The other day I decided to watch an ant to see what it was up to. It seemed to be just wandering around: it would go up one grass stem, cross over to an intersecting blade; go down the new blade only to go back up another blade. I suppose it was looking for food to take back to the nest but it only spent part of its time at ground level in the debris. What was it looking for when travelling the grassy high road above the ground level? I think the answer might be: "safety", for only a couple of minutes later when travelling along a twig at ground level the little guy was caught by a small dwarf spider.
It happened so quickly, I didn't realize what I had just seen before the poor guy was a goner. He got caught on a strand of sticky spider silk and quick as a flash the tiny spider ran out from its hiding spot and administered its poison. The spider and ant were evenly matched, but the ant while retreating from the advancing spider had got further tangled up in the spider's web. After the first brief battle the spider retreated and let the poison take effect. Every minute or so it would come back out from hiding to see how much fight was left in the poor fellow and then go back to its shelter to let the poison do its job. About 5 minutes after the initial battle the little ant had ceased to struggle. The spider came back out, used its silk to bind up the ant and then slowly dragged it back to its lair.
As a size reference I later measured the snail shell at the bottom of the above picture to be 7mm wide.