A survey of plant and insect exudates in the archaeology of Arizona

The Arizona State Museum has more than 30,000 archaeological perishable artifacts. A large scale inventory of this collection led to an analytical survey to identify the indigenous adhesives that are present in these objects. Adhesive samples from 64 objects that covered 31 different archaeological sites and encompassed every major cultural tradition in Arizona were analyzed with attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The study found that Pinaceae exudates and insect lac were the primary adhesive materials. Insect lac was the predominant adhesive used by the Hohokam, and both pine resin and insect lac were found in artifacts from the Mogollon and Ancestral Pueblo. Because insect lac is produced by insects (Tachardiella spp.) endemic to the desert lowlands, this indicates exchange of insect lac throughout the cultural regions of Arizona. This study illustrates the value of addressing a collection as a whole to increase understanding of prehistoric material culture and fabrication technology.