Community Ecology, Population Dynamics, Tritrophic Interactions, Mutualisms, Symbioses.

Our current research involves understanding the response of insects to forest management through thinning and wildfire in pine forests, effects of tree characteristics and resin defense against insects, the role of bark beetles in influencing the structure and evolution of pine forest ecosystems, improving insect attractants, the effects of thinning piles on forest insect communities, and interactions among fungi, mites and bark beetles across multiple bark beetle communities. The National Science Foundation, USDA Competitive Grants Program, and USDA Forest Service support this research.

Bark beetles are integral components in forest ecosystems and can be viewed as beneficial or detrimental depending on the management objectives. Most bark beetles cause little or no economic damage as they normally infest branches, stumps, and stems of standing dead, severely weakened trees or downed material. Although all bark beetles are relatively small, 1mm to 8mm in length, several species attack and kill living, apparently healthy trees. In the southwest United States there are several important beetle species in the genus Ips and Dendroctonus that attack and kill large stands of conifers (http://www.fs.fed.us/r3/resources/health/beetle).

In Arizona, there are currently 30 known species of bark beetle that inhabit the Ponderosa pine. This complex of bark beetles offers an interesting community of study that is rarely found anywhere else in the world. There are many interesting questions, both applied and basic, that can be asked: How do we manage our forest to account for multiple beetle species and their pathogens? How does interspecific competition between species affect beetle population dynamics? Why do particular beetle species outbreak while others do not? Are fungi and mites associated with bark beetles switching among beetles hosts?

Contact Information

Fall 2008 Courses

Past Courses Taught

Education

B.S. University of Wisconsin, Madison, 1992
M.S. University of Wisconsin, Madison, 1996
Ph.D. Dartmouth College, 2003
Postdoctoral: Dartmouth College 2004

Selected Publications

Hofstetter, R.W. Mutualists (and phoronts) of the Southern Pine Beetle. In Southern Pine Beetle Encyclopedia (K.D. Klepzig & R. Coulson, eds.). Forest Encyclopedia Network (FEN) USDA Forest Service. 2008

Hofstetter, R.W., Z. Chen, M. Gaylord, J. McMillen & M. Wagner. 2008. Synergistic effects of the attractants á-pinene and exo-brevicomin on the southern and western pine beetle and associated predators in Arizona. J. Appl. Entomology (in press).

Hayes, C.J., T.E. DeGomez, J.D. McMillin, J.A. Anhold and R.W. Hofstetter. 2008. Factors Influencing Pine Engraver (Ips pini Say) Colonization of Ponderosa Pine (Pinus ponderosa Dougl. ex. Laws.) Slash in Northern Arizona. Forest Ecology and Management (in press).

Gaylord, M.L., K.B. Williams, R.W. Hofstetter, J.D. McMillin, T.E. DeGomez, & M.R. Wagner. 2008. Influence of temperature on spring flight initiation for southwestern ponderosa pine bark beetles (Coleoptera: Curculionidae, Scolytidae). Environmental Entomology 37:57-69.

Pureswaran, D.S., R.W. Hofstetter, & B. Sullivan. 2008. Attraction of the southern pine beetle, Dendroctonus frontalis to pheromone components of the western pine beetle, Dendroctonus brevicomis (Coleoptera: Curculionidae: Scolytinae) in an allopatric zone. Environmental Entomology 37: 70-78.

Hofstetter, R.W., J.C. Moser, and S. Blomquist. Mites associated with bark beetles and their hypophoretic fungi. In The Ophiostomatoid Fungi: Expanding Frontiers (Wingfield & Seifert, eds.). Submitted Nov. 2006, in print 2008.

Klepzig, K.D. & R.W. Hofstetter. From Attack to Emergence: Interactions between southern pine beetle, mites, microbes and trees. In The Ophiostomatoid Fungi: Expanding Frontiers (Wingfield & Seifert, eds.). Submitted Nov. 2006, in print 2008.

Martinson, S., M.P. Ayres & R.W. Hofstetter. 2007. Why does longleaf pine have low susceptibility to southern pine beetle? Can. J. For. Research 37: 1966-1977.

Hofstetter, R.W., T.D. Dempsey, K.D. Klepzig & M.P. Ayres. 2007. Temperature-dependent affects on mutualistic and phoretic associations. Community Ecology 8(1): 47-56.

Hofstetter, R.W., K. D. Klepzig, J.C. Moser & M.P. Ayres. 2006. Seasonal dynamics of mites and fungi and interactions with southern pine beetle. Environmental Entomology 35: 22-30.

Kolb, T.E., N. Guerard, M.R. Wagner, and R.W. Hofstetter. 2006. Attack preference of Ips pini in northern Arizona: tree size and bole position. Agriculture and Forest Entomology 8:295-303.

Hofstetter, R.W., J. Cronin, K. D. Klepzig, J.C. Moser & M.P. Ayres. 2006. Antagonisms, mutualisms and commensalisms affect outbreak dynamics of the southern pine beetle. Oecologia 147(4): 679-691.

Hofstetter, R. W., J. Mahfous, K. D. Klepzig, & M.P. Ayres. 2005. Effects of tree phytochemistry on the interactions between endophloedic fungi associated with the southern pine beetle. Journal of Chemical Ecology 31(3): 551-572.

Klepzig, K.D., J. Flores-Otero, R.W. Hofstetter & M.P. Ayres. 2004. Effects of available water on growth and competition of southern pine beetle associated fungi. Mycological Research 108: 183-188.

Lombardero, M.J., R.W. Hofstetter, M.P. Ayres, K. Klepzig & J. Moser. 2003. Strong indirect interactions among Tarsonemus mites (Acarina: Tarsonemidae) and Dendroctonus frontalis (Coleoptera: Scolytidae). Oikos 102: 342-352.

Veysey, J.S., M.P. Ayres, M.J. Lombardero, R.W. Hofstetter & K. Klepzig. 2003. The effect of host species on reproductive success of Dendroctonus frontalis (Coleoptera: Scolytidae). Environmental Entomology 32(2): 668-679.

Klepzig, K.D., J.C. Moser, F.J. Lombardero, R.W. Hofstetter & M.P. Ayres. 2001. Symbiosis & Competition: Complex interactions among beetles, fungi, and mites. Symbiosis 30:83-96.

Klepzig, K.D., J.C. Moser, F.J. Lombardero, M.P. Ayres, R.W. Hofstetter & C.J. Walkinshaw. 2001. Mutualism and antagonism: Ecological interactions among bark beetles, mites and fungi. Pp. 237-267. In: Biotic Interactions in Plant-Pathogen Associations (eds. M.J. Jeger & N.J. Spence). CAB International.

Landolt, P.J., J.A. Brumley, C.L. Smithhisler, L.L. Biddick & R.W. Hofstetter. 2000. Apple fruit infested with codling moth are more attractive to neonate codling moth larvae and possess increased amounts of (E,E)-á-Farnesene. Journal of Chemical Ecology 26(7):1685-1699.

Landolt, P.J., R.W. Hofstetter & L.L. Biddick. 1999. Plant essential oils as arrestants and repellents for neonate larvae of the codling moth (Lepidoptera: Tortricidae). Environmental Entomology 28(6): 954-960.

Landolt, P.J., R.W. Hofstetter & P.S. Chapman. 1998. Neonate codling moth larvae (Lep.: Tortricidae) orient anemotactically to odor of immature apple fruit. Pan-Pacific Entomologist 74(3): 140-149.

Hofstetter, R.W. & K.F. Raffa. 1998 . Endogenous and external factors affecting parasitism of gypsy moth egg masses by Ooencyrtus kuvanae (Hymenoptera: Encyrtidae). Ent. Exp. Appl. 88: 123-135.

Hofstetter, R.W. & K.F. Raffa. 1997. Effects of host's diet on the orientation, development, and subsequent generations of the egg parasitoid, Ooencyrtus kuvanae. Environmental Entomology 26(6): 1276-1282.

Hofstetter, R.W. & K.F. Raffa. 1996. Parasitism of pine tussock moth eggs by the gypsy moth parasite, Ooencyrtus kuvanae. Ent. News 108(1): 63-65.

Last Updated ( Wednesday, 13 August 2008 )