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dc.contributor.authorHay, Mark E.en_US
dc.contributor.authorKappel, Quaker E.en_US
dc.contributor.authorFenical, Williamen_US
dc.date.accessioned2012-01-18T17:00:12Z
dc.date.available2012-01-18T17:00:12Z
dc.date.issued1994
dc.identifier.citationHay, M. E., Q. E. Kappel, and W. Fenical. 1994. Synergisms in plant defenses against herbivores: interactions of chemistry, calcification, and plant quality. Ecology 75: 1714-1726.en_US
dc.identifier.issn0012-9658
dc.identifier.urihttp://hdl.handle.net/1853/42186
dc.description© Ecological Society of Americaen_US
dc.description.abstractMany tropical seaweeds and benthic invertebrates produce both secondary metabolites and calcium carbonate (CaC03) particles or spicules that serve as possible defenses against consumers. To evaluate the relative defensive value ofCaC03 , secondary metabolites, and the potential synergistic or additive effects of the two, we made artificial agar-based "seaweeds" in which we manipulated algal organic content, CaC03 , and the secondary metabolites produced by the calcified green seaweeds Rhipocephalus phoenix, Udotea cyathiformis, and Halimeda goreauii, all of which are relatively resistant to herbivores. The effects ofthese manipulations on herbivore feeding were evaluated using three different types of herbivores, the sea urchin Diadema antillarum, the amphipod Cymadusa filosa, and a mixed-species group of small parrotfishes. Addition of finely powdered CaC03 as 69% of food dry mass had no effect on feeding by parrotfishes, deterred feeding by Cymadusa, and deterred Diadema when food organic content was low but not when it was higher. Although calcification of algal tissues has generally been considered a structural defense that hardens seaweed thalli and makes them more resistant to attack, the decreased feeding on CaC03-containing foods in our assays occurred without any measurable alteration of food toughness. At natural concentrations, semi purified secondary metabolites from Rhipocephalus or Udotea deterred feeding by all three herbivores. In most assays, feeding was depressed more by the addition of metabolites from Rhipocephalus or Udotea than by the addition of CaC03 even though CaC03 was added at 1.3-2,2 times the natural concentration for these plants. In contrast, the major metabolite from Halimeda goreauii, when tested alone, did not affect feeding by any of the herbivores. In two of our nine assays, the synchronous combination ofCaC03 and secondary metabolites acted synergistically and deterred feeding significantly more than the sum of the effects of each tested separately. Mechanisms producing these synergisms are unknown, but it is possible that calcification could also be acting as a chemical defense by altering gut pH in ways that increase the potency of the secondary metabolites. It is common for chemical, structural, morphological, and nutritional deterrents to co-occur in individual prey species. For some plant-herbivore interactions, the combined effects of these characteristics can be much more than the sum of their separate effects.en_US
dc.language.isoen_USen_US
dc.publisherGeorgia Institute of Technologyen_US
dc.subjectCalcificationen_US
dc.subjectChemical defenseen_US
dc.subjectComplex interactionsen_US
dc.subjectMarineen_US
dc.subjectPlant-herbivore interactionsen_US
dc.subjectSeaweedsen_US
dc.titleSynergisms in plant defenses against herbivores: interactions of chemistry, calcification, and plant qualityen_US
dc.typeArticleen_US
dc.contributor.corporatenameUniversity of North Carolina at Chapel Hill. Institute of Marine Sciencesen_US
dc.contributor.corporatenameScripps Institution of Oceanographyen_US
dc.contributor.corporatenameUniversity of California (System). Institute of Marine Resourcesen_US
dc.publisher.originalEcological Society of Americaen_US


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