Cost of chemical defence in the red alga Delisea pulchra

Dworjanyn, Symon A., Wright, Jeffrey T., Paul, Nicholas A., de Nys, Rocky, and Steinberg, Peter D. (2006) Cost of chemical defence in the red alga Delisea pulchra. Oikos, 113 (1). pp. 13-22.

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The concept of a cost of defence is fundamental to theories for the evolution of defences against consumers. However, the evidence for a cost of plant chemical defences is mixed, and often indirect. This is particularly true for marine macroalgae (seaweeds), for which inferences of cost to date rely almost exclusively on phenotypic correlations between one class of secondary metabolites (brown algal phlorotannins) and growth (or, in one instance, fecundity). No studies of the cost of seaweed chemical defense have experimentally manipulated the presence of secondary metabolites in a controlled fashion and only one previous study has considered genetic background as a factor. Here we measured the cost of halogenated furanones to the red seaweed Delisea pulchra in three ways: a) phenotypic correlations between concentrations of furanones and fecundity in field collected thalli; b) genetic correlations between concentrations of furanones and growth for clones of thalli grown from tetraspores, and c) by comparing growth rates of thalli for which furanone production was experimentally inhibited (furanone -) vs thalli which produced furanones (furanone +). Two of our three tests-correlations between furanones and fecundity, and the growth of furanone (+) vs furanone (−) thalli-indicated a cost of furanones to D. pulchra but genetic correlations between furanones and growth did not. We suggest that these apparently conflicting results are consistent with the consequences of apical growth in this alga, and may further result from a cost of furanones only being manifested at critical developmental stages or times of tissue differentiation.

Item ID: 4079
Item Type: Article (Research - C1)
ISSN: 1600-0706
Keywords: Delisea pulchra; furanones; chemical ecology
Date Deposited: 29 Oct 2009 22:13
FoR Codes: 05 ENVIRONMENTAL SCIENCES > 0501 Ecological Applications > 050104 Landscape Ecology @ 100%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970106 Expanding Knowledge in the Biological Sciences @ 100%
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