I went for a hike at Castlewood Canyon State Park this last weekend and observed dozens of Mountain ball cacti (Pediocactus simpsonii) blooming. This one was in the process of being pollinated by a bee. I watched the bee for a while and then snapped this photo as an ant crept up and attacked it! The startled bee managed to fly away and leave the ant behind. It returned a minute or so later, after the ant had left, to continue pollinating the blooming cactus.