Deer Flies | Identification & How to Get Rid of Deer Flies

Did you know that the deer flies are so populated that there are over 240 species of deer flies in the genus Chrysops?

Even though their distribution is worldwide, they have not been evident in:

  • Iceland
  • Greenland
  • Hawaii.

You may have heard of the house flies, the green bottle flies, etc but not the deer flies. Lucky for you we @pestclue have made this scarce info available for our readers, to keep you updated, and up to date.

Do not forget to drop your comments (inquiries/queries) as we will be anticipating them!


 What are Deer Flies?

Deer Flies
<strong>A Deer Fly<strong>

You may have heard about the deer flies, but you probably did not know that they are also referred to as the “sheep flies”.

They have a mouthpart specially modified for sucking, and so they are classified as sucking insects. They are considered pests since they feed on both humans and cattle, and are way bigger than the common houseflies but smaller than the horsefly.


How Do I Identify Deer Flies?

You may have seen a deer fly, but probably did not know it was the one! Well, lucky for you we have got ways of identifying the deer flies when you see them:

  • Antennae: The antennae of the deer fly is normally longer than its head.
  • Color: The bodies of these pests range between light brown, gray, yellow, and black stripings.
  • Wings: The wings of the deer fly are usually clear, with dark patches.
  • Eyes: One of the most noticeable features of the deer fly is its large, colorful eyes.
  • Size: Deer flies (adults) usually range from 0.25 to 0.33 inches long in size.


What is the Behavior of the Deer Flies?

Because they are flies, does not mean they will have similar behaviors with other fly species (common house fly, horsefly, etc). Let us go through some behavioral patterns of these bugs!


What Are The Stages Of Growth Of The Deer Flies?

Deer flies are fond of laying their eggs in rafts usually on moist or wet vegetations, and near water bodies such as stream banks, wetlands, ponds, etc.

The female deer flies lay an average of 100 to 700 eggs on moist, wet vegetations. The eggs hatch into Larvae and fall to the water bodies, where they feed on dead organic matter in the environment.

The larval stage lasts for a period of 1 to 3 years, and they move to the Pupal stage (it does not take weeks before they emerge into adults). These pests usually have a life cycle of 1 year, but some species will gracefully live for 2 to 3 years.

Deer flies are fond of laying their eggs in rafts usually on moist or wet vegetations. They go through 3 different stages:

  • As Eggs: They are laid in 100’s, and in batches on moist or wet vegetations.
  • At the Larval Stage: They feed on small creatures and organic matter close to water bodies. This stage will last for 1 to 3 years.
  • The Pupal Stage
  • As Adults: This is the final stage, and this usually occurs during spring or summer periods.

The males usually have distinctive features and behaviors from the females:

  • Male deer flies feed on pollen while female deer flies feed on blood, which is a basic requirement for the production of eggs (the females feed on mammals)


What Are The Feeding Habits Of The Deer Flies?

As mentioned earlier, the deer flies feed primarily on blood from mammals, while the males collect pollen (the males prefer to survive by feeding on nectar from flowers and plants).

Female deer flies are usually attracted to their preys by the following factors:

  • Carbon dioxide (CO2)
  • Scent
  • Sight
  • Motion
  • Size
  • Shape
  • Dark colors
  • Body Heat, etc

The females feed by using their scissor-like mandibles and maxillae to carve a cross-shaped marking, and then suck the blood. They are usually active during the day when there is adequate sunlight and when temperatures are beyond 295 Kelvin.

So what exactly do the deer flies eat? Below is a breakdown of what the deer flies eat:

  • Pollen (males)
  • Organic Debris (Aquatic Larvae)
  • Mammals (Humans, Deer, Pets, etc) (Females)


What are the Predators That Feed On The Deer Fly?

Despite being dramatically pesty, these pests also have predators that will gladly have them on the menu:


How do Deer Flies Bite?

Female deer flies have scissor-like mouthparts (like blades) that they use to mark a cross shape on the skin of their prey (mammals). When they have successfully cut the skin open, they suck the blood out of the exposed body part.

They like to feed on mammals in motion, and usually prefer to attack the head or neck of their hosts.

You should not interrupt them when their feeding though, as they will keep returning to the same host and repeatedly bite the mammal involved (well, except you exterminate them)


What are the Symptoms of a Deer Fly’s Bite?

Now that you can identify a deer fly, can you identify if you have been bitten by one? if ‘No’, then below are general symptoms of a deer fly’s bite:

  • Swelling, itchy feeling, and redness around the bitten area.
  • Constant itching and scratching of bite wounds will lead to secondary bacterial infections.
  • Symptom Reason for the symptom
    ·        Tularemia

    ·         Anthrax

    ·         Anaplasmosis

    ·        Equine infectious anemia

    ·         Hog cholera

    ·        Filariasis

    ·        Rash on the body

    ·        Wheezing

    ·        Swelling around the eyes

    ·        Swelling of the lips

    ·        Dizziness or weakness.

    The saliva of the deer flies contains anti-coagulants that may prevent blood clotting and lead to extreme allergic reactions (especially for people who are allergic to them).



How Do I Control A Deer Fly Infestation?

These flies rarely enter the house as they prefer moist and wet vegetations that are close to water bodies. You think that is good news right? well, it is not! (you cannot stay indoors all day)

It is now certain that deer flies (especially females) are pests, and a great threat to humans, pets, and other mammals. Below are possible ways of preventing a bite from these pests:

  1. Make Use of Liquid Repellents

Although it has not been certified on how effective these repellents can keep these pests away, it is good to try them out though, right?

The mixtures are made of:

  • Peppermint
  • Citronella
  • Lavender

2. Keep a Safe Distance

Did you know that deer flies are among the fastest insects in the world?

This makes it quite impossible to escape outrun them. So it is advisable that when you see one, instead of trying to outrun them try distancing away from them.

3. Put on Light-colored Clothes

These flies are most attracted to dark colors, so it is advisable to put on light-colored clothes as this will help in keeping them away for a while.

4. Avoid Water Bodies

Do not live close to water-bodied vegetations, as these pests (larvae) will obviously be lurking close by.

5. Always Wear Protective Hats

Since they are more attracted to the head and neck, it is advisable you wear hats to protect your head, and neck if possible.

6. Make a Sticky Hat Trap

Since they will be buzzing close to your hats, a sticky hat will surely glue them to itself, making you less vulnerable.



Deer flies should not be taken likely, as they can be a great nuisance to mammals (including humans, pets, etc)

Do not fail to drop your comments (inquiries/queries), as we will be anticipating your response!

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