Source: CORNELL UNIVERSITY submitted to NRP
COMMUNITY AND EVOLUTIONARY ECOLOGY OF PLANT-INSECT INTERACTIONS
Sponsoring Institution
State Agricultural Experiment Station
Project Status
COMPLETE
Funding Source
STATE
Reporting Frequency
Annual
Accession No.
0201509
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Aug 24, 2004
Project End Date
Sep 30, 2009
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
CORNELL UNIVERSITY
(N/A)
ITHACA,NY 14853
Performing Department
ECOLOGY & EVOLUTIONARY BIOLOGY
Non Technical Summary
A central problem in ecology is disentangling the relative importance of current environmental conditions and evolutionary history in determining the structure of communities. This research project will employ diverse approaches to study this problem for insect herbivore communities on plants.
Animal Health Component
10%
Research Effort Categories
Basic
90%
Applied
10%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2062499107040%
2112499107040%
3143110107020%
Knowledge Area
206 - Basic Plant Biology; 211 - Insects, Mites, and Other Arthropods Affecting Plants; 314 - Toxic Chemicals, Poisonous Plants, Naturally Occurring Toxins, and Other Hazards Affecting Animals;

Subject Of Investigation
3110 - Insects; 2499 - Plant research, general;

Field Of Science
1070 - Ecology;
Goals / Objectives
Understanding the relative importance of factors that generate community structure and allow for the coexistence of species is central to ecological research. Insect herbivores have been a model for such research because of their high diversity and the relative ease with which they can be manipulated. Despite tremendous historical influence and the heated debate that ensued, systematic studies of the relative importance of multiple factors that control herbivore diversity and coexistence are rare. Especially important is the disentangling of the importance of current environmental conditions and historical evolutionary processes. Most theory predicts that trade-offs in fitness enhancing traits are necessary for species to coexist in communities. This research will evaluate multiple, non-exclusive hypotheses for trade-offs that maintain low populations of competitively dominant insects in the community of milkweed herbivores (ten species in five feeding guilds). We will test for the role of high susceptibility to predation, low colonization ability, variable preference and performance on plant genotypes that vary in defense, and specificity in induced plant responses (and effects on herbivores) as mechanisms of coexistence. Our previous work has demonstrated that plants exhibit high levels of intraspecific genetic variation and phenotypic plasticity in six defensive and nutritional traits, suggesting that the resource base for herbivorous insect communities is highly dynamic. This variation is predicted to be a key factor in the maintenance of diversity in herbivore communities. The explicit hypothesis is that trade-offs in the exploitation ability of herbivores on different plant phenotypes (generated by genetic variation or plasticity) allow variation in plant populations to maintain herbivore coexistence. Ultimately, an assessment of trade-offs promoting coexistence will be evaluated on several axes.
Project Methods
The research for this proposal is an integrated program to examine the mechanisms promoting coexistence of insect herbivores on milkweed plants, and will combine approaches from ecological genetics, chemical ecology, metapopulation biology, and phylogenetics. Of particular novelty is the combination of field experiments (quantitative analyses of plant and insect communities), ecological genetic analyses (the use of breeding designs to assess the heritability of plant defensive traits and their influence on insect community structure), plant defense assays (cardenolide concentration, latex production, leaf toughness, trichome density, water content, and nitrogen content), and phylogenetics (use of the systematic relationships between milkweed species to assess to the importance of evolutionary history in generating community patterns). The approach is highly integrative, in that such approaches are traditionally applied to ecological problems singly.

Progress 10/01/08 to 09/30/09

Outputs
OUTPUTS: We have continued to make tremendous progress on experiments and surveys of milkweed community ecology as well as outreach efforts to connect with K-12 educational units. We are in the final year of funding, and although we expect the project to continue, we are actively summing up many aspects of the project. On the experimental side, working with two postdoctoral fellows (both who have departed and entered permanent positions, one at the Smithsonian Environmental Research Center and the other at UC Irvine) and several undergraduate research assistants, we have completed six rigorous field experiments to examine the impact of various ecological factors (plant genetic variation, mutualistic ants, predation, phylogenetetic history, etc.) on the organization of the fauna of milkweed herbivores. In addition, we have completed two growth chamber experiments on multiple species of milkweeds. This work has resulted in several peer-reviewed publications (see below) and continuing work will elucidate the importance of variation among different species of milkweed. On the outreach side, this project supported a graduate student (Marc Lajeunesse) to participate in a Cornell Outreach Fellowship, which placed him in a 3rd grade classroom, and working with children on the appreciation of insect biodiversity. In addition, we have given several lectures and led field trips with the Cornell Institute for Biology Teachers. PARTICIPANTS: Anurag Agrawal (PI), Kailen Mooney (postdoctoral fellow), John Parker (postdoctoral fellow), Sergio Rasmann (postdoctoral fellow), Marc Lajeunesse (PhD student), Patricia L. Jones (undergraduate), R. Alex Smith (undergraduate), Kelly Goodsell (undergraduate), Jessica Goldstein (undergraduate), Ellen Woods (undergraduate), Daisy Johnson (undergraduate), Trey Ramsey (undergraduate). TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
This has primarily been in the arena of change in knowledge. Not only has this work contributed to the fundamental building of new knowledge about the ecology of plants, insects, and biodiversity more generally, but also the work has contributed to the training of two postdoctoral fellows, a graduate student (who has graduated and is now a postdoc at the prestigious National Evolutionary Synthesis Center), and seven undergraduates.

Publications

  • Agrawal, A. A., Salminen, J-P., and Fishbein, M. 2009. Phylogenetic trends in phenolic metabolism of milkweeds (Asclepias): Evidence for escalation. Evolution 63:663-673.
  • Futuyma, D. J. and Agrawal, A. A. 2009. Macroevolution and the biological diversity of plants and herbivores. PNAS 106:18054-18061.
  • Rasmann, S. and Agrawal, A. A. 2009. Plant defense against herbivory: Progress in Identifying synergism, redundancy, and antagonism between resistance traits. Current Opinion in Plant Biology 12:473-478.
  • Rasmann, S., Agrawal, A. A., Erwin, A. C., and Cook, S. C. 2009. Cardenolides, induced responses, and interactions between above and belowground herbivores in the milkweeds (Asclepias spp). Ecology 90:2393-2404.
  • Agrawal, A. A., Fishbein, M., Halitschke, R., Hastings, A. P., Rabosky, D. L., and Rasmann, S. 2009. Evidence for adaptive radiation from a phylogenetic study of plant defenses. PNAS 106:18067-18072.
  • Agrawal, A. A., Fishbein, M., Jetter, R., Salminen, J-P., Goldstein, J. B., Freitag, A. E., and Sparks, J. P.. 2009. Phylogenetic ecology of leaf surface traits in the milkweeds (Asclepias pp.): Chemistry, ecophysiology, and insect behaviour. New Phytologist 183:848-867.
  • Agrawal, A. A. and Konno, K. 2009. Latex: A model for understanding mechanisms, ecology, and evolution of plant defense against herbivory. Annual Review of Ecology, Evolution and Systematics 40:311-331.


Progress 10/01/07 to 09/30/08

Outputs
OUTPUTS: We have continued to make tremendous progress on experiments and surveys of milkweed community ecology as well as outreach efforts to connect with K-12 educational units. On the experimental side, working with two postdoctoral fellows (both who have departed and entered permanent positions, one at the Smithsonian Environmental Research Center and the other at UC Irvine) and several undergraduate research assistants, we have completed five rigorous field experiments to examine the impact of various ecological factors (plant genetic variation, mutualistic ants, predation, etc.) on the organization of the fauna of milkweed herbivores. In addition, we have completed two growth chamber experiments on multiple species of milkweeds. This work has resulted in several peer-reviewed publications and continuing work will elucidate the importance of variation among different species of milkweed. On the outreach side, this project supported a graduate student (Marc Lajeunesse) to participate in a Cornell Outreach Fellowship, which placed him in a 3rd grade classroom, and working with children on the appreciation of insect biodiversity. In addition, we have given several lectures and led field trips with the Cornell Institute for Biology Teachers. PARTICIPANTS: Anurag Agrawal (PI), Kailen Mooney (postdoctoral fellow), John Parker (postdoctoral fellow), Sergio Rasmann (postdoctoral fellow), Marc Lajeunesse (PhD student), Patricia L. Jones (undergraduate), R. Alex Smith (undergraduate), Kelly Goodsell (undergraduate), Jessica Goldstein (undergraduate), Ellen Woods (undergraduate). TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
This has primarily been in the arena of change in knowledge. Not only has this work contributed to the fundamental building of new knowledge about the ecology of plants, insects, and biodiversity more generally, but also the work has contributed to the training of two postdoctoral fellows, a graduate student (who has graduated and is now a postdoc at the prestigious National Evolutionary Synthesis Center), and five undergraduates.

Publications

  • Agrawal, A. A., Erwin, A. C., and Cook, S. C. 2008. Natural selection and predicted response for ecophysiological traits of swamp milkweed (Asclepias incarnata) in the field. Journal of Ecology 96:536-542.
  • Agrawal, A. A. and Fishbein, M. 2008. Phylogenetic escalation and decline of plant defense strategies. PNAS 105:10057-10060.
  • Agrawal, A. A., Lajeunesse, M. J., and Fishbein, M. 2008. Evolution of latex and its constituent defensive chemistry in milkweeds (Asclepias): A test of phylogenetic escalation. Entomologia Experimentalis et Applicata 128:126-138.
  • Mooney, K. A. and Agrawal, A. A. 2008. Plant genotype shapes ant-aphid interactions: Implications for community structure and indirect plant defense. American Naturalist 171:E195-E205.
  • Mooney, K. A., Jones, P., and Agrawal, A. A. 2008. Coexisting congeners: Demography, competition, and interactions with cardenolides for two milkweed-feeding aphids. Oikos 117:450-458.
  • Rasmann, S. G. A. and Agrawal, A. A. 2008. In defense of roots: A research agenda for studying plant resistance to below ground herbivory. Plant Physiology 146:875-880.
  • Smith, R. A., Mooney, K. A., and Agrawal, A. A. 2008. Coexistence of three specialist aphids on the common milkweed Asclepias syriaca. Ecology 89:2187-2196.


Progress 10/01/06 to 09/30/07

Outputs
OUTPUTS: We have continued to make tremendous progress on experiments and surveys of milkweed community ecology as well as outreach efforts to connect with K-12 education. On the experimental side, working with two postdoctoral fellows and undergraduate research assistants, we have completed five rigorous field experiments to examine the impact of various ecological factors (plant genetic variation, mutualistic ants, predation, etc.) on the organization of the fauna of milkweed herbivores. This work has resulted in several peer-reviewed publications and continuing work will elucidate the importance of variation among different species of milkweed. On the outreach side, this project supported a graduate student (Marc Lajeunesse) to participate in a Cornell Outreach Fellowship, which placed him in a third grade classroom, and working with children on the appreciation of insect biodiversity. PARTICIPANTS: Anurag Agrawal (PI), Kailen Mooney (Postdoctoral Fellow), John Parker (Postdoctoral Fellow), and Marc Lajeunesse (Ph.D. Candidate).

Impacts
This has primarily been in the arena of change in knowledge. Not only has this work contributed to the fundamental building of new knowledge about the ecology of plants, insects, and biodiversity more generally, but the work has contributed to the training of two postdoctoral fellows (now both in permanent positions), a continuing graduate student, and two undergraduates.

Publications

  • Johnson, M. T. J. and Agrawal, A. A. 2007. Covariation and composition of arthropod species across plant genotypes of evening primrose, Oenothera biennis. Oikos 116:941-956.


Progress 01/01/06 to 12/31/06

Outputs
We made major advances this year on the project. My postdoctoral associates, Kailen Mooney and John Parker, worked with me extensively on the project over the summer collecting data on five separate sub-projects. They are: (1) Evolutionary ecology of swamp milkweed (Asclepias incarnata); (2) Quantitative genetics experiments to examine the effects of ants and plant genetic family on aphid population and community dynamics: (3) Effects of deer and molluskan herbivores on plant invasions; (4) Effects of geese and insects on the success of Eurasian water milfoil; and (5) Comparative biology of defense in the milkweeds. Each of these sub-projects involves field experiments and laboratory work assessing the interactions between plants and their herbivores. Some of this work is relevant to the understanding and protection of biodiversity, the environmental impacts of invasive species, and the assessment of successful types of natural defense strategies that could be employed in agriculture. We have written and submitted several papers from this work in addition to what has been published. This winter we have been analyzing data and maintaining laboratory colonies of the plants and insects to work on some of the smaller laboratory objectives. We continue to involve undergraduates in our research and expect these students to be coauthors on forthcoming papers.

Impacts
We are collaborating with local naturalists, nurseries, and hobbyists, including the Cayuga Land Trust, to raise awareness and interest in the interactions between meadow plants and insects.

Publications

  • Mitchell, C.E., Agrawal, A.A., Bever, J.D., Gilbert, G.S., Hufbauer, R.A., Klironomos, J.N., Maron, J.L., Morris, W.F., Parker, I.M., Power, A.G., Seabloom, E.W., Torchin, M.E. and Vazquez, D.P. 2006. Biotic interactions and plant invasions. Ecology Letters 9:726-740.
  • Agrawal, A.A. and Fishbein, M. 2006. Plant defense syndromes. Ecology 87:S132-S149.
  • Agrawal, A.A., Lau, J.A. and Hamback, P.A. 2006. Community heterogeneity and the evolution of interactions between plants and insect herbivore. Quarterly Review of Biology 81:349-376.
  • Johnson, M.T.J, Lajeunesse, M.J. and Agrawal, A.A. 2006. Additive and synergistic effects of plant genotypic diversity on arthropod communities and plant fitness. Ecology Letters 9:24-34.


Progress 01/01/05 to 12/31/05

Outputs
We made major advances this year on the project. My postdoctoral associate, Kailen Mooney, and I worked extensively on the project over the summer, setting up a long-term common garden experiment of Swamp Milkweed (Asclepias incarnata) and several quantitative genetics experiments to examine the effects of ants and plant genetic family on aphid population and community dynamics. This winter we have been analyzing data and maintaining laboratory colonies of the plants and insects to work on some of the smaller laboratory objectives.

Impacts
We are collaborating with local naturalists, nurseries, and hobbyists, including the Cayuga Land Trust, to raise awareness and interest in the interactions between meadow plants and insects.

Publications

  • Agrawal, A.A. 2005. Natural selection on common milkweed (Asclepias syriaca) by a community of specialized insect herbivores. Evolutionary Ecology Research 7:651-667.
  • Johnson, M.T.J. and Agrawal, A.A. 2005. Plant genotype and the environment interact to shape a diverse arthropod community on evening primrose (Oenothera biennis). Ecology 86:874-885.
  • Agrawal, A.A., Kotanen, P.M., Mitchell, C.E., Power, A.G., Godsoe, W. and Klironomos, J. 2005. Enemy release. An experiment with congeneric plant pairs and diverse above and below-ground enemies. Ecology 86:2979-2989.


Progress 01/01/04 to 12/31/04

Outputs
Since this project's inception (08/24/04), we have mainly been in the start-up and design stages. We have collected the seeds of many milkweed species and genetic families within two common local species. In addition, plant culture and insect rearing has begun. Our formal experiment will begin this spring.

Impacts
We are working with local naturalists, nurseries, and hobbyists to raise awareness and interest in the interactions between meadow plants and insects. This has already led to collaborations.

Publications

  • No publications reported this period