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What Is A Botfly? (Tips to Identify Botflies)

Botflies have been called the Aliens of the bug world, burrowing inside a living host, animal or human, to gestate until they burst out of the host’s skin. Except, they don’t actually kill or hurt the host during all the process.

This puts them firmly in the “gross but harmless” category.

Botflies don’t produce any infections in their hosts, don’t cause any harm (other than some swelling around the site), and eventually leave of their own accord to pupate and turn into adult botflies.

What is a bot fly

If you’ve been hearing a lot about botflies and want to know more about them, or you’re concerned your pets or livestock might have botflies, keep on reading and we’ll tell you all about them.

What Other Names Are Botflies Referred To As?

Botflies or bot flies (either spelling is correct) are known by the scientific name, Dermatobia Hominis.

They are mostly a South and Central American pest, so they are also called berne (Brazil), mirunta (Perú), moyocuil (México), mucha (Colombia), torsalo (Central America), and ura (Argentina). Additionally, they are also known as a warble fly, a heel fly, and gadflies.

Note: Southern California is the only part of North America where botflies are normally found.

Botflies also attack animals and each one has its own scientific name. For example:

  • Cattle – Hypoderma Bovis
  • Sheep/Goats/Reindeer – Oestrus ovis
  • Horses/Donkeys – Gasterophilus intestinalis (lives in the stomach)

Other names include cattle grubs (H. lineatum), sometimes known as heel flies.


Check out the video below for details on how to remove bot fly larvae from human skin.

What Are Botflies Commonly Mistaken For?

Due to their hairy bodies and coloration, botflies are often mistaken for a bumblebee or horsefly. They are, however, very rare in North America. Recent cases of botfly infestation have all been due to people traveling, vacationing, or working in South and Central America.

​Read More: Do Fruit Flies Bite?

Botflies Vs. Mosquitoes

One of the strangest symbiotic relationships in the world of entomology is the one between botflies and mosquitoes. During its short life, the female botfly will mate, then capture a mosquito in flight, lay eggs on it, and release it unharmed.

The eggs hatch into the larval stage when the mosquito bites a mammal (including you) and drop off onto the host. They will enter the host through the hole left by the mosquito bite or in the openings around hair follicles.

The botfly maggot or larvae molts several times during the infestation of the host. In humans, this infestation is known as cutaneous myiasis. Neither the host (human or animal) or the mosquitoes are harmed at any point in the process.

Read More: How to Get Rid of Mosquitoes

Botfly Vs. Yellow Fly

Due to its yellow coloration, the yellow fly, sometimes known as the batlass fly is sometimes mistaken for a botfly. Yellow flies, known in Belize as a doctor fly, are fierce biters.

They are quite distinct from botflies though since adult botflies don’t have the ability to bite anything. If you’re being bitten without mercy by a furry-looking yellow fly that looks similar to a bumblebee, you might think it’s a botfly but it’s not.

Botlfy Vs. Horse Fly

Horseflies are bloodsuckers, just like mosquitoes. They are frequent pests around cattle yards and livestock pens. They can reach sizes of up to 1-1/4 inches in length, much larger than the average botfly.

If a botfly is in the same area as a horsefly, it could lay its eggs on the bite marks left behind by the horse flies. It is a rare occurrence but it has been known to happen. 

Botflies and Mosquitoes

What Do Botflies Look Like?

botfly
Adult botflies have large bulbous heads covered with hair. The hair may be different colors, from black and white to reddish-orange. They are true flies, order Diptera, with only one set of wings. They are generally 1/2” to an inch long and have no functioning mouthparts at all.

The larvae are quite different. They are soft, lumpy ovals about 1-2 centimeters in length with backward-pointing spines all over their body to anchor them in place within their host’s body. They live just under the skin and the only sign of their presence is a boil-like swelling, known as a warble.

What Do Botflies Eat?

An adult botfly doesn’t eat anything. In fact, the adults are incapable of it because they don’t have any working or functioning mouthparts. Consequently, once they emerge from their cocoon they only live a few days until they die. They live just long enough to mate and reproduce.

The botfly larvae, inhabiting their host, live on the decaying tissue and fleshy matter that falls off the host due to the presence of the botflies. At each instar, when they molt and shed their skin, it too begins to decay and they eat it as well, in a form of self-cannibalization.

Are Botflies Poisonous or Dangerous?

No, not at all. A botfly infestation doesn’t harm the host. They need a breathing hole in the host’s skin, but once the botfly larvae emerge from the host’s skin, the skin lesion they leave behind heals within a couple of days.

Furthermore, they don’t transmit diseases or pathogens.

This happens whether it’s a human botfly or animal botfly. The life cycle and results are the same for both. Bluntly put, botflies are gross but not harmful.

Read More: How to Get Rid of Flies

Bonus: How to Handle Your Botfly Problem

If you traveled to another country and contracted botflies, you may be wondering what to do about them and how to prevent them in the future.

  • How to Get Rid of Botflies

If you have a botfly infestation inside you, removing them is easier than you might think. The furuncular lesion on your body is their breathing hole. If you cover it up, they won’t be able to breathe.

In South America where they are mostly found, the locals have come up with several methods of botfly removal. Cover the lesion with nail polish, petroleum jelly, or any kind of oil that cuts off their oxygen supply.

Within a few minutes, the maggot will emerge to get some air. Use some tweezers to grab the maggot and pull it the rest of the way out. It will resist and dig in its spines but eventually, you’ll be able to get it out. Then squash the horrid little thing.

Another method involves blowing cigarette smoke into a Coke bottle and placing the mouth of the Coke bottle over the lesion. Pretty soon the maggot will come out in search of fresh air. Again, use some tweezers to finish extracting it by force.

Please note: all these methods work equally well on livestock that may have been infected with botflies.

  • Best Pesticide To Eliminate Botflies

Adult botflies don’t live long enough for pesticides to be effective. They’ll emerge from their cocoons, mate, lay eggs, and die before the pesticide has had time to build up a lethal dose in their bodies.

Instead, get rid of the major method by which they spread – mosquitoes.

The best long-term pesticide for that is mosquito dunks, solid donut-shaped pesticides you drop in stagnant water where mosquitoes breed. The larvae eat the pesticide as it is slowly released in the water and they die.

Dead larvae can’t grow into adult mosquitoes and without mosquitoes, botflies can’t spread their eggs around to mammals. So, getting rid of mosquitoes, which no one likes anyway, will also help prevent the spread of botflies.

This is a long-term solution that doesn’t address the short-term but due to their incredibly short lifespan as adults, this is the only practical solution. For more information on getting rid of mosquitoes, see our article about it.

Read more: Top 4 Best Fly Traps Reviewed

The Final Round-Up

Botflies are a rarity in North America. If you’ve been to South America or Central America and were bitten by a mosquito, you might have been exposed to a botfly infestation. If you start developing a mostly painless swelling around a tiny hole, you might have them.

Removing botflies, whether on people or animals, is straightforward and easy. It’s a little bit gross but that’s all.

The only place in North America you might have to worry about botflies is if you live in Southern California. In that case, a good supply of mosquito dunks will work quite well to keep them from forming a symbiotic relationship.

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