Hi Martin, It's a European paper wasp (Polistes dominula), an invasive species to the US. They use chewed plant material to make their nests (made from "spit balls") under your eves, sheds, under the hood of your car etc. But I've never seen them do that. Must make a fine pulp! I read once, some plants in the Iridaceae don't provide nectar, but rather entice pollinators with floral oils that specific pollinators feed on. Travis Owen Rogue River, OR amateuranthecologist.blogspot.com http://www.pacificbulbsociety.org/