Pollination of Fig Trees

Fig flowers lie on the inside of the fruit.

Perpetuation of fig trees and their pollinators depends on the mutual reltationship that exists between the trees and the wasps that pollinate them. Only certain fig wasp species can pollinate a certain type of fig tree. The wasp itself would have no home without the fig tree. In addition, each type of fig tree sustains only one specific type of pollinator wasp.

Fig Tree Description

The fig grows 10 to 30 feet tall with thick, twisting branches that stretch out wider than its height. Large, bright green foliage dots the branches, which produce a sticky sap when cut or bruised. Irregular-shaped, green fruit appear on its branches.

Fig Fruit and Flowers

Flowers of the fig tree present a problem to pollinators. According to Iziko South African Museum, the actual fig fruit conceals the flowers, as hundreds of minuscule flowers line the inside of a green fig fruit. A tiny ostile or pore offers the only way to reach the flowers of the fig. Some of the flowers have longer styles (the stem-like part of a flower) than others.

Pollinators

Fig wasps provide the only way for a fig tree to become pollinated. Depending on the season, wasp larvae take three to 20 weeks to reach maturity. Wingless male wasps serve only two purposes: to mate with the female wasps and chew holes in the fig for the female to fly from. With a long, flat head and thorax, the female wasp's body is perfectly adapted to climbing into a fig fruit. In addition, it bears back pointing teeth on the underside of its head and on the legs to prevent the wasp from sliding out of the fruit.

Process of Pollination

Once female wasps reach maturity, they leave the fig fruit in which they bred and go search for fig trees in which to pollinate. Due to their short life span and the long journeys to find a tree, few wasps actually manage to pollinate a fig tree. Female wasps recognize a fig tree ready for pollination by the chemical signal the fig tree gives out. To reach the flower, the wasp needs to enter through the pore of the fig fruit to reach the fig cavity.

Pollinating Fig Fruit

Once inside the cavity of the fig fruit, the female wasp lays eggs and pollinates the flowers. To accomplish the actual pollination, the wasp puts its ovipositor down the style to deposit an egg. Due to the varying length of the actual style, the egg does not always reach the end of the floret. In this case, the flower gets pollinated and forms a seed. Thus, the female wasp both lays eggs and pollinates a fig fruit. Once the wasp completes pollination, the fig begins to ripen and change color.

References

• Fig Web: How Fig Trees are Pollinated
• California Rare Fruit Growers: Figs
• Palomar College: Multiple Fruits Of The Mulberry Family

Resources

• Fig Web: Figs and Fig Wasps