Like a Dream Full of Beetles

Transcription

1 MUSINGS Like a Dream Full of Beetles Marlin E. Rice..What sort of insects do where YOII come from?" )!Q1i rejoice in, Lewis Carroll, Through the Looking Glass I nthe brushy savanna of southern Africa, not far from lofty boulders of granite, stands a thorn tree. The trunk is slender, no bigger than a stout man's arm, and the upper branches stretch out in horizontal layers, flush with a contrast of delicate, fernlike leaves and small, vicious thorns that rival cat claws for sharpness. Most likely it is an ordinary tree, but this particular thorn tree stands large in my memory, for within my sight but beyond my reach in the prickly branches hangs one of the largest and most spectacular beetles on the African continent. But a beetle in the bush is only a dream, and dreams are fleeting unless captured. I am in Africa to teach at the University of Zimbabwe, but I have interests outside the classroom as well, and these are to explore the riches of the local insect fauna. The splendors of the insect world are legion, and the frontiers of discovery are infinite, but my greatest pleasure finds its origins with a specific family-the longhorned beetles. The Ministry of Agriculture maintains an insect collection in Harare and I stop to peruse the longhorned beetles. From a row of dark mahogany cabinets, one wooden insect drawer after another is gingerly pulled out with great expectations. I am not disap- pointed. Each drawer is packed with exquisite beetles of two kinds-beetles that accelerate the heartbeat with their wild colors, intriguing shapes, and exaggerated antennae; and beetles that create despair because I know I will never collect them all. So many beetles, so little time. My prejudice for the longhorned beetles quickly vanishes when a cursory inspection of other beetles in other cabinets reveals two captivating insects. The first is the Goliath beetle, Goliathus albosignatus Boheman, which out of five Goliathus species is the only one to occur in Zimbabwe and has been designated the rarest of the five by those who study such things. The second insect is the giant African tiger beetle, Mantichora scabra Klug. It is larger than any tiger beetle from North America, including the nocturnal and flightless Amblycheila cylindriformis (Say) I had seen on the high plains of western Kansas. Label data from both species are written down in hopes of deciphering how I might catch them myself. But the pursuit of these two marvels will have to wait, for it is May and they will not appear until the coming of the rains. The rainy season in Zimbabwe is still seven long months away. Winter advances slowly. The African bush is dry and only gets drier. The months are passed looking under rocks for ground beetles or beating the dwindling number of green trees for spiny-shaped leaf beetles. Under large rocks during the dry season, the ant-mimicking ground beetle Cyphloba graphipteroides Guerin was common, but the weevil Brachycerus sp. was collected only once. AMFRICAN ENTOMOLOGIST Volume 46, Number 2 Shortly after the middle of November the first rains come. A brilliant, billowy white thundercloud towers ominously over the land, bringing with it the promise of a torrential downpour that will soon saturate the ground. Winged termites spiral up from the pottery-red soil this evening, their flight signaling that the rainy season finally has arrived. A couple of nights later I grab my portable generator, mercury-vapor lamp, and white bed sheet and head north to the lush forest wedged in the river valley below MazoweDam. The light is set at a fork in a trail, deep inside the dense jungle. Dusk settles down thickly amongst the tall, gnarled trees as the first beetle is drawn to the light at the sheet, and within the hour a flurry of longhorned beetles is arriving faster than they can be snatched up. Alone in the African forest, with the suffocating darkness pushed back by the solitary light, my attention is completely immersed in the beetles that pepper the white sheet, that is, until a bushbaby, hiding somewhere in the blackness, gives out a chilling womanlike scream. The cry startles me-it sounds like someone being murdered-and thoughts of an early exit from the forest inundate my mind, but the attraction of the beetles is stronger than the temptation to retreat from creatures unseen in either the jungle or my imagination. Near midnight, the stream of beetles to the sheet slows to a trickle so I pack the The nocturnal ground beetle Anthia maxillosa F. carried impressive mandibles. 77

2 Animal dung was a favorite food for some beetles. A fresh pile of rhino dung attracted several species of scarabs; whereas the metallic green Onthophagus sp., with the backward-sweeping horns, was extracted from baboon dung. equipment and drive to Mazowe to inspect the lights at the only gas station in the village. Fluorescent lights are fascinating devices-they act like magnets, attracting not only beetles but also entomologists. And so it happens. At the station I cross paths with someone who is so out of place that he instantly is recognized as familiar because he is staring at bugs on the wall and holding an insect net. Bertie Gerschel, a native of France, has lived in Zimbabwe for 15 years, and he also is in pursuit of beetles. The ensuing conversation reveals a knowledge of the local beetle fauna, which impresses me because he knows where to collect the giant African tiger beetle. He notes the days following the first rains are an ideal time. We spread my topographical map across the car hood, and in the beam of a flashlight he marks the spot-with an X. We make plans to meet again, this time over dinner, I thank him, and then we part ways into the night. Late the next afternoon, I drive to the location of the X, park the car at the road's edge, and venture down a dirt path into the scrubby bush. A troop of baboons, barking their disapproval in my direction, bolts into the sanctuary of the surrounding boulders. The area looks perfect for hunting tiger beetles; the low vegetation was burned during the dry season and the ground is mostly bare except for small trees that have fallen and burnt and tufts of green bunchgrasses that have been the first to respond to the rains. I search through the fading light of a setting sun and shine a headlight into the African night. A giant, flightless tiger beetle would be easy to see, or so I thought, but only big, black darkling beetles scurry across the blackened earth. After two hours of diligent searching, I finally find a single giant African tiger beetle, but it is dead-flattened into the dirt by a tire. We are both crushed. Over dinner with Bertie several nights later, I lament my unsuccessful search for the tiger beetle. He is surprised at my failure, noting that he often has found them crawling across the road. I have not found it that easy. I also reiterate my desire to find the Goliath beetle. He thinks about my request for a long moment, takes another sip of his wine (French, of course), then leans forward and says in the hushed voice of someone revealing the secrets of a hidden treasure, "I'll take you to the spot if you promise not to tell anybody. It took me 10 years to find these beetles and I don't want to see 200 of your American friends here next year!" I make the promise. We drive far out into the bush. The sa- The metallic-wood boring beetle Sternocera orissa Buquet would perch on upper branches of thorn trees and was impossible to catch without the aid of an aerial net. The blister beetle Mylabris sp. was at times common on flowering morning glory vines. Leaf beetles, such as the brilliant pink tortoise beetle, Chiridopsis nigrosepta Fairmaire, the spiny-shaped hispine, and the black and yellow striped Diapromorpha sp., were beaten from leaves of woody vegetation. 78 vanna has been revived by the recent rains and the shrubs and trees are sprouting fresh green leaves. On a narrow tar road at an inauspicious location that looks no different from many others we have driven past, Bertie says, "Stop the car here, get out, and look in that tree." The trunk is slender, no bigger than a stout man's arm. It is an Acacia sieberana D.C.; a flat-topped thorn tree that could meld with any panorama of the African savanna. I walk slowly around the tree, my neck bent so far back it hurts, with my hand covering my eyes from the bright midday sun. High up in the horizontal branches are dark silhouettes-silhouettes of very large insects. I stand in amazement as Bertie takes measure of our good fortune; there are 8, 9, 10, maybe 11 Goliath beetles. The beetles are a ca talyst for an effervescence I cannot suppress and my hands tremble nervously as I screw together the sections of my tropical net. I fear that the beetles will suddenly awaken to the danger that circles below them and flee like the wind. Bertie graciously offers me the first attempt. My 8-foot vertical reach plus the 13 feet of net is barely adequate to reach the closest beetles. A mating pair of Goliaths hangs from the underside of a tangle of branches. The net is eased gently in amongst the layers of leaves but snags on a thorn. This slight disturbance of the branch triggers an immediate response, and I watch in disbelief at the agility and speed at which the beetles make their escape. It is reminiscent of AMERICAN ENTOMOLOGIST Slimmer 2000

3 hummingbirds in flight-quick, determined, and with a distinctive whir of small but powerful wings. I apologize to Bertie for having missed. "No problem," he says nonchalantly. "Try this one over here," as he points to another beetle on a different branch. The long handle is thrust almost straight up, but the angle reduces the effective width of the net to a very narrow couple of inches. The leading edge of the net taps the Goliath beetle, it tumbles downward, hits the trailing edge of the net, and ricochets off into a blue clear sky. Missed again! By the standards of baseball, I have struck out, but there are few rules in the quest for beetles. I am not defeated; at least not yet. We spot a second mating pair and Bertie suggests that I strike the underside of the branch with enough force to startle the beetles into dropping into the net. It almost works, but both beetles flutter out of the net before it can be unsnagged from the thorny branches. Five beetles, five misses-everything that could go wrong has. With more apologies mixed with a dose of frustration, I hand the net to Bertie and beg him to catch one of the beetles that has evaded my best efforts. I am not quite ready for what I see next. A unique and rather imperial twist is conceived to attack the beetles. Robson, Bertie's gardener, housekeeper, and all-around utility man has come along with us. He is about 6 feet tall and solidly built. With an order from Bertie, Robson squats down and Bertie As different as night and day, the giant African tiger beetle Mantichora sp. was rare but easy to catch because it was flightless. In contrast, the blue and yellow tiger beetle Chaetodera regalis Dejean was common on the white sandbars of the Save River but extremely wary and difficult to snare with a net. A.\tERICAN E~OMOLOGIST Collecting the large scarab beetles at sap flows on thorn trees required creativity and as much reach as possible. Some of the more spectacular beetles at these sap flows included the black and white Goliathus albosignatus (Boheman); the green, white, and red Dicronorrhina derbyana (Westwood); and Mecynorrhina passerinii (Westwood), which was dull, velvety black with apple-red spots. climbs up on his shoulders-the European, thrusting the 13-foot net like a lance while riding the back of the African. The scene best can be described as weird, but the piggyback maneuver does extend the net 5 feet higher into the tree canopy. It is exactly what is needed to catch the first Goliath beetle. In the bottom of the net, the beetle roars its wings in vain. It is a gorgeous male with a black, upturned, Y-shaped horn on a white head. Five thin white stripes reach back over a dark pronotum; and tiny, dirty white squiggles dance sideways across black e1ytra. It is a most incredible insect because it is big and bold and very much alive, which makes me realize that all the pictures I have ever seen in books are terribly deficient at portraying the character of this magnificent beast. As I stare in awe at the beetle that I hold firmly but delicately in my hand, the claws on the front legs reach forward, dig into my fingers, and pull with remarkable vigor to escape. Its strength surprises me, and two hands quickly are needed to assure its capture. Only after it is secure inside a bottle does my nervousness begin to calm. The Goliath beetle is now mine. Away from the road, and further into the bush, are more thorn trees. And more kinds of beetles. But the tall tree dilemma persists, Volume 46, Number 2 and Bertie has sent Robson off to bait for butterflies so we cannot foist our problem on him. Several large flying beetles lazily thread in and out of the canopy, safely above our reach, and unknowingly taunt our efforts to pull them out of the sky. In the face of desperation, collecting rare insects demands innovation. We decide to drive the car under a promising tree and stand on the roof. Bertie waves hand signals and offers directions as he stares up into the thorn tree, trying to triangulate where the car should be parked to give us the best angle on a beetle. I am more concerned that he does not overlook an animal burrow hidden in the grass that might swallow a car wheel. The mobile collecting platform is a success, and the thorn trees yield their beetle treasures to my net-each new species is a delight of form and colors. The catch of the day, based on Bertie's perception of rarity, is a handful of Cheirolasia burkei (Westwood). The beetles are amber brown with large, creamy yellow spots. The males have long and slender front legs with thick, feathery pubescence and a three-pronged horn on the head. It is a bizarre looking insect for a beetle and easily could grace the pages of a Dr. Seuss story. We also catch Dicronorrhina derbyana 79

4 lacks in glorious colors it more than exceeds in size. As tiger beetles go, it is a monster at 5.2 centimeters-i am holding the Godzilla of tiger beetles! One of the Goliath beetles and the giant African tiger beetle are kept alive for several days. I frequently find myself picking them up to contemplate the sequence of events that led to their capture, often not realizing that minute after minute is unconsciously drifting away while I stare at the magnificence of these insects. When an insect that is predictable and familiar to us in our own backyard is encountered in a more exotic environment, and is bigger or brighter or faster or more gaudy, it naturally strikes a note of wonder. Life is full of unforgettable events, and a special few are permanently and deeply etched in the memory as significant, such as marriage or the birth of a child. But when life is more narrowly viewed with a focus on the After the rainy season began, a mercury-vapor lamp attracted many beautiful species of longhorned beetles including a "creme-de-mint" colored Prosopocera lactator F., a ghost-white Prosopocera sp., a cryptically patterned Laziopesus sp. in which the male had densely pubescent protarsi, and Hoploderes sp. with a spiny black pronotum offset by two brilliant orange setal tuffs. (Westwood), a species in which the largest specimens are equal in size to the smallest Goliath beetle but more dazzling to the eye. The elytra are smooth emerald and margined with white, and the pronotum is either metallic green or red, depending on the angle at which it reflects light. This beetle produces a sweetly pungent pheromone, which clings to my hands like a fragrant mist. I breathe the odor deeply to help cement the strange and ephemeral experiences of the day in my mind. In contrast to the nocturnal long horned beetles, the flashy black and yellow Tragocephala sp. was day flying and easy to spot on the green leaves of its host tree. By midafternoon, all the thorn trees have been inspected thoroughly at least twice. We have 21 species of scarabs, including an elephant dung beetle the size of a golf ball, plus some longhorned beetles that are a bonus. Our persistence is rewarded with 12 Goliath beetles snagged from the thorny branches, and the newly formed depressions in the car roof are not too obvious unless you look at them from just the right angle. It would be hard to improve on the success of the day. "Don't move!" I yell at Bertie. He is under a thorn tree doing a two-step shuffle while looking up, trying to sight in on another Goliath beetle; but I am looking down and directly behind him, and within stepping distance darts a giant African tiger beetle. It scrambles into the grass, but it cannot fly, so its capture is imminent. The large serrated jaws bite into the air, reaching for anything that can affect its release, but my fingers safely pinch the sides of its body and hold it fast. It is the most mundane of colors-black with a tint of maroon-which is probably not the color most entomologists would envision when thinking of a tiger beetle. But what it 80 Other beetles attracted to the mecury-vapor light included the blue and yellow weevil, Polyclaeis sumptusoa Peringuey; a long, spidery-legged anthribid; and a pair of pleasing fungus beetles, Megalodacne grandis F. AMERICAN ENTOMOLOGIST Summer 2000

5 elusive, then, as an entomologist, capturing both the Goliath beetle and giant African tiger beetle eclipses all previous insect encounters and is a dream fulfilled. I am not alone in my appreciation of beetles; many others have had their imaginations sparked by the wonders of these creatures and their origins. One of the most quoted is the British philosopher J.B.S. Haldane, who supposedly stated that the Creator had "an inordinate fondness for beetles," and this thought recently was elevated to a title of a book that expounded the praises of these special insects that dominate our planet. The theologian Phillip Yancey wrote, "Surely it has theological significance that unearned gifts and unexpected pleasures bring the most joy." I would concur. Months after leaving Zimbabwe, I breathe deeply the distinctive and pleasant aroma that still saturates the brilliant green cuticle of D. derbyana. The smell awakens a sleeping memory and at the speed of thought I see myself standing beneath that ordinary thorn tree and looking up into the branches at all those spectacular beetles. If I were to never catch another insect, I could not complain. The experience of capturing beetles in the African bush would rank as one of life's unearned gifts and unexpected pleasures. It was like a dream full of beetles. Acknowledgment Thanks to Chris Chapano, National Herbarium, Harare, for the identification of the acacia. A very special thanks to Bertrand Gerschelj without his generosity and knowledge, there would have been no Goliath beetles and no story to tell. Many of the insects (except the longhorned beetles and large scarabs) in the photographs were identified with the gracious assistance of Chuck Bellamy, Transvaal Museum, South Africa; however, I assume responsibility for all identifications. My sabbatical leave was supported in part hy a J. William Fulbright Scholarship. Suggested Reading Evans, A. E., and C. S. Bellamy An inordinate fondness for beetles. Henry Holt and Company, New York. Holm, E., and E. Marais Fruit chafers of southern Africa (Scarabaeidae: Cetoniini). Sigma Press, Pretoria. Lachaume, G Les Coleopteres du monde lll-goliathini 1. Sciences Nat. Compiegne, Prance. ENTOMOLOGISTS Join a world-class system for total quality health care. As an Army Entomologist, you will be a vital member of the Army Health Care Team. You could have a variety of opportunities: conducting research, performing operational and consultative medical entomology, or consulting with staff at labs and preventive medical facilities. As an Entomologist in the Army Medical Service Corps, you will have the rank, respect and privileges afforded to Army officers. In addition, you will earn 30 days of paid leave annually, and benefit from housing and food allowances, no-cost or low-cost medical and dental care, post exchange and commissary privileges, and a generous retirement package. To find out more, or to have an Army Health Care Recruiter contact you, call: USA-ARMY Marlin E. Rice is a professor of entomology at Iowa State University. He has ventured to Africa twice; to Ghana in 1974 and to Zimbabwe in This is Journal Paper No from the Iowa Agricultural Experiment Station, Ames. ARMY MEDICAL SERVICE CORPS. BE ALL YOU CAN BE. AMERICAN ENTOMOLOGIST Voillme 46, Nllmber 2 81