Letters to a Young Scientist by Edward O. Wilson Page B

set in resin only a few days earlier.
    My collaborators and I named the Mesozoic ant Sphecomyrma freyi , the first generic name meaning “wasp ant,” and the second in honor of the retired couple who had found the specimens. The generic name was fully justified: the species had a head that was mostly wasplike, some parts of the body were mostly antlike, and other parts of the body were intermediate in form between wasps and ants. In short, the missing link had been discovered, another grail found.
    The announcement of the discovery set off a flurry of new searches by entomologists for ants and antlike wasps in amber and sedimentary rock deposits of late Mesozoic age. Within two decades many more specimens turned up in deposits from New Jersey, Alberta, Burma, and Siberia. In addition to more Sphecomyrma , new species at other levels of evolutionary development came to light. The story of the early diversification of the ants began to unfold. We found that it reaches back at least 110 million years and probably well beyond, to as far as 150 million years before the present.
    Yet, sadly, we still had only fossils. No living evolutionary links had been found whose social behavior could be studied in the field and laboratory. It appeared that direct knowledge of the early stages of social behavior in the ants might have to be pieced together indirectly. The Australian dawn ant and a small number of other comparably primitive lines among the living ants might prove the best that would ever be found.
    Then in 2009 came a complete surprise with at least the potential to change the big picture. A young German entomologist, Christian Rabeling, was excavating soil and leaf litter in rain forest near Manaus, in the central Amazon. Rabeling, with whom I’ve since worked in the field, has the deserved reputation of leaving, literally, no stone unturned. He also readily climbed trees, unaided by equipment, to bring down ant colonies nesting in the canopy. One day, as he was picking up every new kind of ant he could find, he spotted a single pale, odd-looking specimen crawling beneath the fallen leaves. Picking it up, he realized that he could not place it to any known genus or species of ants.
    During a visit to Harvard he brought his discovery along with the rest of his collection to the “Ant Room.” Here, in cramped quarters on the fourth floor of Harvard’s Museum of Comparative Zoology, is kept the largest and most nearly complete classified collection of ants in the world. Built up by a succession of entomologists over more than a century, it contains perhaps a million specimens (no one has volunteered to make an exact count), belonging to as many as six thousand species. Ant experts from around the world come to these quarters to identify specimens they have collected on their own, and to conduct research on classification and evolution. Several were present when Rabeling brought in his Amazonian oddity.
    After much consternation, the group invited me in from my office across the hall. I remember the moment vividly. Taking a look under the microscope, I said, “Good God, this thing must be from Mars!” Which meant I didn’t have a clue either. Later, when Rabeling described the species formally in a technical journal, he gave his ant the name Martialis heureka , which means, roughly, “the little Martian that has been discovered.” It was an ant, all right, and proved an earlier branch in the ant family tree than even the Australian dawn ant. At this writing three years later, no further Martialis ants have been found. The Amazon is a very big place to look, however, and I expect a colony will eventually be located if the species is truly social, and perhaps by one or more of the growing group of young ant experts in Brazil.
    You may think of my story of ants as only a narrow slice of science, of interest chiefly to the researchers focused on it. You would be quite right. But it is nonetheless at a different level from an