Today I discovered that there is no activity around the nests. I checked them after finding my broccoli chewed up pretty good. I haven't had that happen for years, because the wasps take care of the larvae. I haven't had wormy heads since I found out they went after them. We haven't sprayed any chemicals. The only change was this spring when we emptied the pool to re-level it and it was empty for a few weeks. They do get water from it part of the time. Any thoughts or has anyone else seen a shortage of them? I like having them around and hate to see them gone. It's so strange since they've been nesting around our house all the time we've lived here, about 14 years. Would bats go after them? I think we have one roosting in the rolled up shade under one nesting area. Any thoughts? I've just taken them for granted for years.