Desert Navigator: The Journey of an Ant

401 Pages·2020·20.993 MB·English

by  Rüdiger Wehner

desert navigator

Desert Navigator
THE JOURNEY OF AN ANT
Rüdiger Wehner
the belknap press of harvard university press
Cambridge, Mas sa chu setts, and London, England 2020
Copyright © 2020 by the President and Fellows of Harvard College
All rights reserved
Printed in Canada
First printing
Cover art: Cataglyphis bombycina, the silver ant. © Rüdiger Wehner
Cover design: Annamarie MacMahon Why
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The Library of Congress has cataloged the printed edition as follows:
Names: Wehner, Rüdiger, author.
Title: Desert navigator : the journey of an ant / Rüdiger Wehner.
Description: Cambridge, Mas sa chu setts : The Belknap Press of Harvard
University Press, 2020. | Includes bibliographical references and index.
Identifiers: LCCN 2019015093 | ISBN 9780674045880 (hardcover)
Subjects: LCSH: Ants— Be hav ior— Sahara. | Animal navigation. | Neural circuitry.
Classification: LCC QL568.F7 W427 2020 | DDC 595.79/6156— dc23
LC rec ord available at https:// lccn . loc . gov / 2019015093
For Sibylle

Contents
Prologue 1
1 Setting the Scene 5
2 The Thermophiles 25
3 Finding Directions 91
4 Estimating Distances 149
5 Integrating Paths 171
6 Using Landmarks 201
7 Organ izing the Journey 263
Epilogue 303
Notes 311
Acknowl edgments 377
Illustration Credits 381
Index 389

Prologue
It is certain that there may be extraordinary mental activity with an extremely small absolute mass
of ner vous matter: thus the wonderfully diversified instincts, mental powers, and affections of ants
are notorious, yet their ce re bral ganglia are not so large as the quarter of a small pin’s head. Under
this point of view, the brain of an ant is one of the most marvelous atoms of matter in the world,
perhaps more so than the brain of a man.
Charles Darwin, 1871
This book is about an oriental beauty, an elegant, long- legged, extremely speedy
ant. It strikes the eye immediately when one wanders about in the Sahara or in any
other Old World desert. I became fascinated by this remarkable ant— Cataglyphis by
name— half a century ago, and my fascination has never ceased. Besides its con-
spic u ous stature, running style, and extraordinary love for the blazing desert heat,
it is the superb means of finding its way on far-r anging foraging journeys across
large expanses of barren land that continues to astound me.
Over several de cades dozens of highly motivated and talented gradu ate stu-
dents have shared my fascination in unraveling the navigational repertoire of these
little desert dwellers. Moreover, species of some other genera of ant, Ocymyrmex and
Melophorus, which inhabit the deserts of southern Africa and central Australia, re-
spectively, and resemble Cataglyphis in foraging style, heat re sis tance, and navi-
gational skills, have joined us, as have colleagues from vari ous research schools all
over the world. The Danish physiologist and Nobel laureate August Krogh once re-
marked that “for a large number of prob lems there will be some animal of choice,
or a few such animals, on which it can be most con ve niently studied.”1 For vari ous
reasons, which will become apparent in this book, Cataglyphis is an ideal model
organism for studying prob lems of animal navigation.
A foraging cataglyph may leave its under ground nest for distances of several hun-
dred meters, i.e., for more than 10,000 times its body length. It does so completely