Age-specific life table studies of potential strains or host races of Calophasia lunula (Lepidoptera: Noctuidae) (Hufn.) reared on Dalmation toadflax, Linaria genistifolia ssp. dalmatica (L.) Maire and Petitmengen, or yellow toadflax, Linaria vulgaris (Mill.) by Todd Alan Breitenfeldt A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Entomology Montana State University © Copyright by Todd Alan Breitenfeldt (1995) Abstract: Although the possible existence of host races in phytophagous biological control agents has only recently come under general consideration when screening and releasing these agents, the implications for successful establishment and impact on the target weed, and for minimizing impacts on nontarget plant species are enormous. The issues of potential host races and strain differences were investigated for different populations of the defoliating moth, Caloohasia lunula, which attacks Dalmatian toadflax, Linaria genistifolia ssp. dalmatica (L.) Maire and Petitmengen, and yellow toadflax, Linaria vulgaris (Mill'.), using age-specific life table studies. Life table studies of the three Calophasia populations (one obtained from Europe on Yellow toadflax, another obtained from yellow toadflax in Europe and established on Dalmatian toadflax in Montana, and the third obtained from Dalmatian toadflax from Yugoslavia) were tested on both Dalmatian toadflax and yellow toadflax. Little evidence of host races was evident. Caloohasia lunula rates of development and weight gain, survivorship, and fecundity occurred at the same rate or pattern on both plants of interest. This supports the previous starch gel electrophoretic studies by McDermott and Nowierski (unpub. data). Some strain differences were apparent. Analysis of life table data showed significant difference in mean duration of life stages between strains, mean weight between strains, and differences in lower developmental thresholds, intrinsic rates of increase (rm), population doubling times (PDT), mean generation times (MGT), and net reproductive rates (Ro) . Little evidence of strain differences were found in the analysis of survivorship, fecundity, mean rates of development, and mean rates of weight gain. It is probable that strains of C. lunula exist, but more research needs to be conducted to further clarify these relationships. Strategies for mass rearing C. lunula and improving the chances for establishment on Dalmatian toadflax are discussed. AGE-SPECIFIC LIFE TABLE STUDIES OF POTENTIAL STRAINS OR HOST RACES OF CALOPHASIA LUNULA (LEPIDOPTERA: NOCTUIDAE)(HUFN.) REARED ON DALMATIAN TOADFLAX, LINARIA GENISTIFOLIA SSP. DALMATICA (L.) MAIRE AND PETITMENGEN, OR YELLOW TOADFLAX, LINARIA VULGARIS (MILL.) ' by Todd Alan Breitenfeldt A thesis submitted in partial fulfillment of the requirements for the degree ' Of Master of Science ' in Entomology MONTANA STATE UNIVERSITY-BOZEMAN Bozeman, Montana August, 1995 A/3'1? S>W4~ ii APPROVAL of a thesis submitted by Todd Alan Breitenfeldt This thesis has been read by each member of the thesis committee and has been found to be satisfactory regarding content, English usage, format, citations, bibliographic style, and consistency, and is ready for submission to the College of Graduate Studies. q./C'fsr Date Chairperson,Graduate Committee Approved for the Major Department Approved for the College of Graduate Studies T/yz/)r^ Graduate Dean iii STATEMENT OF PERMISSION TO USE In presenting this thesis in partial fulfillment of the requirements for a master's degree at Montana State University-Bozeman, I agree that the Library shall make it available to the borrower under rules of the Library. If I have indicated my intention to copyright this thesis by including a copyright notice page, copying is allowable only for scholarly purposes, consistent with "fair use as prescribed in the U .S. Copyright Law. Requests for permission for.extended quotation from or reproduction of this thesis in whole or in parts may be granted only by the Date V ACKNOWLEDGMENTS I express my heartfelt and sincere thanks to my advisor, Bob Nowierski for his helpful and patient guidance during this project. Thanks is also extended to Kevin O'Neill, Jeffrey Littlefield and Robert Moore for their advice, help and support concerning this project. This study could not have been conducted without the Canadian strains of Caloohasia lunula provided by Alec McClay and Peter Harris, Agriculture Canada, and Mike Sarazin, Bio Systamatics Research Center, Ottowa, Canada. My thank you also goes to the Entomology department and staff, and to my fellow graduate students and lab assistants. Because I am first a busy teacher of high school science students, I had only a narrow window of time each summer to complete my lab projects and write this thesis. Some of these spilled over into a time when I could not be there to take data or clean up my mess. The following people helped during these times; Bryan Fitzgerald, Greg McDermott, Lance Adams, Joe Bunnell, Bob Grubb, Steve Rearing, and finally Zheng Zeng for his invaluable help in speeding the statistical analysis involved with this thesis. vi TABLE OF CONTENTS Page APPROVAL. ..............................................ii STATEMENT OF PERMISSION TO USE.......... .............. iii VITA. ..............................■.................. iv ACKNOWLEDGMENTS.... ■............. .......................V TABLE OF CONTENTS..................... ...............,. vi LIST OF TABLES............................ :......... viii LIST OF FIGURES. ............. ..........................X GLOSSARY OF TERMS....,........................ -......... xi ABSTRACT..................................... xiii CHAPTERS: 1. Introduction: A Description of the Toadflax Weed Problem...................................... I . I 2. Biology and History of L. dalmatica..... .............I 3. Biology and History of L. vulgaris Toadflax...... ................... ..................12 4. Biology and History of Calophasia lunula ........... 15 A History of North American Releases.... .......... 24 5. Strains and Host Races........... .................. 31 6. Materials and Methods............................... 3 5 Parameters measured in study.........:............41 7. Age-Specific Life-Table/Data Analysis. ............... 43 Results............................ .............* . 44 Mean Duration of Life-Stages Between Strains..44 vii TABLE OF CONTENTS— Continued Page Mean Duration of Life-Stages Between Plants... 49 Mean Weights Between Strains................. 53 Mean Weights Between Plants.................. 56 Survivorship. ................................ 61 Fecundity. ............................ 65 Larval Rates of Weight Gains................. 70 Mean Rates of Development.................... 74 Lower Developmental Thresholds............... 75 Life-Table Statistics........................ 79 8. Discussion.......................................... 81 9. Conclusions...................... 86 REFERENCES CITED.................................. 88 APPENDIX: Caloohasia lunula Mass Rearing Techniques used at MSU............................ 94 viii LIST OF TABLES Table Page I. Historic United States releases of Caloohasia lunula against L. g. dalmatica. and imports........ 25 2. C. lunula releases from MSU............... :........28 3. Number of Calophasia lunula eggs used for each cohort............................................. 3 5 4. Mineral content of L. dalmatica and L. vulgaris food plants used................................... 41 5. Mean duration in days of life stages of three strains of Calophasia lunula reared on L. g. dalmatica or L. vulgaris at 16° C ............................... 45 6. Mean duration in days of life stages of three strains of Caloohasia lunula reared on L. g. dalmatica or L. vulgaris at 2O0C ........ .... 46 7. Mean duration in days of life stages of three strains of Caloohasia lunula reared on L. g. dalmatica or L. vulgaris at 2S0C ............. 47 8. Mean duration in days of life stages of three strains of Caloohasia lunula reared on L. g. dalmatica or L. vulgaris at 32° C .................. 48 9. Mean duration in days of life-stages within MD strain of Caloohasia lunula compared by plant, L. g. dalmatica and L. vulgaris.................... 50 10. Mean duration in days of life-stages within CD strain of Caloohasia lunula compared by plant, L. g. dalmatica and L. vulgaris.................... 51 11. Mean duration in days of life-stages within CY strain of Caloohasia lunula compared by plant, L. g. dalmatica and L. vulgaris ................... 52 12. Mean weights of life stages of three strains of Caloohasia lunula reared on L. g. dalmatica or L. vulgaris at 16° C.................................. 53 ix" LIST OF TABLES— Continued 13. Mean weights of life stages of three strains of Caloohasia lunula- reared on L. g. dalmatica or L. vulgaris toadflax at 20°.C ................ .........54 14. Mean weights of life stages of three strains of Calophasia lunula reared on L. g. dalmatica or L. vulgaris at 28° C .................................. 55 15. Mean weights of life stages of three strains of Caloohasia lunula reared on L. dalmatica or L. vulgaris at 32° C....... '.......... -............... 56 16. Mean weight comparisons within MD strain of Caloohasia lunula compared by plant, L. g. dalmatica and L. vulgaris.................................... 58 17. Mean weight comparisons within CD strain of Caloohasia lunula compared by plant, L. g. dalmatica and L. vulgaris......................