Currently viewing the category: "Cobweb Spiders"
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Spiders
Location: Masai Mara, Kenya
December 22, 2010 5:01 am
Hi Bugman,
As you mentioned you don’t get many entries from East Africa, here are a few close-ups of the spiders I live with.

Picture 2: A ”False Button” Steatoda capensis. Came to this conclusion after much discussion with others and much searching.

Keep an eye out for more. I’ve got tonnes!
Signature: Zarek

False Button Spider

Dear Zarek,
Thanks for sending an image of a False Button Spider,
Steatoda capensis,  from the family Theridiidae, the same family that includes the highly venomous Widow Spiders.

When I first found this one (Steatoda capensis), I was a little afraid that it was a Brown Button, but I could never get a good view of the underside of its abdomen to look for that red hourglass shape.  I searched and searched online and finally found some good pictures that pretty much exactly matched what I was looking at.  None of the Latrodectus (widow) pictures I found matched.
Steatoda’s sometimes prey on Latrodectus species, though their venom is not considered to be as dangerous to humans as the black or brown widow’s venom.  Some Steatoda do still have relatively potent venom, though, so I’m still not going to be picking it up and fiddling around with it.
Zarek Cockar

I forgot to clarify, while some Steatoda can have slightly dangerous venom in their bite, this particular one, Steatoda capensis, does not.
Just a general note:  A good reference for Southern African arachnids is the African Arachnid Database (AFRAD), put together by Dr. Ansie Dippenaar-Schoeman, a well recognized arachnid expert in SA.  Website: http://www.arc.agric.za/afrad/afradmain.aspx

Update from Zarek
False Button Full Body
Location: Masai Mara, Kenya
December 23, 2010 4:38 am
Hi Daniel,
Here’s a full body photo of the False Button Spider (Steatoda capensis) I sent in earlier.
She was about 3cm long.
There were two that hung around my tent for several days.
Signature: Zarek

False Button Spider

Thanks for the full body view Zarek.  The resemblance to the Widow Spiders in the genus Latrodectus is much more evident in this image.

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Spider Trapping a Baby Black Widow
Location: Southern California
November 4, 2010 1:10 pm
We found this spider in our backyard on the patio trapping a baby black widow. We are thinking it is either a male black widow or a brown widow, but are uncertain. We live in Southern California in the Murrieta/Temecula area. We would love to find out what it is. Thanks!
Signature: Courtney

Black Widow Cannibalism

Hi Courtney,
We are intrigued with your photos of Black Widow cannibalism.  The predator in this photo is an immature female Black Widow that will eventually lose that striped pattern and become a glossy black spider, and the prey is exhibiting the telltale red hourglass of a Black Widow as well.

Black Widow Cannibalism

Thank you so much.  Is Black Widow cannibalism common?  Do all females change like this?  Would it have started out all black like the baby here? I understand if you can’t answer all my questions, but I thought I’d try.
Thanks,
Courtney

Hi Courtney,
We were going to paste the third of your photos into this response so we could better determine the identity of the victim.  We have never seen data on the frequency of Black Widow cannibalism, but the name and alleged reason may be an indication that there is fact in the lore.  With that said, this may be a virgin adolescent female who is still wearing her prepubescent markings.  That may be a suitor that sacrificed his life for the perpetuation of the species.  Black Widows may be able to mate as adolescents and then storing the spermatozoa until it is needed.  Adult females are glossy black and we have not seen documentation of mature females marked otherwise.

What's That Bug? does not endorse extermination

black and red spider
Location: North East USA
October 25, 2010 8:18 pm
Dear Bugman, I beg of your help. I am finding these red and black spiders (i believe) in the house. I live in CT. These bugs are so tiny maybe the size of a grain of rice. The first thing you notice is a little glossy redish black ball. I only find them on the rugs, havent seen them elsewhere. I have two new babies and I am soooooo scared. I dont have a camera to take a picture but I pray you can still help us.
I provided a picture of the closet spider i can find, this resembles the body structure but not the color or size.
Signature: BR

Redback Spider

Dear BR,
You do have some cause for concern if your creatures are the same as the one in the photo, though we have our doubts since you did not provide your own photograph.  This is an immature Black Widow.  Black Widows are one of only a few North American spiders with a dangerously venomous bite, and young children would be more severely affected by a bite than a healthy adult would.  Again, we really doubt that the creatures you have found are Black Widows.

Ed. Note: It has been brought to our attention in a comment that the spider in the photo is most probably not a North American species, but a mature Redback Spider from Australia, which is why the location in which a creature is encountered is often critical information for proper identification.

i cannot thank you enough for you quick response, I dont believe they are either. The structure is similar but they carry a little ball like on them it allmost looks like a bead, if i look at it very close its a maroonish dark red color. We have recently discovered we have carpet beetles and i dont know if this may be related, again we find these spiders on the rug and between the rug and wall. any other advice would kindly be appreciated i will try to get a picture to you as soon as i can, you are all wonderful people for doing this for others. thank you again

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Glossy Red and black spider from Papua highlands
Location:  Tembagapura, Papua, Indonesia
October 2, 2010 10:08 pm
We see these small spiders with a red cephalothorax and upper half of legs and glossy black abdomen and lower half of legs around the house here in the highlands (2500 meters) in Papua, Indonesia. Any ideas what they are?
Signature:  Kevin

Red and Black Spider from Indonesia

Dear Kevin,
This is one awesome looking spider.  We want to GUESS that this might be a Cobweb Spider in the family Theridiidae, the same family that includes such black and red poisonous spiders as the Black Widow from North America and the Red Back Spider from Australia.  Red and Black are codified warning colors in the insect and bug* worlds, and that warning is generally poison.  We hope our readership will come to our rescue with the name of this begloved she-beauty.

* Ed. Note: Bugs are loosely defined as “Thing That Crawl” in Daniel’s new book The Curious World of Bugs.

Spider from Papua

Update
Hi Daniel,
Thanks – I think you steered me in the right direction.  I’m going to guess this is in the Nicodamidae family which was split out of the family Theridiidae (according to what I can find on some Aussie web sites) about 15 years ago.  The Australian Red and Black spider (not to be confused with the Red Back) looks almost identical to mine and is a member of this family.
This one has a body length of 8mm, and from what I can tell looking at pictures would appear to be a female.
Regards,
Kevin

Thanks for writing back Kevin.  As you did not provide a link, we searched and found the family Nicodamidae on the Spiders of Australia website and there were photos of Nicodamus peregrinus, which looks very close to your specimen.  The webpage indicates Nicodamus peregrinus can be found in Eastern Australia, and that “The family Nicodamidae consist of nine genera with 29 descibed species, all living in Australia, one in New Guinea and one in New-Zealand.”  The Esperance Fauna website also devotes nice coverage to the family Nicodamidae.

Sorry for not including the links – yes, those were the sites I found most helpful also.
Cheers,
Kevin

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Black Widows
July 16, 2010
Location:  Tx & Ar
I’m wondering if there is a season for Black Widows, the first pic I’m attaching is from Heartland, TX (SE of Dallas) 7/3/2010 & the second is from Little Rock, AR 7/16/2010, just seems to be that we’re seeing a more than usual. I say that but I’ve never seen one before a couple of weeks ago!
Thanks, Lisa

Black Widow

Hi Lisa,
In warmer climates, Black Widows can be found year round, but sightings will probably be more common during the warmer months when the spiders are more active.  Mature females will probably be most common toward the end of summer and into autumn.  The specimen for Arkansas is not mature.  The coloration of a mature spider does not contain the red markings on the dorsal surface.  Though these sightings were in southern states, we believe both are the Northern Black Widow,
Latrodectus variolus.  Your photo of  the immature specimen matches an image of the Northern Black Widow posted to BugGuide.

Immature Black Widow

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White spider with hour-glass dots on back
March 15, 2010
Found on a dead rabbit, amid the fluff of it’s shed fur. The rabbit had been under an old tin bucket and when I lifted it up, this spider was on the fur.
Colleen
Albuquerque, NM

Immature Black Widow Spider

Hi Colleen,
This is an immature Black Widow, probably a Western Black Widow, Latrodectus hesperus.  The immature spiders often have patterns on the back which become a solid glossy black as the spider matures.

What's That Bug? does not endorse extermination