Bot flies are a group of parasitic insects that lay their eggs on various mammals, including squirrels.
The tree squirrel bot fly, or Cuterebra emasculator, is a species native to the Americas and can be found in places like Florida.
These parasites can cause harm to their hosts, leading to discomfort, infection, and, in some cases, death.
Knowing how to prevent and treat bot fly infestations in squirrels can help protect these creatures and maintain a balanced ecosystem.
Some ways to address this issue include hygiene, habitat maintenance, and chemical treatments.
It’s important to monitor squirrel populations for signs of infestation and intervene when needed.
Understanding Bot Flies in Squirrels
Bot Fly Life Cycle
Bot flies have a unique life cycle. Adult bot flies do not feed or take in nutrients, and they show a high degree of host specificity1.
Their larvae parasitize rodents like squirrels, and their development depends on the specific host they infect2.
Squirrel Bot Fly Species
The tree squirrel bot fly is one example of a Cuterebra species.
There are around 30 Cuterebra species native to the Americas3. Five of these species are found in Florida2.
Common Hosts
Cuterebra larvae typically parasitize native rodents (e.g., mice, rats, tree squirrels) or lagomorphs (e.g., rabbits, hares)2. The host can influence the development of the bot fly.
- Tree squirrels
- Rats
- Mice
- Rabbits
- Hares
If an animal like a cat consumes one of these hosts, it too, can become infected
Comparison Table: Cuterebra Species & Hosts
| Cuterebra Species | Preferred Hosts |
|---|---|
| C. emasculator | Tree squirrels |
| C. fontinella | Mice, rats |
| C. cuniculi | Rabbits, hares |
Symptoms and Effects of Infestation
Warbles and Skin Lesions
Infestation of squirrels by the bot fly larvae, known as Cuterebra emasculator, can lead to the appearance of warbles, which are bulges formed under the skin.
These warbles often have a small hole in the center for the larva’s breathing tubes to extrude through.
Skin lesions may also occur during infestation, causing hair loss and dark, thickened skin.
Tumors and Lumps
In some cases, the bot fly larvae may cause the formation of tumors or lumps as they parasitize inside the squirrel’s body.
These lumps can be mistaken for other diseases or conditions.
Comparison table between bot fly infestation and other diseases:
| Condition | Appearance | Cause |
|---|---|---|
| Bot fly infestation | Warbles, lumps; sometimes accompanied by skin lesions | Cuterebra emasculator larva |
| Squirrel pox | Skin lesions, pustules, and scabs | Squirrel pox virus |
| Notoedric mange | Hair loss, dry and thickened skin without crust formation | Notoedric mite |
Effects on Squirrel Health
Though bot fly infestations can be unsightly and uncomfortable for squirrels, most healthy adult squirrels can recover from the infestation without long-term effects.
However, in some cases, it may lead to secondary infections, illness, or even death, especially in weaker or younger squirrels.
Identifying and Treating Infested Squirrels
Assessing the Infestation
When assessing a potential bot fly infestation in squirrels, look for signs such as:
- Swelling or lumps on the squirrel’s body
- Restlessness or discomfort
- Hair loss around the affected area
Bot fly infestations are typically caused by the tree squirrel bot fly (Cuterebra emasculator).
The female bot fly lays eggs near the squirrel’s habitat, and the larvae burrow into the squirrel’s skin, causing wounds.
Consulting a Veterinarian or Wildlife Rehabilitator
If you’ve identified a bot fly infestation in a squirrel, it’s essential to consult with a veterinarian or wildlife rehabilitator for advice. They can:
- Assess the severity of the infestation
- Recommend appropriate treatment options
- Provide guidance on preventing future infestations
Treatment Methods
There are several methods for treating bot fly infestations in squirrels. Some common treatment options include:
- Manual removal: The larvae can be carefully extracted from the squirrel’s skin by a professional. However, this can be risky and may potentially harm the animal.
- Medication: In some cases, medication may be prescribed to help the squirrel’s body naturally expel the larvae.
- Supportive care: Providing the squirrel with a safe, clean environment and proper nutrition can help its body recover from the infestation.
It is crucial to remember that treating bot fly infestations should be done by a professional to ensure the safety and well-being of the squirrel.
Prevention and Control
Environmental Modifications
One way to prevent and control bot flies in squirrels is to modify their habitat.
By cleaning up vegetation, like overgrown bushes and tall grass, you can reduce nesting sites for rodents and lagomorphs, which are the main hosts of bot flies.
Some examples of animals that could be hosts include rabbits, hares, chipmunks, and tree squirrels.
Additionally, managing the populations of predators such as foxes, wolves, and deer can naturally help control the number of potential hosts.
Protecting Pets and Other Animals
It’s essential to protect your pets and other domestic animals from bot fly infestations.
For instance, dogs and cats should be kept away from areas with high rodent populations or where bot flies might be prevalent.
Moreover, regularly checking your pets for signs of infestation, such as skin lesions or lumps, can help in early detection and treatment.
In case of infestation, consult your veterinarian for appropriate treatment options.
Human Interaction and Risks
Potential for Human Infestation
Bot flies, such as the tree squirrel bot fly, mainly infest rodents and lagomorphs (rabbits and hares).
There is a low risk of human infestation as bot flies are host-specific, and the species affecting squirrels do not naturally infest humans.
Squirrel Consumption Safety Tips
If you plan to hunt and consume squirrels, consider the following safety tips:
- Inspect for bot fly larvae: Check the squirrel’s skin for signs of infestation, such as bumps or irritated open wounds.
- Skin and clean the animal: Properly skin and clean the squirrel, removing any bot fly larvae found.
- Cook the meat thoroughly: Ensure the meat is cooked completely to prevent possible transmission of pathogens from larvae.
Minimizing Encounters with Infested Squirrels
To reduce the chances of coming across squirrels infested with bot flies, consider the following:
- Check local populations: Be aware of the presence of bot flies and infested squirrels in your region.
- Limit close contact: Avoid directly handling squirrels, especially if you notice signs of infestation.
By following these guidelines, both hunters and individuals can minimize the risks associated with bot fly-infested squirrels.
Remember to practice proper hygiene and safety measures when interacting with wildlife.
Conclusion
Bot flies, particularly the Cuterebra emasculator species, pose a threat to squirrels across the Americas.
While these parasitic insects are host-specific, their infestation can lead to discomfort and potential health risks for the affected squirrels.
Wildlife enthusiasts should be aware of the signs of bot fly infestation and take preventive measures, such as habitat maintenance and monitoring squirrel populations.
If an infestation is suspected, prompt consultation with a veterinarian or wildlife rehabilitator is crucial. By understanding and addressing this issue, we can ensure the well-being of our squirrel populations.
Footnotes
8 Comments. Leave new
I have 3 bot flies that have taken up residence in my picnic table. It started a couple of years ago I noticed them flying around the table & in my garden feeding on the squash pollen. I took pictures as best I could. This year I discovered they had bored a hole in the bottom side of the table. It is made of clear heart redwood & the hole came up from underneath. It was about 1/2″ in dia. & extended abt. 8″ horizontally. 2 of the flies are black & 1 is golden. I have pictures if you can tell me how to send. Dean
The insect you describe does not sound like a Bot Fly, but rather, a Valley Carpenter Bee.
Dear Andersons,
You found a chipmunk botfly, Cuterebra emasculator. The bots name is unfair, they don’t really emasculate their host (as was thought when named). I believe yours is a female, although a bit hard to tell from the pic. It could have been shooting off eggs when hassled. They can lay up to a thousand eggs per female. I would have loved this specimen. I am working on these bots as we speak. In the north these bots use chipmunks mostly as a host, and in the south they use grey squirrels. So these may be two subspecies. I am trying to look at dna to compare northern and southern emasculator specimens. They do buzz like a bee when held, and do look much like a bee, but only have 2 wings-bees 4. Nice detective work, only the rabbit bots have red in the eyes. So good job keying it on your own.
Jeff Boettner
Plant, Soil and Insect Sciences
UMASS-Amherst
Amherst, MA
boettner@psis.umass.edu
Dear ColeDean,
Bugman is correct. Yours are not bots, but carpenter bees. Bots do not have mouth parts and hence they don’t feed as adults, ie they can’t nectar. Bots also do not burrow into wood, but carpenter bees do. Bots do look a lot like them for sure, but bots only have 2 wings.
Jeff Boettner
Horse owners can tell you that botflies do exist in temperate places. We used to see their eggs all over our horses’ legs in the summer. They were little tiny yellow nits and they had to be scraped off with a blade.
Are there bot flies in Massachusetts?
Yes they are found in Massachusetts. Here is the sighting map from BugGuide.
I wonder if you know why the halteres are so big, if they are really halteres, that is. Do they serve a different function in botflies than other flies?