Differential feeding strategies in phyllidiid nudibranchs on coral reefs at Halmahera, northern Moluccas
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KeywordsSponge Coral Reef Tropical Coral Feeding Apparatus Feeding Technique
During a biodiversity survey off West Halmahera (northern Moluccas) in 2009, we recorded seven phyllidiid species on six halichondrid species. Sponges were identified by the second author (NJdV). Vouchers are deposited in NCB Naturalis. Phyllidia varicosa, Phyllidiella pustulosa, and Phyllidiella nigra fed almost exclusively on the same sponge host, Axinyssa aff. variabilis (Fig. 1a), however, using different feeding techniques. P. varicosa feeds superficially, consuming little more than its host’s skin, often leaving a pattern of multiple discoloured, rosette-shaped marks (Fig. 1c). In contrast, P. pustulosa inserts its exceptionally large pharyngeal bulb deep into the host sponge, frequently creating a narrow hole as deep as half its own length (Fig. 1d). Finally, P. nigra, which has a pharyngeal bulb similar to that of P. pustulosa, yet not quite as large, appears to consume consecutive chunks of tissue from the host’s surface; in one instance, little of the exposed surface was left untouched (Fig. 1e). Dissection of two specimens of each species revealed a significant amount of whole spicules belonging to Axinyssa aff. variabilis in the digestive tracts of P. nigra and P. pustulosa, but not in P. varicosa.
In conclusion, P. varicosa, P. pustulosa, and P. nigra differ in the way they exploit their mutual host, and this difference may facilitate their coexistence in species-rich coral reefs.
The survey was sponsored by the Research Centre for Oceanography, Indonesian Institute of Sciences (PPO-LIPI), and funded by the J. J. ter Pelkwijk Fund, the Martin Foundation, and the A.M. Buitendijk Fund. The research permit was issued by the Indonesian State Ministry of Research and Technology (RISTEK).
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- Cimino G, Ghiselin MT (2009) Chemical defense and the evolution of opisthobranch gastropods. Proc Calif Acad Sci 60:175–422Google Scholar