I was part of a really fun collaboration with Maria Moiron and Petri Niemela where we did a meta-analysis to test whether variation in individual behavior predicts variation in individual survival. We were able to actually get the raw data from all the included studies (thanks authors!) and so run the same models on all data, which I think makes the results even more powerful. You can read the full paper here.
We found that among-individual variation in behavior does explain variation in survival, but not a huge amount – only about 5%, and perhaps more surprisingly, not in the direction we generally predict. In fact, when we compared studies that had been in performed in the lab versus in the field, we found that bolder/riskier individuals were actually *more* likely to survive in field studies! How interesting! There are a couple important potential implications here. The key assumption underpinning the whole “pace-of-life” hypothesis and that riskier behaviors mediate a trade-off between resource acquisition and mortality risk. So either this assumption is wrong, or the behaviors we are measuring are wrong (in the sense they are not actually responsible for mediating the trade-off but some other behavior is).
In any case, I am very happy about this paper because it firmly shows that individual behavior does have important fitness (survival) consequences and that we may need to think more deeply about our current theory and what it means and what we are measuring. Plus, it was super fun to have a project to work on with two close friends-now-collaborators!