Although personality (consistent inter-individual differences in behavioural traits across time and/or contexts) and behavioural syndromes (suites of correlated personality traits) have been widely studied in the last decades, the origin and development of these traits during ontogeny are still underexplored. In this context, species undergoing metamorphosis are of special interest. To date, however, the persistence of personality traits has been only little investigated in organisms undergoing complete metamorphosis such as in holometabolous insects, although this kind of studies may provide important insights from a functional point of view. Here, we tested whether the personality and the behavioural syndrome are maintained through metamorphosis in Tenebrio molitor, a holometabolous insect species. We found that personality and behavioural syndrome were present in both larval and adult stages. However, larval personality and behavioural syndrome did not predict adult behaviour. We suggest that the complete reorganization during metamorphosis may have profound effect on the behaviour of the beetles. These results challenge the established common thought that personality should persist along an individual lifespan.