Prudent sessile feeding by the corallivore snail, Coralliophila violacea on coral energy sinks

Abstract

Convergence of form and function has accompanied the evolution of modular growth in terrestrial plants and colonial marine invertebrates. Part of this convergence is related to the optimal exploitation of resources (space and light) and the ability to translocate energy products from sources to sink sites. Feeding on the energy pathways and energy sinks of terrestrial plants is a well-known phenomenon. Hermatypic corals, the major organisms constructing tropical reef environments, contain photosynthetic algae (zooxanthellae), energetic products of which are translocated towards sink sites located at the corals' growing tips and regenerating areas. Despite the plant^coral convergence in energy pathways and sinks, there has been no evidence to date that coral energy sinks are exploited by coral predators. Gastropods of the genus Coralliophila are found feeding on coral margins, causing small and localized tissue damage. However, the ability of these snails to continue to feed without moving over a long period remains puzzling. Using a 14 C labelling technique, we found that colony margins of the stony coral Porites function as major energy sinks. When snails inhabited these sites they incorporated signi¢cant amounts of 14 C, indicating that they had fed on photosynthetic products translocated from the interior of the colony. Furthermore, when snails aggregate in the interior of the colony, thereby causing large surface injuries, they induce the development of signi¢cant new sink sites. This mode of prudent sessile feeding maximizes the e¤ciency of energy exploitation by the predatory snail, while minimizing tissue damage to the coral. The fact that energy sink sites occur in many coral species suggests that the strategy of sink exploitation for nutrition could also occur in many other marine host^symbiont relationships.

Locally accelerated growth is part of the innate immune response and repair mechanisms in reef-building corals as detected by green fluorescent protein (GFP)-like pigments

“…This process explains the ''swelling'' of highly pigmented Porites tissue in contact with Coralliophila sp. or the formation of nodules around encysted trematodes (Oren et al 1998;Aeby 2003) as attempts of the coral to neutralize xenobionts by encapsulation (ESM Fig. 6).…”

Tasa de depredación de Coralliophila abbreviata (Neogastropoda: Coralliophilidae) sobre algunas especies coralinas del Parque Nacional Morrocoy, Venezuela

“…Este comportamiento ha sido registrado en C. violacea (Kiener 1836) por Oren et al (1998), quienes definieron esta estrategia depredadora como "alimentación sésil prudente" y explicaron que los bordes de las lesiones en las colonias coralinas pueden comportarse como sumideros energéticos que son aprovechables por el depredador. Estos autores encontraron mayor actividad de elementos fotosintéticos en los márgenes de las colonias de Porites lobata (Dana, 1846) en comparación con la zona interior de la misma cuando C. violacea realizó su actividad depredadora.…”

“…Estos autores encontraron mayor actividad de elementos fotosintéticos en los márgenes de las colonias de Porites lobata (Dana, 1846) en comparación con la zona interior de la misma cuando C. violacea realizó su actividad depredadora. Este comportamiento maximiza la eficiencia de la explotación energética por parte del depredador y minimiza el daño sobre el tejido coralino, además de proteger a Coralliophila de sus respectivos depredadores, debido a que el crecimiento de algas oculta al molusco (Oren et al 1998, Brawley & Adey 1982.…”

“…Van Alstyne y Paul (1992) señalan que el género octocoralino Gorgonia presenta un gradiente en las concentraciones de metabolitos secundarios desde la zona más distal de la colonia hasta su base. -Diferencias interespecíficas en zonas de mayor translocación energética (Oren et al 1998) que se traducen en un diferencial en el comportamiento depredador de C. abbreviata en función de cada especie coralina, por lo que el depredador se localiza en distintos sumideros energéticos. -Diferencias en exposición y vulnerabilidad de C. abbreviata a ser depredada por sus respectivos depredadores Baums et al (2003) indican que las diferencias en las morfologías de las especies coralinas Acropora palmata y M. annularis pueden proveer diferencias en la calidad de refugio para los moluscos en defensa de sus depredadores.…”

Coralliophila from Grand Cayman: Specialized coral predator or parasite?

“…Coralliophila abbreviata rapidly consumes coral tissues causing substantial colony mortality. Coralliophila violacea remains sedentary and taps into coral energy reserves, a ''prudent'' sessile feeding strategy that allows the snails to feed without moving over long periods, maximizing energy exploitation while minimizing coral damage and mortality (Oren et al 1998).…”