17 March 2019

Assorted Nectaring Plants - Part 4

Butterflies' Nectaring Plants
Assorted Flowering Plants - Part 4

A Blue Glassy Tiger feeding on the flower of the Belimbing (Averrhoa belimbi)

We are back with a selection of another six flowering nectar plants that butterflies visit for their source of energy to go about their daily activities. These plants, on the other hand, have adapted their reproductive parts to suit their pollinators e.g. bees, butterflies, moths, etc., to ensure the continual survival of their species. As most people would know, in the process of feeding on the nectar from these flowers, butterflies help to pollinate the plant which enables fertilisation and the production of seeds for the next generation of the plant.

A Dark Glassy Tiger feeding on the yellow flower of the Pig's Grass (Synedrella nodiflora)

Butterfly-plant relationships are not limited to their caterpillars that feed on their specific host plants. Adult butterflies have a preference for different types of flowering plants for their nectar source. Whilst many butterflies have their preferred or favourite flowers, this series of assorted flowering plants showcases various other types of flowers that butterflies occasionally visit for their daily liquid diet.

19. Bougainvillea (Bougainvillea glabra) hybrids

Colourful bracts of the Bougainvillea makes it a popular landscaping plant.

This attractive flowering plant is almost synonymous with the urban landscape of Singapore - from the time a visitor arrives at Changi Airport and takes a drive down the tree-lined East Coast Expressway into town. The colourful bracts of the Bougainvillea comes in many colours from white and yellow to pink and red. They adorn roadside verges, overhead bridge planters and are commonly seen as a decorative plant in public and private gardens.

Despite its showy colourful bracts, the actual flowers from which butterflies extract nectar are small and insignificant. These flowers are creamy-white, tubular and inconspicuous. Although the plant is common all over Singapore, butterflies are rarely attracted to the flowers for nectar. Only occasionally are butterflies observed to feed on the flowers for nectar.

A Tree Flitter probes deep into the tubular flower of the Bougainvillea

I have observed urban species like the Painted Jezebel, a couple of Glassy Tigers and some Swallowtails visiting the flowers for a quick re-fuelling stop, but they do not stay for long, or flutter from flower to flower on the plant to feed, unlike many of the other favourite nectaring plants. In the nature reserves, the occasional Skipper (Hesperiidae) are encountered feeding on the Bougainvillea flower in the early morning hours.

20. Pig's Grass (Synedrella nodiflora)

A Suffused Flash feeding on the flower of the Pig's Grass

This herbaceous plant can grow up to about 1-2m high and can be found along roadsides and wastelands. It appears to be more common in the backmangrove areas like Sg Buloh Wetland Reserves and Pulau Ubin. The small yellow flowers can sometimes be mistaken for the more common creeper, the Singapore Daisy (Sphagneticola trilobata) which belongs to the same Asteraceae family as the Pig's Grass.

A Spotted Black Crow feeds in the yellow flower of the Pig's Grass

The yellow ray florets attract a number of Danainae like the Glassy Tigers and some of the Crows. At Sg Buloh, we have observed some Lycaenidae like the Suffused Flash and Singapore Four Line Blue feeding on the yellow flowers. The primary pollinator of this plant appears to be bees and wasps, and they are more often seen on the flowers than butterflies.

21. Malayan Eyebright (Legazpia polygonoides)

A Plain Lacewing feeding on the flower of the Malayan Eyebright

This slender herb is classified under the Torenia family, which comprises low ground creeping weeds that grow amongst the grass in open gardens and landscaped lawns. The leaves are small, rounded with toothed edges. The plant flowers frequently. The small flower has a lower white lip of three lobes, and upper lip of red. The centre is tinged with yellow.

The small unique flower of the Malayan Eyebright contains nectar which some butterflies feed on

The diminutive flowers usually attract the smaller butterflies in the Lycaenidae and Hesperiidae families, but the Grass Yellows and Tree Yellow have been observed to stop and feed on the flowers as well. It was a surprising observation when the rare and elusive Plain Lacewing (Cethosia methypsea methypsea) was photographed feeding on the flowers of the Malayan Eyebright in the early morning hours.

22. Belimbing (Averrhoa bilimbi)

A Blue Glassy Tiger feeding on the pretty red flower of the Belimbing

This medium-sized tree can grow from 5-10m tall. Originating from Southeast Asia, the Belimbing is known for its very sour fruits that are used as a relish or garnishing in local cuisine. It is also closely related to its more well-known cousin, the Starfruit (Averrhoa carambola). A unique feature of the Averrhoa plants is that they flower and fruit directly on their trunks and branches.

The flowers and fruits of the Belimbing growing off the branches of the tree

A Common Grass Yellow feeding on the flower of the Belimbing

The flowers are small purplish-red, borne in a pendulous panicle inflorescence. Each flower is 5-petaled and fragrant, and each inflorescence has about 60 flowers, usually growing off the trunk or branches of the tree. Occasionally, the flowers attract butterflies like the Glassy Tigers and Grass Yellows. I have not yet recorded any other species of butterflies feeding on the flowers.

23. Common Vernonia (Cyanthillium cinereum)

A Lesser Grass Blue feeding on the flower of the Common Vernonia

Previously known as Vernonia cinerea, this wild-growing weed usually found along roadside green verges, open wastelands and even cracks in the joints of paved concrete footpaths. It grows as a small herb and the stalks of the flowers grow upwards with several flower heads on a single stalk. The purplish to white flowers comprise fine disc florets to which small butterflies are attracted.

Various species of the Grass Blues like the flowers of the Common Vernonia as a nectaring source

Due to its very small size, this wildflower attracts the smaller Lycaenidae like the Lesser Grass Blue and the Pale Grass Blue. It is highly unlikely that any of the larger butterflies can feed on the Common Vernonia as it is 'designed' for only the very fine and small diameter proboscis of small butterflies that are able to feed on it.

24. False Heather (Cuphea hyssopifolia)

A Metallic Caerulean feeding on the flower of the False Heather

This low-growing shrub with fine leaves are often used in landscaping as a border plant to line footpaths or planters. The bright green leaves are opposite and pointed. A native of South America, the False Heather was probably introduced to Singapore as an ornamental plant used in cultivated landscaped gardens.

A Yellow Grass Dart feeding on the flower of the False Heather

The small purple flowers occasionally attract butterflies to feed on them when there is a shortage of other more popular nectar-laden flowering plants are not available. Amongst the species that have been observed to visit the flowers for nectar are Striped Albatross, the Grass Yellows, and other small Lycaenidae and Hesperiidae species.

Text by Khew SK : Photos by Chng CK and Khew SK

Assorted Nectaring Plants - Part 1
Assorted Nectaring Plants - Part 2
Assorted Nectaring Plants - Part 3