Increased resistance towards generalist herbivory in the new range of a habitat-forming seaweed
Interactions between plants and their biotic environment can drastically change during range-expansion and result in rapid adaptive evolution of plant traits. According to the influential evolution of increased competitive ability (EICA) hypothesis escape from specialist natural enemies will lead to...
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Published in | Ecosphere (Washington, D.C) Vol. 3; no. 12; pp. art125 - 13 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
Washington
Ecological Society of America
01.12.2012
John Wiley & Sons, Inc |
Subjects | |
Online Access | Get full text |
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Summary: | Interactions between plants and their biotic environment can drastically change during range-expansion and result in rapid adaptive evolution of plant traits. According to the influential evolution of increased competitive ability (EICA) hypothesis escape from specialist natural enemies will lead to a reduction in defense levels, but the way in which generalist consumers in the new ranges affect the evolution of plant defenses remains poorly understood. We conducted a four month controlled environment experiment to examine if the high densities of the generalist herbivore
Idotea baltica
in the Baltic Sea have selected for increased grazer-resistance in
Fucus vesiculosus
, a North Atlantic seaweed that has expanded into large parts of the brackish Baltic Sea. Genetic analysis using microsatellites showed that the sampled populations are genetically distinct, which strongly suggests that traits under divergent selection may readily diverge and populations evolve local adaptations. Feeding trials and measurements of defense metabolites, i.e., phlorotannins, showed that
F. vesiculosus
from the Baltic Sea was least preferred and contained more than 50% higher constitutive levels of phlorotannins than conspecifics in the North Sea (Skagerrak), while algae from the Öresund, one of the sounds connecting the Baltic Sea to the Skagerrak, had intermediate resistance levels both in terms of grazer preference and phlorotannin levels. These results suggest that the higher grazing pressure on
F. vesiculosus
expanded into the Baltic Sea has resulted in the evolution of increased resistance towards generalist grazing. |
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Bibliography: | Corresponding Editor: D. P. C. Peters. |
ISSN: | 2150-8925 2150-8925 |
DOI: | 10.1890/ES12-00203.1 |