Entomology

Goggy Davidowitz is a Professor and University Distinguished Scholar in the Department of Entomology with a joint appointment in the Department of Ecology and Evolutionary Biology. He has two main research projects. The first focuses on how insects adjust their growth and development to environmental change. More specifically, his lab studies how insects allocate the resources they acquire and how the allocation of nutrients among different traits affects their reproductive output. His research studies insects in both the field and laboratory. They are able to label specific nutrients such as carbohydrates, amino acids or fatty acids, with stable carbon isotopes to track how the insects use nutrients, second by second. A second line of research is developing insects as a source of protein for food and feed. Insects are more nutritious and more environmentally sustainable than vertebrate livestock. He has developed new technologies, and applied for patents, on how to use food and agricultural waste to feed insects to produce protein. His group is developing processes for insect farming so that farmers or entrepreneurs worldwide can develop their own insect farms to feed their local communities. Dr. Davidowitz founded a startup company, HexaFeast, to commercialize these processes and technologies.

Diana Wheeler, PhD, and her research interests are dominated by the physiological basis of caste differences in social insects, especially ants. Why ants? She is especially interested in the relevance of physiology to both social organization and evolution of insect sociality. Research has included included regulation of oogenesis, storage of proteins by adult workers and queens, mechanisms of sperm storage by queens, and, of course, caste determination.Dr. Wheeler is working on the molecular basis of caste determination in honey bees. Since caste is determined by the diet larvae receive, caste determination involves signaling pathways that are fundamental to pathways regulated by nutrition in all organisms, even single-celled ones. Insulin and TOR signaling pathways are turning out to be especially important. Her team also works to understand how pathways are shaped by natural selection acting at the level of the colony, in addition to the level of the individual.

Bruce Tabashnik, PhD, is the department head of Entomology at the University of Arizona. His research team studies the evolution and management of insect resistance to insecticides and transgenic plants. Current work focuses on evolution of resistance to insecticidal proteins from the bacterium Bacillus thuringiensis (Bt). Widespread use of transgenic corn and cotton that produce Bt toxins has increased the chances that pests will evolve resistance. Since 1997, Bt cotton has accounted for more than half of Arizona's 300,000 acres of cotton, which provides exceptional opportunities for field and laboratory research. Specific projects now underway include analyses of the genetics and ecology of pink bollworm resistance to Bt cotton, impact of Bt cotton on non-target insects, and effects of pollen-mediated gene flow from Bt crops to non-Bt crops. Progress is facilitated by synergistic collaborations that benefit from expertise in molecular and population genetics, ecology, modeling, and pest management.

Dr. Schlenke's research program uses fruit flies in the genus Drosophila to understand the evolutionary genetics of host-parasite interactions. For example, his lab has developed several species of parasitic wasps, which are readily observed infecting Drosophila in nature and can be very specialized to particular host species, as model parasites. These wasps lay single eggs in Drosophila larvae and, once hatched, consume flies from the inside out. Flies mount cellular and behavioral defense responses against wasps, but wasps have adaptations for finding host fly larvae, suppressing host cellular immunity, and manipulating host behavior. The Schlenke lab uses a variety of "omics" tools to understand the molecular genetics of fly cellular immunity and wasp virulence, as well as patterns of host immunity and pathogen virulence coevolution across fly and wasp phylogenies. The Schlenke lab also studies the genetics and neurobiology of behaviors that flies use to avoid being infected by the wasps and to cure themselves once they are infected, including various self-medication behaviors.

Our lab is interested in unraveling the genetics of aging and immunity in mosquitoes. By understanding these processes we can develop new strategies for controlling mosquito borne diseases. One of the greatest challenges mosquito borne parasites face within the vector is the mosquito's limited lifespan. For example, An. gambiae mosquitoes, the primary vector of malaria in sub-Sahara Africa, typically survive only two to three weeks in the wild. Since any parasites still within the mosquito when it perishes die as well, it is in the parasite's best interest to move on to the next vertebrate host as quickly as possible. Surprisingly, many mosquito borne diseases require up to two weeks of development in the mosquito before they can be passed back to the vertebrate host. This obligate incubation period within the mosquito provides an ideal target for controlling a range of insect borne diseases. Similarly, the mosquito immune system mounts a robust response against many pathogens, but not all. Expanding our understanding of mosquito immunity may allow us to manipulate mosquito immunity and limit their ability to transmit the most dangerous human pathogens. Both aging and immunity are regulated in part by the insulin/insulin grown factor 1 signaling (IIS) cascade. Our lab, in collaboration with researchers at University of Idaho, is manipulating IIS in various mosquito tissues to develop mosquitoes incapable of transmitting human pathogens such as malaria. A second major focus in our lab, in collaboration with researchers at UA and other institutions, is to understand the risk of dengue virus transmission in the Southern United States. Dengue is a mosquito transmitted virus that can cause fever, aches and in severe cases hemorrhaging and death. Although this virus is not yet found in the US, the primary mosquito vector is abundant. We are comparing mosquitoes from southern Arizona and dengue endemic areas in Northern Mexico to assess the risk of local dengue transmission. Specifically, we are examining mosquito population density, lifespan, blood-feeding preferences, the ability of the mosquitoes to transmit the virus and the virus developmental time in mosquito populations from southern Arizona and Northern Mexico. Keywords: Mosquito, vector-borne, arbovirus, malaria

Our lab investigates how the ecology of a species shapes patterns of variation at multiple levels (genes, pathways, transcriptomes, genomes, physiology, behavior and life history), how populations adapt to environmental shifts (natural or human created), how genetic architecture can dictate the evolutionary trajectory of populations, the implication of ecological adaptation in the process of speciation and the role of sexual selection and sexual conflict in the evolution of reproductive incompatibilities. Our research revolves around these fundamental aspects of evolutionary biology. We work on a group of cactophilic Drosophila that inhabit the deserts of North America. These Drosophila species are an excellent system to study given that their ecology is well understood and the fact that we can perform many genetic, genomic, manipulative and life history experiments. In addition to utilizing the cactophilic Drosophila system we have ongoing projects on the agrigenomics of the agricultural pests, Drosophila suzukii (spotted wing Drosophila) and Helicoverpa zea (corn earworm). Keywords: Evolutionary, ecological and agricultural genomics

Xianchun Li, PhD, is interested in understanding the physiological, biochemical, molecular and evolutionary bases of fundamental processes in the life history of insects such as embryonic polarity, metamorphosis, developmental commitment, host usage and environmental adaptation. One focus of his research is to elucidate the reciprocal signaling interactions between plants and insects, and the resulted on-going defense (in the case of plants) / counterdefense (in the case of herbivorous insects) phenotypic arm race over ecological time scale, with emphasis on the genetic machinery that percepts and transduces the reciprocal cues into genome and regulate defense / counterdefense phenotypes. Working systems include Helicoverpa zea, the corn earworm, a polyphagous noctuide of economic importance, and Drosophila melanogaster, the fruit fly, a model organism. State of arts and traditional techniques are combining to identify the cues and to uncover the signaling transduction cascade that links environmental cues, gene expression and the resulted defense/counterdefense phenotypes. This research may lead to characterization of genes for designing new insecticides and/or genetically modifying crops. The second focus of Dr. Li’s research is to define, globally, the regulatory triangle between nuclear receptors (NRs), their ligands, and cytochrome P450s (P450s) in Drosophila melanogaster. Nuclear receptors (NRs) constitute a transcription factor superfamily that has evolved to sense and bind endogenous (e.g., hormones) and/or exogenous (e.g., naturally-occurring or synthetic xenobiotics) signal compounds, resulting in differential expression of particular target genes, which underlies a range of fundamental biological processes, including growth, development, reproduction, behavior, host usage, and environmental adaptation. Many of those cue chemicals, namely NR ligands, are synthesized and/or metabolized by members of the P450s gene superfamily, whose expression may be regulated by certain NRs. Bioinformatics analyses as well as systematic functional genomic techniques such as microarray, X-ChIP, mutation and ectopic expression will be combined to define the genome-wide regulatory interaction loops between NRs and P450s as well as to assign, at least partially, functions of individual NRs and P450s in the life history of fruit fly. Given the evolutionary conservations of homologous NRs and P450s between vertebrates and invertebrates, the results obtained in this project are expected to provide insights into the reciprocal regulatory interactions between NRs and P450s in other animals including humans as well as to provide great insights into new avenue for human NR ligand identification and NR-related drug design. The third focus of his research is to investigate the molecular mechanisms of Bt and conventional insecticide resistance, which is a major threat in current IPM system. In collaboration with Dr. Bruce Tabashnik, Timothy Dennehy, and Yves Carriere in our Department, Dr. Li is going to compare Bt toxin binding affinity and other defects of natural (s, r1, r2, r3) and artificial mutant PBW (Pink Bollworm) cadherin proteins and thus define the key functional domains of PBW cadherin.

Martha Hunter, PhD, conducts research largely focused on understanding the evolutionary biology and ecology of parasitoids and predators important in biological control of agricultural pests. A group that has been central to much of her research are members of the aphelinid genus Encarsia, parasitoids of whiteflies and scale insects. Recently, the theme of her research has turned to the role of symbiotic microorganisms on the ecology and evolution of natural enemies. Dr. Hunter has found a bacterial symbiont in the Bacteroidetes, recently named Cardinium hertigii, that is unrelated to the better known proteobacterium, Wolbachia, but also manipulates the reproduction of is hosts in ways that enhances its transmission. Like Wolbachia, it induces parthenogenesis as well as cytoplasmic incompatibility in the autoparasitoid genus Encarsia, two reproductive phenotypes thought to be unique to Wolbachia.

Dawn H. Gouge, PhD, is a Specialist and Professor at the University of Arizona, College of Agriculture and Life Science, Department of Entomology. Dr. Gouge is well established in the U.S. as a community Integrated Pest Management expert and works with international partners in several countries. Dawn has published 38 original research papers and more than 80 extension publications, many in collaboration with investigators from around the world, authored 4 book chapters and co-edited a definitive Pest Management Strategic Plan. Dr. Gouge is a frequent presenter at national and international meetings, and serves as a steering committee organizer of the International IPM Symposium conference. Dawn has received11 awards for outstanding achievement and provides service on both National and Federal advisory committees. Dr. Gouge has led the charge in establishing higher pest management standards in children’s environments, reducing risks associated with pest and pesticide exposure. Keywords: arthropod vectors, bed bugs, Integrated pest managment

Peter Ellsworth, PhD, has broad interests in insect-crop interactions and applied insect ecology with particular emphasis on those aspects, which may be exploited for sound ecological and economical pest management. His responsibilities are to develop science-based solutions for integrated pest management through applied ecological investigations and organized outreach programs of Cooperative Extension, with principal focus on Bemisia tabaci, Lygus hesperus and Pectinophora gossypiella in the cotton agroecosystem, other field crops, and new crops as well as in cross-commodity interactions. In addition, Dr. Ellsworth is interested in insect phenology, diapause, insect-water relations, predictive modeling, pest biology, sampling, thresholds, and damage dynamics.As Director of the multi-disciplinary Arizona Pest Management Center, Dr. Ellsworth helps manage the institution's NIFA Extension IPM grant, serves as the state's federal IPM Coordinator and Pesticide Coordinator, and oversees and helps organize teams of research and extension faculty for the betterment of the science and application of IPM in Arizona.