Interference And Exploitation Components In Interespecific Competition Between Sympatric Intertidal Hermit Crabs

This study was designed to evaluate the effect of interference and exploitation competition in shell partitioning between two hermit crab species (Pagurus criniticornis and Clibanarius antillensis). Field samples revealed that shells of the gastropod Cerithium atratum were the main resource used by both hermit crab species and that Pagurus used eroded or damaged shells in higher frequency than Clibanarius. The exploitative ability of each species was compared between species in the laboratory using dead gastropod (Cerithium) baits to simulate predation events and signalize newly available shells to hermit crabs. Pagurus reached the baits more rapidly than Clibanarius, but this higher exploitative ability did not explain shell utilization patterns in nature. Another experiment evaluated the dominance hierarchy between these two hermit crab species and revealed that Clibanarius was able to outcompete Pagurus for higher quality shells in agonistic encounters. This higher interference competitive ability of Clibanarius in relation to Pagurus may explain field observations. Nevertheless, Pagurus may be responsible to enhance shell availability to other hermit crab species that have lower ability to find and use newly available shells. Differently, the poorer condition of shells used by Pagurus, the higher ability of this species to attend gastropod predation events and its higher consumption rate by shell-breaking crabs (Menippe nodifrons) may increase its predation risks, thus revealing the disadvantages of such an exploitative competitive strategy for hermit crabs. © 2004 Elsevier B.V. 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Substrate Use And Selection In Sympatric Intertidal Hermit Crab Species

Coexisting hermit crabs may competitively interact for shells and microhabitats, mainly when shell availability is habitat-related. Three species of Clibanarius (C. antillensis, C. sclopetarius, and C. vittatus) coexist in the intertidal region of Pernambuco Islet, Araca Region, São Sebastiao Channel, southeastern Brazil. This study evaluated crab preferences for four substrate types used by these species in nature (rocky shore, pebbles, sand, and mud) in allopatric (single species) and sympatric (three species) treatments in simulations of high tide and low tide. The substrate preference of the three hermit crabs did not vary between low and high tide situations. At low tide the crabs either moved into holes in the highly complex rocky substrate or buried themselves in mud. Substrate selection may explain the patterns of substrate use in nature only for C. vittatus. Clibanarius antillensis and C. sclopetarius showed closer similarities in the pattern of substrate selection in the sympatric treatment with the substrate use in nature than in allopatric treatment, indicating a positive influence (dependence) of the presence of one species on the presence of another. Use of sub-optimal substrates, mainly by C. antillensis, may be caused by other factors such as its low desiccation tolerances. If competition for space takes place among these species, it would be more intense between C. sclopetarius and C. vittatus given their higher overlap in substrate preference than between them and C. antillensis.621107112Bach, C.B., Hazlett, B., Rittschof, D., Effects of interspecific competition on fitness of the hermit crab Clibanarius tricolor (1976) Ecology, 57, pp. 579-586Barnes, D.K.A., The ecology of tropical hermit crabs at Quirimba Island, Mozambique: Distribution, abundance and activity (1997) Mar. Ecol. Progr. Ser., 154, pp. 133-142Bertness, M.D., Competitive dynamics of a tropical hermit crab assemblage (1981) Ecology, 62 (3), pp. 751-761Forest, J., De Saint Laurent, M., Campagne de la Calypso au large des côtes Atlantiques de l'Amerique du Sud (1961-1962). 6. Crustacés - Décapodes: Pagurides (1967) Annales de L'Institut Océanographique, 45 (2), pp. 47-169Gherardi, F., Competition and coexistence in two Mediterranean hermit crabs Calcinus ornatus (Roux) and Clibanarius erythrops (Latreille) (Decapoda, Anomura) (1990) J. Exp. Mar. Biol. Ecol., 143, pp. 221-238Gherardi, F., Nardone, F., The question of co-existence in hermit crabs: Population ecology of a tropical intertidal assemblage (1997) Crustaceana, 70 (5), pp. 608-629Gherardi, F., Vannini, M., Field observations on activity and clustering in two intertidal hermit crabs, Clibanarius virescens and Calcinus laevimanus (Decapoda, Anomura) (1989) Mar. Behav. Physiol., 14, pp. 145-159Gherardi, F., Vannini, M., Hermit crabs in a mangrove swamp: Clustering dynamics of Clibanarius laevimanus (1992) Mar. Behav. Physiol., 21, pp. 85-104Gherardi, F., Vannini, M., Hermit crabs in a mangrove swamp: Proximate and ultimate factors in the clustering of Clibanarius laevimanus (1993) J. Exp. Mar. Biol. Ecol., 168, pp. 167-187Gilchrist, S., Abele, L.G., Effect of sampling method on the estimation of population parameters in hermit crabs (1984) J. Crust. Biol., 4, pp. 645-654Imazu, M., Asakura, A., Distribution, reproduction and shell utilization patterns in three species of intertidal hermit crabs on a rocky shore on the Pacific coast of Japan (1994) J. Exp. Mar. Biol. Ecol., 184, pp. 41-65Kellogg, C.W., Coexistence in a hermit crab species ensemble (1977) Biol. Bull., 153, pp. 133-144Leite, F.P.P., Turra, A., Gandolfi, S.M., Hermit crabs, gastropod shells, and environmental structure: Their relationship in southeastern Brazil (1998) J. Nat. Hist., 32 (6), pp. 1599-1608Lowery, W.A., Nelson, W.G., Population ecology of the hermit crab Clibanarius vittatus (Decapoda: Duogenidae) at Sebastian Inlet, Florida (1988) J. Crust. Biol., 8 (4), pp. 548-556Melo, G.A.S., (1999) Manual de Identificação dos Crustacea Decapoda do Litoral Brasileiro, , Ed. Plêiade/FAPESP, São Paulo, 551pMitchell, K.A., An analysis of shell ocupation by two sympatric species of hermit crabs. I. Ecological factors (1975) Biol. Bull., 149, pp. 205-213Rebach, S., Burying behavior in relation to substrate and temperature in the hermit crab, Pagurus longicarpus (1974) Ecology, 55, pp. 195-198Reese, E.S., Behavioral adaptations of intertidal hermit crabs (1969) Am. Zool., 9 (2), pp. 343-355Rittschof, D., Sarrica, J., Rubeinstein, D., Shell dynamics and microhabitat selection by striped legged hermit crabs, Clibanarius vittatus (Bosc) (1995) J. Exp. Mar. Biol. 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A Comparative Study Of Intertidal Molluscan Communities In Sandy Beaches, São Sebastião Channel, São Paulo State, Brazil

The aim of this work was to study the molluscan communities in two intertidal environments and their relationship with selected environmental variables. The study areas are located along São Francisco and Engenho d'Agua beaches (São Sebastião Channel, São Paulo State, Brazil). These sites are structurally similar with sediments of coarse sand and pebbles that facilitate settlement of molluscan species. The area was subdivided into low, intermediate and high intertidal levels where the samples were taken. Temperature, salinity, grain size, organic matter, and calcium carbonate content were analyzed as environmental variables. The high species diversity recorded in the study sites was due to the occurrence of organisms on consolidated and unconsolidated substrates. However, differences in the specific composition of the two areas were associated with local differences in sediment constituents and the presence of urban waste water in São Francisco. 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As comunidades bentônicas (1978) Atlântica, 3, pp. 5-22Corbisier, T.N., Benthic macrofauna of sandy intertidal zone at Santos estuarine system, São Paulo, Brasil (1991) Boletim do Instituto Oceanográfico, 39, pp. 1-13Dahl, E., Some aspects of the ecology and zonation of the fauna on sandy beaches (1953) Oikos, 4, pp. 1-27Dexter, D.M., Community structure of intertidal sandy beaches in New South Wales, Australia (1983) Sandy beaches as ecosystems, pp. 461-472. , A. McLachlan and T. Erasmus, eds. Port Elizabeth, South Africa. Dr. W. Junk Publ., The HagueTemporal and spatial variability in the community structure of the fauna of four sandy beaches in south-eastern New South Wales (1984) Aust. J. Mar. Freshw. Res., 35, pp. 663-672Drouin, G., Himmelman, J.H., Béland, P., Impact of tidal salinity fluctuations on echinoderm and mollusc populations (1985) Can. J. 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Temporal Variation In Life-history Traits Of The Clam Tivela Mactroides (bivalvia: Veneridae): Density-dependent Processes In Sandy Beaches

Temporal variation in the structure and dynamics of a population of Tivela mactroides was examined over two periods (2003-2004 and 2007-2008) in the southern part of Caraguatatuba Bay, southeastern Brazil. During the first period from January 2003 to October 2004, sampling was conducted monthly. Sampling in the second period was performed in the summer (January and February 2007 and 2008) and winter (July and August 2007 and 2008). The von Bertalanffy growth function was applied to estimate growth parameters for both periods from length-frequency distributions. Production was determined using the mass-specific growth rate method. Results indicated that the mean abundance (±SE) of T. mactroides varied sharply between the two periods, with an increase of almost 150 times from 2003 to 2004 (8.67·102 ± 0.83·102 ind m-1) to 2007-2008 (1.25·105 ± 3.33·104 ind m-1). The higher abundance in the second period was related to successful recruitment events. While the mean biomass and the production were higher in the second (5.43 ± 0.87 kg AFDM m-1 and 7.89 kg AFDM m-1 yr-1) than in the first period (0.18 ± 0.02 kg AFDM m-1 and 0.18 kg AFDM m-1 yr-1), lower values of shell length, curvature parameter, asymptotic length of the VBGF, and the growth index phi-prime in 2007-2008 (17.57 ± 1.35 mm; K = 0.40 yr-1; L∞ = 38.60 mm, φ{symbol}′ = 2.78) than in 2003-2004 (26.21 ± 1.21 mm; K = 1.00 yr-1; L∞ = 40.75 mm, φ{symbol}′ = 3.22) were related to a strongly density-dependent growth process in the second period. The oscillation in growth observed in the second, but not in the first period also indicates a process of density-dependent growth. These sharp temporal variations in population parameters of T. mactroides suggest the occurrence of density-dependent processes, and reinforce the importance of these processes in structuring sandy-beach populations. © 2013 Elsevier Ltd. All rights reserved

The relictual population of the purple clam Amiantis Purpurata (l.) in northern Patagonia (Argentina): the history of a warm-temperate-water neogene survivor

The purple clam Amiantis purpurata (Lamarck) is a warm-temperate species inhabiting shallow water along the coast from Espiritu Santo (Brazil) to northern Patagonia. It is one of the few survivors of the middle–late Miocene faunal turnover which was characterized by the appearance of new taxa, most of them living now along the Argentinean coast. In order to study the biogeographic history of A. purpurata, a detailed review of its records was carried out. The oldest record of this species is from late Miocene rocks in Uruguay, and it appears that A. purpurata survived because its wide thermal tolerance range allowed larvae to migrate southwards from Uruguay, settling on the southern coast of Buenos Aires Province and San Matías Gulf. The characteristics of this gulf would have favored the development and settlement of the larvae, thus giving rise to the most abundant southern population during the Pleistocene. At the end of the Pleistocene, A. purpurata also survived the Last Glacial Maximum. During the Holocene, the population of A. purpurata in San Matías Gulf became isolated, but also represented the most abundant southern population of this species. During its brief Neogene history, Amiantis purpurata followed main global, regional and local events; thus it can be considered as an environmental indicator for this period.La almeja púrpura Amiantis purpurata (Lamarck) es una especie de aguas templado-cálidas que habita en aguas poco profundas desde Espíritu Santo (Brasil) hasta el norte de Patagonia. Es uno de los pocos sobrevivientes del intercambio faunístico del Mioceno medio–tardío, que se caracterizó por la aparición de nuevos taxa, la mayoría de ellos vivientes en la actualidad a lo largo de la costa argentina. Con el fin de reconstruir su historia biogeográfica, se llevó a cabo una revisión detallada de los registros. El registro más antiguo de A. purpurata proviene del Mioceno tardío en Uruguay, y sobrevivió debido a su amplia tolerancia térmica lo que habría permitido que las larvas migren desde Uruguay hacia el sur, donde se establecieron en la costa sur de la Provincia de Buenos Aires y en el Golfo San Matías. Además, las características de este golfo han impulsado el desarrollo y asentamiento de las larvas, lo que daría lugar a la población más abundante situada más al sur durante el Pleistoceno. Al final del Pleistoceno, A. purpurata también sobrevivió al Último Máximo Glacial y, una vez en el Holoceno, la población de A. purpurata del Golfo San Matías quedó aislada, lo que representa la población más abundante y austral de esta especie. A lo largo de su breve historia geológica durante el Neógeno, Amiantis purpurata acompañó a los principales acontecimientos ocurridos a escala global, regional y local; por lo tanto, esta especie puede ser considerada como un indicador ambiental para este período.Fil: Bayer, María Sol. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Gordillo, Sandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones En Ciencias de la Tierra; ArgentinaFil: Morsán, Enrique . Instituto de Biología Marina y Pesquera Almirante Storni; Argentin