White cobweb-weaver spider
I was down in the basement last August trying to decide which of the many spiders down there to catch and photograph, when this little lady caught my eye. Where most of them were dark brown to black, she was practically white!
She’s clearly a cobweb-weaver, family Theridiidae – she had a cobweb-style web (a loose, disorganized 3-dimensional mess of threads), and her body shape is typical for cobweb-weavers: somewhat spindly legs,and a bulbous abdomen.
For once, I actually got a picture of her underside, although it did come out a bit blurry:
One thing about light-colored spiders is that it is much easier to see their eyes than in the dark-colored spiders. Hers stand out very well, and you can clearly see all of them. I think she technically has eight eyes, but the ones on the sides (the lateral eyes) have fused so that they look like one big oval-shaped eye instead of two round eyes.
We get to see a bit of fang here, too: she was opening up her chelicerae just a bit and showing them to me. I think she might have been slightly peeved by this point.
I tried to identify this further myself, but I still don’t know enough to interpret the ID keys in the spider guide. So, I went to BugGuide, and Lynette Schimming suggested it was probably in the genus Enoplognatha, which I can certainly go along with. Specifically, I think it is Enoplognatha ovata. Now, those of you who checked that last link are probably saying at this point, “What, are you nuts? Those have huge red stripes on them, they don’t look anything like this one!” This is true, but it turns out that this species doesn’t always have the red stripes. They are highly variable in color, sometimes the stripes are very pronounced, and sometimes they are practically invisible. You can still see them in this specimen, but they are very faint:
The other thing that makes me think this is Enoplognatha ovata, though, is that it is an introduced European species. As soon as I read that, I rolled my eyes and said to myself, “Well, of course it would be.” By and large, I’m finding that the introduced species are very likely to be the most common species around here.
About this time, it may have occurred to you that Black Widow Spiders are also cobweb-weavers, which leads to the obvious question of whether this one is sufficiently venomous to be dangerous to humans. That’s an easy one to answer: No. Their venom is nothing significant, and they are such little spiders anyway (her body is only 8 mm long) that I doubt they could manage much of a nip in the first place.