Research update on hymenopteran nests and cocoons, Upper Triassic Chinle Formation, Petrified Forest National Park, Arizona

This paper updates our work-to-date on the bee and wasp (Hymenoptera: Aculeata) nest ichnofossils first discovered in Petrified Forest National Park (PEFO), Arizona, in 1993. Recent work includes the collection and the identification of new localities of bee nests and wasp cocoons (these are not elaborated on here to protect the sites). These hymenopteran ichnofossils were compared to other insect traces of nests and cocoons to demonstrate the differences in their architectures. The Triassic material was also compared to other bee and wasp nest and cocoons ichnofossils to illustrate their similar architecture. This is important because the ichnofossil evidence suggests that hymenopteran behavior has changed very little over 220 million years and that they were pollinators of plants in Triassic terrestrial ecosystems.