University of Massachusetts Amherst ScholarWorks@UMass Amherst Doctoral Dissertations 1896 - February 2014 1-1-1984 Studies on vision and visual attraction of the salt marsh horse fly, Tabanus nigrovittatus Macquart. Sandra Anne Allan University of Massachusetts Amherst Follow this and additional works at: https://scholarworks.umass.edu/dissertations_1 Recommended Citation Allan, Sandra Anne, "Studies on vision and visual attraction of the salt marsh horse fly, Tabanus nigrovittatus Macquart." (1984). Doctoral Dissertations 1896 - February 2014. 5625. https://scholarworks.umass.edu/dissertations_1/5625 This Open Access Dissertation is brought to you for free and open access by ScholarWorks@UMass Amherst. It has been accepted for inclusion in Doctoral Dissertations 1896 - February 2014 by an authorized administrator of ScholarWorks@UMass Amherst. For more information, please contact [email protected]. STUDIES ON VISION AND VISUAL ATTRACTION OF THE SALT MARSH HORSE FLY, TABANUS NIGROVITTATUS MACQUART A Dissertation Presented By SANDRA ANNE ALLAN Submittted to the Graduate School of the University of Massachusetts in partial fulfillment of the requirements of the degree of DOCTOR OF PHILOSOPHY February 1984 Department of Entomology *> Sandra Anne Allan All Rights Reserved ii STUDIES ON VISION AND VISUAL ATTRACTION OF THE SALT MARSH HORSE FLY, TABANUS NIGROVITTATUS MACQUART A Dissertation Presented By SANDRA ANNE ALLAN Approved as to style and content by: iii DEDICATION In memory of my grandparents who have provided inspiration ACKNOWLEDGEMENTS I wish to express my most sincere appreciation to my advisor. Dr. John G. Stoffolano, Jr. for his guidance, constructive criticism and suggestions. I would also like to thank him for allowing me to pursue my research with a great deal of independence which has allowed me to develop as a scientist and as a person. I would particularly like to thank Dr. Ruth Bennett for her generosity, encouragement and enthusiasm which has opened the door of insect vision for me. I express gratitude to Dr. John Edman and Dr. Joe Elkinton for their critical reading of the manuscripts, helpful suggestions and interest during this project. Myvappreciation is also extended to the entire faculty for giving me the opportunity. I would also like to express ray appreciation to Dr. Gary Bernard and Dr. Dick White for their interest and suggestions during this project. I extend deep appreciation to Dr. Beth Owens for discussions and suggestions on insect vision, encouragement, and, not least of all, her friendship. My sincere appreciation is extended to my summer assistants, Juliet Tang and Roberta Greenberg, whose unending enthusism, energy, patience and limitless good humor are a reason for the success of this project• A debt of gratitude goes to Dr. Herb Hultin for allowing me use of the facilities at the University of Massachusetts Marine Station at v Gloucester I also wish to thank Dr. Chris Martin and others at the Marine Station for their generosity during the summers. My thanks goes to Larry Urlich, Norm Dobson, and Bob Spencer of the Essex County Mosquito Control Association for their enthusiasm and generous assistance for the duration of this project. I would also like to extend appreciation to Station Service for their assistance and hospitality over the years. t I appreciate the support, interest and encouragement of friends and graduate students in the Department of Entomology. They have helped me maintain perspective on life. Words can not express my gratitude to my parents whose patience and faith in me provided inspiration itself. And, of course, my deepest appreciation is extended to Chris \ Geden for his support, encouragement and equanimity during my years through the rites of this degree. This project was supported by a grant from the Massachusetts Experiment Station (Mclntire Stennis Project 30) to Dr. John G. Stoffolano, Jr. ABSTRACT Studies on vision and visual orientation of the salt marsh horse fly, Tabanus nigrovittatus Macquart (February 1984) Sandra Anne Allan, B.Sc., University of Guelph M.Sc., University of Guelph, Ph.D. University of Massachusetts Directed by: Dr. John G. Stoffolano, Jr. Vision of Tabanus nigrovittatus was studied using electrophysiological and behavioral methods. Spectral sensitivity, determined by extracellular electroretinograms, was greatest at 477 nm (blue) and 520 nm (green) with a smaller peak at <342 nm (UV). Two \ long wavelength photoreceptors at 477 nm and 520 nm are believed to be present with a possible third photoreceptor in the UV. Spectral sensitivity curves of male and female flies differed in proportions of blue and green photoreceptors, with males having a higher percentage of blue photoreceptors. The sensitivity of males decreased slightly from 1 day of age to 8-18 days of age. Parous females (8- to 18-day-old) were considerably more sensitive than nulliparous (one day old) females. The importance of color and contrast in attraction of flies was determined by conducting choice tests with panels under field conditions. Almost all flies collected were host-seeking parous females. From a series of tests with black and white patterned vii panels, it was determined that maximum attraction was to a large, solid object with simple edges, contrasting highly against the background regardless of whether the object was black or white. Attraction to intensity contrast occurred independent of hue. Host-seeking flies were most attracted by blue, followed by black and red (low reflectance 400 - 800 nm). Yellow, yellow-green, white and ultraviolet were not attractive. Increasing or decreasing intensity of hues increased attraction of flies, a result of increased contrast against the background. The effect of background intensity on attraction to panels was determined and high intensity contrast against the background increased attraction of host-seeking flies. Panels of an attractive l hue, however, were most attractive when a low intensty hue was used despite the contrast against the background. viii TABLE OF CONTENTS DEDICATION . iv ACKNOWLEDGEMENTS . v ABSTRACT . vii INTRODUCTION . 1 Chapter I. LITERATURE REVIEW . 4 Introduction . 4 Importance of shape . 5 Interaction of odor with visual cues . 8 Importance of color in attraction . 10 II. SPECTRAL SENSITIVITY OF TABANUS NIGROVITTATUS MACQUART .. 14 Introduction . 14 Materials and Methods .. 15 Results . 24 Discussion . 48 Conclusion .. 61 III. THE IMPORTANCE OF PATTERN IN VISUAL ATTRACTION OF TABANUS NIGROVITTATUS MACQUART . 63 Introduction . 63 Materials and Methods . 64 Results . 74 Discussion . 87 Conclusion . 94 IV. THE IMPORTANCE OF HUE AND INTENSITY ON VISUAL ATTRACTION OF FEMALE TABANUS NIGROVITTATUS MACQUART . 95 Introduction . 95 Materials and Methods . 96 Results . 107 Discussion . 112 Conclusion . 126 V. THE EFFECT OF BACKGROUND CONTRAST ON VISUAL ATTRACTION AND ORIENTATION OF TABANUS NIGROVITTATUS MACQUART . 128 Introduction ..... 128 ix Materials and Methods .. 129 Results .. 135 Discussion . 144 Conclusion . 149 LITERATURE CITED . 150 APPENDIX I . 166 LIST OF TABLES 1. Effect of shape of black objects against white backgrounds on capture of adult female Tabanus nigrovittatus on 30 x 30 cm panels .. 76 2. Effect of complexity of edge of black stars against white backgrounds on capture of adult female Tabanus nigrovittatus on 30 x 30 cm panels . 77 3. Effect of the size of a black circle on a white background on capture of adult female Tabanus nigrovittatus on 30 x 30 cm panels . 78 4. Effect of number of black circles on a white background on capture of adult female Tabanus nigrovittatus on 30 x 30 cm panels ..... 79 5. Effect of number of white circles on a black background on capture of adult female Tabanus nigrovittatus on 30 x 30 cm panels ... 80 6. Effect of white squares on a black background on capture of adult female Tabanus nigrovittatus on 30 x 30 cm panels . 82 7. Effect of number of black squares on white background on capture of adult female Tabanus nigrovittatus on 30 x 30 cm panels .... 83 8. Effect of orientation of black stripes (2.16 cm wide) on a white background on captures of adult female Tabanus nigrovittatus on 30 x 30 cm panels ... 85 9. Effect of number of black vertical stripes on a white background on capture of adult female Tabanus nigrovittatus on 30 x 30 cm panels . 86 10. Response of Tabanus nigrovittatus to panels (30 x 30 cm) of various colors ..... 109 11. Effect of ultraviolet reflection on captures of adult female Tabanus nigrovittatus on 30 x 30 cm panels ... 110 12. Comparison of ultraviolet reflectance of background on captures of adult female Tabanus nigrovittatus on panels (30 x 30 cm) painted with a black circle . Ill xi ■ 13. Effect of intensity of cadmium yellow pale on captures of adult female Tabanus nigrovittatus on 30 x 30 cm panels . 113 14. Effect of intensity of yellow-green on captures of adult female Tabanus nigrovittatus on 30 x 30 cm panels .... 114 15. Effect of intensity of blue on captures of adult female Tabanus nigrovittatus on 30 x 30 cm panels ... 115 16. Effect of intensity of grey on captures of adult female Tabanus nigrovittatus on 30 x 30 cm panels ... 116 17. Comparison of intensity of grey background panels (60.8 x 60.8 cm) on collection of adult female Tabanus nigrovittatus on a series of test panels (30 x 30 cm) which ranged from 10 - 100% black .... 137 18. Comparison of intensity of grey background panels (60.8 x 60.8 cm) on collection of adult female Tabanus nigrovittatus on a series of test panels (30 x 30 cm) which ranged from 10 - 100% blue . 138 19. Behavior of female T^. nigrovittatus as observed upon approach to test panel and background panel on 4 August, 1982 ... 142 20. Height of initial approach of female TT. nigrovittatus to test panel and background panel .. 143 21. Diagrammatic representation of collection of female T_. nigrovittatus on test panels and background panels using a grid of 64 squares (7.6 x 7.6 cm) .