Currently viewing the category: "Bot Flies"
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Subject: bug mystery in quebec
Location: my yard, near montreal and quebec city, quebec, canada
July 19, 2015 3:45 pm
hi there bugman. found a bug, couldn’t identify it, we’re curious if you can help us. it was pooping white/transparent goop, head upside down in the grasses of my yard. location: southern quebec, canada.
Signature: s+r

Rodent Bot Fly Ovipositing

Bot Fly Ovipositing

Dear s+r,
You images are a thrilling addition to our archives.  This is a female Bot Fly in the genus
Cuterebra, and she appears to be in the process of laying eggs, the “white/transparent goop” that you observed.  Rodent Bot Flies are parasites of rabbits, mice, squirrels and other rodents.  According to BugGuide:  “Females typically deposit eggs in the burrows and “runs” of rodent or rabbit hosts. A warm body passing by the eggs causes them to hatch almost instantly and the larvae glom onto the host. The larvae are subcutaneous (under the skin) parasites of the host. Their presence is easily detected as a tumor-like bulge, often in the throat or neck or flanks of the host. The larvae breathe by everting the anal spiracles out a hole (so they are oriented head-down inside the host). They feed on the flesh of the host, but only rarely does the host die as a result.”

Rodent Bot Fly Ovipositing

Bot Fly Ovipositing

Jeff Boetner, Bot Fly expert, provides some information.
Hi Daniel,
Nice pics. This is a relative of your mystery FL bot from a week or so ago. But this one we can ID as Cuterebra fontinella fontinella. This is a nice shot of a freshly emerged female. The fontinella bots are known for the white rumps on the last segment of the rear end. This is a huge female, they can lay over 1,000 eggs in their short lives. Most eggs are laid in mouse runways or near burrows. The fluid you saw was likely because the female just emerged from her pupae (in the soil). Bots have no mouth parts or digestive tract so no need to poop. They have to store up all their energy they need as adults, by feeding as a maggot in the mouse host, and this one did a good job of that, judging by her big body size. This one is a specialist on white-footed mice, Peromyscus leucopus. This species is our most common bot, yet not found as often as you would think. I have trapped over 200 mice per hectare*. in our plots in MA, and sometimes 80% will have 1-2 bots, so you would think there would be huge numbers out there. And yet many entomologists I have met, have never seen one in the wild. So consider yourself lucky…(or unlucky if you are a white-footed mouse).
Jeff

*a hectare is approximately 2 1/2 acres.

Thanks a lot for the quick answer, dude/dudette(s)! We weren’t expecting close to this quick of a response. I’ll be sure to bug you again for some more IDs (hohoho).
-Simon

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Subject: Please indentify if able, Thank You
Location: Midwest, Minnesota. United States Of America
July 17, 2015 6:36 am
Sitting, right outside my backdoor. Enjoying a morning smoke before breakfast. This little guy, decides to walk across the tows of my shoe. Down onto a leaf in the grass. Kind of resembles a bumble bee. Only white and black. Instead of yellow, and the eyes shaped different. Which leads to my curiosity, if it may be a different species possibly.
Signature: By the person/ individual who is willing to kindly help answer my question 😉

Bot Fly

Bot Fly

Dear person/individual,
This is a Rodent Bot Fly in the genus
Cuterebra, and members of the genus are often very host specific.  Rodent Bot Flies are external parasites on mice, squirrels and rabbits.

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Subject: Insect ID
Location: Odessa, Florida
June 30, 2015 5:21 pm
Dear Bugman, This morning in my front yard, attached to one of my Iris leaves was this really cool insect that I’ve never seen before. At first I thought it was a bumble bee but realized it wasn’t when I got a closer look. It has characteristics of a fly but also a bee. I hope someone can identify it! I’d love to know what it is. Thank you for your time and effort.
Sincerely,
Signature: Brenda Wickham

Rodent Bot Fly

Rodent Bot Fly

Dear Brenda,
You have encountered some species of Rodent Bot Fly in the genus
Cuterebra.  We believe it is one of the fontinella group identified on BugGuide, which includes the Squirrel Bot Fly, Cuterebra emasculator, and the Mouse Bot Fly, Cuterebra fontinella.    According to Featured Creatures, the Tree Squirrel Bot Fly:  “is an obligate parasite of tree squirrels and chipmunks throughout most of eastern North America. The adult and other life stages are seldom seen; instead, what is usually observed from July through September or October is the outcome of infestation, namely the relatively large, fluid-draining swellings (‘warbles’) in a host’s hide caused by the subcutaneous larvae.”  We are going to copy Jeff Boettner to see if he can provide any additional information as he has assisted us in Bot Fly species identifications in the past.

Jeff Boettner responds
Hi Daniel (and please forward to Brenda),
Whatsthatbug is a good name for this one. This is a bit of a mystery. First off, this is a very freshly emerged bot…likely it had not flown yet and was still developing its color patterns and “hardening up”. That said, this one keys nicely to Cuterebra fontinella grisea which would be great except C. grisea is a northern bot (Canada south to NJ!) and not known from FL??? But the status of grisea is kind of still a confused mess. The general host for these guys is deer mice, P. maniculatus in the north. It is possible there is a very similar bot that is still unknown from FL in Peromyscus gossypinus? I would love to see the dna of bots found in this species of mouse in FL. So not sure what to call this for sure –but you are correct that it is likely a mouse bot in the Cuterebra fontinella group. Absolutely, a fabulous find and could be something very much unknown…Thanks for letting me know about it.
Jeff Boettner
boettner@psis.umass.edu

Thanks for the information Jeff and we will pass it on to Brenda.

Thank you both so much for your help and information! Very informative and interesting! I have not seen this bug again since that morning unfortunately. I have two other pictures of it that I’ll email to you. I tried sending all three pictures initially but they wouldn’t go through.
Thanks again!
Brenda Wickham.

Thanks Brenda,
Additional images would be nice.  You should be able to attach to the reply instead of sending a new form.

Good Morning gentlemen, Here are the two additional pictures of the Bot Fly. I’d love to hear about any additional information you may discover regarding this particular species. We have a very large squirrel population here, so that would be my guess as to the host.
Thank you,
Brenda Wickham.

Rodent Bot Fly

Rodent Bot Fly

Thanks Brenda,
We will await any new information from Jeff, but the head on view might be helpful.

Wow Brenda! and Daniel,
This is a female fly by the space between the eyes. It is also almost for sure a mouse bot and not a squirrel or rabbit bot without going into details and for sure . It is nearly identical to Cuterebra fontinella grisea (which will likely become two species judging by dna). But this one is just enough different in looks (and way out of the known host range for grisea which should be north of NJ and nowhere near FL) that I really don’t know what to call it??? This could be a new subspecies of fontinella bot or possibly a new species?
I would love to try and get down that way in August to look for larvae and figure out the host? Not sure if I could get there this year…but will think about it. Its a really neat find. So glad you got multiple views of it. It is something very close to C. f. grisea, so likely using a southern Peromyscus mouse. I will start studying up on FL mice…
Very cool find. Very exciting find!
Jeff

We are really excited to be able to post this unique find and to have such excellent, expert perspective.

Update:  July 14, 2015
I’m so glad the additional images were helpful! This is exciting!! We’ve been at this home for 6 years now and I’ve never actually seen any mice but plenty of squirrels, so that is surprising.  Please let me know if you do get a chance to visit this area. I’d be glad to have you stop by and look around! Do you think it’s possible that I would ever see this bot again or is it usually just a onetime event?  If there was any chance of spotting it again, my husband was curious as to whether I should attempt to capture it?
Brenda.

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Subject: Bot Fly Larva
Location: North Bay, Ontario, Canada
August 21, 2014 10:25 pm
Hi there,
I am located in North Bay, Ontario, Canada. I have recently found a mouse inside my house walking around pretty slowly. I put gloves on and picked him up to put him outside and when I looked at him I saw a weird brown thing protruding from his side. Upon closer examination I determined it was alive and I recognized it as a bot fly larva that I had read about online a while ago while researching animal parasites. I pulled it out carefully with tweezers, plus about 5 other ones. They were quite large. I have a video of this extraction. I estimate the larger ones were roughly 3cm, maybe slightly larger. Definitely matched the description of rodent bot fly larva. I kept the mouse in a container and fed him until his wounds healed and let him go.
A couple days later (before I let the other mouse go) I was cleaning out and removing a big work tent that was in our backyard that had been used for our house renovations. It was damp, lots of wood scraps etc. I emptied a basket of garbage wood and a mouse emerged from the stuff I was dumping. He was slow and you could actually see two huge bot flies hanging out of him. Very disturbing.
Due to the fact that I have worked extensively in that gross work tent, plus the other mouse was found in our house full of the parasites, some serious questions have come up.
Firstly, how concerned should I be regarding bot fly infections on/in me or my two cats? Is there something I should be looking for on the three of us (obviously a gross black worm thing, but I would prefer to catch it waaaay before that).
Secondly, is this normal??? Are bot flies common this far north? Should I be reporting this, and if so, then to who?
Lastly, how do I avoid coming into contact with the eggs? Are there common types of material they are laid on or environments I could perhaps minimize in order to dissuade them from being laid near my house?
Thank you for your help with this.
Signature: Kate Griese

Bot Fly Larva

Bot Fly Larva

Dear Kate,
Thank you for your thorough and engaging request.  You are correct that this is the larva of a Rodent Bot Fly.  A link from that posting is no longer valid, however we did quote from what might have been the College of Veterinary Medicine at Michigan State University which stated:  “
Cuterebra is a normal bot fly of rodents and rabbits, but can also infect cats, dogs, and man. ”  This online library seems to support that cats can become hosts to Rodent Bot Fly larvae.  Companion Animal Parasite Council indicates:  “Cats and dogs are accidental hosts.”  VCA Animal Hospitals indicates:  “Cats are accidental hosts of Cuterebra larvae. They are most commonly infected when they are hunting rodents or rabbits and encounter the botfly larvae near the entryway to a rodent’s burrow. Most cases of warbles in cats occur around the head and neck.”  BugGuide data on sightings indicates that you are in the normal range for Rodent Bot Flies.  We believe it is highly unlikely that a human will be parasitized by a Rodent Bot Fly.  We will attempt additional research on this when time permits.

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Subject: What bug is this?
Location: Maple Grove, MN
July 26, 2014 4:57 pm
Found in our flower garden today. What is this bug?
Signature: William Huybrecht

Bot Fly

Bot Fly

Hi William,
This is a Rodent Bot Fly in the genus
Cuterebra, and they do not feed as adults.  The larvae are subcutaneous parasites on rodents and rabbits.

What's That Bug? does not endorse extermination

Subject: Black bug
Location: Gunnison, Colorado
July 21, 2014 5:08 pm
I found this bug in my home. I thought it was a bee at first but then with a closer look it seemed to be an oversized fly. I looked up horseflies but the bug I found had widest eyes. What is it?
Signature: Audrey

Bot Fly

Bot Fly

Dear Audrey,
There is enough detail in your images for us to determine that this is a Bot Fly in the genus
Cuterebra, the Rodent Bot Flies, but we haven’t the necessary skills, and we suspect there is not enough image detail for even an expert to determine a species identification.  You can compare your image to this individual from BugGuide that also is identified only to the genus level.  According to BugGuide:  “Females typically deposit eggs in the burrows and “runs” of rodent or rabbit hosts. A warm body passing by the eggs causes them to hatch almost instantly and the larvae glom onto the host. The larvae are subcutaneous (under the skin) parasites of the host. Their presence is easily detected as a tumor-like bulge, often in the throat or neck or flanks of the host. The larvae breathe by everting the anal spiracles out a hole (so they are oriented head-down inside the host). They feed on the flesh of the host, but only rarely does the host die as a result.”

What's That Bug? does not endorse extermination