DOCSLIB.ORG

Optomotor Response Reduced by Procaine Injection in The

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Optomotor Response Reduced by Procaine Injection in The OPTOMOTOR RESPONSE REDUCED BY PROCAINE INJECTION IN THE CENTRAL COMPLEX OF THE COCKROACH, BLABERUS DISCOIDALIS BY: MALAVIKA KESAVAN Submitted in partial fulfillment of the requirements For the degree of Master of Science Dissertation Adviser: Dr. Roy Ritzmann Department of Biology CASE WESTERN RESERVE UNIVERSITY January, 2014 1 CASE WESTERN RESERVE UNIVERSITY SCHOOL OF GRADUATE STUDIES We hereby approve the thesis/dissertation of Malavika Kesavan candidate for the Master of Science degree *. (Committee Chair) Dr. Jean Burns Dr. Roy Ritzmann Dr. Mark Willis Dr. Barbara Freeman (date) 08/28/2013 2 TABLE OF CONTENTS Abstract ……………………………………………………………………………….. 8 INTRODUCTION ...………………………………………………………………….. 9 Basic anatomy of the B. discoidalis …………………………………………………. 11 External Anatomy …………………………………………………………….. 11 Internal Anatomy ……………………………………………………………... 11 The Head Ganglia in Insects ………………………………………………….. 12 The Central Complex: Anatomy ……………………………………………… 14 Focus of project ……………………………………………………………………… 16 Basic Visual Information Flow in Insects ………………………………………….. 16 Anatomy ……………………………………………………………………… 17 Basic Visual Movement Detection ………………………………………….... 18 The Central Complex ……………………………………………………………….. 19 Comparative Approach lends Insight into function of Central Complex .......... 19 Overview of Central Complex Development ………………………………… 19 The Central Complex's influence on Spatial Orientation …………………….. 21 The Central Complex Role in Changing Motor Behavior……………………… 22 The Central Complex and Memory …………………………………………... 25 Motor Behavior ……………………………………………………………………… 26 Locomotion …………………………………………………………………… 26 Escape Behavior ……………………………………………………………………... 28 Procaine ……………………………………………………………………………… 30 Significance of Project ………………………………………………………………. 31 3 METHODS …………………………………………………………………………... 31 Housing ……………………………………………………………………….. 31 Phase 1: Pre-trial …………………………………………………………….. 32 Phase 2: Injections ……………………………………………………………. 32 Phase 3: Trial ………………………………………………………….……… 33 Phase 4: Histology .…………………………………………………………... 34 Electrophysiology …………………………………………………………….. 36 Escape Behavior ……………………………………………………………… 37 Data Processing ………………………………………………………………. 37 Escape Response Analysis ………………………………………….. ………. 40 Post Injection Behavior ………………………………………………………. 41 Errors in Data Analysis ……………………………………………………….. 41 RESULTS …………………………………………………………………………… 43 Controls ……………………………………………………………………….. 43 The Procaine Effect on Optomotor Response ………………………………... 45 Activity Levels ................................................................................................... 50 Escape Response ……………………………………………………………… 51 Extracellular Brain Recording ……………………………………………….. 53 DISCUSSION ……………………………………………………………………….. 54 Central Complex Influence on Optomotor Response ………………………... 55 Effect of Procaine on Central Complex ………………………………. 55 Effect of Procaine on Behavior ………………………………………. 56 Activity Levels ………………………………………………………………... 57 4 Escape Response ……………………………………………………………… 58 CONCLUSION ……………………………………………………………………... 60 Future Work for Next Student ……………………………………………………... 61 Acknowledgments …………………………………………………………………… 62 References ……………………………………………………………………………. 63 5 LIST OF FIGURES AND TABLES Figure 1: Cockroach Central Nervous System ………..……………………………….. 12 Figure 2: Representation of the central complex images in 3D ………..….………….. 14 Table 1: Summary Table of central complex lesions ………………………………….. 25 Figure 3: Schematic of experimental set up (side-view) . ..…………………………… 31 Table 2: Histological Process …………………………………………………………. 35 Figure 4: Confocal Images of B. discoidalis brain with dye ………………………….. 36 Figure 5: Example of raw output ……………………………………………………… 38 Figure 6: Data processing method ……………………………………………………... 38 Figure 7: Example Angular Outputs ………………………………………………….. 40 Table 3: Summary of Experimental Groups ………………………………………….. 40 Figure 8: Examples of False Negatives ………………………………………………. 42 Figure 9: Examples of False Positives ………………………………………………... 43 Figure 10: Optomotor Responses for untreated cockroaches …………………..…… 44 Figure 11: Optomotor Responses for cockroaches with sham surgery ……….…….... 45 Table 4: Turn Response comparison between saline and 20% Procaine ……………... 46 Figure 12: Optomotor Responses for cockroaches injected with saline …………….... 47 Figure 13: Optomotor Responses for cockroaches injected with procaine …………… 48 Figure 14: Optomotor for cockroaches injected with 10% procaine …………………. 49 Table 5: Turn response comparison between saline and 10% procaine trials ………... 49 Figure 15: Comparison of optomotor response in all experimental groups …………... 50 Table 6: Average time spent Active during trial ……………………………………… 51 Figure 16: Average speed of escape for cockroaches under the influence of 20%....….. 52 6 Figure 17: 20% Procaine influence on central complex spiking activity …………….. 54 Figure 18: 10% Procaine influence on central complex spiking activity …………….. 54 7 Optomotor Response Reduced by Procaine Injection in the Central Complex of the Cockroach, Blaberus Discoidalis By: MALAVIKA KESAVAN Abstract The central complex is a group of midline neuropils found in all arthropods. In insects, circuits within the central complex play a role in processing visual and tactile information. Activity recorded in the central complex is correlated with and often precedes changes in step frequency and turning movement. Electrolytic lesions in the central complex adversely affect various locomotory behaviors. However, questions exist about collateral damage to areas outside of the central complex as the lesion probe was inserted. To address this issue, we developed a reversible chemical block of neural activity in the central complex using the anesthetic procaine. Black and white moving stripes induced an optomotor turning response in the cockroach, Blaberus discoidalis. After documenting the response in a normal individual, we injected a solution of 10% or 20% procaine into the central complex. Subjects with anesthetized central complex had a significant decrease in optomotor response up to 30 minutes after injections. Controls injected with saline showed no deficit. As the effects of the anesthetics diminished, the cockroach regained the ability to turn. While the optomotor response processing happens mostly within the cockroach brain, most escape circuitry is located in the thoracic ganglia. Nevertheless, the brain has been shown to influence escape response. We, therefore, extended our analysis to examine the effects of the procaine injection into the central complex on escape. Subjects with reduced output from the central complex 8 showed little deficit in escape speed. Electrophysiological recording showed that procaine reduced firing activity in the central complex. Introduction Cockroaches such as Blaberus discoidalis, a member of the arthropod phylum, are notoriously good at moving quickly in unpredictable and novel terrain. Despite their reputation as “simple” creatures most robotic work has been unable to span behavioral adaptability of these animals. How is the cockroach able to incorporate the vast complexity of its environment into its choices? The central complex has emerged as a leading contender as a higher order motor planning area in insects (Strauss & Heisenberg, 1993). The central complex receives multimodal sensory information ultimately outputting to the lateral accessory lobes where it can affect the neurons descending to the thoracic ganglia (Martin et al., 1999). The aim of my thesis project was to adapt a reversible block for examining the role of the central complex in controlling specific aspects of locomotor behavior. This technique was used to complement work done with electrolytic lesion in the central complex by a previous student in the laboratory. Electrolytic lesions in the central complex adversely affect various locomotory behaviors including turning; however, questions existed about collateral damage to areas outside of the central complex when the lesion probe was inserted(Harley & Ritzmann, 2010;Ritzmann et al., 2012). Though several controls were done to ensure that the surgery was not the cause of the behavior deficit, having a reversible neural effect would confirm these results. To address this issue, a reversible block of neural activity in the central complex was developed for this preparation using the local anesthetic, procaine. We believe refined versions of this 9 technique can be used to subtly manipulate central complex circuits allowing us to map information flow and ultimately further the understanding of the function of the central complex. In my experiments, an optomotor turning response was induced by displaying vertical black and white stripes that were moving horizontally in the visual field of B. discoidalis cockroaches while they were tethered on an air suspended ball. After documenting this response in normal individuals, a solution of 20% procaine was injected into the central complex. Subjects treated with procaine retained the ability to walk, though they rarely responded to moving stripes stimulus. On average, cockroaches with the anesthetized central complex showed a significant decrease in response to the visual stimuli up to 30 minutes after the injection. Cockroaches injected with saline showed no such deficit. Furthermore, cockroaches with no surgery performed on them acted in a similar manner to those injected with saline. As the effects of the anesthetic in the central complex diminished the animal regained the ability to respond to the visual stimuli
Load more

Recommended publications
  • Nest Defense and Conspecific Enemy Recognition in the Desert
    P1: JRX Journal of Insect Behavior [joib] pp1033-joir-474318 November 6, 2003 13:37 Style file version Feb 08, 2000 Journal of Insect Behavior, Vol. 16, No. 5, September 2003 (C 2003) Nest Defense and Conspecific Enemy Recognition in the Desert Ant Cataglyphis fortis Markus Knaden1 and Rudiger¨ Wehner1,2 Accepted July 16, 2003; revised August 12, 2003 This study focuses on different factors affecting the level of aggression in the desert ant Cataglyphis fortis. We found that the readiness to fight against conspecific ants was high in ants captured close to the nest entrance (0- and 1-m distances). At a 5-m distance from the nest entrance the level of aggression was significantly lower. As the mean foraging range in desert ants by far exceeds this distance, the present account clearly shows that in C. fortis aggressive behavior is displayed in the context of nest, rather than food-territory defense. In addition, ants were more aggressive against members of a colony with which they had recently exchanged aggressive encounters than against members of a yet unknown colony. This finding is discussed in terms of a learned, enemy- specific label-template recognition process. KEY WORDS: aggression; Cataglyphis; “dear-enemy” phenomenon; enemy recognition; territoriality. INTRODUCTION The desert ant Cataglyphis fortis (Wehner, 1983) is the only species of ants inhabiting the vast plains of the North African salt pans. The colonies of this medium-sized monomorphic Cataglyphis species (body length, 5.5– 9.6 mm; head width, 1.1–2.4 mm; [Wehner, 1983; Dillier, 1998]) comprise only about 50 foragers, which search individually for dead arthropods (Wehner, 1983, 1987).
    [Show full text]
  • Path Integration Controls Nest-Plume Following in Desert Ants
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Current Biology 22, 645–649, April 10, 2012 ª2012 Elsevier Ltd All rights reserved DOI 10.1016/j.cub.2012.02.029 Report Path Integration Controls Nest-Plume Following in Desert Ants Cornelia Buehlmann,1 Bill S. Hansson,1,2,* to leave and enter their nests via a central opening (Figure 2A; and Markus Knaden1,2,* for details, see Experimental Procedures). To exclude any 1Max Planck Institute for Chemical Ecology, Hans-Knoell nest-defining cues other than nest odor, we installed circular Strasse 8, 07745 Jena, Germany barriers (height, 0.1 m; Ø: 3.4 m) surrounding the arenas. A U-shaped aluminum channel (length, 2 m) pointing away from the arena was dug into the ground and led the ants under Summary the barrier toward the feeder. After about 30 min, the ants learned to enter the channel and pinpoint the feeder. Homing The desert ant Cataglyphis fortis is equipped with sophisti- ants had to pass along the channel, climb onto the arena via cated navigational skills for returning to its nest after a sand ramp, and locate the nest entrance in the center of foraging [1, 2]. The ant’s primary means for long-distance the arena. The visually identical arena setups allowed us to navigation is path integration, which provides a continuous transfer ants from the feeder of their own setup to a setup readout of the ant’s approximate distance [3] and direction connected either with a foreign nest or with no nest (no-nest [4] from the nest [5].
    [Show full text]
  • Vector Navigation in Desert Ants, Cataglyphis Fortis: Celestial Compass Cues Are Essential for the Proper Use of Distance Information
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by RERO DOC Digital Library Naturwissenschaften (2005) 92: 468–471 DOI 10.1007/s00114-005-0020-y SHORT COMMUNICATION Stefan Sommer · Rudiger¨ Wehner Vector navigation in desert ants, Cataglyphis fortis: celestial compass cues are essential for the proper use of distance information Received: 12 May 2005 / Accepted: 3 July 2005 / Published online: 15 September 2005 C Springer-Verlag 2005 Abstract Foraging desert ants navigate primarily by path absence of any optic flow-field cues (Ronacher and Wehner integration. They continually update homing direction and 1995; Ronacher et al. 2000). Instead, they seem to acquire distance by employing a celestial compass and an odome- the distance information primarily by proprioceptive ter. Here we address the question of whether information means (Wohlgemuth et al. 2001, 2002; Thielin-Bescond´ about travel distance is correctly used in the absence of and Beugnon 2005). However, how this information is directional information. By using linear channels that were acquired and finally used in path integration remains to be partly covered to exclude celestial compass cues, we were elucidated. In the present account we address the question able to test the distance component of the path-integration of whether desert ants, Cataglyphis fortis, are able to assess process while suppressing the directional information. Our the homing distance correctly if they are partly deprived results suggest that the path integrator cannot process the of directional information during their outbound run. distance information accumulated by the odometer while ants are deprived of celestial compass information.
    [Show full text]
  • Cataglyphis Desert Ants: a Good Model for Evolutionary Biology in Darwin's
    Cataglyphis desert ants: a good model for evolutionary biology in Darwin’s anniversary year—A review ALAIN LENOIR,1 SERGE ARON,2 XIM CERDÁ,3 AND ABRAHAM HEFETZ4 1IRBI, UMR CNRS 6035, Université François Rabelais, Faculté des Sciences, 37200 Tours, France. E-mail: [email protected] 2Université Libre de Bruxelles, Service Évolution Biologique & Écologie, C.P. 160/12 50, av. F.D. Roosevelt, 1050 Bruxelles, Belgique. E-mail: [email protected] 3Estación Biológica de Doñana, CSIC, Avda. Américo Vespucio s/n, E-41092 Sevilla, Spain. E-mail: [email protected] 4Department of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel. E-mail: [email protected] ABSTRACT Cataglyphis ants comprise one of the most characteristic groups of insects in arid regions around the Mediterranean basin and have been intensively stud- ied over the last 30 years. These ants are central-place foragers and scaven- gers, single-prey loaders that have become a model for insect navigation using sophisticated visual orientation, having lost pheromone orientation. They are highly heat-tolerant ants that forage close to their critical thermal limit dur- ing the hottest hours of the day, with their long-chain cuticular hydrocarbons protecting them from desiccation. This is exemplified in two Cataglyphis species, each of which developed different mechanisms for counteracting extreme heat when foraging: polymorphism of workers vs. physiological and behavioral adaptations. Several species in this genus have also become a model for studying nestmate recognition mechanisms. The role of cuticular hydrocarbons and the postpharyngeal gland as a reservoir of hydrocarbons in nestmate recognition was initially discovered mainly in Cataglyphis, includ- ing the first experimental demonstration of the Gestalt model of nestmate recognition.
    [Show full text]
  • Path Integration As the Basic Navigation Mechanism of the Desert Ant Cataglyphis Fortis (FOREL, 1902) (Hymenoptera: Formicidae)
    Myrmecological News 11 53-62 Vienna, August 2008 Path integration as the basic navigation mechanism of the desert ant Cataglyphis fortis (FOREL, 1902) (Hymenoptera: Formicidae) Bernhard RONACHER Abstract This review describes recent progress in the analysis of the fascinating navigation abilities of desert ants. On their for- aging excursions, ants of the genus Cataglyphis cover distances up to hundred thousand body lengths. Having found a prey item they return to their inconspicuous nests with high precision, using path integration as their major navigation aid. This account focuses on the question of how these ants measure their travelling distances, information that is an es- sential constituent of path integration. Recently it has been shown that Cataglyphis uses a stride integrator to measure walking distances. Remarkably, the ants' path integration module works precisely even when the animals forage in un- dulating terrain, e.g., when climbing over walls or hills. This indicates that the ants are able to measure the inclination of ascents or descents, and do integrate this information into their distance estimates. Navigation by means of path integra- tion is error prone due to its susceptibility to accumulate errors. Cataglyphis and other desert ant species use landmarks – if present – as additional navigational aid. Many studies were devoted to the interactions between the path integration system and landmarks. There are no indications that by combining vector and landmark information ants would acquire a representation of their environs in the sense of a "cognitive map". A lesson that we may learn from the small-brain navigator Cataglyphis is how complex, "high-level" behaviour is achieved by the interaction of rather simple, "low- level" subroutines.
    [Show full text]
  • A Review of Effects of Environment on Brain Size in Insects
    insects Review A Review of Effects of Environment on Brain Size in Insects Thomas Carle Faculty of Biology, Kyushu University, Fukuoka 819-0395, Japan; [email protected] Simple Summary: What makes a big brain is fascinating since it is considered as a measure of intelligence. Above all, brain size is associated with body size. If species that have evolved with complex social behaviours possess relatively bigger brains than those deprived of such behaviours, this does not constitute the only factor affecting brain size. Other factors such as individual experience or surrounding environment also play roles in the size of the brain. In this review, I summarize the recent findings about the effects of environment on brain size in insects. I also discuss evidence about how the environment has an impact on sensory systems and influences brain size. Abstract: Brain size fascinates society as well as researchers since it is a measure often associated with intelligence and was used to define species with high “intellectual capabilities”. In general, brain size is correlated with body size. However, there are disparities in terms of relative brain size between species that may be explained by several factors such as the complexity of social behaviour, the ‘social brain hypothesis’, or learning and memory capabilities. These disparities are used to classify species according to an ‘encephalization quotient’. However, environment also has an important role on the development and evolution of brain size. In this review, I summarise the recent studies looking at the effects of environment on brain size in insects, and introduce the idea that the role of environment might be mediated through the relationship between olfaction and vision.
    [Show full text]
  • Landmark Guidance and Vector Navigation in Outbound Desert Ants
    3370 The Journal of Experimental Biology 211, 3370-3377 Published by The Company of Biologists 2008 doi:10.1242/jeb.022715 Landmark guidance and vector navigation in outbound desert ants Tobias Merkle1,* and Rüdiger Wehner2 1Centre for Visual Sciences, Research School of Biological Sciences, Australian National University, Canberra ACT 2601, Australia and 2Institute of Zoology and Brain Research Institute, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland *Author for correspondence (e-mail: [email protected]) Accepted 6 September 2008 SUMMARY This study deals with the influence landmark information has on the foraging behaviour of the desert ant, Cataglyphis fortis, especially with the interaction of such landmark information with the antsʼ path integration system. We show in the first experiment that desert ants that are captured immediately after leaving their nest and then transferred to a remote test area search for the nest rather than activate their previous path integration vector. In a second experiment, the ants had been trained to a landmark corridor on their way to the feeder. In the critical test situation, they were again captured immediately after they had left the nest and transferred to a test field where they faced one of the following three situations: (1) the same landmark corridor as used during the training phase, (2) no landmarks at all and (3) a landmark corridor rotated by 90 deg. as compared with the training situation. Nearly all ants in test situation (1) eventually followed the landmark corridor but most of them never reached the fictive feeder. In situation (2), the ants searched around the nest entrance.
    [Show full text]
  • Shearwaters Know the Direction and Distance Home but Fail to Encode Intervening Obstacles After Free-Ranging Foraging Trips
    Shearwaters know the direction and distance home but fail to encode intervening obstacles after free-ranging foraging trips Oliver Padgeta,1, Geoff Stanleyb,2, Jay K. Willisa, Annette L. Fayeta, Sarah Bonda, Louise Mauricec, Akiko Shojid, Ben Deana, Holly Kirka, Ignacio Juarez-Martineza, Robin Freemane, Mark Boltonf, and Tim Guilforda,1 aDepartment of Zoology, Oxford University, OX1 3SZ Oxford, United Kingdom; bDepartment of Physics, Oxford University, OX1 3PJ Oxford, United Kingdom; cBritish Geological Survey, OX10 8ED Wallingford, United Kingdom; dGraduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki 305-8572, Japan; eZoological Society of London, Institute of Zoology, NW1 4RY London, United Kingdom; and fCentre for Conservation Science, Royal Society for the Protection of Birds, SG19 2DL Sandy, United Kingdom Edited by Carol A. Barnes, University of Arizona, Tucson, AZ, and approved September 10, 2019 (received for review March 6, 2019) While displacement experiments have been powerful for deter- rearing (10, 11). We analyzed a large extant Manx shearwater mining the sensory basis of homing navigation in birds, they have Global Positioning System (GPS) tracking dataset (707 foraging left unresolved important cognitive aspects of navigation such as trips from 359 individuals) to determine what, at the end of their what birds know about their location relative to home and the trips, shearwaters knew about the direction and distance home. anticipated route. Here, we analyze the free-ranging Global To allow cognitive inferences to be made from their homing Positioning System (GPS) tracks of a large sample (n = 707) of behavior, we analyzed shearwater homing over a natural contrast Manx shearwater, Puffinus puffinus, foraging trips to investigate, with different optimal solutions depending on their cognitive from a cognitive perspective, what a wild, pelagic seabird knows representation of space.
    [Show full text]
  • Principles of Insect Path Integration
    Europe PMC Funders Group Author Manuscript Curr Biol. Author manuscript; available in PMC 2019 April 14. Published in final edited form as: Curr Biol. 2018 September 10; 28(17): R1043–R1058. doi:10.1016/j.cub.2018.04.058. Europe PMC Funders Author Manuscripts Principles of insect path integration Stanley Heinze*,1, Ajay Narendra2, and Allen Cheung3 1Lund University, Lund, Sweden 2Macquarie University, Sydney, Australia 3The University of Queensland, Queensland Brain Institute, Upland Road, St. Lucia, Queensland, Australia Abstract Continuously monitoring its position in space relative to a goal is one of the most essential tasks for an animal that moves through its environment. Species as diverse as rats, bees, and crabs achieve this by integrating all changes of direction with the distance covered during their foraging trips, a process called path integration. They generate an estimate of their current position relative to a starting point, enabling a straight-line return (home vector). While in theory path integration always leads the animal precisely back home, in the real world noise limits the usefulness of this strategy when operating in isolation. Noise results from stochastic processes in the nervous system and from unreliable sensory information, particularly when obtaining heading estimates. Path integration, during which angular self-motion provides the sole input for encoding heading (idiothetic path integration), results in accumulating errors that render this strategy useless over Europe PMC Funders Author Manuscripts long distances. In contrast, when using an external compass this limitation is avoided (allothetic path integration). Many navigating insects indeed rely on external compass cues for estimating body orientation, whereas they obtain distance information by integration of steps or optic-flow- based speed signals.
    [Show full text]
  • Lasius Flavus and L
    A University of Sussex DPhil thesis Available online via Sussex Research Online: http://sro.sussex.ac.uk/ This thesis is protected by copyright which belongs to the author. This thesis cannot be reproduced or quoted extensively from without first obtaining permission in writing from the Author The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the Author When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given Please visit Sussex Research Online for more information and further details Chemical Based Communication and its Role in Decision Making Within the Social Insects Sam Jones A thesis submitted to the University of Sussex, Department of Life Sciences, for the degree of Doctor of Philosophy September 2013 Supervisors: Jonathan P. Bacon & Francis L.W. Ratnieks This thesis, whether in the same or different form, has not been previously submitted to this or any other University for a degree ii Abstract This thesis investigates chemical communication and decision making in a stingless bee (Tetragonisca angustula) and two species of ants (Lasius flavus and L. niger). Complex chemical signalling and seemingly elaborate behavioural patterns based upon decisions made by individuals of a colony have facilitated the evolution of social living in these insects. This thesis investigates two important features of social living that involve these features: nest mate recognition and navigation. The first part of this thesis (Chapter 3 and Appendix 3) investigates nestmate recognition and nest defence in the Neotropical stingless bee T.
    [Show full text]
  • The Role of Landscapes and Landmarks in Bee Navigation: a Review
    insects Review The Role of Landscapes and Landmarks in Bee Navigation: A Review Bahram Kheradmand * and James C. Nieh Section of Ecology, Behavior, and Evolution, Division of Biological Sciences, UC San Diego, La Jolla, CA 92093, USA; [email protected] * Correspondence: [email protected]; Tel.: +1-858-822-5010 Received: 31 August 2019; Accepted: 9 October 2019; Published: 12 October 2019 Abstract: The ability of animals to explore landmarks in their environment is essential to their fitness. Landmarks are widely recognized to play a key role in navigation by providing information in multiple sensory modalities. However, what is a landmark? We propose that animals use a hierarchy of information based upon its utility and salience when an animal is in a given motivational state. Focusing on honeybees, we suggest that foragers choose landmarks based upon their relative uniqueness, conspicuousness, stability, and context. We also propose that it is useful to distinguish between landmarks that provide sensory input that changes (“near”) or does not change (“far”) as the receiver uses these landmarks to navigate. However, we recognize that this distinction occurs on a continuum and is not a clear-cut dichotomy. We review the rich literature on landmarks, focusing on recent studies that have illuminated our understanding of the kinds of information that bees use, how they use it, potential mechanisms, and future research directions. Keywords: landmark detection; salience; visual information; multimodal navigation; Apis mellifera 1. Introduction 1.1. What Are Landmarks? A major and fascinating question in the study of animal cognition is how animals identify, remember, and use landmarks to navigate.
    [Show full text]
  • The Architecture of the Desert Ant's Navigational Toolkit (Hymenoptera: Formicidae)
    Myrmecological News 12 85-96 Vienna, September 2009 The architecture of the desert ant's navigational toolkit (Hymenoptera: Formicidae) Rüdiger WEHNER Abstract In the last decades North African desert ants of the genus Cataglyphis FOERSTER, 1850 – and more recently their eco- logical equivalents in the Namib desert (Ocymyrmex EMERY, 1886) and Australia (Melophorus LUBBOCK, 1883) – have become model organisms for the study of insect navigation. While foraging individually over distances of many thou- sand times their body lengths in featureless as well as cluttered terrain, they navigate predominantly by visual means using vector navigation (path integration) and landmark-guidance mechanisms as well as systematic-search and target- expansion strategies as their main navigational tools. In vector navigation they employ several ways of acquiring infor- mation about directions steered (compass information) and distances covered (odometer information). In landmark guid- ance they rely on view-based information about visual scenes obtained at certain vantage points and combined with certain steering (motor) commands of what to do next. By exploring how these various navigational routines interact, the current position paper provides a hypothesis of what the architecture of the ant's navigational toolkit might look like. The hypothesis is built on the assumption that the toolkit consists of a number of domain-specific routines. Even though these routines are quite rigidly preordained (and get modified during the ant's lifetime by strictly task-dependent, rapid learning processes), they interact quite flexibly in various, largely context-dependent ways. However, they are not suited to provide the ant with cartographic information about the locations of places within the animal's foraging environment.
    [Show full text]