“Individual Differences in Behavior Explain Variation in Survival: a Meta-Analysis”, 2019-12-06 (; similar):
Research focusing on among-individual differences in behavior (‘animal personality’) has been blooming for over a decade. Central theories explaining the maintenance of such behavioral variation posit that individuals expressing greater “risky” behaviors should suffer higher mortality. Here, for the first time, we synthesize the existing empirical evidence for this key prediction.
Our results did not support this prediction as there was no directional relationship between riskier behavior and greater mortality; however, there was a statistically-significant absolute relationship between behavior and survival. In total, behavior explained a statistically-significant, but small, portion (5.8%) of the variance in survival. We also found that risky (vs. “shy”) behavioral types live statistically-significantly longer in the wild, but not in the laboratory.
This suggests that individuals expressing risky behaviors might be of overall higher quality but the lack of predation pressure and resource restrictions mask this effect in laboratory environments.
Our work demonstrates that individual differences in behavior explain important differences in survival but not in the direction predicted by theory. Importantly, this suggests that models predicting behavior to be a mediator of reproduction-survival trade-offs may need revision and/or empiricists may need to reconsider their proxies of risky behaviors when testing such theory.