Lien T. Luong Postdoctoral Fellow Ph.D. University of California, Davis
Address: Lien T. Luong Department of Biological Sciences, ML006 University of Cincinnati Cincinnati, Ohio 45221-0006	Telephone: (513) 556-9736 FAX: (513) 556-5299 Email: luongl@email.uc.edu

My general research interests encompass areas of behavioral ecology, evolutionary biology, and parasite-host interactions, and the intersection of these fields. As a postdoctoral fellow in Dr. Michal Polak’s laboratory, my research focuses on the relationship between a cactophilic drosophilid species and its ectoparasitic mite. Specifically, I am investigating 1) the effect of reduced genetic variation on disease susceptibility, and its underlying mechanism and 2) the genetic costs associated with resistance against parasitism.

In the first project, I tested the hypothesis that inbreeding compromises resistance against parasitism in a natural fruit fly (Drosophila nigrospiracula) – mite (Macrocheles subbadius) system (photo - right top;  scanning electron micrograph right bottom). I demonstrated that host inbreeding increases susceptibility to ectoparasitism, and that this outcome was mediated by host behavior. Specifically, inbreeding reduced the host’s ability to sustain energetically expensive behaviors, and that host exhaustion dramatically increased susceptibility. I argued that inbreeding depression for resistance results from an inability to sustain defensive behaviors because of compromised physiological competence (Luong et al., 2006).

In the second project, I am examining fitness costs associated with a behaviorally-mediated resistance in the above fly-mite system. Genetic trade-offs between resistance and other host fitness components are detectable by way of correlated responses to artificial selection for resistance. I showed that fecundity is negatively correlated with resistance and that this effect is context dependent. These findings confirm the hypothesis that evolutionary trade-offs between resistance and other host fitness traits contribute to the maintenance of genetic variation for resistance in natural populations (Luong and Polak, in preparation).

Luong, L.T. and Polak, M.  Parasites inhibit host copulation: a novel mechanism of parasite-mediated sexual selection. In prep.
Luong, L. T. and Polak, M.  Costs of Resistance: genetic trade-offs between parasite resistance and host fitness traits. In prep.
Hinkle, N.C., Luong, L.T., and Platzer, E.G.  Poultry tapeworms, Choanotaenia infundibulum and Raillietina cesticillus: extrinsic incubation and seasonality. In prep.
Luong, L. T., Heath, B. D., and Polak, M. 2006.  Host inbreeding increases susceptibility to ectoparasitism. Journal of Evolutionary Biology. in press
Luong, L. T., Kortet, R.,and Hedrick, A. V.  2005.  Prevalence and intensity of Cephalobium microbivorum (Nematoda: Diplogasterida) infection in three species of Gryllus field crickets.  Parasitology Research 97: 336-339.
Luong, L.T. and Kaya, K.H. 2005b.  Sexually transmitted parasites and host mating behavior in the decorated cricket. Behavioral Ecology 16:794-799.
Luong, L.T. and Kaya, K.H.  2005a.  Sexually transmitted nematodes affect nuptial food gift production in the cricket, Gryllodes sigillatus.  Behavioral Ecology 16:153-158.
Luong, L.T. and Kaya, K.H.  2002.  Infection dynamics of a sexually transmitted nematode (Mehdinema alii) in the decorated cricket (Gryllodes sigillatus). Canadian Journal of Zoology 80: 1145-1148.
Luong, L.T., Platzer, E. G., Zuk, M., and Giblin-Davis, R. M.  2000.  Venereal worms: sexually transmitted nematodes in the decorated cricket.  Journal of Parasitology  86: 471-477.
Luong, L. T., Platzer, E. G., De Ley, P., and Thomas, K.  1999.  Morphological characterization and biology of Mehdinema alii (Nematoda: Diplogasterida) from the decorated cricket (Gryllodes sigillatus).  Journal of Parasitology 85: 1053-1064.
Zuk, M., Kim, T., Kristan, D.M., and Luong, L.T.  1997.  Sex, Pain and Parasites.  Parasitology Today 13: 332-333.