A granulometria explica a seleção de habitat de caranguejos chama-marés? um estudo em Leptuca Uruguayensis
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Data
2017-01-19
Autores
Oliveira, Marcelo Wendeborn Miranda de [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
As características granulométricas do sedimento têm sido relatadas como um dos principais fatores determinantes na distribuição dos caranguejos nos manguezais. Os caranguejos chama-marés são importantes representantes por estarem amplamente distribuídos em diferentes frações granulométricas ao longo do estuário e várias espécies serem encontradas coexistindo em um mesmo local, competindo por alimento e espaço. Esse estudo teve como objetivo avaliar a escolha de caranguejos chama-maré por sedimentos com diferentes granulometrias, usando como organismo modelo Leptuca uruguayensis. Em laboratório, terrários com e sem escolhas foram utilizados para avaliar a escolha de caranguejos por três diferentes frações granulométricas (fina, média e grossa). Foram avaliadas a alimentação, o número de tocas escavadas em cada compartimento, se o animal mudou sua escolha ao longo do tempo e se a escolha foi influenciada pela posição em que o animal era solto. Leptuca uruguayensis escolheu o sedimento fino para se alimentar. O consumo de matéria orgânica foi maior no compartimento escolhido para escavar sua toca, do que nos demais, independente do tratamento e dos compartimentos. Os caranguejos construíram apenas uma toca por terrário e escolheram os compartimentos com frações finas para escavar suas tocas. Nossos resultados evidenciam que L. uruguayensis escolhe ativamente sedimento com frações granulométricas menores para forrageamento e escavação de suas tocas.
The sediment granulometric characteristics have been reported as one of the determining factors in the distribution of mangrove crabs. The fiddler crabs are important representatives because they are widely distributed in different granulometric fractions along the estuary and several species are found coexisting and competing for food and space. The purpose of this study was to evaluate the choice of fiddler crabs for sediments with different grain sizes using Leptuca uruguayensis as our model species. In the laboratory, terrariums with and without choices were used to evaluate the choice of crabs for three different granulometric fractions (fine, medium and coarse). We evaluated the feeding behavior, number of burrows excavated in each compartment, whether the animal changed its choice over time and whether the choice was influenced by the position in which animal was released. Leptuca uruguayensis chose finer sediments when feeding. The organic matter consumption was higher in compartments where they excavate their burrows regardless the treatment and compartments. The fiddler crabs built only one burrows per terrarium and also chose compartments with fine fractions to excavate their burrows. Our results showed that L. uruguayensis actively select sediments with smaller particle sizes when foraging and also to excavate their burrows.
The sediment granulometric characteristics have been reported as one of the determining factors in the distribution of mangrove crabs. The fiddler crabs are important representatives because they are widely distributed in different granulometric fractions along the estuary and several species are found coexisting and competing for food and space. The purpose of this study was to evaluate the choice of fiddler crabs for sediments with different grain sizes using Leptuca uruguayensis as our model species. In the laboratory, terrariums with and without choices were used to evaluate the choice of crabs for three different granulometric fractions (fine, medium and coarse). We evaluated the feeding behavior, number of burrows excavated in each compartment, whether the animal changed its choice over time and whether the choice was influenced by the position in which animal was released. Leptuca uruguayensis chose finer sediments when feeding. The organic matter consumption was higher in compartments where they excavate their burrows regardless the treatment and compartments. The fiddler crabs built only one burrows per terrarium and also chose compartments with fine fractions to excavate their burrows. Our results showed that L. uruguayensis actively select sediments with smaller particle sizes when foraging and also to excavate their burrows.
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Distribuição, Escolha, Forrageamento, Escavação tocas, Distribution, Choice, Foraging, Excavation burrows