Retrospectacle: A Neuroscience Blog

At I came across a fantasticly irreverent article about the five most horrifying insects in nature, including the bullet ant, the Japanese giant hornet, and of course, the botfly.

There are dozens of varieties of Bot Fly, they’re each highly adapted to target a specific animal, they have delightfully descriptive names like Horse Stomach Bot Fly, Sheep Nose Bot Fly and, hey, guess what. One of them is called Human Bot Fly.

And since botflies can become lodged into any part of the body, it is not unheard of for them to make their way into the human brain and, well, *feed.* Behold:

i-9f84773b2750a295d818d66c2e4b47b3-botfly brain.jpg

The human botfly is found only in Central and South America, and it lays its eggs on a mosquito (or other biting insect). When the mosquito bites a person, the eggs fall onto the skin and are hatched by the warmth of the body. The larvae burrow into the skin and then travel throughout the body–and can move across the blood-brain barrier, and cause meningitis and death after growing inside the brain, eating and destroying it.

Hat tip Aaron.


  1. #1 Russell
    January 26, 2008

    Nay, the most horrifying bug is the humble mosquito, which cannot be avoided by anyone who works or plays outdoors, and has killed more people than any other insect, by virtue of the various beasties it carries, such as the plasmodiums that cause malaria, and the viruses that cause dengue and yellow fever. And the occasional bot fly egg.

  2. #2 PhysioProf
    January 26, 2008

    I am not generally squeamish, but that brain picture is so horrifying I’m going to have the heebie-jeebies for a fucking week!

  3. #3 Tony P
    January 26, 2008

    That’s what makes me laugh about mosquito eradication programs. They’re just an infinitesimal drop in the bucket. One thing that does knock down mosquito populations is drought which most of the eastern seaboard of the U.S. has been under for the past few years.

  4. #4 Punditus Maximus
    January 26, 2008

    That picture is the most horrible thing ever. Thank you so much for showing it to me.

  5. #5 Mike Haubrich, FCD
    January 27, 2008

    Thanks, now I have a new desktop background image!

  6. #6 cfrost
    January 27, 2008

    At this point I might ponder divine beneficence, but I’m not thinking too clearly, what with the grubs eating my brain and all.

  7. #7 Murgadroid
    January 27, 2008

    I had an encounter with a bot fly whilst living in Brazil in the early 80s. I don’t know where or how it entered my body. But the larva ended in the head of a very delicate and sensitive part of my anatomy!

  8. #8 Lars Dietz
    January 27, 2008

    “The Evolution of the Insects” by Grimaldi & Engel mentions a scientist named Dunn, who published a paper on bot flies in 1930. He exposed himself naked in the jungle of Panama to get stung by mosquitoes, and then protocolled the growth of botfly larvae under his skin and his body’s reactions to them.

  9. #9 Rick Sparks
    January 27, 2008

    Now I want to remake “Pink Floyd: The Wall” with photo-realistic worms eating photo-realistic brains.

  10. #10 Dave Larkin
    January 27, 2008

    soooo… let me get this straight… you are siting as your source for information…. i read that article as well and i’m pretty certain they made their facts up as they usually do as a JOOOKE. Didn’t some of the stats seem a bit odd to you?

  11. #11 Sarah
    January 27, 2008

    ok that was grose! but still interesting, can you imagine having that in your brain?
    idk thats just the coolest and grosest thing i’ve ever heard of and seen.


  12. #12 Tom Renbarger
    January 27, 2008

    I, for one, welcome our new insect overlords.

    (Somebody had to say it, assuming it hasn’t already been said in the original article’s comments.)

  13. #13 Jeff Garofalo
    January 27, 2008

    I had a prof in college who used to carry a botfly maggot that was removed from his wrist years ago in a jar with him most places. I’m surprised the human variety get so big, you would think that the likelihood of their removal would be large enough to constitute selective pressure.

  14. #14 Baratos
    January 27, 2008

    Dave Larkin: No, all these things are real. Those ants in particular are the most horrifying things I have ever seen. Both Richard Dawkins and one baboon researcher I know were terrified of the things as children. They will actually invade villages in Africa, and while the locals can outrun the swarm, the insects will steal alot of the food. Many people there have a mixed view of the ants, because they also butcher all the vermin near the hive.

    Also, the Japanese acid-spraying wasps of doom even frighten exterminators. I understand now why the Japanese are OK with squeezing themselves into cities–because the countryside is full of BLOODTHRISTY ACID HORNETS.

  15. #15 Mason
    January 27, 2008

    I had an encounter with a bot fly whilst living in Brazil in the early 80s. I don’t know where or how it entered my body. But the larva ended in the head of a very delicate and sensitive part of my anatomy!
    Between that picture and this post, I’m sleeping with the lights on from now on.

  16. #16 Indy
    January 28, 2008

    there arn’t any human-fond species in the US (that I know of)-

    but one of the labs in my building was doing a study on DNA adducts in mouse livers/kidneys from a nearby superfund site- they’d go out, catch a bunch of wild mice, bring them back, whack n’ dissect. The fellow grad student who did the wacking liked having others around while he worked, so he invited me up one day. He had a small jar with a bunch of what looked like mulberries floating in preservative- I made the mistake of asking.

    Botflies adults are the really shiny blue or green metallic ones that are immediately attracted to shit or dead things. They lay their eggs in there, the larvae crawl out into surrounding grasses and attempt to get themselves onto any host they can find- usually small rodents- crawl in through the nasal passages, munch their way down to the genitals, and pupate. Basically, the mulberry sized things were pre-emergent, and had been living just under the skin of the tail end of the poor mice. For a human, it would have been like living with a football-sized mass in your tender vittles.

    He had some papers he’d dug up discussing their life cycle and identifying traits, which I totally declined to read.

  17. #17 Jerzy
    January 28, 2008

    Insect which doesn’t need to breathe! Zoological sensation of century!

    Checked urban legends page? 😉

  18. #18 Shelley Batts
    January 28, 2008

    Checked urban legends page? 😉

    Rossi MA, Zucoloto S. Fatal cerebral myiasis caused by the tropical warble fly, Dermatobia hominis. Am J Trop Med Hyg. 1973 Mar;22(2):267-9.

  19. #19 Shelley Batts
    January 28, 2008

    And the botfly has specialized respiration, see:

    Burmester T, Hankeln T. The respiratory proteins of insects.J Insect Physiol. 2007 Apr;53(4):285-94. Epub 2007 Jan 10.

    For a long time, respiratory proteins have been considered unnecessary in most insects because the tracheal system was thought to be sufficient for oxygen supply. Only a few species that survive under hypoxic conditions were known exceptions. However, recently it has become evident that (1) intracellular hemoglobins belong to the standard repertoire of insects and (2) that hemocyanin is present in many “lower” insects. Intracellular hemoglobins have been identified in Drosophila, Anopheles, Apis and many other insects. In all investigated species, hemoglobin is mainly expressed in the fat body and the tracheal system. The major Drosophila hemoglobin binds oxygen with high affinity. This hemoglobin type possibly functions as a buffer system for oxygen supply at low partial pressures and/or for the protection from an excess of oxygen. Similar hemoglobins, present in much higher concentrations, store oxygen in specialized tracheal organs of the botfly and some backswimmers. The extracellular hemoglobins in the hemolymph of chironomid midges are evolutionary derivatives of the intracellular insect hemoglobins, which emerged in response to the hypoxic environment of the larvae. In addition, several hemoglobin variants of unknown functions have been discovered in insect genomes. Hemocyanins transport oxygen in the hemolymph of stoneflies, but also in the Entognatha and most hemimetabolan taxa. Apparently, hemocyanin has been lost in Holometabola. At present, no physiological or morphological character is known that could explain the presence or loss of hemocyanins in distinct taxa. Nevertheless, the occurrence of respiratory proteins in insects adds further complexity to our view on insect respiration.

  20. #20 JasonE
    January 28, 2008

    Wow, not what I needed to see before going on my honeymoon in Costa Rica on Saturday. My boss once described in detail a botfly removed from his friend’s back while in Costa Rica, so I was leery already, but jeesh, that picture is nasty.

  21. #21 Fabio Olmos
    January 28, 2008

    Botflies are a fact of life for biologists in fieldwork in tropical America and the occasional souveni a tourist takes home. A Bitish friend of mine has taken new close friends home twice. One trick to take a larvae from your flesh (if you recognize you have one. Most doctors don’t)is to cover the area with silvertape. In due time the critter will be glued there. No need to cut yourself open. Has worked with me.

  22. #22 October Mermaid
    January 29, 2008

    I saw that stupid article yesterday and words can’t even describe the kind of horror it caused in me! These things are terrifying.


  23. #23 Aaron
    January 31, 2008

    The kids in the neuroscience office wanted me to take it down, so I moved it a bit. The caption was what moved me the most:

    “Botflies in your brain…Eating your thoughts…”

    So poetic. It could almost be the tagline to a blog I could be writing in all the time I wish I had…


  24. #24 Anglique
    March 28, 2009

    The same as everyone else… GROSS!!!!!

  25. #25 Carbon
    May 18, 2009

    This looks fake.Because botfly larvae always stay on the surface of the skin in order to get air.Unless this guy had a hole in his skull.

  26. #26 Joe
    September 8, 2009

    Well yeah Botfly larva are gross but not that dangerous, if you do get one in your skin taking it out will indeed hurt, but the do not travel acroos your body the just feed on what is there around them. The closest they get to the brain would be on your scalp and the only way a blot fly could grow there is if it were able to chew through your skull which it cannot do.

  27. #27 CLARK KENT
    October 13, 2009


  28. #28 halie
    October 17, 2009

    omg well there goes your precious memories becuase a stupid maggot ate it

  29. #29 Jack Ryan
    March 8, 2010

    I’m a neuroscience major, so I’ve seen lots of brain. This is the only one that has ever freaked me out.

  30. #30 Steve Rudman
    April 19, 2010

    Thank you all for your very interesting thread on the human bot fly. These contains more information on bot fly larva than I care to know. I am my second month of a tour of Costa Rica, and I have already had an encounter with the larva of about 60 chiggers.

  31. #31 Steve Rudman
    April 19, 2010

    Thank you all for your very interesting thread on the human bot fly. These contains more information on bot fly larva than I care to know. I am my second month of a tour of Costa Rica, and I have already had an encounter with the larva of about 60 chiggers.

  32. #32 Roy
    April 20, 2010

    How can a bot fly breathe if it’s under your skull? Unless your skull is as thin as your skin…

  33. #33 Roy
    April 20, 2010

    How can a bot fly breathe if it’s in your skull? Unless your skull is as flimsy as your skin…

  34. #34 popz
    April 22, 2011

    It comes 1st. but has any1 heard of the filarial worm???

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