Visiting Associate Professor of Biology
3203 SE Woodstock Blvd.
Portland, OR 97202
Before joining the Reed Biology faculty Todd received his B.A. in Integrative Biology from UC Berkeley and his Ph.D. in Zoology from UT Austin. He was a postdoc at UC Davis and an NIH-NRSA postdoctoral fellow at Cornell University, before spending six years on the faculty at Emory University.
Research in the Schlenke lab is rooted in evolutionary biology and genetics, but also spans several other research areas, including ecology, immunology, cell and molecular biology, and bioinformatics. We are especially interested in host-parasite interactions, from the population level down to the molecular level. In particular, we study fruit flies and their parasitic wasps.
(see below for more detail)
(Click here for one of our wasp attack videos.)
BIO246 Molecular Evolution: This course covers broad topics in the field of molecular evolution, including genome structure, population genetics, and bioinformatic and phylogenetic methods, with the goal of understanding the demographic and selective forces shaping genomes. (lecture 0.5 units, Spring term)
BIO315 Evolutionary Biology: This course covers the history and current status of major research areas in evolutionary biology including mechanisms of evolutionary change, adaptation, speciation, and the history of life. The lectures rely heavily on recent articles from the primary literature, while the lab focuses on practical applications of evolutionary biology and outdoor exploration of the diversity of life. Each student will contribute to a class artificial selection experiment in flies, and will also undertake their own adaptation experiments. (lecture/lab 1.0 units, Fall term)BIO431 Origins and Evolution of the Immune System: This course is focused on the comparative immunology of prokaryotes, protozoans, plants, fungi, invertebrates, and “lower” vertebrates. The class is aimed at teaching students to see evolutionary patterns that help explain how our own immune system developed from those of our ancestors. Such comparative study highlights the strengths and weaknesses of our immune system, and points to ways in which other organisms have overcome the same pathogenic stresses we currently face. (seminar 0.5 units, Spring term)
Fly cellular immunity and wasp virulence
Parasitic wasps lay their eggs in fruit fly larvae, inducing a complex host cellular immune response termed melanotic encapsulation that is similar to granuloma formation in vertebrates. Wasps inject venom into flies to suppress this immune response. Our lab identifies candidate fly cellular immunity genes and wasp venom genes using a variety of mapping and ‘omics’ approaches, then functionally characterizes those candidate genes at the molecular level.
Fly behavioral defenses against wasps
Our lab has identified three kinds of behavioral immune mechanisms flies use to prevent wasp infection or to cure themselves once infected, and we've started to characterize the genetic basis for these behaviors. First, infected fly larvae therapeutically medicate themselves by consuming plant and fungal secondary metabolites they are resistant to. Second, adult flies prophylactically medicate their offspring by laying their eggs in substrates with high secondary metabolite concentrations when they sense wasp presence in their environments. Third, adult flies decrease egg production in the presence of wasps, presumably because the eggs they produce are better-provisioned for mounting anti-wasp immune responses later in life.
Coevolution of host defense and parasite virulence
We are interested in long-term patterns of immune system and virulence protein evolution. For example, in previous work, we showed that it is Dr osophila anti-bacterial immune signaling proteins, not recognition or attack proteins, that rapidly evolve, suggesting that the most common microbial infection strategies involve active suppression of host immune signaling rather than passive evasion. Which fly immune proteins and wasp virulence proteins mediate their evolutionary arms race? The fruit fly-wasp interaction can also be exploited to answer general questions about the evolution and ecology of host-pathogen interactions, such as (1) whether different kinds of host immune mechanisms (cellular, behavioral...) tend to trade off with one another over evolutionary time, (2) how within-host competition favors different types of parasite life histories, and (3) whether generalist parasites tend to be more immune suppressive and less immune evasive than specialist parasites.
Fruit flies diversify their offspring in response to parasite infection Singh ND, Criscoe DR, Skolfield S, Kohl KP, Keebaugh ES, Schlenke TA Science, in press
Insights from natural host-parasite interactions: The Drosophila model Keebaugh ES, Schlenke TA Developmental and Comparative Immunology 42, 111-123 (2013) link
A role for nematocytes in the cellular immune response of the Drosophilid Zaprionus indianus Kacsoh BZ, Bozler J, Schlenke TA Parasitology 141, 697-715 (2013) link
Parasitoid wasp venom SERCA regulates Drosophila calcium levels and inhibits cellular immunity Mortimer NT, Goecks J, Kacsoh BZ, Mobley JA, Bowersock GJ, Taylor J, Schlenke TA PNAS 110, 9427- 9432 (2013) link
Integrative approach reveals composition of endoparasitoid wasp venoms Goecks J, Mortimer NT, Mobley JA, Bowersock GJ, Taylor J, Schlenke TA PLoS One 8, e64125 (2013) link
Fruit flies medicate offspring after seeing parasites Kacsoh BZ, Lynch ZR, Mortimer NT, Schlenke TA Science 339, 947-950 (2013) link
Mgat1-dependent N-glycosylation of membrane components primes Drosophila melanogaster blood cells for the cellular encapsulation response Mortimer NT, Kacsoh BZ, Keebaugh ES, Schlenke TA PLoS Pathogens 8, e1002819 (2012) link
High hemocyte load is associated with increased resistance against parasitoids in Drosophila suzukii, a relative of D. melanogaster Kacsoh BZ, Schlenke TA PLoS One 7, e34721 (2012) link
Alcohol consumption as self-medication against blood-borne parasites in the fruit fly Milan NF, Kacsoh BZ, Schlenke TA Current Biology 22, 488-493 (2012) link