In 1984, a new research working party on mechanismsofwoody plant resistance against insects and pathogens(lUFROS2. 05-06) was formed in the International Union ofForestryResearchOrganizations. Thepurposeofthisworkingparty istostimulate and facilitate research progress in this areathroughenhancedcommunication among themany researchscientistsscatteredamongthevariouscountriesoftheworld. This volume istheresultofthe first internationalsymposiumofthisworkingparty, which took place in Orleans. France on August 26-29, 1986. Thanks are due to Institute Nationalde laRechercheAgronomique, StationdeZoologie, Forestiere, fortheir in strumental part in organizingthis symposium, and to the University and the Cityof Orleansforgenerousfinancial support. The intentofthis proceedings is to (a) bring together adiverse array ofresearch resultsonthemechanismsofwoodyplantresistanceagainstdifferentkindsofinsects. and(b) to search for threadsofcommonality among these different plant/insect as sociationstofurtherourfundamental understandingofhowplantsdefendthemselves againstphytophagousorganisms. Theresearchpapersareorganizedintothreemaingroups. Thefirstgroupexamines plant defenses from various basic physiological and ecological considerations. The remaining papers, which are mainly case studiesofplant resistance against insects. arecategorizedon the basisofinsect intimacy with host tissues: (a) highly mobile. free feeders suchas moth larvae andsawflies, and (b)poorlymobile, "attached" or imbeddedfeederssuchasaphids, scales, miners, andbarkbeetles. Eachofthesesections isfurtherorganizedonthebasisofkindoftissueattackedbytheinsects, eitherleaves orstern/shootcortexand vasculartissues. Contents Preface v Contributors IX I. Basic Physiological and Ecological Considerations I. DefensiveStrategiesofWoody PlantsAgainst Different Insect-Feeding Guilds in Relation to Plant Ecological Strategiesand IntimacyofAssociation with Insects W. J. Mattson. R. K. Lawrence, R. A. Haack, D. A. Herms, and p. J. Charles 3 2. Towards a UnifiedTheoryofPlant Defense A. A. Berryman. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3lJ 3. DefensiveResponsesofTrees inRelationtoTheirCarbon/NutrientBalance J. Tuomi, P. Niemela, F. S. Chapin,1II, J. P. Bryant, andS. Siren 57 4. GrowthandDifferentiation.BalanceRelationshipsinPinesAffectTheirRe. sistance to Bark Beetles(Coleoptera: Scolytidae) P. L. Lorio, Jr. 73 5. SeasonalVariations inEnergySourcesandBiosynthesisofTerpenes in Maritime Pine C. Bernard-Dagan 93 6. Terpene Biosynthesis Under PathologicalConditions C. Cheniclet, C. Bernard-Dagan, andG."

This publication explores many facets of the ever intriguing and enigmatic relationships between plants and their gall-forming herbivores. The research reported herein ranges from studies on classical biology and systematics of galling to molecular phylogeny, population genetics, and ecological and evolutionary theory. Human kind has much to learn and gain from understanding the fine details of how plants and their gallers interact. This publication is the result of an international symposium that was held August, 1997 in Hungary. It was organized under the guidelines of the International Union of Forestry Research Organizations by the Hungarian Forest Research Institute, Department of Forest Protection, and the North Central Research Station of the US Forest Service.