SIREX NOCTILIO HOST CHOICE AND NO-CHOICE BIOASSAYS: WOODWASP PREFERENCES FOR SOUTHEASTERN U.S. PINES by JAMIE ELLEN DINKINS (Under the Direction of Kamal J.K. Gandhi) ABSTRACT Sirex noctilio F., the European woodwasp, is an exotic invasive pest newly introduced to the northeastern U.S. This woodwasp kills trees in the Pinus genus and could potentially cause millions of dollars of damage in the southeastern U.S., where pine plantations are extensive. At present, little is known about the preferences of this wasp for southeastern pine species, and further, little methodology exists as related to conducting host choice or no-choice bioassays with this species. My thesis developed methodology to successfully perform S. noctilio host choice and no-choice bioassays (both colonization and emergence from bolts), examined S. noctilio behavioral and developmental responses to southeastern U.S. pine species using bolts, and investigated possible mechanisms to explain these behavioral responses. Results indicated larger bolts were preferred to smaller bolts by S. noctilio, and P. strobus and P. virginiana were preferred out of six southeastern species in host choice bioassays. KEYWORDS: choice and no-choice bioassay, southeastern pines, European woodwasp, host preference, mechanisms, Sirex noctilio, Pinus SIREX NOCTILIO HOST CHOICE AND NO-CHOICE BIOASSAYS: WOODWASP PREFERENCES FOR SOUTHEASTERN U.S. PINES by JAMIE ELLEN DINKINS B.S. The University of Tennessee at Chattanooga, 2009 A Thesis Submitted to the Graduate Faculty of the University of Georgia in Partial Fulfillment of the Requirements for the Degree MASTER OF SCIENCE Athens, GA 2011 © 2011 Jamie Ellen Dinkins All Rights Reserved SIREX NOCTILIO HOST CHOICE AND NO-CHOICE BIOASSAYS: WOODWASP PREFERENCES FOR SOUTHEASTERN U.S. PINES By Jamie Ellen Dinkins Major Professor: Kamal J.K. Gandhi Committee: Jeffrey F. D. Dean John J. Riggins Laurie R. Schimleck Electronic Version Approved: Maureen Grasso Dean of the Graduate School The University of Georgia December 2011 ACKNOWLEDGEMENTS I would like to thank my parents for giving me both the monetary and the emotional support to follow my dreams, and Kamal Gandhi, my advisor, for providing the opportunity and wonderful guidance that enabled me to continue to pursue my goals. Thanks also to my committee members Laurie Schimleck, John Riggins, and Jeffrey Dean, who so graciously volunteered their time. My lab-mates and friends Brittany Barnes, Kayla Brownell, Jordan Burke, Angela Mech, and Jenny Staeben all contributed dry humor and much needed helping hands. Lee Ogden and Dale Porterfield were also vital to my success. Joey Shaw and Hill Craddock (University of Tennessee, Chattanooga) were integral mentors. Other people that provide critical support, laboratory and/or field work include: J. Audley, (University of Georgia, Athens); E. Andrews, B. Sullivan, K.J. Dodds, J.L. Hanula, P. Hopton, S. Horn, and J.W. Taylor (USDA Forest Service); J. Johnson, E. Mosley, and T. Page (Georgia Forestry Commission); V. Mastro and K. Zylstra (USDA- APHIS); M. Fierke, R. Fencl, and C. Standley (SUNY-ESF); and P. deGroot (deceased, Canadian Forest Service). F. Anthony, Y. Chen, R. Gianini, and J. Reeves (UGA) provided statistical guidance. Funding for this project was provided by the Special Technology Development Team (STDP), Forest Health Protection, USDA Forest Service, and state funds provided by the D.B. Warnell School of Forestry at the University of Georgia. iv Finally, I would like to thank my best friend and fiancé, Brent Bookwalter, who has dealt smoothly with the flood of stress with which I often sweep over our house. His love and patience has been a pillar of support in my life. v TABLE OF CONTENTS Page ACKNOWLEDGEMENTS........................................................................................................iv LIST OF TABLES.....................................................................................................................ix LIST OF FIGURES ....................................................................................................................x CHAPTER 1 INTRODUCTION AND LITERATURE REVIEW ...................................................1 ALIEN INVASIVE SPECIES: ENVIRONMENTAL AND ECONOMIC DAMAGE............................................................................................................1 ALIEN INVASIVE SAPROXYLIC FOREST INSECTS.....................................2 CASE-STUDY OF AN EXOTIC XYLOPHAGOUS INSECT: SIREX NOCTILIO F........................................................................................................4 RISK OF SIREX NOCTILIO TO NORTH AMERICAN FORESTS.....................6 RISK OF SIREX NOCTILIO TO SOUTHEASTERN U.S. FOREST STANDS .............................................................................................................8 HOST PREFERENCES OF SIREX NOCTILIO....................................................9 CURRENT RISK ASSESSMENT MAPS OF SIREX NOCTILIO ......................12 CONCLUSION..................................................................................................12 REFERENCES ..................................................................................................15 vi 2 BEHAVIORAL AND COLONIZATION PREFERENCES OF THE EUROPEAN WOODWASP, SIREX NOCTILIO F. (HYMENOPTERA: SIRICIDAE), FOR TWO SOUTHEASTERN U.S. PINES (PINUS SPP.) SPECIES .................................................................................................................27 ABSTRACT ......................................................................................................28 KEYWORDS.....................................................................................................29 INTRODUCTION .............................................................................................29 METHODS........................................................................................................32 RESULTS..........................................................................................................38 DISCUSSION....................................................................................................41 ACKNOWLEDGMENTS..................................................................................45 REFERENCES ..................................................................................................46 TABLES............................................................................................................52 FIGURE LEGEND ............................................................................................53 3 HOST PREFERENCE AND PREFERENCE MECHANISMS OF SIREX NOCTILIO F. FOR SIX SOUTHEASTERN U.S. PINE SPECIES IN NORTH AMERICA ..............................................................................................................58 ABSTRACT ......................................................................................................59 KEYWORDS.....................................................................................................60 INTRODUCTION .............................................................................................60 METHODS........................................................................................................66 RESULTS..........................................................................................................75 DISCUSSION....................................................................................................82 vii ACKNOWLEDGMENTS..................................................................................90 REFERENCES ..................................................................................................91 TABLES..........................................................................................................103 FIGURE LEGEND ..........................................................................................110 4 THESIS CONCLUSIONS .....................................................................................116 DIRECTIONS FOR FURTURE RESEACH....................................................118 REFERENCES ................................................................................................121 APPENDICES A POISSON DISTRIBUTION ..................................................................................123 B KRUSKAL-WALLIS TEST STATISTIC, H.........................................................124 C DUNN’S TEST .....................................................................................................125 viii LIST OF TABLES Page Table 2.1: Size of bolts used in host choice and no-choice bioassays on Sirex ...........................50 Table 2.2: Mean (± SE) counts of progeny and exit holes of Sirex noctilio on only large pine bolts (18 to 26 cm diameter) in host choice experiments.........................................52 Table 3.1: Bioassay type, pine species, location of trees, dates that trees were cut, and mean diameter at breast height of trees used in host choice and no-choice bioassays on Sirex noctilio...........................................................................................103 Table 3.2: Means (± SE) of surface area, age, radial strip specific gravity, first ten-ring specific gravity, and resin canal density and size among seven species of pines (n = 3)..............................................................................................................................105 Table 3.3: