The extinction of all species in the order Diptera, the true flies, would represent a profound ecological catastrophe. This single insect order contains an estimated 1,000,000 species, with over 160,000 formally described, encompassing familiar groups like house flies, midges, mosquitoes, and gnats. Flies are present in nearly every terrestrial habitat worldwide, and their disappearance would instantly remove a massive portion of the planet’s insect biomass. The absence of this diverse group would trigger a cascade of environmental failures that would fundamentally alter life on Earth.
The Breakdown of Natural Waste Systems
Fly larvae, commonly known as maggots, function as the primary cleanup crew for organic waste in countless ecosystems. These specialized consumers of detritus, carrion, and dung play an essential role in rapidly breaking down these materials. Without the voracious appetite of blow fly and flesh fly maggots, the decomposition of animal carcasses would slow dramatically, leading to the accumulation of unconsumed organic matter.
The black soldier fly larva (Hermetia illucens) is a prime example of this ecological efficiency, capable of reducing organic waste weight by up to 80% in under two weeks. This rapid consumption accelerates nutrient cycling, returning elements locked in waste back into the soil for use by plants. The failure of this waste management system would cause a sanitation crisis, particularly in warmer climates. Decomposing matter would proliferate, becoming a breeding ground for pathogenic bacteria and fungi.
Disruption of the Global Food Web
The biomass of flies and their larvae provides a year-round protein source for countless predators across terrestrial and aquatic environments. Their extinction would remove a foundational link in the food chain, leading to population crashes for species that rely heavily on them. Fish populations, including trout and bass, depend on aquatic fly larvae and emerging adults as a staple of their diet.
Birds like swallows, flycatchers, and many waterfowl would suffer massive declines due to the loss of their primary insect prey. Even commercially farmed animals, such as chickens, pigs, and farmed fish, now benefit from protein-rich black soldier fly larvae meal as a sustainable feed substitute. The abrupt removal of this massive food source, from the smallest spiders to the largest bats, would initiate a wave of secondary extinctions, drastically reducing global biodiversity.
Loss of Specialized Pollination Services
While bees are widely recognized as pollinators, flies are responsible for the reproduction of thousands of plant species, often in specialized ecological niches. Flies are important pollinators, contributing to the pollination of a large percentage of food crops. Unlike bees, flies often inadvertently transfer pollen while feeding on nectar, decaying matter, or putrid-smelling substances.
A consequence would be the loss of chocolate production, which relies almost entirely on minute flies called midges. These tiny insects are the only creatures capable of pollinating the complex, small, downward-facing flowers of the cacao plant. Beyond chocolate, flies are essential for the commercial production of other crops, including mangoes, onions, cashews, and avocados. Many plants have evolved flowers that mimic the odor of rotting meat or dung to attract fly species, a relationship that would cease to exist upon their extinction.
Impact on Human Science and Medicine
The extinction of flies would also eliminate several tools and model organisms used in human science and health. The entire field of forensic entomology would collapse, as it relies on the predictable life cycle and developmental rate of blow fly and flesh fly maggots to estimate the post-mortem interval (PMI) in criminal investigations. By determining the maggot species and its life stage—from egg to pupa—scientists can calculate the time elapsed since colonization, which often corresponds closely to the time of death.
In medicine, a valuable therapeutic option would be lost with the disappearance of Maggot Debridement Therapy (MDT). This therapy uses sterile larvae, most commonly of the green bottle fly (Lucilia sericata), to clean non-healing wounds like diabetic ulcers. The maggots selectively consume necrotic tissue and secrete antimicrobial compounds, a proven method that would no longer be available. Furthermore, the fruit fly (Drosophila melanogaster) is an important model organism in genetic and biological research, and its loss would halt countless studies in human development, disease, and heredity.