NEGOTIATION OF BARRIERS BY INTACT AND BRAIN-LESIONED COCKROACHES By Cynthia Marie Harley Submitted in partial fulfillment of the requirements For the degree of Doctor of Philosophy Adviser: Dr. Roy Ritzmann Department of Biology CASE WESTERN RESERVE UNIVERSITY January 2010 CASE WESTERN RESERVE UNIVERSITY SCHOOL OF GRADUATE STUDIES We hereby approve the thesis/dissertation of _____________________________________________________ candidate for the ______________________degree *. (signed)_______________________________________________ (chair of the committee) ________________________________________________ ________________________________________________ ________________________________________________ ________________________________________________ ________________________________________________ (date) _______________________ *We also certify that written approval has been obtained for any proprietary material contained therein. Copyright © by Cynthia Marie Harley All rights reserved To my husband Chris TABLE OF CONTENTS Thesis Summary ................................................................................................................ 1 Chapter 1: Introduction ...................................................................................................................... 3 TRANSITIONAL BEHAVIORS .............................................................................................. 5 ETHOGRAMS ..................................................................................................................... 8 HEAD SENSORS ................................................................................................................. 9 Head sensor anatomy ................................................................................................. 10 Antennae ..................................................................................................................... 10 Maxillary Palps .......................................................................................................... 12 Vision ......................................................................................................................... 13 Ocelli .................................................................................................................. 13 Compound Eyes ................................................................................................. 14 PROCESSING SENSORY INFORMATION ............................................................................ 15 THE INSECT BRAIN ......................................................................................................... 16 Mushroom Bodies ...................................................................................................... 18 Antenno Cerebral Tract .............................................................................................. 20 Central Complex ........................................................................................................ 21 Genetic Lesions .................................................................................................. 24 Mechanical Lesions ........................................................................................... 25 i Recordings in the central complex ..................................................................... 25 Protocerebral Bridge .......................................................................................... 28 Central body: the fanshaped body and ellipsoid body ....................................... 29 Lateral Accessory Lobe ..................................................................................... 30 MY GOAL ....................................................................................................................... 30 MOTIVATION .................................................................................................................. 31 FIGURES.......................................................................................................................... 33 Figure 1-1 Insect Nervous System ..................................................................... 34 Figure 1-2 Head Sensors .................................................................................... 35 Figure 1-3 Representation of the main regions within the protocerebrum of the cockroach brain .................................................................................................. 36 Figure 1-4 Schematic of the Central Complex .................................................. 37 Chapter 2: Characterization of obstacle negotiation behaviors in the cockroach, Blaberus discoidalis ......................................................................................................................... 44 SUMMARY ...................................................................................................................... 45 INTRODUCTION ............................................................................................................... 46 MATERIALS AND METHODS ............................................................................................ 49 Animals ...................................................................................................................... 49 Experimental Arena and Obstacles ............................................................................ 50 Lighting Conditions.................................................................................................... 51 Measurements ............................................................................................................. 52 ii Antennal Ablations ..................................................................................................... 53 Ethograms ................................................................................................................... 54 Climbing Strategies .................................................................................................... 57 Shelf Height ................................................................................................................ 58 Eye Coverings ............................................................................................................ 59 RESULTS ......................................................................................................................... 60 Block Obstacles .......................................................................................................... 60 Effect of Altered Antennal Length ............................................................................. 62 Shelf Obstacles ........................................................................................................... 64 Effects of Ambient Lighting ...................................................................................... 66 Role of Vision in Dark Light Response ..................................................................... 68 Effects of Changing Shelf Height .............................................................................. 68 Body Posture Under Different Lighting Conditions .................................................. 69 Antennal Position Under Differing Light Conditions ................................................ 70 DISCUSSION .................................................................................................................... 70 Distance From Block Affects Climbing Success Rate ............................................... 72 Detecting Alternate Routes ........................................................................................ 73 Ambient Lighting Influences Whether a Cockroach Climbs or Tunnels ................... 74 The Bias in Tunneling Was Only Present for Moderate Shelf Heights ..................... 74 Ocelli Detect Light Levels and Influence the Light Bias on Shelf Behavior ............. 75 FIGURES.......................................................................................................................... 77 Figure 2-1: Block Climbing Behavior ........................................................................ 77 Figure 2-2: Distance from the Obstacle and Climbing Success ................................. 78 iii Supplimental Figure 2-1: Normalized Distance from obstacle and climbing success .................................................................................................................................... 79 Figure 2-3: Strategies Used for Block Climbing ........................................................ 80 Figure 2-4: Ethograms of Block Climbing ................................................................. 81 Figure 2-5: Shelf Climbing and Tunneling is related to antennal contact ................. 82 Figure 2-6: The influence of shelf height and ambient lighting on climbing behavior .................................................................................................................................... 84 Figure 2-7: Ocelli Determine if it is light or dark ...................................................... 85 Figure 2-8: Antennae Sample the same space regardless of lighting ......................... 86 Suppliment 2-2 Antennae sample the same space regardless of lighting .................. 87 Table 2-1: Dwell time after specific antennal contact patterns .................................. 88 Chapter 3: Discrete Lesions in the cockroach brain and their effect on the negotiation of barriers