Species-specific defense strategies of vegetative versus reproductive blades of the Pacific kelps Lessonia nigrescens and Macrocystis integrifolia
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Chemical defense is assumed to be costly and therefore algae should allocate defense investments in a way to reduce costs and optimize their overall fitness. Thus, lifetime expectation of particular tissues and their contribution to the fitness of the alga may affect defense allocation. Two brown algae common to the SE Pacific coasts, Lessonia nigrescens Bory and Macrocystis integrifolia Bory, feature important ontogenetic differences in the development of reproductive structures; in L. nigrescens blade tissues pass from a vegetative stage to a reproductive stage, while in M. integrifolia reproductive and vegetative functions are spatially separated on different blades. We hypothesized that vegetative blades of L. nigrescens with important future functions are more (or equally) defended than reproductive blades, whereas in M. integrifolia defense should be mainly allocated to reproductive blades (sporophylls), which are considered to make a higher contribution to fitness. Herein, within-plant variation in susceptibility of reproductive and vegetative tissues to herbivory and in allocation of phlorotannins (phenolics) and N-compounds was compared. The results show that phlorotannin and N-concentrations were higher in reproductive blade tissues for both investigated algae. However, preferences by amphipod grazers (Parhyalella penai) for either tissue type differed between the two algal species. Fresh reproductive tissue of L. nigrescens was more consumed than vegetative tissue, while the reverse was found in M. integrifolia, thus confirming the original hypothesis. This suggests that future fitness function might indeed be a useful predictor of anti-herbivore defense in large, perennial kelps. Results from feeding assays with artificial pellets that were made with air-dried material and extract-treated Ulva powder indicated that defenses in live algae are probably not based on chemicals that can be extracted or remain intact after air-drying and grinding up algal tissues. Instead, anti-herbivore defense against amphipod mesograzers seems to depend on structural traits of living algae.
KeywordsVegetative Tissue Reproductive Tissue Feeding Assay Algal Tissue Kelp Species
We are thankful to the leaders of the GAME project Mark Lenz and Martin Wahl. Fadia Tala made many helpful suggestions on a first draft of the manuscript. We would also like to thank Prof. Dr. Ulf Karsten and coworkers for the use of the laboratory at the University of Rostock, Germany. This project was financed by the Mercator Stiftung GmbH, and FONDECYT grants 1060127 (MT, IG) and 1060503 (IG).
- Edding M, Fonck E, Macchiavello J (1994) Lessonia. In: Akatsuka I (ed) Biology of economic algae. Academic Publishing, The Hague Netherlands, pp 407–446Google Scholar
- Edgar GJ (ed) (2000) Australian marine life: the plants and animals of temperate waters. Reed New Holland, SydneyGoogle Scholar
- Harper MK, Bubni TS, Copp BR, James RD, Lindsay BS, Richardson AD et al (2001) Introduction to the chemical ecology of marine natural products. In: McClintock JB, Baker BJ (eds) Marine chemical ecology. CRC Press, Boca Raton, pp 3–69Google Scholar
- Hoffmann A, Santelices B (eds) (1997) Flora marina de Chile central: marine flora at central Chile. Universidad Católica de Chile, SantiagoGoogle Scholar
- Macaya EC, Rothäusler E, Thiel M, Molis M, Wahl M (2005) Induction of defenses and within-alga variation of palatability in two brown algae from the northern-central coast of Chile: effects of mesograzers and UV radiation. J Exp Mar Biol Ecol 325:214–227. doi: 10.1016/j.jembe.2005.05.004 CrossRefGoogle Scholar
- Maschek JA, Baker BJ (2008) The chemistry of algal secondary metabolism. In: Amsler CD (ed) Algal chemical ecology. Springer, Heidelberg, pp 1–24Google Scholar
- Pérez-Schultheiss J, Crespo JE (2008) A new species of Parhyalella Kunkel, 1910 (Amphipoda, Talitroidea, Dogielinotidae) from the coast of Chile. Zootaxa 1724:61–68Google Scholar
- Winter FC, Estes JA (1992) Experimental evidence for the effects of polyphenolic compounds from Dictyoneurum californicum (Phaeophyta; Laminariales) on feeding rate and growth in the red abalone (Haliotus rufescens). J Exp Mar Biol Ecol 155:263–277. doi: 10.1016/0022-0981(92) 90067-K CrossRefGoogle Scholar