Induction of defences and within-plant variation on palatability in two brown algae from the northern-central coast of Chile: effects of mesograzers and UV radiation.

Macaya, Erasmo C., Rothäusler, Eva, Thiel, Martin, Molis, Markus and Wahl, Martin (2005) Induction of defences and within-plant variation on palatability in two brown algae from the northern-central coast of Chile: effects of mesograzers and UV radiation. Journal of Experimental Marine Biology and Ecology, 325 . pp. 214-227. DOI 10.1016/j.jembe.2005.05.004.

[img] Text
340_Macaya_2005_InductionOfDefencesAndWithinplant_Artzeit_pubid10464.pdf - Published Version
Restricted to Registered users only

Download (185Kb) | Contact

Supplementary data:

Abstract

Macroalgae possess different defense mechanisms in response to herbivory. Some species produce anti-herbivore secondary metabolites, but production of these substances can be costly. Therefore, algae may produce defensive metabolites only in response to herbivory (inducible defense) or defend particular parts of the alga differentially (within-alga variation). In the present study, we examined whether two species of brown algae from the SE-Pacific show evidence of inducible chemical defense (non-polar compounds) or within-alga variation of defense, which we estimated in form of palatability of differently treated algae to amphipod grazers (with live algae and agar-based food containing non-polar algal extracts). In Glossophora kunthii (C. Agardh) J. Agardh, we observed an increase in palatability after algae were acclimated for 12 days without grazers. Subsequent addition of grazers for 12 days then resulted in a reduction of palatability indicating the existence of inducible defense. After removal of grazers for 12 days, these induced effects again disappeared. The reaction of G. kunthii was triggered even by the mere presence of grazers, which suggests that this alga can respond to waterborne cues by reducing palatability. Effects were only found for agar-based food containing non-polar extracts, but not for live algae, suggesting that some parts of the algae are undefended. Our second experiment on within-alga variation confirmed that only apical (growth region) and basal parts (near the holdfast region) of G. kunthii are defended against herbivores. For the second species, Macrocystis integrifolia Bory, the first experiment revealed no induction of defense, while the second experiment on within-alga variation showed that amphipods avoided basal parts and in particular stipes of M. integrifolia but only in live algae. Although both studied algal species differed substantially in their defensive strategies, their reaction was independent of the presence or absence of UV radiation. Thus, it appears that UV effects play only a minor role in anti-herbivore defense, which is in accordance with most previous studies.

Document Type: Article
Keywords: Benthic Ecology; Chile, defenses, herbivory, induction, macroalgae, UV radiation
Research affiliation: OceanRep > GEOMAR > FB3 Marine Ecology > FB3-EOE-B Experimental Ecology - Benthic Ecology
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1016/j.jembe.2005.05.004
ISSN: 0022-0981
Projects: GAME
Date Deposited: 03 Dec 2008 16:52
Last Modified: 29 Jun 2018 11:56
URI: http://oceanrep.geomar.de/id/eprint/4716

Actions (login required)

View Item View Item

Document Downloads

More statistics for this item...