Effects of sponge and barnacle encrustation on survival of the scallop Chlamys hastata
- 249 Downloads
The scallop Chlamys hastata frequently carries epibionts such as sponges and barnacles on its shells. Although the scallop-sponge relationship has been characterized as a mutualism, little is known about the scallop-barnacle relationship. This study investigated the effects of sponge and barnacle encrustation on the ability of C. hastata to avoid predation by the sea star Pycnopodia helianthoides. In feeding trials, P. helianthoides caught and consumed significantly more barnacle-encrusted scallops (7.7 ± 0.8 out of 20 scallops) than scallops encrusted by either of the sponges Myxilla incrustans (4.1 ± 0.9) or Mycale adhaerens (3.0 ± 0.5). Epibiont-free scallops (5.7 ± 0.5) formed an intermediate treatment between barnacle-encrusted and sponge-encrusted scallops. Possible mechanisms by which the sponges protected the scallops were investigated in two ways: two feeding trials were videotaped to allow qualitative analysis of sea star and scallop behavior and sea star feeding responses to scallop and sponge homogenates were determined to investigate if sea stars accept scallops and sponges as prey. Sea stars displayed positive feeding responses to scallop puree 97.5% ± 1.6 of the time while only displaying positive responses to Mycale adhaerens homogenate 4.4% ± 2.0 of the time and to Myxilla incrustans homogenate 4.4% ± 2.9 of the time. The videotaped feeding trials indicated that interference with tube feet adhesion by the sponge deterred predation. Observations of both sea stars that were videotaped showed that neither avoided trying to capture sponge-encrusted scallops, and at no time was a captured scallop willingly released by the sea stars. Thus, it appears that sponges provide tactile-mechanical protection and possibly chemical or tactile camouflage in this predator/prey relationship. Finally, the effects of sponge encrustation on barnacle settlement were determined. Field experiments showed that barnacle larvae settled more frequently on epibiont-free scallops than on those with either of the two sponges, potentially protecting the scallops from an epibiont that increases the scallop’s susceptibility to predation.
KeywordsScallop Sea star Epibiont Predator-prey interactions Associational resistance Share-doom
We wish to thank the faculty and staff at Shannon Point Marine Center for research space and support, and the Anacortes Marina for providing dock space for the field experiment. Brian Bingham, Gene McKeen, Giséle Muller-Parker, and Nathan Schwarck helped immensely with scallop collection. Sandra Caldwell and Patrick Gloman assisted with data collection. The barnacles that settled on the caged scallops were identified by Dr. William Newman at Scripps Oceanographic Institute. Dr. Tom Carefoot, Dr. James McClintock, and an anonymous reviewer provided helpful feedback on various drafts of the manuscript.
- Amsler, C. D., J. B. McClintock & B. J. Baker, 1999. An Antarctic feeding triangle: defensive interactions between macroalgae, sea urchins, and sea anemones. Marine Ecology Progress Series 183: 105–114.Google Scholar
- Breen, P. A., 1979. Selective feeding of the sunflower star, Pycnopodia helianthoides, in the laboratory. Fisheries and Marine Service Manuscript Report 1498: 10 pp.Google Scholar
- Conover, W. J., 1999. Practical Nonparametric Statistics, 3rd edn. Wiley and Sons, NY.Google Scholar
- Donovan, D. A., B. L. Bingham, H. M. Farren, R. Gallardo & V. Vigilant, 2002. The effect of sponge encrustation on the swimming behavior, energetics, and morphometry of the scallop Chlamys hastata (Sowerby). Journal of the Marine Biological Association of the United Kingdom 82: 469–476.CrossRefGoogle Scholar
- Donovan, D. A., B. L. Bingham, M. From, A. F. Fleisch & E. S. Loomis, 2003. Effects of barnacle encrustation on the swimming behaviour, energetics, morphometry and drag of the scallop Chlamys hastata. Journal of the Marine Biological Association of the United Kingdom 83: 813–819.CrossRefGoogle Scholar
- Hills, J. M. & J. C. Thomason, 1998. The effect of scales of surface roughness on the settlement of barnacle (Semibalanus balanoides) cyprids. Biofouling 12: 57–69.Google Scholar
- Lewis, C. A., 1978. A review of substratum selection in free-living and symbiotic Cirripeds. In Chia, F.-S. & M. E. Rice (eds.) Settlement and Metamorphosis of Marine Invertebrate Larvae. Elsevier, New York: 207–218.Google Scholar
- Manly, B. F. J., 1993. Comments on design and analysis of multiple-choice feeding preference experiments. Oecologia 93: 149–152.Google Scholar
- McClintock, J. B., B. J. Baker, C. D. Amsler & T. L. Barlow, 2000. Chemotactic tube-foot responses of the spongivorous sea star Perknaster fuscus to organic extracts of sponges from McMurdo Sound, Antarctica. Antarctic Science 12: 41–46.Google Scholar
- Roa, R., 1992. Design and analysis of multiple-choice feeding preference experiments. Oecologia 89: 509–515.Google Scholar
- Valentincic, T., 1983. Innate and learned responses to external stimuli in Asteroids. In Jangoux, M. & J. M. Lawrence (eds.), Echinoderm Studies, vol. 1. Balkema, Rotterdam: 111–138.Google Scholar