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The plant vigor hypothesis applies to a ..

Testing Hypotheses about Herbivore Responses to Plant Vigor and Herbivore ..

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Galls on smaller leaves do not refute the Plant Vigour Hypothesis

Price's hypothesis says that any animal that feeds preferentially on new growth – a flush‐feeder – will do better if the plant is growing vigorously.

we tested the Plant Vigor Hypothesis in a neotropical system comprised of the beetle ..

Three hypotheses predict how insect herbivores perform on stressed host plants. The plant stress hypothesis (PSH) predicts improved insect performance on stressed hosts. The plant vigour hypothesis (PVH) predicts that insects closely associated with their host, such as gall-formers, will perform better on vigorously growing non-stressed hosts. The third hypothesis, the Insect Performance Hypothesis (IPH) predicts that wood-feeders, sap-feeders and miners will perform better on stressed hosts, while leaf-feeders and gall-formers will perform better on non-stressed hosts. These hypotheses were devel-oped, however, without separating different types of plant stress. In this review we tested these hypoth-eses across five insect feeding-guilds and twelve host-plant stress types, from more than 200 published studies on insect performance. When all host-plant stress types were pooled, the results suggested wood, sap and leaf-feeders performed better on stressed host plants, while miners and gall-formers performed better on non-stressed host plants, thus supporting the PVH. However, when all insect feeding-guilds were pooled, it was found that host-plant-stress type also influenced insect performance, which was generally higher when host plants were growing under reduced moisture, light or CO 2, increased soil nitrogen or on younger plants. When host-plant-stress type and insect feeding-guild were separated, it was found that insect performance across feeding guilds varied with the type of host-plant stress encountered suggesting that insects in different feeding guilds may respond to different physio-logical and morphological changes in the plant. This review highlights the fact that insect performance is often significantly affected by host-plant stress, but that the direction of the response is variable. Although this review did not fully support any of the three theoretical hypotheses tested, there were consistent relationships between some insect-feeding guilds and host-plant-stress types that would allow the prediction on whether a specific biological control agent might perform better under a specific host-plant stress.

plant vigour and pulsed stress hypotheses ..

Reply to Galls on smaller leaves do not refute the Plant Vigour Hypothesis.

; ; ; . 2012 Aphids in a changing world: testing the plant stress, plant vigour and pulsed stress hypotheses. Agricultural and Forest Entomology, 14 (2). 177-185.

; ; ; . 2012 Aphids in a changing world: testing the plant stress, plant vigour and pulsed stress hypotheses. Agricultural and Forest Entomology, 14 (2). 177-185.

Price P W 1991 The plant vigour hypothesis and …

Thus, the plant vigour hypothesis was ..

2. The plant stress and plant vigour hypotheses have been suggested as opposing ways in which foliage quality influences herbivore abundance. In many plants, however, vigorous growing foliage co-exists with stressed or damaged foliage.

1. The plant stress, plant vigour and pulsed stress hypotheses describe the relationships between drought stress, plant quality and herbivore performance. We used an aphid- Brassica system to test these hypotheses under different drought treatments.2. The quantity of water added per plant/week was 75%, 50% and 25% of the control (unstressed) water regime for low, medium and high drought stress, respectively, and 50% applied fortnightly for pulsed drought stress. The performance of a ‘senescence’ (generalist) and a ‘flush’ feeder (specialist) aphid species and host plant quality were assessed.3. Drought treatments had a similar effect on the fecundity and intrinsic rate of increase of both aphid species. Aphid perforance on unstressed and highly drought-stressed plants was significantly lower compared with medium drought stress. On average, 20% greater fecundity and 40% greater intrinsic rates of increase were recorded for both aphid species at medium drought stress compared with unstressed plants.4. Plant biomass and relative water contents were significantly greater for unstressed plants compared with high and pulsed drought treatments. Foliar nitrogen concentration was significantly greater in the high drought stress and pulsed treatments, and the dominant glucosinolate (glucobrassicin) concentration was significantly greater in drought stress treatments.5. The present study supports the plant stress hypothesis, although the plant vigour and pulsed stress hypotheses are not supported by our data. The implications of these findings for plant–herbivore interactions under changing environmental conditions are discussed.

the plant vigour hypothesis, ..
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  • One hypothesis, the Plant Stress ..

    (1991) Plant Vigour Hypothesis

  • 10/09/2009 · Brazilian Journal of Biology ..

    The plant vigour hypothesis revisited – how is browsing by ungulates and elephant related to woody species growth rate?

  • 14/01/2018 · LETTER TO THE EDITOR

    Price P W 1991 The plant vigour hypothesis and herbivore attack Oikos 62244 251 from BIOCHEM 23772 at Rutgers

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