Theoretical Ecology

, Volume 1, Issue 3, pp 163–177 | Cite as

Connecting host physiology to host resistance in the conifer-bark beetle system

  • William A. NelsonEmail author
  • Mark A. Lewis
Original Paper


Host defenses can generate Allee effects in pathogen populations when the ability of the pathogen to overwhelm the defense system is density-dependent. The host–pathogen interaction between conifer hosts and bark beetles is a good example of such a system. If the density of attacking beetles on a host tree is lower than a critical threshold, the host repels the attack and kills the beetles. If attack densities are above the threshold, then beetles kill the host tree and successfully reproduce. While the threshold has been found to correlate strongly with host growth, an explicit link between host physiology and host defense has not been established. In this article, we revisit published models for conifer-bark beetle interactions and demonstrate that the stability of the steady states is not consistent with empirical observations. Based on these results, we develop a new model that explicitly describes host damage caused by the pathogen and use the physiological characteristics of the host to relate host growth to defense. We parameterize the model for mountain pine beetles and compare model predictions with independent data on the threshold for successful attack. The agreement between model prediction and the observed threshold suggests the new model is an effective description of the host–pathogen interaction. As a result of the link between the host–pathogen interaction and the emergent Allee effect, our model can be used to better understand how the characteristics of different bark beetle and host species influence host–pathogen dynamics in this system.


Host–pathogen models Attack threshold Allee effect Bark beetles Resin defenses Mountain pine beetles Carbon budget model 



We would like to thank Alex Potapov and Frank Hilker for independently solving the phase-plane trajectories used in Appendix B, and two anonymous reviewers who helped improve the manuscript. This study was funded by Natural Resources Canada–Canadian Forest Service under the Mountain Pine Beetle Initiative. Publication does not necessarily signify that the contents of this report reflect the views or policies of Natural Resources Canada–Canadian Forest Service. Additional support was provided by Natural Sciences and Engineering Research Council (NSERC) and Alberta Ingenuity Postdoctoral fellowships to WAN and NSERC Discovery grants and Canada Research Chairs to MAL.


  1. Allee W (1931) Animal aggregations. The University of Chicago Press, ChicagoGoogle Scholar
  2. Berryman A (1979) Dynamics of bark beetle populations: analysis of dispersal and redistribution. Bull Soc Entomol Suisse 52:227–234Google Scholar
  3. Berryman A, Stenseth N (1989) A theoretical basis for understanding and manaing biological populations with particular reference to the spruce bark beetle. Holarct Ecol 12:387–394Google Scholar
  4. Berryman A, Raffa K, Millstein J, Stenseth N (1989) Interaction dynamics of bark beetle aggregation and conifer defense rates. OIKOS 56:256–263CrossRefGoogle Scholar
  5. Bond-Lamberty B, Wang W, Gower S (2002) Aboveground and belowground biomass and sapwood area allometric equations for six boreal tree species of northern alberta. Can J For Res 32:1441–1450CrossRefGoogle Scholar
  6. Bouffier L, Gartner B, Domec J (2003) Wood density and hydraulic properties of ponderosa pine from the willamette valley vs. the cascade mountains. Wood Fiber Sci 35(2):217–233Google Scholar
  7. Callaway R, DeLucia E, Schlesinger W (1994) Biomass allocation of montane and desert ponderosa pine: an analog for response to climate change. Ecology 75(5):1474–1481CrossRefGoogle Scholar
  8. Christiansen E, Waring R, Berryman A (1987) Resistance of confiers to bark beetle attack: searching for general relationships. For Ecol Manag 22:89–106CrossRefGoogle Scholar
  9. Courchamp F, Clutton-Brock T, Grenfell B (1999) Inverse density dependence and the allee effect. Trends Ecol Evol 14(10):405–410CrossRefGoogle Scholar
  10. Czimezik C, Preston C, Schmidt M, Werner R, Schulze E (2002) Effects of charring on mass, organic carbon, and stable carbon isotope composition of wood. Org Geochem 33:1207–1223CrossRefGoogle Scholar
  11. Franceschi V, Krokene P, Christiansen E, Krekling T (2005) Anatomical and chemical defenses of conifer bark against bark beetles and other pests. New Phytol 167:353–376PubMedCrossRefGoogle Scholar
  12. Gershenzon J (1994) Metabolic cost of terpenoid accumulation in higher plants. J Chem Ecol 20(6):1281–1328CrossRefGoogle Scholar
  13. Kirisits T, Offenthaler I (2002) Xylem sap flow of norway spruce after inocluation with the blue stain fungus Ceratocystis polonica. Plant Pathol 51:359–364CrossRefGoogle Scholar
  14. Lavigne M, Ryan M (1997) Growth and maintenance respiration rates of aspen, black spruce and jack pine stems at northern and southern boreas sites. Tree Physiol 17:543–551PubMedGoogle Scholar
  15. Lewinsohn E, Gijzen M, Croteau R (1991) Defence mechanisms of conifers. Plant Physiol 96:44–49PubMedGoogle Scholar
  16. Logan J, Powell J (2001) Ghost forests, global warming, and the mountain pine beetle. Am Entomol 47:160–173Google Scholar
  17. Lombardero ML, Ayres MP, Lorio PL Jr, Ruel JJ (2000) Environmental effects on constitutive and inducible defences of Pinus taeda. Ecol Lett 3:329–339CrossRefGoogle Scholar
  18. Loomis W (1932) Growth-differentiation balance vs. carbohydrate-nitrogen ratio. Proc Am Soc Hortic Sci 29:240–245Google Scholar
  19. Miller R, Berryman A (1986) Carbohydrate allocation and mountain pine beetle attack in girdled lodgepole pines. Can J For Res 16(5):1036–1040CrossRefGoogle Scholar
  20. Mulock P, Christiansen E (1986) The threshold of successful attack by Ips typographus on Picea abies: a field experiment. For Ecol Manag 14:125–132CrossRefGoogle Scholar
  21. Ogden N, Casey A, French N, Adams J, Woldehiwet Z (2002) Field evidence for density-dependent facilitation amongst Ixodes ricinus ticks feeding on sheep. Parasitology 124:117–125PubMedGoogle Scholar
  22. Penning de Vries F (1975) Use of assimilates in higher plants. In: Cooper JP (ed) Photosynthesis and productivity in different environments. Cambridge Unviersity Press, Cambridge, pp 459–480Google Scholar
  23. Powell J, Logan J, Bentz B (1996) Local projections for a global model of mountain pine beetle attacks. J Theor Biol 179(3):243–260CrossRefGoogle Scholar
  24. Raffa K (2001) Mixed messages across multiple trophic levels: the ecology of bark beetle chemical communication systems. Chemoecology 11:49–65CrossRefGoogle Scholar
  25. Raffa K, Berryman A (1983) The role of host plant resistance in the colonization behavior and ecology of bark beetles (coleoptera:scolytidae). Ecol Monogr 53(1):27–49CrossRefGoogle Scholar
  26. Raffa K, Smalley E (1995) Interaction of pree-attack and induced monoterpene concentrations in host conifer defense against bark beetle-fungal complexes. Oecologia 102:285–295CrossRefGoogle Scholar
  27. Raffa K, Aukema B, Erbilgin N, Klepzig K, Wallin K (2005) Interactions among conifer terpenoids and bark beeltes across multipls levels of scale: an attempt to understand links between population patterns and physiological processes. Recent Adv Phytochem 39:79–118CrossRefGoogle Scholar
  28. Reid R, Whitney H, Watson J (1967) Reactions of lodgepole pine to attack by Dendroctonus ponderosae hopkins and blue stain fungi. Can J Bot 45:1115–1126CrossRefGoogle Scholar
  29. Stenseth N (1989) A model for the conquest of a tree by bark beetles. Holarct Ecol 12:408–414Google Scholar
  30. Thompson M, Holbrook N (2003) Scaling phloem transport: water potential equilibrium and osmoregulatory flow. Plant Cell Environ 26:1561–1577CrossRefGoogle Scholar
  31. Trapp S, Croteau R (2001) Defensive resin biosynthesis in conifers. Annu Rev Plant Physiol Plant Mol Biol 52:689–724PubMedCrossRefGoogle Scholar
  32. Turtola A, Manninen A, Rikala R, Kainulainen P (2003) Drought stress alters the concentration of wood terpenoids in scots pine and norway spruce seedlings. J Chem Ecol 29(9):1981–1995PubMedCrossRefGoogle Scholar
  33. Uma Devi K, Uma Maheswara Rao C (2006) Allee effect in the infection dynamics of the entomopathogenic fungus Beaveria bassiana (bals) vuill. on the beetle, Mylabris pustulata. Mycopathologia 161:385–394PubMedCrossRefGoogle Scholar
  34. Vanninen P, Mäkelä A (2005) Carbon budget for scots pine trees: effect of size, competition and site fertility on growth allocation and production. Tree Physiol 25:17–30PubMedGoogle Scholar
  35. Wallin K, Raffa K (1999) Altered constitutive and inducible phloem monoterpenes following natural defoliation of jack pine: implications to host mediated interguild interactions and plant defense theories. J Chem Ecol 25(4):861–880CrossRefGoogle Scholar
  36. Wallin K, Raffa K (2001) Effects of folivory on subcortical plant defenses: can defense theories predict interguild processes? Ecology 82(5):1387–1400CrossRefGoogle Scholar
  37. Waring R, Pitman G (1985) Modifying lodgepole pine stands to change susceptibility to mountain pine beetle attack. Ecology 66(3):889–897CrossRefGoogle Scholar
  38. Waring R, Thies W, Muscato D (1980) Stem growth per unit of leaf area: a measure of tree vigor. For Sci 1:112–117Google Scholar
  39. Zausen G, Kolb T, Bailey J, Wagner M (2005) Long-term impacts of stand management on ponderosa pine physiology and bark beetle abundance in northern arizona: a replicated landscape study. For Ecol Manag 218:291–305CrossRefGoogle Scholar
  40. Zhang Y, Reed D, Cattelino P, Gale M, Jones E, Liechty H, Mroz G (1994) A process-based growth model for young red pine. For Ecol Manag 69:21–40CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  1. 1.Department of Biological SciencesUniversity of AlbertaEdmontonCanada
  2. 2.Department of Mathematical and Statistical SciencesUniversity of AlbertaEdmontonCanada
  3. 3.Department of BiologyQueen’s UniversityKingstonCanada

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