GETTING CROSS ABOUT POLLINATION
Some only see them as pests, but bees and other insects play key roles in helping many trees produce the fruit we eat
Iwas standing in the back yard when I noticed bees and other insects hovering over the flowers on my coconut tree. This part of my yard is cemented and the coconut tree was planted in a big, woven plastic container and placed in one corner to provide shade. After many years the plastic disintegrated and as the coconut had grown very big, we could not transplant it to another container.
The tree was left there in that corner sitting on its mound of soil, but as it is just outside my kitchen it gets watered every day. I never expected it to bear fruit, but it did.
So these were the insects responsible for making my coconut tree bear fruit. In fact, coconut trees are monoecious, which means they have both male and female flowers in the same inflorescence. In other words, they are hermaphrodites, like pines and corn.
It is believed that monoecious plants are capable of self-pollination, but in fact they are wind pollinated; if the male and the female flowers open at the same time, the wind carries pollen from the male to the female flowers. However, research in the Philippines, a major coconut producing country, showed that pollination by insects more than double the coconut yield.
An eight-storey condominium behind my house blocks the wind so my coconut tree could not have been wind-pollinated. I stood fascinated as several insects flew from one flower to another. Would they be able to make the tree bear fruit again?
Bees, both honeybee and bumblebee, are important fruit tree pollinators, so if you see a beehive on one of your trees do not destroy it. The condominium behind my house has several Terminalia ivoriensis, known in Thai as hu krajong, in its back yard adjoining mine. One of the trees is planted so close to the fence that some of its branches hang over my calamondin tree.
A few years ago this hu krajong tree had a bumblebee hive on one of its branches on the other side of the fence and it fascinated me no end to watch it grow bigger by the day. I also observed how the insects left their hive in the morning and returned at dusk if they were not busy enlarging their hive, which had grown to the size of a platter.
One evening I was drawn by a commotion in the back yard of the condominium building. Five workers were trying to dislodge the hive by using a pole with a fire on its end. The fire burned the bees as they tried to fly away from their hive. When I asked the men why they were doing it, they said the insects posed a danger as they could kill a man with their sting.
I told the men that I had watched the bees from only two metres away and I had never been stung, and besides, the hive was nearer my house than the condominium building so they should not be too concerned about it. My protests fell on deaf ears and as I turned my back I heard shouts of joy as the men succeeded in dislodging the hive.
They then proceeded to collect the hive, as for them the young bees still in it were a delicacy. It has been five years since, and I have never seen a bumblebee again.
The role of insects in pollinating fruit trees should never be underestimated. On our farm we have a Ficus sycamorus, commonly known as sycamore fig or Pharaoh’s fig, which was propagated from a tree that its owner brought back from Egypt. The mother tree was already bearing fruit when it was propagated and therefore our tree should have started bearing fruit too.
But it has been six years since it was planted and it has grown very big with its characteristic wide-spreading branches rising from near the ground, yet it has not given us any fruit.
On its leafless branches our tree has borne sprigs of syconia (singular syconium), which are round, berry-like receptacles often mistaken for fruit but in fact hollow with numerous flowerlets inside. For the flowerlets to develop into fruit, they must be pollinated by a wasp which enters the syconium by piercing it at the bottom. I suspect the reason our tree could not yield fruit is that it must be pollinated by a certain kind of wasp which does not exist on our farm.
Most species of figs are pollinated by wasps, but Ficus carica, or edible fig, is parthenocarpic, which means its fruit or seeds can develop without the benefit of fertilisation. The fruit of the sycamore is inferior to that of the edible fig, but it was valued as food by the ancient Jews and Egyptians. In general, the wood of fig trees is soft, therefore it is neither useful nor durable. However, although the wood of the sycamore fig is soft and porous, it is said to be very durable, hence it is a favourite with coffin-makers.
The sycamore fig is also called Pharaoh’s fig as the ancient Egyptians carved its wood as coffins for the mummies of their pharaohs. The coffins were then placed in decorative containers known as a sarcophagus. When they were excavated after thousands of years of being buried underground, both the mummies and their coffins were found to be still intact.
I do not expect to be buried or cremated in a coffin made from the wood of our sycamore fig tree when I die. But even without fruit, it is a beautiful tree which provides me great pleasure while I am alive, and for me that should be enough.