Currently viewing the category: "Bot Flies"
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Giant Fly
Location: Yakima, WA
November 1, 2010 4:18 pm
Biggest dipteran I’ve ever seen.
Signature: Paul Huffman, President-for-Life, Moclips Surf Club

Bot Fly

Hi Paul,
We strongly believed that you had submitted an image of a Bot Fly in the family Oestridae, but most individuals we have identified in the past are marked with black and white patches similar to the patterns on a Holstein milk cow.  We quickly found a matching photo on BugGuide that is identified as the Bot Fly
Cuterebra tenebrosa, and Natalie McNear from Marin County California who submitted the photo wrote:  “Looking on here it most closely resembles the New World skin bot flies of the subfamily Cuterebrinae, but I don’t see any on here that are all dark with a metallic blue abdomen.”  There is a comment by Jeff Boettner on the posting that indicates:  “I am pretty confident this one is likely Cuterebra tenebrosa. There are a few other species that have all black females, but you have shots from all angles, so likely this is correct. The bot uses Neotoma (wood rats) as a host. … There is a very robust comment dialog on that posting that is well worth the time to read.  The genus information page on BugGuide provides this information on the life cycle of the Bot Flies:  “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. Bot Flies are also known as Warble Flies. These Bot Flies really are quite large and they resemble bumble bees in both appearance and sound.

Bot Fly

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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).

Bot Fly

What's That Bug? does not endorse extermination

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.

Bot Fly

What's That Bug? does not endorse extermination

Human Bot Fly larva pics
April 29, 2010
Hey Bug Guys! I have some pictures of the Human Bot Fly larva that I picked up in Belize. (Perhaps more literally, they picked me…). I’d be happy to send them to you if you would like (and enjoy gross pictures).
Sierra

Hi Sierra,
By all means, please send them.  Please keep the subject line the same and include all relevant information.

Human Bot Fly on Host

June 4, 2010
Hi,
Sorry it took me a while to get back to you.  The first picture is the back of my neck, where the larvae were growing (about 1 month after infection) and the second one is one of the larva next to a ruler (CM scale).  I had a miserable time convincing American doctors that I actually had these insects as parasites– they wanted to treat me for staph infections and paranoia.   I was only able to remove/kill them by covering their air supply in the skin with superglue left on over night.  I hope that anyone who thinks they may also have a bot fly infection finds this page and tries the superglue- nothing else I tried (suggestions from the internet of using meat or petroleum jelly) worked.
Thanks and enjoy!
Sierra Blatter

Human Bot Fly Larva

Hi Sierra,
Thanks so much for providing this wonderful account and accompanying images of an encounter with a Human Bot Fly in Central America.

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worm
December 12, 2009
A friend was cleaning a recently harvested florida whitetail deer and inside the jaws of the deer they found some kind of worms that were about the size of the first 2 joints of a females pinky finger. They were white and had pincher like things on what I’m assuming is the head end of the worm.
Susy
Central Florida

Nasal Bot Fly Maggots in a Deer

Nasal Bot Fly Maggots in a Deer

Hi Susy,
We are quite excited to get your image of Nasal Bot Fly Maggots in a Deer’s head.  According to the Missouri Department of Conservation Website:  “Nasal bot flies (Cephenemyia spp.) are common parasites that infest the nasal passages of deer. They most often are found by taxidermists while preparing heads for mounting, although hunters occasionally notice them.  Adult female flies deposit small larvae in the nostrils of the deer. The larvae enter the nasal passages and pass through several stages of development and growth. They are liberated when the deer sneezes. They then form a pupa and emerge as an adult fly.  Although quite large (up to 1 1/2 inches) and unpleasant looking in the final stages of development, nasal bots cause little harm to the deer and do not infect humans. They also do not affect meat quality.
”  According to BugGuide:  “Eggs hatch inside the female fly and the newly emerged larvae are deposited in the nostrils of a suitable host. These larvae quickly migrate through the nasal passages into the nasopharyngeal (throat) region, preferably in the throat (retropharyngeal) pouches (causing nasopharyngeal myiasis in the host), where they settle and develop. After development is complete, the mature larvae are expelled from the host and pupate in the soil. Adults emerge after 2-3 weeks; since they do not feed, their life span is short and mating quickly ensues to complete the life cycle. 2 generations have been reported from the north, with the duration of each life cycle varying with the season. The winter life cycle can take up to 6 months, while the summer life cycle, half of that time.  Remarks  Usually the larvae do not cause considerable harm to the host other than mild irritation. However in the case of heavy infestations, results can be fatal for the host (death by suffocation), and consequently for the larvae (which, since are true parasites, cannot survive without a living host). Some members of the genus (e.g. C. trompe) are pests in reindeer farms in Europe, causing significant mortality and economic loss.”

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wooly bear hover fly (eristalis flavipes)?
August 20, 2009
Found at 8700′ elevation on the summit of Robinson Peak in Washington’s Pasayten Wilderness
Tvashtar
8700′ Pasayten Wilderness WA

Woolly Bear Hover Fly

Bot Fly

Dear Tvashtar,
We looked on BugGuide, and we believe your identification of a Woolly Bear Hover Fly, Eristalis flavipes, is correct.  The species mimics Bumble Bees in appearance and behavior.

Correction by Eric Eaton
August 29, 2009
Daniel:
… Thanks for the prompt.  I do have a couple other corrections: …
The “woolly bear hover fly” is actually something much more uncommon:  one of the bot flies that afflicts horses or deer or sheep.  I’ll try to get my friend Jeff Boettner to investigate, as he knows that family very well.  Meanwhile, if the person wants to submit the image to Bugguide, that would be great.  There are precious few images anywhere of these insects. …
Eric

What's That Bug? does not endorse extermination