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Constraints on the utilisation of the invasive Chinese tallow tree Sapium sebiferum by generalist native herbivores in coastal prairies
1. Introduced plants generally have lower generalist herbivore loads than native plants. Herbivores may be avoiding a potentially edible food source (Behavioural Constraint Hypothesis) or defences of introduced plants may be unusually toxic (Novel Defence Hypothesis). 2. To examine these hypotheses,...
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Published in: | Ecological entomology 2004-02, Vol.29 (1), p.66-75 |
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Main Authors: | , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | 1. Introduced plants generally have lower generalist herbivore loads than native plants. Herbivores may be avoiding a potentially edible food source (Behavioural Constraint Hypothesis) or defences of introduced plants may be unusually toxic (Novel Defence Hypothesis).
2. To examine these hypotheses, acridid grasshoppers (
Melanoplus angustipennis
and
Orphullela pelidna
) were enclosed in a Texas grassland. Each enclosure contained native prairie vegetation and a seedling of either introduced
Sapium sebiferum
(Chinese tallow tree) or native
Celtis laevigata
(hackberry).
Sapium
invades many ecosystems in the south‐east U.S.A.
Celtis
seedlings also establish in these ecosystems.
3. Although grasshoppers usually feed sparingly on
Sapium
, in field enclosures they fed heavily on this introduced tree species, supporting a role for behavioural avoidance. In laboratory feeding trials,
M. angustipennis
grasshoppers preferred
Sapium
foliage over the foliage of three native tree species. In a greenhouse experiment,
M. angustipennis
individuals fed more on
Sapium
in prairie mesocosms if they were conditioned on
Sapium
.
4. In another field experiment with single seedlings in enclosures, grasshoppers consumed similar amounts of
Sapium
from its introduced (Texas, U.S.A.) and native (China) ranges, suggesting that
Sapium
may have been a suitable host plant since it was introduced. Behavioural avoidance by generalist herbivores may contribute to
Sapium
's low herbivore load in its introduced range. |
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ISSN: | 0307-6946 1365-2311 |
DOI: | 10.1111/j.0307-6946.2004.00575.x |