Okay, forgive me for this one - but I had never seen it before and I find it interesting, despite feeling like a 3rd grader as I share it.
Yesterday I took a lot of photos of the insects that were visiting my Echinacea, since they're in full bloom and not much else is going on right now. As I photographed, I kept an eye on this little crab spider, wondering what it was going to capture, if anything. Multiple skippers and small butterflies visited the flower it was guarding, but I didn't see it attack anything, although it was obviously in hunting position.
Six minutes later, the crab spider was still in its hunting posture in its favored location on the bloom...but the drop of white liquid had disappeared. Evaporation? Something had lapped it up and I somehow missed it? I was still in the same spot, photographing other insects on other blooms. The liquid fell off the petal? I don't think that last possibility occurred, because there was nothing on the leaf below, which the white drop would have had to land on.