Monday, November 12, 2012

Tiny, Shiny, Reddish-Brown Beetles - Spider Beetles

spider beetle, shiny, hump-backed, reddish-brown
These tiny beetles are fairly uncommon but because they resemble mites or even bed bugs they get a lot of reaction from homeowners when they are found.
Spider beetles are small (1.5 - 4mm), shiny, hump-backed, reddish-brown beetles that are considered to be minor stored product pests (infest stored foods and natural fabrics). They are usually not a major problem in homes but can damage museum collections of animals and dried insects. These beetles are especially common in older buildings.

On first sight people sometimes mistakenly identify spider beetles as mites or bed bugs. They are of course completely unrelated to either of these critters.

The majority of questions I get about spider beetles come from New York City but these beetles occur in other regions of the country as well. There are at least three species that can be found in homes.

Since spider beetles are general scavengers they can infest a wide variety of organic debris so finding a few beetles is generally not a reason for concern. Cleaning and food source elimination is usually enough to manage the infestation. Insecticides are not needed nor are they very effective in this case.

Identification and control tips for a wide variety of other household pests can be found at our main site LivingWithBugs and DIY pest control supplies, including traps and baits, can be found here.



Michele Cuthbertson said...

We moved to a farm house 2 years ago and not long after my daughter started getting what appeared to be spider bites on her. now, 2 yrs later, with having a exterminator for the past year, she still gets them but now has an infection from it. These spider beetles have been found on glue boards in her room. I can not seem to find answers on if they bite or is it possible that she is allegic to them? Please help if you can or direct me to where I can find those answers! Thanks

Jack DeAngelis, Ph.D. said...

We offer a pest id service at

Naomi Lir said...

I have discovered the exact same beetle in my apartment. They fall out of the air vent in my bathroom occasionally. I do not know where the air vent connects to in terms of my building. There are 11 floors and I'm on the top one. But as far as I can tell, these DO bite. The reason I know is because I looked down at my foot, and saw two bright red circles on my foot. As soon as I looked next to the foot that was bitten, I saw one of these shiny spider beetles. I killed it. There's no way it's another type of bug, as it does not look anything like a bed bug, and it looks like this one TO A TEE. Exactly like it.

Anonymous said...

We live in the Riverdale section of NYC (in the Bronx).
My daughter has bites in the same pattern as bed bugs.
I found no signs of bed bugs but these are what I did find.
Internet research identified the spider looking insect as "Shiny Spider Beetles".
I still can not identify the worm like insect. Perhaps it's the larvae of the spider beetle (but I do not think so).
All internet research claims that Spider Beetles do not bite - but apparently this is not our experience.

SAM CHEN said...

This tiny creature bites , I was sleeping one day and felt a sharp stinging that really hearts on my arm so I hit it thinking it was a bed bug and run to the bathroom when I left my hand off my right arm I was surprise it wasn't a bed bug it was a spider beetle , I be seen them around mostly in the bathroom I was thinking they were harmless until I was bitten by one of the , now I bought a net with tiny holes to close the vent opening as well as the heat opening .

Jennifer Devinney said...

I live in a duplex in Columbus Ohio an have been. Seeing these. I haven't seen a lot but enough to be researching to find out about them. My husband an I have reason to think that they do bite. Because he was laying on our bed an felt something bite him an seen one of these where he was laying. I really need to find out if they do because we are adopting a new born an she will be born with I n the next few weeks. I can't have this happen to him/her, we still dont know which wanted it to be a surprise. Where else can I find research about these tiny little pests

Jack DeAngelis, Ph.D. said...

I'd suggest capturing one and having it identified. Ohio State University has an excellent Entomology Dept. as well as Insect Id Service.

Unknown said...

Is it red and looks like circled beads

Sahar Chinyere said...

Hi Dr. DeAngelis:

Do Spider Beetles bite humans?

Thanks in advance for answering!

Jack DeAngelis, Ph.D. said...

No they don't bite.