Anti-predation defense of the sponge Mycale (Zygomycale) angulosa (DUCHASSAING & MICHELOTTI, 1864) against different predators T. S.B. Reppso, J. M. Araujo, A. L.D. Lopes, G. Lobo-Haidu, B. G. Fleury

Abstract

Porifers present a high diversity and abundance of species in marine communities, playing important roles in maintaining biodiversity and structuring the ecosystem, in addition to presenting important sources of biologically functional natural products. The ecological activities of natural products found in sponges, such as the Mycale genus, are very diverse, including the production of chemical defense against predators. In this context, there are models that attempt to explain the distribution and abundance of species in the environment, such as the Optimal Defense Model (ODM) which predicts that defenses can be induced through predation pressure. Mycale (Zygomycale) angulosa (Duchassaing & Michelotti, 1864) has a wide geographic distribution, however there are few studies of defensive activity with an emphasis on natural products. Therefore, the objective of this study was to evaluate the chemical defense of M. angulosa against predation by different types of consumers (small and highly mobile). The study was carried out with M. angulosa collected in Abraãozinho, Ilha Grande, RJ. The sponges were freeze-dried and extracted with DCM organic solvent. The crude extract (EB) was tested in the laboratory for predation by the crab Pachygrapsus transversus , and against generalist fish in situ, in Abraãozinho. Control foods were simultaneously offered (crab: agar+squid powder/fish: carrageenan+tuna puree), and treatment (agar+EB+squid powder/fish: carrageenan+EB+tuna puree). Consumption in both trials was evaluated through the percentage difference between controls and treatments offered, in each replication using the non-parametric Wilcoxon paired test (Statistica 7). Being significant when p<0.05 . The M. angulosa extract inhibited consumption by crabs in the predation bioassay ( p <0.01; n=30), and consumption by fish in situ ( p<0.01 ; n=28). It was concluded, therefore, that M. angulosa presents a highly effective chemical defense strategy, being defended against different types of consumers. This result suggests that the strategy used by M. angulosa can be induced by the predation pressure suffered in the environment, corroborating the MDO. Therefore, the defense metabolites of M. angulosa guarantee the survival and abundance of the species in the environment.