Flies are insects seen in a few episodes of the TV show.
Flies are insects of the Order Diptera. They are characterized by only having one set of wings to fly with. They are a very diverse, wide-ranging creature, occupying many ecological niches. Depending on the species, flies may be parasitic, carnivorous, carrion eaters, dung eaters, fungus eaters, nectar eaters, and so on. They are prey for a variety of invertebrates and vertebrates alike. They are also major pollinators, after bees and other Hymenoptera species.
In the How to Train Your Dragon Franchise, flies have no function for humans or dragons.
However, in reality, flies and their larval stages - called maggots - have a major impact on agriculture, both good and bad. They are used to some extent in cooking and food. Flies also can be disease carriers, but maggots can also be used beneficially in medicine. The Fruit Fly is a classic laboratory organism used in scientific studies.
In the episode "Viking for Hire", Gobber is exhibiting how his weapons can be used for purposes other than killing dragons. One of which is using a mace as a fly swatter. As he tries to hit a fly with the mace, he ends up destroying the table he was using, while the fly got away unharmed.
In the episode, "The Eel Effect", Toothless accidentally bites and swallows a Bloodvein Eel, causing him illness. His senses are heightened to negative proportions. He is able to hear the small buzz of a distant fly as a loud bothersome noise.
Flies are heard and seen (with difficulty) buzzing around some rather pungent and rotten desserts the Twins concoct for Mala when helping to plan her wedding.
As an Epithet
The term "maggot" is used occasionally in the Franchise as a derogatory term.
|“||Meal time, maggots!||”|
|— Outcast jailor in "Dragon Eye of the Beholder, Part 1"|
|“||Keep pulling, you maggots, unless you want to be giant eel chum!||”|
|— Savage in "Gone Gustav Gone"|