To test extract deterrence against other herbivores, we resuspended the same Galaxaura extracts in ether, coated each at a natural volumetric concentration on three branches (a 0.74+ 0.02 ml volumetric equivalent) of blotted dry and pre-weighed Amphiroa crassa (a heavily calcified seaweed avoided by Naso spp. but consumed by the parrotfish Chlorurus sordidus [30], hereafter ‘Amphiroa’), allowed the ether to evaporate, inserted each set of branches 5 cm apart on their own 60 cm section of 3-stranded rope (n = 12 ropes extract-1), and deployed paired treatment and control ropes in the field (as described earlier). We also coated Amphiroa only with ether and deployed them as caged controls within 1 m of each pair to control for changes in seaweed mass unrelated to herbivory. Grazing on Amphiroa was low (only five pairs received detectable grazing) and assays lasted 3-5 days. We calculated the mass of Amphiroa consumed among the five pairs with detectable grazing using the formula described earlier.
Relevant References:
* Rasher DB and ME Hay. "Competition induces allelopathy but suppresses growth and anti-herbivore defense in a chemically rich seaweed". Proceedings of the Royal Society: B-Biological Sciences. vol. 281 no. 1777 20132615, 2014 (http://dx.doi.org/10.1098/rspb.2013.2615).
Rasher DB, Stout EP, Engel S, Kubanek J, and ME Hay. "Macroalgal terpenes function as allelopathic agents against reef corals", Proceedings of the National Academy of Sciences, v. 108, 2011, p. 17726.
Beattie AJ, ME Hay, B Magnusson, R de Nys, J Smeathers, JFV Vincent. "Ecology and bioprospecting," Austral Ecology, v.36, 2011, p. 341.
Rasher DB and ME Hay. "Seaweed allelopathy degrades the resilience and function of coral reefs," Communicative and Integrative Biology, v.3, 2010.
Hay ME, Rasher DB. "Corals in crisis," The Scientist, v.24, 2010, p. 42.
Hay ME and DB Rasher. "Coral reefs in crisis: reversing the biotic death spiral," Faculty 1000 Biology Reports 2010, v.2, 2010.
Rasher DB and ME Hay. "Chemically rich seaweeds poison corals when not controlled by herbivores", Proceedings of the National Academy of Sciences, v.107, 2010, p. 9683.