e-journal

The relative importance of resources and natural enemies in determining herbivore abundance: thistles, tephritids and parasitoids

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Summary
1. The relative importance of host-plant resources and natural enemies in influencing the abundance
of insect herbivores was investigated in potted plant and natural population experiments, using
tephritid (Diptera: Tephritidae) flies, their host plant, creeping thistle Cirsium arvense, and their
Hymenoptera parasitoids.
2. Experimental manipulation of host-plant quality (i.e. levels of host-plant nutrients) and resource availability (i.e. the number of buds) increased tephritid abundance. There was no evidence that the seed-feeding tephritid fly Xyphosia miliaria preferentially oviposited on fertilized C. arvense.
3. At low thistle densities, X. miliaria showed a constant rate of resource exploitation. At higher
thistle densities, a threshold was detected, above which additional buds were not attacked.
4. Parasitism attack was variable across host (tephritid) densities but levels of parasitism were
consistently higher on the fertilized thistles.
5. Experimental manipulation of host-plant quality and resource availability (quantity) not only directly affects the tephritid population but also, indirectly, leads to high rates of parasitism. Both chemical and physical characteristics of host plants affect the performance of natural enemies.
6. Both top-down and bottom-up forces act to influence tephritid abundance, with bottom-up influences appearing to be the most important.

Key-words: bottom-up, interactions, Tephritidae, top-down, tritrophic.

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Ketersediaan

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Informasi Detail

Judul Seri

Journal of Animal Ecology

No. Panggil

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Penerbit

London : British Ecological Society., 2008

Deskripsi Fisik

Journal of Animal Ecology 2008, 77 , 1063–1071

Bahasa

English

ISBN/ISSN

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Klasifikasi

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Tipe Isi

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Tipe Media

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Tipe Pembawa

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Edisi

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Subjek

BIOLOGI

Info Detail Spesifik

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Pernyataan Tanggungjawab

agus

Versi lain/terkait

Lampiran Berkas

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