Although most introduced insects are relatively benign, some become high-impact pests causing widespread ecological and economic damage. Introduced insects that are specialists and feed on a single genus of plants can be high-impact as they can potentially eliminate an entire native plant genus over large areas. Luckily, most introduced insects with this feeding behavior do not become high-impact pests. However, there is great need to predict, prior to their introduction, which insects have the potential to result in high-impact invasions so risk assessment and management are informed.
A group of USGS, Forest Service, and university scientists are working together to study how ecology and evolution might be used to understand when introduced insects become high-impact. We are examining the contribution of five types of drivers toward these impacts: (1) the insects’ and host plants’ evolutionary history, (2) the hosts’ defenses or lack thereof (defense-free space), (3) presence of natural enemies or lack thereof (enemy release), (4) invader traits, and (5) geographic and temporal considerations.
Background & Importance
Within their native range, where the insects and their host plants evolved together (coevolution), host plants develop effective defenses that limit insect feeding. Plants are often less resistant to introduced insects when a coevolutionary history with the insects is lacking; they are considered to be evolutionarily naïve. Many examples of invasions in North America that have caused wide-spread death of native plants, are introduced insects that specialize on feeding on a particular genus of plants that are evolutionarily naïve to that insect. In order words the plant lacks defenses to the insects feeding on them.
Introduced insects also may have the benefit of release from their natural enemies that are present in their native environment. Release of natural enemies is often provided as a reason for the ability of the introduced insect to persist and spread. However, release from natural enemies provides only a partial explanation for invasion success. A far less-studied mechanism is the defense-free space hypothesis that states it is insufficient defenses of the host plants that allow the invading insect to thrive. Researchers have demonstrated the importance of including the lack of coevolved defenses in establishing the risk of invasion, they have not sufficiently incorporated the role of coevolved plant defenses into explanations of impacts of invasion.
General Methods
The USGS Powell Center sponsors researchers to meet and work together on a problem. Our working group has been addressing this problem through telephone conferences in late 2015 and 2016 and our first in person work meeting in Fort Collins in July 2016. We plan to continue our work throughout 2017 and 2018 and have planned our second week long in person work meeting in August of 2017.
We are focusing on introduced insects in North America that feed on native plants. The project has three implementation components data compilation and synthesis, model development and validation, and model evaluation and application. The conceptual diagram of drivers of invasive insect impact (see image) will guide our initial selection of introduced species and their representative traits and factors. These traits and factors will serve as predictor variables incorporated into and tested in a statistical model predicting invasion impact. Lastly, we will apply the parameterized model to insects not yet established in the U.S. to develop a probability ranking of those insects likely to become significant threats if introduced.
References Cited
Gurevitch, J., Fox, G.A., Wardle, G.M., Inderjit, and Taub. D., 2011, Emergent insights from the synthesis of conceptual frameworks for biological invasions: Ecology Letters, v.,14, p. 407-418.
Recent Presentations
- Schulz, A.N., A.M. Mech, M.P. Ayres, K.J.K. Gandhi, N.P. Havill, D.A. Herms, A. Hoover, A.M. Liebhold, T.D. Marsico, K.F. Raffa, K.A. Thomas, P.C. Tobin, D.R. Uden, and R.A. Hufbauer. November 2020. Which factors drive impact of introduced insects feeding on North American conifers and woody angiosperms? The data speak. 68th Annual Meeting of the Entomological Society of America. Virtual Conference.
- Mech, A.M., K.A. Thomas, T.D. Marsico, D.A. Herms, C.R. Allen, M.P. Ayres, K.J.K. Gandhi, J. Gurevitch, N.P. Havill, R.A. Hufbauer, A.M. Liebhold, K.F. Raffa, A.N. Schulz, D.R. Uden, and P.C. Tobin. 2020. How available data can be used to predict the impact of non-native forest insects. Society of American Foresters National Convention. Virtual Conference. Conference talk.
- Thomas, K.A., A.M Mech, P.C. Tobin, D.A. Herms, M.P. Ayres, N.P. Havill, C.R. Allen, K.J.K. Gandhi, J. Gurevitch, A. Hoover, R.A. Hufbauer, A.M. Liebhold, K.F. Raffa, A.N. Schulz, D.R. Uden, and T.D. Marsico. 2020. Predicting the impact of non-native insects on forest trees: The data speak. North American Invasive Species Management Association (NAISMA). Virtual conference. Conference talk.
- Thomas, K.A., Mech, A.M., Ayers, M.P. Tobin, P.C., Herms, A., Havill, N.P., Uden, Da. Schulz, A. N., Allen, C.R., Gandhi, K.J.K. Gurevitch, J., Hoover, A., Hufbauer, R.A., Liebhold, A.M., Raffa, K.F., and Marsico, T. D. 2020. Predicting the impact of non-native insects: The data speak. Ecological Society of America, August 3-7, 2020. Virtual venue. IP 119465 2020/05/27
- Thomas, K.A. 2020. Predicting the impact of non-native tree-feeding insects on North American trees. USGS Southwest Biological Science Center Sweet Science. Seminar talk.
- Mech, A.M. Searching for the holy grail of invasions – What if we could predict the impact of non-native insects? 2018. 27th Annual Southern Appalachian Forest Entomologist/Pathologist Seminar. March 2018. Crossnore, NC. Seminar talk.
- Mech, A.M., Herms, D.A., Marsico, T.D., Thomas, K.A., and Tobin, P.C. 2018. “Predicting the impact of non-native specialist insects”. 29th USDA Interagency Research Forum on Invasive Species, January 2018, Annapolis, Maryland. Conference talk.
- Schulz, A.N., Mech, A.M., Allen, C.R., Ayres, M.P., Gandhi, K.J.K., Gurevitch, J., Havill, N.P. Herms, D.A., Hufbauer, R.A., Liebhold, A.M., Raffa, K.F., Raupp, M.J., Thomas, K.A., Tobin, P.C., and Marsico, T.D. 2018 “Assessment of Expert Perceptions of Non-Native Insect Impacts: Implications for Policy and Management”. Missouri Natural Resources Conference. January 2018. Osage Beach, Missouri. Conference poster.
- Mech, A.M., Herms, D.A., Marsico, T.D., Thomas, K.A. and Tobin, P.C. 2018. “Using evolutionary history to help identify high-impact non-native herbivorous specialist insects prior to their arrival.” Entomological Society of America (ESA), Entomological Society of Canada (ESC) and Entomological Society of British Columbia (ESBC) Joint Annual meeting. November 2018. Vancouver, British Columbia. Conference talk.
- Schulz, A.N., Mech, A.M., Allen, C.R., Ayres, M.P., Gandhi, K.J.K., Gurevitch, J., Havill, N.P. Herms, D.A., Hufbauer, R.A., Liebhold, A.M., Raffa, K.F., Raupp, M.J., Thomas, K.A., Tobin, P.C., and Marsico, T.D. 2018. “Do All Great Minds Think Alike? An Assessment of Expert Perspective on the Impacts of Non-Native Insects in North America”. Entomological Society of America (ESA), Entomological Society of Canada (ESC) and Entomological Society of British Columbia (ESBC) Joint Annual meeting. November 2018. Vancouver, British Columbia. Conference virtual poster.
- Thomas, K.A., Mech, A., Hoover, A., and Tobin, P., Allen, C., Ayers, M., Gandhi, K, Gurevitch, J., Havill, N., Herms, D., Hufbauer, R., Liebhold, A., Marsico, T., Raffa, K., Schulz, A. and Uden, D. 2018. “Traits and factors of non-native phytophagous insects in North America: The TRAFAC database”. Entomological Society of America (ESA), Entomological Society of Canada (ESC) and Entomological Society of British Columbia (ESBC) Joint Annual meeting. November 2018. Vancouver, British Columbia. Conference poster.
- Liebhold, A.M. Mech, A.M., Allen, C.R., Ayres, M.P., Gandhi, K.J.K., Gurevitch, J., Havill, N.P. Herms, D.A., Hufbauer, R.A., Raffa, K.F., Raupp, M.J., Schulz, A.N., Thomas, K.A., Tobin, P.C., and Marsico, T.D. et al. 2017. Predicting the Impact of Non-Native Specialist Insects Feeding on North American Host Plants, COST Action FP1401 - A global network of nurseries as early warning system against alien tree pests - Working Group and Management Committee Meeting, Offenburg, Germany. Conference talk.
- Mech, A., P.C. Tobin, T.D. Marsico, K.A. Thomas, D.A. Herms, C.R. Allen, M.P. Ayres, K.J.K. Gandhi, J. Gurevitch, N.P. Havill, A. Hoover, R.A. Hufbauer, A.M. Liebhold, K.F. Raffa, M.J. Raupp, A.N. Schulz, and D. Uden. August 2017. Predicting the next high-impact insect invasion. USGS John Wesley Powell Center for Analysis and Synthesis Seminar Series. Ft. Collins, CO. Seminar talk.
- Thomas, K.A., Mech, A., Herms, D.A., Marsico, T., and Tobin, P. 2017. “Establishing traits that may determine the impacts of introduced herbivorous insects on North American (NA) conifers” Pacific Branch Entomological Society of America Annual Meeting. April 2017. Portland, Oregon. Conference talk.
- Mech, A.M., Marsico, T.D., Thomas, K.A., Herms, D.A., and Tobin, P.C. 2017. “Predicting the Impact of Non-Native Specialist Insects Feeding on North American Host Plants” Ecological Society of America Annual Meeting. August 2017. Portland, Oregon. Conference talk.
- Tobin, P.C., Marsico, T.D., Thomas, K.A., Herms, D.A., and Mech, A.M. 2016. “Looking for black and white in the grey: Variation in invasion success and management challenges in a global community.” International Congress of Entomology (ICE), September 2016, Orlando, Florida. Conference talk.
- Overview
Although most introduced insects are relatively benign, some become high-impact pests causing widespread ecological and economic damage. Introduced insects that are specialists and feed on a single genus of plants can be high-impact as they can potentially eliminate an entire native plant genus over large areas. Luckily, most introduced insects with this feeding behavior do not become high-impact pests. However, there is great need to predict, prior to their introduction, which insects have the potential to result in high-impact invasions so risk assessment and management are informed.
A group of USGS, Forest Service, and university scientists are working together to study how ecology and evolution might be used to understand when introduced insects become high-impact. We are examining the contribution of five types of drivers toward these impacts: (1) the insects’ and host plants’ evolutionary history, (2) the hosts’ defenses or lack thereof (defense-free space), (3) presence of natural enemies or lack thereof (enemy release), (4) invader traits, and (5) geographic and temporal considerations.
A conceptual diagram of the drivers that may determine the impact of a specialist insect pest. We posit that the relationship between evolutionarily naïve host plants and invasive insect species is the strongest driver of a high-impact invasion. The diagram, modified from the synthetic invasion meta-framework described by Gurevitch et al. (2011), is guiding our USGS Powell working group’s data compilation and synthesis. Click on image to enlarge it. Background & Importance
Within their native range, where the insects and their host plants evolved together (coevolution), host plants develop effective defenses that limit insect feeding. Plants are often less resistant to introduced insects when a coevolutionary history with the insects is lacking; they are considered to be evolutionarily naïve. Many examples of invasions in North America that have caused wide-spread death of native plants, are introduced insects that specialize on feeding on a particular genus of plants that are evolutionarily naïve to that insect. In order words the plant lacks defenses to the insects feeding on them.
Introduced insects also may have the benefit of release from their natural enemies that are present in their native environment. Release of natural enemies is often provided as a reason for the ability of the introduced insect to persist and spread. However, release from natural enemies provides only a partial explanation for invasion success. A far less-studied mechanism is the defense-free space hypothesis that states it is insufficient defenses of the host plants that allow the invading insect to thrive. Researchers have demonstrated the importance of including the lack of coevolved defenses in establishing the risk of invasion, they have not sufficiently incorporated the role of coevolved plant defenses into explanations of impacts of invasion.
General Methods
The USGS Powell Center sponsors researchers to meet and work together on a problem. Our working group has been addressing this problem through telephone conferences in late 2015 and 2016 and our first in person work meeting in Fort Collins in July 2016. We plan to continue our work throughout 2017 and 2018 and have planned our second week long in person work meeting in August of 2017.
We are focusing on introduced insects in North America that feed on native plants. The project has three implementation components data compilation and synthesis, model development and validation, and model evaluation and application. The conceptual diagram of drivers of invasive insect impact (see image) will guide our initial selection of introduced species and their representative traits and factors. These traits and factors will serve as predictor variables incorporated into and tested in a statistical model predicting invasion impact. Lastly, we will apply the parameterized model to insects not yet established in the U.S. to develop a probability ranking of those insects likely to become significant threats if introduced.
References Cited
Gurevitch, J., Fox, G.A., Wardle, G.M., Inderjit, and Taub. D., 2011, Emergent insights from the synthesis of conceptual frameworks for biological invasions: Ecology Letters, v.,14, p. 407-418.
Recent Presentations
- Schulz, A.N., A.M. Mech, M.P. Ayres, K.J.K. Gandhi, N.P. Havill, D.A. Herms, A. Hoover, A.M. Liebhold, T.D. Marsico, K.F. Raffa, K.A. Thomas, P.C. Tobin, D.R. Uden, and R.A. Hufbauer. November 2020. Which factors drive impact of introduced insects feeding on North American conifers and woody angiosperms? The data speak. 68th Annual Meeting of the Entomological Society of America. Virtual Conference.
- Mech, A.M., K.A. Thomas, T.D. Marsico, D.A. Herms, C.R. Allen, M.P. Ayres, K.J.K. Gandhi, J. Gurevitch, N.P. Havill, R.A. Hufbauer, A.M. Liebhold, K.F. Raffa, A.N. Schulz, D.R. Uden, and P.C. Tobin. 2020. How available data can be used to predict the impact of non-native forest insects. Society of American Foresters National Convention. Virtual Conference. Conference talk.
- Thomas, K.A., A.M Mech, P.C. Tobin, D.A. Herms, M.P. Ayres, N.P. Havill, C.R. Allen, K.J.K. Gandhi, J. Gurevitch, A. Hoover, R.A. Hufbauer, A.M. Liebhold, K.F. Raffa, A.N. Schulz, D.R. Uden, and T.D. Marsico. 2020. Predicting the impact of non-native insects on forest trees: The data speak. North American Invasive Species Management Association (NAISMA). Virtual conference. Conference talk.
- Thomas, K.A., Mech, A.M., Ayers, M.P. Tobin, P.C., Herms, A., Havill, N.P., Uden, Da. Schulz, A. N., Allen, C.R., Gandhi, K.J.K. Gurevitch, J., Hoover, A., Hufbauer, R.A., Liebhold, A.M., Raffa, K.F., and Marsico, T. D. 2020. Predicting the impact of non-native insects: The data speak. Ecological Society of America, August 3-7, 2020. Virtual venue. IP 119465 2020/05/27
- Thomas, K.A. 2020. Predicting the impact of non-native tree-feeding insects on North American trees. USGS Southwest Biological Science Center Sweet Science. Seminar talk.
- Mech, A.M. Searching for the holy grail of invasions – What if we could predict the impact of non-native insects? 2018. 27th Annual Southern Appalachian Forest Entomologist/Pathologist Seminar. March 2018. Crossnore, NC. Seminar talk.
- Mech, A.M., Herms, D.A., Marsico, T.D., Thomas, K.A., and Tobin, P.C. 2018. “Predicting the impact of non-native specialist insects”. 29th USDA Interagency Research Forum on Invasive Species, January 2018, Annapolis, Maryland. Conference talk.
- Schulz, A.N., Mech, A.M., Allen, C.R., Ayres, M.P., Gandhi, K.J.K., Gurevitch, J., Havill, N.P. Herms, D.A., Hufbauer, R.A., Liebhold, A.M., Raffa, K.F., Raupp, M.J., Thomas, K.A., Tobin, P.C., and Marsico, T.D. 2018 “Assessment of Expert Perceptions of Non-Native Insect Impacts: Implications for Policy and Management”. Missouri Natural Resources Conference. January 2018. Osage Beach, Missouri. Conference poster.
- Mech, A.M., Herms, D.A., Marsico, T.D., Thomas, K.A. and Tobin, P.C. 2018. “Using evolutionary history to help identify high-impact non-native herbivorous specialist insects prior to their arrival.” Entomological Society of America (ESA), Entomological Society of Canada (ESC) and Entomological Society of British Columbia (ESBC) Joint Annual meeting. November 2018. Vancouver, British Columbia. Conference talk.
- Schulz, A.N., Mech, A.M., Allen, C.R., Ayres, M.P., Gandhi, K.J.K., Gurevitch, J., Havill, N.P. Herms, D.A., Hufbauer, R.A., Liebhold, A.M., Raffa, K.F., Raupp, M.J., Thomas, K.A., Tobin, P.C., and Marsico, T.D. 2018. “Do All Great Minds Think Alike? An Assessment of Expert Perspective on the Impacts of Non-Native Insects in North America”. Entomological Society of America (ESA), Entomological Society of Canada (ESC) and Entomological Society of British Columbia (ESBC) Joint Annual meeting. November 2018. Vancouver, British Columbia. Conference virtual poster.
- Thomas, K.A., Mech, A., Hoover, A., and Tobin, P., Allen, C., Ayers, M., Gandhi, K, Gurevitch, J., Havill, N., Herms, D., Hufbauer, R., Liebhold, A., Marsico, T., Raffa, K., Schulz, A. and Uden, D. 2018. “Traits and factors of non-native phytophagous insects in North America: The TRAFAC database”. Entomological Society of America (ESA), Entomological Society of Canada (ESC) and Entomological Society of British Columbia (ESBC) Joint Annual meeting. November 2018. Vancouver, British Columbia. Conference poster.
- Liebhold, A.M. Mech, A.M., Allen, C.R., Ayres, M.P., Gandhi, K.J.K., Gurevitch, J., Havill, N.P. Herms, D.A., Hufbauer, R.A., Raffa, K.F., Raupp, M.J., Schulz, A.N., Thomas, K.A., Tobin, P.C., and Marsico, T.D. et al. 2017. Predicting the Impact of Non-Native Specialist Insects Feeding on North American Host Plants, COST Action FP1401 - A global network of nurseries as early warning system against alien tree pests - Working Group and Management Committee Meeting, Offenburg, Germany. Conference talk.
- Mech, A., P.C. Tobin, T.D. Marsico, K.A. Thomas, D.A. Herms, C.R. Allen, M.P. Ayres, K.J.K. Gandhi, J. Gurevitch, N.P. Havill, A. Hoover, R.A. Hufbauer, A.M. Liebhold, K.F. Raffa, M.J. Raupp, A.N. Schulz, and D. Uden. August 2017. Predicting the next high-impact insect invasion. USGS John Wesley Powell Center for Analysis and Synthesis Seminar Series. Ft. Collins, CO. Seminar talk.
- Thomas, K.A., Mech, A., Herms, D.A., Marsico, T., and Tobin, P. 2017. “Establishing traits that may determine the impacts of introduced herbivorous insects on North American (NA) conifers” Pacific Branch Entomological Society of America Annual Meeting. April 2017. Portland, Oregon. Conference talk.
- Mech, A.M., Marsico, T.D., Thomas, K.A., Herms, D.A., and Tobin, P.C. 2017. “Predicting the Impact of Non-Native Specialist Insects Feeding on North American Host Plants” Ecological Society of America Annual Meeting. August 2017. Portland, Oregon. Conference talk.
- Tobin, P.C., Marsico, T.D., Thomas, K.A., Herms, D.A., and Mech, A.M. 2016. “Looking for black and white in the grey: Variation in invasion success and management challenges in a global community.” International Congress of Entomology (ICE), September 2016, Orlando, Florida. Conference talk.
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