Chemical defense of Hymeniacidon heliophila (Porifera: halichondrida) against tropical predators

Abstract

Various benthic organisms have chemical defenses which reduce their predators' consumption. Although their efficiency may be noticed in many organisms, many of their effects are not well- known yet. Multiple ecological roles of secondary metabolites are shown in some sponges, which may represent an adaptative advantage considering the high amount of energy used to produce these chemical compounds. The goal of this work was to investigate the defensive property of the extracts from the sponge Hymeniacidon heliophila against the tropical predators: hermit crabs (Calcinus tibicens), sea urchins (Lytechinus variegatus) and generalist fishes. Extracts obtained with n-hexane, ethyl acetate and acetone/methanol were used in assays and all of them were effective in reducing the consumption by C. tibicens; n-hexane extract reduced the consumption by L. variegatus; and medium polarity extracts reduced fish consumption. Either the variation in action or the multiple ecological roles of the extracts indicates that different types of compounds can be associated to the defensive system produced by H. heliophila.<br>Diversos organismos bênticos possuem defesas químicas que ajudam a diminuir a predação. Embora sua eficácia seja comprovada, muitos de seus efeitos são ainda desconhecidos. Múltiplas funções dos metabolitos secundários foram evidenciadas em algumas esponjas e isso pode representar uma vantagem adaptativa, considerando o alto valor energético gasto pelas espécies para produzí-los. O objetivo desse trabalho foi investigar as propriedades defensivas de extratos da esponja Hymeniacidon heliophila contra predadores tropicais: paguros (Calcinus tibicens), ouriços-do-mar (Lytechinus variegatus) e peixes generalistas. Extratos em n-hexano, acetato de etila e acetona/metanol foram usados nos ensaios e todos foram eficientes na redução do consumo por C. tibicen; extratos em n-hexano reduziram o consumo por L. variegatus; e extratos de média polaridade reduziram o consumo por peixes. A variação na ação ou as funções ecológicas múltiplas dos extratos indicam que diferentes tipos de substâncias podem ser associadas ao sistema defensivo produzido por Hymeniacidon heliophila

Antifouling activity of twelve demosponges from Brazil

“…The effectiveness of H. heliophila crude extract from Rio de Janeiro should represent an important ecological advantage, since this sponge occurs in the same zone of P. perna and is usually found living over them. Moreover, antipredation activity against fishes, sea urchins and hermit crabs had been demonstrated in extracts from H. heliophila (Ribeiro et al, 2010). On the other hand, field and laboratory experiments differ in several aspects, making hard direct comparisons.…”

Toxicity evaluation of PAHs in the sponge Hymeniacidon heliophila: field assessment and laboratory assays - a preliminary study

“…Overwall, it is difficult to connect biological responses to a certain exposure and also take into account individual variability. Sponges are organisms with high microbial activity, particular cellular characteristics, and an intricate secondary metabolism (Vogel, 1977;Muricy & Hajdu, 2006;Ribeiro et al, 2010;Turque et al, 2010), which, added to their tissue structure, result in high complexity, which poses an additional obstacle to the understanding of sponge processes and their association to chemical contamination.…”

Calcareous spherules produced by intracellular symbiotic bacteria protect the sponge Hemimycale columella from predation better than secondary metabolites

“…Many of the bioactive compounds produced by sponges with antimitotic, cytotoxic, antibacterial, and/or antitumor activities (Amade et al 1987, Uriz et al 1992, Becerro et al 1994, Monks et al 2002, Sipkema et al 2005, Blunt et al 2009, Hardoim & Costa 2014 inhibit the settlement of foreign larvae in the proximity of the sponge (Martin & Uriz 1993, Becerro et al 1997a, De Caralt et al 2013 or deter predation (Uriz et al 1996, Ribeiro et al 2010, Arias et al 2011. Spicules have also been reported to dissuade sponge predators to some extent (Burns & Ilan 2003, Hill et al 2005, Jones et al 2005, but see Chanas & Pawlik 1995).…”