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Friendly Cockroach - Luridiblatta trivittata

Friendly Cockroach - Luridiblatta trivittata
Marin County, California, USA
July 6, 2009
Size: 5 mm
I thought this might have been a German Cockroach, but it doesn't resemble the images of them I found.

Images of this individual: tag all
Friendly Cockroach - Luridiblatta trivittata Friendly Cockroach - Luridiblatta trivittata Friendly Cockroach - Luridiblatta trivittata

2022 update: not sure if it'
2022 update:
not sure if it's Covid, or the drought we have been in, or finally a bird who eats them?
these little guys are no longer around here
haven't seen them in at least two years
forgot all about them until I came across my old files on them
don't exactly miss them... but they were never much of a problem for us

They made it to Oregon.
I've been finding these in and around my home in the Rogue Valley. Has anyone determined if sightings may mean infestation with these?

According to the guide page, this species is probably harmless and not a pest. Indoor specimens have probably gotten "lost" after wandering in from outside, and I imagine they cannot live there for long.

I don't think they've been recorded in Oregon yet. Can you upload a photo to BugGuide?

Increased frequency.
These are seemingly more plentiful than previous years at my home in Josephine County, Oregon. Unlike previous accounts of folks seeing them in the summer, they are appearing more frequently as summer wraps up and the weather gets wetter. I was comfortable believing that they aren’t pests but the more I find them the more I wonder. I seem to find them mainly in my bathroom and kitchen.

three-stripe roach
Still waiting for an agreed-upon common name, these are called the Three-Stripe Roach, The Friendly Cockroach, and Luridiblatta trivittata is their scientific name.
I live in San Rafael, near China Camp State Park. They appeared in my house and yard a little over a decade ago, and seem to have been accidentally imported from somewhere in Southern Europe or Eurasia.
So far they do not seem to be very interested in any of our human foods -- but we do find them near the cat's wet food and kibble all the time, so we infer that is what they like... another contributor said they ate dog kibble.
They are easy enough to kill/crush, but I wish someone had figured-out what best kills them, or what brand of roach trap might be effective -- but I get the impression that they are all over the neighborhood and just wander in... so there's likely no way to kill the background population in the area. They also seem to be spreading at a fast rate -- from which I infer that there are no natural predators to keep them in check? We have plenty of birds, lizards, mice... but while we see more and more of the bugs we are not seeing a subsequent increase in predators. Last winter's rains may have added to their population or food resources... our yard is full of cut-down grass clippings (fire control) and maybe that's what they are primary living in, as we don't have a lot of leaf clutter around our house. (plenty up the hill in the forest, but not many trees around the house)
BTW, that blue stain you see when you crush some is NOT their blood... it's their egg sacs... so crush-away!
BTW2, someone actually has a web site entitled "Culturing Luridiblatta trivittata" where you can learn some additional factoids about them. Why anyone would want to cultivate roaches in a world full of them is beyond me, but that's what I found while researching this bug.
BTW3: BugGuide is a GREAT site! Thanks for all the info.

More info please
I believe I have these visitors in my home. Anyone have any further information to help me? I am very concerned as I have two small children one that is crawling.

Is this the same critter?
Within the last couple of weeks started finding a few of these in the kitchen and outside the front door our home in El Cerrito CA.

They're small (maybe 1/4" long), aren't afraid of the light and they have blue guts when I kill 'em.

Aside from cleaning the heck out the place, sealing up any potential entry points (tough to do for something small) and dusting diatomaceous earth around, any suggestions for getting rid of them?

yep that's the same critter!
I assume diatomaceous earth would work but I agree with you that trying to seal up holes would be quite a challenge. If it's any consolation, they don't really seem to infest homes like other pest roaches. At least this is the case at my apartment, where they are living outside and come wandering in frequently (similar to a house fly or something). According to others online they only show up in the summer and are completely gone during the winter- so it's much better than a German cockroach for instance, (actually from Africa) which sets up a permanent infestation in your home.

My findings are pretty redund
My findings are pretty redundant but I recently moved to Novato, CA and we have a ton of these guys in our apartment but they didn't show up until summer (as others have noted). I also noticed them among the fennel plants by the ferry building in Larkspur, pretty far from any domiciles so as others have stated they seem to be pretty established outdoors and not only in homes.

in sebastopol
lots of these (well, not LOTS) but quite a few here and there in my house in Sebastopol, I have also found them in the chicken coop.

Found indoors, Santa Rosa, Ca
Found indoors, Santa Rosa, California, crawling down a wall and across my entry room floor. Last night I returned from visiting a friend in Fullerton, California. While I don't want to rule out coincidence, I can't ignore the possibility that I brought it home with me. My friend's place wasn't the cleanest. This is my first and only sighting so far. My wife found several bait/trap/kill solutions online. If you own a pool, one available option is to poor a small circle of diatomaceous earth around some bait, basically any kind of food that you may have been leaving on table or counter tops. Diatomaceous earth, D.E. as its known at your local pool supply store, is harmless to human touch (do not inhale) but lethal to this little critter when they lick it off themselves. Not a pool owner, since obtaining even the smallest quantity of D.E. is not practical for this application, try greasing the rim of a glass or jar. Grease will prevent traction to crawl out and since this insect does not fly it will be trapped.

little buggers
Ok. So i finally found these little buggers. Have we learned anymore about these guys? I live in very west Marin Pt. Reyes Marshall area near the coast. Pretty coastal and close to Petaluma but weather out here is entirely different. It is neither Hot nor dry out here in fact its quite the contrary.
We have lots of bugs out here but THIS little guy and members of his family are not too prevalent here on the ranches. Has there been any news about eradicating them?
I see them outside during the day and around the barn at night and in the evenings quite a few of them which is a bit concerning.
We have pest control coming out next week - whom doesnt "believe" cockroaches "live outside" so we will see... They will only be spraying outside... not happy about it, but these guys have to find other accommodation arrangements. Anybody have any updates. I fear they are breeding like cockroaches... By the way - some of them when you squish them have blue blood. No fooling.

Found in Santa Rosa, CA
I started noticing these last month (August), I have only seen 3 or 4 of them in that time though. I live in an apartment so no telling how many my neighbors may have.

Found indoors, Santa Rosa, Ca
Sorry, double post.

also in SF
these guys showed up about 2 or 3 years ago and have really blown up this year. not liking seeing them take to my kitchen and bathroom this way.

Phyllodromica Trivittata in West Marin for over a year
We noticed these bold little buggers over a year ago in our bathroom and kitchen. They are also outside of the house. During the past couple of months there seems to be a significant increase in numbers or maybe just indoor activity. They are now showing up outside at our neighbors barn. If photos are helpful or needed I'll take one the next chance I get (which should be soon!).

Q: We've been calling them German Cockroaches only because until yesterday we didn't know what else they might be. What is their common name?

New Healdsburg Residents
I've lived in Healdsburg, CA since 2002. This week, I started seeing this species for the first time. I have seen several outside, mostly among mulch material and yard debris. Tonight, one scurried in through our kitchen window. Did they come for the wine? 😉

Re: New Healdsburg Residents
I have seen them inside a few times here in Novato, but they never seem to be in large numbers and have never got into food or anything. They seem to just run along the wall.

Common names
The wonderful thing about common names is that it is simply whatever people commonly call it. This species is too new to North America to have acquired a common name as far as I know. It needs one though because the scientific name is hard for many people to use.. Think of something descriptive and start using it! Avoid anything to do with geography, because there are so many mistakes already. (The German cockroach is not from Germany, the American cockroach is not native to the Americas...) If enough people post pictures of this species "naming" it the same common name, then the common name will stick. I look forward to your entry!

My vote...
... would be for the very name that currently graces the title of this post -- "Friendly Cockroach"!

It could only help the PR for this little guy as its kind already inspires so much derision and negativity from people. I sometimes wonder how people might react if when asking what this unwanted critter in their house was, the reply came back, "What you've got there is the Friendly Cockroach!" *GRIN*

Obviously I'm having a bit of fun here, but I kinda' do think that would be a great name. My second-choice would be "Three-lined Cockroach", as most of the specimens seem to have three prominent dark markings on the back. Or, perhaps something that highlighted the fact that even the adults resemble juveniles might also be helpful/fitting. Still working on that one though... The "Forever Young Cockroach", perhaps???

Re: My vote...
I second that vote for "Friendly Cockroach"! Although, I'm a bit biased since I'm the one who coined that term, hahaha. Doing a google image search for that name does show at least one other photo that isn't mine. :D I really just used that as the title for the photos because unlike most cockroaches I've found, this one sat quite contently on the leaf while I was photographing it, whereas most other roaches quickly scurry away.

I've never found these roaches in my house, though I do see them outside fairly frequently. I was planting some shrubs on the hillside next to my house a few days ago, when I found a female with an ootheca rather deep underground (I'd say about 8-10"). I've also seen them on the yard waste bin outside. They don't seem to be very abundant, at least around here.

All in favor - say "Aye"
I'll vote for Friendly Cockroach. I see that the CDFA calls them by a descriptive, yet boring name of Three-lined Cockroach. I think that Friendly Cockroach is just as descriptive. I just wish they weren't *so* friendly!

Critter Name
I just discovered these guys over the summer at my place in Sebastopol. Glad they are not "regular" cockroaches, but I drew the line when I found one swimming in my hot chocolate. I think the "Blue Guts Cockroach" is an appropriate name, but at least the "Friendly Cockroach" sounds positive.

phyllodromica trivittata
Since about the beggining of July I have found these little guys in El Sobrante, CA. both inside my house and in the back yard. They have been found during the day and night. Since I have first spotted one in the house I have had roach traps out, but have not caught one in the traps. I find them randomly on the floor or counter and sink.

I don't recall ever seeing these before the first part of July. They are certainly on the move. We were gone on vacation and came back to find them. I am going to spray the perimeter of the house and any wood piles to help reduce or eradicate them.

Any other controll methods ideas would be appreciated. Thanks

they're in Corte Madera, CA too
we started noticing these guys in our house about two weeks ago... August 2011. Like the others say, they don't seem to be very shy. Don't mind the light..

I've put down roach poison pucks for "small roaches" but not sure if that will work. We've seen them in the kitchen, and bedrooms and a bathroom. We see at least one a day - so there must be a lot..

Any help with controlling these would be appreciated.

Moved from Cockroaches.

Phyllodromica trivittata
This cockroach (which has been in Marin County for several years) was only recently identified - on The photos on were identified by George Beccaloni (The Natural History Museum, London, UK). The species is Phyllodromica (Luridiblatta) trivittata (Serville, 1839) - family Blattelidae.

George said this species: "is known from dry habitats around the Mediterranean. It has been recorded from Morocco; Algeria; Spain; Italy (Sardinia Island); Italy (Sicily); Libya; and Israel. Given that it has not been recorded as being a pest in buildings in those countries (as far as I'm aware) it is unlikely to invade buildings in the USA - although who knows what else it might do!"

Trivittata located in northern coastal Sonoma County-Sea Ranch
Update on this post for geographical tracking. July 2016: Have notice a lot of these are in yard and just this month have begun appearing randomly indoors.

Thanks for the information!
I've been hoping they might eventually get identified. Have they been recorded outside of Marin County? I've never found these little guys in the house, only outside under debris.

Phyllodromica trivittata
Thanks to Daniel Marlos , I now have a name for this somewhat annoying addition to our household.

At our place along the southwestern edge of Petaluma, we have quite a number of these critters, both outside in the yard AND inside the house. So far I have not seen them munching anything, but their numbers must mean they are indeed eating, as well as reproducing a bit too efficiently.

So far they all seem fairly small (~.5 cm), lack wings, and don't avoid light. We have found them walking across bedding and adjacent furniture. I would like to do something to get rid of them, but don't know exactly where to begin. Perhaps better vigilance with the vacuum cleaner for starters.

Phyllodromica trivittata
They're moving north, Marin, Petaluma and now they're in Cotati.

Phyllodromica trivittata
I started seeing them in Santa Rosa in August 2010.

Tiny field roaches
Yes, I’ve also been seeing them in Santa Rosa for years. Some years there are TONS OF THEM out in our little field. A few find their way inside, and yes, as others have noticed, they like the area around our cat food. I haven’t actually seen them *in* the food, though.

I think they’re kinda gross, too, especially if they pop out around company.

Boric acid powder is what I use to get rid of them. It really helps. Needs to be reapplied if it gets wet, or if you vacuum. I like that boric acid isn’t toxic to people or pets.

Do you have a picture?
Mapping the distribution of invasive species is one thing that BugGuide could be very useful. This is both geographic and temporal distribution. If you have photos from a new area or from a new month not represented currently, that would be very useful information to include. If so, please submit photos!

Phyllodromica Trivittata
I noticed two of these in my house recently, and when I got a chance scooped one up for close identification. It matches the photo on this site. It seemed roach-like, but different from the roaches I saw on the east coast growing up. This past weekend I disturbed several while weeding in my back yard. I live in Benicia, Solano County, so apparently they're spreading.

If you could add a photograph, that would be very helpful in documenting the movement of this species- even if the photograph is not clear.

Probably the same?
I'm not sure whether the roaches I found in my mailbox today are the same species, or just a similar-looking juvenile version of a different one, but I'm on Cape Cod, which would be a significant migration for these guys to say the least.
Here's a (huge, sorry) picture of the little miscreant on my hand:

Probably Ectobius
Response to Dawn42

This does not look like the s
This does not look like the same type of cockroach we're talking about in this post. the coloration, shape and size are different.

My apologies, they looked ext
My apologies, they looked extremely similar to my untrained eye. Could you perhaps suggest one of the other species on this site that my picture more closely resembles? I'm trying very hard not to panic about their presence in my house and any additional information would be welcome.

Moved from ID Request.

Phyllodromica Trivittata on the move
I have these little critters hanging out on my front porch. A few made it inside but they seem to enjoy the outdoor life a little more. They've made from the North Bay to the east bay in a short amount of time. This is the first year Ive ever seen them in Vallejo CA. Have they become a pest for anyone yet? So far I'm thinking of leaving them alone.

Another Vallejo sighting
Same here - I just found a few of these guys in my home in Vallejo, 94591. Late September 2011 is the first time I've ever seen this - took me a very long time to identify!

Luridiblatta trivittata
I'm finding them inside our house in San Rafael. Only three of them so far - two in the kitchen and one in the bathroom - all have been at night. Do they just go away on their own or are we in for an infestation? Are there health concerns if they are on cooking/food prep surfaces? How do you get rid of them? They are kind of grossing me out. . . don't want to have to call the landlord, but also don't want to be living with roaches. . .

How to get rid of them from inside the house
I started seeing these in Napa about 5 years ago. They love living under dead leaves and my ground cover. This year, after the end of drought, I am finding them all over my house. I read somewhere that they're not attracted to roach bait, so I've put diatomaceous earth at every door threshold. Is there a better way? I can't stand seeing them in my house!

I have an infestation within
I have an infestation within my house in Benicia. We have seen a total of 10 so far and they seem to just be scavenging near ants which we also are seeing an invasion of. This is all after clearing and acre of brush. It seems that California sightings are too far and few in between that we can't get definitive data on how best to deter or kill them. I feel collection and experimentation by us lay-people should be conducted because it seems the invasion is growing.

Phyllodromica trivittata
I am looking for samples for my entomology class. Are you still seeing these?

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