Entomology is the scientific study of insects, and its importance radiates into nearly every corner of human life. From the food on your plate to the diseases your doctor warns you about, from criminal investigations to the design of tiny flying robots, the work of entomologists touches agriculture, medicine, engineering, conservation, and public health. Insects themselves are the most species-rich group of animals on Earth, and understanding them has turned out to be one of the most practical branches of biology there is.
An Almost Incomprehensible Number of Species
The sheer scale of what entomologists study sets the field apart. Roughly one million insect species have been formally described and named so far, which already accounts for about half of all known living species on the planet.1PubMed. Estimating Global Biodiversity: The Role of Cryptic Insect Species But the described species are just the beginning. Several independent estimates have converged on a probable total of around 5.5 million insect species, meaning roughly 80 percent remain undiscovered.2PubMed. How Many Species of Insects and Other Terrestrial Arthropods Are There on Earth? When researchers factor in so-called cryptic species, which look identical to a known species under a microscope but are genetically distinct, the number could climb much higher still, with one analysis projecting upward of 21 million insect species.3Systematic Biology. Estimating Global Biodiversity: The Role of Cryptic Insect Species
This means entomologists are working on a puzzle where most of the pieces have not even been found yet. Entire families within beetle, fly, and wasp lineages remain poorly studied, and huge swaths of the tropics have barely been sampled. That gap matters because you cannot protect, manage, or exploit what you have not identified. Much of the field’s day-to-day work is simply cataloguing what exists, figuring out how species relate to one another, and documenting where they live before habitat loss erases them.
Keeping the World Fed
Insects are central to agriculture in ways most people only vaguely appreciate. Animal-based pollination contributes to about 30 percent of global food production, and bee-pollinated crops alone supply roughly a third of the total human diet.4PubMed Central. Overview of Bee Pollination and Its Economic Value for Crop Production In Europe, the dependency is even sharper: an estimated 76 percent of food crops and 80 percent of wild plants rely on insect pollination.5Environmental and Sustainability Indicators. Assessing the economic impact of insect pollination on the agricultural sector: A department-level case study in France Without entomologists tracking pollinator health, mapping which species visit which crops, and figuring out why colonies fail, modern agriculture would be flying blind.
Pollination is the most visible service, but insects also keep soil productive. Dung beetles break down animal waste and work nutrients back into the ground. Termites digest cellulose from dead wood and plant litter with the help of gut microorganisms, accelerating nutrient cycling in forests and grasslands.6International Journal of Advanced Biochemistry Research. A study to access the significant role of insects in decomposition and nutrient recycling These are not quaint ecological footnotes. Without decomposer insects, dead organic matter would pile up, nutrients would stay locked away, and the fertility of agricultural land would decline over time.
The Base of the Food Web
Insects are also the primary food source for a staggering number of other animals. Songbirds, bats, freshwater fish, lizards, frogs, and many small mammals depend on insects for the bulk of their calories, especially when raising young. Declines in insect abundance and biomass reported from around the world have raised real concerns about food limitation for insectivorous species.7PubMed. The effect of insect food availability on songbird reproductive success and chick body condition: Evidence from a systematic review and meta-analysis When insect populations shrink, the effects ripple upward through the food chain: fewer chicks survive, bat colonies thin out, and fish that feed on aquatic larvae lose a key protein source. Entomologists studying these dynamics are essentially monitoring the plumbing of entire ecosystems.
Disease, Mosquitoes, and Medical Entomology
Some of the most consequential work in entomology deals with insects that make people sick. Mosquito-borne diseases alone account for about 17 percent of all infectious diseases and kill roughly 700,000 people every year.8PubMed Central. Review of selected mosquito-borne diseases: arboviruses (dengue, chikungunya, Zika, West Nile, Japanese encephalitis, yellow fever) and parasitic diseases (malaria, lymphatic Filariasis) The list of diseases transmitted by mosquitoes is long: malaria, dengue, Zika, chikungunya, West Nile virus, yellow fever, Japanese encephalitis, and lymphatic filariasis, among others. More than 80 percent of the global population lives in areas at risk of at least one vector-borne disease, with mosquitoes being the largest contributor to that burden.9PubMed. The effect of global change on mosquito-borne disease
Medical entomologists study the biology and behavior of disease-carrying insects so that control programs can target the right species at the right life stage. That might mean identifying which mosquito species in a region carries which pathogen, understanding when and where females bite, mapping insecticide resistance, or developing new traps. Climate change is expanding the geographic range of many vectors, pushing species like Aedes aegypti (the primary dengue mosquito) into higher latitudes and altitudes. The entomological surveillance that tracks these shifts is what gives public health agencies the lead time to prepare.
Veterinary Entomology and Livestock
Insects are not just a human health problem. They impose enormous costs on livestock industries worldwide. Ectoparasites like horn flies, lice, ticks, and various biting flies infest cattle, sheep, and poultry, causing direct losses through irritation, blood loss, and stress, as well as indirect losses by transmitting diseases.10PubMed Central. Projected economic losses due to vector and vector-borne parasitic diseases in livestock of India and its significance in implementing the concept of integrated practices for vector management In the United States alone, livestock production losses from ectoparasite infestations have been estimated to exceed $2.26 billion annually. Research has shown that infested cattle retain less nitrogen, produce more stress hormones, drink more water, and gain less weight, suggesting that the total energy balance of an animal shifts when it is under constant pest pressure.11Journal of Animal Science. A review of ectoparasites and their effect on cattle production
Veterinary entomologists develop integrated pest management strategies, ranging from biological controls to targeted insecticide application, that help farmers reduce these losses without creating resistance problems or contaminating meat and milk supplies. The field is especially important in tropical regions where vector-borne livestock diseases like trypanosomosis and tick-borne fevers can devastate herds.
Forensic Entomology
When a body is found in an advanced state of decomposition, traditional methods for estimating the time of death become unreliable. Forensic entomologists fill that gap by analyzing the insect species present on remains and the developmental stages of their larvae. Carrion insect succession patterns, the predictable sequence in which different species colonize a body, have long been used in death investigations.12PubMed. Evaluating the utility of hexapod species for calculating a confidence interval about a succession based postmortem interval estimate By integrating information about seasonal insect activity, larval development rates, and local environmental conditions like temperature and humidity, investigators can estimate a minimum time since death even when other indicators have faded.13PubMed. Estimation of postmortem interval in decomposed remains using insect evidence: A report of two cases
The technique works because blow flies, for instance, arrive at remains within minutes to hours and lay eggs whose development through larval stages follows a temperature-dependent timeline. If you know which species is present, what instar (growth stage) the larvae have reached, and what the local temperatures have been, you can work backward to a plausible window for the time of death. This information can be critical in homicide cases where weeks or months have elapsed before discovery.
Biological Pest Control
Not all insects are pests; many are remarkably effective at controlling the ones that are. Parasitoid wasps, for example, lay their eggs inside or on pest insects, and the developing larvae consume the host. These parasitoids are diverse and abundant in natural habitats and are increasingly used in agricultural settings to suppress crop pests without heavy reliance on chemical insecticides.14PubMed. Parasitoids for biological control in dryland agroecosystems
Getting biocontrol right, though, requires detailed entomological knowledge. Research has shown that parasitoid wasps need to be adapted to the specific defenses of their target pest. In one study, wasps that had not been previously exposed to a particular bacterial symbiont carried by aphids had virtually no effect on aphid populations. But wasp lines that had been pre-adapted to the symbiont controlled aphids successfully, significantly benefiting plant growth.15PubMed Central. Prior adaptation of parasitoids improves biological control of symbiont-protected pests The implication is that biocontrol is not just about releasing the right predator; it is about matching the predator’s evolutionary experience to the prey’s defenses, a level of specificity that only entomological research can provide.
Insects as Food and Animal Feed
One of the fastest-growing intersections between entomology and sustainability is the farming of insects for food and feed. Edible insects require far less land, water, and feed than conventional livestock and emit lower levels of greenhouse gases. They can also be raised on organic by-products and food waste, fitting neatly into circular economy models.16PubMed Central. Unlocking the Potential of Insect-Based Proteins: Sustainable Solutions for Global Food Security and Nutrition
The numbers on feed conversion are striking. Yellow mealworms and house crickets can convert feed to edible product at ratios comparable to poultry, around 2 to 2.3 on concentrate feed, which is far better than pork or beef.17PLOS ONE. Feed Conversion, Survival and Development, and Composition of Four Insect Species on Diets Composed of Food By-Products Black soldier fly larvae, used primarily as animal feed, are even more efficient. Entomologists have also found that diet composition affects not just growth rate but the nutritional profile of the insects produced. Diets high in yeast-derived protein, for example, shorten larval development time, reduce mortality, and increase weight gain in mealworm species, all of which matter if you are trying to run a commercially viable operation.18PubMed. Growth performance and feed conversion efficiency of three edible mealworm species (Coleoptera: Tenebrionidae) on diets composed of organic by-products
Maggot Therapy and Other Medical Uses
The idea of putting fly larvae on a wound sounds medieval, but maggot debridement therapy is a modern, medically sanctioned treatment used worldwide. Larvae of the green-bottle fly are placed on chronic, infected, or necrotic wounds, where they clean away dead tissue and reduce bacterial load. Beyond debridement, there is accumulating evidence that maggot secretions actually promote healing by activating the migration of skin-repair cells, stimulating new blood vessel formation, and increasing the production of growth factors in the wound environment.19PubMed. Does maggot therapy promote wound healing? The clinical and cellular evidence Laboratory work has identified specific amino acid derivatives in maggot secretions that selectively boost the growth of endothelial cells, the cells that line blood vessels, which likely contributes to the wound-healing effect.20British Journal of Dermatology. Amino acid derivatives from Lucilia sericata excretions/secretions may contribute to the beneficial effects of maggot therapy via increased angiogenesis
Maggot therapy is just one example of bioprospecting in entomology. Insect-derived compounds are being explored for antimicrobial peptides, anticoagulants, and other bioactive molecules. The pharmaceutical potential of a group containing millions of species, each with its own chemical toolkit, is barely scratched.
Insect-Inspired Engineering
Engineers have long looked to insects for design ideas, and one of the most active areas of biomimicry involves flight. Insect wings use passive mechanical features, flexible hinges, elastic deformations, and vein-reinforced membranes, that allow highly efficient and maneuverable flight at small scales. Researchers are synthesizing what is known about these mechanisms to build flapping-wing micro air vehicles for applications like surveillance, search-and-rescue, and environmental monitoring.21PubMed Central. Passive mechanisms in flying insects and applications in bio-inspired flapping-wing micro air vehicles Work in this area spans aerodynamics, materials science, and actuation technologies, all grounded in a detailed understanding of how real insect wings work.22PubMed Central. Bridging Biology and Engineering: Unsteady Aerodynamics and Biomimetic Design of Micro Air Vehicles
Beyond flight, insect anatomy has inspired adhesive surfaces modeled on beetle feet, structural color in textiles drawn from butterfly scales, and ventilation systems based on termite mounds. Entomology feeds these projects by supplying the biological detail that makes the mimicry work.
The Fruit Fly and Genetics
Entomology’s contribution to fundamental biology is hard to overstate, and no single insect illustrates this better than the common fruit fly. Drosophila melanogaster became a cornerstone of genetics in the early twentieth century and remains one of the most widely used model organisms in the world. It is used not just for studying basic biology but for modeling complex human diseases, understanding how mutations alter cells, tissues, and organs, and testing new compounds with potential therapeutic applications.23PubMed Central. Drosophila melanogaster: How and Why It Became a Model Organism A remarkable number of Nobel Prizes in Physiology or Medicine have been awarded for discoveries made in flies, including work on chromosomal inheritance, embryonic development, circadian rhythms, and innate immunity. Without entomological research on a single tiny insect, our understanding of human genetics and disease would look very different.
New Tools for Monitoring Insect Life
The field is evolving rapidly in how it collects data. Traditional insect surveys involve traps, nets, and the painstaking work of pinning and identifying specimens under a microscope. These methods are still essential, but newer approaches are expanding what is possible. One promising technique combines drones with environmental DNA sampling: a commercial drone equipped with a swabbing probe autonomously collects genetic material from vegetation, and the samples are then processed using rapid portable sequencing. This non-invasive approach can detect which insect species are present on plant surfaces without trapping or killing a single specimen.24PubMed Central. Robot-Aided Measurement of Insect Diversity on Vegetation Using Environmental DNA
Even more striking, researchers have successfully detected insects from airborne environmental DNA, genetic traces left floating in the air. This technology could become a powerful tool for monitoring pests, invasive species, endangered populations, and disease vectors over large areas without direct observation.25Environmental DNA. Airborne environmental DNA metabarcoding for the monitoring of terrestrial insects—A proof of concept from the field These tools do not replace traditional taxonomy, but they dramatically increase the speed and scale at which entomologists can survey biodiversity.
Invasive Insects and the Cost of Getting It Wrong
When insect species establish themselves outside their native range, the economic damage can be enormous. Invasive insects cost a minimum of $70 billion per year globally in damage to goods and services, with an additional $6.9 billion in associated health costs.26Nature Communications. Massive yet grossly underestimated global costs of invasive insects Those figures are considered conservative. The authors noted that rising temperatures, growing human populations, and intensifying international trade will allow costly species to spread into new areas, but that substantial savings could be achieved through better surveillance, containment, and public awareness.
Managing invasive species requires early detection, rapid identification, and an understanding of the invader’s biology that is deep enough to design effective interventions.27PubMed Central. Managing invasive species This is entomology’s bread and butter. Whether the problem is the emerald ash borer decimating North American forests or the Asian tiger mosquito expanding its range across southern Europe, the first responders are almost always entomologists equipped with traps, molecular identification tools, and knowledge of the pest’s ecology in its native habitat.
Social Insects and Complex Behavior
Some of the most sophisticated behavior in the animal kingdom occurs in insects. Ants, bees, termites, and some wasps form colonies with division of labor that mirrors the specialization of cells in a body. In eusocial wasp colonies, for instance, queens and workers perform clearly distinct roles: queens focus on dominance behaviors and soliciting food, while workers handle foraging, building, and colony defense. Among workers themselves, younger individuals tend to perform tasks inside the nest while older workers take on riskier foraging duties outside.28PubMed Central. Division of labor in colonies of the eusocial wasp, Mischocyttarus consimilis
Studying insect sociality has contributed directly to evolutionary theory, economics, and even computer science. Ant colony optimization algorithms, inspired by the way ants find shortest paths to food using pheromone trails, are used to solve routing and logistics problems. Understanding how insect colonies make collective decisions without any central control continues to inform thinking about distributed systems and emergent intelligence.
Silk, Dye, and the Renaissance Economy
Entomology’s cultural and economic roots go deep. During the Renaissance, much of the wealth that funded European politics and patronage came from insect-derived products: honey, silk, and cochineal dye, the last of which was one of the most valuable exports from the New World. The devastating plagues of earlier centuries, spread in part by fleas, reshaped European society by encouraging the later rise of a middle class. And as the period’s intellectual culture shifted away from symbolic readings of nature toward direct observation, the study of insects moved from religious allegory to something recognizably scientific.29Bloomsbury Cultural History. A Cultural History of Insects in the Renaissance Modern entomology inherited that transition, and the field has never stopped oscillating between pure curiosity about insect biology and the urgent practical need to manage the species that shape human welfare.