Since tannins play multiple ecological roles, tannin structural diversity has presumably evolved
to benefit plants in these roles.
A more focused question is ‘‘What are the functional differences between different structures of tannins in such roles as deterrents, antimicrobials, and toxins?’
The effects of different tannin types on different types of insects (e.g., caterpillars, grasshoppers, sap-sucking insects) have yet to receive adequate attention.