or that it may have preyed on small epibionts on the worm's peduncle. The present ... The invasive sun coral Tubastraea coccinea hosting a native Christmas.
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BULLETIN OF 93(4):000–000. MARINE SCIENCE. 00(0):000–000. 0000 Bull Mar Sci. 2017 doi:10.5343/ https://doi.org/10.5343/bms.2017.1059
Attack on a Christmas tree worm by a Caribbean sharpnose pufferfish at St. Eustatius, Dutch Caribbean BW Hoeksema 1, 2 *, HA ten Hove 1 Naturalis Biodiversity Center, P.O. Box 9517, 2300 RA Leiden, Netherlands. Institute of Biology Leiden, Leiden University, P.O. Box 9505, 2300, RA Leiden, Netherlands. * Corresponding author email: . 1
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Christmas tree worms are polychaetes of the genus, Spirobranchus (Serpulidae). These reefdwelling species live inside tubes that are usually embedded inside the skeletons of corals belonging to either the order Scleractinia (Anthozoa) or to the family Milleporidae (Hydrozoa) (Hoeksema and Ten Hove 2017, Perry et al. 2017). Extended Spirobranchus worms are visible because of their large, bright-colored branchiae, shaped as twin spirals, and a peduncle (stalk) with a calcified spiny operculum on top. Their colormorph variation and the presence of long spines on the tube may serve as protection against predators (Grassle 1973). When in danger, the worms are able to retract quickly inside their tube, while using their operculum as a shield (Hoeksema et al. 2016, Pezner et al. 2017). Although little is known about predators of Spirobranchus spp. and no actual attacks have been documented (Kupriyanova et al. 2001), predation has been inferred from damaged and/or missing opercula in about 10% of the examined specimens [Nishi and Kikuchi 1996 for Spirobranchus corniculatus (Grube, 1862)]. In addition, Randall (1967) recorded 30%–59% of the gut content of butterfly fishes to consist of “tentacular crowns of serpulids, sabellids and terebellids.” Furthermore, many worm tubes can be found in which the original worm has disappeared and been replaced by the spinyhead blenny, Acanthemblemaria spinosa Metzelaar, 1919 (Chaenopsidae) (Böhm and Hoeksema 2017). This can also be a sign of worm predation because coral-dwelling worms are otherwise known to be long-lived (Nishi and Nishihira 1996). Bulletin of Marine Science
© & Atmospheric ©2017 2011Rosenstiel RosenstielSchool School of Marine and AtmosphericScience Scienceof the University ofof Miami of the University Miami
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Two Caribbean Spirobranchus species are known as common associates of scleractinian corals and fire corals in reef environments, i.e., Spirobranchus giganteus (Pallas, 1766) and Spirobranchus polycerus (Schmarda, 1861) (Hoeksema and Ten Hove 2017, references herein). Spirobranchus giganteus is the largest, and the brightest and most variable in coloration of the two. Both species were found co-occurring in a colony of Porites astreoides Lamarck, 1816 (Panel A) at 4 m depth on remnants of the submerged city wall of the Dutch Caribbean island, St. Eustatius (17°28´56.3˝N, 62°59´20.3˝W). Because of the shallow depth and exposure to waves, the branchiae of the worms swayed continuously (Panel B), which may have made them hyposensitive and under-responsive to other disturbances. When a Caribbean sharpnose puffer, Canthigaster rostrata (Bloch, 1786) (Tetraodontidae), bit at the peduncle of the red S. giganteus, the worm did not retract (Panel C) and remained unharmed. Caribbean sharpnose puffers have a long snout and large fused front teeth, suitable for picking at prey (Panel D). They are omnivorous and their diet may consist of mollusks, crustaceans, sea urchins, and polychaete worms (Randall 1996). The lack of visible injury may indicate that the fish was discouraged to bite through when it felt the worm’s spiny operculum or that it may have preyed on small epibionts on the worm’s peduncle. The present report shows the rarely documented co-occurrence of two Spirobranchus species, a fish attack on the largest and most colorful specimen, and the negligence of the worms to retract in a turbulent environment despite the risk of predation. Examination of the gut contents of pufferfish may reveal whether they actually do prey on serpulids and whether prey color is important herein. Experiments may show whether mechanical overstimulation of Spirobranchus worms affects their retraction behavior. Acknowledgments We thank St. Eustatius Marine Parks (STENAPA), Caribbean Netherlands Science Institute (CNSI), and Scubaqua Dive Centre for providing logistic support. We want to thank the editor and three anonymous reviewers for their constructive comments. Literature Cited Böhm T, Hoeksema BW. 2017. Habitat selection of the coral-dwelling spinyhead blenny, Acanthemblemaria spinosa, at Curaçao, Dutch Caribbean. Mar Biodivers. 47:17–25. https://doi.org/10.1007/s12526-0160543-9 Grassle JF. 1973. Variety in coral reef communities. In: Jones OA, Endean R, editors. Biology and geology of coral reefs 2. Biology 1. New York: Academic Press. p. 247–270. Hoeksema BW, Ten Hove HA. 2017. The invasive sun coral Tubastraea coccinea hosting a native Christmas tree worm at Curaçao, Dutch Caribbean. Mar Biodivers. 47:59–65. https://doi.org/10.1007/s12526016-0472-7 Hoeksema BW, Ten Hove HA, Berumen MI. 2016. Christmas tree worms evade smothering by a coralkilling sponge in the Red Sea. Mar Biodivers. 46:15–16. https://doi.org/10.1007/s12526-015-0339-3 Kupriyanova EK, Nishi E, Ten Hove HA, Rzhavsky AV. 2001. Life-history patterns in serpulimorph polychaetes: ecological and evolutionary perspectives. Oceanogr Mar Biol Annu Rev. 39:1–101. Nishi E, Kikuchi T. 1996. Preliminary observation of the tropical serpulid Spirobranchus giganteus corniculatus Pallas. Publ Amakusa Mar Biol Lab Kyushu Univ. 12:45–54. Nishi E, Nishihira M. 1996. Age-estimation of the Christmas tree worm Spirobranchus giganteus (Polychaeta, Serpulidae) living buried in the coral skeleton from the coral-growth band of the host coral. Fish Sci. 62:400–403. http://dx.doi.org/10.2331/fishsci.62.400 Perry O, Sapir Y, Perry G, Ten Hove H, Fine M. 2017. Substrate selection of Christmas tree worms (Spirobranchus spp.) in the Gulf of Eilat, Red Sea. J Mar Biol Assoc UK. https://doi.org/10.1017/ S0025315416002022 Pezner AK, Lim AR, Kang JJ, Armenta TC, Blumstein DT. 2017. Hiding behavior in Christmas tree worms on different time scales. Behav Ecol. 28:154–163. https://doi.org/10.1093/beheco/arw140 Randall JE. 1967. Food habits of reef fishes of the West Indies. Studies in Tropical Oceanography. Miami: University of Miami. No. 5. p. 665–847. Randall JE. 1996. Caribbean reef fishes. 3rd ed. Hong Kong: T.F.H. Publications.
Date Submitted: 15 May, 2017. Date Accepted: 30 June, 2017. Available Online: 14 July, 2017.
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