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Home -> Department Directory -> Faculty -> George E. Heimpel -> Current People

Current members of the
Heimpel lab, and their projects

	George Heimpel Associate Professor 1997 – present. Ph.D. University of California, Davis 1995 Born in: Göttingen, Germany Grew up in: El Cerrito, California, USA
Research projects/interests: Research in our lab focuses on biological control and natural enemy ecology.  The main subjects of most projects are parasitoids, but predators and reproductive parasites are represented as well.  Current projects include: Soybean aphid biological control Sex determination in parasitoid wasps Conservation biological control using flowering and overwintering cover crops Life-history evolution in parasitoid wasps Natural enemies and resistance evolution in pests of transgenic crops Other interests: Ping Pong, Basketball, Birdwatching, Hiking, Guitar playing
	Jetske de Boer Ph.D. 2004 Wageningen University, The Netherlands (Thesis-title: Bugs in odour space! How predatory mites respond to variation in herbivore-induced plant volatiles). Advisors: Marcel Dicke & Maurice Sabelis. M.Sc. 1999 Wageningen University, The Netherlands (Plant breeding and crop protection) Hometown: Schoonhoven, The Netherlands (not far from the “famous” Gouda-cheese)
Research projects/interests: My research interests are in the ecology and behavior of parasitoid wasps. I am currently studying their mechanisms of sex determination and mating behavior. This is a fascinating topic because parasitoid wasps are haplodiploid, males normally being haploid and females diploid. This means that they cannot have true sex chromosomes. In the 1940’s Whiting showed that in the parasitoid Bracon hebetor sex is determined at a single highly polymorphic sex locus and not just by fertilization of the egg. Individuals that are heterozygous at this locus develop into diploid females, whereas homozygotes develop into diploid males. Unfertilized eggs are always hemizygous and develop into haploid males. This complementary sex determination (CSD) has since been found in more than 40 hymenopteran species, including honeybees, wasps, and ants. CSD is now thought to be the ancestral mode of sex determination in the Hymenoptera. Diploid males that are produced under CSD usually have low viability, are sterile or they may produce triploid daughters. They are produced instead of fertile diploid females so they represent a strong cost to a population, and potentially reduce the efficiency of biological control. The cost of CSD is especially high under inbreeding conditions because the frequency of diploid males is much higher under inbreeding than under random mating. My project aims to determine whether in a range of Cotesia species sex is determined by CSD or not. I will study both solitary and gregarious Cotesia species. We expect to find CSD in solitary but not in gregarious species because under natural conditions, the level of inbreeding is thought to be much higher in gregarious species. We therefore expect these species to have evolved away from CSD to another mechanism of sex determination in which diploid males are not formed. Another aspect of this project is comparing the mating behavior and mating system of solitary and gregarious Cotesia species. Besides studying sex determination at the population level, we are currently starting to investigate the molecular basis of CSD in parasitoid wasps. A single gene for CSD has been cloned in honeybees and we are using this recent development to search for homologous genes in parasitoid wasps. I am excited about studying sex determination in parasitoid wasps from the molecular basis all the way to population-level effects and behavior. Publications/presentations Other interests: Being outdoors! I love camping and almost any outdoors activities such as canoeing, biking, hiking, watching and photographing animals of any sort (see www.remjet.nl), and recently started exploring winter-activities because Minnesota has the right climate for that!
	Jeremy M. Chacon Ph.D. student 2005-present B.S. in Zoology, B.S. in Conservation Biology, UW – Madison 2003 Hometown: I grew up in the suburbs of Chicago
Research projects/interests: As a new student in the lab, I am just beginning to explore the possible directions my research can take over the next few years.  However, I do know that it will mostly focus on the biological control of the soybean aphid, Aphis glycines Maxx.  My current field project is studying the effects of Asymmetrical Intraguild Predation on soybean aphid populations.  Intraguild Predation (IGP) is when two or more species share a host/prey species, and also engage in a trophic interaction with each other.  Asymmetrical Intraguild Predation is a type of IGP in which only one of the species (the IG-Predator) feeds or parasitizes the other species (the IG-Prey), while both species share a single host/prey.   In this study, I am trying to determine if either (i) the natural enemies present in the field (the IG-Predators, such as Coccinellids), (ii) a released parasitoid wasp, Aphidius colemani (the IG-Prey), or (iii) both together are the most effective controllers of the soybean aphid. In the lab, I am working on sequencing the Internal Transcribed Spacer 1 (ITS-1) region of the 16S gene of multiple parasitoid wasps.  After finishing this, I will develop species-specific primers within that region for subsequent use in molecular gut-content analysis of predators collected from my field study.  My hope is that I will be able to determine the frequency with which certain predators will eat parasitized aphids, thus engaging in IGP.  The combination of this knowledge plus the knowledge gained from the field study will help give a better understanding of Asymmetrical IGP of soybean aphid biocontrol agents, and thus a better understanding of the most efficient way to control the soybean aphid. Publications/presentations: None yet, but I will be presenting a Ten-Minute Paper at this November’s ESA meeting in Florida. Other interests:  Outside of loving bugs, I also enjoy playing guitar, riding my longboard, cooking and eating, and playing with my cat, Luna.  You can listen to some songs I’ve written at http://www.myspace.com/jeremychacon if you so desire.
	Annie-Ève Gagnon M.S. Student 2004 – present (Université Laval & University of Minnesota) Co-advisors: J. Brodeur & G.E. Heimpel B.S. Université du Québec à Montréal – 2004
Research Projects/Interests: My research is focused on understanding the population dynamics of the predators of soybean aphid (SBA), Aphis glycines. Since its invasion of North America in 2000 the SBA has notably changed the arthropod community of the soybean agroecosystem. Several predators rapidly responded to the expanding range and increasing populations of SBA. The first objective of this study is to characterize the species composition of the foliar and ground predatory fauna associate with SBA. Surveys of beneficial organisms have been done to document their nature, abundance and potential role on the pest. This survey was done in seven fields in Québec, Canada. We used pitfall traps to estimate population levels of ground beetles and the foliar predators were collected with sweep nets and characterized with visual examination. Coccinellids are the most important aphidophagous predators found on the soybean crop in Canada. The second objective of this study is to determine the impact of intraguild predation between coccinellid species. Intraguild predation (IGP) is an antagonist interaction between natural enemies wherein one predator consumes another from the same guild. It may explain why natural enemy communities sometimes fail to reduce pest populations. To test the presence of IGP, we are using a PCR-based method to detect DNA of intraguild prey in the guts of coccinellid predators, using primers that amplify the ITS-1 or COI regions. Primers will be developed for five species of coccinellids: Harmonia axyridis, Hippodamia convergens, Coleomegilla maculata, Coccinella septempunctata and Propylea quatuordecimpunctata. We will use this method to analyze gut contents of field-collected individuals.  This study will give us a better understanding of the predator’s role of SBA regulation and the impact of IGP between coccinellid species.
	Karl Gruber Ph.D student, 2006-present (Ecology, Evolution and Behavior, U of MN) M.S. 2005 (Ecology, Evolution and Behavior, U of MN) Thesis presentation pdf B.S. Zoology, 2003, University of Panama Hometown: David, Chiriqui. Panama.
Research projects/interests During the last six years I have worked with many different organisms, but always focusing on the same topic: evolution. My main fields of interest are molecular systematics, phylogeography, and historical biography of neotropical taxa using DNA sequence data. Also I am interested in several topics of molecular evolution at the level of genes and genomes. I have been very fortunate in being able to work at great places and most importantly with great people since my years as a college senior. See my webpage for more details. For my PhD, I am studying the evolution of a gene related to sexual development in several species of insects.  A recent report by Beye et al. (2003) found evidence of the existence of a gene called csd (‘complementary sex determiner’) that plays an important role in the sex determination of honey bees and is likely to be involved in sex determination of many other hymenopteran species. The main objective of my PhD research is to identify the csd gene in members of the parasitoid families Ichneumonidae and Braconidae in order to follow the evolution of this gene within the superfamily Ichneumonoidea. The Ichneumonoidea is a large superfamily within the Hymenoptera that contains species that range widely in their mating systems and that also contains many species that are economically important from the standpoint of biological pest control.  The outcome of this research will provide important information regarding the evolution of the csd gene in the Hymenoptera as well as providing clues for the understanding of the evolution of mating systems in parasitoids.  It will also be of practical use in the improving our understanding of how parasitoids can be used as biological control agents. Publications/Presentations Other interests: Mostly cooking.
	Cynthia (Simon) Hsu Ph.D. Student 2001 – present M.S. Cornell University Entomology B.S. University of California, Davis, Soil and Water Science Hometown:  Rochester, NY
Research projects/interests: My research is focused on understanding the dispersal behavior of a parasitoid, Macrocentus grandii, in relation to the spatial patterns of its host, the European corn borer, Ostrinia nubilalis.  Current work includes a spatial pattern analysis of the distribution of corn borers and occurrence of parasitism by M. grandii.  Results from these experiments will be used to determine whether identifying density dependent parasitism for this parasitoid depends on the spatial scale of analysis, and whether the ability to identify density dependent parasitism improves using a spatially explicit analysis compared with a spatially implicit analysis. The second project focuses on measuring the short-range dispersal of M. grandii within a corn field that has two host densities.  In this experiment, 40-acre fields are split in half with one half of the field containing a low density of hosts while the other half has a high density of hosts.  A strip of corn between the two halves is labeled using rubidium chloride (RbCl).  Parasitoids emerging from this strip are labeled with RbCl and adult parasitoids are recaptured at different distances into the two halves.  Results from this experiment will be used to determine whether the dispersal behavior of the parasitoid depends on host density, and to estimate the dispersal-distance relationship for M. grandii over short distances (i.e. within 50 meters) for each of the two halves.  My final project makes use of the empirical data on parasitism and parasitoid dispersal to estimate the potential impact of M. grandii on the evolution of resistance in European corn borers to Bt corn. Research interests:  spatial distributions of insects, spatial population dynamics, insect dispersal, biological control, habitat and landscape manipulations to improve biological control, landscape ecology Publications/presentations Other interests: empowerment of women, increasing cultural awareness, community activism, hiking, gardening, theater, live music, cooking/baking, historic house restoration projects (plaster, brickwork, carpentry, etc.), potlucks and eating good food with good friends.
	Robert Koch Postdoctoral Researcher 2005-present Ph.D. Entomology, University of Minnesota, 2005 B.A. Biology, Saint John's University, 1999 Hometown: Monticello, Minnesota Visit my web page for my current CV
Research projects/interests: My research interests revolve around Integrated Pest Management, Invasive Species, and Risk Assessment.   I am currently a Postdoctoral Associate in George Heimpel's lab.   My research evaluates the use of a fall-seeded rye cover crop for suppression of an economically significant pest of soybeans, the soybean aphid ( Aphis glycines ).   Much of my previous work was focused on the biology and impacts of an invasive coccinellid, the multicolored Asian lady beetle (Harmonia axyridis).
	Chris Kulhanek Junior Scientist 2004-present B.S. University of Wisconsin-Eau Claire- 2003; Biology Hometown: Green Bay,Wisconsin (and no, I’m not a football fan!)
Research projects/interests: My research focuses on host specificity of several parasitoids and a predator of the soybean aphid collected in Asia and held within the MDA/UMN Quarantine Facility. Prior to the potential release of these control organisms, however, we are doing a risk assessment of the organism including studying the ability of the control organism to attack the target host vs. non-target hosts.  This screening process increases the chance for success of the biocontrol agent if it is found to be a candidate for release.  Another part of my research involves using genetic techniques to reliably differentiate between different parasitoid species.  I am also interested in educating the general public about the wonder of all things natural, especially insects, as through education tolerance may be increased. Other interests:  I enjoy social dancing of all sorts especially swing (www.tcswing.com), salsa and ballroom and also enjoy bike riding and most any outdoor activity.
	Kris A.G. Wyckhuys Postdoctoral Researcher 2005 – present PhD 2005 Purdue University (Thesis title: Social and ecological factors influencing the adoption of integrated pest management technologies in Honduran small-scale agriculture) MSc 2000 Ghent University, Belgium (Agricultural Engineering, Crop Protection) Hometown: Tielt, Belgium
Research projects/interests: My research is built around the theme of soybean aphid biological control and is primarily executed at the MAES/MDA High Security Containment Facility. Baseline research conducted at this facility could help pave the road for the introduction of natural enemies against the pest that currently affects one of the US key agricultural commodities. Feeding directly into this larger project, my research intends to (1) examine the efficacy of candidate parasitoids in suppressing soybean aphid outbreaks and (2) screen for potential negative side-effects of the use of non-native organisms on the local ecosystem. More specifically, I’m screening host specificity of the various exotic parasitoids currently held at the quarantine facility. A host range assessment will be conducted in which candidate parasitoids are confronted with different potential aphid hosts in a choice/no-choice situation or within an environment where additional food resources (i.e honey) are either present or lacking. Next, for aphid species which potentially are at risk of parasitism by introduced agents, phenology and population dynamics are determined on their respective host plants found within local habitats (i.e. prairie grasslands). Some of the conditions under which native aphids are found in the field (i.e. ant tending, behavioral specificities that protect from parasitism) are mimicked in the quarantine facility and readily incorporated in pre-release impact assessments. Lastly, for some of the candidate parasitoids, information is gathered on the semio-chemical cues that elicit their habitat location, host searching and host acceptance behavior. Such information could ultimately be employed in a more accurate prediction of the likelihood of released parasitoids attacking native aphids in the habitats in which they naturally occur. My long-term interests embrace both ecological and social facets of the design and promotion of IPM and/or biological control in (inter-)national agricultural production systems. Balancing between soft and hard sciences, I aspire to pursue a more holistic approach in seeking an answer to questions of agricultural sustainability, rural development and technological change. My research interests hereby include -but are not limited to- invasion biology, landscape ecology, rural sociology, ethno-entomology and traditional pest management. Kris Wyckhuys CV