I was very excited to find this tiny pair steadily going at it in one of my Great Falls forays in July and kept the camera pointed at them for some time, just watching and trying to understand and get clear shots. And video! After I saw the male do this "flip-switch-empty-fill" thing with his palps a few times, I remembered my camera could take video and caught it there, hoping someone would be able to explain what he was up to.  I showed it to spider expert Mandy Howe, and pasted her explanation below the video I posted on YouTube. Very cool! She also linked me to this video of a jumping spider mating dance where the sounds she describes were actually captured. Amazing!  By the way, it was really hard to keep this to myself at the time. But I finally forgot about it till now. Glad I remembered before the month was up!   Filmy Dome Spiders Neriene radiata  Arachtober 26, 2010