Conifers protect themselves with resin. This resin contains diterpenes, which act as defenses against pests. Researchers at the Max Planck Institute for Chemical Ecology and Iowa State University have shown that some of these diterpenes existed before conifers evolved, while others developed independently in different tree species at a later stage, presumably to protect against bark beetles. A key factor in this process is a mechanism known as ‚epistasis‘, whereby earlier genetic changes pave the way for new traits. These findings enhance our understanding of plant defense mechanisms and could lead to more sustainable plant protection methods.