Letters to a Young Scientist (13 page)
Discoveries like these, whether minor or important—and who is to say at first which it will be?—can be made only rarely without a thorough advance knowledge of the organisms studied. This precondition is sometimes called “a feel for the organism.”
Let me relate another story to reinforce this important principle. It occurred during an expedition I led in 2011 to the South Pacific. With me were Christian Rabeling, the ant expert and discoverer of the Amazonian “Martian” ant; Lloyd Davis, another ant expert and world-class birder; and Kathleen Horton, who was in charge of the complex logistics. We traveled during the austral spring of November and early December. Our destination was two archipelagoes, the independent island nation of Vanuatu and the nearby French possession of New Caledonia. In the process we visited localities where I had collected and studied ants in 1954 and 1955. I looked forward to observing changes in the environment that undoubtedly had occurred fifty-seven years later. I brought scanned images of my aging Kodachrome slides with me to make the comparisons exact. In particular I wanted to evaluate the condition of the wildlands and the reserves and national parks since 1955.
What original discoveries we made, in particular with the ants we planned to collect and study, would depend entirely on the knowledge we brought with us. We were in fact well prepared. We discovered many new species, and kept notes on the habitats in which they were found. But that was only part of the plan. We had bigger game in mind: to clarify, if we could, phenomena in the formation of species and their spread from one island group to another across the intervening ocean gaps. If you look at a map of the South Pacific and make Vanuatu your focus, you see how plants and animals that colonized this archipelago could have come from any of three bodies of land: Australia and New Caledonia to the west, the Solomon Islands to the north, Fiji to the east, or some combination of all three. Ant colonists, although completely landbound, might have made the journey by floating on the logs and branches of fallen trees or blown by storm winds. Queen ants capable of founding colonies might even have ridden in the feathers of far-ranging birds. We could not hope to determine how ants cross open water, but we did collect enough data to judge which island group contributed the most colonies to Vanuatu. It turned out, incidentally, to be the Solomon Islands.
This discovery was important enough to justify the hard work in the field, but we devised another question to ask and perhaps answer. Leaving aside the Solomon Islands, whose ant fauna was still poorly explored, we were aware of a huge difference between Vanuatu and the two archipelagoes on either side of it, Fiji and New Caledonia. Both are ancient, having existed with a substantial land area for tens of millions of years. Vanuatu has been in existence for a comparable period of time, but only as a set of small, shifting islands. Only during the last million years has its land area been more than a tenth of what it is today. The antiquity of Fiji and New Caledonia is immediately apparent in the richness of their faunas and floras. In particular, each is occupied by a large number of species, some highly evolved, that occur nowhere else in the world.
And what of relatively youthful Vanuatu? In November 2011 we were the first to take a close look at the ants on this archipelago. We knew that if it had a long geological history and large land area like New Caledonia and Fiji, we should expect to find a rich, highly evolved array of ants present. If, on the other hand, the current large area of Vanuatu had a relatively short history, as the geologists claimed, we should find a much sparser, distinctive array of ants there than occur on Fiji and New Caledonia. As it turned out, we found a smaller array, in accord with expectations from the record deduced by the geologists. But the ants of Vanuatu have not been inactive during their “brief” million-year tenure. We found clear evidence of new species in formation, and the beginning of the kind of expansion of biological diversity that is well advanced on the older archipelagoes. The ants of Vanuatu, to put the matter as succinctly as possible, are in the springtime of their evolution.
I have one more story to tell you from the South Pacific, because it is about a process unfolding there that may at first appear to be remote and exotic yet has global significance. It makes urgent the lesson of knowing where you are and what to look for when doing field research.
While on New Caledonia, our little team joined Hervé Jourdan, a seasoned resident entomologist of the local Institute of Research and Development. He led us on a trip to the Isle of Pines, a small island off the southern tip of the main island, Grand Terre, and, at least from the viewpoint of Americans, one of the remotest places in the world. Our goal was to learn what kinds of ants occur there, and to search for one species in particular, the bull ant
Myrmecia apicalis
. Bull ants are evolutionary cousins of the Australian dawn ant, and almost as primitive as that species in anatomy and behavior. Eighty-nine species of
Myrmecia
have been discovered in modern-day Australia. Only one,
Myrmecia apicalis
, is native elsewhere. The existence of this insect so far from the homeland raised questions of interest to biogeographers, whose business is to map and explain the distribution of plants and animals. When and how did the New Caledonian bull ant get to this remote archipelago? Which of the eighty-nine species back home in Australia are its closest relations? How has it adapted to the island environment? In which ways, if any, has it become special?
I wanted very much to answer these questions when I visited New Caledonia in 1955, but I could not find the species at all. The forest where it had been last seen on Grande Terre, the main island of the New Caledonian archipelago, had been cut over in 1940. In later years
Myrmecia apicalis
was considered extinct. But then Hervé Jourdan found several workers of the ant in a forested area on the Isle of Pines. We went there with him to locate colonies if possible and to learn all we could about this endangered species. To our relief we succeeded in finding three nests deep in undisturbed forest, and were able to film and study the ants day and night. The nests were located at the bases of small trees. Their hidden tunnels were capped with debris. Foraging workers, we found, leave the nest at dawn, climb singly into the canopy, return bearing caterpillars and other insect prey at dusk. Later we learned that
Myrmecia apicalis
is most closely related to a few Australian bull ant species with similar habits that live in the tropical forests of northeastern Australia. We still do not know how one such species was able to colonize New Caledonia, or how many thousands or millions of years ago it made the trip.
I’m telling you this faraway bit of natural history for a special reason. While on the Isle of Pines we confirmed the existence of a frightening threat to a large part of the island’s biodiversity, not just the New Caledonian bull ant, but a large part of the fauna. Another ant, accidentally introduced to New Caledonia in cargo in recent years, has reached the small offshore island of Isle of Pines and is taking over the forests there, destroying, as it spreads, the native ants, other insects, and in fact almost all of the ground-dwelling invertebrates.
The alien enemy is the “little fire ant” (technical name:
Wasmannia auropunctata
), which originated in the forests of South America. With humanity’s unintended help, the species is spreading throughout tropical regions of the world. I had first encountered this alien in the 1950s and 1960s in Puerto Rico and the Florida Keys. Since then it has reached and begun to expand in New Caledonia, where it is an especially destructive pest. Although its workers are tiny, the colonies are huge and aggressive. The species is as bad as the more famous imported fire ant (
Solenopsis invicta
), which has spread widely in warm temperate countries. The government of neighboring Vanuatu, aware of the dangers posed by the Wasmannia, is attempting to keep it at bay by spraying and exterminating beachhead populations whenever they are found on the islands.
The little fire ant is a particularly severe menace on the Isle of Pines. During our search for the bull ants and other entomological treasures, we visited several types of forests, including those composed of nearly pure stands of
Araucaria
, one of the signature plants of the New Caledonian archipelago. These towering steeple-shaped trees have prevailed on the fringes of the southern continents for tens of millions of years. We found that where the little fire ants had penetrated
Araucaria
groves, native ants and other invertebrates were almost entirely absent. The New Caledonian bull ants survived in a Wasmannia-free area, but that was only a mile or two from the slowly advancing fire ant wave. The final extinction of these unique insects, and very likely other native animals, might be only decades away.
Can the little fire ants be stopped? The French scientists at the Institute of Research for Development in Noumea have tried to find a way, but so far have met only failure. You may be thinking at this point that if Grande Terre and the Isle of Pines are so far away, why should we be concerned? I will answer with emphasis: because the little fire ants are only one of thousands of similar aliens spreading around the world. The number of invasive species of plants and animals, including disease-carrying mosquitoes and flies, home-destroying termites, pasture-choking weeds, and enemies of native faunas and floras, is increasing exponentially in every country. Invasive species are the second most important cause of extinctions of native species, exceeded only by the destruction of habitats through human activity.
To learn more of the details of the great invasive threat, and to find solutions before it has reached catastrophic levels, will require far more science and science-based technology than we now possess. Humanity needs more experts who have the passion and breadth of knowledge to know what to look for in the first place. That’s where you come in, and why I have told you this story of New Caledonia’s threatened bull ant.
A female of the fairyfly
Mymar taprobanicum
, a wasp parasite of insect eggs. The actual size is smaller than the first letter in this caption. © Klaus Bolte.
T
HERE IS ONLY
one way to understand the universe and all within it, however imperfectly, and that is through science. You are likely to respond, Not true, there are also the social sciences and humanities. I know that, of course, I’ve heard it a hundred times, and I’ve always listened carefully. But how different at their foundations are the natural sciences, social sciences, and humanities? The social sciences are converging generation by generation of scholars with biology, by sharing methods and ideas, and thereby conceding more and more to the realities of the ultimately biological nature of our species. Granted that many in the humanities, as if in a bunker, fiercely defend their isolation. Moral reasoning, aesthetics, and especially the creative arts are forged independently from the scientific world view. The stories of human relationships in history and the creative arts are potentially infinite, like music played upon only a few musical instruments. Yet however much the humanities enrich our lives, however definitively they defend what it means to be human, they also limit thought to that which is human, and in this one important sense they are trapped within a box. Why else is it so difficult even to imagine the possible nature and content of extraterrestrial intelligence?
Speculations about other kinds of mind are not pure fantasy. Rather, if informed they are thought experiments. Let’s try one. Imagine with me that termites had evolved a large enough size to have brains with a capacity equal to that of humans. That may sound entirely implausible to you. Insects have exoskeletons that encase their bodies like a knight’s armor. They cannot grow to be much larger than a mouse—and a human brain by itself is bigger than a mouse. But wait! Allow me a bit of flexibility in the scenario. In the Carboniferous Period on this planet, 360 to 300 million years ago, there were dragonflies cruising the air with three-foot wingspans, and four-foot-long millipedes pushing their way through the undergrowth of the coal forests. Many paleontologists believe that these monsters could exist because the atmosphere was much richer in oxygen than nowadays. That alone would allow better respiration and larger size in the chitin-encased invertebrates. Furthermore, it is easy to underestimate the capability of the insect brain. My favorite example is provided by the female of a fairyfly, one in a taxonomic group of extremely small parasitic wasps, which hatches from the egg of an underwater insect in which she has lived and grown up. She uses her legs as paddles to swim up to the surface. She digs through the tension of the surface film, and walks on top of it for a while. Then she flies in search of a mate, copulates, returns to the water, digs through the surface tension again, paddles to the bottom, searches until she finds an egg of the appropriate host insect, and lays one of her own inside it. The female fairyfly does all this with a brain almost invisible to the naked eye.
Equally impressive, honeybees and some species of ants can remember the location of up to five places where food is found and the time of day at each when food is available. Workers of an African hunting ant prowl singly over the forest far from their colony’s nest. They circle and zigzag during the excursion. As they travel, they memorize the pattern of the foliage seen above their heads against the sky. Occasionally, they stop and look up to summarize where they are: upon catching an insect, they use this mental map to run home in a straight line.
How can an insect process so much information with a brain not much larger than the period below the question mark at the end of this sentence? The principal reason is the way the insect brain—much more efficient by unit volume—is constructed. Glial cells, which support and protect the brain cells of larger animals, including us, are omitted in the insects, allowing more brain cells to be packed into the same space. Also, each insect brain cell has many more connections on average to other cells than do those of vertebrates, allowing added communication by means of fewer information distribution centers.
So if I have rendered to your satisfaction at least plausibly the existence in a past era of high insect intelligence, let me go on to outline the morality and aesthetics of an imaginary termite-like civilization on another planet similar to our own, which I’ve based on Earth termites of the present day but bigger and raised to human-level intelligence. It’s science fiction, of course, but unlike most such fiction, it is fully based on solid science.
SUPERTERMITE CIVILIZATION ON A DISTANT PLANET
Imagine, if you will, a vampire-like species that shuns the light of day, dying quickly if exposed to it. These termites come out to forage for food only if they must, and then only at night. They treasure complete darkness, high humidity, and constant heat. They eat rotting vegetable material. Some also consume fungi they grow in gardens mulched by rotting vegetation. As with some social insect species on Earth, only the king and queen are allowed to reproduce. The queen, her abdomen hugely swollen with ovaries, lies within the royal cell, doing almost nothing else but eat. She lays a constant stream of eggs, and occasionally mates with the little king who stands at her side. The hundreds or thousands of workers in the queendom, freed like human priests and nuns from sexual turmoil, devote their lives selflessly to rearing their brothers and sisters. A rare few of the young turn into virgin kings and queens, who leave the colony, find mates of their own, and start new colonies. The workers further attend to all of the other tasks, including education, science, and culture, of this supertermite civilization. Many of the inhabitants are soldiers, fitted with massive muscles and jaws and glands from which they spit poisonous saliva, ever ready for the chronic battles that break out among the colonies.
Life is spartan, and any deviation from the rules of the group, any attempt to reproduce or to attack others, is punished by death. Corpses of the workers that have died for any reason are eaten. Workers who grow ill or suffer injuries are also eaten. Communication is almost wholly by pheromones, from the tastes and scents of secretions released from glands located up and down the length of the body, as the source of our sound is in our larynx and mouth. Think of our human way in this remarkable line from Vladimir Nabakov’s famous novel
Lolita
: “Lo-lee-ta: the tip of the tongue taking a trip of three steps to tap, at three, on the teeth.” Imagine then the release of pheromones from the line of pheromones in different combinations, different sequences, perhaps a trip of three stages in puffs of pheromone from the openings of glands along the side of the body. Pheromonal music, translated into sounds, might sound beautiful to us. It could unfold in melodies, cadenzas, beats, crescendos, and, with orchestras of the supertermites participating, symphonies, much more. All this would be experienced by smell.
The supertermite culture would thus be radically different from ours, and extremely difficult to translate. The species would have its termitities as our species has its humanities. Yet—their science would be closely similar; its principles and mathematics could be mapped unambiguously onto our own. Supertermite technology might be more or less advanced, but it too would have evolved in parallel manner.
We would not like these supertermites, nor, I suspect, any other intelligent alien we encountered. And they would not like us. Each would find the other not just radically different in sense and brain, but morally repugnant. But this said, we could share our scientific knowledge to great mutual advantage. And, oh, before I forget to remind you. You don’t need to engage in fantasy to envision cultures, or whole faunas and floras, on another planet. In fact, my extraterrestrial termites, minus culture, are based on the real mound-building termites of Africa.
Similar wonders await your attention. The universal nature of scientific knowledge yet to be revealed includes a near-infinitude of surprises.