The freaky biology of the centipedes that have invaded my apartment

By Madeline McCurry-Schmidt

When I walk to the bathroom in the middle of the night, I do not want to see this: skittering across the hallway carpet. Yet there it was, a few nights ago, in all its freaky glory. This animal is commonly called a house centipede (Scutigera coleoptrata), and despite my patented lack-of-squeamishness, I hate the thing. It’s like a spider on steroids.

I never saw house centipedes when I lived in California. Apparently, they’re more of a Midwest and Southern thing. Because they can’t close the little holes (called spiracles) in their exoskeletons, they stick to more humid climates so they don’t dry out. They also seem to really like my apartment. Ug!

As they say: know your enemy. So here’s what I’ve learned about house centipedes.

Fact 1: They bleed purple. Squish one of these guys and it leaves a bright purple streak. Purple isn’t really a scary color, it’s just freaky because it’s unexpected.

But it turns out that purple blood isn’t really that unusual. In centipedes and many other arthropods, the blood-like liquid is called hemolymph. Hemolymph is often a grey or greenish. It contains a a protein called hemocyanin, which turns blue when it reacts to oxygen. Hemolymph can also change colors depending on an animal’s diet. Of the California coast, purple hemolymph can be found in sea slugs that eat certain algae. 

I can’t find solid information on why house centipedes bleed purple, but multiple studies show changes in hemolymph colors depending on proteins in the hemolymph. A study of several species of butterfly larvae showed that their greenish blood depends on a combination of yellow and blue proteins.

Fact 2: They can have up to 30 legs. Mature house centipedes have 15 pairs of legs. They start out with 4 pairs of legs, but they increase to 15 pairs as they moult. Not only do they have a lot of legs, but their legs have evolved to make them extra freaky. In the picture shown above, you can see how the back legs are longer than the front ones. The millepede’s back legs have actually evolved to look like antennae, which confuses predators.

Fact 3: They live a long time. House centipedes can live from three to seven years. That means the big ol’ centipede in my hallway has definitely lived in my apartment longer than I have…

…which makes me the intruder.

To be fair, house centipedes are harmless to humans. They actually prey on other arthropods that are household pests. The centipedes in my apartment are hunting insects and spiders. Even though they kill their prey with venom, house centipedes won’t hurt me, so maybe I shouldn’t be so quick to squish them.

And there’s another reason to sympathize with house centipedes.

Fact 4: Reproduction is no fun. The most intimate moment between male and female house centipedes is when they touch antennae. They do this before reproduction to pick up smells from their partners. After the customary antennae-sniffing, the male leaves his sperm on the ground and the female uses it to fertize her eggs.

But then there’s the fact they can lay up to 150 eggs at a time. So maybe I can squish a couple and not feel too bad.

About Madeline McCurry-Schmidt

I'm a science writer specializing in biological sciences and animal behavior.
This entry was posted in Anthropods, Notes from Madeline and tagged , , , , , . Bookmark the permalink.

12 Responses to The freaky biology of the centipedes that have invaded my apartment

  1. R. E. M. says:

    Ugh. Ugh. Ugh. Ugh. Ugh. This changes everything.

  2. Mary Bates says:

    These things give me the heebie-jeebies like no other. I think I have to shower after seeing that photo.

  3. dccampfin says:

    Most interesting about this is life span. Madeline, in your spare time, could you do a piece comparing life spans of insects. I always assume most of these would last at most one breeding season or two.

  4. I used to call these monstrosities ‘Eyelash Bugs’ and if I can’t stand spiders, this thing takes the cake for “too-many-legs-aphobia”. I was working in the CRAWLSPACE of some little old frame shack I lived in years ago and looked up to see the mother of all these *things* inches above my face, just *there*, respiring and regarding me with what seemed to be eyes on its legs. I’ve never lived in a house with a crawlspace since then. Ever.

  5. Creepiest thing about these, in my opinion (and yes, we do get them in houses here in close-to-Toronto), is how the legs keep twitching after you squash them. Eeek.

    That, and how blazingly fast they can run. All those legs, I guess.

  6. Tharsis says:

    I actually really admire these creatures. Ugly spiders, slugs, scorpions, and other living things that are difficult to love have me by the heartstrings, as sick as that might sound. A single house centipede can eliminate brown recluses and other very pernicious pests. I’ve had friends who’ve suffered brown recluse bites and they no longer kill house centipedes–despite their fear. I’ve caught house centipedes before, bare handed and 3″ long. I held them by their back leg while I examined them. At no point did they attempt to bite me, duly noting the massive jaws that are plainly visible. These creatures have a bad rap, and can be saviors of households inhabited by poisonous spiders.

  7. Donna says:

    Mine like to eat M&Ms

  8. Chelsea wood says:

    Omg me and my mom use to find these things in out apartment to we couldn’t figure out what they were so we always killed them.

  9. Pingback: My Soon-To-Be-Former Roommate Ramon, the House Centipede | Tales From A Wandering Albatross

  10. Jake says:

    Freaky things.. Never liked them, but i now have a slightly different enemy in my house. I have no idea what kind of centipede it is. Very small, worm like and long. With what seems like hundreds of legs. They are brownish black. Can’t figure out what they are? Has anyone seen this, or knows what they are?? How to get rid of them? Anything would be nice lol.

    • TSG says:

      If it’s small, thin and black with lots of little transparent legs and has the habit of coiling around itself it would be a millipede. It could also be another variety of centipede. Be careful with centipedes … quite a few of them can make you quite ill with their bite. Millipedes on the other hand just stink when you squash them and are completely non-threatening.

      Oh, and to think that some species of centipede, such as ones found in New Guinea and other jungles can get up to 30cm! (12 inches for everyone in the States, heh)

  11. BETH says:

    these things are so nasty looking,and they feel even worse. I awoke to one crawling on me in bed the other night.If I find it “I WILL KILL IT. Crawling on my floor is one thing, crawling on me is quite another

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