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Invertebrate Herbivory (invertebrate + herbivory)

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Life Sciences100%

Selected Abstracts

Seedling Mortality and Herbivory Damage in Subtropical and Temperate Populations: Testing the Hypothesis of Higher Herbivore Pressure Toward the Tropics

BIOTROPICA, Issue 2 2010
Ek Del-Val
ABSTRACT Herbivory rates are generally thought to be higher in tropical than in temperate forests. Nevertheless, tests of this biogeographic prediction by comparing a single plant species across a tropical-temperate range are scarce. Here, we compare herbivore damage between subtropical and temperate populations of the evergreen tree Aextoxicon punctatum (Olivillo), distributed between 30° and 43° S along the Pacific margin of Chile. To assess the impact of herbivory on Olivillo seedlings, we set up 29 experimental plots, 1.5 × 3 m: 16 in forests of Fray Jorge National Park (subtropical latitude), and 13 in Guabún, Chiloé Island (temperate latitude). Half of each plot was fenced around with chicken wire, to exclude small mammals, and the other half was left unfenced. In each half of the plots we planted 16 seedlings of Olivillo in December 2003, with a total of 928 plants. Seedling survival, leaf production and herbivory by invertebrates were monitored over the next 16 mo. Small mammal herbivores killed ca 30 percent of seedlings in both sites. Nevertheless, invertebrate herbivory was greater in the temperate forest, thus contradicting the expected trend of increasing herbivore impact toward the tropics. Seedling growth was greater in subtropical forest suggesting better conditions for tree growth or that higher invertebrate herbivory depressed seedling growth in the temperate forest. Invertebrate herbivory increased toward temperate latitudes while small mammal herbivory was similar in both sites. We suggest that comparison of single species can be useful to test generalizations about latitudinal patterns and allow disentangling factors controlling herbivory patterns across communities. Abstract in Spanish is available at http://www.blackwell-synergy.com/loi/btp [source]

Selenium accumulation protects Brassica juncea from invertebrate herbivory and fungal infection

NEW PHYTOLOGIST, Issue 2 2003
Brady Hanson
Summary ,,Certain plant species hyperaccumulate selenium (Se) up to 0.6% of their dry weight. It is not known whether Se hyperaccumulation offers the plants any advantage. In this study the hypothesis was tested that Se can protect plants from invertebrate herbivory or fungal infection. ,,Indian mustard (Brassica juncea) plants grown with or without Se were subjected to herbivory by caterpillars (Pieris rapae) and snails (Mesodon ferrissi), or to fungal infection by a root/stem pathogen (Fusarium sp.) and a leaf pathogen (Alternaria brassicicola). ,,When given a choice between leaves with or without Se (0.1% Se of leaf d. wt), the caterpillars strongly preferred leaves without Se (P < 0.01), while the snails preferred leaves containing Se (P < 0.015). When consumed, the Se leaves were lethal to the caterpillars. The snails showed no toxicity symptoms, even though their tissue Se concentrations were comparable with the caterpillars. Se-containing plants were less susceptible to infection by both fungi. ,,In conclusion, Se was shown to protect Indian mustard plants from fungal infection and from herbivory by caterpillars, but not by snails. [source]

Seedling Mortality and Herbivory Damage in Subtropical and Temperate Populations: Testing the Hypothesis of Higher Herbivore Pressure Toward the Tropics

BIOTROPICA, Issue 2 2010
Ek Del-Val
ABSTRACT Herbivory rates are generally thought to be higher in tropical than in temperate forests. Nevertheless, tests of this biogeographic prediction by comparing a single plant species across a tropical-temperate range are scarce. Here, we compare herbivore damage between subtropical and temperate populations of the evergreen tree Aextoxicon punctatum (Olivillo), distributed between 30° and 43° S along the Pacific margin of Chile. To assess the impact of herbivory on Olivillo seedlings, we set up 29 experimental plots, 1.5 × 3 m: 16 in forests of Fray Jorge National Park (subtropical latitude), and 13 in Guabún, Chiloé Island (temperate latitude). Half of each plot was fenced around with chicken wire, to exclude small mammals, and the other half was left unfenced. In each half of the plots we planted 16 seedlings of Olivillo in December 2003, with a total of 928 plants. Seedling survival, leaf production and herbivory by invertebrates were monitored over the next 16 mo. Small mammal herbivores killed ca 30 percent of seedlings in both sites. Nevertheless, invertebrate herbivory was greater in the temperate forest, thus contradicting the expected trend of increasing herbivore impact toward the tropics. Seedling growth was greater in subtropical forest suggesting better conditions for tree growth or that higher invertebrate herbivory depressed seedling growth in the temperate forest. Invertebrate herbivory increased toward temperate latitudes while small mammal herbivory was similar in both sites. We suggest that comparison of single species can be useful to test generalizations about latitudinal patterns and allow disentangling factors controlling herbivory patterns across communities. Abstract in Spanish is available at http://www.blackwell-synergy.com/loi/btp [source]