Here’s the latest from Imroze and Arun. A couple years ago we had found surprising levels of variability in immune memory (“priming”), across 10 wild-collected flour beetle populations (Khan et al 2016, Ecology and Evolution). In our new follow-up paper, we figured out what may explain this variation, by systematically analysing change in various fitness components in the populations, after priming. In a nutshell, it appears that priming is beneficial both for reproduction and for survival; but the relative benefits of priming may trade off. So, priming is stronger in beetle populations that are more susceptible to the pathogen; but it is weaker in populations that have a larger investment in fecundity after priming. Read the paper to find out more!