The Interaction Affinity Between Flowers and Their Pollinators

Zaal Kikvidze

It is a common knowledge that the probability of the fertilisation of a flower by its pollinator is a function of species abundances. However, this relation was rarely formalised for analysing pollination networks. In this opinion paper, a simple model borrowed from physical chemistry is introduced to formalise this functional dependence. This led to a well-known biochemical concept of affinity, which refers to the strength of the binding interaction of a protein to its ligand. This affinity is explained as the “attraction” or “fit” between the two molecules, and is attributed to complementarity or the precise matching of the protein's active site and the ligand's shape, charge, and hydrophobic or hydrophilic properties. Analogously, we can think of a complementarity between the pollinator and flower morphologies, the ability of a pollinator to locate the desirable flower, which might involve sophisticated behaviours and the use of memory. The protein-ligand affinity is considered to be crucial since it determines how effectively the metabolism functions. We can think in similar terms when analysing pollinator-flower interactions: affinity can define the effectiveness of a pollinating networks and give us new insights about its functional mechanisms.