Many people find flies annoying as they fly everywhere, indoors and outdoors.
Many fly species serve as pollinators, even those overlooked by other pollinators. For instance, cocoa trees, essential for chocolate production, rely on these often disregarded flies for pollination [2].
Flies play a significant role in maintaining the ecological balance in nature and are a crucial part of the food chain, both as predators and prey. Some fly larvae hunt other insects or live as parasites. They are also an excellent source of food for other insects, such as fish, birds and mammals [4].
Fly larvae, or maggots as we call them, are the most critical larvae, as they break down and redistribute organic matter. In the process, the flies’ digestive excrement is released back into the soil as nutrient-rich fertiliser. The waste products excreted by the larvae nourish moulds and other types of fungi and plants. In this way, flies complement the ecological balance while playing a role in the food chain [3].
Humans also make use of flies in several areas. Fishermen use flies as bait. Criminal investigators can use them to determine the time of death by observing the presence of blowfly larvae, or maggots, as they are also known. Doctors can use fly larvae on patients to heal burns as they eat dead skin [2].
Flies can also be carriers of dangerous diseases. Scientists suspect that house flies can carry at least 65 diseases that infect humans. Some of the most common of these include food poisoning, dysentery and diarrhoea. House flies can also carry other diseases, such as anthrax, cholera, salmonella, tuberculosis and typhoid [5].
Key Functions
● Pollinators
● Decomposers
● Ecological balance
● Predators
● Parasites
● Food for other animals
Threat
● Changes in the use of land
● Logging
● Overgrowth & dehydration of habitat
Common species
Flies are found throughout the world and account for up to 100,000 species.
In Sweden, there are 4883 resident fly species.
Some species to discover in nature:
● Marmalade Hoverfly (Episyrphus balteatus)
https://artfakta.se/artbestamning/taxon/Episyrphus%20balteatus-200564 
● Sun Fly or European Hoverfly (Helophilus pendulus)
Inaturalist – Sun fly or European hoverfly
● Common Bog Hoverfly (Sericomyia silentis)
Naturspot – Common bog hoverfly
● Pellucid Hoverfly (Volucella pellucens)
Inaturalist – Pellucid hover fly
● Greater bee fly (Bombylius major)
Wildlife Trust – Greater bee fly
● Long Hoverfly (Sphaerophoria scripta)
Naturespot – Long hoverfly
● Batman Hoverfly (Myathropa florea)
Species Biodiversity Irland – Common Batman hoverfly
● Thick-legged Hoverfly (Syritta pipiens)
Naturespot – Thick-legged hoverfly
● Migrant Hoverfly (Eupeodes corollae)
Inaturalist – Migrant hoverfly
● Orange-belted Leafwalker (Xylota segnis)
iNaturalist – Orange-belted Leafwalker
Sources
- Artdatabanken – Two-winged – mosquitoes, hornets & flies
- Controlexterminating – The Purpose of Flies in the Environment
- Blog.csiro.au – Five reasons flies are awesome (despite being really annoying)
- Artdatabanken – Two wings in nature conservation
- Researchgate – Transmission of enteric pathogens by Musca domestica in and around hospital environment
May 2022, TÄNKOM | Revised January 2024 RETHINK
