….the flowery leaf
wants not its soft inhabitants. The stone,
hard as it is, in every winding pore
holds multitudes. But chief the forest-boughs,
which dance unnumber'd to th' inspiring breeze
….even animals subsist
On animals, in infinite descent;
And all so fine adjusted, that the loss
Of the least species would disturb the whole.
James Thompson, Spring (1730).
There are over a million described species of insect in the world. It is likely that there are 10 million or more in actuality. We live in the Age of Insects, as it has remained since the Carboniferous Period more than 300 million years ago.
I have spent many years of my life studying, observing, and collecting insects, and in trying, with varying degrees of success, to help people see what makes ‘bugs’ so special. I have collected beetles on the high slopes of mountains, in chilly piles of conifer needles a few feet away from drifts of snow that lingered even into summer. I have swept my net through fields of fragrant sagebrush, picked marine beetles from between barnacle shells, examined cacti in the California desert and marveled at outsized iridescent leaf beetles in the Indonesian jungle. Those who know me know that my interests span a confusingly wide variety of topics, from historical linguistics to religion to ichthyology) and music, but my fascination for insects has remained a part of my life since I was a kid.
Last year I donated my collection of more than 10,000 beetles and bugs to Washington State University’s museum, a loss from which I won’t recover until I have amassed at least that many specimens again. But for me, collecting insects was never about ‘catching them all’, or an exercise in obsessive stamp collecting. In order to understand them, you have to know what they are. If you are interested in big butterflies or flashy scarabs, there is probably no need to make a collection. But my interest was in small beetles and true bugs, many of them only a few millimeters in length. In order to even know what you’re looking at, you have to get them under the microscope, and often make a few simple dissections. Why is this important? the answer is simple: insects are often extreme habitat specialists, and the presence of a particular species can tell the naturalist a great deal about a particular ecosystem. If you find in your net one species of the little rove-beetle Stenus, for example, you can be sure you are near a cool, clear-watered stream. If you find a different- to the naked eye nearly identical- Stenus, you could deduce the presence of a boggy wetland, or a grassy field. If, after many years of sampling a particular habitat, one species goes missing, it might indicate a drastic change in the habitat as yet unnoticed by the human eye- for instance, a gradual drying of the soil due to climate change, something which I believe is affecting beetle populations in the Pacific Northwest forests where I spent so much time.
The famous writer and biologist EO Wilson, who started his career as a specialist in the study of ants, liked to describe his favorite creatures as ‘the little things that run the world’, a phrase which could apply equally well to insects as a whole.
Exactly why insects have been so successful for so long, remains something of a mystery. Perhaps their ability to rapidly colonize and adapt to new habitats is a part of the reason. Perhaps it is the tendency to develop complex life-cycles which allow many species to dwell in different habitats at different times of life. Small size and fast reproductive cycles surely figure into it- and yet, spiders and centipedes, though ubiquitous, have far fewer species than insects.
One of the most remarkable traits of the insects as a whole is the intensely close ecological relationships they form with other organisms, particularly plants. The spectacular evolutionary radiation of flowering plants was driven by their relationships with insect pollinators, with many plants, such as most orchids, being pollinated by only one species of bee or moth. A beautiful wildflower meadow is made as much of bees and butterflies as it is of flowers- the two are linked by an unbreakable chain of ecology- the one would not exist without the other. The very oldest flowers are believed to have been pollinated not by colorful Lepidoptera, but by little brown beetles and flies. In the rainy Pacific Northwest, many spring flowers still are. The great yellow spadix of skunk cabbage, as well as the delicate white trillium lilies that for a few weeks cover the forest floor, play host to several species of rove beetles, pollen-eaters whose life is otherwise mysterious, appearing only in spring and disappearing with the fading of the early blooms.
Perhaps even more intriguing from a human perspective, many of our favorite food flavors come about through intricate insect-plant relationships. The flavors which we describe as ‘spicy’ in particular owe their pungency to the attempts of various plants to ward off herbivorous insects. The molecule that gives mustard, cabbage and wasabi their unique, biting spiciness is used by the plants to make leaves, seeds or root unpalatable to insect predation. No defense is perfect though. This family of plants- the Cruciferae- has an entire guild of insects specialized to feed on their flavorful leaves. The larvae of the infamous Cabbage White butterfly are among the most noticeable, but there are also several species of flea beetles which eat little else. All of these insects have, remarkably, developed the ability to digest the mustard oil which makes such plants inedible to others, and tasty to humans, thus beginning a rivalry which gardeners know all too well!
The aromatic compounds that give the tropical spices- cinnamon, cloves, nutmeg- their delicious flavor and scent are also, in nature, intended to keep away insect predators. Many trees suffer from the depredations of bark beetles. What better way to protect yourself than to secrete an irritating, fragrant compound directly in the young growing bark? Thus cinnamon came into being. Nutmeg and cloves produce similar substances in the fruits or, in the case of cloves, the flower heads themselves. The fact that humans, for some odd reason, have all over the world developed a taste for spice has worked out to the plants’ advantage- facilitating their spread to far-off countries and providing more protection from pests! European explorers in the New World were so taken with the chili pepper- a staple of South and Meso-American cooking for centuries- that they brought it with them back to Europe, and thence across the world, where over the half century since the heyday of the Spanish Empire it has been developed into a multitude of forms, and become an essential ingredient in the cuisine of Asia, often replacing black pepper and ginger as the main form of spice. The pungent flavor and aroma of onions and garlic derives from similar ecological pressure. So in a rather round-about way, we have insects to thank for many of the most delectable flavors loved by cooks across the world.
Insects are also one of the main components of the other end of ecosystems- the creation of soil, the decomposition of living form back into earth. When a tree falls in the woods, a closely knit communities of beetles and flies, mites and fungi break down the hard cellulose bit by bit, year by year, until eventually- a decade later, or a century-Nature is infinitely patient- a 200-foot tree has returned wholly to the brown soil. The larvae of wood-boring beetles drill into the wood, often spending years within the trunk before emerging to live as an adult for only weeks or months. Other insects colonize the tunnels made by large grubs; fungi take hold and slowly spread their filaments through the wood, gradually breaking down its fiberous structure. Termites excavate winding passageways, eating their way through the tree, with the help of gut-dwelling microbes digesting the very wood itself. Centipedes and beetles prey on the termites. Below the bark lives yet another community of weevils, bark beetles, rove beetles and many others, an ecosystem which changes and develops as the bark decays and loosens. All these myriad invertebrates provide food for larger animals- woodpeckers and tree-creepers, spiders and salamanders. In the very long term, they nourish the forest itself, for as the wood breaks down, the nutrients within it, released by the actions of fungi and beetles, are re-absorbed by the surrounding trees.
Not only fallen trees, but also decaying leaves, fungi and the bodies of animals are returned to the earth through the actions of insects. I have stood on the banks of the river when Salmon Season is over and seen how blow flies and beetles swarmed over the spent corpses of those noble fish cast up on the gravel shore. When all the dinosaurs died, think of the army of maggots and burying beetles that acted as the teeth and jaws of Mother Earth swallowing her lost children back into that dark living abyss, whence they would be reborn through countless generations of life.
The eccentric New Zealand-born biologist William Hamilton even wrote a moving, if slightly tongue-in-cheek, essay describing his wish to be, after death, consumed by burying beetles, and thus to be himself transformed by transference of matter into a swarm of brilliant shining insects.
There are so many insects that the naturalist will never run out of surprises. Studying insects is like listening to the greatest classical music- you can listen a thousand times and still discover something new. Most of the literally hundreds of thousands of bugs, beetles, butterflies and bees so far described are almost unknown beyond basic description- many are known only from a few specimens collected at lights or in insect traps, so knowledge of their behavior, ecology and general place in the great scheme of Nature remains a mystery. A day’s hiking through the rainforest, or even a walk in a temperate woodland, can almost always reveal some unknown piece of entomology to the careful observer.
Geology reveals evidence for several mass extinctions since the origin of insects hundreds of millions of years ago. While many important taxonomic groups- trilobites, marine reptiles, dinosaurs and many others- perished in these upheavals, insects always survived, and often diversified into new forms following the great ecological changes wrought by such events. The catastrophic event marking the division between the Permian and Triassic periods, for example, also opened up new habitats and niches which led to the origins of many common insect groups today.
Today it is believed that we are entering into another, largely human-caused, mass extinction. Few places on earth are today unaffected by humanity’s endless quest for resources, driven by a mad urge to consume, throw away and consume more. Garbage lies at the bottom of the Mariana trench miles below the sea’s surface, and litters the upper slopes of the Himalayas. Thousands of acres of rainforest are destroyed each year to make way for McDonalds beef cows and palm-oil plantations. Toxic waste from precious metal mines- elements used in the lucrative ‘green’ electronics industry- pollutes the rivers and oceans of the tropics. The list goes on, and there is no need to repeat these latter day lamentations- where now is a Prophet Elijah to rail against the depredations of a computerized multinational network of Wicked King Ahabs?
The result of the ecological disaster we are living through is the disappearance of species. Many invertebrates are so specialized for local conditions that, especially in extremely stable environments such as tropical rainforests, where a particular wooded valley might have remained the same since before the ice age, the loss of a few hectares of million-year-old forest might wipe them off the face of the earth, for ever. When a species disappears, it doesn’t come back. And here is a reason for the importance of those insect collections. Without them, we can’t even know what is being lost. Most insects cannot be identified accurately in the field without years and years of careful study of collections. Any environmental work to help protect the most vulnerable ecosystems must take into account their insect inhabitants, and it is difficult to do this without at least some knowledge of the insects’ classification and habitats.
Although insect populations are declining at an alarming rate across the world, there is little doubt that, in the long term, these incredibly adaptable creatures will survive, and continue to flourish, but we must not let that make us complacent as forests are cut down and meadows paved over. Life will recover- in Earth’s good time, which is not our time. Our time is measured in decades. Earth time is measured in hundreds of thousands and millions of years.
I opened this article with a quote from a rather peculiar poem that is now almost 300 years old, written by Scotsman James Thompson, now more or less forgotten but in his time wildly popular, and an obvious influence on the nature-focused Romantic-era poetry of a few decades later. Thompson must have been a keen observer of nature himself, for one verse- about insects, actually- ends with the remarkable lines:
And all so fine adjusted, that the loss
Of the least species would disturb the whole.
Again, that was written 3 centuries ago. This idea took nearly all of those three centuries to be ‘discovered’ and put into formal language by scientists, but it is one of the fundamental truths of ecology. The loss of the least species would disturb the whole- something that the entomologist, perhaps, knows better than anyone. It is by acting on such wisdom that we can, little by little, do our part to truly be stewards of the world we inherit, and preserve what remains of our environment not only for our own sake, but for that of every living thing with which we share this good earth.
Cody, this is one of the most enjoyable articles I have read in recent memory. The depth of your experience and wisdom is refreshing. In the last ten years I have become quite a plant person, having been drawn towards understanding more wild ways of being. That path, as you very well understand, has drawn me into such devotion for insects. As certain plants became well-known to me, as I became more and more present/observant, their insect partners became obvious. The relationship and synergy between these forms of life is a precious teaching on the interrelationships we all share. As my husband and I were driving south from the WI northwoods yesterday, I saw a billboard for The Insect Portraits of Levon Biss. I felt so much joy that there was someone elevating our collective vision of insects. And my last thought I’ll share here, I have long enjoyed Mary Oliver’s description of them: the small kingdoms …I enjoy the reverence for these kingdoms that your writing brings. Thank you!
Wonderful article!!! Thank you for sharing your incredible knowledge of entomology, nature and tying it all to literature. What a great perspective!