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| Author(s): |
Camila Helena de Souza Queiroz
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB) |
| Defense date: | 2012-07-10 |
| Examining board members: |
Márcio Reis Custódio;
Alexander Turra
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| Advisor: | Márcio Reis Custódio |
| Abstract | |
Sponges are sessile and have a skeleton made of microscopic inorganic elements (spicules), collagen fibers and/or combinations of these two components. Although without clear physical defenses such as shells or spines, they are not preyed upon, and this is attributed mainly to the presence of active secondary metabolites. Recently, a role of skeletal components as deterrents has been experimentally confirmed, but its relative importance is still debated. Some starfishes are regarded as spongivorous, and the existing literature generally considers that the digestion is performed externally, without intake of the sponge skeleton. In this study the feeding behavior of the starfish Echinaster brasiliensis in relation to sponges, the fate of skeletal components and their effects on the starfish physiology were studied. Field observations and laboratory experiments were conducted to determine the consumption strategies used by the starfish. The digestive process of the skeletal material (spicules and/or fibers) was followed until the elimination. It was found that E. brasiliensis feeds on different species of sponges, but does not consume only these organisms, being more generalist than assumed. Preferences in the consumption of sponges were determined by several factors, such as the amount of organic matter or shape of the preyed organism. The intake occurs by the eversion of the stomach, but unlike what is described for other species E. brasiliensis ingests skeletal components, and spicules were found inserted in the digestive epithelium. However, this intake is small and apparently does not cause severe injuries to the starfishes and the spicules are discarded in fecal material (AU) | |
| FAPESP's process: | 09/03392-1 - Strategies and physiology of the consumption and digestion of sponges (Porifera) by Echinaster brasiliensis (Echinodermata) |
| Grantee: | Camila Helena de Souza Queiroz |
| Support Opportunities: | Scholarships in Brazil - Master |