Since the inception of humankind, the ceaseless conflict between humans and insects has endured. For numerous creatures inhabiting the Earth, the emergence of Homo sapiens, the “bipedal beasts of terror” endowed with tool utilization and adeptness in cooperative combat, poses a formidable threat to their very survival. Along the arduous journey from birth to the advancement of civilization, humans can be regarded as “devoted to a myriad of transgressions,” be it herbivorous or carnivorous, docile or ferocious, as nearly all fall prey to the clutches of humanity, either hunted and consumed or domesticated as their own “compliant aides.” Nevertheless, it appears that humans truly have no respite from these inconspicuous insects, as they incessantly encounter harassment and assault.
To insects, which have inhabited the Earth for hundreds of millions of years, the advent of humans merely represents an “additional delicacy” in their existence. Lice, fleas, mosquitoes, and the like have been incorporated into their “sumptuous feast” upon the arrival of humanity. Furthermore, parasites such as hookworms, roundworms, and tapeworms swiftly discovered a congenial abode within the human body. Even during the era of agrarianism, when humans commenced leading settled lives and established relatively hygienic dwellings, not only did these vexatious insects persist, but the crops that humans diligently cultivated also enticed other unwelcome guests, such as locusts, aphids, borers, and other “consumers,” who launched attacks on human agriculture.
In the present day, humans possess profound insight and comprehension of numerous insect species, employing every conceivable measure, yet consistently failing to vanquish them. As conveyed by Liu Cixin in “The Three-Body Problem”: “Humans have exerted their utmost efforts to eradicate them, resorting to diverse poisons, aerial spraying, the introduction and cultivation of natural predators, the search for and annihilation of their eggs, and genetic manipulation to render them infertile; incinerating them, inundating them—every household possesses a pest-control ethos, and every desk harbors a weapon like a fly swatter to exterminate them… Bugs are never truly conquered.” To this day, mosquitoes reign as the primary culprits claiming human lives annually, responsible for over 700,000 deaths. In this grim tally, insects comprise half of the top ten.
Human Ingenuity in the Enduring Conflict
Throughout the annals of history, humans have employed an array of tactics to combat insects. Amidst this protracted struggle, people ascertained that insects harbor an intense aversion to smoke, thus fleeing from any smoky environs. Additionally, many insects exhibit remarkable olfactory sensitivity, being repelled by certain plant odors. Consequently, numerous civilizations employ smoke or the aromatic incense derived from burning plants to repel pests. In ancient Egypt, individuals burned resins, myrrh, and other spices to fumigate residences or storehouses where grains were kept, warding off insects. In pre-Qin Dynasty China, records exist of the utilization of mango grass for fumigating insects. By igniting the mango grass and filling the room with smoke, pest infestation in granaries was prevented.
Apart from extracting blood and disseminating pathogens, insects torment humans and devastate crops. Ancient China, a civilization endowed with conspicuous agricultural advantages, also made early investments in the battle against insect pests. During the pre-Qin era, the Chinese exhibited a cognizance of biodiversity. Furthermore, “The Doctrine of the Mean” proclaims the harmonious coexistence of all entities, fostering the Chinese inclination to glean insights from the natural ecology. By discerning patterns in nature and leveraging its mechanisms, they forged techniques to avert pestilence and maladies.
Foremost is the concept of “passive defense.” People ascertained that resilient and robust crops exhibit heightened resistance to pests and diseases. Thus, they meticulously screened and eliminated crops during the breeding stage, culminating in the refinement of selection techniques for wheat and grass. Concurrently, they pioneered the technique of deep plowing, which involves submerging nutrient-rich soil from beneath the surface and meticulously tilling it to enhance its quality. Furthermore, they discovered that crop rotation, intercropping, and mixed cropping can partially suppress pests and diseases, incorporating these practices into agriculture.
In addition to their “passive defense” strategies, ancient Chinese agriculturalists adopted a “proactive attack” approach. The first method employed was burning. Throughout the annals of my country’s agricultural production, the tradition of burning straw persisted. Though it may induce air pollution in contemporary times, in antiquity, this method served to incinerate pests and insect eggs in the soil while augmenting fertilizer efficacy. Additionally, in the growth stages of crops, people employed certain “pesticides” to exterminate insects, such as salt, sulfur, lime, arsenic, and more.
In the present day, as science and technology advance, human efforts to control pests have reached unprecedented heights. The advent of pesticides, coupled with the emergence of novel breeding techniques and cutting-edge pest sterilization methodologies, furnish updated weaponry in this ongoing war between humans and insects.
The Counteroffensive of Insects
Although humans have exerted their utmost to obliterate insects, these tenacious creatures remain elusive. From time immemorial to the present, their presence has been ceaseless: flies incessantly invade homes and assault food; inattentive individuals may find themselves beset by cockroaches emerging from sewers, bestowing an unwelcome “surprise”; and mosquitoes, seizing every opportunity, assail individuals “from head to toe” during summer months… However, these minor inconveniences in developed cities pose a genuine menace to human life in relatively underdeveloped regions, where insect-borne diseases claim the lives of millions annually. Flies, ticks, triatomine bugs, cryptid bugs, and other insects can unwittingly introduce viruses to humans. Moreover, mosquitoes, the foremost lethal insects, continue to pose a significant threat to human health and even life through the malaria they disseminate.
Yet, in comparison to these “guerrilla wars,” there exists an insect species that has persistently menaced humans on the “frontline battlefield” — the locusts. As one of the gravest agricultural catastrophes, locust swarms can rapidly devour all human crops, precipitating famine, a calamity that has profoundly impacted human history and civilization. Historical accounts frequently depict the calamitous locust plagues: “Vast tracts of crimson land, desiccated vegetation, humans and animals succumbing to starvation, with casualties too numerous to count.” Such descriptions evoke a shudder.
Throughout the annals of human history, records abound of the devastating consequences wrought by locust plagues. Wherever human civilization sprouts, locust plagues invariably follow, often instigating upheaval capable of altering the course of history. To this day, despite humanity’s mastery of advanced technologies, pesticides, and ecological sciences, locust plagues remain among the foremost causes of famine. Recently, a locust plague originating in East Africa in 2020 ravaged the continent, penetrated the Middle East, and even extended its ravages to Pakistan and India, wreaking havoc. In the face of this locust plague, humanity remains powerless.
Evolutionary Advantages as Weapons of Insects
Devoid of civilization and the capacity for invention, insects, over hundreds of millions of years, have acquired “unique weapons” through the process of gradual evolution. These weapons remain pivotal to their ongoing conflict with humans. Principal among these is their integration into the intricate tapestry of the ecosystem, rendering them an indispensable component of the ecological chain.
The tenets of pest ecological niche theory posit that organisms within ecosystems occupy distinct ecological niches. In any given ecosystem, each organism assumes a specific role and secures the requisite resources for survival, such as space, sustenance, water, and sunlight. Interactions among organisms can be categorized as competitive, symbiotic, or predatory. Eradicating pests inevitably engenders repercussions for other organisms within the ecological chain, consequences that prove difficult to forecast. For instance, consider the flies and mosquitoes that humans revile:They serve as a crucial food source for many other organisms, including birds, bats, amphibians, and fish. Eliminating these pests entirely would disrupt the food chain and have far-reaching ecological consequences.
Furthermore, insects possess remarkable reproductive capabilities, enabling them to multiply rapidly and overwhelm their adversaries. For example, mosquitoes can lay hundreds of eggs at a time, and their short life cycle allows for multiple generations within a single year. This rapid reproduction ensures their survival and persistence, even in the face of human efforts to control their populations.
Insects also exhibit a remarkable adaptability to changing environments. They can quickly develop resistance to pesticides and adapt their behavior to evade control measures. This adaptability is driven by their genetic diversity and high mutation rates, which allow them to evolve and overcome the challenges posed by human interventions.
Additionally, insects possess specialized physical features and behaviors that aid in their survival and defense. They may have protective exoskeletons, camouflage mechanisms, or the ability to mimic other organisms to avoid detection. Some insects have developed chemical defenses, such as the ability to produce toxins or release pheromones to communicate with their kin or confuse their enemies.
In summary, insects have evolved various weapons and strategies over millions of years to survive and thrive in their ecological niches. Their integration into complex ecosystems, rapid reproduction, adaptability, and specialized features make them formidable adversaries in the ongoing battle between humans and insects. While humans have made significant progress in pest control, it remains a challenging task to completely eradicate or control insect populations due to their evolutionary advantages and the intricate ecological web in which they are embedded.