Early-life diet experience structures personalities and individual foraging niches of omnivorous predatory mites

Abstract

Joint consideration of the ideas of individual niche specialization and animal personalities predicts co-variation in personality expression and realized niche use. Animal personalities are characterized by within-individual consistency linked to consistent among-individual variation in behavior across time and contexts. Individual niche specialization posits that members of local groups should diversify in their foraging phenotypes to alleviate inter-individual competition and ensuing conflicts. Here, we tested the hypothesis that early life experiences shape individual foraging niches and personality expression in the omnivorous plant-inhabiting predatory mite Amblyseius swirskii. To this end, we exposed predatory mite females in their early life phase to one of three diets (pollen, spider mites or thrips) or no food (control) and later evaluated the adult females’ mean trait expressions and personalities in exploration, activity and aggressiveness. Personality formation was analyzed by intraclass correlation coefficients (ICC). The predators showed personalities in all three behavioral dimensions but personality formation and diet preference were strongly influenced by early-life diet experiences. Personality types in exploration were predictive of fitness, with more exploratory personalities producing more eggs. Thrips experience had the strongest impact across measured traits and thrips-experienced personality types were linked to individual foraging niches. Overall, early-life diet experiences induced greater changes in trait expressions at the individual than population level. Our findings highlight that ephemeral personal experiences early in life are important determinants of fine-scale phenotypic structure and diversity within groups, and demonstrate environmental induction of the link between individualized niche use and personality formation.