January 2022
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Damin Dallas
By Damin Dallas
Field Guide

Driving along the banks of the ever-impressive perennial Sand River, it’s hard not to take note of the incredibly large trees that line the banks, trees that include jackalberries, Natal mahoganies and sausage trees. There, however, exists another tree species, one that is capable of reaching heights of up to 30 metres. Its yellowish - flakey bark, large green leaves and green tinged or reddish/orange fruits make the sycamore fig (Ficus sycomorus) a truly unique tree species.

Depending on conditions, these trees can live more than 200 years. Over the years holes form in their trunks and in turn provide homes for bats, tree squirrels, mice, snakes and other reptiles. It produces an abundance of fruit almost all year round. The prolific crop is an important source of nourishment, being eaten by a number of animal and bird species. Monkeys and baboons, birds such as African green pigeons, black-headed orioles and purple-crested turacos as well as bats eat the fruit directly from the branches, while antelope and warthogs devour what falls to the ground. The root system and buttressed trunk of this species, makes it relatively safe from being pushed over by elephants.

The flowers are tiny and are enclosed inside the fruits and are therefore never seen. It is inside these fruits that the survival of the fig and another species is ensured. These species cannot live apart from each other and so have an extremely important symbiotic relationship. Figs are pollinated by a highly specialized species of wasp (Ceratosolen arabicus) that breeds inside the figs. A pregnant female wasp leaves her natal fig through a tiny hole in the fruit, and flies to another tree, where she crawls in through the same hole created by another wasp.

While entering the fruit, she will transfer all the pollen from one flower to another, ensuring the survival of the tree. When she reaches the middle of the fruit, she will select a female flower in which to lay her eggs. After the larvae hatch, they eat the pulp of the fig and develop into adults. The males are wingless and will live their entire life cycle inside the fig. The male will pierce a small hole through the fig to reach a female where he will fertilize her and die shortly afterwards. She then leaves the fig, and the cycle continues. The gases released while the wasps are inside the figs prevent the fig from ripening, so these green fruits are ignored and not eaten, which ensures the process can be completed.