Evolution Of Plant Resistance Research Articles

Efficacy and Nontarget Effects of Glyphosate and Two Organic Herbicides for Invasive Woody Vine Control

Mat-forming vines constitute half of invasive plant cover in eastern United States forests. Although glyphosate provides effective control, it has been garnering waning public acceptance due to its potential for harming human health and nontarget organisms, and due to the evolution of plant resistance. Since 67% of eastern Unites States forests are owned by private individuals, finding more acceptable chemical controls for invasive plants is important. Organic herbicides have been used for herbaceous weed control in agriculture. However, there have been no published studies of their efficacy in controlling woody plants or of their potential nontarget effects in natural areas. We compared the ability of two commercially available, organic herbicide formulations (pelargonic acid and cinnamon plus clove oils) against glyphosate to suppress growth of four woody vines, Akebia quinata, Euonymus fortunei, Hedera helix, and Vinca minor, in an urban woodland. We also tested whether these herbicides affected soil nematodes and the germination of moss and fern spores from soil. We found that glyphosate killed these vines after two spray treatments, but that a third treatment was needed the next year for the organic herbicides to kill or reduce vines. This reduction lasted into a third summer. We detected no herbicide effects on nematode densities and functional feeding groups, nor on abundance and species richness of moss and fern germinants. Although these organic herbicides cost 5–6.5 times more than glyphosate at dosages used, they greatly reduced these woody vines and can expand choices for chemical plant control for natural areas managers.

Evolutionary and environmental effects on the geographical adaptation of herbivory resistance in native and introduced Solidago altissima populations

To understand rapid evolution in plant resistance to herbivory, it is critical to determine how the genetic correlation among resistances varies genetically and/or environmentally. We conducted a reciprocal transplant experiment of tall goldenrod, Solidago altissima with multiple replicates within the native range (USA) and the introduced range (Japan) to explore the differences in phenotypic traits of resistance to multiple herbivorous insects and their relationships between and within the countries. The Japanese plants were more resistant to the lace bug, Corythucha marmorata, which had recently invaded Japan, but were more susceptible to other herbivorous insects compared to the USA plants. An antagonistic relationship was found between plant resistances to lace bugs and other herbivorous insects in both USA and Japanese plants. In addition, this relationship was more obvious in gardens with a high level of foliage damage than in gardens with a low level of foliage damage by other herbivorous insects. An antagonistic relationship between resistances to aphids and lace bugs was also observed in USA gardens, but not in Japanese garden. These results suggest that the strength of constraints on the evolution of plant resistance due to genetic trade-offs may differ among biotic environments, including community structure of herbivorous insects. Therefore, differences in herbivorous insect communities between the native and introduced ranges can result in the rapid evolution of greater resistance in plants in the introduced range than in the native range.

Evolution of plant resistance and tolerance to frost damage

AbstractPlant defence against any type of stress may involve resistance (traits that reduce damage) or tolerance (traits that reduce the negative fitness impacts of damage). These two strategies have been proposed as redundant evolutionary alternatives. A late‐season frost enabled us to estimate natural selection and genetic constraints on the evolution of frost resistance and tolerance in a wild plant species. We employed a genetic selection analysis (which is unbiased by environmental correlations between traits and fitness) on 75 paternal half‐sibling families of annual wild radish [Raphanus raphanistrum (Brassicaceae)]. In an experimental population in southern Ontario, we found strong selection favouring plant resistance to frost, but selection against tolerance to frost. The selection against tolerance may have been caused by a cost of tolerance, as we provide evidence for a negative genetic correlation between tolerance and fitness in the absence of frost damage. Although we found no evidence for the theoretically predicted trade‐off between frost tolerance and resistance among our families, we did detect negative correlational selection acting on the two traits, indicating that natural selection favoured high resistance combined with low tolerance and low resistance coupled with high tolerance, but not high or low levels of both traits together. There were few genetic correlations between the measured traits overall, but frost tolerance was negatively correlated with initial seed mass, and frost resistance was positively correlated with resistance to insect herbivory. Periodic episodes of strong selection such as that caused by the late‐season frost may be disproportionately important in evolution, and are likely becoming more common because of human alterations of the environment.

Linking plant genotype, plant defensive chemistry and mammal browsing in a Eucalyptus species

Summary In the field of plant–herbivore interactions a major focus of research is the importance of herbivores as selective agents on the evolution of plant resistance. Evidence to support the role of herbivores as selective agents must demonstrate that the intraspecific variation in plant resistance, and the variation in the plant resistive trait, are under genetic control. Predominantly, research in this field has concentrated on plant–insect systems, with much less emphasis on plant–mammal interactions. In a common Eucalyptus species, Eucalyptus globulus (Labill.), variation in resistance to a mammalian herbivore, Trichosurus vulpecula (Kerr, 1792), is under genetic control. In this paper, plants of known genetic stock grown in a common‐environment field trial were used to investigate the plant characteristic responsible for resistance of E. globulus to T. vulpecula and to determine if there was a genetic basis to variation in the defensive trait. The results demonstrate that a formylated phloroglucinol compound, sideroxylonal, is the dominant plant secondary metabolite that determined intake of E. globulus juvenile coppiced foliage by T. vulpecula, and that this metabolite is under significant genetic control. These results are discussed in the context of the possible role T. vulpecula may play as a selective agent on the evolution of resistance in E. globulus.

How good are we at predicting the field host-range of fungal pathogens used for classical biological control of weeds?

After release, a classical biocontrol agent is expected to become a permanent part of its new environment and it is vital to ensure, as far as possible, that it will do more good than harm there. This is done through risk assessment, which invariably includes host-range testing. The use of pathogenic fungi as classical biological control agents for weeds began in 1971. To date, 26 species of fungi, originating from 15 different countries, have been used as classical biocontrol agents against over 26 species of weeds in seven countries. Information is presented on the performance of these pathogens in the field after release, compared with predictions made on the basis of prerelease host-range testing. The mechanisms and evolution of plant resistance are discussed in relation to risk assessment. No reports were uncovered of deliberately introduced fungi unexpectedly attacking nontarget plants after release. Indeed, host-range testing results have often proved conservative, with a number of examples of pathogens attacking nontarget plants in prerelease tests, but not being recovered from these species in the field. It is concluded that risk assessments based on rigorous host-range testing, combined with a good understanding of the taxonomy, biology, and ecology of the agent, the target weed, and nontarget species, can ensure that the introduction of exotic pathogens is a safe and environmentally benign method of weed control.

Evolution of plant resistance at the molecular level: ecological context of species interactions.

Molecular data regarding the diversity of plant loci involved in resistance to herbivores or pathogens are becoming increasingly available. These genes demonstrate variable patterns of diversity, suggesting that they differ in their evolutionary history. In parallel, the study of natural variation for resistance, generally conducted at the phenotypic level, has shown that resistance does not evolve solely under selection pressures exerted by enemies. Metapopulation dynamics and other ecological characteristics of interacting species also appear to have a large impact on resistance evolution. Until now, studies of resistance at the molecular level have been conducted separately from ecological studies in extant populations. Future progress requires an evolutionary approach integrating both molecular and ecological aspects of resistance evolution. Such an approach will contribute greatly to our understanding of the evolution of molecular diversity at loci involved in biotic stress.

Effects of willow hybridisation and simulated browsing on the development and survival of the leaf beetle Phratora vitellinae

BackgroundInterspecific hybridisation is common between many plant species and causes rapid changes in a variety of plant characters. This may pose problems for herbivores because changes in recognition characters may be poorly correlated with changes in quality characters. Many studies have examined different systems of hybrids and herbivores in attempts to understand the role of hybridisation in the evolution of plant resistance. The results from different systems are variable. Studies of hybrids between Salix caprea (L., Salicaceae) and S. repens show that they are intermediate between the two parental species in most resistence characters. However, a plants herbivore resistence depends also on its biotic and abiotic environment. Important biotic factors that may influence plant growth and plant chemistry include the interactions between different herbivores that occur through their exploitation of common host plants. Although the effects on plants of previous herbivory are likely to be strongly affected by environmental conditions, they are also species-specific. Damage may therefore have different effects on hybrids than on their parental species, and this could influence the performance of herbivores on pure and hybrid species of plants. To evaluate the effects of hybridisation on insect performance, the development and survival rates of Phratora vitellinae (L. 1758, Coleoptera: Chrysomelidae) larvae on pure S. repens, pure S. caprea and Fl hybrids of the two species was monitored. Further, to examine the effect of herbivorous mammals on the performance of the larvae, plants were damaged to simulate winter foraging by voles or spring leaf stripping by moose.ResultsThe results show that development rates were highest on S. repens and equally low on S. caprea and the Fl hybrid. In addition, development of the plants treated to simulate mammalian herbivore damage was slower than that of corresponding controls.ConclusionsThe results of this experiment suggest that P. vitellinae has a higher development rate, and thus probably higher performance, on species with high concentrations of phenolic glucosides. Therefore, it would be of adaptive benefit for P. vitellinae females to have an ovipositional preference for S. repens, compared to S. caprea and intermediate preference for Fl hybrids. The faster development observed on S. repens supports the hypothesis that P. vitellinae obtains additional adaptive benefits from phenolic glucosides beyond protection against predators. Therefore, it is important to consider further factors, such as damage caused by other herbivores, when studying this hybrid complex.

Prior flea beetle herbivory affects oviposition preference and larval performance of a potato beetle on their shared host plant

Abstract 1. The herbaceous plant Solanum carolinense (L.) (Solanaceae) is host to a number of specialist insects, including the leaf‐feeding beetles Epitrix fuscula (Crotch) and Leptinotarsa juncta (Germar) (Coleoptera: Chrysomelidae). Potted individuals of S. carolinense were subjected to one of two treatments: exposure to herbivory by E. fuscula or exclusion of all herbivores. The effects of E. fuscula herbivory on larval performance and oviposition preference of L. juncta were investigated.2. Although the masses of the L. juncta pupae did not differ between the two treatments, larvae feeding on damaged plants developed more slowly than those feeding on undamaged plants.3. In both paired leaf choice trials and whole plant choice trials, larvae of L. juncta showed no preference for undamaged versus damaged hosts.4. In a field transplant experiment, adult L. juncta females showed slight feeding preferences and strong oviposition preferences for undamaged plants versus plants that had been fed on by E. fuscula.5. The results are discussed with reference to their implications for plant‐mediated competition among herbivores and constraints on the evolution of plant resistance.

Evolution of plant resistance and susceptibility to fungal invaders

(1987). Evolution of plant resistance and susceptibility to fungal invaders. Canadian Journal of Plant Pathology: Vol. 9, No. 4, pp. 389-397.

Evolution of Plant Resistance and Herbivore Population Cycles

Previous articleNext article No AccessLetters to the EditorsEvolution of Plant Resistance and Herbivore Population CyclesAdam ŁomnickiAdam Łomnicki Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The American Naturalist Volume 111, Number 977Jan. - Feb., 1977 Published for The American Society of Naturalists Article DOIhttps://doi.org/10.1086/283153 Views: 3Total views on this site Copyright 1977 The University of ChicagoPDF download Crossref reports no articles citing this article.

Genetic feedback and the evolution of plant resistance

The genetic feedback hypothesis suggests that plants do not passively allow herbivores to feed upon them, but rather, via natural selection, evolve resistance mechanisms. The herbivores themselves select the particular mechanism of resistance by feeding most heavily upon the most desirable, i.e. least resistant, plants. The degree to which plants are able to limit herbivore feeding depends upon the relative fitness of the plant phenotypes including resistance maintenance costs. A mutual balance is developed as a result of co-evolution between the herbivores and their host plants such that the herbivore population is regulated by the amount of energy that can be removed from the plant population without increasing the level of plant resistance. The concept of genetic feedback is not limited to herbivore—plant interactions, but may be extended to predator—prey, parasite—host, and competitive population interactions. The energy constraints suggested by the genetic feedback model have significance for world food production and current agricultural practices including pest management and plant breeding.

Vole Cycles: Test of Another Hypothesis

Previous articleNext article No AccessLetters to the EditorsVole Cycles: Test of Another HypothesisGeorge O. Batzli and Frank A. PitelkaGeorge O. Batzli Search for more articles by this author and Frank A. Pitelka Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The American Naturalist Volume 109, Number 968Jul. - Aug., 1975 Published for The American Society of Naturalists Article DOIhttps://doi.org/10.1086/283019 Views: 2Total views on this site Citations: 10Citations are reported from Crossref Copyright 1975 The University of ChicagoPDF download Crossref reports the following articles citing this article:Eeva M. Soininen, Dorothée Ehrich, Nicolas Lecomte, Nigel G. Yoccoz, Arnaud Tarroux, Dominique Berteaux, Gilles Gauthier, Ludovic Gielly, Christian Brochmann, Galina Gussarova, Rolf A. Ims Sources of variation in small rodent trophic niche: new insights from DNA metabarcoding and stable isotope analysis, Isotopes in Environmental and Health Studies 50, no.33 (May 2014): 361–381.https://doi.org/10.1080/10256016.2014.915824Adam Kent, Susanne Plesner Jensen, C.Patrick Doncaster Model of microtine cycles caused by lethal toxins in non-preferred food plants, Journal of Theoretical Biology 234, no.44 (Jun 2005): 593–604.https://doi.org/10.1016/j.jtbi.2004.12.014S. K. Alibhai Effects of diet on reproductive performance of the Bank vole ( Clethrionomys glareolus ), Journal of Zoology 205, no.33 (Aug 2009): 445–452.https://doi.org/10.1111/j.1469-7998.1985.tb05629.xJudith H. Myers, Kathy S. Williams Does tent caterpillar attack reduce the food quality of red alder foliage?, Oecologia 62, no.11 (Apr 1984): 74–79.https://doi.org/10.1007/BF00377376S. Archer, L. L. Tieszen Effects of simulated grazing on foliage and root production and biomass allocation in an arctic tundra sedge (Eriophorum vaginatum), Oecologia 58, no.11 (Apr 1983): 92–102.https://doi.org/10.1007/BF00384547DAVID F. RHOADES Herbivore Population Dynamics and Plant Chemistry, (Jan 1983): 155–220.https://doi.org/10.1016/B978-0-12-209160-5.50012-X Robert H. Tamarin Dispersal, Population Regulation, and K-Selection in Field Mice, The American Naturalist 112, no.985985 (Oct 2015): 545–555.https://doi.org/10.1086/283296Thomas G. Hallam, Daniel S. Simberloff On the intrinsic structure of differential equation models of ecosystems, Ecological Modelling 3, no.33 (Aug 1977): 167–182.https://doi.org/10.1016/0304-3800(77)90027-8 Adam Łomnicki Evolution of Plant Resistance and Herbivore Population Cycles, The American Naturalist 111, no.977977 (Oct 2015): 198–200.https://doi.org/10.1086/283153Jay B Labov Phytoestrogens and mammalian reproduction, Comparative Biochemistry and Physiology Part A: Physiology 57, no.11 (Jan 1977): 3–9.https://doi.org/10.1016/0300-9629(77)90339-5