This one’s a stinker! (Brown Marmorated Stink Bugs)

This week we are talking about the invasive and widely spread brown marmorated stink bug; why there are so many of them and why you don't want them around. 

 

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Music from Lofi Girl with featured artists: HM Surf, Purrple Cat, and Blue Wednesday 

 

Transcript: 

 

Welcome to Episode 64 of Insects for fun! The weekly podcast on all things creepy crawly with a focus on insects. Today we’re going to talk about stink bugs because my god there are tons of them right now. 

 

In the fall when weather is starting to cool down a very smelly bug starts to make more and more of an appearance, but today we’re focusing on a specific stink bug called that the Brown marmorated stink bug. This bug is native to China, Japan, and other Asian countries but made its way into the United States in 1998. The state of introduction was Pennsylvania but this smelly bug can now be found throughout many states both east coast and west. Coincidentally it was also introduced into Europe in 1998, but I believe this came after the American introduction. For the European listeners you guys can find these in Germany, Turkey, Switzerland, Italy, Austria and much more recently the United Kingdom (gasp). They’re going to take over the world I’m sure except for Antarctica because well… who can actually stand to tolerate that wasteland. Now where you live might also have native stink bugs, so how can you tell the difference? The brown marmorated is a marbled deep brown in color. This is actually where the term marmorated comes from, and these ones have white bands on their antennae as well as a black and white stripes along the sides of their abdomen.

 

And yes this is indeed a true bug like all stink bugs and belongs to the family pentatomidae which is in reference to its pentagonal shape. The marmorated stink bug doesn’t only appear in fall though its life cycle begins in spring, but it takes a little while to reach their final form. For example they go through 5 instars or molts and each one takes a week or so to complete. They aren’t anything special to look at either, making them all the more unwanted by most everyone. They’re relatively small too, only reaching about 1.7cm or a little over half an inch, but their smell is incredibly strong, and is often compared with rotting vegetables. I mean if you’ve ever made one angry then I’m sure you know what I’m talking about. But why is it that we only seem to really notice them in the fall if they’re around all summer? These little dudes do not like cold weather, and as a result are actively trying to enter places that can shield them from the cold like your house for example. Or in my case the school that I currently work at because these things are everywhere, and the best part is that my school literally leaves windows open with no screens. They’re straight up asking for stink bugs and then freak out when they enter the school. But this episode isn’t about the dumb things that happen at my school. So now we know these bugs love the indoors when it gets cold, and are really smelly when threatened or scared, but are they bad for us? 

 

Fortunately for you, this stink bug will not bite you, and isn’t harmful to you or your pets! Sure if your dog or cat eats one they might throw up later or get an upset stomach but the bugs are not poisonous or venomous so don’t go rushing them to the vet. Unless something is really wrong, but I haven’t heard of any deathly allergies to stink bugs. I did learn though that people who have an allergy to cockroaches will likely have adverse reactions to the brown marmorated stink bug, and these bugs can release a pheromone to let other stink bugs know they found a good place to hibernate for the winter leading to thousands of stink bugs in your home. One Maryland household had 26,000 individuals which is totally crazy!

 

On the bright side of things, if they do make their way into your home, garage or shed etc, they aren’t going to cause damage by eating your furniture etc. They won’t even reproduce in your home or eat your food. They really just want to get away from the cold, but of course I don’t blame anyone for not wanting them around. And generally you don’t want these bugs around. In fact New Zealand is actively trying to make sure they don’t enter the island and for good reasons! Jamie I’m counting on you (idk if he still listens to this.. Hope he does!) At any rate these stink bugs are generalists feeding on 100s of plants, and when they feed on plants they cause wilting, bruising, and even less fruit production in hardwood trees. They’ll even feed on the fruits themselves causing lots of losses for farmers! They’re an absolute pain to deal with because a single female can lay up to 500 eggs in batches of 20 to 30 under leaves of host plants. It’s also difficult to find them sometimes, especially on grape farms where they can hide in clusters of grapes. They actually affect the taste of wine too if they get poured into the mix, and this is a result of one of the chemicals they release when stressed called E-2-decenal. This compound is responsible for their stinky smell and is also found in cilantro and most of us know how controversial that plant is. 

 

Something else that was more recently discovered about these annoying little guys is that they leave an invisible footprint on the farms they’re found on. For example researchers at Rutgers University found that traces of brown marmorated stink bugs were in the water that farmers were using to wash their produce. One of the farms they found it in didn’t even have a visible infestation, but on the last day of their surveys a juvenile was discovered in a trap. They were wondering if finding traces of the stink bugs with no visual evidence could be a warning that an infestation is coming. 

 

Now if you’re in an area that has these smelly little monsters around you probably want to know how to get rid of them or prevent them from your home. You might even wanna know regardless to prepare yourself for when they do finally show up, and that part of the show starts now. 

 

Your best line of defense starts before you’ve even seen the enemy. Make sure your living situation doesn’t have cracks or crevices leading to the outside. They’re pretty flexible despite their looks and can fit into slits that are around 4mm in height and holes that are 8mm in diameter, and yes those were statistical findings and we can thank the people at Virginia Tech for figuring those out for us. Also try and keep your outdoor lighting to a minimum if you live in an area with stink bugs. They happen to be attracted to lights at night so you’re basically giving them a welcome home sign. Earlier I said they don’t care about your food, and this is generally the case, but if you leave fruit out in bowls then that might also be attracting them so just keep an eye out for anything suspicious. Also if you’re a household that enjoys using firewood and keeps a stack of it around outside, that could also be a prime location for stink bugs to hide. It’s recommended to keep piles of wood like that at least 20ft away from your house and that’s usually a good idea regardless because as we learned in the carpenter bee episode those make good little hotels for bees too. 

 

I’ve got a really weird one now for you. Fragrant Dryer sheets. Apparently stink bugs are not a fan of these so if you wipe down your windows and door screens etc with dryer sheets you can repel up to 80% of unwanted stink bugs. (That’s pretty neat!) 

But some of you might be saying “But I already have them in my home! What do I do now?” 

 

I’m going to share some tips and trips but first a disclaimer. I’m not a professional in pest management. If you have a lot of stink bugs or ANYTHING in your home do yourself a favor and get a professional in there. If you don’t have a serious problem and just want tips to help keep your space free of them then these tips are for you. 

 

1. Flick them into plastic bottles to contain their stench and pheromones 
2. Don’t squash them or use hard pesticides in your home, you’ll likely make the problem worse. 
3. Okay this one is pretty good, get yourself a shot vac and fill the canister with soapy water. Then just go ham and suck all the stink bugs up. It’s not recommended you use a regular vacuum because the smell is incredibly pungent and can stain the lining of a regular vacuum. 

 

We’ve talked a lot about what these stink bugs eat and how we can get rid of them but are there any animals that willingly eat these? The answer is yes! The majority of these are other arthropods though like spiders, and predatory insects, and the life stage at which these are most consumed would be eggs. Katydids, Crickets, Slugs, Ladybugs, even other stink bugs will all happily feed on marmorated stink bug eggs, but there is one predatory that takes the cake by far, and that would be the samurai wasp  Trissolcus japonicus which is native to Japan. This parasitoid wasp is responsible for over 50% of egg mortality in an egg mass, and they also prioritize the brown marmorated stink bug over other bugs. The funny part is it wasn’t introduced purposefully into the states but managed to get here anyway and now people in the U.S. are like dang, can we buy these in bulk? (I’ll take 20! Spongebob quote) It’s also now found in Europe and Chile, and it seems to follow the marmorated stink bugs wherever they go. The best part is that they even overwinter which means that they can survive colder climates! As for purchasing these, they are not widely available like other parasitoids but maybe someday they will be. 

 

That wraps up today’s episode! As always if you enjoy the show please rate it and review if you can as that is the number 1 way to grow our community other than word of mouth. If you want more content or just wat to support the show you can find it at Patreon.com/Insects for Fun 

 

If you have a listener request you can send it to Insectsfordummies@gmail.com and of course be sure to check out the instagram and or fb page for photos and possibly videos. I made a Tiktok account for this which has close to 900 followers now so I’ll probably add videos on IG reels or something as well. There is also the YT channel! 

 

Anyway Thanks for listening and you’ll hear from me again next week.