Preferences, selection and damage to seedlings under changing availability by two marsupial herbivores

McArthur, Clare; Goodwin, A. N.; Turner, Steven C.

doi:10.1016/s0378-1127(99)00342-4

Cited by 48 publications

(45 citation statements)

References 29 publications

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“…Pademelons were part of a captive colony maintained in an animal enclosure at the School of Zoology, University of Tasmania, Hobart, Tasmania, Australia, while possums were wild caught. All animals were housed and maintained following McArthur et al (2000).…”

Section: Feeding Trials Comparing Intakesmentioning

confidence: 99%

“…Leaf intake was estimated as the product of the initial leaf DM and the mid-point range of the proportion of leaf biomass removed, converted from the browse score (as done by McArthur et al 2000). Estimates of DM intake for each leaf age class was expressed as the amount of DM eaten per kilogram of body mass for each animal (gDM kg -1 BM).…”

Section: Feeding Trials Comparing Intakesmentioning

confidence: 99%

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How do soil nutrients affect within-plant patterns of herbivory in seedlings of Eucalyptus nitens?

et al. 2006

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This study assessed how the palatability of leaves of different age classes (young, intermediate and older) of Eucalyptus nitens seedlings varied with plant nutrient status, based on captive feeding trials with two mammalian herbivores, Red-bellied Pademelons (Thylogale billardierii), and Common Brushtail Possums (Trichosurus vulpecula). Seedlings were grown under three nutrient treatments (low, medium and high) and we determined how palatability was related to chemical and physical characteristics of the leaves. Pademelons ate more older leaves than young and intermediate leaves for all treatments. This pattern was best explained by sideroxylonals (formylated pholoroglucinol compounds known to deter herbivory by other marsupials), and/or essential oil compounds that were in lower concentrations in older leaves. In the low nutrient treatment, possums also ate more of the older leaves. However, in the medium and high nutrient treatments, possums ate more intermediate leaves than older leaves and showed a behavioural preference for young leaves (consuming younger leaves first) over intermediate and older leaves, in spite of high levels of sideroxylonals and essential oils. The young leaves did, however, have the highest nitrogen concentration of the leaf age classes. Thus, either sideroxylonals and essential oils provided little or no deterrent to possums, or the deterrent was outweighed by other factors such as high nitrogen. This study indicates that mammalian herbivores show different levels of relative use and damage to leaf age classes at varying levels of plant nutrient status and, therefore, their impact on plant fitness may vary with environment.

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Section: Feeding Trials Comparing Intakesmentioning

confidence: 99%

Section: Feeding Trials Comparing Intakesmentioning

confidence: 99%

How do soil nutrients affect within-plant patterns of herbivory in seedlings of Eucalyptus nitens?

et al. 2006

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“…All animals were caught, housed and maintained, following McArthur et al (2000). During the feeding trial, animals were offered a basal diet (see McArthur et al 2000) for a restricted interval of approximately 4 h in the morning following an experimental night.…”

Section: The Feeding Trialmentioning

confidence: 99%

“…During the feeding trial, animals were offered a basal diet (see McArthur et al 2000) for a restricted interval of approximately 4 h in the morning following an experimental night. This ensured that animals maintained body mass throughout the trial, while allowing us to provide only the eucalypt foliage for their normal nocturnal feeding period.…”

Section: The Feeding Trialmentioning

confidence: 99%

“…The genus has a diverse range of invertebrate and mammalian herbivore species that consume the foliage Woinarski et al 1997). Variability in the extent to which invertebrate and mammalian herbivores consume Eucalyptus foliage occurs at both the inter-and intraspecific levels (Floyd et al 1994;Lawler et al 1998;McArthur et al 2000). However, the role that plant genotype plays in this variation is poorly understood, and has never before been documented at the intra-specific level within eucalypt/mammalian herbivore systems.…”

Section: Introductionmentioning

confidence: 99%

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Genetic variation in resistance of Eucalyptus globulus to marsupial browsers

2002

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The evolution of plant defensive traits in response to selection pressures imposed by herbivores is central to co-evolutionary theory. To demonstrate the role of herbivores as selective agents on plant resistance there must be variability in plant resistance to herbivores within a plant population. This variability must be under genetic control, and the variability in plant resistant traits and consequently herbivore damage to plants must reflect variability in plant fitness. We used a common eucalypt species, Eucalyptus globulus, and two major mammalian herbivores, the common brushtail possum (Trichosurus vulpecula) and the red-bellied pademelon (Thylogale billardierii), as a system to investigate intraspecific variation in plant resistance to mammalian herbivores and to investigate if this variation has a genetic basis. We measured mammalian browsing damage on 2,302 individual trees of E. globulus, from 563 families derived from range-wide native stand seed collections of known pedigree and grown in a common environment field trial. Using a selection of trees from the field trial we then conducted a feeding trial with captive herbivores to assess if the genetic variation in plant resistance in the field was reflected in feeding preferences of captive animals, as measured by relative intake. Results from the field trial showed significant genetic variation in plant resistance amongst races, localities and amongst different families. These results were consolidated in the captive trial with similar trends in genetic variation among E. globulus localities. Dry matter intake of foliage by Trichosurus vulpecula was consistently greater than that by Thylogale billardierii; however, the intraspecific preferences of the two herbivores were significantly correlated.

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Effects of nutrient variability on the genetic-based resistance of Eucalyptus globulus to a mammalian herbivore and on plant defensive chemistry

et al. 2004

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Plant resistance to herbivores can be influenced not only by the independent effects of plant genotype and environmental variation, but by interactions between the two. The main aim of this study was to assess the effects of environmental variability (nutrient treatment) on the known genetic-based expression of resistance and defensive chemistry of Eucalyptus globulus to browsing by the generalist mammalian herbivore Trichosurus vulpecula. In a captive feeding trial, we measured intake of seedlings from one relatively resistant (Blue Gum Hill) and one relatively susceptible (St Helens) population of E. globulus grown under two nutrient treatments (no fertiliser, plus fertiliser). There was a significant genotypexfertiliser interaction effect on intake of E. globulus foliage by T. vulpecula, and the predicted genetic-based resistance of the two populations was expressed only for the non-fertilised treatment. Expression of resistance largely reflected the combined and inverse effects of nitrogen and condensed tannin concentrations. The expression of plant secondary metabolite concentration differed between compounds, but in all cases the effects of plant genotype and fertiliser treatment were independent. The formylated phloroglucinol compounds differed significantly between genotypes but not between fertiliser treatments. In contrast, the effect of plant genotype on the expression of condensed tannins was weak but they were significantly reduced by fertiliser. Essential oils were influenced by both plant genotype and fertiliser treatment and were significantly higher in the fertilised seedlings than in the non-fertilised seedlings. This study highlights interactive effects of plant genotype and environment in influencing the phenotypic expression of resistance in a eucalypt species to a mammalian browser. It also demonstrates that this interactive effect is the net result of independent effects of genotype and environment on plant chemistry and finally, that different groups of compounds within a plant can respond very differently to variation in environmental conditions.

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Preferences, selection and damage to seedlings under changing availability by two marsupial herbivores

Cited by 48 publications

References 29 publications

How do soil nutrients affect within-plant patterns of herbivory in seedlings of Eucalyptus nitens?

How do soil nutrients affect within-plant patterns of herbivory in seedlings of Eucalyptus nitens?

Genetic variation in resistance of Eucalyptus globulus to marsupial browsers

Effects of nutrient variability on the genetic-based resistance of Eucalyptus globulus to a mammalian herbivore and on plant defensive chemistry

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