The class Insecta represents the most diverse group of organisms on Earth, with over one million described species. While a small fraction of species are detrimental to human interests, the vast majority perform indispensable functions that support global ecosystems and human civilization. Exploring the positive impacts of these organisms reveals their profound influence on food security, commerce, and environmental health, often contrasting with the common perception of insects as pests or disease carriers.
Supporting Global Food Production
The stability of the global food supply chain is significantly reliant on the reproductive services provided by flying insects. Pollination, the transfer of pollen between plants, is an ecological service valued in the hundreds of billions of dollars annually. The worldwide economic value of insect pollination for major food crops accounts for nearly 10% of the total value of global agricultural food production. In the United States alone, the economic value of insect pollination reached $34 billion in 2012, highlighting the reliance of crops like almonds, apples, and blueberries on bees, butterflies, and other flying insects.
In addition to pollination, insects are systematically employed in agriculture as biological control agents to manage pest populations without synthetic chemicals. This practice involves using natural enemies like predatory lady beetles or parasitic wasps to suppress crop-damaging insects.
Biological Control Methods
The strategy known as augmentative biological control involves the mass-rearing and release of these beneficial species to boost naturally occurring populations. An example is the use of Aphidius colemani, a tiny wasp that injects an egg into an aphid, where the developing larva consumes the host from the inside, resulting in a hardened “aphid mummy.”
Inoculative release involves introducing small numbers of a control agent, such as the Trichogramma wasp, early in the season to establish a reproductive population that will control pests over time. These wasps target the eggs of many moth and butterfly pests, halting the life cycle before the destructive caterpillar stage begins. The classic biological control method introduces a natural enemy to combat an invasive pest that arrived without its native predators, such as the introduction of the Vedalia beetle to control the cottony cushion scale in California citrus groves. This integrated approach helps maintain pest populations below economically damaging thresholds, supporting sustainable crop yields.
Producing Valuable Materials and Food Sources
Several insect species produce materials that have been harvested and commercialized by humans for centuries, creating distinct economic goods. The ancient practice of sericulture depends on the domesticated silkworm, the larva of the moth Bombyx mori, which spins a cocoon made of a single continuous silk filament. This natural fiber remains a luxury textile appreciated for its strength and luster.
The production of shellac, a natural resin, originates from the female lac bug, Kerria lacca, which secretes the substance onto host trees as a protective covering. This raw material, known as sticklac, is processed into flakes used as a wood finish, a glaze for candies, and a binder in various industrial applications.
Another commercially important product is cochineal, a vibrant red dye derived from the defensive chemical, carminic acid, found in the female cochineal scale insect, Dactylopius coccus. These insects are cultivated on prickly pear cacti to produce the concentrated pigment used to color foods, cosmetics, and textiles. The ubiquitous honey bee, Apis mellifera, is valued not only for its pollination services but also for the production of honey, a natural sweetener, and beeswax, a versatile wax used in candles, cosmetics, and polishes.
The field of entomophagy, the consumption of insects, is growing as a sustainable solution to meet the increasing global demand for protein. Insects like crickets and mealworms are highly nutritious, offering protein levels comparable to traditional meat sources, along with healthy fats, vitamins, and minerals. Farming these insects requires significantly less land, water, and feed than conventional livestock. Furthermore, insects such as the black soldier fly larva are being mass-reared to convert organic waste streams into protein-rich feed for poultry, fish, and other livestock.
Essential Roles in Ecological Maintenance
Beyond their direct contributions to food and commerce, insects perform unseen ecological services that are foundational to maintaining healthy environments. The decomposition of organic matter is accelerated by insects, which physically break down dead plants, carrion, and animal waste.
Dung beetles are highly efficient recyclers that rapidly bury animal feces, a process that prevents the loss of up to 80% of manure nitrogen through volatilization. These beetles are considered ecosystem engineers because their tunneling behavior improves soil structure, creating channels that increase aeration and water infiltration into the ground. The tunnels also incorporate organic matter and nutrients into the subsoil, which enhances soil fertility and plant growth. Other decomposers, such as termites and certain fly larvae, break down dead wood and flesh, releasing nutrients back into the ecosystem for use by other organisms.
The sensitivity of many insect species to environmental changes allows them to function as bioindicators, providing a measure of the health of an ecosystem. Aquatic insects like mayflies and stoneflies are sensitive to water pollution, and their presence or absence can signal the quality of freshwater habitats.
The predictable life cycles of necrophagous insects, such as blow flies and carrion beetles, are utilized in forensic science. By analyzing the insect species present and the developmental stage of their larvae, forensic entomologists can accurately estimate the minimum postmortem interval, or time since death.