A Lepidopterous Cocoon from Thera and Evidence for Silk in the Aegean Bronze Age

Article excerpt

Elusive prehistoric trade

In the consideration of trade in prehistory, durable inorganic items such as pottery and metal dominate our view through their good chances of preservation. Organic materials which travel without durable containers, or within organic wrappings themselves, are more elusive in the archaeological record. Unusual preservation is provided by the thick tephra deposits burying the Bronze Age settlement at Akrotiri on the Aegean island of Santorini (Thera), where the cast of an insect cocoon provides insight into a largely invisible aspect of the Aegean world.

Context of the cocoon

The volcanic island of Santorini in the southern Aegean is well known for the settlement at Akrotiri, destroyed and buried by an eruption in the mid 2nd millennium Be. Excavation of the site began in 1967 under the directorship of Marinatos (1968-1976) and has continued since 1974 under Doumas (1983). Ten buildings have been excavated, some surviving to a height of three storeys beneath the blanket of tephra, with well-preserved wall-paintings, pottery, tools and furniture. On the microscale, preservation includes extensive charred deposits of stored pulses and cereals (Sarpaki 1993), the remains of insect pests of stored and field crops (Panagiotakopulu & Buckland 1991), weeds (Sarpaki 1993) and evidence for the use of natural insecticides (Panagiotakopulu et al. 1995). In the lower deposits, away from the direct charring influence of the hot tephra, preservation of organic remains is largely restricted to calcification and casts of some seeds and fly puparia in drains under the settlement. From recent excavations east of the House of the Ladies, a structure in the northern excavated area, beneath the destruction levels, there comes a calcified, slightly waisted, cylindrical object, 44 mm long and 18 mm wide, with flattened ends. One end is broken open, revealing a smaller ovoid structure within [ILLUSTRATION FOR FIGURES 1, 2 OMITTED]. This object is identified as a cast of a cocoon and part of the enclosed pupa. The associated group of finds, chronologically mixed, includes pottery ranging from the Early Cycladic period through to the phase immediately prior to the eruption. The delicate nature of the object and its fine preservation implies contemporaneity with the latest material; a mid-2nd millennium BC date is probable.

Identification of the cocoon

The good preservation of this find enables its identification. Several phyla of invertebrates utilize cocoons, and a number of Arthropods produce them to protect themselves during metamorphosis or, in the case of Arachnida, as egg cases/Roberts 1995). Among the Insecta, two Orders, the Hymenoptera and Lepidoptera, most frequently construct cocoons; they are also present in some Coleoptera and a few small Diptera. Apart from a few small skippers, the butterflies do not construct cocoons, but they are widespread among the moths (Carter & Hargreaves 1986). In the European fauna, the size and shape of the cocoon further limits the possibilities of identification to the larger moths, which construct freely spun cocoons, in particular some species of Lasiocampidae and Saturniidae. Only a few of the Lepidoptera, however, are sufficiently large to warrant discussion in relation to the Akrotiri find. The essentially urban archaeological context further limits interpretation since the context is not one likely to be used for the natural pupation of a large moth and it is more probable that the item was brought to the site and later discarded.

In the European fauna, two species, the saturniid, Saturnia pyri Den. [ILLUSTRATION FOR FIGURE 3 OMITTED] and the lasiocampid, Pachypasa otus (L.), have long been suggested as the source of the 'wild silk' of the Greek and Roman world (Kirby 1903; Zeuner 1963: 487). One of these two species is likely to have produced the Akrotiri cocoon and the size and morphology makes it is most likely to have been P. …