Maternal diet exerts sex-specific effects on offspring' personalities in predatory mites

Animal personality is characterized by consistent behavior within individuals linked to consistently variable behavior among individuals in a population across time and contexts. Genetic determination, transgenerational effects, and personal experience are major pathways shaping animal personalities. Among these pathways, little attention has been paid to environmental factors in the parental generation affecting offspring personality. Here we tested the effects of the maternal diet on offspring personality in the plant-inhabiting predatory mite Amblyseius swirskii. Mated females and males, whose mothers were fed during egg production on either cattail pollen, two-spotted spider mites, or thrips, were subjected to a battery of three to five tests each for exploration, activity, and boldness. Movement activity was assessed in the mites' familiar environment. Exploration was quantified by the latency to leave and reach novel sites or objects. Boldness was evaluated by residence in risky and benign sites. Mean behaviors were analyzed by generalized estimating equations, repeatability was assessed by intraclass correlation coefficients. On average, offspring from spider mite-fed mothers were the most active and those from pollen-fed mothers were the shiest. Offspring from thrips-fed mothers were more repeatable in activity than offspring from pollen- and spider mite-fed mothers. Consistently little and highly active personalities produced more eggs than inconsistent, flexible types. Only offspring from pollen-fed mothers were repeatable in boldness. Maternal diet did not influence offspring' personality in exploration. Taken together, our study suggests that the maternal diet critically influences both mean behavioral trait expression and behavioral repeatability of offspring. The ability of mothers to respond to short-term diet changes during internal egg production allows to adaptively adjust the behavior and personalities of daughters and sons within local and regional groups.