A Class of Distinction -- page 3
There is no question that insects have shaped and molded human civilizations.
On more than one occasion, the presence of insects has thwarted human attempts
to colonize new settlements. Early Norse communities on the island of Greenland,
for example, were abandoned long before Columbus "discovered" the New World
because the settlers could not compete with insect herbivores (probably
armyworms, Agrotis noctua) that pillaged their crops and pasturelands.
Mosquitoes and chiggers (the immature stages of certain mites) foiled Francisco
de Montejo's attempts to conquer the Mayan civilization in 1549 and delayed
Spanish rule over the Yucatan peninsula (Mexico) by nearly 150 years. Even
today, tsetse flies (Glossina spp.) prevent colonization of large
parts of central Africa because they spread the trypanosome parasites that
cause sleeping sickness in humans and nagana in cattle.
On the other hand, insects have also served to accelerate cultural evolution. Silkworms, for example, were certainly a driving force behind the establishment of trade between Europe and China, and were still
The sociological impact of insects has been keenly felt on the battlefield. It is certainly no exaggeration to say that, over the course of human history, more soldiers have died from lice and mosquitoes than from bullets and bombs. These insects spread diseases that have affected entire armies, influenced the outcome of wars, and determined the fate of empires.
The wartime impact of insect-borne disease has decreased ever since the discovery of modern chemical insecticides. The turning point came during World War II (1942-1945) when American forces gained a tactical advantage over their enemies by using DDT, a newly discovered insecticide, to kill the lice and mosquitoes that spread disease. In fact, DDT has been credited with saving more lives than penicillin, particularly in the Pacific theater. The Japanese army was not well-equipped to fight insect-borne disease, and some historians believe that widespread epidemics of typhus and malaria would have soon forced Japan to surrender, even if the United States had not dropped the atomic bomb.
Culture, Religion, and Aesthetics
In view of their abundance and the range of their impact on the lives of our early ancestors, it is not surprising that insects have become thoroughly integrated into human culture from arts and crafts to mythology and religion. In ancient Egypt, for example, people saw how the scarab beetle (Scarabaeus sacer) rolled a ball of manure along the ground and concluded that a giant celestial dung beetle must roll the sun across the sky each day. Thus, the beetle became revered as a symbol of rebirth and immortality -- its daily journey across the sky became an allegory of human life. Images of the dung beetle were incorporated into Egyptian art and religion: the god Khepera was always depicted with a scarab-shaped head, stones carved to resemble scarabs were placed over a person's eyes and mouth after death to protect the body from evil spirits, and scarab-shaped gems and icons were a recurring motif in Egyptian jewelry and other decorative artifacts.
The symbolic character of insects is also ingrained in many other cultures. To ancient Greeks, the goddess Psyche (represented by a moth) was a symbol of the soul or spirit. To the Chinese, a mantis symbolized cruelty and mystery. To Buddists, the cicada was a symbol of resurrection. To Egyptians, the fly represented valor (the "Order of the Golden Fly" was a military honor presented for outstanding bravery). But to the Hebrews, flies were the manifestation of evil -- a personification of Beelzebub, Lord of the Flies (Satan himself).
The religious and symbolic significance of these insects was often reflected in the art, literature, music, and dance of the times. Early renaissance artists, for example, sometimes included the image of a fly in religious paintings to illustrate the omnipresence of evil. The Chinese, who regarded the butterfly as a symbol of joy, used it extensively in their artwork. Love was often portrayed in the form of bees or butterflies, as in the 16th century painting "Venus and Cupid" by Lucas Cranach.
Many insects are valued simply for their beauty. Colorful beetles, alive
and tethered, are worn as brooches or ornamental pins in some parts of
Africa and South America. The irridescent wings of Morpho spp. butterflies
and Urania spp. moths are also crafted into beautiful jewelry and
other decorations. Insect imagery is commonly found in textiles, ceramics,
kitchenware, and even on the face of coins and postage stamps.
Boy with a Butterfly Net
by Henri Matisse
Insects appear in famous paintings of many artists dating back to the days of our cave-dwelling ancestors. They were commonly used as focal points in the delicate silkscreens of early Chinese and Japanese artists. They can be found (often with meticulous detail) in the floral still lifes created by Jan van Huysum and other 18th century Dutch realists. They also appear in the modern graphic art of Charles Harper and M. C. Escher. Flies and ants are common features of Salvador Dali's surrealistic landscapes, copper-plate etchings of butterflies are a hallmark of Anneli Arms, and Charles Burchfield is best known for his visualization of natural sounds (e.g. chirping crickets and katydids).
Many people regard insect sounds as a form of music. The Chinese sometimes
keep crickets as pets in bamboo cages in order to enjoy the chirping. In
fact, crickets were the inspiration for "El Grillo", a popular song written
by Josquin des Pres (16??) for one of Leonardo da Vinci's garden parties.
"El Grillo" was the first musical score to be printed on John Guttenburg's
moveable-type press. Robert Schumann's "Papillons" is a series of short
musical compositions written between 1829 and 1831. These melodies feature
fanciful changes of mood and direction as the music (or the butterfly)
flits from one scene to another. "Flight of the Bumblebee", written in
1900 as part of the opera "Tsar Saltan", is probably the best-known musical
score that evokes images of an insect. Its composer, Nikolai Rimsky-Korsakov,
is remembered for his great music -- few people even know that he was also
an avid insect collector.
Busy as a bee
Insects in Language and Literature
Although much of the religious and symbolic significance of insects has faded in the glare of modern science and technology, our language still reflects many traditional associations: busy as a bee, annoying as a fly, mad as a hornet. We still recognize the ant as a symbol of hard work, the lady beetle as a harbinger of good luck, and the butterfly as an object of transient beauty.
Insects and their underlying symbolism are prevalent in our literature (both lyric and prose). There are over 30 references to insects in The Bible, including three of the ten plagues on Egypt (flies, lice, and locusts -- Exodus, chapters 8-10). Buddhist and Islamic writings also include references to insects.
Secular writers have used insects as an effective contrapoint to human desires and aspirations. "To a Louse, On Seeing one on a Lady's Bonnet at Church" was written by Robert Burns (1785) as a sermonette on vanity and a satire of the social classes. His final stanza, in Scottish vernacular, includes a thoughtful admonition for humility:
"Metamorphosis", a novel by Franz Kafka, also makes a strong social
statement by portraying the fate of Gregor Samsa, a traveling salesman
who awakes one morning to find that he has been transformed into a cockroach.
On a lighter note, Archie the Cockroach and Jimminy Cricket are two of
the most famous insect "personalities" of all time. The character of Jiminy
Cricket was created by Ward Kimball, an animation artist for Walt Disney's
feature-length film "Pinocchio". This little "orthopteran" who played the
part of Pinocchio's conscience became a box office hit singing "When You
Wish Upon A Star". Archie the Cockroach was the brainchild of Don Marquis,
a newspaper columnist for the "New York Sun". Archie allegedly contributed
his wit and wisdom at night by jumping onto the keys of Marquis' typewriter,
one letter at a time. Since Archie could strike only one key with each
jump, his correspondence was limited to lower case letters and other symbols
that did not require use of the "Shift" key.
In the twentieth century, movies have become an important part of our
culture. Cinematographers usually portray insects as villains or monsters
[e.g., "The Fly" (1958), "Mothra" (1962), "Bug" (1975), and "The Swarm"
(1977)], and entomologists themselves don't fare much better [e.g., "The
Collector" (1965) and "Invasion of the Bee Girls (1973)]. Insects are often
included for their "shock" value, to set a "creepy" mood, or to provide
comic relief. Although realistic portrayals
of insects (and entomologists) are rare, there are a few outstanding exceptions:
e.g., the swarm of locusts in "The Good Earth" (1937), and various insects
in "Summer Magic" (1963). In contrast to the popular cinema, documentaries
produced for Nova, National Geographic, and various Public Television stations
include outstanding footage of insects in their natural surroundings. "The
Ruling Class" (WQED, Pittsburgh) and "Slaves to the Queen" (WNET, Boston)
are especially noteworthy.
Science and Technology
Much of what we know about anatomy, development, and ecology has been
learned just within the past 300-400 years. As recently as the mid 1800's,
it was widely believed that complex organisms sprang to life from inanimate
matter within their environment -- worms came from soil or wood, and maggots
came from the juices of decaying meat. An Italian biologist, Francesco
Redi, set the record straight in 1668 by demonstrating that flies had to
lay eggs on meat before maggots would develop, but the theory of spontaneous
generation persisted in one form or another until it was finally debunked
by Louis Pasteur's classic experiments in the early 1860's.
The study of insects, particularly their life cycles, physiology, genetics, and ecology, has contributed a great deal to our overall understanding of biology. In the late 1600's, Antoni van Leeuwenhoek, the Dutch microscopist who first described bacteria and protozoa, used the eye of a louse as his standard unit of measurement for microscopic observations because "it's size was ever constant". The geneticist's fruit fly (Drosophila melanogaster) has contributed much to our knowledge of chromosome structure, mutation, and sex-linked inheritance. Its four pairs of chromosomes have been mapped with over ten thousand individual genes. The first association between pathogens and disease grew out of Louis Pasteur's studies of silkworm diseases (1865-1870).
Our knowledge of physiology has been advanced by studying the processes
of growth and development in assassin bugs (Rhodnius spp.) and in
various silk moths (e.g., Bombyx mori and Hyalophora cecropia).
Population ecology has profited from studies of house flies, blow flies,
and darkling beetles. Toxicology relies heavily on flies, cockroaches,
and hornworms to assess the toxicity of insecticides. The study of insects
has also provided basic knowledge in nutrition, metabolism, endocrinology,
and neuromuscular physiology.
A knowledge of insect structure has even proven useful in non-biological professions. In 1983, engineers at McDonnell Douglas Corp. studied the legs of a grasshopper (Orthoptera) to help them design shock absorbers for a new jet fighter, the Hornet. Dr. Rodney Brooks at MIT's Artificial Intelligence Laboratory is developing six-legged robots with an electronic control system that is modelled after the distributed nervous system of insects. This approach, known as "subsumption architecture", has recently stimulated a great deal of interest (and controversy) in the world of robotics.
Law enforcement agencies have discovered that insects and other arthropods can furnish valuable evidence for criminal investigations. Specialists in forensic entomology can often deduce how, when, or where a crime
Medical and Therapeutic Value
During much of the seventeenth century, people in Europe believed that all plants and animals were created by God to either punish or serve humanity. They presumed, therefore, that any insect with no obvious detriment must possess some useful characteristic, often related to curing disease. As a result, insects (and other organisms) were carefully studied for their medicinal value and many species were incorporated into remedies that may (or may not) have actually worked.
At least a few of these drugs did contain pharmacologically active compounds. For example, blister beetles (family Meloidae) contain relatively high concentrations of cantharadin, a compound with notable effects on the urogenital system of vertebrates. Once prescribed as an aphrodesiac, cantharadin is now used to induce mating in some domestic animals and as a therapy for some disorders of the urinary tract.
During World War I, medics noticed that gunshot wounds infested with blow fly maggots seldom developed bacterial infections. Their observation led to the use of maggot therapy (sterile-reared fly larvae for cleaning necrotic tissue from deep wounds), and the later discovery of allantoin, a chemical secretion of the larvae that inhibits bacterial growth. Synthetically produced allantoin was commonly used as an antibacterial ointment until penicillin and other antibiotics became commercially available in the 1940's.
Honey bees (or their products) have been used for medicinal purposes since medieval times. This practice, known as apitherapy, still exists as a form of "alternative" medicine in Europe and other parts of the world. Some proponents of apitherapy use bee stings as a treatment for patients who suffer from arthritis, multiple sclerosis, lupus erythematosus, Parkinson's disease, and other auto-immune conditions. Recent evidence suggests that bee venom (or one of its components) has long-lasting effects on the human body, perhaps by increasing the body's own production of cortisol, an anti-inflammatory compound similar to cortisone but with fewer harmful side effects.
In the past few years, Chinese athletes have been setting new world records at an astonishing rate. Some people believe this success may be due, in part, to a diet that includes a tea-like beverage made from dried caterpillars (Hepialus oblifurcus) that have been killed by a fungus (Cordyceps sinensis). The Chinese have used this potion for hundreds of years. They claim that it reduces the physiological effects of stress on the human body and permits a more intensive training regimen.
Research has uncovered other substances with anti-viral, anti-fungal, and anti-inflammatory activity in a variety of other insects, and there are undoubtedly more beneficial compounds still waiting to be discovered. Some entomologists, such as Dr. Tom Eisner at Cornell University, have advocated a more methodical search for these new medicines. Eisner calls it "chemical prospecting"; he believes pharmaceutical companies will find enough new drugs in the class Insecta to keep them busy for many hundreds of years.
Next Page: Reasons for Success
Last Updated: 11 November 2008
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John R. Meyer
Department of Entomology
NC State University