DISPERSAL AND FLIGHT BEHAVIOR OF TRYPODENDRON LINEATUM (OLIVIER) (COLEOPTERA: SCOLYTIDAE) AS INFLUENCED BY SEMIOCHEMICAL AND ENVIRONMENTAL FACTORS By SCOTT MICHAEL SALOM B.S., Iowa State University, 1981 M.S., University of Arkansas, 1985 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE STUDIES (Department of Forest Sciences) We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA April 7, 1989 © Scott Michael Salom, 1989 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of The University of British Columbia Vancouver, Canada Date DE-6 (2/88) ii ABSTRACT Laboratory bioassays using a wind tunnel were developed to study flight behavior and orientation of the striped ambrosia beetle, Trvpodendron lineatum (Olivier). Factors that were studied in detail were windspeed, semiochemical concentrations, and semiochemical combinations. In the first of two experiments examining the effect of wind speed on T. lineatum response to a semiochemical-baited substrate, the highest % of males (21.4) and females (25.3) caught in a funnel trap, occurred at 0.0 m/s. As windspeed was increased from 0.0 to 0.9 m/s, the percent of beetles caught decreased linearly for both sexes. A second experiment showed that in the presence of wind, responding beetles oriented anemotactically to the semiochemical-baited substrate. With wind absent, beetles flew randomly and erratically. Upon reaching close to the baited substrate, a greater proportion of the beetles responded to the chemical stimuli and landed on the substrate than when an airflow was present. These results suggest that T. lineatum are capable of responding under varied wind conditions typically present in a forest, whereby they use wind to orient to olfactory stimuli, yet are best arrested to the stimuli under still conditions. Flight response of T. lineatum to a multiple funnel trap baited with ethanol (1° attractant) and lineatin (2° attractant) at different release rates, indicated that only lineatin was effective in attracting beetles to this kind of trap. Maximum response by both males and females occurred at release rates of lineatin between 8 and 64 ug/24 h. However, in a more detailed study of T. lineatum response to ethanol and lineatin using modified drainpipe traps, serving as a model of a host tree, ethanol did positively influence male flight type, speed of reaction, and direction. Nevertheless, lineatin was the most important semiochemical in attracting males to land on and enter the traps. Ethanol was more important for females than for males, and when combined with lineatin, provided the optimal stimuli for attracting females to land on and enter the traps. Population movement of spring dispersing T. lineatum was studied using mark-recapture techniques with lineatin- baited funnel traps. In a first set of studies conducted in an even-aged second-growth coastal forest in British Columbia, beetle recapture distribution was compared with wind direction at distances between 5 and 500 m from the beetle release site. At 5 and 25 m, beetle recapture was predominantly upwind. With traps placed only at 100 m from the release site, beetles were recaptured in all directions irrespective of wind. However, with traps placed only 500 m from the release site, beetles were only recaptured in the downwind traps. In mark-recapture experiments conducted in a valley, beetles released from a forest margin influenced by prevailing up-valley winds, flew upwind within the forest to iv lineatin-baited funnel traps placed 25 m from the release site. Beetle recapture in an open setting was higher along the edge of the open setting than in its center, 325 m closer to the release site. Beetles were recaptured 1 km down-valley (upwind) and 1.9 km up-valley (downwind) from the release site. In one experiment (two releases), 10.6 and 7.8% of the marked beetles recaptured were collected in traplines > 700 m and > 1 km from the release site, respectively. In additional mark-recapture experiments in the valley, beetles were released simultaneously from a windward and leeward side of a forest margin in the valley through two experiments of four releases each. With long distance flight emphasized and no semiochemical-baited traps placed within 200 m of either release site, population movement was predominantly downwind. Beetles also flew across the valley to traps on the opposite facing slope at a fairly high frequency (38% of the recaptured beetles), during the first experiment. Beetles were recaptured at a much higher frequency in traps placed within a forest as compared to those in an open setting. This was likely a result of the calmer wind conditions under the forest canopy, facilitating better flying conditions and response to olfactory stimuli for the beetles. The implications these findings have on the general knowledge of scolytid beetle dispersal and orientation to olfactory stimuli are discussed. New considerations toward V improving pest management strategies for T. lineatum as a result of these sets of studies are presented. yi TABLE OF CONTENTS Page ABSTRACT ii TABLE OF CONTENTS vi LIST OF TABLES ix LIST OF FIGURES xii ACKNOWLE DGEMENTS xv i i i CHAPTER 1: OVERVIEW 1 1.1 Introduction 1 1.2 Objectives 7 1.3 Format 10 CHAPTER 2: THE EFFECT OF WIND SPEED ON TRYPODENDRON LINEATUM FLIGHT BEHAVIOR IN A WIND TUNNEL 12 2.1 Introduction 12 2.2 Materials and Methods 14 2.3 Results 21 2.4 Discussion 32 CHAPTER 3: RESPONSE OF TRYPODENDRON LINEATUM TO VARIED RELEASE RATES OF ETHANOL AND LINEATIN IN A WIND TUNNEL 39 3.1 Introduction 39 3.2 Materials and Methods 41 3.3 Results 44 3.4 Discussion 46 CHAPTER 4: WIND TUNNEL EVALUATION OF FLIGHT AND LANDING BEHAVIOR OF TRYPODENDRON LINEATUM (OLIVIER) IN RESPONSE TO A HOST ATTRACTANT AND AGGREGATION PHEROMONE 49 4.1 Introduction 49 vii 4.2 Materials and Methods 51 4.3 Results 56 4.4 Discussion 69 CHAPTER 5: INFLUENCE OF WIND ON THE SPRING FLIGHT OF TRYPODENDRON LINEATUM IN A SECOND- GROWTH CONIFEROUS FOREST 74 5.1 Introduction 74 5.2 Materials and Methods 75 5.3 Results and Discussion 82 CHAPTER 6: DISPERSAL OF TRYPODENDRON LINEATUM (OLIVIER) WITHIN A VALLEY SETTING 96 6.1 Introduction 96 6.2 Materials and Methods 97 6.3 Results and Discussion 106 CHAPTER 7: POPULATION MOVEMENT PATTERNS OF TRYPODENDRON LINEATUM AS INFLUENCED BY WIND AND VEGETATION WITHIN A VALLEY 12 9 7.1 Introduction 129 7.2 Materials and Methods 13 0 7.3 Results and Discussion 139 CHAPTER 8: CONCLUSIONS 161 REFERENCES 170 APPENDIX 1: RESPONSE OF TRYPODENDRON LINEATUM (OLIVIER) TO DIFFERENT SEMIOCHEMICAL- BAITED SUBSTRATES IN A WIND TUNNEL 181 APPENDIX 2: RESPONSE OF FLOWN AND UNFLOWN T. LINEATUM TO SEMIOCHEMICAL-BAITED FUNNEL TRAPS IN A WIND TUNNEL 184 A. 2.1 Introduction 184 A.2.2 Materials and Methods 185 A.2.3 Results and Discussion 189 APPENDIX 3: INFLUENCE OF DUSTING T. LINEATUM WITH viii FLUORESCENT POWDER ON THEIR RESPONSE TO SEMIOCHEMICALS IN A WIND TUNNEL 193 ix LIST OF TABLES Page Table 1. Frequency of Trypodendron lineatum flight in a wind tunnel at varied wind speeds in the presence of an unbaited and semiochemical-baited simulated log 24 Table 2 Statistical comparison of T. lineatum responses to first and second year control treatments in a wind tunnel. The numbers of the beetles released for each sex/ treatment = 124 57 Table 3. Flight frequency of T. lineatum to different semiochemical baits in a wind tunnel. Number of beetles released for each sex in each bait treatment = 124. 58 Table 4. The capture of T. lineatum in semiochemical-baited drainpipe traps in a wind tunnel (N = 124 released/treatment/ sex) 68 Table 5, Numbers of marked T. lineatum released and recaptured in the flight direction study on the University Endowment Lands, Vancouver, B.C., 1986 84 Table 6, Relationship of flight direction of T. lineatum to the wind direction, using a one-sample test for the mean directional flight angle on the University Endowment Lands, Vancouver, B.C., 1986 87 Table 7, Percent of T. lineatum caught at varied distances in the mark-recapture study, experiments 1 and 2, University Endowment Lands, Vancouver, B.C., 1986 90 Table 8. Comparison of wind direction and speed between forested and open sites within the Cedar Creek Valley (up-valley azimuth of 48 to 68°) in the Coquitlam Lake Watershed B.C., 1987 108 Table 9. Flight and recapture success of T. lineatum in the mark-recapture study at the Coquitlam Lake Watershed, B.C., 1987 (Day 1 and Day 2 data were pooled). 110 Table 10. The number of marked T. lineatum recaptured with respect to time in a X dense old growth forest in the Coquitlam Lake Watershed, B.C., 1987 Ill Table 11, Mean percent of T. lineatum recaptured at varied distances in the Cedar Creek Valley, Coquitlam Lake Watershed, B.C., 1987 , 113 Table 12 Comparison of T. lineatum flight and wind direction in an old growth forest in the Coquitlam Lake Watershed, B.C., 1987 114 Table 13 Weather measurements made between 113 0 and 1700 h PDT, from the Cedar Creek Valley in the Coquitlam Lake Watershed in British Columbia during 1988 141 Table 14, Flight and recapture success of Trypodendron lineatum in the mark- recapture study conducted at the Coquitlam Lake Watershed in British Columbia during 1988 148 Table 15, Comparison between up- and down-valley movement of adult Trypodendron lineatum during the mark-recapture study conducted in the Cedar Creek Valley within the Coquitlam Lake Watershed in British Columbia during 1988 150 Table 16, Movement of T.