09 April 2016

Life History of the Conjoined Swift

Life History of the Conjoined Swift (Pelopidas conjunctus conjunctus)


Butterfly Biodata:
Genus: Pelopidas Walker, 1870
Species: conjunctus Herrich-Schäffer, 1869
Sub-Species: conjunctus Herrich-Schäffer, 1869
Wingspan of Adult Butterfly: 42-45mm
Caterpillar Local Host Plant: Panicum maximum (Poaceae, common names: Guniea Grass).




Physical Description of Adult Butterfly:
On the upperside, the wings are dark brown. There are pale yellowish-white hyaline spots in spaces 2-4, 6-8 and two cell spots in the forewing. Both sexes also have an additional spot in space 1b of the forewing. On the underside, the wings are paler ochreous brown. The forewing has the same spots as per the upperside, and the hindwing has a cell spot and a series of post-discal spots in spaces 2 to 5.



Field Observations of Butterfly Behaviour:
The Conjoined Swift is moderately rare in Singapore. Unrecorded and likely missed by early butterfly researchers, it was discovered recently and added to the Singapore checklist. The adults have been sighted at grassy wastelands and fringes of nature reserves. They fly with a swift, strong and darting flight.

02 April 2016

Butterfly of the Month - April 2016

Butterfly of the Month - April 2016
The Two Spotted Line Blue (Nacaduba biocellata)



All too soon, it's the fourth month of 2016 already! The weather in the northern hemisphere is rapidly warming up, as spring vegetation begins to emerge from the cold winter months. Over in Southeast Asia, temperatures appear to be warming up a tad faster than we would have preferred, with the mercury zooming past 38, 39 and 40ºC in Bangkok, Chiangmai, Penang, Kuala Lumpur and Singapore. In Japan, the Cherry Blossoms bloom heralding the start of the sakura or hanami time of the year.



Even in Singapore, visitors to the Flower Dome at the Gardens by the Bay queued up to partake in the visual treat of blooming Prunus sp. Cherry trees imported from various parts of the world. These trees were horticulturally "tricked" into flowering within the climate-controlled glass dome, creating Singapore's own sakura for visitors to enjoy.



Up north in Beijing, where I was attending a business conference, the weather was a crispy 13-16ºC in the daytime, dropping to a chilly 2-4ºC at night. Even so, the winds blew away the pollution and the air was clean and clear. The hotel where we had the conference at was about 100km away from the city centre, and the surrounding views were spectacular! Magnolia buds have started appearing on their leafless trees, all ready to bloom as springtime temperatures trigger renewed life, as it does year after year.



On the global front, the spectre of religious extremism and radicalisation continues with terrorist acts claiming innocent lives of women and children. Two recent suicide bombings in Brussels, Belgium and Lahore, Pakistan claimed the lives of over 100 people. Other than these high profile cases which are featured internationally, it is terrifying when one is informed about the number of less well-known terrorist attacks all over the world, all in the first 3 months of 2016 alone!



The construction industry in India was thrust into the limelight when a massive flyover collapsed in Kolkata (formerly Calcutta) and killed more than two dozen people. The purported lack of inspections and quality of material used by the "blackmarked" contractor was cited as possible causes. This led me to think about how we architects and engineers often lament about the highly regulated construction industry in Singapore where the Building and Construction Authority (BCA) and many other agencies tend to "over-regulate". Perhaps we have to be thankful for that after all!



Workplace safety was in the limelight in Singapore, where two engineering technicians were killed when they were knocked down by a moving train whilst en route to check a track fault. This brings into question, the level of workplace safety procedures in such hazardous industries. In the engineering and construction industry, where foreign workers make up a higher proportion of the workforce, workplace health and safety is always a concern where 'one life lost is one life too many'.



Speaking of foreigners and immigrants, we feature a non-local butterfly species that was discovered some time back in 2004 - the Two Spotted Line Blue (Nacaduba biocellata). This immigrant species is a diminutive 16-22mm in wingspan and is unlikely to have made it all the way from Australia, its native home, to Singapore. The fact that its caterpillar host plants are also non-native invasives - the Black Wattle (Acacia auriculiformis) and the Silver Wattle (Acacia mangium) makes it curious as to how these "foreigners" got to Singapore.



Both the host plants are considered invasive "weeds" and often removed by parks managers due to their brittle trunks and branches and are susceptible to breaking and collapsing. Surely they could not have been imported by horticultural companies where the caterpillars and pupae of the butterfly may have stowed away on? If so, then how did the butterflies appear in Singapore?



The male Two Spotted Line Blue is lilac with dark blue basal area while the female is dull brown with varying degrees of blue in the basal area. Both sexes have two brown-black subtornal spots on the hindwing. Underside, both sexes are similarly marked. The underside is pale greyish-orange in base colour with a short band at cell-end, and a longer post-discal band, both of which are narrowly edged with brown and white. The hindwing features two black subtornal spots with a few iridescent green scales and ringed with pale yellow-brown.



The species is skittish and often flies erratically for long periods of time without resting. An interesting phenomenon about the Two Spotted Line Blue is that its appearance in Singapore is highly seasonal. It suddenly appears as a outbreak, where literally hundreds of individuals may be observed over a few days, fluttering around the vicinity of its host plant. And then it disappears for the rest of the year, with not a single individual seen until the next outbreak!



It is often mistaken for the more commonly found Tailless Line Blue (Prosotas dubiosa lumpura) which displays a similar behaviour and outbreak over the year. Until an individual stops to rest and shows its distinctive two tornal spots, the two different species are usually difficult to distinguish when it flight.



Sightings of the Two Spotted Line Blue have been quite regular over the years so as to conclude that this species has somehow been naturalised and considered a "permanent resident" in Singapore. Its caterpillar host plants, as mentioned earlier, grows easily and appears in undeveloped areas all over Singapore. The full life history has been documented and can be found on this blog here.



It is hoped that this species will continue to survive in Singapore, despite the mystery of how it immigrated to Singapore. Being seasonally common, it is also a mystery of nature how its caterpillars or pupa is able to 'hibernate' and appear again the next season. This species has not been recorded in Malaysia yet, and should be looked out for in Singapore's neighbouring state of Johor.

Text by Khew SK : Photos by James Chia, Sunny Chir, Khew SK, Koh CH, Horace Tan and Anthony Wong

Cross References on this Blog :

26 March 2016

Larval Host Plant for Butterflies: Yellow Saraca

Butterflies' Larval Host Plants #8
The Yellow Saraca (Saraca thaipingensis)


This 8th instalment of our Butterflies' Larval Host Plants series features Saraca thaipingensis (Yellow Saraca), a species of the family Fabaceae (Bean Family) which has members taking on a variety of growth forms (tree, shrub, herb, vine, liana). The Yellow Saraca is a perennial member of this family which assumes the tree form. The species name "thaipingensis" has the meaning "of or from Taiping, Malaysia".



Yellow Saraca is native to the Southeast Asia region, but it is also widely cultivated in a number of tropical and sub-tropical countries for its attractive yellow inflorescence and drooping pink/purple young leaves. In Singapore, the Yellow Saraca can be found in many parks and gardens as ornamental trees. Besides its obvious ornamental purpose, Yellow Saraca has potential medicinal uses as extracts of its flowers, leaves and twigs have been found to have antimicrobial and antioxidant properties in recent studies.


Plant Biodata :
Family : Fabaceae
Genus : Saraca
Species : thaipingensis
Synonyms : S. cauliflora, S. declinata, Jonesia declinata.
Country/Region of Origin :  Southeast Asia
English Common Name : Yellow Saraca, Yellow Asoka,
Other Local Names :  Gapis Golak, Talan, Bunga Asoka, Gapis, Gapis Batan, Gapis Batang, 黄花无忧树
Larval Host for Butterfly Species: Hypolycaena erylus teatus (Common Tit), Jamides caeruleus caeruleus (Sky Blue), Jamides alecto ageladas (Metallic Caerulean), Jamides elpis pseudelpis (Glistening Caerulean), Semanga superba deliciosa, Drupadia ravindra moorei (Common Posy), Rapala pheretima sequeira (Copper Flash), Anthene emolus goberus (Ciliate Blue).

A Yellow Saraca tree next to the Symphony Lake in the Singapore Botanic Gardens.

Yellow Saraca is a medium-sized, evergreen tree which can grow up to about 8m in height. The fully grown tree has a wide spreading crown.

A flowering Yellow Saraca tree in the Mount Faber Park.

Another Yellow Saraca tree in the Singapore Botanic Gardens.

Leaves of the Yellow Saraca are simple pinnate (with no terminal leaflet) with 4 to 8 pairs of opposite leaflets, each of which is lanceolate in shape and can grow up to 8-25cm long. Young leaves occurs in drooping form and are initially dark reddish brown. As it grows larger, the tender leaflets turns pink or purple colour, before finally turning green and stiffen.

Young leaves of the Yellow Saraca in its early stage of development.

Drooping young leaves of the Yellow Saraca in cream/pink coloration.

A wide-field view of both young and mature leaves of the Yellow Saraca.

A Yellow Saraca tree in Singapore Botanic Gardens with attractive pink/purple young leaves.

Mature leaves of the Yellow Saraca.

Flowers of the Yellow Saraca occur in dense clusters each of which is up to 40cm broad and arises from trunk, stems or branches. Each flower is small, about 2cm in diameter, initially pale yellow, turning deep yellow with a crimson eye-spot. Most flowers are functionally male with the rest bisexual. Flowers of the Yellow Saraca are mildly fragrant. It is interesting to note that each flower bears no petals but 4 sepals.

Clusters of flower buds of the Yellow Saraca arising from a branch.

Closer view of a cluster of flower buds of the Yellow Saraca.

Closer view of a cluster of flowers of the Yellow Saraca.

Left: A functionally male flower; Right: A bisexual flower of the Yellow Saraca.

Each fruit is a thin and flat pod. When fully developed, it is purple and large, 20-45cm long and 4-8cm broad. When ripened, the fruit turns dark brown and splits into two halves, exposing the flat, black seeds.

Young pods of the Yellow Saraca in very early stage of development.

Fully developed pods of the Yellow Saraca.

Ripened pods of the Yellow Saraca.

When a Yellow Saraca tree is in bloom, it could attract many nectar-seeking visitors such as various species of butterflies, other insects and birds.


Butterflies visiting flowers of the Yellow Saraca.


Various insects found on flowers of the Yellow Saraca.

A nectar-seeking bird found among flower clusters of the Yellow Saraca.





In Singapore, the Yellow Saraca also serves as the larval host plant for eight butterfly species: Common Tit, Sky Blue, Metallic Caerulean, Glistening Caerulean, Semanga superba deliciosa, Common Posy, Copper Flash and Ciliate Blue. All are lycaenid.


Clockwise from upper left: Ciliate Blue, Common Tit, Semanga superba deliciosa, Common Posy.


Clockwise from upper left: Sky Blue, Glistening Caerulean, Copper Flash, Metallic Caerulean.

Eggs of these butterfly species are laid on flower parts or on the surface of young leaves or stem. In the case of the Ciliate Blue, the eggs are laid in a tight cluster while those of the other seven are laid singly.

A female Glistening Caerulean laying an egg in the flower cluster of the Yellow Saraca.

An egg of the Sky Blue laid on a flower sepal of the Yellow Saraca.

Caterpillars of the three Jamides species and Copper Flash feed on the flower parts of the Yellow Saraca, whilst those of the Common Tit, Common Posy, Semanga superba deliciosa and Ciliate Blue feed on young leaves of the Yellow Saraca. They possess the usual nectary organs which attract attending ants.

A caterpillar of the Glistening Caerulean on the flower part of the Yellow Saraca.

A caterpillar of the Sky Blue on the flower part of the Yellow Saraca.

A caterpillar of the Metallic Caerulean on the flower part of the Yellow Saraca.

A caterpillar of the Ciliate Blue being attended by a group of weaver ants.

A caterpillar of the Common Posy resting on a leaf of the Yellow Saraca.

A caterpillar of Semanga superba deliciosa on a leaf of the Yellow Saraca.

A caterpillar of the Copper Flash nibbling away on a flower of the Yellow Saraca.

Caterpillars of these lycaenid species pupate either on a leaf surface or in a leaf litter. In the case of the Common Posy, the pupation site is typically a spot on a stem or branch.

Two views of a pupa of the Ciliate Blue on a young leaf of the Yellow Saraca.

Two views of a pupa of the Metallic Caerulean on a leaf surface.

Two views of a pupa of the Common Posy on a stem.

With so much insect and bird activities observable in a blooming Yellow Saraca tree, it is always worthwhile to check out such a tree that you happen to chance upon in one of our many parks and gardens.

References:
Text and Photos by Horace Tan.