Department of Entomology

Christen, Jayne

Christen, Jayne Masters 2005
Biochemistry Department Manhattan Kansas jmc1639@ksu.eduDegree Being Pursued: Ph.D.

Bio Brief

Bacterial, nematode, and insect interactions during the Steinernema riobrave host infection process

Education

B.S. Secondary Education, Kansas State University, 2003

Research

Entomopathogenic nematodes are lethal endoparasites of insects and have been extensively studied as biological control agents. The only free-living stage is the infective juvenile that actively forages and infects a new host. Although much is known about host infection behavior, little is known about the specific sensory cues used in host finding and assessment. In addition to unparasitized hosts, entomopathogenic nematode infective stages can encounter potential hosts that are already parasitized. The quality of the insect as a resource will change depending on the stage of infection and entomopathogenic nematode behavioral response has been shown to differ depending on the stage of parasitization. The specific chemical changes that occur during parasitization that might be used to evaluate host status are not known. The goal of this research project is to develop a better understanding of the chemical changes to the host during the process of nematode parasitization and how these changes may influence the infection behavior.

Specific research objectives are to:

  1. Determine changes in volatile chemicals emitted by an insect during entomopathogenic nematode parasitization,
  2. Determine changes in non-volatile chemicals on the cuticle of host insects during entomopathogenic nematode parasitization,
  3. Evaluate the influence of specific chemical changes on entomopathogenic nematode infective juvenile behavior,
  4. Determine changes in the bacterial population in host insect species after infection by entomopathogenic nematodes


Publications

Ramos-Rodriguez, O., J.F. Campbell, J.M. Christen, D.I. Shapiro-Ilan, E.E. Lewis and S.B. Ramaswamy. 2007. Attraction behaviour of three entomopathogenic nematode species towards infected and uninfected hosts. Parasitology 134: 729-738


Christen, J.M., J.F. Campbell, E.E. Lewis, D.I. Shapiro-Ilan and S.B. Ramaswamy. 2007. Responses of the entomopathogenic nematode, Steinernema riobrave to its insect hosts, Galleria mellonella and Tenbrio molitor. Parasitology 134: 889-898


Christen, J.M., Campbell, J.F. and Ramaswamy, S.B. 2006. Responses of the entomopathogenic nematode, Steinernema riobrave, to its insects hosts, Galleria mellonella and Tenbrio molitor. Parasitology (in press)


Christen, J.M., Campbell, J.F., Zurek, L. and Ramaswamy, S.B. 2006. Role of symbiotic bacteria (Xenorhabdus sp.) in the host-infection process of Steinernema riobrave. Journal of Invertebrate Pathology (in press)