Flies

Flies are insects in the order Diptera. They are characterized by a single pair of wings, with the hindwings reduced to small balancing organs called halteres. Adults typically have large compound eyes, short antennae, and mouthparts that vary by species, enabling feeding on liquids, nectar, decaying matter, or blood. Flies occupy a wide range of habitats across most of the world.

Flies undergo complete metamorphosis. Eggs are laid in appropriate substrates, such as decaying organic matter, animal waste, or living hosts. The hatched larva, or maggot, usually looks worm-like and feeds while growing. After reaching a certain size, the larva becomes a pupa, within which the adult develops. Development times depend on species and environmental conditions, especially temperature and food availability.

Ecology and behavior vary widely among flies. They serve as decomposers, helping recycle nutrients, and many species act as pollinators. Flies also provide food for a variety of predators, including birds and insects. They display diverse feeding strategies, with some species saprophagous, others herbivorous, hematophagous, or detritivorous. Some flies are agricultural pests or household nuisances, while others contribute to scientific research or forensics.

Interactions with humans range from beneficial to harmful. A number of fly species are disease vectors, capable of transmitting pathogens to humans and animals; examples include certain mosquitoes and other Diptera that spread malaria, dengue, sleeping sickness, or filarial parasites. Conversely, model organisms such as Drosophila melanogaster have been foundational in genetics and developmental biology. Overall, flies are a widespread and ecologically diverse group with both positive and negative impacts on ecosystems and human interests.