Taphonomy on the beach: experimental approach to bone modifications made by insects on an island (Gran Canaria, Canary Island, Spain)

Abstract

Insects play a crucial role in cadaveric decomposition, yet their contribution to taphonomic alterations on bones is often overlooked. This study investigates insect activity's impact on bone surface modifications under different environmental conditions. Five unfleshed pig heads were subjected to varied settings-buried and exposed-across coastal and inland contexts. Nine insect taxa were identified, including flies (Sarcophagidae, Calliphoridae [Chrysomia albiceps], Fanniidae, Muscidae), beetles (Dermestidae [Dermestes maculatus], Cleridae [Necrobia rufipes], Hydrophilidae [Cercyon cf. arenarius]), ants (Formicidae [Tetramorium depressum]), and termites (Kalotermitidae [Cryptotermes brevis]). Taphonomic changes observed on bone surfaces varied between buried and exposed specimens, with greater insect diversity and more pronounced modifications in exposed samples. Striations, linear marks, perforations, and bone destruction were linked to specific insect taxa, revealing novel osteophagic behavior in certain species. Termite activity, identified by faecal pellets, occasionally resulted in bone damage. Notably, beetle-induced alterations were absent in coastal environments, suggesting post-decomposition transport when these modifications appear on bone elements from coastal sites. This is the first experimental study in archaeoentomology, providing critical insights into insect-driven taphonomic processes in coastal and inland archaeological sites, with implications for forensic and archaeological interpretations of bone alterations.