A sequestered soft coral diterpene in the aeolid nudibranch Phyllodesmium guamensis Avila, Ballesteros, Slattery, Starmer and Paul
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- 作者：Slattery ; Marc ; Avila ; Conxita ; Starmer ; John ; Paul ; Valerie J.
- 关键词：Chemical defenses ; Chemotaxis ; Nudibranch ; Sequestered compounds ; Soft corals
- 刊名：Journal of Experimental Marine Biology and Ecology
- 出版年：1998
- 出版时间：August 1, 1998
- 年：1998
- 卷：226
- 期：1
- 页码：33-49
- 全文大小：182 K
文摘
The aeolid nudibranch Phyllodesmium guamensis Avila, Ballesteros, Slattery, Starmer and Paul, was found actively grazing the soft corals Sinularia maxima (Verseveldt, 1971), S. polydactyla (Ehrenberg, 1834) and S. sp. on Guam. The nudibranchs exhibited a clear chemotactic preference for pieces of the soft corals when compared to control tissues which were extracted of virtually all nonpolar and polar organic metabolites. They also showed soft coral species-specificity for S. maxima. P. guamensis sequesters a diet-derived diterpene 11β-acetoxypukalide selectively within various body parts. Levels were highest in the cerata, with moderate and low to nonexistent levels in the mantle and viscera, respectively. Trace concentrations of the metabolite were also noted in the mucus and egg masses of the nudibranchs. There was no difference in metabolite accumulation in nudibranchs collected at two sites and at the same sites over two years. 11β-acetoxypukalide deters feeding by the pufferfish Canthigaster solandri at a concentration (0.5 % dry mass) approximately an order of magnitude lower than amounts sequestered within the P. guamensis cerata, but concentrations within the mantle and viscera were below threshold feeding deterrent levels. Laboratory and field feeding experiments with nudibranch tissues support these observations, however, the reef fishes tested exhibited species-specific reactions to the nudibranch tissues and their isolated metabolite, which ranged from nondeterrence to emesis. Phyllodesmium guamensis appears to utilize both a cryptic and nocturnal behavior pattern and a sequestered chemical defense to overcome intensive predation pressures on the reefs of Guam.