Killer or Creepy? 5 Japanese Bugs To Avoid This Summer

From killers to just creepers, here are five bugs you might encounter this summer in Japan — and ways to avoid inviting them into your home.

By 8 min read

I remember as a child growing up and seeing something that absolutely terrified me.

No, it wasn’t a horror movie, nor was it the mid-’80s threat of nuclear war. It was a BBC documentary about insects that went into graphic detail about just how many creepy crawlies are living in your house, your bed — and even your body.

Unfortunately, Japan has its own unique assortment of usual suspect insects lurking — and possibly breeding — in your house. Last month’s news of venomous South American fire ants found in Japan is just the latest round of expat bugs to infiltrate the island nation. Although there have been no reports so far of anyone being stung, just this week, biologists warned of the dangers of an infestation, according to a July 9 article in Japan Today.

You’re not yet likely to run into the ants, but there are bugs to be wary of in Japan. It can be hard to tell which insects are safe to pick up and remove and which ones are dangerous to handle. So today, we present some of the worst summer bugs to keep an eye out for and more importantly — how to avoid them.

1) Suzumebachi: the ‘killer hornet’

Japan’s infamous suzumebachi, or “killer hornet,” is one of the more dangerous creatures on this list, as it does kill a dozen or so people every year. However, the actual risk posed by this particular bug needs to be seen in its true context.

The suzumebachi is bigger and has a far more venomous sting than conventional hornets. However, a single attack is unlikely to be fatal to an adult unless you have a wasp/bee sting allergy or you are stung several times in quick succession. The danger posed by suzumebachi comes from the fact that they often live in swarms. You might be more likely to be stung in more rural areas, making it far tougher to seek medical attention if someone does go into anaphylactic shock.

Suzumebachi are rare in urban areas, so unless you live in the countryside near mountains or forests you are unlikely to have them show up in your house. You are most likely to encounter one of these while you are hiking, but some simple steps can help limit your exposure to them.


  • Wear bright colors, as these bugs are attracted to black clothes.
  • Carry antihistamine cream with you.
  • Squeeze the stinger and venom out as quickly as you can if you’re stung. Do not try to suck it out!
  • Apply cream afterward.
  • Go to the hospital as soon as you can, just to be on the safe side.

2) Mukade: what nightmares are made of…

Japanese centipede.

This is a painful one. Unlike the suzumebachi, a mukade (giant centipede) can quite commonly sneak into your house and hide among your bedding, in your shower drain or in your clothes cabinet.

The bite is very painful. Initially, perhaps even more than the sting of the hornet, but it is a lot less dangerous. The bite of the mukade won’t typically require a hospital visit, but it may be a good idea to get some anti-inflammatory medication. In addition to the pain, it can also cause some unpleasant swelling around the bite area. The pain will subside in a day or two. 

For mukade prevention, there are a few methods. First, because they often come into your house through the pipes, be sure to cover all drains when not in use. Additionally, there is a useful powders/sprays, typically labeled with a giant katakana “Mukade” that looks something like this:

Look for this in the local drug/home goods store.

The powder, once poured around the foundation of your house (or even just outside your doors if you’re in an apartment) poisons bugs before they crawl through the cracks of your genkan (entryway area) or balcony. It’s cheap, effective and can be bought at your local drug or home goods store.

3) Cockroaches: where there’s one — there’s more

These are by far the most common household creepy crawlers you will encounter in Japan. They are much bigger and more tenacious than their European and American counterparts.

Contrary to common Western preconceptions, cockroaches in Japan don’t just hang around dirty, unclean or garbage-strewn areas. The hot, humid summer climate in Japan is the perfect breeding ground for these, the most versatile of insects.

First, if you find one in your apartment — don’t panic! If you’re in a big city or newer house, spotting one of them indoors is not necessarily indicative of a nest or an infestation, nor does it call your cleanliness into question. The same might be true for cleanliness in the countryside or in an older house, but here, one generally means there are more.

So, remove the cockroach as quickly as you can. But, keep in mind, they’re quite fast and they can fly. Note that conventional bug sprays aren’t typically very effective on cockroaches. Instead, you’ll need to buy a spray especially targeted at roaches. These bugs are big and scary, but ultimately harmless.

Additionally there are numerous sticky and poisonous traps or other things you can lay down to catch them. The traps are going to be working for you while you’re not in the house, but when you spot a roach, spray is one of the best ways to keep them under control. A way to kill them using the least chemicals is by squeezing dish soap on the cockroach, or if you’re in a pinch, grab any spray bottle of kitchen cleaner if it’s handy and spritz away.

Do not step on or squash a cockroach if you see it. This may release eggs it carries and actually lead to a much bigger problem a day or two down the line.

4) Redback spiders: Black Widow family members

Redback spider

These venomous spiders were unheard of in Japan until about 20 years ago. The first redbacks found in Japan are believed to have come from Australia, with the earliest reported cases of sightings being in Osaka in the mid-1990s.

Redbacks are of the same spider family as the terrifying Black Widow, and their venom is similarly potent. However, fatalities are relatively rare, and despite them having now been confirmed in 22 of Japan’s 47 prefectures, the chances of you running into one or finding it in your home are still rather low.

Japan Today reported that officials maintain a redback spider bite can cause severe headaches, muscular pain and in some cases, death. It’s important to know what to do if you do encounter one.

If you are bitten, you may not immediately feel unwell. The bite itself may well look similar to a mosquito bite: a small, raised, white bump on the skin. What will be different, however, is the intensity of the pain. One victim described it as like “having a nail driven into my wrist.” This initial intense pain is soon replaced by a deep burning sensation around the area.

What is crucial is that you seek medical help as soon as possible. Fatalities from redback bites are extremely rare, but if left untreated it can cause long-term damage.

Get to a hospital as soon as you can and depending on the amount of venom you have absorbed, the doctor may either suggest taking anti-venom and anti-inflammatory medications to alleviate the pain and other symptoms until the effects of the bite wear off.

5) Mosquitoes: ever present, always annoying

No list of Japan’s most persistent pests is complete without a special mention of these horrible little beasties. Mosquitoes are probably best known as conduits for spreading malaria. However, the Japanese variety does not typically carry this virus, that is far more common in Southeast Asia. In Japan, your primary worries should be dengue fever — though again this is very rare — and Japanese encephalitis (JEV).

The last dengue fever outbreak happened in Tokyo’s Yoyogi Park in 2014 and was quickly contained after a total of 162 reported cases. No further cases have been reported since. There are a number of vaccines available to protect against Japanese encephalitis.

Overall, mosquitoes in Japan don’t pose much of a threat to your long-term health but their bites are a serious irritant!

Handy ways to combat these bloodsuckers are wearing indoor insect repellent and using smoke and liquid type repellants. A few other ways are to keep soothing cream handy for when you do get bitten, as well as ensuring your apartment has adequate netting in place. Also, try not to leave any large pools of stagnant water lying around in your bathroom or kitchen sink, as these are like catnip for mosquitoes.

While you might not run any of these creatures at all, hopefully with these simple precautions you can enjoy a bug-free summer here in Japan.

Did you spot a creepy-crawly or winged intruder in your area of Japan and not know what it was? We want to help identify it. Tag your photo with @gaijinpot along with #GaijinPotBugs on Twitter, Instagram or Facebook, and we’ll get to the bottom of it!

  • joao says:

    how much? And alive I presume.

  • Kentaro says:

    One more, the huntsman spider..

  • Christina Tsuchida says:

    Another insect to beware of is the ordinary TICK, because it may carry Lyme disease. (Tick=MADANI; Lyme disease=RAIMU BYOU in Japanese.) This disease is also in Japan now. If walking in woods, it is best to wear long sleeves and slacks with long socks. If bitten, find a surgeon or other way to remove the whole tick (not just the body separate from the head). There may be other things one can do.

  • YAkYAk says:

    I eat Mukade for dinner!

  • anonymous says:

    I’ve been living in the urban area of Fukushima for a year and I have encountered the suzumebachi quite a few times already this year and let me tell you, they are big and sooo menacing-looking! There’s no mistaking the loud buzzing you hear for a little bee…it sounds terrifying!

  • Vv says:

    Mukade are no joke… 🙁



This Week in Japan July 10-16, 2017

Every Monday we serve top picks for this week’s events in Japan. To list your event, contact the editor of GaijinPot.

By 1 min read


Cruise Through Tokyo on a Traditional Dining Boat

Tokyo’s waterways offer stunning views of the city in the summer and the boats that ply them offer dining courses for all occasions — from fireworks to ninjas to wedding receptions.

By 5 min read


Japan Wanderlust: This Week’s Inspiring Travel

Join us on a visual trip to white sandy beaches, massive waterfalls and the geekiest cafe in Western Tokyo.

By 3 min read