Sex on Six Legs

by Marlene Zuk

  No one, including Kirk, disputes that the bees also use the odor information from the initial dancer to find food, and that under some circumstances the dances are not needed for the colony members to find out where they can forage. At some times of year, the bees can find plenty of nectar by relying simply on the flower odors in their environment that are carried on the bodies of the workers that find each patch of blossoms. But when the going gets tough, the bees seem to need dancing. Some theoretical work by Madeleine Beekman and Jie Bin Lew of the University of Sydney in Australia formalized this mathematically, demonstrating that dancing helps a colony concentrate on the best food sources in the area and not waste time sending workers to a low-quality patch. It is most helpful when the probability of finding a patch on one's own as an independent forager is relatively low, because the dance allows the colony to exploit only the richest nectar sources.

  Bilingual Bees?

  WHERE did the bee dance language come from? I suggested earlier that scientists believe it may have evolved from the need to hide signals of food sources from competitors, but that problem is common to many group-living animals, not just honeybees. Which species have dance language, and how it is used, sheds light on the origin of this behavior.

  Beekman and her colleagues study dance language in the red dwarf bee of southeast Asia, which is closely related to the honeybee but nests in the open, making a single comb that is suspended from a shaded branch, rather like a wasp nest. This nesting habit is thought to be more like the ancestral state, with the elaborate cavity nests of the honeybees and several other species being more recently evolved. Dwarf bees still dance, and like honeybees, they do so both when they are selecting a new nest site and when they are feeding. But giving directions to a new nest site on a branch out in the open poses a much different problem than telling the rest of the colony how to find a small entrance hole to a cavity, such as the honeybees use. It's like the difference between telling someone to head north on State Street until he sees a big pink building—"you can't miss it"—versus giving explicit directions to a door on the third floor, east wing, of that building. On the other hand, a flower patch is a flower patch, and directions don't need to be all that precise when a worker is dancing to indicate where her nest mates can find food.

  By videotaping dances of the dwarf bees, Beekman and her colleagues found that the dances used for both food and nest site directions were equally imprecise. Honeybees, in contrast, are far sloppier when they dance to show the other workers where food is than when they are directing them to a new home. The scientists believe that the dance evolved as a way to convey information about the new nest site, and that its use to indicate food sources came later.

  If more than one species of bee uses symbolic language, can they understand each other? In a paper titled "East Learns from West," Songkun Su from Zheijiang University in China and co-workers showed that Asian honeybees, which are a different species than the European honeybees commonly found in Europe and the species that has been introduced to North America, can follow directions given by their European counterparts. Su and colleagues painstakingly constructed colonies containing a queen of one species and workers of the other, a daunting task because the specific odors of each colony usually mean the different species detect and kill any outsiders. Ordinarily the dances from the two bee species differ in what might be called dialect, with variations in the duration of the waggle portion of the dance. Su demonstrated that the two species could follow each other's directions, which means that the bees must learn some elements of the dance language.

  Bees, Chimps, and Symbols

  DESPITE the great interest in bee communication and the ever-greater elucidation of the dance, as Wenner points out, no one has ever been able to use the information to direct bees to particular crops that need pollinating or to sources of nectar that would be preferred by humans for honey production. So what is the significance of the bee dance language?

  As I have mentioned before, we seem almost obsessed with setting out criteria for membership in a club that only we can enter; humans are the only species to use tools, for example, or to routinely kill members of our own species without using them for food. Both of these turn out to be unwarranted—chimpanzees, crows, and several other animals use tools, and fig wasps, among other species, routinely slaughter their own. One can detect a certain desperation in resorting to homicidal violence as a badge of distinction, but the effort continues. And language, with its slang and poetry, has always remained a prime candidate.

  The problem is that many if not most other animals communicate, too, and they communicate in often complex and sophisticated ways. As Alison Wray put it in a book titled Language Origins, "Pinning down precisely what it is that makes human language special has never been so difficult. It's not that we no longer regard it as special, but almost every time you think you have a feature that helps define the real essence of language, or that provides a necessary context for its emergence, you seem to find some other animal that does it as well."

  When that other animal is an insect, the comparison seems particularly troubling. Eileen Crist, in an analysis of the bee language controversy, says, "This almost-serious idea of an insect with language has had an unsettling effect in behavioral science." She notes that the waggle dance satisfies the criteria of having a set of rules, with a necessary order and complexity of the symbols that are used. Psychologists Mark Hauser, Noam Chomsky, and Tecumseh Fitch declare that human language is qualitatively different from other forms of animal communication, whether birdsong or bee dances, at least if one distinguishes between what they call the faculty of language in the broad sense and the narrow sense; it isn't clear whether bees get to join at least one of those circles. Other language scholars struggle with the distinction, sometimes mentioning the auditory sensitivity that enables the nearly endless discrimination among different sounds. The idea that Washoe the chimp or Alex the African grey parrot could be taught elements of our own language makes us reexamine our uniqueness yet again.

  Just as an aside, amid all the hand-wringing and contention about whether what the bees do is really "language," no one seems to question whether it's really "dance." Maybe the dance scholars are just more easygoing than the linguists, or maybe we are already comfortable sharing that capacity with other species, though one could argue that the struts and tail shimmies of a peacock are hardly analogous to a waltz. But this points to the futility of the discussion; if we always narrow our definition of language, sooner or later we will end up with a capacity only we can possess. The breathtaking displays of a bird of paradise, or the comical movements of a lizard extending its dewlap, do not detract from the achievements of a ballerina.

  It seems to me that the bees are not much like Alex or Washoe, because we can't teach them to say "cup," or to comment on the day's activities, or ask for another piece of fruit. Bees only talk about what they need to, mainly involving food or a place to live, and I think we have gotten way too interested in the accident of their using representational movements in communicating those objectives. Bee language didn't arise from a common ancestor with humans, which means we can't see it as a primitive version of our own language. This forces us to be less anthropomorphic than we are with the primates. And the less anthropomorphic we are, the more incredible the bees' accomplishment becomes, because they evolved this system of communication with entirely different selection pressures than the ones that led to human language. How did evolution take such different paths to get to superficially similar outcomes?

  If it's true that bees needed a way to hide their communication from rivals, and that the ants' method of hauling colony members off to the new nest was unworkable for a flying insect, two other questions remain that in my mind are much more interesting than endless fussing over who does and doesn't qualify to enter the human club. The first is why all other social flying insects did not evolve some version of dance language. The second is why, when we are much more like the ants th
an the air-bound bees, we humans evolved language ourselves, rather than just dragging each other around when we wanted to convey a decision. Maybe human language isn't unique. But it beats at least one of the obvious alternatives.

  Bee language, and the complicated decisions that accompany it, exemplifies why we keep coming back to insects, why, despite their encroachment on our kitchens and sometimes our health, we can't shake our simultaneous sense of connection and distance. We all want to be able to talk to animals. With bees, as with other insects, we can be pretty sure that we will never be able to communicate with them, even to the limited extent we can communicate with our pets. Fanciful interpretations such as T. H. White's and Maeterlinck's aside, no one really believes we could get a sense of what a bee is feeling, if it has feelings at all. And yet although we can't talk to them, they seem to be able to talk to each other, in a way that can be said to be more sophisticated than the chirps and buzzes common throughout the rest of the animal kingdom. It is precisely this sense of them being more like us than anything else, with their elaborate houses, facial recognition, use of others' labor, and complicated symbols, and yet so impossibly different from the inside out, that keeps us hooked.

  Nearly a century ago, as the Jazz Age gathered steam, Don Marquis was a writer for the Evening Sun in New York. His work encompassed many topics, but he is best remembered for creating—or at least transcribing—archy, a cockroach that wrote free verse on Marquis's typewriter by laboriously crashing his head into the keys. Archy's inability to hold down the shift key led to all of his poems being written in lower case, which added a certain insouciance to his observations. The poems were first collected in 1927 and were followed by several additional volumes, with a new trove of Marquis's work discovered in 1986. The poems proved remarkably popular, coming to include commentary by the insect's friend mehitabel, "an alley cat of questionable character," as she is described on DonMarquis.com.

  Archy was generally blunt about the human condition, but he reserved some of his most trenchant observations for the role of the six-legged in the lives of the bipedal. As I have throughout this book, archy questioned the careless hubris of our assumption of superiority:

  men talk of money and industry

  of hard times and recoveries

  of finance and economics

  but the ants wait and the scorpions wait

  for while men talk they are making deserts all the time

  getting the world ready for the conquering ant

  drought and erosion and desert

  because men cannot learn

  The descendents of archy and his kind no longer seem to be leaving us missives, which seems rather a shame. Perhaps our modern keyboards seem daunting, with their need to be connected to vast processors that are inaccessible to a mere cockroach lacking both strength to turn the switch as well as a password. I would give a great deal to come into my office one day and find something like this, one of archy's best, on my monitor:

  i do not see why men

  should be so proud

  insects have the more

  ancient lineage

  according to the scientists

  insects were insects

  when man was only

  a burbling whatisit

  One can only hope that perhaps one day soon our modern cockroaches will learn to manipulate a touchpad.

  Acknowledgments

  My first thanks are owed to Bill Cade, orthopterist extraordinaire, who in addition to providing much help with my own cricket research over the years is the originator of the title Sex on Six Legs. He graciously allowed me to use it, though I am sure that his interpretation of the topic would have been at least as compelling. Other colleagues were generous with their unpublished data or manuscripts, anecdotes, and careful reading of several of the chapters: particular thanks to Nathan Bailey, Dave Featherstone, Ryan Gregory, Joan Herbers, and Kirk Visscher. Kirk has always been a great source of bee lore and other social insect information, not to mention supplying us with honey and helping us get rid of our personal swarm. Leigh Simmons has continued to be a great collaborator and colleague. Much of my love of insects as study organisms came from Adrian Wenner, who also taught me a great deal about the practice of science and its potential pitfalls. My Ph.D. advisor, the late W. D. Hamilton, was a key influence in my thinking about evolutionary biology, as well as a source of appreciation for the wonders of insect natural history. My students, graduate and undergraduate, always provide interesting comments and acted as sounding boards for many of the ideas presented here.

  My agent Wendy Strothman has been a steady support for my writing, and no one could ask for a better editor than Andrea Schulz, even if she did keep suggesting that the book contain "less sex" when I was working on the proposal. I am also grateful to several "real" science writers who have given me advice and encouragement about writing for the public: Deborah Blum, Virginia Morell, and Carl Zimmer. Finally, John Rotenberry (mostly) graciously suffers being dragged along on entomological endeavors, despite being a "bird person," and has supported me in this as in all of my efforts.

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