Exploring the Habitats of Botflies: What You Need to Know

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Botflies are fascinating insects that have a unique life cycle involving parasitic relationships with mammals. They belong to the Cuterebridae family and can be found in various regions depending on the species.

Generally, these flies inhabit warmer areas with a significant presence of their preferred hosts, such as rodents or lagomorphs, like rabbits and hares.

As you explore the world of botflies, you’ll discover that some species are found in places like North America, Central America, and South America, with certain species being more common in specific regions.

Botfly Laying Eggs. Where Do Botflies Live

For instance, Cuterebra fontinella is prevalent in the United States and southern Canada, while other species from the Cuterebra genus might be more common in other locations source.

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Understanding where botflies live and their reliance on specific host animals can be helpful in taking proper precautions to avoid the potential discomfort caused by these insects.

Keep in mind their distribution and habitats as you delve further into this intriguing topic.

Classification of Botflies

Botflies belong to the family Oestridae within the order Diptera and class Insecta under the phylum Arthropoda and kingdom Animalia.

They are parasitic flies, and their larvae live inside living mammals. There are various species of botflies, each associated with specific hosts and having unique characteristics.

Some common species of botflies include:

  • Dermatobia hominis: This species mainly targets humans and other mammals. The female botfly uses mosquitoes as a vector to attach its eggs, which then hatch on the host’s skin due to the warmth1.
  • Oestrus ovis: Also known as sheep botfly, primarily targets sheep nostrils, causing nasal myiasis2.
  • Cuterebra fontinella: This botfly species is commonly found in the Northeastern US, Southern Canada, and most of the continental US3. Rodents like squirrels and rabbits are their primary hosts.
How to Get Rid of a Botfly in a Dog

Some major subfamilies found under the family Oestridae include Cuterebrinae, Gasterophilinae, and Hypodermatinae, which consist of species like:

  • Gasterophilus: These are also known as horse botflies. They lay their eggs on the host’s hair, and the larvae parasitize horses’ stomachs4.
  • Hypoderma lineatum: Also called cattle grub, this species targets cattle, causing warbles under the animal’s skin5.
  • Cephenemyia: This group of botflies, known as deer nasal bots, attack deer by laying their larvae in the nostrils6.

The following table compares some essential characteristics of various botfly species:

Scientific NameCommon NamePrimary HostParasitic Location
Dermatobia hominisHuman BotflyHumansSubcutaneous tissue
Oestrus ovisSheep BotflySheepNasal cavities
Cuterebra fontinellaRodent BotflyRodentsUnder skin
GasterophilusHorse BotflyHorsesStomach
Hypoderma lineatumCattle GrubCattleSubcutaneous tissue
CephenemyiaDeer Nasal BotDeerNasal cavities

In conclusion, botflies are diverse, parasitic creatures, with various species targeting specific hosts and causing unique infestations.

Physical Characteristics

Botflies are known for their chunky, beelike appearance. They can vary in size and color, but they typically have rounded heads. Let’s take a look at some defining features:

  • Size: Botflies are not particularly large, but they are robust and can be quite noticeable.
  • Appearance: These insects resemble bees, and they often have black or dark-colored bodies.
  • Eyes: Botflies are equipped with large, compound eyes, which help them locate their hosts.
  • Mouth: Their mouthparts are adapted for feeding on nectar as adults.
  • Nose: Botflies don’t have a nose like mammals. Instead, they have antennae that function as sensory organs.
  • Breathing: Like other insects, botflies breathe through tiny tubes called tracheae, which are connected to spiracles on the sides of the body.

Remember that botflies may not be the most appealing creatures, but they are fascinating in their adaptation and overall appearance.

Life Cycle of Botflies

Eggs

Botflies begin their life cycle as eggs. Female botflies capture a mosquito, tick, or other fly and attach up to 24 eggs to its abdomen before releasing it.

When the carrying mosquito lands on a host’s skin, the abrupt rise in temperature triggers the eggs to hatch within days, resulting in tiny larvae entering the host’s skin through the mosquito bite or hair follicles.

Larval Stage

Next, the larvae continue to burrow into the host’s skin, where they enter the larval stage. The larvae live just under the skin, forming a bulge called a “warble.”

This process can last anywhere between 27 and 128 days, depending on the species of botfly. Typically, there’s a small hole in the center of the welt through which the larva’s breathing tubes extrude.

During the larval stage, some characteristics of the botfly larvae include:

  • Short and pudgy in appearance
  • Segmented body
  • High degree of host specificity

These features enable them to survive inside the host’s body.

Pupal Stage

After completing the larval stage, the botfly larvae drop to the ground, where they continue developing in the pupal stage.

This stage lasts between 27 and 78 days. The botfly pupae transform into adult flies within a protective case called a puparium.

Adult Flies

When the pupal stage is completed, the adult botflies emerge from their puparium, ready to mate and lay eggs on their next host.

Adult botflies resemble bees in appearance and have rudimentary or nonfunctioning mouthparts, as they do not feed or take in nutrients. Their main purpose is to reproduce and continue the cycle.

To summarize, the life cycle of botflies can be broken down into the following stages:

  • Eggs: Attached to mosquitoes or other flies by female botflies
  • Larval stage: Lives inside the host’s skin for 27 to 128 days
  • Pupal stage: Lasts between 27 and 78 days on the ground
  • Adult flies: Bee-like in appearance, focused on reproduction

Where Do Botflies Live?

Geographical Distribution

Botflies are primarily distributed across the Americas, with their range extending from North to South America.

In North America, you can find botflies in the United States and Canada, while they are native to Central and South America, specifically in tropical and subtropical regions.

It is worth noting that botflies are not commonly found in Europe.

During their life cycle, they require specific habitats to thrive. They lay their eggs on host animals or near their nests, burrows, or hiding places. The eggs then hatch into larvae, which infest host animals like mammals.

The distribution of botflies is dependent on the presence of suitable hosts. Some botfly species are more prevalent in certain regions due to the availability of specific mammal species.

For example, the human botfly, Dermatobia hominis, is commonly found in Central and South America, where it infests the skin of mammals, including humans.

To summarize, botflies can primarily be found across the Americas, with a larger concentration in Central and South America. Their habitat is heavily influenced by the availability of suitable hosts in the regions they inhabit.

Host Interaction

Infestation in Mammals

Bot flies are known parasites that target mammals. The larvae live inside the bodies of various mammals, causing infestations.

These flies interact with their hosts indirectly, usually through contact with fur. Livestock and pets are common hosts for bot fly larvae.

In most cases, a botfly larva burrows under the skin of a mammal host, causing swelling and irritation. The infestation can be uncomfortable, often leading to a visible bulge on the skin, called a warble.

The larva breathes through a small hole in the center of the warble source. If you suspect your pet may be hosting bot fly larvae, consult your vet for guidance on removal and treatment.

To minimize the chances of bot fly infestation in pets, follow these strategies:

  • Routinely groom your pets to check for any signs of larvae.
  • Keep your pets indoors during peak bot fly season.
  • Use insect repellent on your pets when they are outdoors.

Human Botfly Infection

Although botfly infestations in humans are rare, they do occur.

A human botfly infection can happen when the larvae come into contact with your skin, typically through an open pore. In some cases, the larvae may burrow into other areas, such as the eye.

If you develop a human botfly infection, you might experience swelling, irritation, and discomfort at the site of infestation.

The larvae usually expel themselves after approximately 6 weeks, but you should seek medical attention if you suspect an infection, as a healthcare provider can remove the larva and treat the site to prevent complications.

Here are some tips to reduce the risk of human botfly infections:

  • Apply insect repellent when traveling in areas known for bot flies.
  • Wear long pants and protective clothing to minimize skin exposure.
  • Check your body regularly for ticks and other insects when spending time in regions where bot flies are prevalent.

Prevention and Treatment

To prevent botfly infestations, it’s essential to take some precautions. Using an insect repellent is one way to protect yourself from these parasitic flies.

Make sure to apply repellent on exposed skin, as it can deter botflies from landing on you.

Bot Flies in Squirrels

You can also use a net to protect yourself, especially when sleeping outdoors in areas where botflies are prevalent. Covering your bed and resting areas with mosquito nets helps reduce the chances of encountering these pests.

When it comes to treatment, early removal of the botfly larva is crucial to avoid complications.

If you suspect a botfly infestation, it’s best to consult a medical professional or a vet for animals. They will provide the necessary guidance for safe and effective removal.

Keep these tips in mind:

  • Apply insect repellent on exposed skin
  • Use nets to cover sleeping areas
  • Consult a medical professional or vet for larva remova

Botflies in the Ecosystem

Botflies are fascinating yet sometimes unsettling insects that play a unique role in the ecosystem. These beelike flies belong to the Oestridae family, and they rely on myiasis, an infestation of host skin, for larval nutrition.

You may have heard of botflies by several other names such as warble flies, gadflies, or heel flies. What makes these insects stand out is their dependence on mammals as hosts.

Botfly larvae live within animals, whereas adult flies do not cause harm to mammals.

To understand botflies better, let’s look at a few key features:

  • Habitat: You can find botflies in various regions, particularly in North America, where species like the deer botfly (Cuterebra fontinella) are common.
  • Life cycle: Their life cycle begins when adult females lay eggs on plants or other surfaces. The larvae enter a host, such as a mammal, by burrowing into their skin.

As the larvae grow, they form a warble, a visible lump under the skin with a tiny hole for breathing. Eventually, the larvae leave the host to pupate and turn into adult flies.

It’s useful to compare botflies with other blood-feeding insects like mosquitoes and ticks. Here’s a simple comparison table:

InsectFeeding MethodLife Stage That Feeds on HostHost Harm
BotflyMyiasisLarvaeModerate
MosquitoBloodAdultLow
TickBloodLarvae, Nymph, AdultModerate

Botflies, mosquitoes, and ticks differ in the way they interact with their hosts.

While mosquitoes and ticks actively seek hosts for blood meals, botfly larvae rely on passively entering their host, often when the host brushes against botfly eggs on vegetation.

Adult botflies do not feed on blood, unlike adult mosquitoes and ticks.

In conclusion, botflies are an intriguing group of insects which have unique biological strategies focusing on mammals as hosts for their larvae.

Although their presence might be unsettling, they contribute to the balance of the ecosystem and showcase the amazing diversity of nature.

Impact on Livestock and Domestic Animals

Botflies can cause significant issues for livestock and domestic animals. These flies belong to the family Oestridae and have several species that target different hosts.

As a young botfly matures into a larva, they infest mammals such as cattle, horse, sheep, and even pets like dogs and cats.

Hosts and infestations

Botflies use various mammals as hosts. Some common hosts and their respective botfly species include:

  • Cattle: suffer from cattle grub caused by Hypoderma lineatum
  • Horses: get infested with Gasterophilus species
  • Sheep: face Cephenemyia infestations
  • Pets (primarily dogs): host Cuterebrinae species

Health impacts on animals

When botflies infest mammals, they can cause a range of health issues, such as:

  • Respiratory complications in sheep due to nose bot infestations
  • Pain and irritation caused by burrowing larvae in the skin
  • Secondary infections and abscesses at the site of infestation

Veterinary concerns

Vets play an essential role in treating botfly infestations in domestic animals. Early detection and accurate treatment can prevent severe health issues and economic loss for livestock owners.

Prevention and control measures

  • Regularly inspect your animals for signs of infestation
  • Use appropriate insecticides and repellents
  • Maintain good sanitation and hygiene practices in animal housing areas

In conclusion, botfly infestations can negatively impact livestock and domestic animals’ health and productivity. By being proactive and taking preventive measures, you can protect your animals from these troublesome pests.

Conclusion

In conclusion, botflies, belonging to the Oestridae family, are a group of parasitic insects with a unique life cycle that significantly impacts various mammals, including humans, livestock, and pets.

These flies are predominantly found in the Americas, from North to South, thriving in environments where their specific host animals are present.

Species like Dermatobia hominis, Oestrus ovis, and Cuterebra fontinella, each have distinct host preferences and geographical distributions, showcasing the diversity within this family.

Footnotes

  1. https://www.ncbi.nlm.nih.gov/books/NBK559223/
  2. https://mdc.mo.gov/discover-nature/field-guide/bot-flies
  3. https://extension.unh.edu/resource/bot-flies-fact-sheet-0
  4. https://livestockvetento.tamu.edu/insectspests/bot-flies/
  5. https://www.pgc.pa.gov/Wildlife/WildlifeHealth/Pages/BotsandWarbles.aspx
  6. https://mdc.mo.gov/discover-nature/field-guide/bot-flies

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about bot flies. Scroll down to have a look at some of them.

Letter 1 – Bot Fly Carnage

This bug is big…
Dear Bugman,
I found this bug on our inside garage window, Buffalo, WY (high desert). I thought the noise must be coming from a large bee or something because of the loudness of the buzzing. I have looked some on the internet, but can’t seem to find a match. I hope some of the pics are helpful. It is an inch long from front to back of the wing. If you look it in the face, it looks like a bulldog.It has a kind of shell over its thorax, similar to a beetle. It’s mainly curiosity to know what it is, as we have only seen one. However, we do have small children and a dog, so if it’s a nasty, I need to know. Thanks!
darla. Buffalo, WY

Hi Darla,
This amazing creature is a Bot Fly or Warble Fly. The larvae of Bot Flies are endoparasites. Most North American species have rodents as host, but tropical species are human parasites. Bot Flies are in the family Oestridae, and New World species are in the subfamily Cuterebrinae. Though there is a Central American species of Bot Fly that will parasitize humans, the North American species are harmless unless you are a squirrel or rabbit.

Letter 2 – Bot Fly

additional bot fly pics
Mon, Apr 13, 2009 at 12:02 PM
I saw that you posted some bot fly pics, but they were a little fuzzy. Here are a few I took that are a little more detailed. Perhaps not the exact same kind of bot fly, but pretty similar. There appear to be three tiny eyes between its two big compound eyes.
Vince
Northern Indiana

Bot Fly
Bot Fly

Hi Vince,
Thanks for sending us your Bot Fly images.  Now people can understand why the Interested Mountain Girl thought it looked like a mutant.

Letter 3 – Rabbit Bot Fly

never seen this one!
August 18, 2009
I was out shooting at Goose Lake Praire in Illinois and came across this red eyed black and grey bumble bee looking bug.Ive never seen one before …any ideas? One friend thought it was a bee fly but I cant find any photos that look like mine?! Also it looks like it maybe laying orange eggs or maybe thats part of the plant?
Denise
Illinois

Bot Fly Ovipositing
Rabbit Bot Fly Ovipositing

Hi Denise,
Someone has been hard at work on BugGuide identifying all the Bot Flies in the genus Cuterebra to the species level.  We do not have the necessary skills to perform that task for you.  Bot Flies are mammalian ectoparasites and they are generally very host specific.  Once we took a better look at your photographs, we realized that you caught this female Bot Fly in the act of ovipositing, or laying eggs on the grass.  We would need to further research this, but we believe the eggs hatch and then the maggots would attach to a passing/grazing host.

Bot Fly
Rabbit Bot Fly ovipositing

Comment from Karl
Daniel:
I think you are right on all points Daniel, except perhaps the ectoparasite part. It does look like a Cuterebra spp. which are opertunistic parasites of small mammals. According to the online Merck Veterinary Clinic (http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/71500.htm): “Adult Cuterebra flies are large and bee-like and do not feed or bite. Females deposit eggs around the openings of animal nests, burrows, along runways of the normal hosts, or on stones or vegetation in these areas. A female fly may deposit 5-15 eggs/site and >2,000 eggs in her lifetime. Animals become infested as they pass through contaminated areas; the eggs hatch in response to heat from a nearby host. In the target host, the larvae enter the body through the mouth or nares during grooming or, less commonly, through open wounds. After penetration, the larvae migrate to various species-specific subcutaneous locations on the body, where they develop and communicate with the air through a breathing pore. After ~30 days, the larvae exit the skin, fall to the soil, and pupate.” Sounds a bit nasty!  K

Hi Denise,
This is a female botfly, Cuterebra buccata which is a rabbit bot. Its host is generally Sylvilagus floridanus (and maybe other species of Sylvilagus in some areas). The larvae are sometimes seen in the neck or shoulder, and/or rump and hip of the rabbit. The red marks in the eyes are only observed in rabbit bots, and your location in IL helps narrow it to a few species. Luckily there is just enough of the white lower face showing in your photo to narrow it to C. buccata. They are not very often seen laying eggs, so nice to catch that on film.
equalrights4parasites

Comment from Eric Eaton
Daniel:
That is so awesome!  I know the guy who is working on Cuterebra, and I forwarded him your message.  His name is Jeff Boettner and he works in the building next door to me here at UMass.  He says that about 30% of the known bots from North America are already on Bugguide, and that the most difficult species to find are already documented, some probably imaged for the first time ever.  Keep those bots coming!
Eric

Professional Identification forwarded by Eric Eaton
Hi, Daniel:
Here is Jeff Boettner’s response….”C” is for Cuterebra, so it is Cuterebra buccata.
Eric

Awesome,
Thats C. buccata a rabbit bot. I sent a post but I am not in the loop with that group so may take a bit for it to be posted.
Jeff

Letter 4 – Bot Fly

Bot Fly?
June 15, 2010
Hi. I believe I’ve caught a Bot Fly in my house. It buzzes loudly. It’s approximately 3/4″ long. I’m curious!!!
Thanks, Barb
Orange, VA

Bot Fly

Hi Barb,
Your identification of a Bot Fly in the genus Cuterebra is correct.  We must congratulate you on the time and effort you put into trying to identify this unusual creature that has such an interesting life cycle.  We just utilized a similar catch and photograph (and hopefully release) technique with a Flesh Fly found in our own offices.  The best way to remove an insect from the home without handling it directly and without harming it is to use a glass to capture it, and then slipping a postcard under the glass.  The creature may then be photographed and released, or just released.

Letter 5 – Bot Fly

Bot Fly?

Bot Fly

Bot Fly?
Location:  Puyallup, WA
August 24, 2010 12:21 am
After doing research on your site, I’m pretty sure this is a Female Bot Fly. What I don’t know is what type? Rodent, Rabbit, or Squirrel. I have to say after reading about them, I’m fairly grossed out. This one was buzzing around in my livingroom window. After letting her go, she hung around long enough for me to take pictures.
Your site is great! Thanks, bettyluvsduncan

Bot Fly

Dear bettyluvsduncan,
You did a very fine job identifying this unusual fly as a Bot Fly in the family Oestridae.  We believe it is
Cuterebra tenebrosa based on its dark coloration and matching it to images posted to BugGuide.  According to BugGuide:  “Hosts include Neotoma cinerea and N. lepida.”  The genus Neotoma contains Woodrats or Packrats (See link).

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Bot Fly Carnage

This bug is big…
Dear Bugman,
I found this bug on our inside garage window, Buffalo, WY (high desert). I thought the noise must be coming from a large bee or something because of the loudness of the buzzing. I have looked some on the internet, but can’t seem to find a match. I hope some of the pics are helpful. It is an inch long from front to back of the wing. If you look it in the face, it looks like a bulldog.It has a kind of shell over its thorax, similar to a beetle. It’s mainly curiosity to know what it is, as we have only seen one. However, we do have small children and a dog, so if it’s a nasty, I need to know. Thanks!
darla. Buffalo, WY

Hi Darla,
This amazing creature is a Bot Fly or Warble Fly. The larvae of Bot Flies are endoparasites. Most North American species have rodents as host, but tropical species are human parasites. Bot Flies are in the family Oestridae, and New World species are in the subfamily Cuterebrinae. Though there is a Central American species of Bot Fly that will parasitize humans, the North American species are harmless unless you are a squirrel or rabbit.

Letter 2 – Bot Fly

additional bot fly pics
Mon, Apr 13, 2009 at 12:02 PM
I saw that you posted some bot fly pics, but they were a little fuzzy. Here are a few I took that are a little more detailed. Perhaps not the exact same kind of bot fly, but pretty similar. There appear to be three tiny eyes between its two big compound eyes.
Vince
Northern Indiana

Bot Fly
Bot Fly

Hi Vince,
Thanks for sending us your Bot Fly images.  Now people can understand why the Interested Mountain Girl thought it looked like a mutant.

Letter 3 – Rabbit Bot Fly

never seen this one!
August 18, 2009
I was out shooting at Goose Lake Praire in Illinois and came across this red eyed black and grey bumble bee looking bug.Ive never seen one before …any ideas? One friend thought it was a bee fly but I cant find any photos that look like mine?! Also it looks like it maybe laying orange eggs or maybe thats part of the plant?
Denise
Illinois

Bot Fly Ovipositing
Rabbit Bot Fly Ovipositing

Hi Denise,
Someone has been hard at work on BugGuide identifying all the Bot Flies in the genus Cuterebra to the species level.  We do not have the necessary skills to perform that task for you.  Bot Flies are mammalian ectoparasites and they are generally very host specific.  Once we took a better look at your photographs, we realized that you caught this female Bot Fly in the act of ovipositing, or laying eggs on the grass.  We would need to further research this, but we believe the eggs hatch and then the maggots would attach to a passing/grazing host.

Bot Fly
Rabbit Bot Fly ovipositing

Comment from Karl
Daniel:
I think you are right on all points Daniel, except perhaps the ectoparasite part. It does look like a Cuterebra spp. which are opertunistic parasites of small mammals. According to the online Merck Veterinary Clinic (http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/71500.htm): “Adult Cuterebra flies are large and bee-like and do not feed or bite. Females deposit eggs around the openings of animal nests, burrows, along runways of the normal hosts, or on stones or vegetation in these areas. A female fly may deposit 5-15 eggs/site and >2,000 eggs in her lifetime. Animals become infested as they pass through contaminated areas; the eggs hatch in response to heat from a nearby host. In the target host, the larvae enter the body through the mouth or nares during grooming or, less commonly, through open wounds. After penetration, the larvae migrate to various species-specific subcutaneous locations on the body, where they develop and communicate with the air through a breathing pore. After ~30 days, the larvae exit the skin, fall to the soil, and pupate.” Sounds a bit nasty!  K

Hi Denise,
This is a female botfly, Cuterebra buccata which is a rabbit bot. Its host is generally Sylvilagus floridanus (and maybe other species of Sylvilagus in some areas). The larvae are sometimes seen in the neck or shoulder, and/or rump and hip of the rabbit. The red marks in the eyes are only observed in rabbit bots, and your location in IL helps narrow it to a few species. Luckily there is just enough of the white lower face showing in your photo to narrow it to C. buccata. They are not very often seen laying eggs, so nice to catch that on film.
equalrights4parasites

Comment from Eric Eaton
Daniel:
That is so awesome!  I know the guy who is working on Cuterebra, and I forwarded him your message.  His name is Jeff Boettner and he works in the building next door to me here at UMass.  He says that about 30% of the known bots from North America are already on Bugguide, and that the most difficult species to find are already documented, some probably imaged for the first time ever.  Keep those bots coming!
Eric

Professional Identification forwarded by Eric Eaton
Hi, Daniel:
Here is Jeff Boettner’s response….”C” is for Cuterebra, so it is Cuterebra buccata.
Eric

Awesome,
Thats C. buccata a rabbit bot. I sent a post but I am not in the loop with that group so may take a bit for it to be posted.
Jeff

Letter 4 – Bot Fly

Bot Fly?
June 15, 2010
Hi. I believe I’ve caught a Bot Fly in my house. It buzzes loudly. It’s approximately 3/4″ long. I’m curious!!!
Thanks, Barb
Orange, VA

Bot Fly

Hi Barb,
Your identification of a Bot Fly in the genus Cuterebra is correct.  We must congratulate you on the time and effort you put into trying to identify this unusual creature that has such an interesting life cycle.  We just utilized a similar catch and photograph (and hopefully release) technique with a Flesh Fly found in our own offices.  The best way to remove an insect from the home without handling it directly and without harming it is to use a glass to capture it, and then slipping a postcard under the glass.  The creature may then be photographed and released, or just released.

Letter 5 – Bot Fly

Bot Fly?

Bot Fly

Bot Fly?
Location:  Puyallup, WA
August 24, 2010 12:21 am
After doing research on your site, I’m pretty sure this is a Female Bot Fly. What I don’t know is what type? Rodent, Rabbit, or Squirrel. I have to say after reading about them, I’m fairly grossed out. This one was buzzing around in my livingroom window. After letting her go, she hung around long enough for me to take pictures.
Your site is great! Thanks, bettyluvsduncan

Bot Fly

Dear bettyluvsduncan,
You did a very fine job identifying this unusual fly as a Bot Fly in the family Oestridae.  We believe it is
Cuterebra tenebrosa based on its dark coloration and matching it to images posted to BugGuide.  According to BugGuide:  “Hosts include Neotoma cinerea and N. lepida.”  The genus Neotoma contains Woodrats or Packrats (See link).

Authors

  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

    View all posts
  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

    View all posts
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9 Comments. Leave new

  • Mutant? I think it looks like a pug dog.

    Reply
  • equalrights4parasites
    August 18, 2009 5:03 pm

    Hi Denise,
    This is a female botfly, Cuterebra buccata which is a rabbit bot. Its host is generally Sylvilagus floridanus (and maybe other species of Sylvilagus in some areas). The larvae are sometimes seen in the neck or shoulder, and/or rump and hip of the rabbit. The red marks in the eyes are only observed in rabbit bots, and your location in IL helps narrow it to a few species. Luckily there is just enough of the white lower face showing in your photo to narrow it to C. buccata. They are not very often seen laying eggs, so nice to catch that on film.

    Reply
  • Daniel:

    I think you are right on all points Daniel, except perhaps the ectoparasite part. It does look like a Cuterebra spp. which are opertunistic parasites of small mammals. According to the online Merck Veterinary Clinic (http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/71500.htm): “Adult Cuterebra flies are large and bee-like and do not feed or bite. Females deposit eggs around the openings of animal nests, burrows, along runways of the normal hosts, or on stones or vegetation in these areas. A female fly may deposit 5-15 eggs/site and >2,000 eggs in her lifetime. Animals become infested as they pass through contaminated areas; the eggs hatch in response to heat from a nearby host. In the target host, the larvae enter the body through the mouth or nares during grooming or, less commonly, through open wounds. After penetration, the larvae migrate to various species-specific subcutaneous locations on the body, where they develop and communicate with the air through a breathing pore. After ~30 days, the larvae exit the skin, fall to the soil, and pupate.” Sounds a bit nasty! K

    Reply
  • Today 9/26/09 my cat brought me a chipmunk with what appeared to be three Rodent Botfly larva attached. I had never know about the critters. The chipmuck was in shock and lay still as I watched the larva “back out” from the chipmunk’s body. I hope I am able to post the photo.

    Reply
    • Please use the identification form which will allow you to attach images. Please put Bot Fly in the subject line.

      Reply
  • equalrights4parasites
    January 23, 2011 10:41 am

    Hi Barb,
    This is a female Cuterebra fontinella, a botfly which uses white footed mice, Peromyscus leucopus, as the host mammal. It is one of the most abundant bots in the east. Adults are not seen often because they only live for about 10 days as they have no mouth parts so they die when they run out of fat reserves. Glad you had the shot of the rear as the fontinella group has white or yellowish hairs on the rump which help in ID. Great find.
    Jeff Boettner

    Reply
  • equalrights4parasites
    January 23, 2011 11:34 am

    Hi BettyluvsDuncan,
    I am pretty confident this is a female Cuterebra approximata which is a parasite of Peromyscus (mice). The female of this species (like yours) is tricky to seperate from C. tenebrosa from pictures. Best done in the hand. Both species occur in your area, but C. tenebrosa uses Neotoma (woodrats) as a host and is a bit rarer as well. But the space between the eyes in your pic better fits C. approximata. I don’t think this species has showed up on BugGuide.net yet? So you might want to cross post it to BugGuide?
    Thanks for the post. We don’t see this species east of the Mississippi.
    Jeff Boettner

    Reply
  • equalrights4parasites
    January 23, 2011 11:54 am

    Hi Vince,
    This is also a female rabbit bot fly, Cuterebra buccata. As carpwoman wrote, it does look like a pugnose dog. These bots do not have mouth parts so they can’t feed as adults, which makes them look “pug” like. Bots with red in the eyes are rabbit parasites. Your species is common in the east and mostly uses Sylvilagus floridanus as a host, although other species of Sylvilagus have been reported. A very pretty fly!
    Jeff Boettner

    Reply

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