Our Better Nature: Assassins and Hunters in the Shadows

Dust-bunnies are those little clumps of dust and lint that mysteriously form beneath beds, couches, and appliances. Maybe they’re called that because they seem to reproduce as fast as rabbits. But no one who uses the dust-bunny moniker thinks the fuzz-balls under their fridge are really alive.

And yet, throughout the eastern half of the country and parts of the Northwest, lots of healthy, lucid folks report seeing tufts of lint emerge from nooks and crannies and scuttle across their floors at night. I imagine this could pose a dilemma: On one hand, you want the critters gone from the house. At the same time, you don’t want a friend or colleague to get the wrong idea if you tell them dust bunnies in your house come to life after dark. If they give you the hairy eyeball and back away slowly, come back the next day with a video.

It’s small consolation that what appears to be living lint is called a masked hunter, a type of assassin bug. Not to worry, though – they neither hunt nor assassinate people. Native to Europe and Africa, masked hunters have spread across much of the U.S. and southern Canada.

These fierce predators of insects and other arthropods get their name from a curious habit of coating, or masking, themselves with dirt and dust as a form of camouflage. Like all members of the order Hemiptera, they have a sharp, stout, beak-like mouthpart called a rostrum, which they use to stab their prey and inject it with enzymes to liquefy its innards. Even prey much larger than themselves are hunted down. The rostrum also serves as a straw for when a masked hunter comes back to scene of its crime to slurp the yummy bug-milkshake from inside its victim, leaving an empty skin (I hope you weren’t just about to eat lunch).

Adult masked hunters are shiny, black, beetle-like insects measuring about three-quarters of an inch long, but in their prolonged “childhood,” they are neither dark nor shiny. During their several immature, or nymph, life-stages, masked hunters are covered in tiny Velcro-like hairs, to which they intentionally stick dust and dirt. They do a good camo job, and can look for all the world like animated lint-blobs. Thus disguised, they can sneak up on prey more easily. It’s like when the cartoon character Wile E. Coyote uses a “mobile shrubbery” trope, covering himself with branches to try (in vain, of course) to grab that Road Runner.

Masked hunters are more successful at hunting than cartoon coyotes. With a broad menu, they dine on any kind of invertebrate they can impale with their rostrum. Like spiders, they’ll clear your home of unwanted critters such as those rather unsettling house centipedes. That sounds like good news, and indeed it might be. But let’s just say masked hunters could be a mixed blessing.

Normally, they like to be outside where most of their prey are, and generally are found in small numbers, if at all, in homes. If you see one or two of the wee assassins scooting around your house, chalk it up as a curiosity that’s more than likely an asset to your indoor ecosystem. On the other hand, if you have lots of dust bunnies getting underfoot, it means that masked hunters are finding plenty of critters to eat, and that’s usually bad news.

For example, masked hunters love to munch bed bugs, their favorite – and everyone’s least favorite – bedfellows. If a platoon of masked hunters marches in, look for signs of bed bugs, like staining between mattress and box springs, as well as along the mattress seams and piping. Also, be aware that unexplained skin rashes could be the result of bed bugs. For help addressing a bed bug infestation, contact your local Health Department or a licensed exterminator. Don’t panic, but you should get professional advice.

If bed bugs aren’t the problem, breathe a big sigh of relief. Then, check for other possible infestations. Larder beetles are drawn to high-protein foods, and can proliferate if they have access to cheese, or even a dead mouse nearby. Masked hunters also could be after so-called pantry pests, such as the larvae of the Indian meal moth, which infest grain-based products like flour, rice, oats, and crackers.

Although masked hunters are decidedly non-aggressive, they do on occasion bite people. This can happen inadvertently if you come in contact with one while house cleaning. Most dust-bunnies don’t object if you pick them up, but masked hunters, which can be pretty convincing as dust-motes, get cranky if you handle them. Their bite can cause painful swelling that may last up to a week. Fortunately, given their small scale compared to us, we are not in any danger of turning to jelly inside and becoming their banquet.

If by chance you someday find yourself chatting with a coworker at the office about these fascinating bugs, be discrete, lest your boss hear you describe how the masked hunters lurking under your bed come out at night to assassinate. Not everyone pauses to get the full story before jumping to conclusions.