Prairie-relict
Guides
Antistrophus pisum
Antistrophus pisum is a species of gall wasp in the family Cynipidae. It is a synonym of Antistrophus lygodesmiaepisum, a monophagous cynipid wasp that induces pea-like stem galls on the rush skeletonplant (Lygodesmia juncea). The species occurs in the Loess Hills region of western Iowa and extreme northwestern Missouri, where its host plant persists as a hypsithermal relict in hilltop prairie remnants. The galls are solid, succulent structures that exude latex-like sap when damaged.