Each species of fig is pollinated by one or a few specialised wasp species, and therefore plantings of fig species outside of their native range results in effectively sterile individuals.
For example, in Hawaii, some 60 species of figs have been introduced, but only four of the wasps that fertilize them have been introduced, so only four species of figs produce viable seeds there and can become invasive species.
This is an example of mutualism, in which each organism (fig plant and fig wasp) benefit each other, in this case reproductively.

The intimate association between fig species and their wasp pollinators, along with the high incidence of a one-to-one plant-pollinator ratio have long led scientists to believe that figs and wasps are a clear example of coevolution.
Morphological and reproductive behavior evidence, such as the correspondence between fig and wasp larvae maturation rates, have been cited as support for this hypothesis for many years.
Additionally, recent genetic and molecular dating analyses have shown a very close correspondence in the character evolution and speciation phylogenies of these two clades.

According to meta-analysis of molecular data for 119 fig species 35% (41) have multiple pollinator wasp species.
The real proportion is higher because not all wasp species were detected.
On the other hand, species of wasps pollinate multiple host fig species.
Molecular techniques, like microsatellite markers and mitochondrial sequence analysis, allowed a discovery of multiple genetically distinct, cryptic wasp species.
Not all these cryptic species are sister taxa and thus must have experienced a host fig shift at some point.
These cryptic species lacked evidence of genetic introgression or backcrosses indicating limited fitness for hybrids and effective reproductive isolation and speciation.

The existence of cryptic species suggests that neither the number of symbionts nor their evolutionary relationships are necessarily fixed ecologically.
While the morphological characteristics that facilitate the fig-wasp mutualisms are likely to be shared more fully in closer relatives, the absence of unique pairings would make it impossible to do a one-to-one tree comparison and difficult to determine cospeciation.
Each species of fig is pollinated by one or a few specialised wasp species, and therefore plantings of fig species outside of their native range results in effectively sterile individuals. For example, in Hawaii, some 60 species of figs have been introduced, but only four of the wasps that fertilize them have been introduced, so only four species of figs produce viable seeds there and can become invasive species. This is an example of mutualism, in which each organism (fig plant and fig wasp) benefit each other, in this case reproductively.
The intimate association between fig species and their wasp pollinators, along with the high incidence of a one-to-one plant-pollinator ratio have long led scientists to believe that figs and wasps are a clear example of coevolution. Morphological and reproductive behavior evidence, such as the correspondence between fig and wasp larvae maturation rates, have been cited as support for this hypothesis for many years. Additionally, recent genetic and molecular dating analyses have shown a very close correspondence in the character evolution and speciation phylogenies of these two clades.
According to meta-analysis of molecular data for 119 fig species 35% (41) have multiple pollinator wasp species. The real proportion is higher because not all wasp species were detected. On the other hand, species of wasps pollinate multiple host fig species. Molecular techniques, like microsatellite markers and mitochondrial sequence analysis, allowed a discovery of multiple genetically distinct, cryptic wasp species. Not all these cryptic species are sister taxa and thus must have experienced a host fig shift at some point. These cryptic species lacked evidence of genetic introgression or backcrosses indicating limited fitness for hybrids and effective reproductive isolation and speciation.
The existence of cryptic species suggests that neither the number of symbionts nor their evolutionary relationships are necessarily fixed ecologically. While the morphological characteristics that facilitate the fig-wasp mutualisms are likely to be shared more fully in closer relatives, the absence of unique pairings would make it impossible to do a one-to-one tree comparison and difficult to determine cospeciation.
Ficus