Wings of the Rhinoceros
The big war in the Pacific was over, but Robert Owen’s war was just beginning. Unless it was brought under control, the incredibly hardy rhinoceros beetle threatened to destroy every coconut palm in Micronesia. After experiments with a strange array of allies—wasps, hedgehogs, fungi, click beetles, and undergrowth—an armed truce has been won. It could end any day.
Around 1942 the coconut beetle arrived in Palau, an archipelago in the Caroline Islands of the western Pacific. It probably came as a stowaway on a Japanese vessel from Malaya, Indonesia, or the Philippines. The Japanese colonial government was too preoccupied with its Pacific war to eradicate the beetle in the first months, while eradication was still a possibility. Then the war reached Palau itself. In the bombing and shelling, thousands of coconut palms were felled. Logs lay about on every island, making an ideal breeding ground, and the beetle population quickly exploded. Within ten years of introduction, the beetle had killed more than half of Palau’s coconut palms. Many of the trees that survived were injured and their copra production was sharply reduced. The damage in Palau was the worst in the world.
So the horned insect’s god was Mars, and war brought it to the Palau Islands. The insect in turn brought Robert Owen.
“From the first day, I knew it was the place I wanted to be.” Owen says. “Someone, I can’t remember who, took me all through the limestone islands in a small boat. They were so beautiful. So green and full of life.”
In winning the islands, the American military had inherited the beetle. Owen was one of the first officers in the new military government. A bomberpilot in North Africa during the war, he had left the Air Corps at war’s end and had worked briefly as port entomologist in Hoboken, then Seattle, before the chance came to work in the Pacific. He jumped at it, and moved with his wife to Guam. In 1949, on loan from the Department of Agriculture, he was conducting a general entomological survey for the Navy, which then administered the Trust Territory, when the Navy asked him to investigate the beetle on Palau.
In the genus Oryctes, of the tribe Oryctini, of the family Scarabaeidae, of the suborder Lamellicornia. of the order Coleoptera, there is a beetle named rhinoceros. Oryctes rhinoceros (Linn), as the beetle is known to the West, or Mengalius, “coconut-eater,” as known in Palau, begins life as a small, clear-white, fine-granulated, hard-shelled egg. The egg hatches into a larva. The larva in its first instar is very small, just a tenth of its eventual length and an even smaller fraction of its eventual weight. At this stage the larva is mostly alimentary canal, for its food is decaying wood, very low in nutrition, and the canal must pass a lot. By its second instar the larva’s epicranial suture has become more distinct. The left mandible has formed a tooth near the middle of its inner edge. In the third instar, the larva’s head darkens. The mandibles develop more complex molar areas. The dorsum begins to bristle.
Between instars the larva molts. As it rests in preparation for each molt, it becomes semi-translucent. Then its thorax swells, the old exoskeleton splits, a colorless fluid is released, and the larva struggles free. The larva is white when it first emerges. Within an hour its head and legs have turned pale pink, and within two hours a pale reddish brown.
The larvae of Oryctes rhinoceros are very strong. In research on diseases that might be used against the beetle on Palau, experimenters had trouble simply in infecting the larvae. “The grubs react violently to any disturbance and persistently try to bite the object that is in contact with their bodies,” wrote one researcher. The larvae could chew through hard boards and brass screening. They could give an entomologist a painful bite, if he was careless. “Oral intubation” was impossible without a total anesthetic, and the larvae did not anesthetize easily. Because they were log-dwellers, with very low oxygen requirements, half an hour of exposure to a carbon dioxide atmosphere was required to knock them out. They revived quickly on being handled and intubed. Researchers discovered that the best method was to pin down a larva with a patch of quarter-inch mesh, apply heavy pressure to keep the larva from squirming, and inject the disease agent through the mesh. The larva’s integument was so tough in the second and third instars that standard twenty-seven-gauge injection needles had to be honed before each experiment.
At the end of its third instar, the larva leaves its log and crawls down into the soil to pupate. The pupa is yellowish brown and rubbery. Most of the adult structures are visible, even the embryonic horn that will grow into the striking feature for which Oryctes rhinoceros has its name. It is possible at this stage to determine sex, for the male’s horn is longer in relation to its breadth than the female’s.
The pupa stridulates. By rotating its abdomen slightly, it causes a friction between abdominal segments and the noise results. The stridulation is fainter and slower than that of the adult male beetle, but more continuous. When the pupa is held in the hand, it buzzes, like a time bomb.
When the adult emerges from the ground it is a highly sclerotized black beetle with a hard exoskeleton, sharp spines on its tibiae, and powerful muscles in its legs and thorax. Its compound eyes are covered with a thick, transparent cuticle, through which the multiple facets beneath are discernible. Backward from the base of the horn flanges project, protecting the eyes. The head locks into a groove in the prosternum to keep it from wobbling from side to side when the mandibles are chiseling or when the horn is in use as a lever. The brain is small. The heart is seven-chambered. Metamorphosis has been total, and not even in its nervous and digestive systems does the adult resemble the larva.
It is hard to experience the strength of the adult beetle by handling it directly because of the spines on its legs, but by placing a book on the beetle’s back, bearing down, and trying to stop its movement across the floor, one gets a good idea. It is difficult to hold the beetle. It just scrapes along, like Atlas. It makes the human pressing down feel silly and a little scared.
The male sex organ, the aedeagus, is a large, heavily sclerotized, hooked structure that is entirely retracted within the body when the male is not copulating. In the average male, the aedeagus measures 10 mm. in length; the terminal hook, called the forceps, is a paired structure, smooth, blackish, and hard.
Oryctes rhinoceros, then, is a big, black, heavily hung, tough, pyknic, irritable beetle. A single adult can kill a palm tree.
The beetle prefers coconut palms, but where these are scarce it will live in other palms, and in pandanus, sugar cane, and pineapple. In coconut palms the beetle feeds in the crowns. It burrows into the soft heart of palm, where it feeds on juices from the chewed fibers and on the sweet sap that the injured heart sends up into the beetle tunnels. It is in this heart of palm that the tree’s embryonic fronds are furled. When a beetle has fed there, the new fronds pushing up from the crown are bilaterally notched, like the snowflakes that children cut in folded paper.
Deep within the heart—in the palm’s heart of hearts—there is a growing point about the size of an apple, and though it is not likely that this apple tastes better than the rest of the heart, the beetle’s mandibles sometimes take him through it. The tree then dies, for palms, unlike most other trees, have no alternate growing points.
The death of the palm does not end its trials. When the frondless pole of a dead tree has decayed sufficiently, female rhinoceros beetles lay their eggs in the bark of the upper portion. The eggs hatch, and the larvae eat their way downward. The bark remains intact, but after a time encloses nothing but sawdust, larva feces, and larvae. One day the stump blows over in the wind. Cushioned by the sawdust, few larvae are hurt. They resume eating as if nothing had happened. They grow through their remaining instars, then burrow into the soil to pupate. The beetle has, man and boy, erased an entire tree.
The reproductive potential of the beetle is crushing. Dr. Linly Gressit. a student of Oryctes, estimates that the average female lays ninety eggs in her lifetime. With an average life cycle of one month, and assuming a one-to-one sex ratio, she gives rise to a theoretical 186,390 progeny at the end of the first year, each of which offspring could kill a coconut palm.
Insects are notorious, of course, for this capacity on paper to multiply. But in an insect’s native land, predators and other mitigating forces have also evolved to keep such numbers only theoretical. The origin of the genus Oryctes is Africa, and the homeland of the species rhinoceros is Southeast Asia, in both of which may be found numerous Oryctes predators of all phyla, shapes, and sizes. But in small oceanic islands with the simple ecosystems characteristic of Oceania, places where the genus is unknown, there are no such marshals and deputies waiting to greet the beetle.
When Robert Owen came to Palau in 1949. he surveyed the damage and wrote a strong report. The control program begun in 1947 was a failure, he said. Its bounty system, a dollar paid for each dead palm cut down, was ill conceived. There was no follow-up to assure that the bounty trees were destroyed after they were felled, a failure that could well leave the beetle with more breeding material than before. Nor was there any guarantee that the bounty trees had been dead. “Certainly,” wrote Owen, “the prospect of immediately making a dollar by cutting down a tree must frequently have seemed more expedient to the natives than waiting for the tree to produce a dollar’s worth of copra.” There was no evidence that Scolia ruficornis, the wasp introduced to Palau as a biological control, had become established. Neither was there any certainty that, once established, the wasp would be effective. “Unless an effective sanitary program is pursued or a successful biological control is found,”Owen concluded, “the Rhinoceros Beetle will inflict increasing damage on the coconut trees of the Palau Islands and will eventually spread to Guam and other island groups in the Trust Territory.”
This prophecy shook the Navy. The prospect of increased damage in Palau was bad enough, but the Palaus are high islands, not dependent on coconuts alone. In the greater part of Micronesia, in the groups of low atolls, such as the Marshalls, where the coconut is the only source of cash and in certain seasons the only source of drinking water (as Owen was careful to point out), the palm is the very tree of life. The beetle’s arrival there would be genocidal. The Navy asked the Department of Agriculture to look for someone to run a revitalized control program. Agriculture picked Robert Owen. And Owen himself, when asked twenty-three years later whether he had had anyone special in mind in pushing for the program, answered, “I had me in mind.”
The effort to control the rhinoceros beetle was forty years old in the Pacific when Owen joined it. In September, 1909, the beetle had been first observed in Western Samoa. A strict quarantine by the governments of surrounding islands confined it there for many years. Shortly after its Samoan appearance. a biologist named Friederichs began a search of the Eastern tropics for a biological control. He found only a green muscardine fungus, which he introduced to Samoa. The fungus had no effect, so Friederichs introduced the European hedgehog and vole. These were the first of many animals to be pressed into service against the beetle. The hedgehog and vole, blinking in the Samoan sunshine, were released under the palms. They disappeared into the tropical vegetation, never to be seen again. Accounts of their introduction say simply that they did not survive. They deserve more sympathy. The two rodents were Kipling characters, soldiers who perished in an alien land. They fell on strange soil, without knowing why.
Friederichs next suggested the introduction of two wasps, Scolia oryctophaga and Scolia carnifax. S. oryctophaga had the right name for the job, certainly. It would eventually take its turn against the beetle, though Friederichs was never able to arrange the introduction himself.
In 1924, the beetle appeared on Wallis Island, four hundred miles north of the British colony of Fiji.
In the 1930s, a British entomologist named Simmonds. then a middle-aged man who had spent much of his career in the Pacific, explored the tropics intermittently for a good beetle parasite. In 1935 he searched Malaya without finding anything. In 1939 he traveled to Java, Mauritius, Madagascar, and Zanzibar. He discovered no parasites specific to Oryctes rhinoceros, but found that other species of the genus Oryctes were held in close check by a number of predators. He set about finding a predator that would work in Samoa. First he shipped a large number of Scolia oryctophaga from Madagascar to Samoa, but the “Orycteseater” failed to establish itself. Simmonds guessed that the reason was the absence of a cool season in Samoa. He turned elsewhere. Correspondence with the Zanzibar Museum revealed that Scolia carnifax was an efficient Oryctes predator. He tested carnifax in Mauritius, but was unable to get the wasp interested in the Oryctes grubs in his laboratory. When he reached Zanzibar, he discovered that the Museum’s carnifax specimen was mislabeled. It was not carnifax, but Scolia ruficornis. He tested this wasp, and it proved to be the real predator.
Scolia ruficornis is a big, blue-black wasp with ice-blue wings. Its hind pair of legs are hairy and remarkably long and muscular. It has an abdomen like a bomb, swelling full and ominous, then narrowing sharply to its fatal point. Simmonds considered this wasp promising in that the Zanzibar climate was much like Samoa’s, and the wasp would feel at home. But it was a gamble, because it was not a true parasite of the coconut rhinoceros beetle, only of the beetle’s cousins. Simmonds released the wasp in Samoa, and it established itself. The fact of establishment meant that ruficornis had made the adjustment to the new species of beetle, for there was nothing else in Samoa for the female wasp to parasitize when she laid her eggs. In time ruficornis seemed to have some effect in controlling the beetle population.
There had been no other developments in beetle science at the time Owen began his control work in Palau. Friederichs’ search for a solution had begun before Owen’s birth, yet in the years following the beetle’s 1909 debut, Palau was only the third place in Oceania it had reached, and the danger to the entire Pacific area was considered only a potential one. There were few workers and little money available for beetle research,
Owen started by organizing a sanitation program. Sanitation was then the only effective method of controlling Oryctes, and it remains the basic method today. It is costly, hard, unending work. Dead stumps are cut down and hauled to the sea. Vegetable refuse is buried or scattered. By force of human labor, the female beetle is denied a place to lay her eggs.
From the beginning, Owen’s campaign against the beetle was a curiously moderated one. “I didn’t want to use chain saws and tractors,” he says, “because once the people in the villages saw it done that way. they wouldn’t want to go back to the simple ways.”
It was Owen’s professional judgment that the beetle could never be eradicated in Palau; it could only be kept under control. This meant that for the rest of time, or at least until the islands were reclaimed by the sea, Palauans would have to coexist with the beetle. The United States had promised to return the territory it held in trust to the Palauans, its owners, and when that day came, Owen did not want Palauans dependent on a foreign technology.
In one of his first quarterly reports Owen wrote that, according to the Chief of Melekeiok, the beetle was breeding in the nesting mounds of incubator birds. Owen began a brief history of the incubator bird, or megapode. describing how it uses its big feet to kick up mounds of soil and fallen vegetation, then lays its eggs within, to be incubated by the heat of the composting material. The megapode’s life history becomes a very long aside in Owen’s report, and reads almost as if he did not realize where his thoughts had taken him. It may have raised some eyebrows at headquarters.
The Chief of Melekeiok’s story was likely true, Owen concluded. “If so, it raises a rather delicate problem. The incubator bird is a rare and unique native bird well deserving protection. On the other hand, if it provides sufficient breeding material for Oryctes rhinoceros . . .?”
In 1952 the beetle appeared on Vav’u, in Tonga, and in 1953 it reached Fiji. The beetle was now becoming everyone’s problem, and Owen wanted a Pacific-wide campaign against it. As a member of the Invertebrate Consultant Committee for the Pacific (ICCP), a committee of the Pacific Science Board of the National Research Council, Owen pushed for international cooperation. The ICCP approached the South Pacific Commission (SPC), an international organization based in New Caledonia, and asked that the SPC become coordinating agency for the various groups fighting the beetle. The SPC had been hearing similar sentiments from other parts of the Pacific and it agreed to play a coordinating role.
In 1953 the SPC stated that eradication was not a possibility. Workers would have to be satisfied by simply controlling the beetle’s numbers. Sanitation was the only sure method of control, but it was costly. Insecticides would not work, for at no time in its life cycle was the beetle sufficiently exposed. As a larva it fed within logs, as a pupa it reposed beneath the soil, and as an adult it fed deep in the palm heart. Palm crowns could be individually treated with a benzene hydrochloride mixture which had some success in repelling the adult beetle, but this required a large labor force and more money than the copra economies of the Pacific could afford. All these things pointed to a biological control -a predator or disease that would effectively limit beetle populations. The SPC announced its intention to spend its energies in the search for such a control.
In the 3 million square miles and the thousands of islands of the U.S. Trust Territory, there were only two entomologists. Netherlands New Guinea didn’t have one, and other Pacific territories were similarly lacking. As its first act, the SPC hired an Indian entomologist, T. V. Venkatraman, and sent him searching for beetle parasites and predators. It commissioned another entomologist, a resident of Western Samoa, to study the range of the beetle, and hired a chemist who began testing palm extracts in a Queensland laboratory in an effort to find a beetle attractant. The budget for the first year was £10,000.
The SPC formed a Technical Advisory Committee on the Rhinoceros Beetle. Committee members were government entomologists from the French Institute of Oceania, in New Caledonia; the Department of Agriculture, Fiji; the Division of Agriculture, Hollandia, Netherlands New Guinea; the (Australian) Territory of New Guinea; the Department of Agriculture, Pago Pago, American Samoa; the Entomological Research Station, Nelson, New Zealand; and the Staff’ Entomologist for the Trust Territory of the Pacific Islands, Robert Owen.
In May, 1954, the roving entomologist, Venkatraman. made his first quarterly report from southern India. He had discovered that beetle larvae lived in cattle manure heaps. They fed gregariously along the edges of manure pits, usually about six to ten inches beneath the surface. He noted that when manure was stored in concrete pits that also drained cattle urine, no larvae were found. Perhaps that was a clue. Then he began a list of possible predators, a list that in the next years would become very long. He reported that fowls, crows, ducks, jackals, dogs, squirrels, held rats, and bandicoots all had been observed to dig out the grubs and eat them.
In August, Venkatraman reported from the coastal groves of coconut palms between Cape Comorin and the Malabar border. He had discovered his first promising predator. It was from the family Elateridae, which includes the click beetles and fire beetles of the tropics. His prospect was “a large, shiny reddish-brown elaterid larva with prominent dark head and well developed mandibles.” This elaterid larva had the right kind of face, certainly. “As soon as it comes in contact with an Oryctes grub,” wrote Venkatraman, “it gets hold of it by means of its powerful mandibles and pierces the body and feeds on the body fluid through the punctures made invariably on the thoracic segments.” It sounded like a hell of a larva.
Venkatraman reported that in the laboratory one of his elaterids had consumed eighty Oryctes grubs. This specimen might have been just a gym fighter, of course, but eighty wins and no losses was an impressive record, even when compiled under the gaze of a friendly scientist. The elaterid had a single character fault: in laboratory conditions it was cannibalistic.
Yet as Robert Owen read about the elaterid, sitting at his desk in Palau, he failed to become excited. He knew that reproduction in the family Elateridae was too slow. He never entertained the smallest hope that an elaterid would be the answer.
Venkatraman reported several other possibilities. There was a mole cricket, unfortunately also a cannibal. There was a fly, Sarcophaga fuscicanda, but it was too flexible in its preference for victims. Venkatraman recommended forgetting about it. There were several bacterial diseases. The trouble with these was that they had to be injected in individual larvae. Spraying the disease agent on the beetle’s breeding media did not work.
In February, 1955, Venkatraman reported from Ceylon. He had high hopes for the place, for like the Pacific islands it had very little seasonal variation in temperature. He wrote that in the wet zone of Ceylon, coconut logs were the beetle’s favorite breeding place, though it also used cattle dung and elephant droppings. Then he noted, “Although little attention is paid to coconut cultivation in Ceylon, the palm grows luxuriantly in the important coconut districts, producing high yields. The rhinoceros beetle is present throughout the island but the incidence of the beetle in general was low in the major coconut area.” This plenitude of coconut and absence of beetles occurred “in places where the palms are overcrowded with thick undergrowth of weeds and creepers.”
In these observations there was a hint at what later would become an effective method of beetle control. But if Venkatraman saw it and played with the idea, he soon discarded it. He was intent on finding a parasite. Owen read Venkatraman’s latest observations with interest, for he himself had observed the effects of dense undergrowth on beetles, and he was thinking of a way to put them to use.
Venkatraman continued. He attributed the low incidence of Oryctes in the wet zone of Ceylon to the predations of his elaterid beetle, to the competition of termites for logs, and to the presence among the Ceylonese palms of giant monitor lizards. In the very wet zone—the coastal belt near Galle and Tangalla—the monitor lizard appeared to be the principal predator. Monitor lizards were abundant in the coconut palm estates because the human inhabitants were Buddhists. Buddhists do not kill lizards, so wherever there were Buddhists there were monitors. It was common to see a dozen monitors working a Buddhist coconut garden at one time. They clawed into fallen togs and climbed dead standing trees, searching for grubs. They received some help. Venkatraman added, from the ruddy mongoose.
Owen considered all these possibilities. In Palau he had no ruddy mongooses, but he did have monitor lizards. And though he had no Buddhists, the Palauan people did not go out of their way to kill lizards. A Palauan monitor killed a chicken now and then, or stole an egg, but the people had no great animosity toward it. They might as well have been Buddhists.
Unfortunately, that made little difference, because of the West Indian toad.
The Japanese had introduced the monitor lizard to Palau to control rats, but had then imported, without much foresight, the toad. Toads are easier for a monitor to catch than rats, so the monitors turned to the toads. Unfortunately for the lizard, there are adrenalin glands in the toad’s head. A monitor lizard that mouths a toad goes on a trip, for adrenalin is Mother Nature’s methadrine. A number of monitors had overdosed on toad, and the lizard population was on the decline. In Palau, monitor lizards would not be the answer.
Venkatraman next reported from Burma. His stay there would be cut short, he said, because “the internal conditions of that country are unfavorable,” but his list of creatures known to kill the rhinoceros beetle had grown. Among the many were a black carabid beetle, a blue beetle, a reduviid bug from Mysore, various mites, a centipede, and a tree lizard from Malabar, a lizard from Mysore, and certain Burmese bats and toads. Venkatraman predicted that somewhere in India, Ceylon, Burma, Siam, Malaya, Indochina, southern China. Hong Kong, or Formosa; in the Hainan Islands, the Ryukus, the Philippines, or the Indonesian Celebes; in Ceram or Amboina. the right predator was waiting to be discovered.
From time to time in the long campaign against the beetle, rumors of a new bug would come to Palau. A scientist searching a foreign field would stumble upon what looked like the bug. He would describe its laboratory record against the beetle. In subsequent reports he would tout his insect. There were many such bugs, the White Hopes of the entomology game.
The White Hope with the most advocates was probably Platymerus rhadamanthus, a large red and black assassin bug. The assassin bug had a pleasantly oryctophagous look. Its biting mouthparts were wickedly curved. It did not resemble the praying mantis exactly, but it had the mantis animus, the intelligent and lethal head. In the fourth and fifth instars, assassin nymphs attacked and killed beetle larvae; but better than that, the adult assassin bugs killed adult beetles in palm crowns. It was the first predator known to do so. The assassin tipped the beetle on its side, held its prey still with two front legs, and inserted its stylet into the gular region, or between the abdomen and thorax, or ventrally where the head joins the prothorax. In one palm crown under observation by scientists. an assassin bug seized a beetle, slipped its stylet in neatly, “and afterward left the carcass of the beetle hanging by a leg which had become entangled in the fibres.” It was a good, sordid death for Oryctes rhinoceros.
Where there was water the assassin bug drank readily, and the frequency of its kills increased. The females were the killers. Occasionally a male would try in a bumbling way to attack a beetle, but he usually failed to dispatch it. One laboratory female assassinated a beetle while she copulated, and afterward she and her mate ate her victim. Platymerus rhadamanthus was that kind of girl.
The assassin bug was shipped in all stages of metamorphosis to Fiji. New Guinea. New Caledonia, and Palau. Over a period of several years Owen released thousands of them, usually ten to each palm crown. He was never able to recover any. It was a mystery. The assassin was one of the few predators that Owen had much hope for. They were so easy to raise in the laboratory. There were no disease problems. But they did not take hold in Palau, or anywhere else in the Pacific.
There were other White Hopes vith promising names, like Neochryopus savagei, a hardy bug that survived shipment well, and others, like Scarites dubiosus, with more doubtful names but good reputations. (S. dubiosus was from Assam, a jet black, voracious feeder that bit first or second instar beetle larvae in the head, briskly sucked the contents, and in forty minutes drained the grub dry.) Yet in each of these insects there was a flaw.
Because Africa was the center of dispersion for the genus Oryctes. many workers directed their hopes to that continent. An entomologist named Hoyt went searching there. In Sierra Leone, he seeded several oil-palm logs with Oryctes larvae and waited to see what would happen. One log was soon entered by a small, grayish rat, which ate several grubs and departed. For two weeks nothing else happened. Then one day all the logs were entered by swarms of driver ants, and all the larvae were eaten. The ants entered through old holes made by xylocopid bees. They ate everything but the head capsules of the larvae. As the entomologists of various Pacific territories read Hoyt’s report of this, they imagined, for a moment at least, armies of driver ants marching over their islands. They quickly dismissed the idea, as Hoyt himself dismissed it. “Because of the driver ant’s habits,” wrote Hoyt, “such an introduction would not be popular with the inhabitants, to say the least.”
One autumn an entomologist named Fred Bianchi left Belem, Brazil, and journeyed eight hundred miles up the Amazon to Manaus. He was looking for predators on the subfamily Dynastinae, which comprises a number of beetle genera in the family Scarabaeidae, of which Oryctes rhinoceros is also a member. He hoped to find a predator on Dynastinae that could acquire a taste for rhinoceros. the distant cousin of its traditional. South American victims. (The dynastid beetles are themselves horned and are also called rhinoceros beetles. To avoid confusion, the Pacific beetle is properly called the coconut or Indian rhinoceros beetle.) In South America, where Bianchi now searched, there is a dynastid named the Hercules beetle, it is nearly the largest insect in the world. Males of the species grow more than five inches long, and have two horns. The predator that could slay this insect Hercules would be promising indeed. Natural law required that some Brazilian creature had devised a way to do it, and Bianchi hoped to find that creature.
Fifteen to twenty dynastid species were said to live in the area, but Bianchi failed to find a single beetle. Brazil was poor country for beetles, he reported, because of the competition for breeding logs from “termites and ants, which crowd the regions to a degree not imaginable by anyone who has not been there.” But Bianchi did glimpse one tantalizing possibility.
“I saw on one occasion a very large black scolid wasp.” he wrote, “which from its size I judged to be a parasite of some dynastid.” Bianchi chased the wasp, but was unable to catch it.
He reported his glimpse of the wasp from Panama. where his search for a predator took him next. He wrote by the fitful light of a kerosene lantern, in pencil, in a student’s exercise book. The South Pacific Commission received his report, typed and mimeographed it, and sent it out. it arrived at desks in Melanesia and Micronesia, where entomologists glimpsed the wasp in their imaginations. Who was the mystery wasp? What species? Had it been the answer? Entomologists throughout the Pacific wondered.
Of all the insect contenders, only Scolia ruficornis, the wasp introduced to Samoa by H. W. Simmonds decades before, was at all effective in the Pacific. One by one, the other bugs failed. The coconut beetle was still champion. Outside the class Insecta, the list of possible predators continued to grow, but to no avail. Added were the Zanzibar pouched rat. the Zanzibar lemur, scolopendrid centipedes, tree shrews, flying lemurs. In Africa Hoyt discovered a nematode that was transmitted between beetles during copulation and he tested it. (The entomologists would have stopped at nothing to win.) Unfortunately, it proved impossible to culture the nematodes; the venereal infection had no dramatic effect on the beetle, anyway.
In his own research, Owen developed a way to harvest and ship cocoons of Scolia ruficornis. Before this the wasp had been shipped as an adult, with very high mortality. Owen’s cocoons were tough, easily shipped over long distances and long periods of time. This success might have made him an advocate of the scolid wasp, but it did not. He was careful in his claims for the wasp. He reported simply that in Palau, as in Samoa, the wasp seemed to have some effect in controlling the beetle.
He was similarly cautious in his claims for vegetative barriers.
The idea of vegetative barriers was Owen’s own. It was a simple idea, but it did not jump fullblown into his head. He had walked under palm trees for eight years before it became perfectly clear. In his wanderings Owen noticed that beetles were sometimes deflected by a single leaf or twig. “Have you ever seen one of those things fly?” he asks today. “He lifts those armor-plated wing covers, revs up his wings, gets them buzzing, and then staggers off. If he hits a leaf or anything, he folds up and falls to the ground. He has to start again.”
Getting airborne again was hard for the beetle. It was seldom able to take off directly from the ground. It had to climb partway up a trunk and then drop off, like a pterodactyl from its cliff. If it encountered an obstacle more than a few times it became exhausted. Owen assumed that this was why beetle damage seemed to be diminished in poorly managed palm plantations where vines and other vegetation grew uninhibited. On a trip to Samoa, Owen had visited both “European-style” plantations, kept neat and parklike by grazing cattle, and “Samoan-style” plantations, which were very badly managed, according to conventional theory, and he had been struck by how much less the jungley Samoan plantations suffered from the beetle. Apparently the beetles were intercepted before they reached the Samoan palm crowns. Owen began to wonder about deliberately planting such barrier vegetation as a cultural method of beetle control. Would a continuous canopy of trees, a secondary canopy beneath the palm crowns, stop the beetle?
Owen’s perceptions were an ecologist’s. If he had been intent on something less than the whole environment of the beetle, it is doubtful that the barrier idea would have occurred to him. (“When I came to Micronesia I learned the plants before the insects,” he says. “What would be the use of the other way?”) He was not watching simply as an entomologist when he saw deflected beetles fold their wings and drop to the ground. For forty years entomologists had seen that, but none had thought to put the observation to use; or if the barrier idea had occurred to them, it did not hold the appeal it held for the man whose heroes were Audubon and Muir. For someone convinced of nature’s rightness, the barrier theory was wonderfully gratifying. It rewarded all the principles of the ecologist’s faith. If the theory proved true, it meant that palm forests left to themselves were better off. It meant that in diversity is stability. If the forest was allowed to retain some of its original complexity, that complexity would serve as a reservoir of potential from which a new arrival such as the rhinoceros beetle, as alien to the place as a creature from another planet, could be held in balance. It meant that the conventional wisdom on coconut palms—that plantations should be monocultures kept carefully bushed and neat—was wrong. What the copra experts were learning in agriculture school was good only in an ideal world where no beetles flew. The real world was uglier than that. There was a horned insect loose in it that cut the hearts from living palms. By simplifying the ecosystem, the monoculturalists were preparing a table for the beetle. They were clearing lofty galleries through which the beetle could sail unimpeded.
Earlier in the beetle campaign, a number of workers had become concerned that the mystique of biological control was diverting too much energy from other possibilities, such as light traps and chemical attractants. They were afraid that the idea of finding an insect ally to defeat an insect enemy was too pleasing in a poetic way. But that mystique had nothing on the potential mystique of Owen’s barrier idea. A barrier solution did not require any searching of foreign lands. The answer lay right at hand, in natural processes that needed only to be recognized. It was cheaper. If the barrier was natural and the plantation was just left to itself, it would save the entire cost of cultivation. If the barrier was an artificial canopy, of leguminous trees, say, planted to fix nitrogen in soil that the coconut palms deplete of nitrogen, then maintenance would still be less expensive than keeping the plantation bushed.
But Owen kept calm. He set about devising ways to test the idea, and to find which kind of barriers would be most effective. The barrier idea was his own minor Origin of Species. He might have been forgiven for pushing it. but he kept it to himself until he was sure.
The beetle war has had no satisfactory climax. By 1962 the insect was under control in Palau, but Owen could not be certain to what extent his own efforts were responsible. This was a problem for all beetle fighters. Owen’s scolid wasps had spread, undeniably. Their cocoons were being recovered from all parts of Palau. But there was no way to prove that their impact had been substantial. Owen’s vegetative barriers seemed to have an effect, and he succeeded in making it a Trust Territory requirement that all homesteaders include barriers in their seedling plantations, but he could not prove the effectiveness of the barriers in an incontestible way. He was not even sure how they worked. It was possible that their effect was to block the beetle’s sensory perception of the palm crowns rather than block the beetle physically, though Owen didn’t think so. And it might have been the Palauan ecosystem that had made the real adjustment to the beetle. It takes time for native predators to learn that an exotic arrival is good to eat. A delayed reaction by the environment. in the discovery by monitor lizards, rats, and pigs that beetle larvae tasted good, was surely in part responsible for the decrease in beetle damage. How much was due to Owen and how much to ecosystem was hard to say. It was impossible for one entomologist with a dozen helpers to gauge the forces at play in 188 square miles of island jungle.
In Owen’s barrier experiments, both a neglected plot where native vegetation was allowed to spring up among the palms, and a second plot where leguminous trees were planted as a barrier, suffered less beetle damage than a third plot kept conventionally bushed, but the difference was not spectacular. It was difficult to design experimental plots that would produce proof, and Owen was not particularly eager for such proof, anyway. He is not a man anxious for recognition. He himself knew that the barriers helped against the beetle, and that was enough for him. He was not driven to demonstrate it to the world. After the South Pacific Commission held its first beetle conference in Fiji in 1959. Owen’s personal war with the beetle ran downhill.
The United Nations entered the beetle wars in 1961, and immediately appropriated sums of money that made the SPC’s original one-year grant of £10,000 look very small. It was wonderful what a little money did; scientists who had resigned themselves to years of impasse now felt the flush of it. Some of them began talking of eradication again.
Much promising work on chemical attractants and chemosterilants has followed the entry of the United Nations. The new research has turned up a virus disease that, in Owen’s opinion, is the best biological control to date. Sanitation remains the basic method of control, however. The victory over the beetle remains in doubt. The beetle waits in the wings for typhoons as potent as Opal and Louise, which in 1964 killed thousands of Palauan palms, providing breeding logs for countless larvae and forcing Owen to start from scratch. The beetle waits for another war.
Owen’s history and the beetle’s are intertwined. Their last ten years together have been a standoff, but it will not necessarily always be so, and today in Owen’s office insect boxes full of pinned beetles still decorate the walls like wanted posters in a post office. Owen believes that quarantine is only a holding action. Sooner or later the rhinoceros beetle will spread to other islands of the Trust Territory. The longer that is delayed, the more time entomologists will have to improve control methods; but Owen knows that someday, sorting his mail, he will come upon an urgent cablegram and open it to read that the beetle has appeared in Truk or the Marshalls.
Owen and the rhinoceros beetle have lived a curious symbiosis. It would seem that in Owen’s view of his own life, the beetle should figure as horned nemesis, or at very least as fond enemy. It did seem so, at any rate, to a friend who sat and drank with Owen recently, watching the evening light on the limestone islands beneath Owen’s bungalow. The friend asked Owen if he ever felt sentimental about the beetle; did he ever say to himself that, but for this small insect, he would still be in Hoboken? It was the kind of question that Owen finds foolish. No, Owen said, he never felt sentimental.
The friend thought he had asked a good question, and he persisted. What would Owen have done, then, back in 1949, if the beetle had not been in Palau for him to fight?
“I would have written a different report,”Owen said. He smiled a devious smile. “There are lots of insect pests in Palau, you know, I would have found another insect.”□