[eng] This paper describes the presence of insect traces that appear in large quantities at the Pliocene <br> lower Pleistocene dune formations in Mallorca. We discuss two hypotheses about possible producers. It also reveals the mystery about the origin of these fossil traces that had been previously attributed to enigmatic organisms, faecal pellets or coprolites of Myotragus sp., are really insect trace fossils, attributable to the beetles pupation cameras. The presence of these fossil traces has a clear palaeoclimatic meaning which can be derived stratigraphic dating.