Spider Wasps (Pompilidae Family)
I have been observing the erratic behavior of Spider Wasps in the yard lately. These dark blue-black wasps land on foliage in sunny areas and quickly dart around looking for prey. The ones I have been photographing have large spines on their legs.
I was really excited to step outside and watch one dragging a paralyzed spider backwards across the patio. These wasps specifically hunt spiders for rearing their young.
"Most North American species thoroughly paralyze their arachnid victims and then drag them to some kind of nest, usually a burrow in the ground but occasionally a mud nest or a cavity in dead wood." "(S)pider wasp nests always include a single spider and a single egg per nest cell". (Insects, Their Natural History and Diversity)
It's great to see the diversity of insects in our yard increase, especially those that are predators like the Robber Flies and Parasitic Wasps that depend on other insects (or spiders) to be present to rear their young.