I often see these narrow waisted solitary wasps on carrot family flowers, mint flowers, summer sweet bush, etc. And they inevitably come to explore if I water a garden bed, looking for just that right consistency mud to build their nests with. The amount they carry off at a time is tiny, no more than 1/8 to 1/4" diameter ball.https://www.ag.ndsu.edu/yardandgardenreport/documents/2014-08-04/the-coolest-insecticide wrote:She goes back and forth carrying drops of mud to build the nests (see bottom photo). When completed, the nests looks like clay pots hand thrown on a potter’s wheel; thus the name “potter†wasp.
After making a nest she fills it with caterpillars, typically 1–12 caterpillars. She hunts down each caterpillar and then stings it with just enough venom to paralyze it, but not kill it. She then carries the caterpillar and drops it into nest. This hunting can take several days. Some of the literature reports the mother knows how many caterpillars to put in the nest: five or fewer for a male egg; more for a female.
There is a group of somewhat larger wasps called MUD DAUBERS -- they are known for using spiders as their prey, but apparently, there are subgroups that also prey on caterpillars and even cockroaches.