American Lac Dye

American Lac Dye An untapped resource of the Sonoran Desert Christina Bisulca1, Chika Mori,2 Marilen Pool, 1 and Nancy Odegaard 1; 1: Arizona State Museum, University of Arizona; 2: Freer and Sackler Galleries, Smithsonian Institution 5th Tri-National Sonoran Desert Symposium, Ajo, Arizona, March 5-8 2018, Sonoran Desert Alliance Introduction Lac Dye from Asia Many scale insects from around the world produce red dyes that historically have had great economic importance, which continues today as they are natural, light stable and non-toxic. There are several species of lac scales endemic to the Sonoran Desert. These species (Tachardiella genus) are in the same family (Keriidae) as the lac scales of Asia used in the commercial production of lac dye. These insects host on a specific plants and produce a polyester exudate that encases the female insects and eggs. The exudate (shellac) has been used since ancient times by cultures of the Southwest as an adhesive and sealant. There is no historical evidence of the use of the dye, which is present within the insects and eggs. The dyes from four Tachardiella spp. of the Southwest were extracted and analyzed with liquid chromatography mass spectrometry (LCMS) at Smithsonian Institution. The dyes were determined to be laccaic acids, very similar in chemistry to lac dye. The lac insects from Asia have been used for centuries as a source of shellac and red dye. Excretion of Kerria lacca sold as shellac. This material is exported around the world as a clear coating and a plastic. Lac dye is the water soluble waste product in shellac processing. Lac insects of the Southwest a b c Commercial lac dye (Kremer Pigments) from Kerria lacca. This dye has been used for centuries as a pigment and textile dye and is still used today. Ming dynasty painting from FSG with pink paint made with lac dye Laccaic Acid A Laccaic Acid E Anthraquinone d Laccaic Acid B Laccaic Acid D Laccaic Acid C Many scale insects (superfamily Coccoidea) produce red dyes that have been exploited commercially. This includes cochineal, kermes, and polish cochineal. Chemically, all of these dyes are based on anthraquinones. Many other scales produce these dyes, but because of their commercial use, only these have been fully characterized. The anthraquinones in lac dye are called the laccaic acids A-E. The main component is laccaic acid A, followed by B; C-E are minor components. There are seven different species of lac insect in the greater Southwest, all in the genus Tachardiella. Shown above are the exudates on the host plant from the lac insects T. larrea (a), T. cornuta (b), T. mexicana (c), and T. fulgens (d).1 Each species hosts on a different plant. One of the most common insects in Arizona is T. larrea on creosote (Larrea tridentata) and often the lac exudate is called “creosote lac”. T fulgens, which hosts on coursetia glandulosa, is also found in the Sonoran Desert. Dye Analysis of American Lac Aqueous extract of dye from T. fulgens (left), same extract at pH 9. The raw extract is orange in color. Larvae from Tachardiella fulgens shortly after emerging from the lac exudate. TABLE 1 Cultural Use of American Lac The Hohokam, Mogollon and Anasazi used the polyester exudate as an adhesive and a sealant; the O’odham peoples used this material in a similar fashion in the historic period. Examples of the use of this material are shown below. Because lac is found on Anasazi artifacts on the Colorado Plateau, this suggests that this lac was an important material that was traded by these ancient cultures. Because lac on creosote has been found in archaeological sites, it has been assumed that this is the species that was historically exploited. However, it is possible that other species were used, although currently there is no method to determine which species produced the exudates in artifacts. Mogollon mosaic pendant (26365). The turquoise is glued to the shell with insect lac. Anasazi handle (1787) where lac was used to attach a stone point. Lac was commonly used in hafting throughout the cultures of the Southwest. The hole in this pottery vessel was repaired with insect lac. This was a common use of lac by the Hohokam and later the O’odham peoples. Left images: raw stick lac artifacts of Tachardiella larrea on creosote found in Ventana cave, a Hohokam site that was used into the historic periods. The presence of these raw materials shows how it was collected for later use. Ventana Cave also lies along a major trade route, suggesting that raw stick lac could have been traded in this manner. These are the only two samples of raw stick lac at ASM, and prove that at least T. larrea was used by the cultures of the Southwest. Dyes present in the stick lac from four species from the southwest were analyzed with LCMS (see Table 1). Like lac dye of Asia, the dye contains various anthraquinones. Based on UV/Vis, some are red and some are yellow (see the orange dye extract, left). However, in Tachardiella spp. the predominant laccaic acid is B, and A is not present at all. Sample Mass (M-1) UV/vis max (nm) Type Culture 538 490 Treatment LA C 576 426 592 489 287 493 #1 #2 #3 479 432 LAC Y1 LAC Y2 536 491 495 491 550 491 313? 432-436 485? 415 269 432 285 466 #5 LA A LA B #6 LA D? #8 #9 # 10 Major Major Major Minor Major Trace Major Major Stick lac none none Tachardiella fulgens Stick lac none Minor Major Tachardiella fulgens (SI) Stick lac none Trace Major Tachardiella larrea (SI) Stick lac none Tachardiella mexicana (SI) Stick lac none B-89-X (T. larreae, ASM) Trace Minor Minor Trace Major Major Major Major Culture Stick lac O'odham none F68.18 (DIA) Pottery repair O'odham Heated A-39044 (ASM) A-41156 (ASM) 1787 (ASM) Pottery repair Ball Handle Mosaic pendant Hohokam Hohokam Anasazi Heated Heated Heated Mogollon Heated 26365-X-1 (ASM) Trace 283 452 Asian lac (Kerria lacca) Tachardiella cornuta (SI) Artifacts: Trace 520 432 Trace Trace Trace Major Major Trace Major Minor Minor Trace Major Minor Minor Major Major Major Major Minor Major Major Trace Minor Trace Trace Major Major Major The table shows other anthraquinones found in Tachardiella species. Based on molecular weight, compound #4 has the same structure as LA B but with one less hydroxy (OH) group. The extracts contain other related anthraquinones, and more work needs to be done to characterize the molecular structure of these components. Importantly, there are differences in the dyes present within each species. Table 1 also shows results from the dye extracted from shellac used on archaeological artifacts at ASM (see objects, left). Many anthraquinones were still present, even though the lac would have been heated during processing prior to use. With more research, it is hoped that these dyes can be used as a chemical marker to identify the species used historically by the various cultures of the Southwest. This research was supported in part by grants from National Endowment for the Humanities Save America's Treasures Grant (NEH-SAT PT5021411) and the Institute of Museum and Library Services Collections Stewardship Grant (IMLS MA-30-14-0528-14). The authors thank Brunella Santarelli, Gina Watkinson, Mike Jacobs, Suzanne Ekert and Martina Dawley at the Arizona State Museum, Aaron Steele, Detroit Institute of Arts, and Scott Schneider at the USDA ARC. 1. Stick lac samples from the Smithsonian National Museum of Natural History at Beltsville/Systematic Entomology Laboratory at the United States Department of Agriculture, Agricultural Research Service (USDA ARC).