Life History of the White Palm Bob

Life History of the White Palm Bob (Suastus everyx everyx)

Butterfly Biodata:
Genus: Suasus Moore, 1881
Species: everyx Mabille, 1883
Sub-species: everyx Mabille, 1883
Wingspan of Adult Butterfly: 24-28mm
Caterpillar Local Host Plant: Daemonorops augustifolia (Arecaceae; common name: Water Rattan Palm).

Physical Description of Adult Butterfly:

The adults are diminutive in size. Above, the wings are brown and typically unmarked. In some female specimens, small white spots might be present in space 2 and the cell in the forewing. In the hindwing, the tornal area and tornal cilia are white. Underneath, the wings are brown and overlaid with buff scaling. In the hindwing, the lower two-thirds are white with several dark spots of varying sizes. The abdomen is brown and white banded.

Field Observations of Butterfly Behaviour:

The White Palm Bob is rare in Singapore. Sightings are rather localized to a forested area in a reservoir park. They are usually found flying in the deep shaded area near ground level. At times, they are also sighted puddling on wet ground and on bird droppings.

Early Stages:

Thus far only one local host plant, the Water Rattan Palm, has been established for White Palm Bob. This plant is rather common in the forested area where the species resides. The caterpillars feed on leaves of the host plant and live in leaf shelters. In all instars, the caterpillar builds tent-like shelter on the underside of a leaflet by cutting and joining leaf fragments. As the caterpillar grows in size later through progressing instars, it will construct ever larger shelters. In the final instar, two adjacent leaflets are typically used as a larger shelter is necessary for housing the much larger larval body.

Local host plant: Daemonorops augustifolia (Water Rattan Palm).

The eggs are laid singly on the upper surface of a leaflet of the host plant. Each shallow dome-shaped egg is wine red with yellowish to whitish longitudinal ridges emanating from the polar region where the micropylar is sited. The eggs are rather small with a diameter of about 1mm.

A far view of an egg laid on the leaflet of the Water Rattan Palm.

Two views of an egg of the White Palm Bob, diameter: 1mm.

It takes about 4 days for the egg to hatch. The egg decolorises to yellowish brown colour when fully mature on the last day of this phase. The young caterpillar eats just enough of the shell to emerge. Its golden yellow body has a length of about 2mm. There is a tuff of moderately long setae on the posterior segment. The head is comparatively large and is yellowish brown in colour.

A sequence of three views of a mature egg on the last day of the oval stage.

Two views of a newly hatched caterpillar taking a bite of its egg shell.

Two views of a newly hatched caterpillar, length: 2.1mm.

After emerging from the egg, the caterpillar makes only a weak attempt at eating the egg shell remnant before moveing on to the leaf edge to construct its first leaf shelter. Its body takes on a slight green undertone after a few feeding sessions near its shelter. The 1st instar takes a total of 3 days to complete with body length reaching about 4mm.

Two views of a 1st instar caterpillar, length: 3.6mm.

Top: the leaf shelter of a 1st instar caterpillar. Bottom: the same leaf shelter opened to show the resident caterpillar.

The body of the 2nd instar caterpillar is yellow with a green undertone and the head capsule is pale yellowish brown. The tuff of moderately long setae at the posterior end is now absent, being replaced by a few short setae. This instar lasts a total of 3-4 days with the body length reaching up to 6mm.

A newly moulted 2nd instar caterpillar, length: 3mm.

Two views of a 2nd instar caterpillar, length: 5.5mm.

In the 3rd instar, the body colour decolorises from yellow to whitish as growth progresses. The head is paler in coloration compared to the earlier instars. This instar lasts a total of 4-5 days with the body length reaching 8-9mm.

Top: late 2nd instar caterpillar, dormant prior to its moult. Bottom: newly moulted 3rd instar caterpillar.

Two views of a 3rd instar caterpillar, length: 7mm.

The 4th instar ushers in an obvious change in the head capsule where the base colour is now pale brown to white and there are numerous brown spots dotting the lateral sides. The body is also adorned with numerous tiny, white spots and a faint, narrow, whitish, lateral band runs along lengthwise. This penultimate instar lasts 4-5 days with the body length reaching 12-14mm.

Top: leaf shelter of a White Palm Bob caterpillar. Middle: the same leaf shelter opened to review a late 3rd instar caterpillar. Bottom: the same caterpillar newly moullted to the 4th instar.

Two views of a 4th instar caterpillar, length: 11mm.

As in the 4th instar, the body of the 5th instar caterpillar is mostly translucent with numerous, tiny, white spots and has a white lateral band running lengthwise. The head capsule is also similar to those in the 4th instar except that the contrast between white base colour and the brown spots are now much more prominent. The periphery of the head capsule is marked in brown.

Top: leaf shelter of a White Palm Bob caterpillar. Middle: the same leaf shelter opened to review a late 4th instar caterpillar. Bottom: the same caterpillar newly moullted to the 5th instar.

Two views of a 5th instar caterpillar, late in this stage, length: 21mm.

The 5th instar takes about 7-8 days to complete with the body length reaching 21-22mm. In the last 1-2 days of this instar, the caterpillar seeks out a new site on a leaflet to construct its leaf shelter. Within the pupation shelter, a large amount of silk threads are spun and a great mass of whitish powdery substances are secreted to coat the inner surface of the shelter. Typically the pupation shelter is cut from the leaflet before the caterpillar proceeds to seal the shelter. This prepupatory phase lasts for 1.5-2 days.

Top: a detached pupation shelter. Bottom: the same shelter opened to reveal a fresh pupa.

Pupation takes place within the leaf shelter. The pupa does not have a cremastral attachment nor a silk girdle. The body is pale green in the thorax and wing pad areas, but yellow in the abdomen. As is common in the case of pupation within a closed shelter for skipper species, purged frass pallets and the exuvia and head capsule of the final instar caterpillar can be found near the posterior end of the pupa. Length of pupae: 13.5-15mm.

Two views of a pupa of the White Palm Bob, length: 13.5mm

After 8 days, the pupa becomes mostly dark brown to black as the adult development stage within its case comes to an end. Eclosion takes place the next day.

Two views of a mature pupa of the White Palm Bob.

A newly eclosed White Palm Bob.

References:

• [C&P4] The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, Malayan Nature Society.
• Butterflies of Thailand, Pisuth Ek-Amnuay, 2nd Edition, 2012
• A Field Guide to the Butterflies of Singapore, Khew S.K., Ink On Paper Communications, 2010.

Text by Horace Tan, Photos by Nelson Ong, Loke PF, Federick Ho, Sunny Chir, Khew SK and Horace Tan.

Poplar Surprise

 

The last few moth trappings have been a little disappointing but with the wind dying off last night I thought it was worth another go. About 10pm I had a look and while I was by the trap an Old Lady moth landed on the trap briefly and then vanished. Unfortunately this huge moth did not reappear and was not there this morning. A Cypress Pug was interesting but the surprise was a late Poplar Hawk Moth that was still in very good condition.

 

 

 

 

Yesterday I had a short trip to High and Over where I looked for Wall Brown ova (more of this to follow). I also saw several fresh Speckled Wood. It is so easy to ignore these common butterflies, but when they are really fresh they can be well worth a bit of effort. I particularly like the eye spots on the hindwing of this particular individual.

 

 

Butterflies Galore! : Aberrant Oakblue

Butterflies Galore!
The Aberrant Oakblue (Arhopala abseus abseus)

The distribution of this distinctive but very small Arhopala is quite intriguing. Whilst many of its other related species are mainly forest denizens, preferring the forested and shady sanctuaries in the nature reserves, the Aberrant Oakblue has also been observed at various urban parks from Fort Canning Park, Singapore Botanic Gardens and Ang Mo Kio West Town Park, just to name a few. It is more regularly observed in forested areas where it lurks in the shaded understorey. It is also a small species but is distinctively marked compared to other Arhopalas. Another key feature is its three pairs of white-tipped tails, of which the pair at vein 3 of the hindwing is the longest.

This pristine individual, shot by ButterflyCircle member Jonathan Soong, was observed at the Singapore Zoological Gardens at Mandai. The Aberrant Oakblue is considered a moderately rare species and is usually observed singly whenever it occurs.

Butterflies Galore! : Lesser Harlequin

Butterflies Galore! 
The Lesser Harlequin (Laxita thuisto thuisto)

This shade-loving denizen is mainly found in the forested nature reserves of Singapore. It is considered rare and there are times when the species is not seen for long periods of time. Like the other species in the family Riodinidae, the Lesser Harlequin is often encountered flitting from leaf to leaf and twisting and turning with half opened wings. The underside is orange-brown with blue edged black spots. Males are all-black above, whilst the females have similar patterns as the underside.

Last weekend, BC members stumbled on a colony of the Lesser Harlequins where a few individuals, both males and females, were observed at a forest trail in the nature reserves. This shot of a male Lesser Harlequin was taken by ButterflyCircle member Sunny Chir.

Drifting Back 2

 

I haven't been able to do too many longer trips this year unfortunately but in May I did manage to do one of my favourite trips. A round trip starting near Heyshott for Birds Nest Orchids followed by the Duke of Burgundy on Heyshott Down and then up to Botany Bay and Tugley Wood for the Wood White. I took Pete Varnham with me as he had never seen the Duke before, and it had been many years since he had seen the Wood White. It was a very successful day with all the targets achieved.

 

The Duke of Burgundy

 

 

 

 

and Wood White

 

 

and the Birds Nest Orchids.

Butterflies Galore! : Sumatran Gem

Butterflies Galore!
The Sumatran Gem (Poritia sumatrae sumatrae)

The Sumatran Gem is a forest-dependent species and is rarely found outside the sanctuary of the deep shady habitats within the nature reserves in Singapore. It is very local in distribution, although several individuals may often be seen flying together in a small area. The underside of the butterfly is predominantly brown, with dark reddish striations. Males are more often seen than females. The male tends to open and close its wings as it flits to a new perch, but then subsequently stops and stays still with its wings folded upright unless disturbed.

The males are iridescent green on the upperside, with a thick black apical border, whilst the females are purple with dark reddish markings and borders. ButterflyCircle member Huang CJ encountered these two males side-by-side and got an opportunistic and unstaged shot, giving an interesting composition to this moderately rare species from the subfamily Poritiinae, of which there are only two representatives in Singapore.

Swallowtail

 

Early evening yesterday I had a phone call from Michael Blencowe advising me that a Swallowtail was near Wilmington. Unfortunately I was unable to get over there then but as it had rained all night I decided that there was still a very good chance that the butterfly was likely still to be in the same area today. Not perhaps ideal weather for butterfly watching but as it appeared to brighten slightly I took advantage and shot over there with instructions as to where it had been. Amazingly it was still there and as a warmer and brighter patch arrived the butterfly opened its wings for a while. An amazing sight to see this rare migrant in Sussex. My thanks to Michael for letting me know about it and to David Bradford who originally found it.

 

 

 

 

 

 

 

It's a Bird! No, it's a Butterfly!!

It's a Bird! No, it's a Butterfly!!
Jays and Albatrosses


A Common Jay perches on a leaf

Recently, during a visit to the California Academy of Sciences tropical rainforest conservatory in San Francisco, a young boy next to me exclaimed to his mother, "Look, mommy, a pretty Blue Jay!". I turned around quickly, expecting to see a fast-flying individual of Graphium evemon that I am familiar with. But no, it was a bird. Pretty no doubt, but certainly a bird and not a butterfly!

A Blue Jay puddling on sandy ground

Not too long ago, I wrote a post on the common English names of some butterflies in the region, and some theories behind how the names were coined. In that article, the names mainly came from military and aristocratic titles. My recent experience in San Francisco reminded me that there are quite a few groups of butterflies that shared common English names with birds. A look at some of the literature available yielded a few groups of butterflies in Singapore that had names of birds.

A puddling Tailed Jay

This article features just two groups of them - one from the Papilionidae family and the other from the Pieridae family that has common names that may confuse these butterflies with birds! There are others, which I will leave for future articles. The first group that will be featured in today's blog post, are the Jays.

The Jays

If we google the name "Blue Jay", and look for websites or images, chances that the search will feature more bird articles and images than butterflies. In the world of ornithology, the collective group Jays refer to several species of medium-sized, usually colourful and noisy, passerine birds of the crow family, Corvidae. In the image below, an image search yielded many photos of this pretty blue bird of which there are several different species in North America and Canada.

A screen capture of images after googling "Blue Jay"

Back in our world of lepidoptera, a Blue Jay refers to the species Graphium evemon eventus a fast-flying swallowtail that is relatively common in our forested areas in Singapore. It is regularly observed puddling at muddy banks of streams. The collective term "Jay" also features two other species in Singapore - the Common Jay (Graphium doson evemonides) and the Tailed Jay (Graphium agamemnon agamemnon)

A puddling Blue Jay

The Common Jay is found more regularly on the offshore island of Pulau Ubin where its host plants, Desmos chinensis (Annonaceae, common name: Dwarf Ylang Ylang), Michelia alba (Magnoliaceae, common name: White Champaca), Polyathia longifolia var. pendula (Annonaceae, common name: False Ashoka Tree), grow quite commonly. Its life history has been recorded in our blog here.


A puddling Common Jay

The third Jay is the green-spotted Tailed Jay. A common urban butterfly, the caterpillars of this species feed on the Soursop plant, amongst several other species of alternative host plants. This species is found in urban parks and gardens as well as in the forested areas of our nature reserves. This is the largest species in the genus Graphium. Over in Malaysia, there are at least three more species of the same genus that bear the English common name "Jay".


Another puddling Tailed Jay

So the next time you are out in the field and someone shouts look at that "Jay", don't just assume that it is a butterfly that will fly past. Although in equatorial Singapore, it would be unlikely that it will be a bird! Perhaps the collector who first coined the name "Jay" for butterflies is most likely a non-local who associated the blueness of the butterfly with a bird from his home country?

The Albatrosses

The second group of bird-butterfly common name is the Albatross. Again, from the ornithological viewpoint, the Albatross belongs to the family Diomedeidae. This family features magnificent birds that are usually associated with coastal habitats. Albatrosses are among the largest of flying birds, and the Great Albatross (genus Diomedea) has the largest wingspans of any extant birds, reaching up to 12 feet (3.7 m).


A screen capture of images after googling "Albatross"

Although it is unlikely that we will encounter one of these large birds in Singapore, yelling out the name "Albatross" to a group of visiting bird watchers from temperate countries may invite curious stares and raised eyebrows! Two species of butterflies, the Striped Albatross and the Chocolate Albatross, occur here in Singapore.


A male Striped Albatross feeding on a Bidens flower

The Striped Albatross (Appias libythea olferna) is a common urban butterfly, that frequents parks and gardens on bright sunny days. The caterpillar of this species feeds on a common "weed" Cleome rutidosperma. The male butterfly is predominantly white, with black veins, whilst females have grey shaded wings. The Striped Albatross has a fast and erratic flight but is certainly less majestic than its gliding avian namesake.


A female Striped Albatross feeding on a Bidens flower

The Chocolate Albatross (Appias lyncida vasava) on the other hand, is seasonal and does not appear to be a resident species in Singapore. Up north in Malaysia, it is very common, and even seasonally abundant. During certain months of the year, the Chocolate Albatross may be observed in Singapore. At times, there may be several individuals seen together in local areas.


A male Chocolate Albatross puddling

The Chocolate Albatross is also a fast flying butterfly and in its native country Malaysia, up to 20 or more individuals have been often observed, puddling together at sandy riverbanks, together with other species of butterflies. The distinctive bright lemon yellow hindwing in the male separates it from any other species of butterflies. Females are rare and often seen feeding at flowers and flying in the forested areas.


A male Chocolate Albatross with half-opened wings basking in the sunshine

So there you have it, two groups of butterflies that share common names with our feathered friends. Although the similarities between butterfly and bird are hard to associate, it is likely that the Jays were coined as names for butterflies of the Graphium genus that are mainly blue, reminiscent of the blue coloured birds of the same name. For the Albatrosses, it is also possible that the butterflies, which are predominantly white when in flight, reminded the original author of the magnificent ocean-going birds of the northern hemisphere.

Text by Khew SK : Photos by Chng CK, Huang CJ, Khew SK, Koh CH, Bobby Mun & Anthony Wong