A House Guest

Very often here in Portland, I will have a person animatedly try to explain a kind of 'bug' they've seen in their house. There are key phrases I listen for: "It was really big." (giant house spider) "It was black and kinda nasty" (european rove beetle called a devil's coach horse) or "It has these stripe-y long horns." (banded alder borer) But if I hear about something fast that moves creepy with lots of legs that is unlike anything they've ever seen before, then I KNOW it's a house centipede. I'd not seen one in my current house, until a few weeks ago. I was sitting at my kitchen table, chatting with a friend when she reached down to get bag and jumped a bit. I looked down and saw a small house centipede. I immediately swooped down and grabbed it (a feat in itself- they are fast!) and looked around frantically for something to put it in. I knew I wanted to keep it alive until I could photograph it, so I put it into a tupperware filled with soil that we keep our isopods in.


House centipedes have long, thin highly bent legs. Since they are centipedes there is one pair of legs per body segment (as opposed to two pairs on each segment of millipedes) -however these are so fast and the legs are so close together you can't really tell when they are moving.

During the photoshoot, it was very difficult to get a still shot. I put the animal in the freezer for a bit to slow it down but the minute the lid of the tupperware came off and the light/shadow of the microscope or camera hit it, the thing went running. I wish I had the whole experience on video. It would run up the scope onto my arm, I was hopping around trying to not to crush it underfoot when it ran off the table. Hilarious.

*NOTE: for the microscope shots, I used the Microfi with the iPad. Since the lights get very close to the subject they cause a lot of glare and reflection off of the exoskeleton. I reduced the intensity of the highlights on the following images. 


House centipedes are predators! Check out those compound eyes! They hunt all sorts of smaller arthropods, from roaches and silverfish to beetle larvae, bed bugs and spiders. They are great little pest controllers. Don't kill them! They are harmless to humans. (Other centipedes can have very potent venom. I don't recommend killing them- but be wary.)


This anterior shot looking toward the 'face' of the centipede reveals the forcipules. These are the first pair of legs that are modified into venom injecting fangs. Do you see the sharp, needle-like appendage under the left 'chin' of the chilopod? That is the left forcipule! Centipedes are venomous NOT poisonous. Venom is a substance that is injected into prey in order to immobilize and pre-digest it. House centipedes are too small and their forcipules are too weak to really sting us.


Looking up close at the legs, I was amazed at the spines and spurs present! These are barbed little creatures. It's incredible to me the they don't stick themselves as they walk so quickly. Those plates on the top of the animal are called dorsal tergites. They are basically plates of armor (exoskeleton) that cover the top of the body.


I was very happy with this shot. It shows the same dorsal tergites as the previous one, but I think the light is a little better. Also it shows the last segment which is called the telson. Not all arthropods have a telson, but chelicerates- like spiders and scorpions and horseshoe crabs- crustaceans and myriapods (many-leggeds like centipedes and millipedes) have them. For example, in scorpions the telson is the tail which bears the stinger. The telson on a centipede is simply the last segment.

This was a fun post to write and photograph. I let the little house centipede go (in the house!) and thanked it for its service.