Pharmacological properties of blister beetles (Coleoptera: Meloidae) promoted their integration into the cultural heritage of native rural Spain as inferred by vernacular names diversity, traditions, and mitochondrial DNA

ETHNOPHARMACOLOGICAL RELEVANCE: Beetles of the family Meloidae (blister beetles) are often reported in pharmacological literature because of their content of cantharidin. Cantharidin has a long history in human medicine and was commonly applied in the 19th and the early 20th centuries, although its use has been progressively abandoned since then. Contrary to most, even common, large species of Coleoptera, blister beetles of the genera Berberomeloe, Physomeloe and to a lesser extent Meloe, are usually recognized and often incorporated into local folk taxonomy by inhabitants of rural areas in Spain. AIM OF THE STUDY: To demonstrate the role that pharmacological properties of blister beetles must have played in their integration in the culture of early Iberian human societies, but also in the preservation of their identity until today, a rare case for Spanish insects. To achieve this purpose we document the diversity of vernacular names applied in rural areas of Spain, and we determine, using molecular data, the antiquity of the presence of two species of the better-known blister beetle in rural Spain, Berberomeloe majalis and Berberomeloe insignis. MATERIALS AND METHODS: We try to document the extent of traditional knowledge of meloid beetles in rural areas by interviewing about 120 people from villages in central and southern Spain. We also use mitochondrial DNA sequences (Cytochrome Oxidase I and 16SrRNA) obtained from several populations of two species of the better known blister beetle in rural Spain, Berberomeloe majalis and Berberomeloe insignis, to determine whether these beetles were already present in the Iberian Peninsula when earlier ancient cultures were developing. RESULTS: Our results show that, based on mitochondrial DNA, blister beetles of the genus Berberomeloe were present in the Iberian Peninsula long before humans arrived, so ancient Iberian cultures were in contact with the same beetle species occurring now in rural areas. On the other hand, people interviewed in rural communities provided us with more than 28 different vernacular names, a few short songs incorporated to local folklore, and some therapeutic uses. CONCLUSIONS: Current knowledge of blister beetles of the family Meloidae in rural Spain was likely developed as a consequence of their pharmacological properties; we hypothesize this knowledge was inherited from ancient pre-Christian Iberian native cultures as part of their traditional therapeutic traditions. It is possible then, that current vernacular names and traditional songs are the only remnants of an ancient knowledge of pharmacological uses of meloid beetles, verbally transmitted from the ancestral cultures to modern day rural Spain. Our work suggests that this legacy, part of the European Cultural Heritage, is disappearing fast, in parallel to the loss of traditional agricultural techniques.