Abstract
The distribution of fertile polyps, and the functional variations of polyps within sea-pen colonies, were investigated in Virgularia juncea, a species inhabiting shallow waters in the Penghu Islands, west of Taiwan. This gonochoristic species started gametogenesis between July and September, and mature gametes were broadcast in late summer the following year. Fertile pinnae and their constituent polyps were located in the middle region of the rachis; the upper and lower regions were infertile. Within the fertile regions, fecundity per centimeter decreased linearly toward the tips of the colonies. Abundant zooxanthellae were found in the upper part of the rachis; algal densities decreased down the axis of the colonies, and no algae were present in the lower part. New pinnae were generated only at the basal part of the rachis, They moved upward in relative position with growth of the colonies. These young pinnae near the peduncle were small and infertile. With time, they became fertile and started to harbor a few zooxanthellae. The old pinnae at the upper part of the rachis were large and infertile and contained numerous zooxanthellae. The tips of the colonies were often damaged, and the bare axial rods there were often fragile and could be easily broken off. The developmental gradient of pinnae (and their constituent polyps) along the axes of the colonies, coupled with the environmental gradient within a sea-pen colony, facilitates the functional differentiation within the rachis that may be an adaptation for inhabiting the interface between the water column and the sediment.
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References
Bayer FM (1973) Colonial organization in octocorals. In: Boardman RS, Cheetham AH, Oliver WA (eds) Animal colonies: development and function through time. Dowden, Hutchinson & Ross, Stroudsburg, Pa., pp 69–93
Birkeland C (1974) Interactions between a sea pen and seven of its predators. Ecol Monogr 44:211–232
Buisson B (1969) Aspects de la régénération chez Veretillum cynomorium (Cnidaria, Pennatulacea). Nat Can (Que) 96:785–797
Chia FS, Crawford BJ (1973) Some observations on gametogenesis, larval development and substratum selection of the sea pen Ptilosarcus guerneyi. Mar Biol 23:73–82
De Ceccatty MP, Buisson B (1965) Reciprocal behavior of the rachis and peduncle in colonies of Veretillum cynomorium Pall. Am Zool 5:531–535
Eckelbarger KJ, Tyler PA, Langton RW (1998) Gonadal morphology and gametogenesis in the sea pen Pennatula aculeata (Anthozoa: Pennatulacea) from the Gulf of Maine. Mar Biol 132:677–690
Franc S, Ledger PW, Garrone R (1985) Structural variability of collagen fibers in the calcareous axial rod of a sea pen. J Morphol 184:75–84
Harrison PL (1985) Sexual characteristics of scleractinian corals: systematic and evolutionary implications. Proc 5th Int Coral Reef Symp 4:337–342
Hyman LH (1940) The invertebrates: Protozoa through Ctenophora. McGraw-Hill, New York
Imafuku M (1976) On the mechanism of the activity rhythm of the sea pen, Cavernularia obesa Valenciennes. Publ Seto Mar Biol Lab 23:1–17
Imafuku M (1980) Activity rhythm of the sea-pen, Cavernularia obesa Valenciennes, under temperature and light cycles. Publ Seto Mar Biol Lab 25: 119–130
Kükenthal WG (1915) Pennatularia. Das Tierrech 43. Friedländer, Berlin
Langton RW, Langton EW, Theroux RB, Uzmann JR (1990) Distribution, behavior and abundance of sea pens, Pennatula aculeata, in the Gulf of Maine. Mar Biol 107:463–469
Rho BJ, Song JI (1976) A study on the classification of the Korean Anthozoa. 1. Gorgonacea and Pennatulacea. Korean Res Inst Better Living 17:71–92
Rice AL, Tyler PA, Paterson GJL (1992) The pennatulid Kophobelemnon stelliferum (Cnidaria: Octocorallia) in the Porcupine Seabight (north-east Atlantic Ocean). J Mar Biol Assoc UK 72:417–434
Soong K (1992) Reproductive integration in reef corals. Biol Bull 183:418–431
Thomson JA, Rennet NI (1927) Report on Japanese pennatulids. J Fac Sci Imp Univ Tokyo Sect IV, Zool 1:115–143
Tyler PA, Bronsdon SK,Young CM, Rice AL (1995) Ecology and gametogenic biology of the genus Umbellula (Pennatulacea) in the North Atlantic Ocean. Int Rev Ges Hydrobiol 80:187–199
Verseveldt J (1983) A revision of the genus Lobophytum von Marenzeller (Octocorallia, Alcyonacea). Rijksmuseum van Natuurlijke Historie, Leiden, The Netherlands
Williams GC (1990) The Pennatulacea of southern Africa (Coelenterata, Anthozoa). Ann S Afr Mus 99:31–119
Williams GC (1992) Biogeography of the octocorallian coelenterate fauna of southern Africa. Biol J Linn Soc 46: 351–401
Wilson EH (1975) Some aspects of the biology of Virgularia mirabilis O.F. Muller (Octocorallia, Pennatulaceae). Master’s thesis, University College of North Wales, Bangor
Acknowledgements
I thank C.-S. Chen, Y.-C. Chen, W.-S. Tsai and the late Y.-W. Huang for help with field and laboratory work. Comments on an early draft from D.L. Ferrell, P. Munguia, E.S. Franke, N.D. Fogarty, M. Adreani, D.R. Levitan and A. Thistle significantly improved the manuscript. This work was supported by the National Science Council, Republic of China in Taiwan (NSC85-2321-B-110-001). The experiments reported here comply with the laws of the Republic of China.
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Communicated by P.W. Sammarco, Chauvin
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Soong, K. Reproduction and colony integration of the sea pen Virgularia juncea. Marine Biology 146, 1103–1109 (2005). https://doi.org/10.1007/s00227-004-1509-1
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DOI: https://doi.org/10.1007/s00227-004-1509-1