15 October 2017

Favourite Nectaring Plants #14

Butterflies' Favourite Nectaring Plants #14
The Golden Dewdrop (Duranta erecta)

A male Plain Tiger feeding on the attractive purple flowers of the Golden Dewdrop

Our fourteenth butterfly nectaring plant in this series is an attractive flowering bush, the Golden Dewdrop (Duranta erecta). This plant, with its lush green leaves, purple flowers and golden yellow fruits, is often cultivated in many parks and gardens in Singapore as hedge or as a colourful accent to the horticultural palette in landscape design.

The Golden Dewdrop is certainly not considered a "weed" or a wildflower, unlike the last couple of plants featured in our Butterflies' Favourite Nectaring plants series of articles. Often preferred by gardeners for its showy terminal clusters of purple flowers - known as racemes, the Golden Dewdrop is also unique in that its clusters of yellow globular fruits are also featured as part of the aesthetic value of the plant.

A flowering Golden Dewdrop bush at an urban garden

The genus name of this plant is in honour of Castore Durante da Gualdo, a fifteenth-century physician, botanist and poet of the Italian Renaissance. Amongst Castore Durante's major botanical works were the Herbario Nuovo, published in 1585, which is a description of medicinal plants from Europe and the Indies (East and West) and Il Tesoro della Sanità, published in 1586, is a collection of folk-medicine remedies for the family, with practical rules for hygiene and dietary suggestions.

The specific epithet erecta means "upright" in Latin. The plant is also known as D. repens, from the Latin for "creeping". The latter name was originally used to identify smaller-leaved varieties of the species. In some literature, the Golden Dewdrop is also called D. plumieri. However, in contemporary botanical references, the name Duranta erecta has been the most widely accepted taxonomic name for this plant.

It is considered an exotic plant in Singapore, but is common and found in many public and private gardens. Interestingly, the Golden Dewdrop is registered as an invasive weed by many councils of Australia. It is considered a fast growing weed that is spread by birds from domestic areas to natural reserves. It was introduced and marketed as a hedge plant by commercial nurseries in Australia. Many people now fight to keep this thorny pest under control. It is highly ranked in the most invasive weeds in Australia.

Plant Biodata:
Family: Verbenaceae
Synonyms:Duranta repens, D. plumieri
Country/Region of Origin: Tropical America
English Common Names: Golden Dew-Drop, Lilac-flowered Golden Dewdrop, Pigeon Berry, Sky Flower, Brazilian Sky Flower
Other Local Names: Kachang Puteh, 金露花, 假连翘, 小本苦林盘

The Golden Dewdrop is a sprawling evergreen shrub and can even grow into a small tree of up to 6 m tall and can spread to an equal width. The shrub is usually well-leafed and used as boundary hedges or even for topiary in themed gardens. A mature plant has thick woody stems growing erect from the ground but new leaves grow prolifically and spreads rapidly. There are a wide variety of cultivars available, including 'alba', 'aurea', 'Aussie Gold', 'Gold Mound', 'Geisha Girl', 'sapphire showers', and 'variegata'.

The serrated-edged mature leaves of the Golden Dewdrop

The leaves are light green, elliptic to ovate, opposite with serrate or entire leave margins, and grow up to 7.5 cm long and 3.5 cm broad, with a 1.5 cm petiole. The leaves are soft when immature, but becomes a darker shade of green with thicker lamina when mature. Foliar venation is net-veined and each leaf ends in a sharp tip.

Axillary thorns along the stems.  Danger! Keep away from these sharp needle-like thorns!

Mature specimens possess axillary thorns, which are often absent on younger specimens. These thin, needle-like thorns are particularly sharp, and a photographer who is unaware of this "vicious" weapon on the plant, can suffer some particularly painful encounters. It should also be highlighted that the leaves of the plant is toxic, and combined with the thorns, it is best to be cautious around this plant.

Flower buds and flowers of the Golden Dewdrop

The bisexual flowers are light-blue or lavender, produced in tight clusters located on terminal and axillary stems referred to as racemes. The flowers bloom almost all year long. The plant grows best in full sun, where it blooms abundantly, but also tolerates semi-shaded locations. It should be pruned regularly to encourage new growth.

Fruit cluster of the Golden Dewdrop

The fruit of the Golden Dewdrop is a small globose yellow or orange berry, up to 11 mm in diameter and containing several seeds. These berries of the plant contains toxins, and are confirmed to have killed children, dogs and cats. However, it appears that some birds eat the fruit without ill effects, and indeed the seeds are dispersed by birds.

The golden yellow fruit of the Golden Dewdrop which probably gave its common name to the plant.  Pretty, but poisonous!

The berries may look pretty and almost delicious, but they are certainly to be avoided. Phytochemical analysis of fruits yielded alkaloids, glycoside, saponins, and tannins and poisoning is consistent with alkaloid-type reactions. When the fruits ripen, they turn black and shriveled. The seeds are contained within the fruit and are usually dispersed by birds that ingest them.

A selection of Swallowtails feeding on the flowers of the Golden Dewdrop

Now we move over to our butterflies. The Golden Dewdrop is a reasonably attractive butterfly nectaring plant, particularly in the urban parks and gardens. When the purple flowers are in full bloom, and where the garden is butterfly-friendly, many species are usually attracted to the flowers to feed. The larger Papilionidae love the flowers, and amongst the urban dwellers, we have seen the Common Mormon, Common Rose, Lime Butterfly, Common Mime and even the speedy Common Bluebottle feeding on the Golden Dewdrop flowers.

Some Pieridae butterfly species that like the Golden Dewdrop flowers

The Pieridaes also like the flowers for nectar, and the fast flyers amongst the Emigrants are often seen stopping to feed on the purple flowers. Striped Albatross is also a frequent visitor - both males and females, and the ubiquitous Common Grass Yellow. The high-flying Painted Jezebel drops down from its aerial acrobatics to refuel at the Golden Dewdrop flowers.

Many species of Crows and Tigers are attracted to the flowers of the Golden Dewdrop

The large Crows and Tigers are regularly seen feeding on the Golden Dewdrop flowers. Amongst those city residents seen are the Plain and Common Tigers, Dark and Blue Glassy Tigers and even the odd King Crow and Striped Blue Crow. Up north in Malaysia, the Dark Blue Tiger and Yellow Glassy Tiger (both of which are recorded as seasonal migrants in Singapore) have also been observed at the purple flowers of this plant.

Some Nymphalid butterflies that love the purple flowers of the Golden Dewdrop

The urbanite Nymphalidaes also take to the flowers of the Golden Dewdrop, and amongst them, we have observed the Tawny Coster, Blue/Peacock/Chocolate Pansy and Leopard at the flowers of this plant.

Amongst the Lycaenidae, I have only seen the Grass Blues stopping to feed at the Golden Dewdrop flowers, although it is a mystery why more urban species like the Common Tit, Peacock Royal and Cycad Blue, all of which have been seen flying in the vicinity of the plant, do not quite prefer the flowers as a nectaring source. Perhaps other observers who have photograph these Lycaenidae feeding on the purple flowers can share your encounters here.

Small skippers that feed on the flowers of the Golden Dewdrop

Finally, amongst the skippers found in our local parks and gardens, the most common species found at the purple flowers of the Golden Dewdrop is the Small Branded Swift. Other species observed feeding are the Lesser Dart, Palm Bob and one or two of the Awls.

So the next time you are out enjoying yourself at a community garden or a butterfly garden where the Golden Dewdrop is cultivated, do keep a keen eye on the pretty purple flowers of this plant and watch out for the butterflies that stop and feed at this favourite nectaring source.

Text by Khew SK : Photos by Chng CK, Foo JL, Huang CJ, Khew SK, Lee KH, Loke PF and Cindy Yeo.

Butterflies' Favourite Nectaring Plant #13 : Coat Buttons

07 October 2017

Butterfly of the Month - October 2017

Butterfly of the Month - October 2017
The Pale Mottle (Logania marmorata damis)

A Pale Mottle perches on the top of a leaf to rest

We are into the 10th month of 2017 now, and the cooler temperatures and wetter weather of the year end monsoons are upon us. Those countries in the northern hemisphere prepare for autumn and the coming of winter. A recent trip to Shanghai and Suzhou was met with heavy rain and I had experienced for the first time, what a 5-hour delay on an SIA flight was like. Probably nothing as far as flight delays are concerned, but a most unproductive day sitting on the plane and watching movies with glazed eyes.

In Singapore, the wetter weather saw a drop in butterfly activity in the majority of our favourite hunting grounds. Butterfly photography outings over the past couple of weeks were largely unproductive (besides the high chance of getting soaked in one of our tropical thunderstorms). But cooler days (and nights) were a welcome relief from the hot humid days in the earlier months of the year.

Just in the first week of October, another senseless shooting occurred in Las Vegas in the US. Despite calls for gun control, very little has been done, and how many more innocent lives must be lost before someone will say enough is enough? A gunman opened fire from a hotel overlooking a country music concert in Las Vegas, killing at least 58 people and wounding more than 489 others in the deadliest shooting in modern U.S. history.

It is quite surreal as one views the many videos that are on the internet. It is a random shooting and you wonder who a bullet finds in that crowd, and who a bullet misses. Life is fragile indeed. Singapore is fortunate to have strict gun control laws and it is highly unlikely that a mass shooting like this can happen, even though there are no guarantees that there are determined madmen around who try to beat the system and laws.

Around the region, another natural disaster in the making is the potential eruption of the Indonesian active volcano, Mount Agung in Bali. Mount Agung has reached a "critical" stage with 500 tremors shaking the area a day, according to Indonesia's National Disaster Management Agency. According to news reports, more than 134,000 people have fled the area surrounding the Mount Agung, fearing an imminent eruption. Despite the local tourism authorities assuring tourists heading for Bali that it is still "safe", it is inevitable that the tourism numbers will drop significantly as people will avoid the area.

Pale Mottles stopping to feed on the secretions of other insects amongst the ants

Again, our little island of Singapore is blessed in that we are free of typhoons, earthquakes, erupting volcanoes and other natural disasters that we often see around the world. There have been tremors felt in parts of Singapore whenever an earthquake occurs in neighbouring Indonesia, but nothing serious has affected the island in recent history.

A mating pair of Pale Mottles

Moving away from disasters, both natural and man-made, we turn our attention to our Butterfly of the Month for October 2017 - the Pale Mottle (Logania marmorata damis). This tiny butterfly belongs to the interesting sub-family of butterflies called Miletinae or collectively called the Harvesters. The caterpillars of this subfamily are considered "carnivorous", as their caterpillars feed on coccids, mealy bugs, aphids and other insects.

A typical perching Pale Mottle with its forelegs pulled in tightly to its thorax

The Pale Mottle is not considered a rare species in Singapore, as they are widespread and can occur anywhere where their caterpillar food source is available on a wide variety of plants. The adult butterfly flies with a restless erratic flight, often remaining in flight for long periods of time without stopping to rest.

A Pale Mottle feeding on the secretions of mealy bugs that are tended by ants

With a wingspan of only about 20mm, the Pale Mottle frequents shaded areas in forested localities over a wide variety of habitats. It can even be found in urban gardens and parks. As it flutters around the shrubbery, one can often expect it to land on a congregation of ants tending to aphids or other similar 'pests' that exude sweet secretions.

A Pale Mottle amongst ants - what makes the butterfly 'invisible' to these predators?

The Pale Mottle is often observed to feed on the secretions of these insects where the attending ants curiously leave the butterfly alone. Are there any natural 'cloaking devices' that the butterfly possesses that make it invisible to the ants? Or the ants instinctively know that the butterfly is not a threat and leave it alone? A good subject for a research topic!

The upperside of the Pale Mottle is a bluish grey with a broad black apical border. The hindwing is brown in the male, but features streaks of grey in the female.  The underside is cryptically marked and mottled with dark brown, buff and light orange striations, giving the butterfly a marbled appearance.

Although most encounters of this butterfly are of individuals fluttering around trees and shrubs, mating pairs of the Pale Mottle are regularly seen - as can be observed by the frequent number of photographs of a pair of the butterfly 'doing their thing'. Mating pairs are usually more docile and perch stationary, making it much easier for a photographer to shoot them.

A Pale Mottle feeds on mealy bug secretions amongst the 'farmer' ants

When they locate a colony of ants tending to aphids, mealy bugs or coccids, the Pale Mottle tends to flutter around the plant stem where the ants can be found, often landing right in the midst of the ants and aphids/mealy bugs and then joining the ants that are feeding on the secretions of these insects. At times, a female may lay her eggs beside the aphids/mealy bugs, where, upon hatching, proceed to feed on the other insects!

At other times, an individual stops to rest on a leaf tip, making it an easy subject to hunt down and photograph. However, its diminutive size makes it a challenging macro subject to shoot when trying to deal with the shallow depth of field to ensure all parts of the butterfly are in sharp focus. Its preference to rest in deep shade also makes photography in low light conditions necessary.

A not-so-common shot of a Pale Mottle with all six legs fully extended

The Pale Mottle features banded legs, black at the joints. antennae are long and curved at the tips. Species in the subfamily are also characterised by prominent palpi, projecting way beyond the head and eyes of the butterfly. Even though the species has six fully-developed legs, individuals usually perch on four legs, and hold their forelegs close to the thorax. Only on rare occasions where an individual is seen perching with all six legs fully extended.

As mentioned earlier, the caterpillars of the Pale Mottle feed on other living creatures like coccids, mealy bugs and aphids, making them carnivores, unlike most caterpillars of Lepidoptera, which largely feed only on plant material.

Text by Khew SK : Photos by James Chia, Brian Goh, Huang CJ, Khew SK, Koh CH, Loke PF, Bobby Mun, Nelson Ong, Michael Soh, Jonathan Soong, Bene Tay and Anthony Wong.

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