Insect pollinated flowers rely on bees, butterflies and other insects for pollination. Animals such as birds (e.g. hummingbirds, sunbirds) and bats also help in pollination.
Insect pollinated flowers possess the following characteristics:
- Large flowers with brightly colored petals to attract insects.
- Flowers are usually sweet smelling or fragrant with nectar present.
- Stigmas are usually small, compact and do not protrude out of the flower.
- Stamens are not pendulous and are located within the interiors of the flower, so that pollen can stick on the backs of pollinators as they brush against the anthers.
- Nectar guides present to guide the pollinators towards the nectar.
1. Blue Butterfly Pea / Clitoria ternatea
The native tropical plant, Clitoria ternatea or Blue Butterfly Pea is insect-pollinated. See photo taken from Alexandra Canal Park.
As it is a bisexual flower, it has male and female organs both in each mature flower. The sexual reproductive organs are enclosed by the two yellowish green keel petals and which in turn are covered by two purple-tipped wing petals. The green parts are the sepals (calyx). The yellow anthers with filaments, and surrounded by the stigma and style, can be seen (pointing at three o’clock).
The petals of Clitoria are harvested to make the blue dye used in coloring glutinous rice cakes. Yummy!
2. Spanish Shawl / Dissotis rotundifolia & Sendudok / Melanstoma malabathricum
Both plant species belong to the same family (Melastomataceae) and have insect-pollinated bisexual flowers consisting of:
- 5 purple petals (Spanish Shawl is deeper purple compared to Sendudok)
- 10 stamens– 5 stamens are larger with curved purple ends and 5 stamens are shorter with straight yellow ends. Notice the two lobes at the end of each short stamen.
- 1 carpel (curved in the centre)
While it is visited by bees and butterflies, the Carpenter bee is likely to be its primary pollinator as it prefers to feed on its flowers. See photos in Hort Park:
Top – Close up of Spanish Shawl flower
Middle – Fruits (left) & flowers (right) of Sendudok
Bottom – Carpenter bee feeding on nectar from Sendudok flower
Birds, butterflies, squirrels and monkeys feed on the fruits of the Sendudok!
3. Blue Trumpet Vine / Thunbergia laurifolia
The Blue Trumpet Vine (it belongs to a family of plants commonly known as “Morning Glory”) is a climber that grows well and flowers easily in Singapore’s climate.
It is visited/pollinated by Carpenter bees.
It is a bisexual flower with 4 stamens and 1 central carpel (notice the long style leading from the stigma to the ovary below).
The Blue Trumpet Vine originates/is native to India.
4. Orchids
The Orchid family, Orchidaceae is the largest family of flowering plants in the world. It is estimated that 10% of all flowering species are orchids! Orchid flowers are bisexual and insect pollinated in the wild, with the following characteristics:
- large, attractive and fragrant petals and sepals (3 sepals and 3 petals)
- highly modified third lower petal (called labellum/lip)
- nectar guides
- prominent pollen sacs (one pair)
See photos of VIP orchid, Dendrobium Hifikipunye Pohamba (bred in Singapore Botanical Garden) and the Slipper Orchid (planted in Cloud Forest, Gardens by the Bay), which is arguably the most prized group of orchids in the world!
The orchid, Vanda Miss Joaquim was selected as the National Flower of Singapore on April 1981.
5. Rose-Flowered Jatropha / Jatropha Integerrima
The Rose-flowered Jatropha is planted widely in parks in Singapore due to its attractive flowers with intense red petals and bright yellow-striped anthers.
It has unisexual flowers, i.e. separate female (top) and male (middle) flowers in the same plant. Each female flower consists of 3 carpels (with the ovary at the base). Each male flower consists of 10 anthers, lined with bright yellow pollen grains. See photos taken in Alexandra Canal Park.
It attracts butterflies and hummingbirds in the wild. In Singapore, Oriental honeybees have been observed feeding on its nectar and likely assist in its pollination.
The leaves and seeds of this plant are toxic and poisonous!
plantbiologyrs 