Briefly pollination can be defined as the transfer of pollen from anther of a male plant to the stigma, ovule or flower of a female plant of the same species. This pollen then fertilizes the plant. Only fertilized plants can make fruit and/or seeds, and without them, the plants cannot reproduce.
Monoecious plants are plants which either carry both male and female flowers on a single plant or have flowers that carry both male and female reproductive parts (bisexual / hermaphrodite) while diecious plants are plants in which the male and female flowers occur on separate specimens.
Some species of monoecious plants are able to self-pollinate e.g tomatoes and beans however in most instances pollination is due to zoophily whereby pollen is transferred by animals e.g. insects, rodents and birds.
The distribution of pollen by the wind is known as Anemophily and the flowers of plants pollinated by wind are often less showy. Hydrophily is a rather rare type of pollination during which pollen is transferred between plants by means of water. It occurs mainly in aquatic plants. Zoophily is possibly the most well known type of pollination which takes place by means of animals.
Many flowering plants are pollinated by birds (ornithophily) as well as bees and butterflies (entomophily) however there are many other animal species responsible for pollination. Bats, mice, lizards, mongooses, and baboons are only a few zoophilic pollinators.
There are numerous reasons why pollination is important for all life on earth. Approx. 78% of flowering and fruit bearing plant species depend on pollination to reproduce and develop fruits and seeds. Pollination ensure a healthy ecosystem that comprises of a variety of plant species which in turn serve as food and shelter for numerous animal species.
Pollination is also essential for the production of many food crops and without it we will not have many of our favourite fruit and veggies including avocados, berries, coconuts, bananas, melons, nuts, beans, watermelon, onions, tomatoes, pumpkin as well as tea plants, coffee, chocolate and tequila!!
It is no secret that our number one plant pollinator the bee is under threat of extinction and recently specially modified drones have been used to pollinate crops. Scientist are also working on developing a robotic bee to assist in pollination of essential food crops.
Pollination can be either diurnal, occurring during the day, crepuscular, occuring at dusk or dawn or nocturnal, occurring at between dusk and dawn.
Zoophilic nocturnal pollinators include porcupines, beetles, moths and of course bats. Many of these night time critters are more active at dawn or dusk rather than in the dead of the night and they are called crepuscular pollinators. Bats are mainly active at night and play a critical role in plant diversity.
Many of the flowers pollinated between dusk and dawn have white petals and/or are sweet smelling in order to entice and guide the pollinators towards them. The renosterveld species Hesperantha falcata (common Hesperantha or bontrok-aandblommetjie) is an indigenous example. The closed flower has a mauve colour but unfolds to reveal its inner white petals late afternoon/early evening. The blossoms release a beautiful sweet scent into the veld and attracts the pollinators to it.
Pollination done by bats is called chiropterophily. Many fruits are dependent on bats for pollination, such as mangoes, bananas, and guavas
South Africa is home to 56 bat species. Bats are a protected species but little is being done to help them. Despite the harmful myths bats have offer important ecological services – controlling insects and pollinating crops.
South Africa’s two baobab species, African baobab (Adansonia digitate) and montane African baobab (Adansonia kilima) are pollinated by several species of fruit bats. The baobabs large white blooms are nocturnal attracting this night-time critter with their scent. The flowers are large enough to support the weight of a bat while feeding. In turn the baobab also provides shelter for bats in the hollows and crevices in its mighty girth. The baobab, is often referred to as the tree of life, and offer important ecological services to the bushveld so this is one of nature important symbiotic relationships.
We have learnt that animals such as birds, bees, bats and moths play an important role in pollination. Rodents also play an important role in the pollination of a number of fynbos species especially the protea family.
Striped mouse, Cape spiny mouse and Vleirat play an important role in the pollination of several flowering plants including low growing leucospermum e.g. Leucospermum hypophyllacarpodendron and various proteas e.g. the sugarbush. Pollen is transferred from plant to plant when it sticks to their fur and whiskers when the feed on the sweet nectar.