Pest Guides

Autumn Fly

Musca autumnalis


Autumn Fly

  • Females are almost identical to the house fly, but males have an orange abdomen with black mark down the centre.
  • The female Autumn Fly is approximately 6–7mm in size, and is generally larger than the male.


  • Autumn Flies breed in animal dung in fields.
  • The Autumn Fly undergoes a complete metamorphosis with distinct egg, larva or maggot, pupa and adult stages.
  • The white eggs, which are about 1.2mm in length, are laid individually, but pile up in small masses. Each female Autumn Fly can lay up to 500 eggs in several batches over a three to four day period.
  • The life cycle of an Autumn Fly can be complete within 12–20 days depending on temperature, with as many as 12 generations occurring in one summer.


  • Autumn Flies affect both horses and cattle, and are usually seen on the face - frequently around the eyes.
  • At night, Autumn Flies rest on vegetation or man-made structures. Most daylight hours are spent feeding on plant sugars, the surface of manure deposits, or on animals.
  • On host animals, they obtain protein from nasal mucus, saliva, and tears. Autumn Flies have microscopic “teeth” on their mouth parts, which are used to stimulate the flow of tears and aid this feeding process.
  • They are strong fliers and are capable of travelling several kilometers, but most stay within the vicinity of their breeding grounds.