DOCSLIB.ORG

Body Size and Evolution of Motion Dazzle Coloration in Lizards

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Body Size and Evolution of Motion Dazzle Coloration in Lizards Behavioral The official journal of the ISBE Ecology International Society for Behavioral Ecology Behavioral Ecology (2017), 00(00), 1–8. doi:10.1093/beheco/arx128 Original Article Body size and evolution of motion dazzle coloration in lizards Gopal Murali and Ullasa Kodandaramaiah IISER-TVM Centre for Research and Education in Ecology and Evolution (ICREEE), School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala PO, Vithura, Thiruvananthapuram 695 551, India Received 4 April 2017; revised 2 July 2017; editorial decision 22 August 2017; accepted 13 September 2017. “Motion dazzle” patterns are a form of defensive coloration suggested to prevent successful capture during motion by causing preda- tors to misjudge the direction or speed of prey movement. Several studies have found results supporting this idea but little is known about the factors that favor the evolution of these antipredator colorations. A recent experimental study has suggested that the lon- gitudinal striped patterns on the body of lizards can redirect attacks to the tail via the motion dazzle effect. Using a virtual predation experiment with humans and a phylogenetic comparative analysis, we show that evolution of longitudinal striped coloration is associ- ated with prey size. Experiments showed that longitudinal stripes located at the anterior reduced lethal attacks (i.e., attacks directed to the anterior and centre) but this benefit was greater for shorter prey. Our comparative analysis revealed a negative association between stripe occurrence and body length but no association between stripes and body width. Overall, our results suggest that the dazzle effect produced by stripes is more advantageous in shorter lizards than in longer ones and that the error induced by stripes might be distributed along the axis parallel to the prey trajectory. We discuss reasons why dazzle coloration could be associated with evolution of smaller body size in animals. Key words: antipredator adaption, lizards, motion dazzle, prey size, redirection, stripes. INTRODUCTION “motion dazzle” patterns, can inhibit capture by disrupting Animals exhibit a tremendous diversity of color patterns, and predators’ perception of trajectory or speed of a moving prey research over a century has identified numerous ways in which (Thayer 1909). This form of protective color patterns are thus animals use these patterns to reduce predation (Thayer 1909; Cott expected to be found in actively moving animals where the ben- 1940; Ruxton et al. 2004). The most common strategies include efit of the lowered probability of successful capture outweighs camouflage through background matching (Stevens and Merilaita the cost of enhanced detectability (Stevens et al. 2011). Several 2009), masquerade (Skelhorn et al. 2010), disruptive coloration recent studies utilizing humans attacking virtual patterned prey (Cuthill et al. 2005), and countershading (Rowland et al. 2008), all on a computer screen have found support for the idea that of which decrease the probability of detection or recognition, and motion dazzle coloration can reduce predation when the prey is are most effective when the animal remains stationary (Stevens et al. moving (Stevens et al. 2008; von Helversen et al. 2013; Hogan 2011; Hall et al. 2013). However, animals need to move for many et al. 2016). Experimental studies have examined aspects such reasons including foraging and searching for mates, and the proba- as varying speed (Hogan et al. 2017), internal contrast (Scott- bility of detection by predators is higher when the prey is in motion Samuel et al. 2011; Hogan et al. 2016), and orientation of the (Martel and Dill 1995; Hailman 1977; Cooper et al. 2008; Ioannou patterns (Hughes et al. 2015) on the effectiveness of dazzle mark- and Krause 2009). Yet, we are only now beginning to understand ings. Yet, we lack an understanding of why certain species rely how certain color patterns can protect prey during motion (Stevens on motion dazzle coloration, while others rely on camouflage as et al. 2008; Stevens et al. 2011; Pike 2015; Umeton et al. 2017). primary defensive strategy. We also know little about the mor- Thayer (1909) hypothesized that certain high contrast repeti- phological or life-history traits of prey animals that could influ- tive color patterns (stripes, bands, and zigzags) now termed ence the evolution of dazzle markings and their effectiveness. One such trait which can affect the evolution of dazzle patterns could be prey body size. Since large animals are inherently more conspicuous, signals which require conspicuousness are expected to Address correspondence to G. Murali. E-mail: [email protected]. be favored in larger animals (Hagman and Forsman 2003; Hossie © The Author 2017. Published by Oxford University Press on behalf of the International Society for Behavioral Ecology. All rights reserved. For permissions, please e-mail: [email protected] Downloaded from https://academic.oup.com/beheco/article-abstract/doi/10.1093/beheco/arx128/4554414/Body-size-and-evolution-of-motion-dazzle by Central Library, IISER Thiruvananthapuram user on 17 October 2017 Page 2 of 8 Behavioral Ecology et al. 2015) and conversely, evolution of cryptic coloration might in comparative studies on mammals (e.g., Brown and Maurer 1989; be favored in smaller animals (Karpestam et al. 2014). On the Fritz et al. 2009), tetrapods have been excluded in studies on fishes other hand, a larger prey is also more easily caught during motion (Olden et al. 2007) and marine species have been omitted from compared to smaller ones (Van Damme and Van Dooren 1999; studies on birds (Orme et al. 2006). Although snakes are likely Clemente and Wilson 2015). Therefore, dazzle patterns may not nested within lizards (Zheng and Wiens 2016, but see Zhou et al. be effective for larger prey. Thus, the benefit of conspicuous pro- 2006 who show that snakes are sister to lizards), comparative stud- tective patterns such as dazzle markings which operate in motion ies on lizards (e.g., Meiri 2010; Halperin et al. 2016; Gainsbury and may depend on the body size of the animal, although this has not Meiri 2017) have not included snakes because of their distinctness been tested. from lizards. We have similarly excluded snakes in our analysis, as Recently, Murali and Kodandaramaiah (2016) expanded the they are not relevant to our hypotheses, which are explicitly based motion dazzle hypothesis by proposing the redirection hypothesis, on the redirection of attacks by anterior stripes towards plainly where dazzle coloration on the anterior part of a moving prey colored tails. Following a previous study (Halperin et al. 2016), animal can redirect attempted strikes to less vulnerable poste- we also eliminated the below families from the analysis based on rior parts (Murali and Kodandaramaiah 2016). Since high con- specific reasons. Most species in the family Gekkonidae are noctur- trast longitudinal striped color patterns are commonly found nal, which are not directly relevant to the hypotheses under con- on the body (i.e., trunk) of lizards, they proposed that stripes sideration. We also excluded chameleons (Chamaeleonidae), which on lizards might function by redirecting attacks to the expend- are known to change color rapidly based on the signaling context able tail. A recent comparative analysis also supports the idea (Ligon and McGraw 2013). that stripes in lizards may work in motion against predation Color pattern judgment is dependent on many factors, includ- (Halperin et al. 2016). ing the receiver’s visual system and environmental factors (Endler Interestingly, longitudinal stripes in many lizard species are pres- 1991, 1992). Despite this, pattern classification by human observers ent only in juveniles (e.g., Acanthodactylus beershebensis and Plestiodon is commonly employed in comparative studies involving body pat- laticeps; Taylor 1935; Hawlena et al. 2006) and this ontogenic loss terns of animals (Kodandaramaiah 2009; Allen et al. 2013; Kelley of stripes appears to be restricted to species with longer body length et al. 2013; Arbuckle and Speed 2015). Although it would be ideal (Taylor 1935). Moreover, in many lizard species that are polymor- to develop a computer vision based tool to categorize color patterns phic with respect to presence or absence of stripes, striped individu- (e.g., see Stoddard et al. 2014), this requires photographic images als tend to be smaller (Podarcis hispanicus, Ortega et al. 2015; Scelarcis taken in controlled conditions, which is not feasible for the current perspicillata, Carretero et al. 2006). In the skink Plestiodon latiscutatus, study given the large scale. We acknowledge that pattern classifi- individuals of populations with reduced predation pressure become cation by humans can have subjective bias but we employed mul- larger as well as lose stripes (Brandley et al. 2014). The above stud- tiple strategies to ensure that our pattern categorization was robust. ies thus suggest that the functioning of longitudinal stripes in liz- First, pattern classification was performed by 3 volunteers all of ards might be dependent on body size. whom were naïve to the hypotheses and were recruited opportu- We use 2 approaches to address the role of body size in the func- nistically. Volunteers were first year undergraduate students from tioning of longitudinal stripes in attack redirection via the motion the same institute. Each volunteer was given written instructions for dazzle effect.
Load more

Recommended publications
  • Reproductive PATTERNS and Human-INFLUENCED Z]`Ynagj Af Zjgof Z]Yjk& Aehda[Ylagfk ^Gj the Conservation of LARGE Carnivores
    P Natural and Department Ecology of Resource Management Fgjo]_aYfMfan]jkalqg^Da^]K[a]f[]kMfan]jkal]l]l^gjeadb¬ hilosophiae Doctor <]hYjlYe]flg\]:ag\an]jka\Y\q?]klaf9eZa]flYd& Universidad de León E-24071 León, Spain. www.unileon.es Reproductive patterns and human-influenced ( P Z]`YnagjafZjgofZ]Yjk&Aehda[Ylagfk^gj h D) the conservation of large carnivores. Thesis 2010:01 Thesis J]hjg\mckbgfke¬fkl]jg_e]ff]kc]kcYhlYl^]j\k]f\jaf_`gkZjmfZb¬jf& Cgfk]cn]fk]j^gjZ]nYjaf_]fYnklgj]jgn\qj& Andrés Ordiz %g_Zagnal]fkcYh Reproductive patterns and human-influenced behavior in brown bears Implications for the conservation of large carnivores Reproduksjonsmønster og menneskeskapt atferdsendring hos brunbjørn Konsekvenser for bevaringen av store rovdyr Philosophiae Doctor (PhD) Thesis Andrés Ordiz Dept. of Ecology and Natural Resource Management Norwegian University of Life Sciences & Dept. de Biodiversidad y Gestión Ambiental Universidad de León Ås/León 2010 UMB Thesis number 2010: 01 ISSN 1503-1667 ISBN 978-82-575-0913-2 This thesis has been conducted as a PhD research co-supervision agreement between the Norwegian University of Life Sciences and the University of León (Spain). I acknowledge the effort of J. E. Swenson, E. de Luis Calabuig and E. Panero to succeed in establishing the agreement. PhD supervisors Prof. Jon E. Swenson (main supervisor) Department of Ecology and Natural Resource Management Norwegian University of Life Sciences Pb. 5003, 1432 Ås, Norway Dr. Ole-Gunnar Støen Department of Ecology and Natural Resource Management Norwegian University of Life Sciences Pb. 5003, 1432 Ås, Norway Prof. Miguel Delibes de Castro Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas Avenida Américo Vespucio s/n Isla de la Cartuja E-41092 Sevilla, Spain Adjudication committee Prof.
    [Show full text]
  • Pan 1 Recent Advances in Elucidating the Function of Zebra Stripes
    Pan 1 Recent Advances in Elucidating the Function of Zebra Stripes: Parasite Avoidance and Thermoregulation Do Not Resolve the Mystery Introduction Why are zebras striped? This question has baffled biologists for ages since the time of Darwin (Darwin 545). Although we remain far from an answer, past research was not done in vain. Currently, as much as 18 different theories have been proposed (Horváth et al. “EETSDNCZ” 1). These proposed explanations largely fall into four categories: 1) Predator avoidance through crypsis and various types of visual confusion (Ruxton 238), 2) reinforcement of social interactions (239), 3) ectoparasite deterrence (241), and 4) thermoregulation (239). Among the four groups of hypotheses, only the latter two have gained some support. The speculations that stripes help zebras blend in with tall grass (238), appear larger when in a group (237), or dazzle vertebrate predators like lions or spotted hyenas (238) were all but rejected because of the lack of empirical support and not because of the lack of trying (Caro et al. “TFOZS” 3; Larison et al. “HTZGIS” 3; Ruxton 238). Similarly, the idea that zebra stripes provide social benefits such as individual identification and bonding remains largely speculative (Ruxton 240), if not just outright rejected (Caro et al. “TFOZS” 3). Many of the hypotheses also do not actually suggest a fitness benefit but explain how the zebras interact (Ruxton 239). Therefore, they insufficiently explain why zebra stripes evolved in the first place. In contrast, overwhelming empirical evidence support the hypothesis that ‘zebra like’ stripes deter ectoparasites like glossinids and tabanids (Blaho et al.
    [Show full text]
  • Benefits of Zebra Stripes: Behaviour of Tabanid Flies Around Zebras and Horses
    Caro, T. , Argueta, Y., Briolat, E., Bruggink, J., Kasprowsky, M., Lake, J., Mitchell, M., Richardson, S., & How, M. (2019). Benefits of zebra stripes: behaviour of tabanid flies around zebras and horses. PLoS ONE, 14(2), [e0210831]. https://doi.org/10.1371/journal.pone.0210831 Publisher's PDF, also known as Version of record License (if available): CC BY Link to published version (if available): 10.1371/journal.pone.0210831 Link to publication record in Explore Bristol Research PDF-document This is the final published version of the article (version of record). It first appeared online via PLoS at DOI: 10.1371/journal.pone.0210831. Please refer to any applicable terms of use of the publisher. University of Bristol - Explore Bristol Research General rights This document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/red/research-policy/pure/user-guides/ebr-terms/ RESEARCH ARTICLE Benefits of zebra stripes: Behaviour of tabanid flies around zebras and horses 1 1 2 3 Tim CaroID *, Yvette Argueta , Emmanuelle Sophie Briolat , Joren Bruggink , 2 4 2 2 Maurice Kasprowsky , Jai Lake , Matthew J. Mitchell , Sarah RichardsonID , 4 Martin HowID 1 Department of Wildlife, Fish and Conservation Biology, University of California Davis, Davis, California, United States of America, 2 Centre for Ecology and Conservation Biosciences, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Penryn, Cornwall, United Kingdom, 3 Aeres University of Applied Sciences, Almere, Netherlands, 4 School of Biological Sciences, University of Bristol, Bristol, United Kingdom * [email protected] a1111111111 Abstract a1111111111 a1111111111 Averting attack by biting flies is increasingly regarded as the evolutionary driver of zebra a1111111111 stripes, although the precise mechanism by which stripes ameliorate attack by ectoparasites a1111111111 is unknown.
    [Show full text]
  • Antipredator Deception in Terrestrial Vertebrates
    Current Zoology 60 (1): 16–25, 2014 Antipredator deception in terrestrial vertebrates Tim CARO* Department of Wildlife, Fish and Conservation Biology, and Center of Population Biology, University of California, Davis, CA 95616, USA Abstract Deceptive antipredator defense mechanisms fall into three categories: depriving predators of knowledge of prey’s presence, providing cues that deceive predators about prey handling, and dishonest signaling. Deceptive defenses in terrestrial vertebrates include aspects of crypsis such as background matching and countershading, visual and acoustic Batesian mimicry, active defenses that make animals seem more difficult to handle such as increase in apparent size and threats, feigning injury and death, distractive behaviours, and aspects of flight. After reviewing these defenses, I attempt a preliminary evaluation of which aspects of antipredator deception are most widespread in amphibians, reptiles, mammals and birds [Current Zoology 60 (1): 16 25, 2014]. Keywords Amphibians, Birds, Defenses, Dishonesty, Mammals, Prey, Reptiles 1 Introduction homeotherms may increase the distance between prey and the pursuing predator or dupe the predator about the In this paper I review forms of deceptive antipredator flight path trajectory, or both (FitzGibbon, 1990). defenses in terrestrial vertebrates, a topic that has been Last, an antipredator defense may be a dishonest largely ignored for 25 years (Pough, 1988). I limit my signal. Bradbury and Vehrencamp (2011) state that “true scope to terrestrial organisms because lighting condi- deception occurs when a sender produces a signal tions in water are different from those in the air and whose reception will benefit it at the expense of the antipredator strategies often differ in the two environ- receiver regardless of the condition with which the sig- ments.
    [Show full text]
  • Arbeitsvorhaben 2015/2016
    ^o_bfqpsloe^_bk=abo=cbiiltp = = = cbiiltp Û =molgb`qp= OMNRLOMNS= Herausgeber: Wissenschaftskolleg zu Berlin Wallotstraße 19 14193 Berlin Tel.: +49 30 89 00 1-0 Fax: +49 30 89 00 1-300 [email protected] wiko-berlin.de Redaktion: Angelika Leuchter Redaktionsschluss: 17. Juli 2015 Dieses Werk ist lizenziert unter einer Creative Commons Namensnennung - Nicht-kommerziell - Keine Bearbeitung 3.0 Deutschland Lizenz INHALT VORWORT ________________________________ 4 L A I T H A L - SHAWAF _________________________ 6 D O R I T B A R - ON ____________________________ 8 TATIANA BORISOVA ________________________ 10 V I C T O R I A A . BRAITHWAITE __________________ 12 JANE BURBANK ____________________________ 14 ANNA MARIA BUSSE BERGER __________________ 16 T I M C A R O ________________________________ 18 M I R C E A C Ă RTĂ RESCU _______________________ 20 B A R B A R A A . CASPERS _______________________ 22 DANIEL CEFAÏ _____________________________ 24 INNES CAMERON CUTHIL L ___________________ 26 LORRAINE DASTON _________________________ 28 CLÉMENTINE DELISS ________________________ 30 HOLGER DIESSEL ___________________________ 32 ELHADJI IBRAHIMA DIO P ____________________ 34 PAULA DROEGE ____________________________ 36 DIETER EBERT _____________________________ 38 FINBARR BARRY FLOOD ______________________ 40 RAGHAVENDRA GADAGKAR __________________ 42 PETER GÄRDENFORS ________________________ 44 LUCA GIULIANI ____________________________ 46 SUSAN GOLDIN - MEADOW ____________________ 48 M I C H A E L D . GORDIN ________________________ 50
    [Show full text]
  • Merilaita, S., Scott-Samuel, N., & Cuthill, I. (2017). How Camouflage
    Merilaita, S. , Scott-Samuel, N., & Cuthill, I. (2017). How camouflage works. Philosophical Transactions B: Biological Sciences, 372, 20160341. [20160341]. https://doi.org/10.1098/rstb.2016.0341 Peer reviewed version Link to published version (if available): 10.1098/rstb.2016.0341 Link to publication record in Explore Bristol Research PDF-document This is the final published version of the article (version of record). It first appeared online via The Royal Society Philpspphical Transactions at http://rstb.royalsocietypublishing.org/content/372/1724/20160341#sec-14 . Please refer to any applicable terms of use of the publisher. University of Bristol - Explore Bristol Research General rights This document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/red/research-policy/pure/user-guides/ebr-terms/ Phil. Trans. R. Soc. B. article template Phil. Trans. R. Soc. B. doi:10.1098/not yet assigned How camouflage works Sami Merilaita1, Nicholas E. Scott-Samuel2, Innes C. Cuthill3 1 Department of Biosciences, Åbo Akademi University, Tykistökatu 6, FI-20520 Turku, Finland 2 Department of Experimental Psychology, University of Bristol, 12A Priory Road, Bristol BS8 1TN, UK 3 School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK Keywords: defensive coloration, signal-to-noise ratio, crypsis, visual search, animal coloration *Author for correspondence ([email protected]). †Present address: Department of Biosciences, Åbo Akademi University, Tykistökatu 6, FI-20520 Turku, Finland Summary For camouflage to succeed, an individual has to pass undetected, unrecognized or untargeted, and so it is the processing of visual information that needs to be deceived.
    [Show full text]
  • CEC Annual Report 2017
    Field Course Fortnight photo competition winner – “Students and biodiversity” – Bahamas, Yin Tan PENRYN CAMPUS PENRYN Centre for Ecology and Conservation Annual Report 2017 animal silhouettes border out of green? double page spread? montage? StillWelcome growing in size and reputation The CEC continues to be an exemplar in sharing One of the books, The Tale of the Turtle and the science with our community (see Science in Plastic Jellyfish has already been translated into the Community). Our school’s programme French and Greek, with other languages pending. continued apace reaching 4,000 students across As the year ends, it sees 20 schools. We were again represented at the This year was yet again one of great success for the Centre for me passing the baton of Cornwall Show and Penryn Day. In Falmouth Ecology and Conservation. In the Student Guild Awards we were leadership of the Centre for Week our flagship event, Science in the Square crowned Department of the Year for the Cornwall Campuses. Ecology and Conservation saw 3,000 visitors treated to a veritable This not only evidences the excellence of our staff but the and CLES Cornwall to cornucopia of accessible science and then to end strength of the relationship with our students, particularly our Professor Dave Hodgson the year, the fourth annual Science of Christmas student representatives, who engage so strongly in our agenda of (pictured right). It has been my honour to serve event was hosted by Falmouth Polytechnic. 2017 codevelopment and improvement of educational content and process. as Director and work for such an amazing group saw the fruition of the Professor Penny Stories of students and staff.
    [Show full text]
  • The Functional Significance of Colouration in Cetaceans
    Evol Ecol (2011) 25:1231–1245 DOI 10.1007/s10682-011-9479-5 ORIGINAL PAPER The functional significance of colouration in cetaceans Tim Caro • Karrie Beeman • Theodore Stankowich • Hal Whitehead Received: 2 December 2010 / Accepted: 23 March 2011 / Published online: 3 April 2011 Ó Springer Science+Business Media B.V. 2011 Abstract Cetaceans show many of the classic mammalian colouration patterns, such as uniform colouration, countershading, and prominent patches of colour, all within one relatively small taxon. We collated all the functional hypotheses for cetacean colouration that have been put forward in the literature and systematically tested them using com- parative phylogenetic analyses. We found that countershading is a mechanism by which smaller cetacean species may avoid being seen by their prey. We discovered that promi- nent markings are associated with group living, fast swimming, and ostentatious behaviour at the surface, suggesting that they function in intraspecific communication. White markings on several parts of the body seem to be involved in the capture of fish, squid, and krill. Therefore, several different selection pressures have shaped the great diversity of skin colouration seen in extant cetaceans, although background matching, disruptive colour- ation and interspecific communication do not appear to be involved. Keywords Colour Á Countershading Á Distinctive marks Á Whales Electronic supplementary material The online version of this article (doi:10.1007/s10682-011-9479-5) contains supplementary material, which is available to authorized users. T. Caro (&) Department of Wildlife, Fish and Conservation Biology and Center for Population Biology, University of California, Davis, CA 95616, USA e-mail: [email protected] K.
    [Show full text]
  • Foraging : Behavior and Ecology / [Edited By] David W
    Foraging Foraging Behavior and Ecology Edited by David W. Stephens, Joel S. Brown, and Ronald C. Ydenberg The University of Chicago Press Chicago & London David W. Stephens is Professor of Ecology, Evolution, and Behavior at the University of Minnesota and author, with J. R. Krebs, of Foraging Theory. Joel S. Brown is Professor of Biology at the University of Illinois at Chicago and author, with T. L. Vincent, of Evolutionary Game Theory, Natural Selection, and Darwinian Dynamics. Ronald C. Ydenberg is Professor in the Behavioral Ecology Research Group and Director of the Centre for Wildlife Ecology at Simon Fraser University. The University of Chicago Press, Chicago 60637 The University of Chicago Press, Ltd., London C 2007 by The University of Chicago All rights reserved. Published 2007 Printed in the United States of America 16151413121110090807 12345 ISBN-13: 978-0-226-77263-9 (cloth) ISBN-13: 978-0-226-77264-6 (paper) ISBN-10: 0-226-77263-2 (cloth) ISBN-10: 0-226-77264-0 (paper) Library of Congress Cataloging-in-Publication Data Foraging : behavior and ecology / [edited by] David W. Stephens, Joel S. Brown & Ronald C. Ydenberg. p. cm. ISBN-13: 978-0-226-77263-9 (cloth : alk. paper) ISBN-13: 978-0-226-77264-6 (pbk. : alk. paper) ISBN-10: 0-226-77263-2 (cloth : alk. paper) ISBN-10: 0-226-77264-0 (pbk. : alk. paper) 1. Animals—Food. I. Stephens, David W., 1955– II. Brown, Joel S. (Joel Steven), 1959– III. Ydenberg, Ronald C. QL756.5.F665 2007 591.53—dc22 2006038724 ∞ The paper used in this publication meets the minimum requirements of the American National Standard for Information Sciences—Permanence of Paper for Printed Library Materials, ANSI Z39.48-1992.
    [Show full text]
  • Optimizing Countershading Camouflage
    Optimizing countershading camouflage Innes C. Cuthilla,1, N. Simon Sangheraa, Olivier Penacchiob, Paul George Lovellc, Graeme D. Ruxtond, and Julie M. Harrisb aSchool of Biological Sciences, University of Bristol, Bristol BS8 1TQ, United Kingdom; bSchool of Psychology and Neuroscience, University of St. Andrews, St. Andrews, Fife KY16 9JP, United Kingdom; cDivision of Psychology, Social and Health Sciences, Abertay University, Dundee DD1 1HG, United Kingdom; and dSchool of Biology, University of St Andrews, St Andrews, Fife KY16 9TH, United Kingdom Edited by Raghavendra Gadagkar, Indian Institute of Science, Bangalore, India, and approved September 30, 2016 (received for review July 14, 2016) Countershading, the widespread tendency of animals to be darker rates on animals with or without the observed coloration, we on the side that receives strongest illumination, has classically cannot tell whether there is a causal effect on detectability. been explained as an adaptation for camouflage: obliterating cues Although some tests with artificial prey show reduced avian to 3D shape and enhancing background matching. However, there predation rates on two-tone, dorsally darker treatments (21–24), have only been two quantitative tests of whether the patterns the relationship between the color contrasts in these experiments observed in different species match the optimal shading to obliter- and the predicted optima are unknown. We have recently filled ate 3D cues, and no tests of whether optimal countershading this important gap by using a general theory of optimal coun- actually improves concealment or survival. We use a mathematical tershading to derive the predicted optimal patterns for different model of the light field to predict the optimal countershading for weather conditions at a specific location, time of year and day concealment that is specific to the light environment and then test (25).
    [Show full text]
  • 98Th Annual Meeting of the American Society of Mammalogists 25-29 June 2018 Kansas State University -Manhattan, Kansas
    98TH ANNUAL MEETING OF THE AMERICAN SOCIETY OF MAMMALOGISTS 25-29 JUNE 2018 KANSAS STATE UNIVERSITY -MANHATTAN, KANSAS- ABSTRACT BOOK The 2018 American Society of Mammalogists Annual Meeting logo was designed by Hayley Ahlers. It features the American bison (Bison bison), the national mammal of the United States of America, overlaid on the state of Kansas. 98TH ANNUAL MEETING OF THE AMERICAN SOCIETY OF MAMMALOGISTS 25-29 JUNE 2018 KANSAS STATE UNIVERSITY -MANHATTAN, KANSAS- AMERICAN SOCIETY OF MAMMALOGISTS (ASM) The American Society of Mammalogists (ASM) was established in 1919 for the purpose of promoting interest in the study of mammals. AN OVERVIEW In addition to being among the most charismatic of animals, mammals are important in many disciplines from paleontology to ecology and evolution. We, of course, are mammals and thus are in the interesting position of studying ourselves in quest of a greater understanding of the role of mammals in the natural world. The ASM is currently composed of thousands of members, many of who are professional scientists. Members of the Society have always had a strong interest in the public good, and this is reflected in their involvement in providing information for public policy, resources management, conservation, and education. The Society hosts annual meetings and maintains several publications. The flagship publication is the Journal of Mammalogy, a journal produced 6 times per year that accepts submissions on all aspects of mammalogy. The ASM also publishes Mammalian Species (accounts of individual species) and Special Publications (books that pertain to specific taxa or topics), and we maintain a mammal images library that contains many exceptional photographs of mammals.
    [Show full text]
  • Optimizing Countershading Camouflage
    Optimizing countershading camouflage Innes C. Cuthilla,1, N. Simon Sangheraa, Olivier Penacchiob, Paul George Lovellc, Graeme D. Ruxtond, and Julie M. Harrisb aSchool of Biological Sciences, University of Bristol, Bristol BS8 1TQ, United Kingdom; bSchool of Psychology and Neuroscience, University of St. Andrews, St. Andrews, Fife KY16 9JP, United Kingdom; cDivision of Psychology, Social and Health Sciences, Abertay University, Dundee DD1 1HG, United Kingdom; and dSchool of Biology, University of St Andrews, St Andrews, Fife KY16 9TH, United Kingdom Edited by Raghavendra Gadagkar, Indian Institute of Science, Bangalore, India, and approved September 30, 2016 (received for review July 14, 2016) Countershading, the widespread tendency of animals to be darker rates on animals with or without the observed coloration, we on the side that receives strongest illumination, has classically cannot tell whether there is a causal effect on detectability. been explained as an adaptation for camouflage: obliterating cues Although some tests with artificial prey show reduced avian to 3D shape and enhancing background matching. However, there predation rates on two-tone, dorsally darker treatments (21–24), have only been two quantitative tests of whether the patterns the relationship between the color contrasts in these experiments observed in different species match the optimal shading to obliter- and the predicted optima are unknown. We have recently filled ate 3D cues, and no tests of whether optimal countershading this important gap by using a general theory of optimal coun- actually improves concealment or survival. We use a mathematical tershading to derive the predicted optimal patterns for different model of the light field to predict the optimal countershading for weather conditions at a specific location, time of year and day concealment that is specific to the light environment and then test (25).
    [Show full text]