BIOLOGICAL INVASIONS AND BIOLOGICAL CONTROL

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 0229555
• Project Start Date: Jul 1, 2012
• Project End Date: Jun 30, 2017
• Program Code: [(N/A)]- (N/A)

Recipient Organization
COLORADO STATE UNIVERSITY
(N/A)
FORT COLLINS,CO 80523

Performing Department
Agricultural Biology

Non Technical Summary
We are studying the roles of ecology and genetics in the founding new populations, which is relevant to biological invasions, conservation, and biological control.

Animal Health Component

20%

Research Effort Categories

Basic

80%

Applied

20%

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
136	0799	1070	20%
136	0899	1080	20%
136	0799	1080	20%
213	0799	1070	20%
213	0799	1080	20%

Knowledge Area
136 - Conservation of Biological Diversity; 213 - Weeds Affecting Plants;

Subject Of Investigation
0799 - Rangelands and grasslands, general; 0899 - Wildlife and natural fisheries, general/other;

Field Of Science
1070 - Ecology; 1080 - Genetics;

Keywords

invasion

weed

biological control

ecological genetics

adaptive evolution

common garden

population founding

inbreeding

propagule size

Goals / Objectives
Objective 1. The number of individuals founding a new population, and their genetic composition, largely determine whether the population will successfully establish or will go extinct. Remarkably little information exists on the relative importance of population size and genetics in the founding of new populations. My colleagues and I will evaluate the roles of demography (with a focus on numbers of individuals and demographic stochasticity) and genetics in the colonization process, from population founding through to subsequent growth, and further spread. Colonization success generally increases with the number of individuals in the founding and greater genetic diversity, but because the two are confounded (more individuals typically harbor greater genetic diversity) and because the relevant experiments manipulating both demography and genetics are difficult to do, their relative importance and potential interactions between them remain unknown. Objective 2. Biological invasions are arguably one of the most significant global environmental issues facing the modern world. Adaptive evolution has proven a key driver of invader success, however, the mechanisms driving the evolution of invasiveness in introduced species continue to be debated. The literature suggests that interactions with higher trophic levels (natural enemies) play a vital role. The proposed research synthesizes two foundational theories of plant-insect interactions in the context of biological invasion: optimal defense theory and the evolutionary dilemma model. Optimal defense theory predicts that plants will deploy defenses against herbivory in relationship to: 1) the fitness value of different tissues, and 2) the probability of attack in absence of defenses. However, this theory traditionally has been applied only to secondary chemicals and insects deterred by them - typically generalists. It largely ignores that both different types of defenses and different types of herbivores vary in ecological function. Specialists not only are better at detoxifying or sequestering secondary chemicals, but also often cue into them as feeding stimulants. Thus, plants are presented with an "evolutionary dilemma": lower investment in chemical defenses increases risk of attack by generalists, while higher investment in those same defenses increases risk of attack by specialists. Despite clear support of both optimal defense theory and the evolutionary dilemma model, to date these ideas have not been synthesized.

Project Methods
Objective 1. Members of my lab group and I will create inbred, standard, and outbred lines using three populations of Tribolium castaneum. The three source populations essentially serve as a type of replicate, as the consequences of inbreeding and outbreeding can vary among populations and families. We will make 3 independent lineages of each of the three line-types (inbred, standard and outbred) as described below (9 stock cultures). These independent lineages will enable us to capture some of the variation that is likely to exist in response to inbreeding and outbreeding (Pray & Goodnight 1995). We will maintain each of these 9 stock cultures throughout the experiment described below in standard 95% wheat flour 5% yeast medium. Using a system of boxes set up in arrays with the novel medium (corn based rather than wheat based), we will release the inbred, standard, and outbred lines at three different densities in a factorial experiment to test the relative importance of and interactions between demographic and genetic effects in the founding, initial growth, and spread of populations. The number of founding individuals used will be 2, 4, 12, and 32. Individuals will be gathered as pupae to ensure that they are virgins. We will allow the sex ratio to vary randomly, as uneven sex ratio is an important part of demographic stochasticity. (Thus, if we controlled the sex ratio, we would likely underestimate the strength of demographic processes, acknowledging that at this level, demographic stochasticity has an explicitly genetic basis.) We will evaluate rates of spread by allowing dispersal. We will continue to record population growth rates generation to generation, and also rate of spread through the experimental array. The experiment will be run for 12 generations (approximately 15 months). Variation in microsatellite loci will be measured on populations in arrays. Analyses will be done in conjunction with my colleague Brett Melbourne, at University of Colorado, Boulder. Objective 2. We will grow plants in a field common garden outside of Fort Collins, CO using seeds from sources across the native and introduced ranges. We have seed from 75 sites (25 native and 50 introduced). Replication for this experiment will focus on the site within range, with 3 maternal seed sources used per site. Replicate full- to half-siblings will enable us to destructively sample young and old leaves from plants at different developmental stages. We will measure the concentration of IGs and verbascoside (a mobile phenolic compound also occurring in V. thapsus [Georgiev et al. 2011]), trichome length and density, and use shearing techniques to quantify leaf toughness (Choong 1996). From these data, we will evaluate whether the patterns observed in the field are maintained when plants are grown in a common environment. We will also estimate lifetime reproductive success, providing us with phenotypic correlations between defense and fitness.

Progress 07/01/12 to 06/30/17

Outputs
Target Audience:Our target audience is scientists who work on biological invasions, biological control and founder effects, as well as land managers and those engaged in conservation and restoration of declining species. We reached these groups through a number of talks, as well as publications. My lab group, collaborators and I spoke at the Ecological Society of America, the International Congress of Entomology, the CSU Graduate Student Showcase and Front Range Student Ecology Symposium, the Guild of Rocky Mountain Ecologists and Evolutionary Biologists, and Washington State University. Thus we reached many scientists, from undergraduates to faculty, as well as land managers and the public. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Three graduate students and three postdoctoral scholars have contributed to this work. Furthermore, 6 undergraduates have contributed to the point of being included in publications, while many others have also been involved, and been trained and mentored as developing scientists. How have the results been disseminated to communities of interest?29 publications have come out from this work, and multiple talks and demonstrations have been given, including talks by graduate students and undergraduates, postdoctoral scholars, and the PI (Hufbauer). Two public outreach talks were given. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Many environmental issues of concern revolve around small populations. Introduced species that can become harmful invaders start as a few individuals in a small founder population; in biological management of pests (biological control) using predators and pathodens, the control agnets also start out as small founder populations; with habitat loss and change populations of desirable species can decline down to very few individuals. Thus, it is imperative to understand the processes that lead small populations to expand and grow or to dwindle to extinction. Here, a model species is used - Tribolium flour beetles grown in a laboratory setting - to address these issues. In general, we find that the genetics of the indiivduals in a small population can drive either expansion or extinction, and often are more important than the number of individuals. This finding, and the different contexts that increase the importance of genetics relative to numbers of individuals, is crucial to sound long-term management of both pest species and beneficial species. The specific accomplishments include results from a set of seven experiments using Tribolium beetles, 5 of which have been published to date. We have shown that genetic favors override demographic factors across many different contexts, and are crucial in both preventing invasion and conducting sound biological control, conservation, and restoration.

Publications

• Type: Journal Articles Status: Published Year Published: 2017 Citation: Szucs, M, BA Melbourne, T Tuff, C Weiss-Lehman , RA Hufbauer. 2017. Genetic and demographic founder effects have long-term fitness consequences for colonizing populations. Ecology Letters. 8:14303 DOI: 10.1038/ncomms14303
• Type: Journal Articles Status: Published Year Published: 2017 Citation: Stewart, GS, MR Morris, AB Genis, M Szucs, BA Melbourne, SJ Tavener, RA Hufbauer. 2017. The power of evolutionary rescue is constrained by genetic load. Evolutionary Applications. 10:731-741 DOI: 10.1111/eva.12489
• Type: Journal Articles Status: Published Year Published: 2017 Citation: Bitume, EV, D Bean, AR Stahlke, RA Hufbauer. 2017. Hybridization affects life-history traits and host specificity in Diorhabda spp. Biological Control 111:45-52. DOI: 10.1016/j.biocontrol.2017.05.009
• Type: Journal Articles Status: Published Year Published: 2017 Citation: Rogalski, M, C Gowler, C Shaw, RA Hufbauer, M Duffy. 2017. Human drivers of ecological and evolutionary dynamics in emerging and disappearing infectious disease systems. Philosophical Transactions of the Royal Society B. 372: 20160043
• Type: Journal Articles Status: Published Year Published: 2017 Citation: Hufbauer, RA. 2017. In focus: Admixture is a driver rather than a passenger in experimental invasions. Journal of Animal Ecology. doi: 10.1111/1365-2656.12600

Progress 10/01/15 to 09/30/16

Outputs
Target Audience:Our target audience is scientists who work on biological invasions, biological control and founder effects, as well as land managers and those engaged in conservation and restoration of declining species. We reached these groups through a number of talks, as well as publications. My lab group, collaborators and I spoke at the Ecological Society of America, the International Congress of Entomology, the CSU Graduate Student Showcase and Front Range Student Ecology Symposium, the Guild of Rocky Mountain Ecologists and Evolutionary Biologists, and Washington State University. Thus we reached many scientists, from undergraduates to faculty, as well as land managers and the public. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?These projects have provided training of a postdoctoral researcher through her promotion to research scientists, two additional postdoctoral fellows, three graduate students, and many undergraduates. Training consisted of laboratory and field research, data entry, data analyses, and writing. Professional development has included workshops on teaching effective classes, and on writing and publishing manuscripts. Additionally, all individuals have given formal presentations of their work at national and local conferences. How have the results been disseminated to communities of interest?In addition to the publications, several talks to professional audiences have been presented, and one to the general public (Catts Public Lecture Series, Washington State University). What do you plan to do during the next reporting period to accomplish the goals?My main goals for the comping period are to continue to help students write and publish papers. I'm initiating new research while on sabbatical on the pest species Drosophila suzukii, and am writing an NSF pre-proposal to work towards funding additional research.

Impacts
What was accomplished under these goals? Objective 1. I co-authored a review of the genetic consequences, and potential paradoxes, involved in biological invasions, as well as a paper on the world-wide invasion pathways of the fruit pest Drosophila suzukii. We have two papers on the dynamics of small populations, and the consequences of demographic changes and genetic changes for avoiding extinction and subsequent adaptation and population growth and spread accepted for publication in high impact journals (Nature Communications and Ecology Letters. As I'm on sabbatical, I did not initiate other large experiments, but am working with my students and postdocs from afar to get publications written up. Objective 2. A PhD student working on black henbane graduated, and a manuscript from her dissertation is in press. Work on tamarisk and tansy ragword biological control agents is progressing. Hybridization of the agents has contrasting effects in the two systems. In one, it appears to have no effect on life history, and in the other in produces agents with higher fitness.

Publications

• Type: Journal Articles Status: Published Year Published: 2016 Citation: Estoup, A, V Ravign�, RA Hufbauer, R Vitalis, M Gautier, B Facon. 2016. Is there a genetic paradox of biological invasions? Annual Review of Ecology, Evolution and Systematics. 47:51-72.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Lucy, FE, H Roy, A Simpson, JT Carlton, JM Hanson, K Magellan, ML Campbell, MJ Costello, S Pagad, CL Hewitt, J McDonald, P Cassey, SM Thomaz, S Katsanevakis, A Zenetos, E Tricarico, A Boggero, QJ Groom, T Adriaens, S Vanderhoeven, ME Torchin, RA Hufbauer, P Fuller, MR Carman, DB Conn, JRS. Vitule, J Canning-Clode, BS Galil, H Ojaveer, SA Bailey, TW Therriault, RClaudi, A Gazda, JTA Dick, J Caffrey, A Witt, M Kenis, M Lehtiniemi, H Helmisaari, VE Panov 2016. INVASIVESNET towards an International Association for Open Knowledge on Invasive Alien Species. Management of Biological Invasions 7:131-139 doi: 10.3391/mbi.2016.7.2.01
• Type: Journal Articles Status: Accepted Year Published: 2017 Citation: Fettig*, CE, RA Hufbauer. In press. Reproductive strategy, performance and population dynamics of the introduced weed black henbane (Hyoscyamus niger). Weed Science.
• Type: Journal Articles Status: Accepted Year Published: 2017 Citation: Weiss-Lehman , C, RA Hufbauer, BA Melbourne. In press. Rapid trait evolution drives increased speed and variance in experimental range expansions. Nature Communications.
• Type: Journal Articles Status: Accepted Year Published: 2017 Citation: Fraimout, A, V Debat, S Fellous, RA Hufbauer, J Foucaud, P Pudlo, M-M Marin, DK Price, J Cattel, X Chen, M Depr�, PF Duyck, C Guedot, G Loeb, M Kenis, MT Kimura, I Martinez-Sa�udo, M Pascual, MP Richmond, P Shearer, N Singh, K Tamura, A Xu�reb, J Zhang, A Loiseau, A Estoup. In press. Deciphering the routes of invasion of Drosophila suzukii by means of ABC random forest. Molecular Biology and Evolution.
• Type: Journal Articles Status: Accepted Year Published: 2017 Citation: Sz?cs*, M, BA Melbourne, T Tuff, C Weiss-Lehman, RA Hufbauer. In press. Genetic and demographic founder effects have long-term fitness consequences for colonizing populations. Ecology Letters.

Progress 10/01/14 to 09/30/15

Outputs
Target Audience:Our target audience is scientists who work on biological invasions, biological control and founder effects, as well as land managers and those engaged in conservation and restoration of declining species. We reached these groups through a number of talks, as well as publications. My lab group, collaborators and I spoke at the Ecological Society of America (8 presentations), the Entomological Society of America (1 presentation), the CSU Graduate Student Showcase (2 presentations), the International Converence on the Ecology and Management of Alient Plant Invasions (1 presentation) and the CSU Undergraguate Research and Creativity Showcase (1 presentation). Thus we reached many scientists, from undergraduates to faculty, as well as land managers. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?These projects have provided training of a postdoctoral researcher through her promotion to research scientists, two additional postdoctoral fellows, three graduate students, and many undergraduates. Training consisted of laboratory and field research, data entry, data analyses, and writing. Professional development has included workshops on teaching effective classes, and on writing and publishing manuscripts. Additionally, all individuals have given formal presentations of their work at national and local conferences. How have the results been disseminated to communities of interest?In addition to the publications, several talks to professional audiences have been presented. For example, Hufbauer spoke at the University of Wyoming, and to a group of INRA (French USDA) scientists, and the Cary Institute for Ecosystem Studies. What do you plan to do during the next reporting period to accomplish the goals?Our main goals for the next reporting period are to write and publish our results, to apply for additional funding, and to increase outreach to public groups for whom our findings are particularly relevant.

Impacts
What was accomplished under these goals? Objective 1. We published two papers on the dynamics of small populations, and the consequences of demographic changes and genetic changes for avoiding extinction and subsequent adaptation and population growth. We completed two experiments focused on what has been called "evolutionary rescue," which is essentially adaptation from standing genetic variation that enables a population to persist rather than go extinct. One of these focuses on small, closed populations that cannot disperse. We find, excitingly, that adaptation dramatically reduces extinction rates of populations in poor environments. In richer environments, extinction is uncommon with or without evolution, but evolving populations reach higher population sizes and have higher growth rates. However, eventually, inbreeding depression kicks in and evolving populations decline. We have a manuscript drafted, and in collaboration with mathematicians at CSU, are finalizing some mathematical models to estimate the number of generations it takes for inbreeding depression to overcome adaptation in evolving populations. In the other experiment we focused on the role of evolution in adaptation and invasion of a novel habitat. Evolving populations adapt to the novel environment and then grow to larger size and spread more quickly. It appears that faster spread is a consequence of higher population size rather than being driven by adaptation for faster spread. We are just starting analyses, and hope to submit a paper on this exciting work in 2016. In a third experiment, we study propagule pressure, the only consistent predictor of invasion success. We break down propagule pressure into components not typically studied - in addition to numbers of individuals and their genetic diversity, we evaluate the timing and duration of introduction events. We find that timing matters, with experimental invasions that occur early and late less successful than those that include middle time periods. Similarly, we are just starting analyses and hope to submit a paper on this in 2016. A fourth experiment was started using Bromus tectorum rather than Tribolium castaneum as a model system. This study focuses on the relative importance of local adaptation and genetic diversity in biological invasions. This experiment is in the field now, and the data will be collected summer 2016. I have also initiated a new project under this objective, with a collaboration with an NSF postdoctoral research fellow who is being mentored jointly by me and Dr. John McKay. She is studying the genetics of biological invasions, focusing on ancient DNA samples of an invasive weed available through herbaria. Objective 2. We continued progress on several manuscripts on Verbascum thapsus - one is very close to submission and two others are in progress. A PhD student working on black henbane defended, and the manuscripts from her dissertation should be submitted for publication soon. I have initiated two new projects under this objective, both focused on the consequence of hybridization among biological control agents for the safety and success of biological control. One focuses on tamarisk and its biological control agents, and is supported by a USDA postdoctoral fellowship, and the other focuses on tansy ragwort and it's biological control agents, and is supported by a USDA NIFA grant.

Publications

• Type: Journal Articles Status: Published Year Published: 2015 Citation: Migeon, A, P Auger, R Hufbauer, M Navajas. 2015. Genetic traits leading to invasion: plasticity in cold hardiness explains current distribution of an invasive agricultural pest, Tetranychus evansi (Acari: Tetranychidae). Biological invasions. DOI 10.1007/s10530-015-0873-8
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Barney, JN, DR Tekiel1, MN Barrios-Garcia, RD Dimarco, RA Hufbauer, P Leipzig-Scott*, MA Nu�ez, A Pauchard, P Pyaek, M V�tkov�, BD Maxwell. 2015. Global Invader Impact Network (GIIN): towards standardized evaluation of the ecological impacts of invasive plants. Ecology and Evolution. 5:2878-2889.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Tayeh, A, RA Hufbauer, A Estoup, V Ravign�, L�a Frachon, B Facon. 2015. Biological invasion and biological control select for different life histories. Nature Communications. 6:7268
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Hufbauer, RA, M Sz?cs*, E Kasyon�, C Youngberg�, M Koontz*, C Richards, T Tuff , BA Melbourne. 2015. Three dimensions of rescue can avert extinction in a changing environment. PNAS 112: 1055710562.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Hufbauer, RA, M Sz?cs*, E Kasyon�, C Youngberg�, M Koontz*, C Richards, T Tuff , BA Melbourne. 2015. Reply to Wootton and Pfister: The search for general context should include synthesis with laboratory model systems. PNAS www.pnas.org/cgi/doi/10.1073/pnas.1517210112

Progress 10/01/13 to 09/30/14

Outputs
Target Audience: Our target audience is scientists who work on biological invasions, biological control and founder effects, as well as land managers and those engaged in conservation and restoration of declinging species. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? This project has provided training of a postdoctoral researcher through her promotion to research scientist, three graduate students, and many undergraduates. Training consisted of laboratory and field research, data entry, data analyses, and writing. Professional development has included workshops on teaching effective classes, and on writing and publishing manuscripts. Additionally, all individuals have given formal presentations of their work at national and local conferences. How have the results been disseminated to communities of interest? In addition to the publications, several talks to professional audiences have been presented. For example, Hufbauer spoke at the University of Toronto, and Denver University. What do you plan to do during the next reporting period to accomplish the goals? Our main goals for the next reporting period are to write and publish our results, as well as find public groups who would be interested in hearing about the research findings.

Impacts
What was accomplished under these goals? Objective 1. We published a paper reporting on the important role of genetics for founding of populations even within the first generation. That is in the Proceedings of the Royal Society of London Series B. Objective 2. We published on defenses in our model invasive plant, and started analyzing data from the common garden run last year.

Publications

• Type: Journal Articles Status: Published Year Published: 2014 Citation: Fettig* CE, RA Hufbauer. 2014. Introduced N. American black henbane (Hyoscyamus niger) popluations are biennial. Invasive Plant Science and Management DOI: 10.1614/IPSM-D-14-00015.1
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Colautti, RI, SJ Franks, RA Hufbauer, PM Kotanen, M Torchin, JE Byers, P Pysek, O Bossdorf. 2014. The Global Garlic Mustard Field Survey: challenges and opportunities of a unique, large-scale collaboration for invasion biology. Neobiota 21:29-47
• Type: Journal Articles Status: Published Year Published: 2014 Citation: . Alba* C, MD Bowers, D Blumenthal, RA Hufbauer. 2014. Chemical and mechanical defenses vary among maternal lines and leaf ages in Verbascum thapsus L. (Scrophulariaceae) and reduce palatability to a generalist insect. Plos One 9 (8): e104889.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Turner , KG, RA Hufbauer, LH Rieseberg. 2014. Rapid evolution of an invasive weed. New Phytologist 202:309-321.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Sz?cs* M, B Melbourne, T Tuff , RA Hufbauer. 2014. The roles of demography and genetics in the early stages of colonization. Proceedings of the Royal Society B 281: 20141073.

Progress 01/01/13 to 09/30/13

Outputs
Target Audience: Our target audience is scientists who work on biological invasions, biological control and founder effects, as well as land managers and those engaged in conservation and restoration of declinging species. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? This project has provided training of a postdoctoral researcher, three graduate students, and many undergraduates. Training consisted of laboratory and field research, data entry, data analyses, and writing. Professional development has included workshops on teaching effective classes, and on writing and publishing manuscripts. How have the results been disseminated to communities of interest? In addition to the publications, several talks to professional audiences have been presented. For example, Hufbauer spoke at the University of Arkansas to the Entomology department there about what the research means for biological control of plant pests. What do you plan to do during the next reporting period to accomplish the goals? Our main goals for the next reporting period are to write and publish our results, as well as give talks to several outreach groups to disseminate our findings more widely.

Impacts
What was accomplished under these goals? Objective 1. We have run several experiments on the roles of founder population size and their genetic composition using the Tribolium system as well as the Bemisia system. Ongoing experiments further parse out the role of timing of founding population size in founder success. Objective 2. A large common garden experiment using populations from the native and introduced ranges of Verbascum thapsus. Parallel experiments were set up in the US (CO) and in the Czech Republic. Two treatments, a control (water) and a pesticide (reduced herbivory) were used to evaluate the effects of herbivory on the plants in both ranges.

Publications

• Type: Journal Articles Status: Published Year Published: 2013 Citation: Wilbur, HD, C Alba, AP Norton, RA Hufbauer. The effects of insect herbivory on the growth and fitness of introduced Verbascum thapsus L. Neobiota 19:21-44.
• Type: Journal Articles Status: Published Year Published: 2013 Citation: Kumschick S, RA Hufbauer C *Alba, DM Blumenthal. 2013. Evolution of fast-growing and more resistant phenotypes in introduced common mullein (Verbascum thapsus). Journal of Ecology 101:378-387
• Type: Journal Articles Status: Published Year Published: 2013 Citation: Hufbauer, RA, A Rutschmann, B Serrate, H Vermeil De Conchard, B Facon. 2013. Role of propagule pressure in colonization success: disentangling the relative importance of demographic, genetic and habitat effects. Journal of Evolutionary Biology. doi: 10.1111/jeb.12167

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

Outputs
OUTPUTS: Biological invasions are arguably one of the most significant global environmental issues facing the modern world. Adaptive evolution has proven a key driver of invader success, however, the mechanisms driving the evolution of invasiveness in introduced species continue to be debated. The literature suggests that interactions with higher trophic levels (natural enemies) play a vital role. For this annual report, I will focus on some of the key results from the Verbascum thapsus system. We evaluated plant performance and interactions with enemies from field sites in both the native and introduced ranges. Invasive populations are bigger, individuals are larger, and herbivory is lower, particularly on the young leaves that are important in future plant growth. These differences are reflected in defenses against generalist herbivores, which are rare in the native range but dominate the herbivore community in the introduced range. Namely, in the introduced range, defenses are dramatically higher in young leaves than they are in the native range. Common garden experiments show that the size differences are at least partially genetically based, and thus defenses may be, too. These results are disseminated in two publications, and have been presented at several international conferences. To aid managers, we studied one of the main means of controlling Verbascum: cutting off the inflorescence, or digging out the plant at its base. We found that Verbascum seeds can ripen even when inflorescences are cut from the plant, unless they are cut very early in the season. This result has also been published in a management journal, including specific recommendations to managers. PARTICIPANTS: Three students have been trained on this project: Hannah Wilbur, Christina Alba, Stacy Biddlecomb TARGET AUDIENCES: Academic scientists and land managers are our main target audiences. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
This research has trained two PhD students, one masters student and one postdoc. We have recommended to managers that if they are going to manage Verbascum using the common approach of cutting the inflorescence, that it is important for them to remove the material from the site and dispose of it properly.

Publications

• Alba C, MD Bowers, RA Hufbauer. 2012. Combining optimal defense theory and the evolutionary dilemma model to refine predictions regarding plant invasion. Ecology 93:1912-1921.
• Alba C, RA Hufbauer. 2012. A biogeographic comparison of Verbascum thapsus ecology reveals differences in performance, herbivory, and surrounding plant community. Biological Invasions. 14:2505-2518.
• Wilbur, HD, RA Hufbauer. 2012 Timing control efforts to limit seedset of common mullein (Verbascum thapsus). Invasive Plant Science and Management. 5:390-394
• Roderick GK, RA Hufbauer and M Navajas. 2012. Evolution and biological control. Evolutionary Applications. 5:410-423 Fauvergue, X, E Vercken, T. Malausa, RA Hufbauer. 2012. The biology of small introduced populations, with special reference to biological control. Evolutionary Applications 5:424-443.