Source: VIRGINIA COMMONWEALTH UNIVERSITY submitted to NRP
OUTBREAKS OF INSECT PESTS: CLIMATE DRIVERS AND IMPACTS OF CLIMATE CHANGE
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
Reporting Frequency
Annual
Accession No.
1007844
Grant No.
2016-67012-24694
Cumulative Award Amt.
$127,735.00
Proposal No.
2015-03685
Multistate No.
(N/A)
Project Start Date
Dec 15, 2015
Project End Date
Dec 14, 2018
Grant Year
2016
Program Code
[A7201]- AFRI Post Doctoral Fellowships
Recipient Organization
VIRGINIA COMMONWEALTH UNIVERSITY
(N/A)
RICHMOND,VA 23298
Performing Department
Biology
Non Technical Summary
Outbreaks of agricultural and forest insect pests have significant economic and ecological impacts, but drivers of pest population dynamics, including the roles of climate and management, are often not well understood. Early reports on the effects of climate change warned of widespread increases in the frequency and severity of pest outbreaks, but these warnings have proven to be overgeneralizations. More recent studies have detected a wide range of pest responses to climate change, from outbreaks of unprecedented severity, to a recent cessation of outbreaksthat had occurred in consistent cyclesfor over 1100 years. Pest species are also subject to human interventions intended to limit their negative impacts, but knowledge of how management interventions, such as pesticide application, influence pest populations over the long term is limited. The overall goal of this project is to elucidate the effects of climate and management on the outbreaks of agricultural and forest insect pests. Doing so is vital to adapting forest management and agricultural practices to the effects of climate change, and to predicting whether insects that are currently not important pests could become significant pests in future climates.The methodological approach of this project has several components. First, a database will be compiled that describes how the abundance of >40 insect pest species, in multiple locations representing seven regions of the US, has changed through time. These data will be collected from published studies, public repositories, and groups such as state agricultural extensions. Analysis of the database will occur in four main steps. First, historical pest population patterns will be characterized, focusing on two questions. Overall, is the population increasing, decreasing, or staying the same? And, does the pest experience recurring outbreaks, and if so are they changing in their frequency or severity? Second, climate and management drivers of pest population dynamics will be evaluated. To improve insights into the underlying mechanisms that lead to changes in pest abundance, changes in abundance will be statistically decomposed into two factors that, respectively, represent the direct effects of environmental conditions, and effects that are mediated through interactions with other organisms, such as competition and predation. Then, relationships between each of these factors and variables representing climate and management effort will be quantified to investigate how climate and management affect the long-term population dynamics of insect pests. Third, the hypothesis that similar species respond similarly to climate change will be tested by statistically searching for characteristics of life history, ecology, and geography that are associated with a species' response to climate change, for example whether its abundance is increasing or declining. If effective, this approach could be used to predict general responses of pest species for which little data is available, or to identify species that are not currently abundant but could emerge as significant pests in the future. The fourth and final step is to predict the potential future impact of these pests. Results from previous analytical steps will inform the development of models of how climate affects changes in pest abundance, which will be applied to projections from a suite of climate models to predict the frequency and severity of pest outbreaks between the present day and the year 2050.The ultimate goal of this project is to elucidate how climate variability, climate change, and management effort influence insect outbreaks. This question has significant socioeconomic implications given the negative impacts of insect pests on food production, forestry, outdoor recreation, and homeowner expenditures and property values. Improved understanding of underlying patterns and drivers of insect outbreaks, and their potential to change in future climates, is expected to inform adaptive strategies that limit these adverse impacts and improve the security and sustainability of agricultural and forest production.
Animal Health Component
(N/A)
Research Effort Categories
Basic
100%
Applied
(N/A)
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
21131101070100%
Knowledge Area
211 - Insects, Mites, and Other Arthropods Affecting Plants;

Subject Of Investigation
3110 - Insects;

Field Of Science
1070 - Ecology;
Goals / Objectives
The overarching goal of this project is to assess how climate variability and change influence the population dynamics of outbreaking agricultural and forest pests. Toward that end, four specific objectives are as follows:Characterize recent population dynamic patterns of insect pests.Quantify how climate and management effort (e.g., pesticide application) drive pest population dynamics.Evaluate whether life history and ecological characteristics can predict how a species' populations will respond to climate change.Project effects of pests on crop and forest production out to the year 2050.
Project Methods
Research Methods:The overall approach involves 1) compiling an extensive database documenting how the abundance of forest and agricultural pests has changed through time at multiple locations in seven regions of the US; 2) analyzing that database to characterize trends and cyclical behavior in population dynamics; 3) quantifying how climate and management effort affect pest population dynamics and outbreak occurrence; 4) evaluating whether characteristics of ecology, life history, and geography can predict how a pest will respond to climate change; and 5) projecting future pest outbreak dynamics under different climate change scenarios, out to the year 2050. The pest database will be compiled through a combination of published and publically available sources, as well as data requests to specific groups, such as state agricultural extensions.Trends in pest abundance will be quantified using modified regression methods. Population cycles will be evaluated using wavelet analyses. Climate and management drivers of pest outbreaks will be quantified by first decomposing changes in pest abundance into density-independent and density-dependent factors using time-varying autoregressive models; associations between these factors andclimate and management will then be evaluated using regression methods. Conditional inference trees will be used to evaluate if and which characteristics of ecology, life history, and geography can be used to predict pest responses to climate change. Future pest oubreak dynamics will be projected by running models fit to historical data over climate projections from CMIP-5 climate models.Efforts:Results from this research will be disseminated through presentations at relevant conferences and publication in peer-reviewed scientific journals. Mentored undergraduate researchers will recieve training in the process of scientific inquiry and skills in data analysis and population modeling, and contribute to the goals and objectives of this research project. Classroom instruction will be used to introduce students to broader principles in population ecology, with lessons on climate change and pest population outbreaks.Evaluation:This project will be evaulated in terms of timely completion of project milestones, dissemination of reserch findings, and indicators of the postdoctoral fellow (PD)'s professional development. In Year 1, we will compile the pest population database, characterize recent patterns of outbreak dynamics, and make substantial progress toward quantifying climate and management drivers of pest populations. In Year 2, we will complete quantification of climate and management drivers, evaluate characteristics predictive of responses to climate change, and project future pest outbreak dynamics. To disseminate research findings, the PD will present research at the 2016 meeting of the Entomological Society of America and the 2017meeting of the Ecological Society of America. We expect this project to yield at least three articles in peer-reviwed scientific journals. Professional development with respect to the PD's mentoring and teaching abilitieswill be indicated based on feedback from the primary mentor, Dr. Derek Johnson, and formal evaluations by course students and research mentees.

Progress 12/15/17 to 12/14/18

Outputs
Target Audience:Academic scientists, state and federal agency officials involved in agriculture and natural resource management. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?I have been able to collaborate with a much wider group of scientists than had I not received this fellowship, which has had a snowball-effect on the size of my professional network and the amount and breadth of science I have produced in the past three years. How have the results been disseminated to communities of interest?I have presented my work at several scholarly conferences in ecology, entomology, and conservation biology. I have also worked extensively with pest managers as part of the Gypsy Moth Slow the Spread Foundation Technical Committee and as a member of the National Gypsy Moth Management Board. What do you plan to do during the next reporting period to accomplish the goals?The grant period has ended.

Impacts
What was accomplished under these goals? Objectives 1 and 3 were addressed in Walter et al. (2018) Life history and habitat explain variation among insect populations subject to global change. Objective 2 was addressed, for a selection of taxa having high-quality data, in Walter et al. (submitted) Effects of weather and transgenic, insect-resistant crops on spatial synchrony and multi-decadal population trends of Lepidopteran pests. Objective 4 could not be completed because the data I was able to assemble could not enable robust predictions of future population dynamics.

Publications

  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Anderson, T.L., L.W. Sheppard, J.A. Walter, S.P. Hendricks, K.A. Johnston, T.L. Levine, D.S. White, & D.C. Reuman. 2018. The dependence of synchrony on timescale and geography in freshwater plankton. Limnology and Oceanography doi: 10.1002/lno.11054.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Malfi, R.M., J.A. Walter, T.H. Roulston, C. Stuligross, S. McIntosh, & L. Bauer. 2018. The influence of a prominent natural enemy on bumblebee colony productivity. Ecological Monographs 88, 653-671.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Klaapwijk, M.J., J.A. Walter, A. Hirka, G. Csoka, C. Bjorkman, & A.M. Liebhold. 2018. Transient synchrony among fiver foliage-feeding Lepidoptera. Journal of Animal Ecology doi: 10.1111/1365-2656.12832.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Zhao, L., L.W. Sheppard, P.C. Reid, J.A. Walter, & D.C. Reuman. 2019. Proximate determinants of Taylor's Law slopes. Journal of Animal Ecology doi: 10.111/1365-02656.12931.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Anderson, T.L., J.A. Walter, T.D. Levine, S.P. Hendricks, K.A. Johnston, D.S. White, & D.C. Reuman. 2018. Using geography to infer the importance of dispersal for the synchrony of freshwater plankton. Oikos 127:402-414.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Walter, J.A., A.R. Ives, J.F. Tooker, & D.M. Johnson. 2018. Life history and habitat explain variation among insect populations subject to global change. Ecosphere doi: 10.1002/ecs2.2274.
  • Type: Journal Articles Status: Under Review Year Published: 2019 Citation: Karki, G., & J.A. Walter. In review. Spatial and temporal patterns of non-native fruit fly detections in California, USA. PeerJ.
  • Type: Journal Articles Status: Under Review Year Published: 2019 Citation: Walter, J.A., K.L. Grayson, L.M. Blackburn, P.C. Tobin, & D.M. Johnson. In review. Spatiotemporal variability in Allee effects of invading gypsy moth populations. Biological Invasions.
  • Type: Journal Articles Status: Other Year Published: 2019 Citation: Sheppard, L.W., B. Mechtley, J.A. Walter, & D.C. Reuman. Under revision following review. Self-organizing cicada choruses respond to the local sound and light environment.
  • Type: Journal Articles Status: Under Review Year Published: 2019 Citation: Haynes, K.J., J.A. Walter, & A.M. Liebhold. In review. Population periodicity and low detuning with environmental forcing promote spatial synchrony among gypsy moth populations. Proceedings of the Royal Society B.
  • Type: Journal Articles Status: Submitted Year Published: 2019 Citation: Anderson, T.L., L.W. Sheppard, R.E. Rolley, & D.C. Reuman. Submitted. Synchronous effects produce major cycles in deer populations and deer-vehicle collisions. Science.
  • Type: Journal Articles Status: Submitted Year Published: 2019 Citation: Walter, J.A., P.D. Venugopal, L.W. Sheppard, D.C. Reuman, G. Dively, J.F. Tooker, & D.M. Johnson. Submitted. Effects of transgenic, insect-resistant crops on spatial synchrony and multi-decadal population trends of Lepidopteran pests. Agriculture, Ecosystems & Environment.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2018 Citation: Walter, J.A., A.R. Ives, J.F. Tooker, and D.M. Johnson. Life history and habitat explain variation among insect populations subject to global change. Entomology 2018, Vancouver, CA. Invited Talk.


Progress 12/15/15 to 12/14/18

Outputs
Target Audience: Academic scientists, state and federal agency officials involved in agriculture and natural resource management. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This fellowship gave me much greater ownership over my career and allowed me to develop new collaborations. Beyond the core goals of this grant, I worked with Dan Reuman's lab at the University of Kansas to develop and apply new statistical tools for the study of synchrony in ecology. Synchrony has major importance to outbreaks of pests and disease. Some of these techniques were applied in the in-review manuscript addressing Goal 2, and have also been applied to gypsy moth outbreaks (Walter et al. 2017 "The geography of spatial synchrony"; five lepidopteran pests in Hungarian forests (Klaapwijk et al. 2018 "Transient synchrony among five foliage-feeding lepidoptera"; Haynes et al. in review "Population periodicity and low detuning with environmental forcing promote spatial synchrony among gypsy moth populations". I was able to travel to conferences and visit collaborators, which helped expand my network and develop new collaborations. How have the results been disseminated to communities of interest?I have published 14 and submitted 7 manuscripts during the grant period. I have given several talks at scientific and management-focused meetings. My collaborators include scientists with extension appointments who can use our research to bring added context to their extension work. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Goals 1 and 3 were addressed in Walter et al. (2018) "Life history and habitat explain variation among insect populations subject to global change." We characterized the multi-decadal population dynamic patters of >60 insect pests subject to changes in climate, land use, and agricultural and forestry practices, and showed that aspects of geography and life history could explain similarities in population dynamics. I found over the course of this project that limitations on data quality and availability made attributing patterns to specific mechanisms was not systematically possible. So Goal 2 was addressed using a subset of 16 agricultural pests having particularly good data. This work is currently in review at Agiculture, Ecosystems, & Environment. We found that changes in agriculture in the 1990s, largely related to the introduction of transgenic crops, caused changes in long-term population trends for many species. Synchronous, state-wide outbreaks of these pests were often related to spring and summer weather conditions.

Publications


    Progress 12/15/16 to 12/14/17

    Outputs
    Target Audience:Scientists and resource managers Changes/Problems:I am unable to achieve Goal 4, projecting future impacts of crop and forest pests under climate change because the data did not allow the robust fitting of statistical models suitable to projecting future pest impacts under varying climatic conditions. I have turned my attention to studying spatial synchrony in insect outbreaks and other phenomena. Spatial synchrony is the quality of insect (and disease) outbreaks that characterizes their wide-spread, simultaneous damaging effects, and hence understanding causes of spatial synchrony has major fundamental science and applied significance. What opportunities for training and professional development has the project provided?I spent a week visiting the lab of a collaborating mentor, Tony Ives at the University of Wisconsin-Madison, where I had the opportunity to work on analyses and network with members of his lab and other scientists at UW. Running my own research program, and having funding to support travel, has provided immense flexibility to develop new collaborations with several scientists. How have the results been disseminated to communities of interest?I have published 6 scientific papers and given several invited seminars at research institutions. I am a member of the Gypsy Moth Slow the Spread Foundation Technical committee, the scientific advisory board to the organization coordinating state and federal efforts to contain the gypsy moth invasion. Here I use my research expertise to advise a science-based management plan responding to changes in spread dynamics and funding restrictions. What do you plan to do during the next reporting period to accomplish the goals?I will focus on publishing manuscripts reporting findings from goals 1-3 and 7 other in-prep manuscripts I have led or collaborated on with support from NIFA.

    Impacts
    What was accomplished under these goals? Goals 1, 2, and 3 have been addressed and manuscripts describing research findings are in review, or at the manuscript stage and being prepared for submission; see references below. Given the outcomes of goals 1-3, goal 4 proved to be unfeasible, and so attention was turned to other research avenues related to impacts of climate on population dynamics and the stability of ecological communities. Walter, JA, AR Ives, JF Tooker, DM Johnson (in review) Life history and habitat explain variation among insect populations subject to global change. Walter, JA, JF Tooker, DM Johnson (in prep) Long-term suppression of multiple lepidopteran pests by transgenic, insect-resistant crops.

    Publications

    • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Walter, JA, LM Hallett, LW Sheppard, RJ Hobbs, KN Suding, DC Reuman (2017) Variation in spatial synchrony in a serpentine plant community. Ecological Society of America Annual Meeting, Portland, OR. Oral Presentation.
    • Type: Journal Articles Status: Awaiting Publication Year Published: 2017 Citation: Anderson, TL, JA Walter, TD Levine, SP Hendricks, KA Johnston, DS White, DC Reuman (in press) Using geography to infer the importance of dispersal for the synchrony of freshwater plankton. Oikos.
    • Type: Journal Articles Status: Accepted Year Published: 2017 Citation: Walter, JA, LW Sheppard, TL Anderson, JH Kastens, ON Bjornstad, AM Liebhold, DC Reuman (2017) The geography of spatial synchrony. Ecology Letters. doi: 10.1111/ele.12782.
    • Type: Journal Articles Status: Published Year Published: 2017 Citation: Walter, JA, JC Neblett, JW Atkins, HE Epstein (2017) Regional and watershed scale analysis of red spruce habitat in the southeastern United States: implications for future restoration efforts. Plant Ecology 218, 305-316.
    • Type: Journal Articles Status: Accepted Year Published: 2017 Citation: Foster, AE, JA Walter, J Siebold, JF Negron, HH Shugart (2017) Spectral evidence of early-stage spruce beetle infestation in Engelmann spruce. Forest Ecology and Management 384: 347-357.
    • Type: Journal Articles Status: Published Year Published: 2017 Citation: JA Walter, KL Grayson, DM Johnson (2017) Variation in Allee effects: evidence, unknowns, and directions forward. Population Ecology. doi: 10.1007/s10144-0576-3.
    • Type: Journal Articles Status: Published Year Published: 2016 Citation: Walter, JA, AL Firebaugh, PC Tobin, KJ Haynes (2016) Invasion in patchy landscapes is affected by dispersal mortality and mate-finding failure. Ecology 97:3389-3401.
    • Type: Journal Articles Status: Under Review Year Published: 2017 Citation: Anderson, TL, LW Sheppard, JA Walter, SP Hendricks, KA Johnston, TL Levine, DS White, DC Reuman (in review) Differentiating mechanisms of spatial synchrony in freshwater plankton. Limnology and Oceanography.
    • Type: Journal Articles Status: Under Review Year Published: 2017 Citation: Klaapwijk, MJ, JA Walter, A Hirka, G Csoka, C Bjorkman, AM Liebhold (in review) Transient synchrony among five foliage-feeding Lepidoptera. Journal of Animal Ecology
    • Type: Journal Articles Status: Under Review Year Published: 2017 Citation: JA Walter, AR Ives, J Tooker, DM Johnson (in review) Life history and habitat explain variation among insect populations subject to global change. Proceedings of the Royal Society-B
    • Type: Journal Articles Status: Under Review Year Published: 2017 Citation: Zhao, L, LW Sheppard, PC Reid, JA Walter, DC Reuman (in review) Proximate determinants of Taylor's law slopes. Ecology.


    Progress 12/15/15 to 12/14/16

    Outputs
    Target Audience:Target audiences reached during this reporting period are scientists, managers, and students. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project has facilitated significant professional development opportunities as follows: expanding my network of collaborators, grantwriting, and mentorship of an undergraduate student researcher. How have the results been disseminated to communities of interest?A subset of results relevant to this project was presented at the annual meeting of the Ecological Society of America. In the process of building the pest database, I reached out to many extension agents who are now aware that this research is being conducted. A number of publications related to pest population dynamics, invasive insects, and climate change have been submitted to peer-reviewed journals. I mentored an undergraduate research student, who produced a publication-quality study on invasive fruit flies, which we plan to submit for publication in early 2017. What do you plan to do during the next reporting period to accomplish the goals?I will continue analyzing the pest database I assembled to complete goals 1-3 and prepare manuscripts for publication. I will present results at the 2017Entomological Society of America conference. I will use results from goals 1-3 to develop the models to achieve goal 4.

    Impacts
    What was accomplished under these goals? Substantial progress toward objectives 1, 2 and 3 have been achieved, and submission of a manuscript representing a subset of these findings is anticipated by the end of 2016. I have documented a range of changes to pest population dynamics during recent decades, and evidence that pest characteristics may predict some patterns of change.

    Publications

    • Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: Walter, J.A., L.W. Sheppard, J.H. Kastens, A.M. Liebhold, and D.C. Reuman. Biogeography of gypsy moth defoliation synchrony in the Northeastern US. Ecological Society of America, Ft. Lauderdale, FL, August 11, 2016. Oral presentation.
    • Type: Journal Articles Status: Awaiting Publication Year Published: 2016 Citation: Walter, J.A., A.L. Firebaugh, P.C. Tobin, and K.J. Haynes. (in press). Invasion in patchy landscapes is affected by dispersal mortality and mate-finding failure. Ecology.
    • Type: Journal Articles Status: Awaiting Publication Year Published: 2016 Citation: Foster, A.E., J.A. Walter, J. Siebold, J.F. Negron, and H.H. Shugart. (in press). Spectral evidence of early-stage spruce beetle infestation in Engelmann spruce. Forest Ecology and Management.
    • Type: Journal Articles Status: Under Review Year Published: 2016 Citation: Walter, J.A., J.C. Neblett, J.W. Atkins, and H.E. Epstein. (in review). Regional and watershed scale analysis of current and future suitable habitat for red spruce in the Central Appalachian Mountains.
    • Type: Journal Articles Status: Under Review Year Published: 2016 Citation: Walter, J.A., K.L. Grayson, and D.M. Johnson. (in review). Variation in Allee effects: evidence, unknowns, and directions forward.