Helen Hull-Sanders Assistant Professor Department of Biology 2001 Main St. Buffalo, NY 14208 Phone: (716) 888-2586 Fax: (716) 888-3157 Email: hullsanh@canisius.edu

Education

Ph.D. Entomology. Auburn University, Auburn, AL, 2004.
Dissertation Title: Influences of herbivores and inbreeding on the maintenance of a mixed mating system in the entire-leaf morning glory, Ipomoea hederacea (Advisor - Micky Eubnaks)

M.S. Biology. University of New Orleans, New Orleans, LA, 1999.
Thesis Title: Effects of leaf-cutter ants (Atta colombica Guerin) on understory structure in a Neotropical forest (Advisor - Jerome Howard)

B.S. Zoology. The University of Texas at Austin, Austin, TX, May, 1983.

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Research Program

Current Research: As an evolutionary ecologist I tend to focus on "why" questions. "Why are some exotic plants invasive while others are not?" "Why do some insects become specialists, feeding on only one or a few plants while other insects are generalist, feeding on multiple host plants?" "Why are some plants able to self-fertilize even though self-fertilization reduces fitness?" All these questions lead to "what" questions - especially "what chemicals are involved in plant defense?"

Evolution of Invasivenss: Invasive, exotic plants cost millions of dollars in agricultural loss and damages annually and are believed to be second only to habitat loss in terms of their impact on native diversity. However, the mechanisms that allow plants to become invasive are still poorly understood. It is frequently assumed that introduced plants leave their specialized herbivores and pathogens behind when they colonize new areas and this loss of regulation by natural enemies is thought to contribute to plants' potential for invasiveness. The Evolution of Increased Competitive Ability (EICA) hypothesis reasoned that if specialist herbivore pressure on exotic plants is reduced in the introduced range, then invasive plants should evolve to decrease their investment in chemical defenses and thus maximize their investment in growth and reproduction. I tested the responses of a specialist leaf-feeding beetle, Trirhabda virgata, and a generalist caterpillar, Spodoptera exigua, on native and invasive late golden-rod plants, Solidago gigantea. I found that specialist beetle growth is not affected by native or invasive host plants, but that generalist caterpillar growth was significantly greater on invasive plants. This suggests that invasive plants have reduced their investment in some herbivore defenses.

Evolution of Plant Mating Systems: When insect pollinators are limited in nature, plants are forced to self-pollinate or inbreed. Offspring produced by these incestuous matings typically results in broad, detrimental changes in plant morphology and physiology. Previous studies have found that generalist herbivores perform better when reared on inbred plants. I investigated if insect responses to inbred plants were universal by using current Plant Defense Theory. The Plant Stress Hypothesis predicts that generalist herbivores will perform better on inbred plants; whereas Plant Vigor Hypothesis predicts that specialist herbivores will perform better on outbred plants. I found that both specialist tortoise beetles and generalist armyworms performed better when reared on outbred plants, but that aphid density increased significantly faster on inbred plants. This study suggests that feeding strategy may influence herbivore performance rather than the number of potential host plants.

In addition, I investigated inbreeding depression and selfing rate in Ipomoea hederacea to determine if inbreeding depression contributed to the maintenance of the mixed mating system in Alabama populations. Inbreeding depression differed between populations and the magnitude varied at germination, growth (as measured by above ground biomass), and reproductive potential. Selfing rate ranged from ~4% to > 80% in twelve populations tested. The high selfing rates, high levels of homozygosity and low levels of inbreeding depression suggest that inbreeding depression is not the mechanism maintaining the mixed mating system in I. hederacea.

New Research: I will be working with Dr. John Losey at Cornell University investigating the non-target effects of corn that has been genetically-modified to contain genetic material from the soil-dwelling bacteria Bacillus thuringiensis (Bt). This transgenic "Bt corn" produces a toxin which protects it from pest attack. Dr. Losey was one of the first to notice that Bt corn pollen was potentially harzardous to monarch butterfly health. We are very interested to see if Bt corn that specifically targets leaf-feeding beetles will be harmful to non-target leaf-feeding beetles.

For more information on transgenic corn, visit http://www.extension.umn.edu/distribution/cropsystems/DC7055.html

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Teaching Program

BIO 102 Organismal Biology

Spring. 4 credits. Prerequisite: C- or better in BIO 101 or permission from the chair.

Introduction to principles governing biological processes at the organismal level in plants and animals. Structure-function relationships of organisms is stressed. Three hours of lecture and one one-hour recitation per week. Enrollment in laboratory component expected.

BIO 201 Evolution, Ecology and Population Biology

Fall. 4 credits. Prerequisites: BIO 101 and BIO 102

Intra- and inter-specific interactions between organisms, interactions between organisms and their environment, and mechanisms of evolutionary change and speciation. Three hours of lecture, one-hour of recitation and three-hours of laboratory per week.

BIO 332 Medical-Veterinary Entomology

Spring. 3 credits. Prerequisite: BIO 201

Students will recognize the major orders of insects and arthropods associated with disease; be able to discuss the difference between vectoring, transmitting and contracting disease caused by pathogens; and recognize the symptoms or manifestation of arthropod associated pathogens.

BIO 343 Entomology

Fall, alternate years. 4 credits. Prerequisites: BIO 201

Students will learn recognize the major orders of insects. Insect collections, field observations and specimen preservation will be focused on in the lab.

BIO 353 Senior Seminar

Spring. 1 credit. Prerequisite: Senior Standing

This is designed as a capstone course for graudating seniors. Students will attend at least 3 scientific seminars invited by the faculty. In addition, students will develop and present 2 seminars based on the current scientific literature.

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Publications

G.A. Meyer and H.M. Sanders Altered Patterns of Growth, Physiology and Reproduction in Invasive Genotypes of Solidago gigantea. (submitted, Biological Invasions)

Hull-Sanders, H.M., R. Clare, R.H. Johnson, and G.A. Meyer. Evaluation of the Evolution of Increased Competitive Ability (EICA) hypothesis: loss of defense against generalist but not specialist herbivores. (in press, Journal of Chemical Ecology).

Hull-Sanders, H.M., M.D. Eubanks and D.E. Carr. 2005. Inbreeding depression and selfing rate of Ipomoea hederacea var. integriuscula (Convolvulaceae). American Journal of Botany. 92:1871-1877.

Hull-Sanders, H.M. and M.D. Eubanks. 2005. Plant defense theory provides insight into interactions involving inbred plants and insect herbivores. Ecology. 86:897-904.

Hull-Sanders, H.M. and J.J. Howard. 2003. Impact of Atta colombica colonies on understory vegetation and light availability in a Neotropical forest. Biotropica. 35:441-445:

Hull-Sanders, H.M., A.G. Appel, and M.D. Eubanks. 2003. Comparative water relations of adult and juvenile tortoise beetles: Differences among sympatric species. (Coleoptera: Chrysomelidae: Cassidinae). Comparative Biochemistry and Physiology. 135:625-634.

Eubanks, M.D., S. Blackwell, C. Parrish, Z. Delamar, and H. Hull-Sanders. 2002. Pervasive and Intense Intraguild Predation by an Invasive Ant: The Effects of Red Imported Fire Ants on Beneficial Arthropods. Environmental Entomology. 31:1168-1174.

Hammond, I., D. Grossman, J. Jones, H. Hull-Sanders, P. Lundy, W. Steinmann. 1995. Appropriate Use of Abdominal Ultrasonography in Two Hospitals. American Journal of Managed Care. 1: 271-275.

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Lab Group

Students who work in my lab are expected to perform research. The first year, students work on projects that support some of my on-going research goals. The second year, students are expected to begin branching out and thinking about their own questions. I am a member of five scientific societies: Ecological Society of America, Entomological Society of America, the Society for the Study of Evolution, the Botanical Society of America, and the American Association for the Advancement of Science. I attend at least one meeting a year and will take students to meetings appropriate to the research they complete. In addition, everyone is expected to help maintain host plants and insect colonies that are used for both research and educational outreach. We currently have Madagascar hissing cockroaches (Gromphadorhina portentosa), Golden tortoise beetles (Charidotella bicolor) and Sawtooth grain beetles (Oryzaephilus surinamensis). We expect to have Corn flea beetles (Chaetocnema pulicaria) summer 2007.

Current students
Daniel Fahey
Ryan Lydon
Carl Manzo
Kelly Kaempf
Melanie Russ

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