Starch analysis reveals prehistoric plant translocations and shell tool use, Marquesas Islands, Polynesia

Starch analysis is proving particularly useful in tropical regions like the central Pacific where crop inventories are often dominated by starchy fruits and tubers and recovery of macrobotanical remains is rare. Analysis of 23 shell tools from the Marquesas Islands provides direct evidence for translocation of five traditional crop plants. Four taxa derive from the western Pacific, including Artocarpus altilis (breadfruit), Piper methysticum (kava), Colocasia esculenta (taro), and one or more species of Dioscorea (yam). The fifth taxon, the South American Ipomoea batatas (sweet potato), dates from the 14th century AD onward and constitutes the earliest record of this cultigen in the archipelago. The occurrence of sweet potato starch suggests that this crop plant may have been more important than usually is assumed, while the limited recovery of breadfruit starch, the main Marquesan food plant at western contact, requires further investigation. The starch residues also inform on tool use, demonstrating that shell tools ethnographically associated with specific crops (e.g., “breadfruit peelers”) had more generalised functions. This study is a further demonstration of the potential of starch analysis to provide important information on the history of crop introductions, on-site activities, and artefact use.

► Shell tool residues (starch) inform on timing of five crop introductions to Marquesas Islands. ► Four of west Pacific origin (kava, yam, breadfruit, taro) and one South American (sweet potato). ► The economic importance of sweet potato possibly has been under-estimated. ► Residues also reveal unexpected uses of shell tools.