Figure 1.

All the 57 articles published in peer-reviewed journals that investigated TGIP in invertebrates. Articles quantifying the consequence of parental pathogen exposure on the outcome of infection in offspring (e.g., parasite prevalence and intensity, host fitness, and survival) are indicated as TER (trans-generational effect on resistance; gray color). Articles focusing on the impact on offspring immunity (e.g., number of hemocytes, modified expression or activity of AMPs, PPO, or immune pathways) are indicated as TEI (trans-generational effect on immunity; black color), following the updated nomenclature proposed by Pigeault et al. (19). Articles that evaluated both parameters are hatched in black and gray and indicated as TER+TEI. All information relative to the 57 TGIP articles published to date are available in Supplementary Table 1. Considering that the term TGIP is not used by all authors and that some investigated it without highlighting it clearly in the title and/or abstract, complementary searches were performed to retrieve all TGIP articles. Different search engines were used for identifying peer-reviewed (PubMed, Web of Science, Google Scholar, Biological Abstracts) and preprint articles (bioRxiv). We used different combination of keywords including notably “transgenerational immune priming,” “immune priming across generations,” “multigenerational immunity,” “vertical transfer immunity,” “maternal/parental transfer immunity,” “maternal/parental effect immunity,” “transfer immune memory,” “offspring immunity invertebrate,” “offspring immunity insect.” In addition, several articles dealing with within-generation invertebrate immune priming and immune memory were investigated for evidence of experimental design and results that relate to TGIP.