This is the second of a trio of reviews in which I take a brief detour into ants and collective behaviour more generally. I previously reviewed The Ant Collective, a graphical introduction to ant behaviour, and am here turning to entomologist Deborah M. Gordon’s 2010 book Ant Encounters before finishing with her recent book The Ecology of Collective Behavior. The core question driving this book is how ant colonies get anything done given that no one is in charge. Her contention, supported by a wide-ranging survey of examples, is that ant colonies function through numerous ants interacting to form a dynamic network. Stated this pithily, I admit it might not sound like much of an answer but rather a rephrasing of the question using fancy words. What do you mean, “interaction network”? If so, read on: this primer is full of fascinating biological examples and interesting insights that will hopefully clarify the above, providing you with a bigger picture of how and why ants behave the way they do.

Ant Encounters: Interaction Networks and Colony Behavior, written by Deborah M. Gordon, published by Princeton University Press in April 2010 (paperback, 167 pages)

A brief tangent to get started. Ant Encounters was the first in the then-new series Primers in Complex Systems, produced by the Santa Fe Institute in New Mexico. This is a think tank that studies complex systems in, amongst others, biology, physics, sociology, and computer sciences. Next to a small cadre of resident researchers, they host a rotating cast of visiting academics and provide an environment for cross-disciplinary research, discussion, and exchange of ideas. Some other books I have reviewed here have been the product of, or at least been helped along by, time spent here. Seven books have been published so far in this series, though there have been no new additions since 2019. If this first book sets the tone, these are very interesting and accessible little books that are worth checking out and I have listed them below. Anyway, back to Gordon and ants.

This book follows her popular book Ants at Work published another decade earlier in 1999. At the time of writing Ant Encounters, Gordon had already been studying ants for some three decades, since the early 1980s, mostly the desert-dwelling red harvester ant Pogonomyrmex barbatus. Her work and ideas formed in response to the then-prevailing view that ants are effectively genetically programmed to perform particular tasks. Her early work instead found that what ants do depends on interactions with other ants, which in turn can modify their environment, which in turn can feed back on subsequent interactions, etc. In other words, the behaviour of colonies arises from dynamical, constantly shifting networks of interactions. (The Ant Collective neatly showed in pictures how this works in the waxing and waning of a foraging trail.) After introducing this concept in the first chapter, the remaining six chapters flesh it out with numerous examples at different levels of biological organization.

A logical first question to ask is what ants actually do when they meet. A lot of feeling each other up is what. Communication in ants is firstly tactile, with ants using their antennae to touch each other (entomologists speak of antennation). One of Gordon’s key points is that “the pattern of interaction itself, rather than any signal transferred, acts as the message” (pp. 47–48). Experiments in harvester ants showed that what stimulated foragers to leave the nest was the encounter rate with patrollers returning in the morning. One question for Gordon I was left with was whether smell acts as a message. After all, a second important channel is chemical, with ants, like many other insects, carrying hydrocarbons (so-called cuticular hydrocarbons) on their exterior. These serve as an identity badge but also change during tasks: Gordon’s work on harvester ants showed how ant odour changes as they go outside e.g. to forage. Interestingly, there is individual variation in how active ants are but this is not fixed. Remove particularly active ants and others will take up their workload; there are no “forager heroines” (p. 66).

“A logical first question to ask is what ants actually do when they meet. A lot of feeling each other up is what. […] One of Gordon’s key points is that “the pattern of interaction itself […] acts as the message“”

Scaling up a little to the level of local interactions, Gordon objects to the idea of “division of labour” introduced by famed entomological titan E.O. Wilson. He happened to study some of the few ant species where workers have different body sizes and tried to demonstrate that there was a caste system with size-based task specialisation. Though partially successful, even here individual behaviour changes as needed, with e.g. removal of minors (small ants) causing larger majors to switch to brood care. More importantly, Gordon adds, in most ant species workers are of similar size. Whereas “division of labour” implies static procedures and permanently assigned roles, her preferred term “task allocation” highlights the dynamic, flexible nature of ant behaviour. A related idea that is scrutinized is age polyethism: tasks changing as a function of age. I encountered this in Tschinkel’s book Ant Architecture and though young ants are indeed born in the depths of the nest, the idea that they move up with age and get “promoted” to brood care, nest construction, and finally foraging is more often proposed than backed up with data in the published literature. Experiments on carpenter ants showed that if one age group was removed, others would take over their tasks, suggesting that colony needs override ant age.

Speaking of age, colonies are not static entities and, though there are very few studies on this, colony growth influences behaviour. Particularly important are ant-plant interactions with ants defending host plants from herbivores, thus stimulating plant growth, which in turn begets a larger colony (a nice example of niche construction if ever there was one). In many such mutualisms, there is a third party such as scale insects or aphids that feed by sucking a plant’s sap but are vulnerable to predators. Ants protect them in exchange for the sugary honeydew these sap-suckers excrete from their anuses. The plants tolerate the sap-suckers because the ants thus attracted protect against more harmful herbivores. Ecologist Robert May is quoted as describing such three-way interactions as “an orgy of mutual benefaction” (p. 124).

Scaling up further brings Gordon to the level of inter-colony interactions, both conspecific (between colonies of the same species) and heterospecific (between colonies of different species). Interactions are both direct, e.g. encounter rate with neighbours indicating the size of their colony, and indirect, e.g. competition for food being a zero-sum game: what one colony eats is not available to the other. Bar some spectacular exceptions, fighting between conspecifics is usually avoided. In response to neighbourly interactions, harvester ant patrollers will redirect the next day’s foraging trails. When it comes to heterospecific interactions, conflict has been better studied and Gordon highlights the rise of invasive ant species in the last three decades as another opportunity to do so. In general, numerical advantage trumps body size, with small-bodied species capable of simply swarming larger-bodied ones. A further, delightful level of interaction is between ants and the organisms living in their midst (so-called myrmecophiles) that I discussed at length when reviewing The Guests of Ants.

“In many ant-plant interactions, there is a third party involved, such as scale insects or aphids, in what has been described as “an orgy of mutual benefaction“”

The final level Gordon considers is that of evolution. How did colony organization evolve from ancestors that did not live in colonies? In particular, as workers are unable to reproduce, how did worker sterility evolve? W.D. Hamilton linked it to the haplodiploid mating system of ants where males hatch from unfertilized eggs and carry a single set of chromosomes (haploidy) while females hatch from fertilized eggs and carry the regular two sets of chromosomes (diploidy). One quirk of this system is that, if a queen mates with only a single male, females are more related to their sisters than to their daughters, with kin selection maintaining worker sterility once it somehow arises. The fly in the ointment that Gordon points out is that many queens mate with several males, so Hamilton’s maths quickly unravels, leaving the mystery of worker sterility intact. (In Endless Forms, Sumner explores this story more in-depth, showing there are other reasons why Hamilton’s explanation does not work). What we do know is that ants evolved from vespoid wasps, themselves a case study in the evolution of sociality. Interestingly, worker sterility has evolved many times in wasps and shows more flexibility, with wasps able to become egg layers when needed, arguing against a sudden mutation being responsible for worker sterility in ants. The matter remains unresolved, but Gordon does think that describing social structure in terms of who lays the eggs is “misleading language [that] equates the allocation of egg-laying with social organization and directs attention away from everything else that makes up the diverse and complex social organization of ant colonies” (pp. 130–131).

If all of the above left your head spinning somewhat, then you are not alone. There are some really interesting challenges to established ideas in this slim book, but it took some effort to distil these key points. Much as was the case for The Guests of Ants, this book presents a bewildering variety of examples from many different species, reflecting the state of play in myrmecology. A recurrent theme is that we have extremely limited data. Of the approximately 11,000 ant species known to exist, only 50-odd have been studied in any detail and even then only in fragmentary fashion. “What we have so far are only some of the pieces of many different puzzles; fragments of the picture for army ants, other pieces for harvester ants, others still for fire ants, and so on” (p. 144). Even in this limited sample, exceptions and diversity abound. A brief final chapter considers what it would take to construct models of ant behaviour. This would come to occupy Gordon for the next decade, resulting in the recent publication of The Ecology of Collective Behavior to which I will turn next.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Ant Encounters

Other recommended books mentioned in this review:

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Princeton’s Primers in Complex Systems:

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It has to be one of the more delightful details of the natural world: the ecosystem of an ant’s nest is home to its own constellation of creatures that specialise in living within or nearby it. Daniel Kronauer’s book Army Ants first drew my attention to these so-called myrmecophiles and their sometimes bizarre adaptations. I was stoked when Harvard University Press announced it would publish a monograph focusing on just this aspect of ant biology, authored by entomology professors Bert Hölldobler (a frequent co-author to E.O. Wilson) and Christina L. Kwapich. The Guests of Ants gives a beautifully illustrated, wide-ranging, and critical literature review of this delightful corner of myrmecology. Will ants make it to my personal top 5 for a third-year running? This book is a very strong contender.

The Guests of Ants: How Myrmecophiles Interact with Their Hosts, written by Bert Hölldobler and Christina L. Kwapich, published by Belknap Press (a Harvard University Press imprint) in July 2022 (hardback, 559 pages)

Before delving in, a quick word on what is not in the book. Excluded are the large topic of interactions between ants and plants, the subject of trophobiosis (i.e. the bugs and some butterflies that provide honeydew to ants and in return are protected by them), and the hundreds of socially parasitic ant species that exploit other ants^[1]. This book is also not an exhaustive listing of all known myrmecophiles, as done in review papers and books such as Parasites in Social Insects and The Ants. Instead, Hölldobler & Kwapich use numerous examples to review the behavioural mechanisms by which myrmecophiles coexist and often exploit their hosts. How do they break the internal communication codes that otherwise make ants such a successful superorganism? This self-imposed limitation nevertheless leaves plenty of material and the first thing that will strike you is the book’s sheer size. Measuring some 24 × 24.5 cm it is as big as Army Ants, though it is a good deal thicker. What it shares is that it is chock-a-block with glorious macro-photography. The acknowledgements thank no fewer than 84 people for providing (mostly) photos and illustrations and the book is a feast for the eyes.

So who are these guests? Beyond two chapters on the really small (bacteria, internal parasites, and fungi such as crowd-pleaser Ophiocordyceps) and the really large (vertebrates including birds, lizards, and amphibians), most myrmecophiles are arthropods. Some flies and beetles rely on chemical mimicry to blend in and e.g. hitch a ride on ant bodies, lay their eggs inside the protected environment of ant nests, or forage here for detritus and ant corpses. Caterpillars of lycaenid butterflies possess glands that secrete so-called appeasement substances, allowing them to live amidst ants as mutualists, parasites, or even predators. Refuse sites inside the nest, and foraging trails outside it, host numerous beetles and flies that steal booty and prey the ants bring home, or attack the ants directly. Crickets behave as thieves, technically as kleptoparasites. Using a mixture of chemical stimuli, such as odours, and tactile stimuli, such as antennae and mouthparts with which they tickle ants, they either get ants to regurgitate liquid food for them (as seen on the book’s cover) or get in between two ants practicising what biologists call trophallaxis, the transfer of food between each other. But the most mind-blowing chapter showcases the unbelievable morphological and behavioural mimicry of certain spiders. Some spiders, as they grow larger, resemble different ant species in turn. Other spiders use parts of their body such as chelicerae (mouth parts) and fold these in front of their heads to resemble an ant carrying a nestmate.

“Hölldobler & Kwapich use numerous examples to review the behavioural mechanisms by which myrmecophiles coexist and often exploit their hosts.”

The above is just a small selection of a mind-bogglingly diverse cast of myrmecophiles. Two further chapters focus more on underlying explanations. One looks at a possible evolutionary pathway that explains how free-living insects became fully integrated into ant nests, illustrating it through studies on different rove beetles. The other chapter looks at various ant ecosystems and their guests, including harvest ants, wood ants, and army ants. It also discusses studies that have tried to apply network analyses to document foodweb interactions (i.e. myrmecophiles eating ants and each other), and studies that have looked at links between colony traits, such as genetic diversity, and rates of myrmecophile infestation.

A few things struck me in particular about this book. First is the amount of detail. The authors thoroughly show just how diverse are myrmecophiles and the ways in which they trick ants. If I have to sound a critical note, it is that, though the individual chapters are organised around themes, I was missing a final chapter to tie it together and provide some sort of overview or tabulation. The bewildering diversity, fascinating as it is, now remains just that: bewildering. But perhaps that is the nature of the beast. Second was a fascinating lesson on cuticular hydrocarbons. These are carbon-and-hydrogen-containing chemicals that insects sport on their outer layer, their cuticle, as a kind of chemical signature. You would think that mimicking or acquiring cuticular hydrocarbons is key for myrmecophiles to be accepted or ignored by ants, rather than attacked and killed. But numerous studies have thrown up conflicting results: “we have to guard against a hasty conclusion that the hydrocarbon match represents the effective mechanism for the acceptance of myrmecophiles by their hosts” (p. 147). Other chemicals as well as behaviour seem to play an overriding role in some species. Third and final was a welcome critical attitude from the authors in their review. They frequently point out shortcomings in experimental protocols, comment on the appropriateness of certain methods, and tone down sweeping conclusions. None of this is mean-spirited but is done to encourage rigorous experimental protocols. The ecosystem of ants and their guests is incredibly complex and studying them is hard; drawing firm conclusions requires excluding alternative explanations.

The Guests of Ants is a must for myrmecologists and entomologists, but also more generally for biologists with an interest in social insects and insect ecology. The book provides a welcome entry point into a remarkably rich literature (45 pages of references are provided). The work is detailed and fairly, but not overtly, technical; effectively this is at the level of a series of literature reviews as one might find in e.g. Trends in Ecology & Evolution. There is nothing here that avocational entomologists or an interested lay audience could not handle, with a 14-page glossary taking care of technical terms. For my part, I have to congratulate the publisher for producing yet another exquisitely presented, in-depth monograph on ants that highlights a thoroughly engrossing aspect of these fascinating insects.

1. ↑ Regarding that last group, the authors write that “this is an exciting field in evolutionary myrmecology, which awaits coverage in a separate volume” (p. 479). Oh my, should I interpret this as them saying this deserves a dedicated book, or, more tantalizing, that this is something they are working on? How exciting would that be!

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

The Guests of Ants

Other recommended books mentioned in this review:

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If ants give you the heebie-jeebies, you will want to turn away now, for this book review will deal with the ultimate arthropod nightmare: army ants. If, however, insects are your shtick, stick around, because German entomologist Daniel Kronauer has written a phenomenal book on army ant biology that is chock-a-block with jaw-dropping, award-winning photography.

Army Ants: Nature’s Ultimate Social Hunters, written by Daniel J.C. Kronauer, published by Harvard University Press in October 2020 (hardback, 368 pages)

Ants have been getting under my skin lately. The more I read about ants, the more I want to read about ants. This year, fortunately, Harvard University Press has spoiled myrmecophiles—of the human kind, that is. After Desert Navigator in February, Army Ants is the second big book on ants for 2020. These social insects, cooperatively hunting in swarms of up to millions of individuals strong, epitomise the unstoppable force of nature. But this fearsome reputation hides a truly fascinating story of evolution, collective behaviours, and unlikely insect alliances.

Kronauer has set himself a challenging task with Army Ants. On the one hand, he aims to provide a successor to the books by Theodore Schneirla (1971) and William Gotwald (1995), incidentally both also called Army Ants. There are many new findings from fieldwork and the application of molecular genetic tools that should interest professional entomologists. On the other hand, he wanted a book geared towards a more general audience. And he has certainly struck the right balance. Rather than an exhaustive army ant encyclopaedia, Kronauer focuses on two closely-related species, Eciton burchellii and Eciton hamatus, that he has extensively studied at La Selva Biological Station in Costa Rica. Still, plenty of other army ant species feature here in detail.

The book starts with a history of both the discipline and the species. The discovery of army ants takes the reader back to the 1700s, to the first depictions by famous naturalist and artist Maria Sibylla Merian and subsequent studies by e.g. Mutis, Fabricius, Latreille, Darwin, Wallace, Bates, and William John Burchell after whom E. burchellii is named. The story of their evolution is the story of eusociality: the extreme form of social living where the many forego reproduction so that the few become specialised egg-laying machines, and the whole functions as a superorganism. In particular, it is the story of the ant subfamily Dorylinae, which contains most army ant species.

“amidst all the social insects […] three closely connected traits […] make army ants unique: mass raiding, nomadism, and colony fission”

At the core of Army Ants lies the question of what, amidst all the social insects, makes them special? This is where the book gets really interesting and details the three closely connected traits that make army ants unique: mass raiding, nomadism, and colony fission. Or, as Kronauer puts it plainly: “hunting in massive groups, frequent relocation of the nest, and multiplying by splitting large colonies”.

I will be honest with you, I was spellbound by these three chapters and can only give you a taster here of why army ants are so fantastically fascinating. But consider the anatomy and dynamics of swarm and column raids, the emergence of living architecture when workers link their bodies together to provide bridges and bivouacs for their nestmates, or the many animals that systematically follow army ants to prey on the creatures flushed out into the open when a swarm approaches. Think of the nomadic lifestyle that means regular and complete relocation of nests—eggs, larvae, and everything else included. Add to that the extra layer of complexity that sees colonies oscillate between nomadic and settled (statary) phases in parallel with the reproductive cycle of the egg-laying queen. Or what of the rarely observed phenomenon of colony fission where new colonies are founded by one colony splitting up.

And the book does not run out of steam towards the end either. A final chapter explores the many (many!) insects and other organisms that have made an unlikely home inside or nearby army ant colonies, how they manage not to get eaten alive, and how they have adapted to a nomadic host. Kronauer introduces a veritable travelling circus of evolutionary adaptations that beggars belief.

“let me just point out the exquisite pictures, [Army Ants contains] some of the finest insect photography you will see this year.”

Whereas a book such as Desert Navigator was information-dense and, in places, technical, Kronauer presents his overview of army ant biology in an easy-going, narrative style that only occasionally descends into the nitty-gritty, e.g. when discussing colony fission in the context of inclusive fitness theory. As such, he can get away with including only a handful of infographics and data tables—his clear delivery does not require more. An extensive glossary helps clarify discipline-specific terminology. Simultaneously, his broad overview of the literature and the numerous citations point the reader to all the details in case you want them.

Now, if that was not enough to convince you to read this book, let me just point out the exquisite pictures, for Kronauer is also a gifted photographer. His shot of an army ant bivouac won him the award in the “Insect Behaviour” category of the Wildlife Photographer of the Year 2019 competition, and he contributed virtually all the photos here. From jaw-dropping pictures taken in the field to phenomenal close-ups in the studio, this book will show you ants in ways you have never seen them before. A nice bonus is that in the figure legends Kronauer can provide unique information on how certain photos were taken.

I was really looking forward to this book when it was announced earlier this year and it far surpassed my expectations. Kronauer writes of army ants in a skilful and reader-friendly way and accompanies it by some of the finest insect photography you will see this year. This is a superb book that will take pride of place on your bookshelf.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Army Ants

Other recommended books mentioned in this review:

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When we think of animal navigation, the dramatic comes to mind: globe-trotting birds, migrating monarch butterflies, and ocean-crossing whales. But on a smaller scale, navigation is no less vital and no less interesting. Take the humble desert ant. Desert Navigator is the culmination of a lifetime worth of study by German zoologist Rüdiger Wehner and his many collaborators. It is an astonishing and lavishly produced book that distils half a century of experiments into a richly illustrated narrative.

Desert Navigator: The Journey of an Ant, written by Rüdiger Wehner, published by Belknap Press (a Harvard University Press imprint) in February 2020 (hardback, 392 pages)

Unless you live in a desert environment, chances are that you have never seen a desert ant. Speedy silver bullets that dart across the sand on long legs, ants of the genus Cataglyphis (cataglyphs to you and me) live in the deserts of North Africa, the Middle East, Europe, and Asia. In a beautiful example of parallel evolution, the deserts of Southern Africa are host to the genus Ocymyrmex, while the Australian outback is home to Melophorus ants. Wehner calls them little thermal warriors, as they stand out for their thermophile (heat-loving) behaviour. When pretty much every other living creature tries to find shade, these ants come out at the hottest part of the day to forage in murderous temperatures, tolerating surface values of 57-63°C.

How do they survive such extremes? Wehner appropriately opens the book with an introduction to the biology of desert ants. Here, he details their morphology and behaviour, highlighting how they cope with the heat through for example a thermal shield of silvery hairs that covers parts of their body, clever use of small-scale temperature variations just above ground level, and careful prevention of dehydration. Speed is of the essence to get the most out of their foraging trips, so Wehner examines their locomotion and long-leggedness.

Navigation, however, is at the core of this book. Given that their nest opening is but a small hole in the ground and there is a high price to pay for getting lost, how do these ants navigate such barren and featureless environments? How do they, without fail, find the shortest way home after having wandered about in search of food?

“When pretty much every other living creature tries to find shade, these ants come out at the hottest part of the day to forage in murderous temperatures, tolerating surface values of 57-63°C”

To answer these questions, the book takes a tour through five decades of experimental work, regularly venturing into research on related insect groups and covering a large body of older research published in German. What stands out is just how far you can take various lines of inquiry in that amount of time. Desert Navigator is not a difficult book to read, but it is information-dense. Every section, sometimes every paragraph, summarises a different study. To avoid vague or hasty conclusions, Wehner stresses the importance of careful experimental design and the field biologist in me delighted in the many unusual contraptions and clever solutions to answering questions. In what follows, I can only cover some examples of particularly memorable findings.

Tiny as they are, Wehner shows these cataglyphs to be miracle insects. This starts with the diversity of environmental cues they use to find their way: polarized light* (something humans cannot perceive, but many animals can), gradients in both the intensity and spectrum of light that indicate the azimuth or compass bearing of the sun, the earth’s magnetic field, even wind direction. Just as humans focus images on a tiny pit in their retina called the fovea, the compound eyes of insects have specialised areas too. Blocking different parts of ant eyes has revealed how the dorsal rim area (found towards the top) is both necessary and sufficient to observe polarized light. And we can even trace how this is processed in the brain. Ant brains are incredibly tiny, but certain neurological architecture and pathways are conserved across the family tree of arthropods, so work on the larger crickets and locusts has been enlightening.

Finding your way home involves having a sense of distances. Ants employ an internal step counter and measure optic flow, the speed with which your environment moves past your eyes as you move. This has involved ingenious experiments lengthening (with stilts) or shortening (poor buggers) ants’ legs, or manipulating optic flow using striped conveyor belts, resulting in ants overshooting or undershooting their nest when returning. Why do ants use both? Wehner argues the latter could be an evolutionary hangover as ants are related to flying hymenopterans that use optic flow rather than a step counter to estimate distances.

“To avoid vague or hasty conclusions, Wehner stresses the importance of careful experimental design and the field biologist in me delighted in the many unusual contraptions and clever solutions to answering questions.”

Combining distance and direction is known as path integration or dead reckoning. Picking apart this process has involved allowing ants to walk to a feeder and then catching and releasing them elsewhere. They will walk back the right distance in the right direction to where their nest should be. Further work with ants walking part of their route through tunnels showed that only steps taken under an open sky count when calculating the return route though. But ant navigation also incorporates visual landmarks (most likely the general appearance of an ant’s panoramic view), and olfactory cues (the smell of the nest in particular). Young ants have been shown to go on learning walks and do visual scanning maneuvres to observe their nest from various angles. Here, too, further work has tried to link this to brain regions, with the so-called mushroom bodies being likely candidates for the long-term storage of landmark information.

Researchers have even started probing how these systems come together and interact. Presenting ants with conflicting information by moving familiar landmarks leads to compromise trajectories between what path integration and landmark views tell them, while further work shows landmark recognition to become more important closer to the nest. Ants will even employ error correction strategies by purposefully undershooting their target or navigating downwind of nest odour plumes.

Mammals seem to build a mental map of their surroundings, but insects? While some have claimed bees do, Wehner and others contest this, arguing that combining several routines is sufficient for successful navigation. As he puts it succinctly, ants know where to go without necessarily knowing where they are.

“Mammals seem to build a mental map of their surroundings, but insects? [Wehner argues that] ants know where to go without necessarily knowing where they are.”

A highlight of this book are the full-colour illustrations. Text and images complement each other perfectly: you need one to understand the other. No fewer than three graphic designers are credited in the acknowledgements, hinting at the staggering amount of work involved. The vast majority of illustrations have been redrawn from roughly 100 different scientific publications, covering five decades. This will have included everything from hand-drawn illustrations in the early days to those produced with graphic software recently. Had these been reproduced as is, which happens, the mixture of visual styles would have been jarring. Now, the book is presented in such a smooth, uniform style that it almost goes unnoticed, so this is a point of praise worth reiterating.

After Wilson’s and Hölldobler’s book The Ants in 1990 and Tschinkel’s The Fire Ants in 2006 (and with Army Ants also published in 2020), this title joins what is becoming an illustrious line-up of in-depth books on ants published by Harvard University Press. I praise them unreservedly for the lavish production values they have heaped upon it. Desert Navigator is a myrmecological masterpiece and a fitting milestone in Wehner’s long and successful research career. If you have any interest in ants, insect behaviour, or animal navigation you absolutely do not want to skip this astonishing book.

* Since we cannot perceive polarized light, a short explanation is called for. When emitted by the sun, travelling light waves can oscillate up and down, or side to side, or really any angle in between. When light enters the atmosphere and water bodies, it scatters. Air and water molecules filter out waves with certain oscillation directions, leaving only waves oscillating in other directions. The result is called polarized light.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Desert Navigator hardback or ebook

Other recommended books mentioned in this review:

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