By Fernando Racimo, thurj Staff
Edward O. Wilson once proclaimed: “Karl Marx was right, socialism works, it is just that he had the wrong species.” The renowned American biologist has dedicated his life to studying the organisms that would have made the German philosopher proud: ants, bees and termites – the stalwarts of social living. Wilson’s new book, The Superorganism– co-authored with the biologist Bert Hölldobler – seeks to unravel the mysteries of insect eusociality: a social system that in many ways surpasses human societies in its complexity and cohesion.
The book begins by giving an evolutionary survey of the origins of eusociality before transitioning into an extensive ecological account of the inner workings of a variety of insect colonies. The last chapters are devoted to analyzing the most extraordinary displays of eusociality, like fungi agriculure in leaf-cutter ants and the giant structures built by African termites to house their brood.
What exactly is eusociality? As the authors make clear, eusocial colonies generally possess three defining characteristics: cooperative care of the young, overlaps between generations of individuals, and reproductive castes. The last feature implies that some members of the group (workers and soldiers) forfeit their individual right to reproduce in order to dedicate more amounts of time, effort, and resources to taking care of the brood and of those individuals who do get to reproduce – either one queen or a group of them, depending on the species under study.
But unlike what Marx had in mind, eusociality has no room for centralized planning. Wilson and Hölldobler aim to show that there is no central administrator inside a bee hive or a termite mound: the queen is too busy producing eggs and the workers are too busy, well, working. Therefore, planning comes about as an emergent property of each individual’s perceptions and actions. But how do thousands of insects with brains smaller than the tip of a needle manage to coordinate and exchange so much information?
The book dedicates an entire chapter to the many forms of eusocial communication, another to the development of simple decision rules associated with different inputs of information, and another to the interplay of communication and information in determining castes and allowing for cooperative teamwork to gather resources or attack neighboring colonies. Wilson and Hölldobler have an ability to make complex biology seem like a piece of cake, and that ability is at their best in these three chapters. From long-lasting chemical trails to alarm pheromones, the processes that underlie the exchange of information between workers, soldiers and queens are detailed with true mastery. They emphasize how little science has revealed about eusocial communication and how much more remains to be discovered. Their one flaw in this analysis is perhaps their overly narrow focus on ant communication, while saying little to nothing about communication in bees, termites or other eusocial insects, like aphids and thrips. This is, nevertheless, justifiable given how much is known about ants (especially because of the author’s own scientific contributions) and how little is known about other colonial organisms.
Though efficient mechanisms for communication allow the colony to maximize its energy input and reproductive output, eusociality also entails a measure of internal conflict. Chances are that Marx would have been slightly disappointed, even if he had applied his sociopolitical theories to the world of ants and termites. In fact, some female worker ants mutilate their brother’s wings to prevent them from mating with other queens; workers may also kill queens who recognizably do not possess the gene that causes the killing in the first place. Conflict indeed permeates what seems like a cohesive system from an outsider’s viewpoint.
In fact, there is so much conflict inside certain colonies that the word “superorganism” may not exactly be the right way to describe a eusocial colony. All of the cells in an organism’s body carry the same versions of each gene, so it is extremely unlikely that a group of cells will try to harm any of the other cells. They are all in for the ride, and they all privilege the survival and reproduction of the organism above anything (cancer and autoimmune diseases are rare exceptions). Genes need to cooperate in order to be passed on to future generations.
Yet this is not exactly the case in the eusocial kingdom: parents, siblings and offspring are not exact copies of one another and the levels of relatedness between each other – though uncommonly high – are not exactly as high as those between the cells in our body. The authors show many examples of the chaos that sometimes ensues when a queen dies and the foundations of colonial hierarchy begin to shake. Usually, communication and agonistic rituals prevent widespread violence. Grabbing a subordinate’s antennae and shaking them, for example, constitutes a display of superiority in contests for power and prevents subordinates from continuing its attempts at climbing the social ladder (biology shows that bullying is by no means limited to high school corridors). But conflict may go much farther than bullying. In ponerine ants, as the queen gets old and weak, some workers (called gamergates) acquire the ability to reproduce. Once they are recognized by other workers as reproductives, they are also able to mark other potential gamergates with a chemical. The signal effectively activates policing behavior in workers, which proceed to spread-eagle and often kill the potential gamergates who dare defy the reproductive right of the already established gamergates.
Given such high degrees of cooperation, conflict and communication, there is one central issue that the book addresses poorly: how did it all came to be that way? Wilson and Hölldobler make use of multilevel selection theory to explain the origins of eusociality. Multi-level selection theory is the idea that altruistic traits are naturally selected in the course of evolution because they benefit a group of individuals as opposed to the individual members of the group. So long as the group has low intra-group genetic variance (members are more related to themselves than to outsiders), the trait will be selected and become widespread. Thus, certain behaviors and communication mechanisms in ants must – according to Wilson and Hölldobler – have evolved because they were advantageous to the group. Their argument seems to run opposed to inclusive fitness theory: the idea that traits can be selected not just because they benefit an individual’s offspring but also because they benefit close genetic relatives who have a high probability of carrying the same genes as the individual with the traits. For Wilson and Hölldobler inclusive fitness theory is not a sufficient explanation for eusocial behavior. It is thus necessary to use multilevel selection theory to explain some aspects of eusociality. And they stress this point in repeated instances throughout the book from the division of labor to self-imposed restrictions to reproduction.
The problem with this approach is that, as many scientists are now realizing, multilevel selection is just another side of the coin of inclusive fitness theory. Both theories are accurate because, in reality, both are just two equivalent methods of explaining the same mechanism. Stating that altruistic group traits are selected when group members are closely related to each other is just another way of saying that altruistic individual traits will be selected when they are directed towards close kin. Even Wilson and Hölldobler admit to this point at the very beginning of their book: “It is important to keep in mind that mathematical gene-selectionist (inclusive fitness models) can be translated into multilevel selection models and vice-versa.” And yet they don’t seem to apply their own realization to the rest of the book: the authors repeatedly make the distinction between the two theories as if they were separate processes, creating confusion as to what exactly they mean when they refer to the evolution of eusociality.
Despite the sloppiness of the book when describing evolutionary phenomena, its elegance and clarity when it comes to physiological, organizational and ecological processes are unmatched. Not only do the authors succeed at making the reader understand how dynastic succession affects the overarching dynamics of the eusocial kingdom or how recruitment to new nest sites occurs over time, they also make sure the reader ‘sees’ these and many other behaviors in vivid photographs and illustrations. An example is the image of a group of weaver ants forming a “living bridge” with their own bodies to pull leaves together, which truly enlivens Wilson and Hölldobler’s narrative of nest construction.
Overall, The Superorganism constitutes a comprehensive analysis of a complex biological system by two masters in the field. But more than that, it is also a telling account of a social world that is highly distinct from human societies and yet has managed to thrive during millions of years of evolutionary struggle. Both of its authors have studied these creatures for decades and, through this book, they make a compelling case for the value of this knowledge and the many questions that still remain unanswered. Ants, bees and wasps do not live in communist utopias. Nevertheless, their extraordinary ability to cooperate with one another and carry out coordinated enterprises by the millions is something Marx would have definitely envied.