Dataset: Palatability of Galaxaura extract on Padina to herbivores from in the Viti Levu, Fiji from 2011 (Killer Seaweeds project)

To test the hypothesis that an increase in the palatability of Galaxaura following competition was owing to changes in antiherbivore defensive chemistry, we tested the deterrent effects of hydrophobic extracts from treatment versus control Galaxaura against herbivorous fishes in the field. These extracts were the same as those used to assess induction of allelopathy in Galaxaura. To test extract deterrence against herbivorous surgeonfish (Naso lituratus and Naso unicornis), we re-suspended each extract in ether, coated each at a natural volumetric concentration on five blades (a 2.04+0.03 ml volumetric equivalent, mean+ s.e.; n = 10) of blotted dry and pre-weighed Padina boryana (a preferred prey of N. lituratus and N. unicornis [30], hereafter ‘Padina’), allowed the ether to evaporate, inserted each set of blades 5 cm apart on their own 60 cm section of 3-stranded rope (n = 12 ropes extract-1), and deployed pairs of treatment and control ropes in the field (as described earlier).

Because feeding on Padina was rapid (approx. 10 min pair-1), we deployed one pair at a time, monitored feeding and recollected pairs when approximately 50% of the total biomass within each pair was consumed. We observed only N. lituratus and N. unicornis feeding on the Padina. Following assays, seaweeds were bagged in situ and returned to the laboratory, where they were blotted dry and re-weighed. Given the duration of each assay and our visual assessment that seaweed tissues were not being lost to processes other than herbivory, we did not deploy caged controls.

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.