Fig. 2

Temporal trends in the map. a Timeline of numbers of published empirical papers split by different categories of paternal exposures (the same colour scheme is maintained in Fig. 4). b Timeline of numbers of published non-empirical papers split by type of publication. Among non-empirical records, ca. 80% are written as narrative reviews, followed by a smaller number of commentary/perspective works. Very few papers belong to systematic review family, and they are all from a medical cluster (e.g. [32,33,34]). Theoretical papers, presenting formal models, are even less frequent. The existing ones usually take evolutionary and/or ecological perspective [35,36,37,38], with the exception of one focused on the mechanisms of transgenerational inheritance of paternal stress [39]. c Primary (inner circle) and secondary (outer circle) topics of non-empirical studies broken down according to major taxonomic groups of considered organisms