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El cangrejo violinista Leptuca uruguayensis tiene como límite sur de su distribución geográfica la provincia de Buenos Aires, Argentina, donde la temporada reproductiva es corta. El objetivo de esta tesis fue estimar el esfuerzo reproductivo y comprender la estrategia de inversión energética que poseen las hembras de esta población en un estuario templado. En primer lugar, se estudió el patrón reproductivo de L. uruguayensis con una aproximación experimental en campo y laboratorio. Se registraron el tamaño de las hembras, el tiempo de incubación, el número de puestas que tienen y el tiempo entre las mismas. Luego, se evaluó la variación del estadio de desarrollo del ovario y el volumen del ovario y del hepatopáncreas a lo largo de la temporada reproductiva. Además, se analizaron las reservas en estos órganos mediante análisis bioquímicos. Esto permitió reconocer en la temporada reproductiva tres momentos, en cada uno de los cuales se registró un evento de puesta en la población. Debido a que las hembras de esta especie atraviesan dos temporadas reproductivas como adultas, se determinó que en el primer ciclo reproductivo, las hembras medianas y chicas pueden tener como máximo una puesta, mientras que, en el segundo ciclo reproductivo de sus vidas, las hembras grandes pueden tener hasta dos puestas. Además, se evidenció que las hembras emplean una estrategia reproductiva mixta en el manejo de la energía para la reproducción. Para conocer si el desempeño reproductivo de las hembras se modifica a lo largo de su vida, se evaluaron variables reproductivas teniendo en cuenta el ciclo reproductivo que atraviesan las hembras y el momento de la temporada reproductiva. Si bien las hembras de primer ciclo reproductivo mostraron menor fecundidad, el rendimiento reproductivo fue similar para todas las hembras, en todos los momentos de la temporada reproductiva. El volumen del huevo y los carotenoides se vieron afectados por los momentos de la temporada reproductiva y, la calidad nutricional de los huevos, por el ciclo reproductivo de la hembra. Debido a que se observó que sólo las hembras grandes son capaces de tener dos puestas en la misma temporada reproductiva, se evaluó la dinámica energética y el desempeño reproductivo de éstas. Se comprobó que las hembras grandes tienen la primera puesta de la temporada reproductiva utilizando mayoritariamente la estrategia de capitalización. Dos meses más tarde, tienen la segunda puesta utilizando en mayor medida la estrategia reproductiva de uso inmediato, mediante el incremento de la ingesta de energía evidenciado por el aumento en la tasa de alimentación. Las puestas de huevos producidas por las hembras en la primera puesta mostraron mayor fecundidad y peso que aquellas puestas que fueron producidas en la segunda puesta. Sin embargo, la energía asignada por las hembras grandes de L. uruguayensis a cada embrión fue similar en ambas puestas. Los resultados de este trabajo evidencian cómo las hembras de L. uruguayensis utilizan la energía disponible cuando la ventana de condiciones óptimas para reproducirse es estrecha, aplicando una estrategia reproductiva mixta que maximiza el uso de recursos asegurando un proceso reproductivo exitoso. The southern limit of the geographical distribution of the fiddler crab Leptuca uruguayensis is in the province of Buenos Aires, Argentina, where the reproductive season is short. The aim of this thesis was to estimate the reproductive effort and to understand the energy investment strategy displayed by the females of this population in a temperate estuary. First, the reproductive pattern of L. uruguayensis was studied with an experimental approach in the field and in the laboratory. The size of the females, brooding time, number of spawns, and time between spawns, were recorded. Also, the variation of the developmental stage of the ovary and the volume of the ovary and hepatopancreas throughout the reproductive season were evaluated. In addition, the reserves in these organs were studied by biochemical analyses. Three periods in the reproductive season were recognized, with a population spawning event recorded in each one. Since the females of this species go through two reproductive seasons as adults, it was determined that in the first reproductive cycle, the medium and small females can have a maximum of one spawn, while during the second reproductive cycle of their lives, the larger females can have up to two spawns. In addition, it was evidenced that females use a mixed reproductive strategy in managing energy for reproduction. To determine whether the reproductive performance of females is modified throughout their lives, reproductive traits were evaluated considering the reproductive cycle of females and the period of the reproductive season. Although females in the first reproductive cycle showed lower fecundity, reproductive performance was similar for all females, at all periods of the reproductive season. Egg volume and carotenoids were affected by the periods of the reproductive season, whereas egg nutritional quality, by the female reproductive cycle. Since only large females can have two clutches in the same reproductive season, their energetic dynamics and reproductive performance were evaluated. Large females have the first spawn of the reproductive season using mostly the capital breeding strategy. Two months later, they have the second spawn increasing the using of the income breeding strategy, through increased energy intake, evidenced by increased feeding rate. Egg clutches produced by females in the first spawn showed higher fecundity and weight than clutches produced in the second spawn. However, the energy allocated by large females of L. uruguayensis to each embryo was similar for both strategies. The results of this thesis evidence how the females of L. uruguayensis use the available energy when the optimal reproduction window is narrow, applying a mixed reproductive strategy that maximizes the use of resources, ensuring a successful reproductive process. Fil: Marciano, Agustina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.

Reproduction is a costly process that depends on the management of available resources. Here, we aimed to understand the energetic strategies of females of the fiddler crab Leptuca uruguayensis (Nobili, 1901) in a population with short reproductive seasons. For this, we developed an integrated approach to recognize the brooding time, spawning pattern modulated by female size, number of spawns per female, and content of reserves in the ovary and hepatopancreas. Based on the condition of the ovary and hepatopancreas, the reproductive season was divided into three periods. In each of these periods, it was possible to record a spawning event, which was mainly represented by large females. Most of the females had one spawn during the breeding season, and only large females had two spawns, with an interval of approximately 2 months. We propose that L. uruguayensis presents a mixed capital–income breeding strategy associated with the female size and period of the reproductive season. We conclude that large females make the greatest reproductive effort for the population because they can have two spawns, whereas medium-sized and small females make a low contribution because they are still investing energy in somatic growth to increase fecundity in the next reproductive season.

Made available in DSpace on 2018-12-11T17:21:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-11-15 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Fiddler crabs are a key benthic macrofauna group in estuarine environments. Species distribution is determined by relatively distinct zones, based on biotic and abiotic factors. As sediment organic matter is thought to be one of the most important zoning factors of mangrove macrofauna, we tested the effects of organic matter content on the intra-specific distribution of the fiddler crabs Leptuca thayeri and Leptuca uruguayensis. Organic matter content and crab abundance and size were assessed in both species by field observations, while the choice of adult or juvenile L. uruguayensis for high -or low- organic matter was tested in the laboratory. Both species showed no relationship between organic matter and crab abundance or size. Furthermore, L. uruguayensis juveniles or adults did not show any preference for specific organic matter content. Therefore, fiddler crabs intra-specific distribution in mangrove forests is not dependent of the water-land gradient decrease of organic matter. Postgraduate Program in Biological Sciences (Zoology) Botucatu Biosciences Institute São Paulo State University – UNESP Center of Natural and Human Sciences Federal University of ABC (CCNH/UFABC) Biosciences Institute São Paulo State University (UNESP), Coastal Campus Postgraduate Program in Biological Sciences (Zoology) Botucatu Biosciences Institute São Paulo State University – UNESP Biosciences Institute São Paulo State University (UNESP), Coastal Campus FAPESP: #2014/00456-7

A comparative study on size and shape of Leptuca uruguayensis was carried out between populations from Garças River, Brazil (BP), and Solís Grande River, Uruguay (UP). The size of the onset of sexual maturity was also estimated for UP. A total of 36 crabs BP and 387 crabs UP were analyzed. In the relative growth analysis, carapace width (CW) for both sexes, major cheliped length (LMC) for males and abdomen width (AW) for females were measured. The centroid size of carapace (1.40±0.19 cm BP and 1.88±0.30 cm UP) and cheliped (1.16±0.22 cm BP and 1.58±0.45 cm UP) differed significantly (p

The southernmost permanent population of the fiddler crab Leptuca uruguayensis occurs along the Samborombón Bay (36°22′S, 56°45′W, Argentina), an important feeding site for many bird species, including ruddy turnstones (Arenaria interpres), whimbrels (Numenius phaeopus), grey plovers (Pluvialis squatarola), american golden plovers (Pluvialis dominica) and gull-billed terns (Gelochelidon nilotica). Although all these birds are known to prey on many fiddler crab species worldwide, there is no estimation of their joint predation impacts, probably due to the difficulty in conducting experiments on an appropriate spatial scale. In these situations, computer simulation methods are useful tools. By using Monte Carlo methods and field data, we modeled the decrease of a fiddler crab population due to bird predation. The model found that under current bird occurrences and crab densities, birds do not consume more than 0.03% of the studied fiddler crab populations. Birds only consume more than 10% of the population if crab density is below 0.02 crabs m2, or if bird occurrences are at least 3 orders of magnitude higher than currently observed. Both situations are unlikely, as mean crab density is 140 crabs m2, and bird density is never so high. Furthermore, by monitoring three different fiddler crab patches, we found that bird predation cannot account for temporal density changes, suggesting that other population processes are more important than bird predation. In conclusion, even though fiddler crabs may exhibit strong predator-Avoidance behavior, direct lethal effects of bird predation are currently small. Fil: Ribeiro, Pablo Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Navarro, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Jaureguy, Luciano M.. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; Argentina Fil: Daleo, Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Iribarne, Oscar Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

The occurrence of the fiddler crab Leptuca (=Uca) uruguayensis (Brachyura: Ocypodidae) in the Bahía Blanca Estuary (Buenos Aires, Argentina) is reported for the first time. The organisms had a small patchy distribution with high densities in an environment with silty-sandy sediments and low organic matter content, near the population of the dominant varunid crab Neohelice granulata. The presence of this species suggests that larvae of L. uruguayenesis may have been introduced into the estuary via the ballast water of ships. The field sampling was extended to other sites closer to this harbour to assess if the species was inhabiting other places within the estuary, but with no results. Within this framework, the monitoring of this population is fully recommended; moreover, it is necessary to keep monitoring other sites in order to assess if this species could settle in other places in the future. Fil: Truchet, Daniela María. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina Fil: Buzzi, Natalia Sol. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina Fil: Carcedo, Maria Cecilia. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina Fil: Marcovecchio, Jorge Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Tecnológica Nacional. Facultad Regional Bahía Blanca; Argentina

Made available in DSpace on 2020-12-12T02:19:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-11-01 Universidade Estadual Paulista Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Climate change is drastically altering environmental conditions and resource availability. Many organisms are shifting their distribution boundaries. Fiddler crabs, for instance, are important ecosystem engineers in coastal environments that have been extending their distribution range poleward. In this study, we evaluated the influence of a range-extending species, Leptuca cumulanta, which has recently overlapped the distribution of the resident species Leptuca uruguayensis. Through a set of field and laboratory experiments, we characterised the degree of territorial overlap between L. cumulanta and L. uruguayensis from the lower to upper intertidal zone in a mangrove area. We also analysed whether the presence of L. cumulanta prevents habitat choosiness or influences agonistic behaviours in L. uruguayensis in territorial fights. We found that both species overlap territories at the same level in the intertidal zone. However, we observed that both habitat choice and agonistic behaviours of L. uruguayensis were unresponsive to the presence of L. cumulanta. The low interference between recent heterospecific neighbours sharing the same space supports coexistence of fiddler crabs L. uruguayensis and L. cumulanta in the early stage of overlapping. Biosciences Institute São Paulo State University (UNESP), Coastal Campus Postgraduate Program in Biological Sciences (Zoology) Biosciences Institute São Paulo State University (UNESP) University of Agder (UiA) Center for Coastal Research Norwegian Institute for Water Research (NIVA), Jon Lilletuns vei 3 Institute of Marine Science Federal University of São Paulo (IMar/UNIFESP) Aquaculture Center (CAUNESP) São Paulo State University (UNESP), Jaboticabal Biosciences Institute São Paulo State University (UNESP), Coastal Campus Postgraduate Program in Biological Sciences (Zoology) Biosciences Institute São Paulo State University (UNESP) Aquaculture Center (CAUNESP) São Paulo State University (UNESP), Jaboticabal FAPESP: #2015/50300-6