Favourite Nectaring Plants #9

Butterflies' Favourite Nectaring Plants #9
The Chinese Violet (Asystasia gangetica micrantha)


A Malay Lacewing feeds on the flower of the Chinese Violet

The feature plant in this article of our series on butterflies' favourite nectaring plants is the Chinese Violet. This tough widespread "weed" can be found in a number of habitats in Singapore, particularly in areas which have been cleared and awaiting development, or left to remain wild. It can be found growing in unkempt gardens to secondary forested areas to back-mangroves, usually as a low ground cover.

The Chinese Violet plant, with its delicated white and purple flowers

The Chinese Violet is a member of the family Acanthaceae, which features many butterfly host plants amongst the 2,500+ species in the family. The Chinese Violet is no exception, being a host plant for several Nymphalidae species like the Autumn Leaf, Blue Pansy and Great/Jacintha Eggfly. This species originated from sub-Saharan Africa, but has become naturalised in Asian countries like Singapore, where it grows rapidly in the hot humid climate.



This herbaceous plant spreads quickly and is able to climb vertically up to 1m or more, if supported. It does not appear to be particularly fussy about its substrate soils, and can appear in relatively harsh environments all across Singapore, although it prefers semi-shaded conditions to grow best. It roots easily when its stems and nodes come into contact with moist soil. Cuttings sprout white roots within 3-4 days if left in water, and the plant can easily be propagated this way.

Plant Biodata :
Family : Acanthaceae
Genus : Asystasia
Species : gangetica
Sub-species : micrantha
Synonyms : A. coromandeliana, A. intrusa, Justicia gangetica, Ruellia intrusa
Country/Region of Origin : Africa, Tropical regions
English Common Names : Chinese Violet, Common Asystasia, Creeping Foxglove, Ganges Primrose
Other Local Names : Ara Songsang, 赤边樱草, 十万错花


The paler green underside of the Chinese Violet leaf

The opposite pairs of leaves occur at right angle to each other

The green leaves are simple, opposite and decussate (successive pairs of opposite leaves occur at right angle to each other). Each leaf is ovate or heart-shaped, sparsely hairy, smooth-edged and ranges between 3 to 7.5cm long. The plant grows upright on squarish stems that have ribs and short hook-like hairs.


The flower of the Chinese Violet with the purple lower lip

The flowers are in small, one-sided racemes at the stem tips, with the flowers at the bottom of the raceme opening first. Flowers of the Chinese Violet are small and tubular, each up to 3.5cm long. There are usually 6 to 10 flowers borne on each raceme. The calyx has 5 rounded lobes, purple, vein-ridged markings on the lower lip, and 4 stamens. This species is free-flowering throughout the year. These bisexual flowers attract insects including various species of butterflies to act as pollinators in the reproduction process.

Buds, flowers and fruits of the Chinese Violet

Explosively dehiscent fruits, which come in club-shaped capsules, are initially green, but becomes brown and dry after dehiscence (3.6 cm long). The fruit resembles an upside down cello and contains 4 whitish to brownish black, circular seeds which are flattened and beaked (5 mm long, 1 mm thick). Fruits contain 3 mm-long hooks which help to propel the seeds further away from the plant during explosive dehiscence.


Ripened fruit and seeds of the Chinese Violet

In some parts of Africa, the leaves are eaten as a vegetable and used as an herbal remedy in traditional African medicine. The leaves are used in many parts of Nigeria as a traditional African medicine for the management of asthma. In Australia, this species is considered invasive and a serious threat to native ecosystems, and sightings of the Chinese Violet have to be reported to the authorities.


Flower of the Chinese Violet, where a spider tries to remain 'hidden' to wait for unwary prey coming to feed on the flower

Besides being host plant to several butterfly species, the white/violet flowers of the Chinese Violet is rather attractive to the adult butterflies. The 'universality' of the flower of this plant to butterflies is interesting, as we have seen species from 5 out of the 6 butterfly families feeding on it. With the exception of Riodinidae, representative species from Papilionidae, Pieridae, Nymphalidae, Lycaenidae and Hesperiidae have been regularly observed sipping nectar from the flowers of the Chinese Violet.



The bigger swallowtails also like to feed on the flower of the Chinese Violet

Of the Papilionidae, we have seen these larger swallowtails fluttering at the white/violet flowers of the Chinese Violet with their long proboscis extended deep into the flower. Species observed are the Common Mormon, Lime Butterfly, Common Mime, and even a Blue Helen, although it is often difficult to photograph these species moving rapidly from flower to flower with their forewings constantly flapping in the usual Papilionidae fashion.




The Grass Yellows feeding on the flower of the Chinese Violet.  Note how they have to poke their heads deep into the flower to get at the nectar within the flower.

Amongst the Pieridae, the Grass Yellows (Eurema spp.) are most often seen stopping and pushing their heads deep into the flower of the Chinese Violet. Perhaps the shorter proboscis of the smaller Grass Yellows cannot extend far enough into the flower to reach the nectar, so they need to push their heads further in to get at their liquid diet.





The Tigers and Plain Lacewing reaching into the flower to get at the nectar

The large Danainaes and Nymphalinaes from the family Nymphalidae are quite regularly spotted to feed on the nectar from the Chinese Violet flowers. As with the Pieridae, even these larger butterflies are observed to push their heads deep into the flower (often giving a "headless" butterfly shot) when their heads are out of sight whilst they feed at the flower. Species featured here include the Common Tiger, Dark Glassy Tiger, Plain Lacewing and Malay Lacewing are some examples of the Nymphalidae that feed on the Chinese Violet flowers.




The diminutive Lycaenidae are also attracted to the flower of the Chinese Violet. Being small butterflies with fine proboscis, the Lycaenidae also have to reach far into the flower to get at the nectar.





Skippers love the flower of the Chinese Violet

In the early morning hours, look for the Hesperiidae (Skippers) zipping amongst the low bushes of the Chinese Violet, reaching far into the flower with their long proboscis to feed on the nectar. From the photo records of ButterflyCircle members, it appears that a larger number of different species of Hesperiidae have been observed feeding on the flower of the Chinese Violet than any other family.



Despite being an unwanted weed found in wastelands, unkempt patches of greenery and cleared patches of sites awaiting redevelopment, the Chinese Violet is a valuable plant that is used for sustenance by Singapore's butterflies. It is a caterpillar host plant for at least 3 species of butterflies, and a nectaring plant for a good variety of species of butterflies.



So when you are out butterfly-watching, do keep a lookout for these 'white dots' amongst the low green shrubbery and ground cover - these are the pretty flowers of the Chinese Violet. Watch for the butterflies that feed on these white/violet flowers and add on to the list of species that you can see here, that use the Chinese Violet flower as a nectar source.

Text by Khew SK : Photos by Sunny Chir, Chng CK, Federick Ho, Khew SK, Loke PF, Horace Tan and Mark Wong

Butterfly of the Month - March 2017

Butterfly of the Month - March 2017
The White Banded Awl (Hasora taminatus malayana)

March seemed to have come and (almost) gone in a flash. This is the last Saturday of the month, and I almost forgot to showcase our feature butterfly for this month on the blog! March seemed like a short month, after all the Lunar New Year festivities and holidays in February came to an end, and everyone settled back to work.

For homeowners who still hold outstanding loans, the US Fed hike in March caused a bit of concern for these SIBOR-linked borrowers. With two more impending rate hikes under the Trump administration in the coming quarters, the days of low-interest loans may be numbered. It will be interesting to see how the global economy changes in these turbulent times. A friend recently shared that business is booming back in the US, and she was swamped with work piling up for the months to come.

A White Banded Awl feeding on the flower of Ixora (top) and puddling on damp concrete (bottom)

This month, I tried the GrabCar app for the first time - ironically, back in my hometown in Penang where I was visiting my parents. This transportation platform, like the more ubiquitous Uber, is one of the disruptive technologies that has radically changed the face of public transportation. I must say that my maiden experience with Grab was largely positive and hassle-free. I merely clicked on the app, set my destination, and the designated car details and driver were sent to me.

Other than a small hitch where the driver missed my pickup location (and I could see on my smartphone tracking his car, that he went off to an adjacent road), the car arrived in about 10 minutes flat from the time I clicked 'confirm booking' on my smartphone. The driver was a Malaysian Indian who was in between jobs. He was polite and very knowledgeable about current affairs and recent news in Malaysia and Penang. All in all, the ride was pleasant and I reached my destination in good time. The best thing was that Grab's fixed fare was only 55% of what a normal taxi would have cost!

Back home in Singapore, I took possession of my new "toy" - a DJI Mavic Pro.  This new high-tech drone (or some prefer to call it 'flying camera') is pretty awesome technology. My first impression of this Chinese-designed-and-manufactured drone was that the finish and quality of the product exceeded all expectations. The amount of technology in the hardware and software is mind-boggling and I am still discovering new things about the drone.

Unfortunately, Singapore is a small island and the number of no-fly-zones and regulatory requirements limit the number of places that one can legally fly the drone. Hopefully, some of these regulations can be relaxed a bit so that responsible recreational drone pilots can help to document Singapore in a totally different perspective and for a variety of useful applications from urban planning to building inspections.

This month, we feature a pretty skipper, the White Banded Awl (Hasora taminatus malayana). This species belongs to the subfamily Coeliadinae of the family Hesperiidae. The subfamily features a number of robust, fast-flying, fat-bodied butterflies commonly referred to as the Awls or Awlets. Many of the species are crepuscular, often seen on the wing in the early hours of the morning and late in the evenings just before dusk.

A typical pose of the White Banded Awl, playing hide-and-seek from under the shelter of a leaf

The White Banded Awl is a forest-dependent species, usually found in the nature reserves in well-shaded localities. It has a habit of flying rapidly and is often observed to settle on the underside of a leaf with its wings folded upright. Once disturbed, it takes off at high speed to search for another hiding place to rest on the underside of a leaf again.

A pristine White Banded Awl puddling on damp concrete

The species is also known to puddle on bird droppings and sometimes found puddling on damp building structures (concrete or wood) in the early morning hours. Occasionally, it is also found feeding off sap on damp tree trunks with its long and distinctive proboscis. When certain forest trees flower, e.g. Syzygium spp. the White Banded Awl may be seen zipping rapidly amongst the flowers and stopping to feed on the nectar.

The male White Banded Awl is dark velvety brown above and unmarked, whilst the female has small pale yellow post-discal spots on the forewings. The underside is pale brown with the wing bases strongly suffused with iridescent bluish-green scales. There is a narrow but distinct white post-discal band on the hindwing. In a side light, the bluish sheen makes it an attractive looking skipper and distinctively different from the majority of brown and sombre looking butterflies in the family.

The White Banded Awl's 'baby photo'

The caterpillar of the White Banded Awl feeds on Derris trifoliata (Sea Derris), a host plant that it shares with at least two other species of butterflies in Singapore.

Text by Khew SK : Photos by Sunny Chir, Khew SK, Koh CH, Loke PF, Nelson Ong, Jonathan Soong and Horace Tan

Life History of the Purple Duke v2.0

Life History of the Purple Duke (Eulaceura osteria kumana )

Butterfly Biodata:
Genus: Eulaceura Butler, 1872
Species: osteria Westwood, 1850
Subspecies: kumana Fruhstorfer, 1913
Wingspan of Adult Butterfly: 50-70mm
Caterpillar Local Host Plant: Gironniera nervosa (Ulmaceae, common name: Common Rough Laurel).

A male Purple Duke taking nectar from ripened fruits of the Singapore Rhododendron.

Another male Purple Duke taking nectar from ripened fruits of the Singapore Rhododendron.

A sunbathing male Purple Duke giving a view of its upperside.

Physical Description of Adult Butterfly:

On the upperside, the male is purple brown with a prominent white discal band spanning both wings, broadening towards the tornal margin of the hindwing. The female is dull ochreous brown with obscure whitish markings on both wings. On the underside, the wings are tinged purplish blue in a side light, more so in the male. The white discal band spanning both wings are featured in both sexes, but in the female it is much thinner in the hindwing.

A female Purple Duke taking nectar from Sygyzium flowers.

A sunbathing female Purple Duke giving a view of its upperside.

The upperside view of a female Purple Duke.

Field Observations of Butterfly Behaviour:

Purple Duke is common in Singapore, but its presence is restricted to the nature reserve where its host plant occur in abundance. The adults have a habit of flying rapidly in low bushes and settling on the underside of leaves. In the field, the female can be easily mistaken to be a female of Euthalia species. Both sexes have the habit of puddling and taking nectar from ripened fruits and flowers.

A puddling male Purple Duke.

A male Purple Duke puddling in shallow drain in the northern catchment reserve.

A puddling female Purple duke.

A female Purple Duke taking nectar from ripened fruits of the Singapore Rhododendron.

Early Stages:

Only one local host plant is recorded for the Purple Duke. The plant, Gironniera nervosa (Common Rough Laurel), is common in the central catchment reserve. The caterpillars of the Purple Duke feed on leaves of the host plant, with the caterpillar in all but the final instar adopting the habit of eating the leaf lamina between secondary veins.

Local host plant: Gironniera nervosa (Common Rough Laurel).

Mostly underside view of leaves of Common Rough Laurel. Three caterpillars of the
Purple Duke can be seen on three separate leaves.

The eggs of the Purple Duke are laid singly on the leaf of the host plant, typically on the underside of the leaf. Each pale milky white egg is globular with a diameter of about 1.1mm. A number of longitudinal ridges are present. Each egg takes about 3-3.5 days to hatch. The young caterpillar nibbles away a portion of the egg shell to emerge, leaving the remnant uneaten.

Two views of an egg of the Purple Duke, 1-1.5 days old.

Two views of a mature egg of the Purple Duke, with portion of the egg shell eaten in the right panel.

With a length of about 3.5mm, the newly hatched is pale beige brown in both its body and head. There are a number of narrow whitish bands running length-wise on the body surface. The caterpillar also features two backward-pointing black-tipped anal processes.

Two views of a newly hatched caterpillar, length: 3.5mm.

As the 1st instar caterpillar grows up to a length of about 7-7.5mm, the body takes on a strong green undertone. After about 2.5-3 days in the 1st instar, the caterpillar moults to the next instar.

Two views of a 1st instar caterpillar, length: 7.3mm.

Two views of a late 1st instar caterpillar, dormant prior to its moult, length: 6.8mm.

The 2nd instar caterpillar has a few changes in its appearance as compared to the 1st instar caterpillar. Now the body ground colour is green, and the longitudinal bands are whitish to yellowish. The head capsule is black with two large cephalic horns, featuring side branches on the lateral peripherals as well as on the cephalic horns. This instar lasts about 4-5 days with the body length reaching up to 11mm before the next moult.

Two views of a 2nd instar caterpillar, newly moulted, the head capsule yet to turn black.

Two views of a 2nd instar caterpillar, length: 9.8mm.

Two views of a 2nd instar caterpillar, dormant prior to its moult.

The 3rd instar caterpillar resembles the 2nd instar caterpillar closely. The main change occurs in the head capsule where the black lateral processes and cephalic horns are proportionately longer. The head is mostly pale brownish. The many longitudinal bands in the earlier instar give way to a checkerboard pattern of yellow and green. The 3rd instar takes about 4-5 days to complete with the body length reaching up to 16-17mm.

Two views of a 3rd instar caterpillar, newly moulted.

Two views of a 3rd instar caterpillar, length: 15.2mm.

Two views of a late 3rd instar caterpillar, dormant prior to its moult, length: 15.7mm.

A late 3rd instar caterpillar found on a leaf in the field.

The 4th instar caterpillar resembles the 3rd instar caterpillar with the main change occurring again in the head capsule. Now the "face" is whitish green and the body appears to be predominantly green and adorned with numerous tiny yellowish spots. It has two prominent, pale whitish to yellowish dorso-lateral bands. This penultimate instar lasts about 7 to 10 days with body length reaching about 26-27mm.

Head of Purple Duke caterpillars. Left: 3rd instar; Right: 4th instar.

Two views of a 4th instar caterpillar, newly moulted.

Two views of a 4th instar caterpillar, late in this stage, length: 26mm.

Two views of a late L4 caterpillar, dormant prior to its moult, length: 25.5mm.

The next moult brings the caterpillar to its 5th and final instar. Now the head capsule is mostly whitish green and the cephalic horns pale reddish brown. The two pointed anal processes are greenish to pale reddish brown in colour.

Two views of a newly moulted 5th instar caterpillar .

Two views of a 5th instar caterpillar, length: 35mm.

A 5th instar caterpillar sighted on the underside of a leaf in the southern catchment reserve.

The 5th instar lasts about 11-13 days, and the body length reaches up to 45-47mm. In this instar, the caterpillar does not avoid secondary veins of the leaf when feeding.

Two views of a 5th instar caterpillar,late in this stage, length: 49mm.

A 5th instar caterpillar sighted in the northern catchment reserve.

Toward the end of the 5th instar, the body gradually shortens in length with the body base colour turning to translucent green. Eventually the caterpillar comes to rest on a chosen spot on the underside of a leaf. Here it stays dormant for a while before spinning a silk pad and anchoring its anal claspers to it. It then becomes an pre-pupatory larva in this upside-down pose.

An early pre-pupatory larva of the Purple Duke, length: 35-38mm.

A pre-pupatory larva of the Purple Duke.

Pupation takes place about 0.5-1 day later. The pupa suspends itself with a cremastral attachment to the silk pad on the substrate. The pupa is mainly green mottled with cryptic yellowish markings. Each pupa has a pair of short cephalic horns. The body has a slight keeled appearance as it broadens and tapers to a yellowish ridge on the dorsum. Length of pupae: 24-26mm.

Two views of a pupa of the Purple Duke.

After 6 days of development, the pupa turns yellowish brown in the abdomen and black in the wing pads as the development within the pupal case comes to an end. The next day the adult butterfly emerges from the pupal case.

Two views of a mature pupa of the Purple Duke.

A female Purple Duke emerges from its pupal case.

A newly eclosed female Purple Duke clinging on its pupal case.

A newly eclosed male Purple Duke resting near its pupal case.

References:

• [C&P4] The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, Malayan Nature Society, 1992.
• Butterflies of Thailand, Pisuth Ek-Amnuay, 2nd Edition, 2012
• A Field Guide to the Butterflies of Singapore, Khew S.K., Ink On Paper Communications, 2nd Edition, 2015.

Text by Horace Tan, Photos by Jonathan Soong, Benedict Tay, Huang CJ, Nelson Ong, Sunny Chir, Khew SK and Horace Tan