de Marapanim (PA) ao longo do ano, optou-se por efetuar o desenvolvimento larval de Upogebia vasquezi, obtido em laboratório, culminando com a inclusão do capítulo 3, que contém a descrição dos dois primeiros estágios larvais desta espécie. Por fim foram apresentadas as conclusões gerais e as perspectivas de continuidade nos estudos com estes táxons nos estuários paraenses.