Filmy Dome Spiders Mating: Neriene radiata

Subject: Unknown spiders-Male/Female
Location: Southwest, MI, USA
October 18, 2013 4:45 pm
Had seen this black and yellow spider hanging out in my marigold patch. Thought it was an Orchard Orbweaver at first until I saw my photos on my computer. Then a few days later I saw another smaller spider along with the black and yellow striped one (it wasn’t moving) At first I thought the bigger one was dead and the smaller one was in the process of liquifying its dinner. Then I thought maybe this was a male and they were mating. The next day I checked on the same web and the two were still there and I took the second picture. I also took a video when I thought they might be copulating. It was most interesting. Every 20-30 seconds and amber fluid drop would appear between them and then disappear as if reabsorbed or eaten. Can you tell what these spiders are and what they were up to?
Signature: d. k. dodge

Dear D.K. Dodge,
We don’t recognize your spiders, but based on the tangled web, we are guessing they might be Cobweb Spiders in the family Theridiidae.  We searched through BugGuide, and your spiders bear a slight resemblance to this pair of Phylloneta pictipes, however that appears to be a more southern species.  Perhaps one of our readers will be able to assist in this identification.

Dan,
Because of the link and the update, I googled Neriene radiata and it is definitely the Filmy Dome Spider in my photos. What is even more confirming is that person’s observation that the courtship lasted for days.  I remember being very surprised when I kept seeing the pair for several days straight as I had assumed that all spider mating was a fairly quick proposition. Thanks for being such a great resource.  More to come from this bug-loving naturalist….

Hi D.K.,
Thanks so much for writing back to provide this identification update.  Your photos are stunning, and nearly identical to the image of mating Filmy Dome Spiders, Neriene radiata, from BugGuide.