Pollinator-mediated selection is an evolutionary process occurring in

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. They include all forbs (flowering plants without a woody stem), grasses and grass-like plants, a vast majority of ...

s, in which the foraging behavior of pollinators differentially selects for certain floral traits. Flowering plant are a diverse group of plants that produce seeds. Their seeds differ from those of

gymnosperm The gymnosperms ( lit. revealed seeds) are a group of seed-producing plants that includes conifers, cycads, '' Ginkgo'', and gnetophytes, forming the clade Gymnospermae. The term ''gymnosperm'' comes from the composite word in el, γυμν ...

s in that they are enclosed within a fruit. These plants display a wide range of diversity when it comes to the phenotypic characteristics of their flowers, which attracts a variety of pollinators that participate in biotic interactions with the plant. Since many plants rely on

pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametop ...

vectors, their interactions with them influence floral traits and also favor efficiency since many vectors are searching for floral rewards like pollen and nectar. Examples of pollinator-mediated selected traits could be those involving the size, shape, color and odor of flowers, corolla tube length and width, size of

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed ...

, floral rewards and amount, nectar guides, and

phenology Phenology is the study of periodic events in biological life cycles and how these are influenced by seasonal and interannual variations in climate, as well as habitat factors (such as elevation). Examples include the date of emergence of leav ...

. Since these types of traits are likely to be involved in attracting pollinators, they may very well be the result of selection by the pollinators themselves. Having a floral display that either attracts a variety of pollinators or is efficient in the exchanges that occur during pollination can have advantages for the

reproductive success Reproductive success is an individual's production of offspring per breeding event or lifetime. This is not limited by the number of offspring produced by one individual, but also the reproductive success of these offspring themselves. Reproduct ...

of plants. Thus, pollinator behavior is important to understand in relation to the evolution of flowering plants and in some cases pollinator behavior is thought to lead to specialized

pollination syndrome Pollination syndromes are suites of flower traits that have evolved in response to natural selection imposed by different pollen vectors, which can be abiotic (wind and water) or biotic, such as birds, bees, flies, and so forth through a process c ...

s where floral traits have co-evolved with their pollinators in a way that are a direct response to the selection occurring from their pollen vectors. However, many flowering plants don’t display morphology that excludes all pollinators except the one they co-evolved with. The most effective pollinator principle posits that floral traits reflect the adaptation to the pollinator that is efficient at transferring the most pollen. Selection might actually favor some degree of generalization while some flowers can also retain particular traits that allow them to adapt to a certain type of pollinator, but will ultimately be molded by the pollinators that are the most effective and visit the most frequently. This leads to shifts in pollination syndromes and to some genera having a high diversity of pollination syndromes among species, suggesting that pollinators are a primary selective force driving diversity and

speciation Speciation is the evolutionary process by which populations evolve to become distinct species. The biologist Orator F. Cook coined the term in 1906 for cladogenesis, the splitting of lineages, as opposed to anagenesis, phyletic evolution withi ...

Pollinator-mediated selection requires isolation and therefore cannot function in

sympatry In biology, two related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter one another. An initially interbreeding population that splits into two or more distinct species s ...

. Floral isolation is a consequence of pollinator behavior that reduces inter-lineage pollen transfer, which reduces

gene flow In population genetics, gene flow (also known as gene migration or geneflow and allele flow) is the transfer of genetic material from one population to another. If the rate of gene flow is high enough, then two populations will have equivalen ...

and increases the possibility for a transition to different syndromes. Isolation with no gene flow between populations allows for the development of distinct species, thus speciation is a result of

reproductive isolation The mechanisms of reproductive isolation are a collection of evolutionary mechanisms, behaviors and physiological processes critical for speciation. They prevent members of different species from producing offspring, or ensure that any offsprin ...

and can be driven by pollinator-mediated selection.

References

{{Evolution Pollination Evolutionary biology

See also

References