Claus Tittiger

Photo of Claus Tittiger

Professor - Department Chair

Department of Biochemistry and Molecular Biology
University of Nevada/Mail Stop 330
1664 North Virginia Street
Reno,  Nevada   89557

Office: (775) 784-6480
Lab: 784-1734

Fax: 784-1419

Building: Howard Medical Science,  Office 154

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B.Sc. Biochemistry, 1987 University of Ottawa
Ph.D. Biology, 1994 Queens University, Kingston, Ontario, Canada


We use functional genomics, molecular biology, and biochemical techniques to understand bark beetles and their interactions with host trees.  We are concentrating on two areas: the enzymes involved in isoprenoid pheromone biosynthetic pathways and the ability of the beetle to metabolize toxic resin components.

Pine bark beetles, while physically very small, can kill vast areas of coniferous forest during outbreak conditions. The increased forest fire risk and loss of timber are significant economic costs associated with bark beetle activity. Research in my lab focuses on understanding various aspects of the bark beetles’ biochemistry in order to better develop targeted control strategies. Our long term goal is to specifically regulate bark beetle populations, at least in an urban setting, without harming non-target organisms. There are two broad subject areas under study:

Pheromone Biosynthesis:Bark beetle outbreaks are mediated by aggregation pheromones, many of which are monoterpenes.  Since de novo monoterpene synthesis in the Metazoa is rare, the pheromone biosynthetic pathway is an attractive target for eventual control strategies.  Monoterpenoid pheromone components are synthesized in the midgut via the mevalonate (isoprenoid) pathway, with carbon likely being shunted away from the mevalonate pathway and into the pheromone pathway at geranyl diphosphate.


Phloem Detoxification:   Pine trees are full of toxic resin, which discourages animals from eating them.  The resin contains mostly monoterpenoid solvents  --turpentine and Pinesol are produced from pine trees-- and considering that drinking a medium-sized glass of turpentine is enough to kill most humans (not recommended, don’t try it!), it is remarkable that bark beetles can thrive in their environment.  Since different beetle species are more or less restricted to their host tree species, their detoxification processes are probably “tuned” to their host tree.  We are trying to understand the biochemical mechanisms the beetles use to survive constant monoterpene ingestion.


  • BCH 405-605 - Molecular Biology (supported by WebCampus)


Book or Chapter(s) in Books
Tittiger, C., Blomquist, G. 2016, Pheromone production in bark beetles., In C Tittiger and GJ Blomquist (Ed.), Advances in Insect Physiology (vol. 50, pp. 235-263). Advances in Insect Physiology/Elsevier.
Tittiger, C., Blomquist, G. 2016, Pine Bark Beetles, In Tittiger, C and Blomquist, GJ (Ed.), (pp. 304). Advances in Insect Physiology
Song, M., Delaplain, P., Nguyen, T. T., Liu, X., Wickenberg, L., Jeffrey, C., Blomquist, G., Tittiger, C. 2014, Exo-Brevicomin biosynthetic pathway enzymes from the Mountain Pine Beetle, Dendroctonus ponderosae., Insect Biochemistry and Molecular Biology, 53, 73-80. View item.
Keeling, C. K., Chiu, C. C., Aw, T., Li, M., Tittiger, C., Weng, H., Blomquist, G., Bohlman, J. 2013, Frontalin pheromone biosynthesis in the mountain pine beetle, Dendroctonus ponderosae Hopkins, role of isoprenyldiphosphate synthases., Proceedings of the National Academy of Sciences, 110, 18838-18843.
Qiu, Y., Tittiger, C., Wicker-Thomas, C., LeGoff, G., Young, S., Wajnberg, E., Fricaux, T., Taquet, N., Blomquist, G. J., Feyereisen, R. 2012, An insect-specific P450 oxidative decarnonylase for cuticular hydrocarbon biosynthesis., Proceedings of the National Academy of Sciences, U.S.A., 109(37), 14853-14863.
Figueroa-Teran R, Welch WH, Blomquist GJ, Tittiger C. 2012, Ipsdienol dehydrogenase (IDOLDH): a novel oxidoreductase important for Ips pini pheromone production., Insect Biochem Mol Biol. 2012 Feb;42(2):81-90.
Blomquist, G., Figueroa-Teran, R., Aw, M., Song, M., Gorzalski, A., Abbott, N. L., Chang, E., Tittiger, C. 2010, Pheromone production in bark beetles., Insect Biochemistry and Molecular Biology, 40, 699-712.
Taban, H., Tittiger, C., Blomquist, G., Welch, W. H. 2009, Isolation and characterization of farnesyl diphosphate synthase from the cotton boll weevil, Anthonomus grandis., Archives of Insect Biochemistry and Physiology, 71(2), 88-104.
Bearfield, J. C., Henry, A. G., Tittiger, C., Blomquist, G., Ginzel, M. D. 2009, Two regulatory mechanisms of monoterpenoid pheromone production in Ips spp. of bark beetles., J. Chemical Ecology, 35, 689-697.
Bark beetles use aggregation pheromones to coordinate host colonization and mating. These monoterpenoid chemical signals are produced de novo in midgut cells via the mevalonate pathway, and pheromone production is induced when an adult beetle feeds on phloem of a host tree. In Ips pini, juvenile hormone (JH) III influences key regulatory enzymes along the mevalonate pathway that lead to pheromone production. In fact, topically applied JH III is sufficient to stimulate pheromone production in unfed males. In this study, we explore the influence of feeding and JH III on pheromone production in male Ips confusus, the pinyon Ips. We also characterize the influence of feeding and JH III treatment on transcript levels and activity of three key enzymes involved in pheromone biosynthesis: 3-hydroxy-3-methylglutaryl-CoA (HMG) synthase (HMGS), HMG-CoA reductase (HMGR) and geranyl diphosphate synthase (GPPS). Feeding on host phloem alone strongly induces pheromone production in male I. confusus, while JH III treatment has no effect. However, feeding and JH III both significantly up-regulate mRNA levels of key mevalonate pathway genes. Feeding, but not JH III treatment, also increases the activity of all three enzymes. Our data suggest that pheromone production in Ips is not uniformly controlled by JH III and feeding may stimulate the release of some other regulatory factor, perhaps a brain hormone, required for pheromone production.
Gilg, A. B., Tittiger, C., Blomquist, G. 2009, Unique animal prenyltransferase with monoterpene synthase activity., Naturwissenschaften, 96, 731-735.
J.C. Bearfield, C.D. Box, C.I. Keeling, S. Young, G.J. Blomquist and C. Tittiger 2008, Isolation, endocrine regulation and transcript distribution of a putative primary JH-responsive gene from the pine engraver, Ips pini (Coleoptera: Scolytidae), Insect Biochem. Molec. Biol. 38: 256-267 View item.
P. Sandstrom, M.D. Ginzel, J.C. Bearfield, W.H. Welch, G.J. Blomquist, and C. Tittiger 2008, Myrcene hydroxylases do not determine enantiomeric composition of pheromonal ipsdienol in Ips spp., J. Chem. Ecol. 34:1584-1592. View item.
M. D. Ginzel, J. C. Bearfield, C. I. Keeling, C. C. McCormack, G. J. Blomquist and C. Tittiger 2007, Antennally-mediated negative-feedback regulation of pheromone production in the pine engraver beetle, Ips pini., Naturwissenschaften. 91:61-64. View item.
C. I. Keeling, J. C. Bearfield, S. Young, G. J. Blomquist and C. Tittiger 2006, Effects of juvenile hormone on gene expression in the pheromone-producing midgut of the pine engraver beetle, Ips pini, Insect Molec. Biol. 15, 207-216 View item.
P. Sandstrom, W. H. Welch, G. J. Blomquist and C. Tittiger 2006, Functional expression of a bark beetle cytochrome P450 that hydroxylates myrcene to ipsdienol, Insect Biochem. Molec. Biol. 36, 835-845 View item.
J. C. Bearfield, C. I. Keeling, S. Young, G. J. Blomquist and C. Tittiger 2006, Isolation, endocrine regulation, and mRNA distribution of the 3-hydroxy-3-methylglutaryl coenzyme A synthase (HMG-S) gene from the pine engraver, Ips pini, Insect Molec. Biol. 15, 187-195 View item.
Taban, A. H., J. Fu, J. Blake, A. Awano, C. Tittiger and G. J. Blomquist 2006, Site of pheromone biosynthesis and isolation of HMG-CoA reductase cDNA in the cotton boll weevil, Anthonomus grandis, Arch. Insect Biochem. Biophys. 62, 153-163 View item.
A. B. Gilg, J. C. Bearfield, C. Tittiger, W. H. Welch and G. J. Blomquist, 2005. Isolation and functional expression of the first animal geranyl diphosphate synthase and its role in bark beetle pheromone biosynthesis. Proc. Nat. Acad. Sci. U.S.A. 102, 9760-9765. 2005, Isolation and functional expression of the first animal geranyl diphosphate synthase and its role in bark beetle pheromone biosynthesis, Proc. Nat. Acad. Sci. U.S.A. 102, 9760-9765 View item.
C. Tittiger, C. I. Keeling and G. J. Blomquist 2005, Some insights into the remarkable metabolism of the bark beetle midgut, Recent Adv. Phytochem. 39, 57-78
Keeling, C.I., G.J. Blomquist, and C. Tittiger 2004, Coordinated gene expression for pheromone biosynthesis in the pine engraver beetle, Ips pini (Say) (Coleoptera: Scolytidae), Naturwissenschaften 91: 324-328 View item.
C. Tittiger 2004, Functional Genomics and Insect Chemical Ecology, J. Chem. Ecol. 30, 2335-2358 View item.
J.A. Tillman, F. Lu, L. Staehle, Z. Donaldson, S.C. Dwinell, C. Tittiger, G.M. Hall, A.J. Storer, G.J. Blomquist and S.J. Seybold 2004, Juvenile hormone regulates de novo isoprenoid aggregation pheromone biosynthesis in pine bark beetles, Ips spp. (Coleoptera: Scolytidae), through transcriptional control of HMG-CoA reductase, J. Chem. Ecol. 30, 2459-2494 View item.
S.J. Seybold and C. Tittiger (2003) Biochemistry and molecular biology of de novo isoprenoid pheromone production in the Scolytidae. Ann Rev. Entomol. 48: 425-453. 2003, Biochemistry and molecular biology of de novo isoprenoid pheromone production in the Scolytidae, Ann Rev. Entomol. 48: 425-453 View item.
A.L. Eigenheer, C.I. Keeling, S. Young and C. Tittiger 2003, Comparison of gene representation from two phytophagous insects, Bombyx mori and Ips pini using expressed sequence tags, Gene. 316C: 127-136 View item.
C. Tittiger, L.S. Barkawi, C.S. Bengoa, G.J. Blomquist and S.J. Seybold 2003, Structure and juvenile hormone-mediated regulation of the HMG-CoA reductase gene from the Jeffrey pine beetle, Dendroctonus jeffrey, Mol. Cel. Endocrin. 199, 11-21 View item.
M.H. Riddervold, C. Tittiger, G.J. Blomquist and C.E. Borgeson 2002, Biochemical and molecular characterization of house cricket (Acheta domesticus, Orthoptera: Gryllidae) delta-9 desaturase, Insect Biochem. Molec. Biol. 32: 1731-1740 View item.
A. Eigenheer, S. Young, G.J. Blomquist, C.E. Borgeson and C. Tittiger 2002, Isolation and molecular characterization of Musca domestica delta-9 desaturase sequences, Insect Molec. Biol. 11: 533-542 View item.
G.M. Hall,, C. Tittiger, G.L. Andrews, G.S. Mastick, M. Kuenzli, S.J. Seybold and G.J. Blomqust 2002, Male Jeffery pine beetles, Dendroctonus jeffreyi, synthesize the pheromone component frontalin de novo in anterior midgut tissue, Insect Biochem. Molec. Biol. 32: 1525-1532 View item.
G.M. Hall, C. Tittiger, G.L. Andrews, G.S. Mastick, M. Kuenzli, X. Luo, S.J. Seybold and G.J. Blomquist 2002, Midgut tissue of male pine engraver, Ips pini, synthesizes monoterpenoid pheromone component ipsdienol de novo, Naturwissenschaften. 89: 79-83 View item.
J.B. Nardi, A.G. Young, E. Ujhelyi, C. Tittiger, M.J. Trehane and G.J. Blomquist 2002, Specialization of midgut cells for synthesis of male aggregation pheromone in two scolytid beetles, Dendroctonus jeffreyi and Ips pini, Tissue and Cell. Aug(34): 221-232. View item.
Cinnamon, E., Makki, R., Sawala, A., Wickenberg, L., Huestis, D., Blomquist, G., Tittiger, C., Paroush, Z., Gould, A. 2016, Drosphila Spidey/Kar regulates oenocyte growth via P13-kinase signaling., PLOS GENETICS, 12(8), e1006154
Figueroa, R., Pak, H., Blomquist, G., Tittiger, C. 2016, High substrate specificity of ipsdienol dehydrogenase (IDOLDH), a short chain dehydrogenase from Ips pini bark beetles., Journal of Biochemistry, 160, 141-151 View item.
Balibanidou, V., Kambouraki, A., MacLean, M., Blomquist, G. J., Tittiger, C., Juarez, M., Mijailovsky, S., Chalepakis, G., Anthousi, A., Hemmingway, J., Antoine, S., Lynd, A., Lycett, G., Vontas, J. 2016, Cytochromes P450 associated with insecticide resistance catalyse cuticular hydrocarbon production in Anopheles gambiae., Proceedings of the National Academy of Sciences, USA, 113(33), 9268-9273.