Early-life intraguild predation risk produces adaptive personalities in predatory mites

Animal personalities are defined by within-individual consistency, and consistent among-individual variation, in behavior across time and/or contexts. Here we hypothesized that brief early-life experience of intraguild predation (IGP) risk has enduring phenotypic effects on personality expression in boldness and aggressiveness in later life. We tested our hypothesis in predatory mites Phytoseiulus persimilis, which are IG predators with ontogenetic role reversals, i.e., they are potential IG prey during early life but IG predators as adults. Adult P. persimilis females, which had experienced IGP risk early in life or not, were subjected to three tests each for boldness and aggressiveness. IGP-experienced individuals were on average bolder and more aggressive. Boldness was moderately repeatable, aggressiveness was weakly repeatable. Strikingly, early-life IGP experience shifted the within-group personality composition toward consistently bold and aggressive personalities. Phenotypic adjustment of personality expression was adaptive, as indicated by the positive correlation between personality scores and egg production.