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

10 March 2019

Butterfly of the Month - March 2019

Butterfly of the Month - March 2019
The Common Four Ring (Ypthima huebneri)

A Common Four Ring perches on the tip of a leaf with its wings folded upright

The hot humid month of March is upon us, as temperatures seem to soar much higher than usual. The weather app on my iPhone appears to read above 32degC on most days for the past couple of weeks and the "feels like" temperatures can top 38degC around noon. The high Relative Humidity doesn't help much, as the short occasional showers just made it worse.

Our general landscape in the parks and gardens looks parched and dry and trails that we have walked in the nature reserves recently are crackling with dry leaf litter. The meteorological station's forecast predicts more hot weather in the coming weeks. During such months, water is more precious than usual, both for us humans and everything else in our natural world.

Speaking of water, it has been very much in the news of late, and our 'friendly' nonagenarian politician up north has been harping on an age-old issue of the price of water that Singapore buys from neighbouring Johor. Despite Singapore's efforts to be self-sufficient in its own supply of potable water via PUB's four national taps, one national tap - imported water from Malaysia, still makes up at least 20% of the daily demand.

A Common Four Ring opens its wings to sunbathe in the early morning hours of the day

Under a 1962 Water Agreement with Malaysia, Singapore is allowed to draw water from the Johor River and Linggiu Reservoir, with a provision that Singapore treats and provides 2% of this water back to Johor. The supply from this imported source is up to 250 million gallons of water per day up to 2061 - 51 years left to go.

The current dispute over the price of water is a thorny issue that continues to strain bilateral ties - depending on the politicians of the day. Only when Singapore completely eliminates this dependence on Malaysia for its water needs, will this off-again, on-again threats continue. It is only when our taps run dry, or when fresh clean water becomes unavailable, that we realise the importance of this critical natural resource that we normally take for granted.

A mating pair of the Common Four Ring

Our Butterfly of the Month for March 2019 is a small and usually under-appreciated Satyrinae, the Common Four Ring (Ypthima huebneri). The genus that this species belongs to comprises small, greyish-brown and streaked butterflies that frequent open grassy habitats at the forest edge. The English common name for the "Ring" butterflies refer to the number of rings on the hindwing of the various species.

The Common Four Ring is the smallest of the Ypthima species in Singapore. Rather local in distribution, the species is not considered very common except at the handful of habitats which it favours. It is a weak flyer and stays close to the ground in shaded grassy areas near the nature reserves. As its caterpillar feeds on the grass Ottochloa nodosa, it is usually found in the vicinity of its host plant. Where it occurs, usually several individuals are seen together.

The Common Four Ring has a greyish-brown undersides with fine striations on both wings. The forewing has a large yellow-ringed black ocelli with a pair of bluish dots within the black ocelli. The hindwing has four yellow-ringed black ocelli with a blue dot in each of the black ocelli. The arrangement, size and contiguity is very variable and the spectrum of diversity is discussed in an earlier article here.

Common Four Rings feeding on various flowers

Both males and females of the Common Four Ring are observed feeding on flowering plants in the forested areas, like Mile-A-Minute, Bandicoot Berry, Singapore Daisy and others. In the early morning hours, the butterfly can be seen fluttering around low shrubbery and grasses and then stopping to open its wings to sunbathe. As the day progresses and it gets warmer, the Common Four Ring tends to stop to rest with its wings folded upright.

It is also interesting that, for such a small butterfly that is moderately common, its total life history takes about 45-50 days from egg to eclosion - relatively long. The host plant, a common grass that grows easily along cleared forest edges, is also a host plant to at least five Hesperiidae, other Ypthima spp. and Mycalesis spp. So a common humble grass is important to these species of butterflies for their continued survival.

Text by Khew SK : Photos by David Chan, David Ho, Khew SK, Koh CH, Loh MY and Loke PF.

02 March 2019

Assorted Nectaring Plants - Part 3

Butterflies' Nectaring Plants
Assorted Flowering Plants - Part 3

A male Common Birdwing feeding on the flower of the Hibiscus

In the next part of our observations of butterflies' nectaring plants, we feature a further six species of flowering plants which butterflies visit to feed upon the flowers. Again, we reiterate that some of these attractive-looking and colourful flowers (to us humans) may make us assume that they are rich with nectar and will attract all sorts of insects to feed on them. Nothing could be further from the truth.

A female Quedara monteithi monteithi feeding on the flower of the White Mussaenda

One classic example is roses. To us humans, not only do roses look attractive, the fragrance of a bouquet of roses appeals to most. Gardener enthusiasts of this colourful plant will probably be the best source of information as to whether butterflies visit roses for nectar. As it turns out, roses are apparently not attractive to butterflies and very rarely do we see butterflies visiting the colourful roses to feed on. Perhaps some experts can share their experience with us?

13. Hibiscus / China Rose (Hibiscus rosa-sinensis)

A female Common Birdwing feeding on the multi-layer flower of a Hibiscus hybrid

Back to our nectaring plants, and the first one in this article would be the China Rose or better known to most people as Hibiscus. Belonging to the Malvaceae family, the Hibiscus is characterized by a trumpet- shaped receptacle, five petals and a long pollen tube. The flower measures from 5 to 14 cm broad. Cultivars with flowers of many colours are used as ornamental plants. Some are double or have differently shaped petals.

A male Great Mormon feeding on the flower of the Hibiscus

Butterflies that visit the bright red Hibiscus flower to feed on its nectar are usually the larger species of the Papilionidae and some Pieridae. The physical characteristics of the flower itself, being large in size with an extended pollen tube would suggest that a butterfly trying to extract nectar from the flower would need a long proboscis to reach the nectar.

The Hibiscus is the national flower of Malaysia. Also called the Bunga Raya, the large and attractive flower won over several other candidates and was named the national flower in 1960. The plant is cultivated in many parks and gardens and its multiple cultivars that come in a whole variety of colours from reds and pinks to yellows and whites.

14. White Mussaenda (Mussaenda philippica 'Aurorae')

A Common Birdwing feeding on the orange flower of the White Mussaenda bush

This interesting plant from the Rubiaceae family grows as a large bush up to 3m tall and is cultivated in parks and gardens but may also grow wild in the forested nature reserves. The flowers of the Mussaenda are small, orange to yellow-orange and are tubular and star-shaped. They are arranged in small clusters known as corymbs and produce large, white, egg-shaped sepals that are up to 8 cm long. In many other species and cultivars, these attractive sepals can range from crimson red to pink and yellow.

A Great Helen feeding on the flower of the White Mussaenda

The tiny flowers of the White Mussaenda also attracts a variety of Hesperiidae to feed on it

The very small and sparse flowers of the Mussaenda attracts some butterflies in a very curious way. The long tubular shape of the flower requires an equally long proboscis to reach the nectar and it is for this reason that we have only observed butterflies that sport long proboscis feeding at this flower. Amongst the large Papilionidae, the Common Birdwing and Great Helen are regular feeders where the plant can be found, whilst the long-proboscis Hesperiidae have also been photographed on the Mussaenda flowers.

15. Thoroughwort (Eupatorium squamosum)

A male Blue Spotted Crow feeding on the florets of the Thoroughwort

This almost weed-like plant is not often found in the many species of flowering plants that are cultivated in our parks and gardens. However, where it grows, it is another Danainae "magnet" just like the False Dill or DogFennel (Eupatorium capillifolium) and Indian Heliotrope (Heliotropium indicum). These plants probably contain pyrrolizidine alkaloids which the Danainae need for their reproductive function and to maintain their distastefulness to predators.

A number of the Tigers and Crows are attracted to E. squamosum and cultivating it as part of the landscape palette in parks and gardens will probably add to the diversity of butterflies attracted to a landscaped butterfly garden. Curiously, we have not observed other species of butterflies feeding on the flowers of this plant.

16 . Straits or Singapore Rhododendron (Melastoma malabathricum)

A female Common Red Flash feeding on the flower of the Singapore Rhododendron

This plant from the Melastomaceae family is more well known as a butterfly attractant due to its ripened fruits, rather than for its flowers. When the plant is fruiting, the fermenting sugars in the fruits can attract a large variety of species of butterflies. The plant is also a caterpillar host plant for several species of butterflies.

The Satyrinaes are amongst the butterfly species that are observed on the flower of the Singapore Rhododendron

The attractive purple-pink flowers with bright yellow stamens have occasionally attracted various species of butterflies to feed on it. However, it is not a preferred nectaring plant, and there have been observations of large flowering bushes of the Singapore Rhododendron, but not a butterfly in sight! On the occasions that some species are seen on the flowers, it is usually in the early morning hours of the day. The Common Palmfly, Dark Brand Bush Brown, Malayan Eggfly, Malay Viscount, Malay Baron and Common Red Flash have been photographed on the flower of this plant.

17. Golden Net-Bush (Pseuderanthemum carruthersii)

A Dark Glassy Tiger on the flower of the Golden Net-Bush

A plant that has been cultivated in butterfly gardens, more to sustain the population of the Autumn Leaf (Doleschallia bisaltide bisaltide) as its alternative caterpillar host plant, the Golden Net-Bush's flowers sometimes attract butterflies to feed on it. The pretty white flowers with pink centres grow on long upright stalks and this is where some butterflies are observed to be attracted to feed on the flowers.

A Palm Bob feeding on the flower of the Golden Net-Bush

The Golden Net-Bush is an attractive shrub that adds to the colour and lushness of a landscaped garden - mainly due to its large light green net-veined leaves. However, due to the voraciousness of the Autumn Leaf's caterpillars, the bush may be defoliated very quickly if there are many caterpillars of this species on the plant.

18. White Weed (Ageratum conyzoides)

A Yellow Glassy Tiger feeding on the flower of the White Weed

This weed from the Asteraceae (Compositae) family is native to tropical Brazil. In Singapore, it appears as a wild flower in disturbed wasteland and cleared areas. It is considered an invasive weed in some countries and eradicated. Even in a landscaped butterfly garden, it is sometimes removed before it overwhelms other plants.

The mauve (light bluish purple) flowers are attractive to some species of butterflies. The Danainaes seem to like the flowers for nectar. Due to the small size of the flowers, they are well-suited for the Lycaenidae and some of these smaller sized butterflies have been seen to stop at the flowers for their daily food supply.

Text by Khew SK : Photos by Bob Cheong, Brian Goh, Khew SK and Loke PF

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