Botflies are fascinating yet often unwelcome creatures that are found in various parts of the world.
These flies belong to the Oestridae family and rely on myiasis—the infestation of host skin—for their larvae’s nutrition.
In this article, you’ll discover where botflies are commonly found and how their locations might impact your outdoor adventures.
You may stumble upon botflies across North and South America, with certain species native to specific areas.
For example, the tree squirrel bot fly (Cuterebra emasculator) is found in Florida.
Another familiar species in the United States is Cuterebra fontinella, which inhabits most of the continental US, southern Canada, and northeastern Mexico.
When it comes to encountering these creatures, it’s helpful to understand their preferred habitats, since various types of botflies have a high degree of host specificity.
Understanding the geographical distribution and host preferences of botflies can help you stay informed about these fascinating parasites.
As you explore these infested regions, being aware of their presence enables you to better protect yourself and any animals in your care.
Overview of Botflies
Botflies are a group of insects belonging to the families Oestridae and Cuterebridae. These arthropods might make you feel a bit uncomfortable, but they play a significant role in their ecosystems.
Botflies rely on a unique method to infest their larval hosts: by using other species for travel, like mosquitoes, ticks, and flies.
Female botflies capture a mosquito, attach their eggs to its abdomen, and when the mosquito lands on a host, the eggs sense the temperature change, and the larvae emerge3.
These insects can affect a variety of hosts, including squirrels, dogs, cats, horses and even humans. Typically, the larval stage in the skin tissue lasts between 27 and 128 days.
After their life cycle in the host is complete, the larvae drop to the ground and undergo a pupation process before developing into adult botflies4.
Where Are Botflies Found? Distribution of Botflies
In the Americas, botflies are primarily found in the tropics, but their range extends to other regions as well.
In the United States, the most common bot fly, Cuterebra fontinella, occurs in most of the continental US, except Alaska.
Their range also includes southern Canada and northeastern Mexico1.
Other species, like deer botflies, or deer nose botflies (Cephenemyia spp.), can be found in North America2.
Moving further south, botflies are present in Central and South America as well, reaching all the way to northern Argentina2.
The human botfly, Dermatobia hominis, is found in Central and South America, from Mexico to Northern Argentina, excluding Chile.
It can also infest horses in Central and South America.
Some cases have also been reported in Europe. In the UK, bot species are more active in the South and Midland areas.
- Cuterebra fontinella: Continental US, southern Canada, northeastern Mexico
- Dermatobia hominis: Central and South America, Europe and UK
- Other botflies: Central and South America
Overall, their distribution seems to be largely limited to the Americas3.
Life Cycle of Botflies
Egg Stage
During the egg stage of the botfly life cycle, the female botfly deposits her eggs on a host, which could be a mammal such as rabbit, rodent, or even your pets like dogs.
Sometimes, the eggs are laid on surfaces near the host, or on a vector like a mosquito (the intermediary that carries botfly eggs). When these mosquitoes bite mammals, they transfer the botfly eggs to them.
Larvae Stage
In the larvae stage, the botfly larvae can hatch from the eggs after sensing the body heat of their host. They then burrow into the skin and start feeding on their host’s tissues.
During this parasitic stage, the larvae develop a breathing tube through a small hole in the host’s skin. The larval stage can last from 27 to 128 days, depending on the species and conditions.
Key features of the larvae stage:
- Burrow into host’s skin for nutrition
- Develop a breathing tube through host’s skin
- Parasitic stage lasts 27 to 128 days
Adult Stage
The adult stage of the botfly life cycle begins after the larvae mature and drop from their host. They then pupate in the ground for a period ranging from 27 to 78 days.
Adult botflies resemble bumblebees and have rudimentary or non-functioning mouthparts. Their primary purpose is to reproduce and lay eggs, continuing the cycle.
Botflies Infestation in Humans
Symptoms of Infestation
A botfly infestation, known as myiasis, occurs when a human botfly larva burrows under your skin.
You may notice a lump or swelling at the infestation site, which can be accompanied by itching or pain. If the larva is close to the skin surface, you might even see a small hole where its breathing tubes extrude.
Treatment Procedures
If you suspect a botfly infestation, consult your doctor for appropriate treatment. They may recommend an antibiotic to prevent infection.
Some at-home methods involve applying nail polish or petroleum jelly on the wound to suffocate the larva, making it easier to remove with tweezers.
However, it’s best to rely on medical guidance to ensure complete removal and recovery.
Botflies Infestation in Animals
Symptoms and Treatment
Botflies are parasites that infest animals like livestock, cattle, and horses. They lay their eggs on the host’s body, and the larvae burrow into the tissues, causing discomfort and painful wounds. Common symptoms include:
- Warbles: bulging lumps on the skin, where the larvae reside
- Irritation and itchiness around the affected area
- Secondary infections, which may sometimes lead to severe health problems or even death
If you suspect your animals have a botfly infestation, it is crucial to consult a vet.
They can help identify and remove the larvae, clean the wounds, and may prescribe medication to prevent infections or other complications.
In some cases, ticks may also be found in the wound area, requiring additional treatment.
Prevention Measures
To protect your animals from botflies infestation, follow these steps:
- Regular Checkups: Perform routine inspections to spot any botfly eggs, larvae, or warbles. If you find any, promptly contact your vet for assistance.
- Proper Grooming: Keep your animals clean and well-groomed. Regular brushing helps remove eggs or larvae before they can burrow into the skin.
- Control Pests: Maintain a tick- and fly-free environment by using insecticides and repellents approved for use on animals.
- Timely Treatment: If you spot any signs of infestation, act promptly to minimize the risk of spreading or complications.
| Prevention Measures | Pros | Cons |
|---|---|---|
| Regular Checkups | Early detection can minimize risks and complications | Time-consuming, requires a sharp eye for spotting eggs/larvae |
| Proper Grooming | Helps maintain overall hygiene, prevents potential infestations | Animals might resist grooming, takes time and effort |
| Control Pests | Protects animals from pests, promotes a healthy environment | Insecticides can be costly; some pests might develop resistance |
| Timely Treatment | Reduces complications and risk of spreading, promotes faster recovery | Vet visits can be expensive, treatment might be uncomfortable |
By following these prevention measures, you can proactively protect your animals from botflies infestation, ensuring their health and well-being.
Noteworthy Botfly Types
Dermatobia Hominis
The Dermatobia hominis, also known as the human bot fly, is a species found mostly in Central and South America.
It uses mosquitoes and other insects as vectors to lay its eggs on human skin. When the eggs hatch, larvae burrow under your skin and develop, causing irritation and pain.
Cuterebra Fontinella
The Cuterebra fontinella is another botfly species, commonly found in the United States and Canada.
This type mainly targets rodents, such as mice and squirrels, but can sometimes affect pets like cats and dogs. Its larvae, like other botflies, will live inside their host and cause discomfort.
Warble Flies
Warble flies, or heel flies and gadflies, are another group of botflies that can be found in various parts of the world.
These insects can cause “warbles” or lumps on their host’s skin, as their larvae live just under the skin’s surface. Livestock, such as cattle and sheep, are often the targets of warble flies.
Other Significant Types
There are also other significant types of botflies, such as:
- Oestrus ovis, also called the sheep nasal bot fly, which lays eggs in nasal passages of sheep.
- Gasterophilus intestinalis, or the horse stomach botfly, targeting horses and laying eggs on their legs.
These species, like the examples above, are parasitic and can cause discomfort in their hosts. Be aware of these botflies when traveling or caring for animals in the regions they inhabit.
Conclusion
In conclusion, botflies, belonging to the Oestridae and Cuterebridae families, are found across various regions, primarily in the Americas.
Their distribution includes North and South America, extending from the United States and Canada to Northern Argentina, with some species even reported in Europe.
These flies have a unique reproductive strategy involving myiasis, where larvae infest the skin of various hosts, including humans and animals.
Understanding their geographical distribution and host specificity is crucial for outdoor enthusiasts and pet owners to take preventive measures against botfly infestations.
Awareness of their presence in certain regions can help in better protecting oneself and animals under care, ensuring safety during outdoor activities and maintaining animal health.
Footnotes
