30 April 2016

Larval Host Plant for Butterflies: Malayan Mistletoe

Butterflies' Larval Host Plants #9
The Malayan Mistletoe (Dendrophthoe pentandra)

Malayan Mistletoe on Polyathia longifolia (False Ashoka) in Upper Seletar Park.

This 9th instalment of our Butterflies' Larval Host Plants series features Dendrophthoe pentandra (Malayan Mistletoe), a member of Loranthaceae which is a family of flowering plants containing 75 genera and about 1,000 species, many of which are hemiparasites (parasitic plants which derive water/nutrients from the hosts and are photosynthetic themselves). The Malayan Mistletoe is a stem hemiparsite as it attaches itself to the stem/branch of its hosts.

Malayan Mistletoe on a Batoko Plum plant along Dairy Farm Road.

The Malayan Mistletoe is the commonest of the 10 parasitic plant species extant in Singapore. Many trees and shrubs (of many species across multiple families) growing in urban areas, residential estates, parks and gardens, wastelands, wetland and nature reserves have been observed to be parasited by it.

Malayan Mistletoe on a Mango tree in Mount Faber Park.

Plant Biodata :
Family : Loranthaceae
Genus : Dendrophthoe
Species : pentandra
Synonyms : Loranthus pentandrus, Amylotheca pentandrus.
Country/Region of Origin :  Eastern India,  Indochina, southern China and Malesia
English Common Name : Malayan Mistletoe
Other Local Names :  五蕊寄生, 乌榄寄生
Larval Host for Butterfly Species: Delias hyparete metarete (Painted Jezebel), Tajuria cippus maxentius (Peacock Royal), Euthalia adonia pinwilli (Green Baron), Jacoona anasuja anasuja (Great Imperial).

Malayan Mistletoe on a cultivated plant in the NUS campus.

The Malayan Mistletoe is an epiphytic shrub up to 2m tall. Branches/stems are brownish to grayish with lenticels scattered on the surface. The leaves are variable in shapes (lanceolate to elliptic or suborbicular) and sizes (5-15cm in length, 2.5-10cm in width). Young shoots are covered with minute hair (pubescent) and young leaves are initially reddish. Mature leaves are green, thick and leathery.

Young leaves of the Malayan Mistletoe.

A branch of the Malayan Mistletoe bearing maturing leaves and several flower buds.

Close-up view of a mature leaf of the Malayan Mistletoe.

Fruits of the Malayan Mistletoe are typically dispersed by birds. When the beak of a bird grips on a fruit, the skin of the ripened fruit comes off easily, exposing the sticky coat of the single seed. The sticky seed will either be stuck to the bird's beak, or be eaten by the bird and passes through its digestive system. Either way, the seed could then be transported to another plant visited by the bird. Sometimes, the sticky seed would fall off and land on other branches of the same plant as the bird grips on the fruit. In all cases, the sticky coat of the seed allows it to easily adhere to the stem/branch surface of the host plant it lands on.

A young seedling of the Malayan Mistletoe. Note the ripened seed attaching to the stem of the host plant.

Two young seedlings of the Malayan Mistletoe on a branch of Yellow Cow Wood, with a third attached seed (to the right of the younger seedling) yet to germinate.

As with all stem hemiparasites, the Malayan Mistletoe has specialized roots called haustoria which penetrate into the host's tissues and connect to the xylem/phloem of the host. This allows it to draw water and non-organic nutrients from the host. The haustoria of the Malayan Mistletoe are much enlarged with a ball-like appearance.

The primary hautorium of one Malayan Mistletoe plant.

The hautorium of another Malayan Mistletoe plant with side stems trailing along the host's branch.

Flowers of the Malayan Mistletoe are bisexual and occur in racemes, each of which bearing 3 to 10 flowers. Each flower is about 1.5 to 2cm long. The petals are orange and the basal half of the corolla is slightly inflated.

Flower buds of the Malayan Mistletoe.

A raceme of flowers of the Malayan Mistletoer.

A closer view of flowers of the Malayan Mistletoe.

Fruits are small, 8 to 10mm long, yellowish green to pink in colour when young and reddish when ripened.

A branch of the Malayan Mistletoe bearing developing fruits.

Maturing fruits of the Malayan Mistletoe.

Close-up view of a fruit of the Malayan Mistletoe.

In Singapore, the Malayan Mistletoe serves as the larval host plant for four butterfly species in three families: Painted Jezebel, Peacock Royal, Great Imperial and Green Baron. The first is a Pierid, the second and third are lycaenid and the last is a limenitid.

A Painted Jezebel.

A Peacock Royal.

A Great Imperial.

A Green Baron.

Eggs of the Painted Jezebel are laid in a loose cluster on the underside of a leaf of the Malayan Mistletoe, while those of the Peacock Royal and Great Imperial are laid on a young shoot or the underside of a young leaf. Eggs of the Green Baron are laid singly on the upperside of a mature leaf.

Eggs of the Peacock Royal laid on a young shhot of the Malayan Mistletoe.

A cluster of eggs of the Painted Jezebel laid on a leaf of the Malayan Mistletoe.

Caterpillars of the Painted Jezebel, Peacock Royal and Great Imperial feed on young and maturing leaves of the Malayan Mistletoe, typically on the leaf underside. In contrast caterpillars of the Green Baron feed on mature leaves of the Malayan Mistletoe. Caterpillars of the Painted Jezebel are gregarious.

A group of late 1st instar caterpillars of the Painted Jezebel feeding on the underside of a leaf of the Malayan Mistletoe in Upper Pierce Reservoir Park.

A group of five late instar caterpillars of the Painted Jezebel in Mount Faber Park.

Another view of the same group of caterpillars feeding together at the leaf edge.

A final instar caterpillar of the Peacock Royal feeding on a leaf of the Malayan Mistletoe in the Japanese Garden.

A final instar caterpillar of the Great Imperial feeding on a leaf of the Malayan Mistletoe.

A penultimate instar caterpillar of the Green Baron resting on a leaf of the Malayan Mistletoe.

Text and Photos by Horace Tan.

24 April 2016

The Rise & Fall of a Butterfly Garden

The Rise and Fall of a Butterfly Garden
Alexandra Hospital Butterfly Trail

Entrance to the Alexandra Hospital Butterfly Trail in Apr 2016

It was a long while back in 2001 when the then-CEO of Alexandra Hospital, Liak Teng Lit mooted the idea of bringing back biodiversity into the grounds of the hospital. Fifteen years ago, when biophilic design was still relatively unknown, Liak and his team pioneered the use of greenery and nature to augment the process of healthcare rehabilitation and healing of patients at Alexandra Hospital. Lush greenery and biodiversity, the AH team opined, gave the hospital its cutting edge 'brand' amongst Singapore's restructured public sector hospitals.

Alexandra Hospital Butterfly Trail in 2008

It was also at that time when the planning and design of the new Khoo Teck Puat Hospital at Yishun was still in its early stages, and already, the signature biophilic design and building+greenery+biodiversity strategy was very much a part of the design concept. 

Alexandra Hospital Butterfly Trail in 2008

The Butterfly Trail at Alexandra Hospital started at an open valley adjacent to Alexandra Road, and through which a narrow stormwater drain ran. Over the years, this green patch was nurtured with tender loving care by retired occupational therapist Rosalind Tan and her small team of 3 gardeners (who also tended to the entire 11Ha site on which Alexandra Hospital sat). Nectaring plants and caterpillar host plants were procured and cultivated at the site, and precast concrete panels added to create a walkway within the Butterfly Trail. A DIY irrigation system was even added on to keep the garden well-watered.

A total of 102 species of butterflies were recorded at AH Butterfly Trail in 2008

Up to 102 species were spotted at the AH Butterfly Trail when the checklist was last updated in Nov 2008. A credible list, considering AH's location in a relatively urban setting and flanked by two major roads. After the Khoo Teck Puat Hospital was completed and Liak and his team moved to their new premises in Yishun, the old Alexandra Hospital continued to be used as a holding hospital for other new hospitals which were being constructed. In a way, the Butterfly Trail was saved from the excavators of developers.

Over the years, however, the Butterfly Trail fell into neglect, where there was little interest by the new teams who took over the hospital. Understandably, the focus of the new team was on the successful operation of the hospital itself, and the lush greenery around the hospital grounds were tended to pragmatically, purely from the maintenance point of view. Nectaring plants like the Prickly Lantana (Lantana camara), Pagoda Flower, Indian Heliotrope and so on, were replaced or just left to die out, as these were probably considered high maintenance plants.

Alexandra Hospital Butterfly Trail in 2016

Host plants like the Weeping Willow (Salix babylonica) and Soursop (Annona muricata) disappeared, and the associated butterflies moved on to other locations. The varied habitats like the open sunny areas and flowering bushes became heavily shaded as the structure of the greenery evolved as the larger trees grew. Favoured locations where the butterflies used to be sighted, feeding on brightly coloured flowers gave way to heavily shaded low-light vegetation.

A Common Imperial - a species that was regularly sighted at AH Butterfly Trail in the past.  No longer found at the trail today

In its heyday, the AH Butterfly Trail was a must-go-to location for macro and butterfly photographers. Indeed, many of the members of ButterflyCircle started our butterfly photography journey at the very accessible AH Butterfly Trail, and where we learned the names of the butterflies that we photographed. New friendships were forged, and new photographic skills shared and acquired at this trail. Amongst the photography community, it was not unusual to announce over the forums that a photography outing was being planned at a hospital!

Today, the AH Butterfly Trail is a shadow of its former glory, as far as butterfly diversity is concerned. The groups of photographers, regularly seen at the trail on weekends and even weekdays, vanished. Visitors to the trail dwindled and there were even comments online that there was nothing to shoot at the AH Butterfly Trail.

Vegetation at AH Butterfly Trail in 2016 - still lush and green, but where are the butterflies?

I visited the AH Butterfly Trail this morning, to try to understand the reasons behind the downfall of the trail, and to see if there are lessons to be learnt from it. As I drove into the compound of AH, pleasant memories of bygone days flooded my mind, as the familiar surroundings greeted me. After parking my car, and walking towards the trail, I noticed that the lush greenery remained intact. Despite a number of buildings being renovated, the garden areas were generally left untouched. The hospital itself is now under the charge of a new management team and a holding hospital for the new Sengkang General Hospital, currently under construction.

A much heavily-shaded AH Butterfly Trail in 2016

I reached the Butterfly Trail itself, and noted that some of the vistas and the plants were roughly in the places where I remembered them. The main sign, introducing visitors to the butterfly trail had been replaced with a new one, but the area appeared to be under heavier shade than before. Walking along the trail, I saw a total of 3 Common Grass Yellows fluttering amongst the shrubbery. A pair of dogfighting Common Palmflies, Painted Jezebel, Common Mormon, Chocolate Pansy and a Lesser Grass Blue were all that I observed over a period of about an hour and a half that I was there.

The old Aristolochia trellises are still covered with the host plants of the Common Birdwing and Common Rose.  There were even two species of Aristolochia, A. acuminata and A. ringens growing at the trellises.  The plants were pristine and there was no sign of any caterpillar activity whatsoever - the leaves were pristine and unmolested.

Although the skies were cloudy, occasional periods of sunshine bathed the trail. I was hoping to spot more species, but it was not to be. A total of about 10 individual butterflies; 6 species! What happened to the rich butterfly diversity that we used to enjoy? What has changed?

AH Butterfly Trail's nearby catchment which are connected via park connectors and tree canopy

In spite of AH Butterfly Trail's urban location in relatively built-up surroundings, it had several positive things going for it. These were :
  1. The site's proximity to large biodiversity-rich catchment areas in the Southern Ridges like Kent Ridge Park, Telok Blangah Hills Park and Mount Faber Park. The lush tree-lined roads around the site provided good tree-top level connectivity to the further catchments including the Buona Vista area and even slightly further afield northwards to the Singapore Botanic Gardens and southwards to Labrador Park.
  2. Adjacent to AH, is the old Malayan Railway track. Part of the Rail Corridor today, this very critical link cannot be underestimated, as it provides good biodiversity connectivity to areas along this green link much further up north, whilst the undisturbed vegetation along the Rail Corridor itself is a good catchment area for butterflies.
  3. The mature trees and vegetation within the site itself, covering a total of about 11 Hectares, provided a self-sustaining critical mass for biodiversity sustainability.
  4. The tender loving care and passion of Rosalind Tan and her community of helpers. It was well known that Rosalind bred a lot of caterpillars in her own home, and then brought the pupae and eclosed butterflies to the trail to release. She also made sure that there are sufficient plants to sustain different species of butterflies.

Over a decade ago, capitalising on these advantageous attributes of the site, Liak and his team planted the right butterfly-attracting plants and created a mini food haven that brought the butterflies to the AH Butterfly Trail from the well-connected catchments nearby. So why did the butterflies abandon the site in recent years? These are some of my observations :
  1. In the early years, the tree canopy was more sparse and there were areas of high light levels that were conducive to the flowering plants blooming profusely at the Butterfly Trail. Today, the area is highly shaded and amongst the butterfly-attracting flowering plants that remain, only the Snakeweed is left. Even so, without strong sunshine, the amount of nectar that the flowers of the plants that remain may be unattractive to butterflies.
  2. The lower light habitats tend to favour certain species of urban butterflies rather than the sun-loving species, therefore reducing the diversity of species that frequent the trail.
  3. The spraying of pesticides in the vicinity of the Butterfly Trail. This is probably the last "straw that broke the camel's back" as far as the Butterfly Trail is concerned. Already suffering from habitat changes, lack of nectaring and host plants, the spraying of all sorts of pesticides is likely to have pushed the butterfly trail over the edge.
  4. The lack of commitment, enthusiasm and interest amongst those in charge of the butterfly trail. Even though the maintenance of a butterfly trail is much lower than a manicured garden, there is still maintenance needed to replace defoliated plants and nectaring plants occasionally.

A worker spraying air-borne pesticides.  Note the face and eye mask on the worker to protect him from the toxic chemicals.

Coincidentally, when I visited the trail this morning, I encountered two persons spraying the site with pesticides. The first was spraying some form of general pesticide around the Butterfly Trail. Whilst he did not spray within the trail itself, the amount of airborne pesticides may adversely affect the biodiversity in the area. The second man appeared to be carrying some form of Malathion-smelling chemical, as the odour was quite obvious when he walked past and squirted some liquid at the plants along the path.

Another worker spraying Malathion-like pesticide at the Alexandra Hospital grounds

I do not blame these contractors for the spraying of pesticides, as they were just doing their job as instructed. The management of the hospital also has a right to do so, as the priority for the hospital would be to heal sick patients. Garden pests like mosquitoes, ants and other critters would not be priorities in their core mission. If so, then they should not be wondering why the Butterfly Trail is largely devoid of butterflies.

The Plain Nawab was often seen, perched at high level at AH Butterfly Trail.  No longer seen in recent years.

Was Liak the only one who was brave enough to take certain risks when promoting the biodiversity in the gardens around the hospital? Is general spraying of airborne pesticides the solution for eradicating the dreaded Aedes aegypti mosquito that carries the dengue fever virus? The jury is still out on this, and apparently, even some quarters in the NEA do not think so. The most effective method still, is to attack the mosquitoes' breeding grounds i.e. stagnant water.

Caterpillar of the Common Birdwing that was breeding at the Aristolochia acuminata host plants at AH.  Today, the leaves of the host plants are uneaten.

Leadership and commitment from the community are still critical success factors in designing and sustaining a butterfly garden. One does not just "wish" that there will be butterflies and then expect them to appear on demand in an open garden.

A caterpillar of the Blue Glassy Tiger photographed at AH Butterfly Trail in the past.  The host plants are no longer found at the trail today.

The future plans for the redevelopment of the AH healthcare campus is in the works. The Ministry of Health has called a tender for a masterplan and feasibility study on the longer-term use of the site. This will take a year or more to complete. From the initial scope of the study, the greenery where the existing Butterfly Trail sits is to be retained. This is good news. However, what remains to be seen is how the conservation of the biodiversity can co-exist with a more intensive redevelopment proposed on the site.

Will the AH Butterfly Trail regain its popularity with butterfly watchers in future?

Can the AH Butterfly Trail return to its former glory? The answer is, it depends. The critical success factors have not changed much. The interconnectivity between the catchment areas via the park connectors and green canopies are still there. The Rail Corridor, currently being developed, should continue to provide a conduit to the high biodiversity nature areas. What will make the difference, is the human interface, the leadership, enthusiasm and commitment of the people who want to see biodiversity thrive at Alexandra Hospital, or not.

The signature fountain at Alexandra Hospital

Text and Photos by Khew SK

Earlier Blog Article about Alexandra Hospital Butterfly Trail in 2008