Asymmetric competition via induced resistance: Specialist herbivores indirectly suppress generalist preference and populations

被引:52
作者
Long, Jeremy D. [1 ]
Hamilton, Rebecca S. [1 ]
Mitchell, Jocelyn L. [1 ]
机构
[1] Northeastern Univ, Ctr Marine Sci, Nahant, MA 01908 USA
关键词
competition; consumer prey interaction; inducible defense; macroalgae; plant-herbivore interaction; rocky intertidal; snails (Littorina spp.); trait-mediated indirect interactions;
D O I
10.1890/06-1585
中图分类号
Q14 [生态学(生物生态学)];
学科分类号
071012 ; 0713 ;
摘要
Species may compete indirectly by altering the traits of a shared resource. For example, herbivore-induced responses in plants may make plants more resistant or susceptible to additional herbivorous insect species. Herbivore-induced plant responses can significantly affect interspecific competition and herbivore population dynamics. These herbivore-herbivore indirect interactions have been overlooked in aquatic ecosystems where previous studies used the same herbivore species to induce changes and to assess the effects of these changes. We asked whether seaweed grazing by one of two herbivorous, congeneric snail species (Littorina obtusata or Littorina littorea) with different feeding strategies and preferences would affect subsequent feeding preferences of three herbivore species (both snails and the isopod Idotea baltica) and population densities of three herbivore species (both snails and a third periwinkle snail, Lacuna vincta). In addition, we measured phlorotannin concentrations to test the hypothesis that these metabolites function as induced defenses in the Phaeophyceae. Snail herbivory induced cue-specific responses in apical tissues of the seaweed Fucus vesiculosus that affected the three herbivore species similarly. When compared to ungrazed controls, direct grazing by Littorina obtusata reduced seaweed palatability by at least 52% for both snail species and the isopod species. In contrast, direct grazing by L. littorea did not decrease seaweed palatability for any herbivore, indicating herbivore-specific responses. Previous grazing by L. obtusata reduced populations of L. littorea on outplanted seaweeds by 46% but had no effect on L. obtusata populations. Phlorotannins, a potential class of inducible chemicals in brown algae, were not more concentrated in grazed seaweed tissues, suggesting that some other trait was responsible for the induced resistance. Our results indicate that marine herbivores may compete via inducible responses in shared seaweeds. These plant-mediated interactions were asymmetric with a specialist (L. obtusata) competitively superior to a generalist (L. littorea).
引用
收藏
页码:1232 / 1240
页数:9
相关论文
共 41 条
[1]  
Barbosa P, 1987, INSECT OUTBREAKS
[3]   Induction of seaweed chemical defenses by amphipod grazing [J].
Cronin, G ;
Hay, ME .
ECOLOGY, 1996, 77 (08) :2287-2301
[4]   Galactolipids rather than phlorotannins as herbivore deterrents in the brown seaweed Fucus vesiculosus [J].
Deal, MS ;
Hay, ME ;
Wilson, D ;
Fenical, W .
OECOLOGIA, 2003, 136 (01) :107-114
[5]  
Denno RF, 2000, ECOLOGY, V81, P1814, DOI 10.1890/0012-9658(2000)081[1814:FICIPQ]2.0.CO
[6]  
2
[7]   INTERSPECIFIC INTERACTIONS IN PHYTOPHAGOUS INSECTS - COMPETITION REEXAMINED AND RESURRECTED [J].
DENNO, RF ;
MCCLURE, MS ;
OTT, JR .
ANNUAL REVIEW OF ENTOMOLOGY, 1995, 40 :297-331
[8]  
Denno Robert F., 2007, P19, DOI 10.1017/CBO9780511542701.003
[9]   SEAWEED ADAPTATIONS TO HERBIVORY - CHEMICAL, STRUCTURAL, AND MORPHOLOGICAL DEFENSES ARE OFTEN ADJUSTED TO SPATIAL OR TEMPORAL PATTERNS OF ATTACK [J].
DUFFY, JE ;
HAY, ME .
BIOSCIENCE, 1990, 40 (05) :368-375
[10]   INDIRECT INTERACTIONS BETWEEN TEMPORALLY SEPARATED HERBIVORES MEDIATED BY THE HOST PLANT [J].
FAETH, SH .
ECOLOGY, 1986, 67 (02) :479-494