Abstract: Cultural properties made from organic materials are easily damaged by biotic agents of different nature (insects, fungi, bacteria). In particular, wood artefacts are often attacked by insects which belong to taxa very distant from each other: basically that of Isoptera and that of Coleoptera. Furthermore, in the latter group, families that evolved along very distant lineages, i.e. powderpost beetles, anobiids and longhorn beetles, adopt various strategies to feed on wood. The functional morphology, as well as the taxonomy, the behaviour and ways of life, and the modes of attack turn out into different damages, different defence options and different risks. Therefore, a thorough and comprehensive knowledge of these biodeteriogens, mainly woodborers and termites in our case, as regards everything they are concerned with in their life, is essential, for defence, particularly when considering it as prevention. Many applied researches and, even worse, many common defence actions are not based on reliable data obtained from basic research but on hypothesis, common sense and suppositions with the obvious consequence of not being effective and so invalidating the sustainability of preventive conservation for the protection of cultural heritage. Monitoring, risk assessment and control, all need a deeper knowledge to be cogent. Examples are given.