A research team shows in a new study how leaf beetles could successfully use new and previously indigestible food sources in the course of evolution. The insects acquired enzymes from microorganisms via horizontal gene transfer that enabled them to degrade pectins, solid components of the plant cell wall. Since the degradation products resulting from pectin digestion are not per se crucial for the growth and development of the beetles, the researchers conclude that the beetles disrupt the cell wall to access the protein-rich cytoplasm of plant cells, which they need for their nutrition.