invemar
todos por un nuevo pais - minambiente
SiAMSistema de Información Ambiental Marina

Explore la biodiversidad

Detalle de Documento

  • Defenses of Caribbean sponges against predatory reef fish. I. Chemical deterrency

    Autor(es): Pawlik, Joseph R.[... et al.]

    Ubicación: Centro de Documentación INVEMAR

    Solicítelo como: EE-33738

    Palabras clave: Esponjas, Arrecifes coralinos, Mecanismos de defensa, Depredación

Laboratory feeding assays employing the common Caribbean wrasse Thalassoma bifasciatum were undertaken to determine the palatability of food pellets containing natural concentrations of crude organic extracts of 71 species of Caribbean demosponges from reef, mangrove, and grassbed habitats. The majority of sponge species (69 percent) yielded deterrent extracts, but there was considerable inter - and instraspecific variability in deterrency. Most of the sponges of the aspiculate orders Verongida and Dictyoceratida yielded highly deterrent extracts, as did all the species in the orders Hadromerida, Poecilosclerida and Haplosclerida. Intraspecific variability was evident evident, suggesting that, form some species, some individuals (or portions thereof) may chemically undefended. Reef sponges generally yielded more deterrent extracts than sponges from mangrove or grassbed habitats, but 4 of the 10 most Common sponges on reefs yielded palatable extracts (Callyspongia vaginalis, Mycale leavis, Niphates erecta, Iotrochota birulata), including those most commonly eaten by sponge-eating reef fish. The presence of symbiotic zoanthid cnidarians of the genus Parazoanthus in the tissues of the otherwise palatable sponges had little effect on the deterrency of tissue extracts, indicating that these commensal polyps do not confer a chemical defense by association. There was no relationship between sponge color and deterrency, suggesting that sponges are not aposematic and that color variation is the result of other factors. There was also no relationship between the toxity of sponge extracts (as determined in previous studies) and deterrency, confirming the invalidity of previous assessments of chemical defense based toxicity. Although chemical antipredatory defenses are important strategies for most Caribbean sponges, some common species appear to rely on other tactics.