We were fortunate enough to get away to Austin, TX over the holiday weekend and saw at least one natural phenomenon that heretofore we had only seen on television. While walking to dinner we came upon two creatures, one was a tarantula (theraphosidae) of the genus aphonopelma. The other was a tarantula wasp (some locals call them tarantula hawks) which is a member of genera hemipepsis. This was the first tarantula we had ever seen outside of a zoo or pet store. It was large enough to command respect. The tarantula hawk is also a big insect (fun fact: it is the state insect of New Mexico). What made it interesting to happen upon them together is the two animals' relationship to one another. The tarantula hawk stings the tarantula, drags it to a burrow, lays a single egg on the abdomen of the spider, and seals the burrow (video available). Once the egg hatches, the larva enters the body of the tarantula to feed on non-vital tissues in the spider for as long as possible (that's not a great comfort to the spider, I presume) before pupating. I'm surprised I haven't had nightmares about this yet.
On another day we noticed a spider cocooning a dragonfly. Not being an expert on insects and arachnids, I cannot positively identify the type of spider (possibly one of several kinds of garden spiders or orb weaver spiders in TX) or the dragonfly. The dragonfly was not going to get away and the spider looked like it had a juicy meal. So over the weekend it looks like the score is arachnids 1 and insects 1.