Why Do Stink Bugs Stink?


[♪♩INTRO] If you’ve ever made the mistake of squishing
a stink bug, you know exactly how they earned that name. If you haven’t, might I suggest keeping
it that way? Stink bugs give off an awful smell when they’re
attacked or squashed. It’s a defense mechanism… and a pretty
powerful one. There are several species of stink bugs, which
together make up the family Pentatomidae. But the most common type is the brown marmorated
stink bug, an otherwise banal, penny-sized insect that’s native to Asia, but has invaded
all over the world. Some call them “shield bugs” because of
their distinct trapezoidal shape. The hardened shell of their broad bodies acts
as a defensive armor, protecting them from predators and the elements. But their most recognizable defense is that
unmistakable odor — something like a cross between cilantro and skunk. The smell comes from a waxy liquid that contains
aldehydes, compounds that have a central carbon atom double-bonded to an oxygen and single-bonded
to a hydrogen. They also tend to be very smelly. A common one is formaldehyde, which is used
for preserving tissues. If you’ve ever hung out in the back rooms
of a museum or biology lab, you might be familiar with that particular stench. But aldehyde aromas can also be found in your
kitchen, since they give some foods their smells — including, you guessed it, cilantro. The aldehydes found in stink bugs are contained
in specialized scent glands on the bottom side of the animals’ thorax, or middle body
part. And they’re highly concentrated, so even
a little bit causes a big stink very quickly. Some research suggests these aldehydes also
have antifungal and antibacterial properties, so they may be helping stink bugs fight diseases
at the same time. But as anyone who’s been sprayed by a skunk
can tell you, making a stink is a pretty good defense mechanism. So it’s not surprising that these bugs don’t
seem to have many natural predators. That’s what allowed them to go global—and
become a huge pest. They’re known to eat more than a hundred
types of plants, including valuable crops like apples, corn, and soybeans. In 2010, it was estimated that the mid-Atlantic
states in the US lost about $37 million from damages to apples alone. So finding ways to control their population
is important for agriculture. But they’re not just bugging farmers. When colder weather rolls in, stink bugs look
for a comfy place to over-winter—like your home. When one finds a cozy spot, it releases pheromones
that encourage others to join it. Other than offending your nose, stink bugs
are pretty harmless to humans. But if you don’t want them to snuggle into
your house for the winter, it’s best to keep your windows and doors sealed tight. If some get in anyway, whatever you do, just
don’t squish them unless your nose is prepared! Thanks for asking, and thanks as always to
our patrons on Patreon. If you want to suggest questions like this
for us to tackle, as well as gain access to a suite of awesome rewards, you can head over
to Patreon.com/SciShow. [♪♩OUTRO]

100 thoughts on “Why Do Stink Bugs Stink?”

  1. A lot of people in this comment section are saying they don't smell anything from stink bugs. Is there a possible correlation between people who smell the stink and people who hate cilantro?

  2. I've found that squishing them with a square of paper towel folded over twice, then folding the dead, squished bug into the towel and running it to the bathroom and flushing it is a pretty good way to get rid of them without smelling anything. It's always worked for me.

  3. Oh so what I caught in my apartment was a stink bug. I just put it in the freezer then when it died soften it up with water and the I posed it. Kinda like how they do when collecting bugs. It came out nice, I it touched it to hard and it broke 😑

  4. I currently live in a dorm that is constantly raided by stinkbugs, but despite my incessant smashing of them (because I'm too scared of bugs to be humane and take them outside), I have never once smelled the Stinkbug Stink. I've heard that not being able to smell their stink is one of those genetic things, like the people who hate cilantro or can't smell asparagus pee, but I'm not sure?

  5. One North Queensland species is bright pink and 25 mm long. they fly to lights in sumer and I recently got crashed into and sprayed. As well as the smell I felt localised pain caused by the several ml of liquid.

  6. It's a common belief that stink bugs smell bad, but in most cases the odor is not bad, just strong. I actually like the smell of stink bugs. It's quite subjective when it comes to how well something smells.

  7. About 8 years or so ago we had a major outbreak of stink bugs (central Maryland). Back then, there were few natural defenses against them. Since then, I haven't seen more than one or two per season. I wonder what occurred to reduce their numbers?

  8. found a colony of them in my fireplace they made good little fireworks >:3 (apparently they are slightly explosive if they havent released the odor found out the fun way)

  9. I am 100% sure I've seen these bugs and probably squished some at one point in my life and I don't remember any smell.
    Unless they don't exist here ( I live in Portugal )

  10. "If you've ever hung out in the back rooms of a museum" Like you did, Michael Aranda, during the early episodes of The Brain Scoop when you did all the camerawork and editing? Yep, it still has brains on it…and it also has formaldehyde!

  11. Are they in Britain? I'm English and I'm sure I squished one when I was little, but obviously because I was only young, I could have thought it worse than it actually was (the smell) or imagined it

  12. Can you include a little snippet of something the host said that isn't really in the script, but was funny enough to make the cut? I know Hank does it a lot, I was hoping the others could share their humor as well

  13. I love cilantro ~ you’re wrecking it for me! Thank goodness I have never seen, or smelled, one of these bugs in my life! (Knock on wood ~ and I hope I never do, now!!) I want to keep eating my cilantro!! 🙂

  14. I love these little cuties, got a ton of them in MA. Totally harmless and they walk real goofy. Not fun when they fly right into your face though.

  15. They don't stink… I squished them, drowned them, crushed them with toilet paper between my fingers and more and I don't smell their stench.

  16. Ive NEVER felt a scent from shield bugs. And ive sniffed them up close many times. Ive never squished one though so… maybe they werent stressed enough. But i have no idea how a shield bug is supposed to smell.

  17. I fear them. They give me the heebeegeebees. Raid doesn't work on them. Paranoia is setting in.

  18. "Cilantro and a skunk"…man, I didn't quite have the words for it, but those are as good a pair of words as any.

  19. stink bugs are all over the place here in Pa.
    i catch them in my bare hands ALL the time and throw them outside.
    in more than 20 years i have yet to ever smell anything from them. not once…ever.

  20. Those little guys are a big problem! By 2014 stink bug infestation captured 34 states of America and southern provinces of Canada. They are resistant to the majority of insecticides and it's very hard to get rid of them. Here are some tips on how to prevent stink bug infestation:
    https://pestcontrolhacks.com/get-rid-of-brown-marmorated-stink-bug/

  21. I remember I was playing shoots & latter's I put a stink bug on my sister and when she noticed, she freaked out and danced around.😂

  22. I used to spray stink bugs with Lysol and then crushed them with the closest flat object and then cleaned them up. No stink. Lysol too stronk

  23. wrong, no such thing as mistake or have or not, ts not mistakx or good bad, ceptux, do/can do any no matter what and any can be perfect

  24. I just ate a airhead and it tasted like a stinkbug so I looked up what they taste like and found this, life is cool 🙂

  25. you know that feeling when there is one in your hair, and the stinkbug gets all tangled and decides to stink even though you did nothing but witness.

  26. I remember one time a stink bug fell into my drink. I hadn’t noticed, and took a sip. I told my friends that my drink tasted like a stink bug smelled. Only to find out that the damn thing was swimming around in my wine. I haven’t recovered yet.

  27. Y'all makesre they aint behind your posters either. Couple days ago I found a huge ass colony behind one of my posters… lets just say the room smelled like burnt skunk for a day or two

  28. Humans are cry babies…for instance of this same bug is to be a cure for cancer..it will be wiped out to extinction..

  29. I swear I love fall and winter but then I am reminded that stink bugs exist and they like to seek shelter in my house.

  30. I left my window open over the summer and yes that was stupid and I am now regretting it. They’re LITERALLY EVERYWHERE!! I realized this when I was moving my room around and as I pulled my tapestry down about 15 DROPPED ON ME!!!! Well after about ten minutes of screaming a grabbed the vacuum and started sweeping them up (please don’t do this. It will make your vacuum smell) and I kid you not I swept up close to 50. That was three months ago and I still see a few here and there. I think they’re out for revenge for killing their kin folk cause sometimes I’ll wake up and there will be one or two sitting on my stand looking at me. Waiting. Watching. Hatching a plan as I sleep. Well I got news for you. I ain’t goin down that easy! I have plans of my own…. they won’t even see it coming. Muhaaaahaha

  31. An amazing thing about the stink bug is that its chemical stench permeates plastic immediately . I caught one using a small plastic bag as a glove and my hand stank . I tried 3 times at different times each time using a plastic bag and each time it permeated right through. Amazingly potent stuff .

  32. It's best to just try and be peaceful with your stinky housemates, and only start attacking them if they become a pest. The little guys are harmless, they just don't want to freeze to death outside in the winter. And if they become a pest, you have to find a way to kill them without them producing stink, because stink attracts more stink bugs, so you'd have an even bigger problem to deal with. Sometimes I even keep stinkbugs that have some sort of disability as pets. So far the only one I have kept was one who had a leg webbed to the bottom of its body, I guess it got out of a spiderweb and was trying to get the web off, but then its leg just got stuck on the bottom of its body, so it only had 5 legs to use. I just put the guy in a bowl, and feed him apple slices and stuff, and wait until he feels like he recovered.

  33. Just a wad of TP and envelop the stinker, take back to the toilet and throw it in. Watch as it climbs out of the paper and tries to swim. Forward-backward, it gets nowhere. Now PEE on it, chemical war has begun. Gobs of that smell emit against urine. Game over. Humans win for once. FLUSH!

  34. I hate these bugs. I don't squish them I just grab it with something and flush them down the toilet. Since their stink bugs I'll send them somewhere where it really stinks. The septic tank

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