Ants of the species Messor barbarus modify the grain size and mineralogical composition of the soils they inhabit, influencing the results obtained in palaeoclimatic and palaeoenvironmental studies, according to research conducted by the Complutense University of Madrid (UCM), the National Museum of Natural Sciences (MNCN), the Institute of Geosciences (CSIC, UCM) and the Doñana Biological Station (CSIC).