Forest Health Technology Enterprise Team TECHNOLOGY TRANSFER Biological Control ASSESSING HOST RANGES FOR PARASITOIDS AND PREDATORS USED FOR CLASSICAL BIOLOGICAL CONTROL: A GUIDE TO BEST PRACTICE R. G. Van Driesche, T. Murray, and R. Reardon (Eds.) Forest Health Technology Enterprise Team—Morgantown, West Virginia United States Forest FHTET-2004-03 Department of Service September 2004 Agriculture he Forest Health Technology Enterprise Team (FHTET) was created in 1995 Tby the Deputy Chief for State and Private Forestry, USDA, Forest Service, to develop and deliver technologies to protect and improve the health of American forests. This book was published by FHTET as part of the technology transfer series. http://www.fs.fed.us/foresthealth/technology/ Cover photo: Syngaster lepidus Brullè—Timothy Paine, University of California, Riverside. 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ASSESSING HOST RANGES OF PARASITOIDS AND PREDATORS USED FOR CLASSICAL BIOLOGICAL CONTROL: A GUIDE TO BEST PRACTICE R.G. Van Driesche and R. Reardon, Editors This publication is also available electronically through www.invasive.org. For additional copies of this publication, contact: Richard Reardon FHTET, USDA Forest Service 180 Canfield Street Morgantown, West Virginia 26505 (304) 285-1566 [email protected] Photographs used in this publication can be accessed online through reference codes (UGA0000000) in the captions for the figures. To load an image, point your browser at www.forestryimages.org, and enter the reference code at the search prompt. ___________________________________ Assessing Host Ranges of Parasitoids and Predators Contents Chapter 1. Introduction: Predicting Host Ranges of Parasitoids and Predacious Insects— What are the Issues? (by R. G. Van Driesche) .................................................................... 1 Chapter 2. The Effects of Compsilura concinnata, an Introduced Generalist Tachinid, on Non-target Species in North America: A Cautionary Tale (by J. S. Elkington and G. H. Boettner) ....................................................................................................................... 4 Chapter 3. Using the Scientific Literature to Estimate the Host Range of a Biological Control Agent (by D. P. A. Sands and R. G. Van Driesche) ............................................................. 15 Chapter 4. Analysis of Fauna in the Receiving Area for the Purpose of Identifying Native Species that Exotic Natural Enemies May Potentially Attack (by M. S. Hoddle) ................................................................................................................ 24 Chapter 5. Behavioral and Physiological Processes Affecting Outcomes of Host Range Testing (by T. M. Withers and L. B. Browne) ...................................................................... 40 Chapter 6. Parameters Used in Laboratory Host Range Tests (by R. G. Van Driesche and T. J. Murray) ........................................................................................................................ 56 Chapter 7. Overview of Testing Schemes and Designs Used to Estimate Host Ranges (by R. G. Van Driesche and T. J. Murray) ............................................................................. 68 Chapter 8. Estimating the Host Range of a Thrips Parasitoid (by K. J. Froud and P. S. Stevens) .. 90 Chapter 9. Microctonus Parasitoids and New Zealand Weevils: Comparing Laboratory Estimates of Host Ranges to Realized Host Ranges (by B. I. P. Barratt)................... 103 Chapter 10. Evaluation of Lily Leaf Beetle Parasitoids for North American Introduction (by R. A. Casagrande and M. Kenis) ................................................................................ 121 Chapter 11. Host Preference Testing for Parasitoids of a Eucalyptus Borer in California (by T. D. Paine, J. G. Millar, and L. M. Hanks)................................................................ 138 Chapter 12. Estimating the Host Range of the Tachinid Trichopoda giacomellii, Introduced into Australia for Biological Control of the Green Vegetable Bug (by M. Coombs) .............................................................................................................. 143 Chapter 13. Assessing Host Specificity and Field Release Potential of Fire Ant Decapitating Flies (by S. D. Porter and L. E. Gilbert)........................................................................... 152 Chapter 14. Determining the Host Range of Aphantorhaphopsis samarensis, a Specialized Tachinid Introduced Against the Gypsy Moth (by R. W. Fuester, K. S. Swan, M. Kenis, and F. Hérard) ................................................................................................. 177 Chapter 15. Predicting the Field Prey Range of an Introduced Predator, Rodolia cardinalis Mulsant, in the Galápagos (by C. E. Causton) .......................................................... 195 Chapter 16. Evaluating Host Range of Laricobius nigrinus for Introduction into the Eastern United States for Biological Control of Hemlock Woolly Adelgid (by G. Zilahi- Balogh) ........................................................................................................................... 224 Chapter 17. Conclusions (by R. G. Van Driesche)........................................................................... 239 iii ____________________________________ ASSESSING HOST RANGES OF PARASITOIDS AND PREDATORS CHAPTER 1. INTRODUCTION PREDICTING HOST RANGES OF PARASITOIDS AND PREDACIOUS INSECTS—WHAT ARE THE ISSUES? R. G. Van Driesche Department of Plant, Soil and Insect Science: Division of Entomology, University of Massachusetts, Amherst, MA 01003 USA [email protected] GOALS FOR HOST RANGE TESTING Estimating the likely nontarget impacts of agents released to suppress invasive plants has been legally required, to one degree or another, for many decades. Similar predictions were not formally required for introductions of parasitoids or predators of pest arthropods. That is now beginning to change. This book has as its goal an exploration of how such estimates can best be made. This requires overcoming a series of problems, some logistical, some technical, some tied to an unclear theoretical framework for the activity. In this book, the editors and authors have tried to address many of these needs, in some chapters as essays on important tasks that need to be achieved, in other chapters as case history explorations of how the tasks were done in particular cases. This book will not be the fi nal answer, but we hope it might propel the search for such an answer along. LEGAL REQUIREMENTS Whether or not predicting the host ranges of parasitoids and predators is legally required var- ies among countries. There is an absolute requirement for such predictions in New Zealand and Australia, but not in most other countries. In the EU, there is a developing consensus that such information will be required, but in the United States legal authority is lacking to impose such a requirement. Rather, the degree of such an assessment currently depends on the agency of employment of the person importing the natural enemy, with more stringent requirements for federal employees. Chapter 1. Introduction 1 ASSESSING HOST RANGES OF PARASITOIDS AND PREDATORS ___________________________________ Regardless of the current legal status quo in any particular country, there is a trend to impose such requirements. The role of this book is in part to shape how such requirements are written, by revealing some of the complexities in the process of making such estimates and highlighting the risks of making overly sweeping assumptions about the utility of laboratory test data. PRACTICAL PROBLEMS Some of the problems posed by estimating the host ranges of candidate entomophagous biocontrol agents relative to the fauna of the receiving country are purely practical, rather than theoretical. Compared to plants, the number of species in a native biota of insects can be overwhelmingly large, with hundreds, thousands, even tens of thousands of native species in the target pest’s family in the receiving biogeographic region. Many of these are likely to have little or no information associated with museum specimens about such important matters as their biology, habitat, host plants, and so on. This double edged problem, too many species and too little information, can cripple efforts to rationally consider the impact of a new para- sitoid or predator on such a group. Many species that would be desirable members of a host range test list may be impossible to fi nd or, if found, information on how to rear them will be unavailable. Rearing diffi