The Secret Life of Flies

062117_Blogheader StopFlies Fixed

Flies are one of the common seasonal foes of every equestrian. They annoy not only our horses, and other beloved pets, but cause us much frustration and hand wringing as well. But how much do you know about flies? This month the Mary’s Tack and Feed blog will be delving into all things fly related with our “Fly Wars!” and this week we’ll be looking at the buzzing creatures themselves.

In the world, there are approximately 120,000 species of flies, in North America we have about 16,000 types of flies. Some of the more common flies we’ll find in our homes and at the barn are: the common house fly, Flesh flies, Bluebottle flies (also known as blow flies), gnats (or no-see-ums), cluster flies, face flies, and the stable/horse fly.


The average female fly lays over 100 eggs in a batch and over the period of 1-3 days will produce 5-6 batches of eggs. That is a lot of flies!!! Female flies prefer damp, dark surfaces for egg laying close to decomposing organic material to provide food for her larvae. Within one day her eggs hatch and begin feeding around the egg laying site for the next 3-5 days. The fly larvae will molt several times during this stage until they are ready to pupate. Over 3-6 days within the safety of their pupae they will develop from their larval stage to their adult form and emerge as a full-grown annoying fly! Within 2-3 days of emerging the new female flies become capable of reproduction, starting the cycle all over again.

The average life expectancy of a fly (if we or nature does not intervene in the process) is as little as 7 days and up to 6 weeks. This period is highly dependent on the type of fly you are dealing with and the living conditions the fly has. Phorid and Fruit Flies both have the shortest life expectancy of all flies, 1-2 weeks. While House and Cluster Flies have much longer life spans, creeping upwards of 40 days.

Consider shortening their life span with a fly or insect trap

Proper sanitation/habitat destruction and pasture/manure management is the best way to manage flies in the home and stable. We’ll have more Fly Wars posts up this week for additional suggestions on how to protect yourself and your horses from flies this season. Mary’s Tack and Feed employees are always happy to help provide suggestions and tips on which products might be best for you.

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