21 January 2018

Aberrations in Butterflies

Aberrations in Butterflies
Variations and abnormalities in butterflies

About 10 years ago, an aberration of the Common Rose which has missing hindwing white patches of the normal species appeared in Singapore.  Whilst the status of this variation/form/aberration was unknown, several generations of this black hindwing Rose continued for some time before mysteriously disappearing again. With several similar individuals appearing for some time, it could be a subspecies or a different species, but its disappearance raises some doubt as to whether this "aberration" was caused by genetic or environmental triggers? *1

In the animal kingdom, abnormalities caused by genetic mutations or disorders give rise to aberrations or mutations that are physically different from the norm. The more well-known disorders like albinism (the lack of pigmentation in humans and animals), dwarfism (severely restricted growth, leading to smaller than usual individuals), Down's Syndrome (intellectual disability and characteristic facial appearance), polymelia (born with additional appendages) and too many others to discuss here, have been well-documented in genetic science.

An aberrant Malay Viscount with suffused white markings on the forewings

Aberrations in the butterfly world are not rare as thought. The number of photographs of aberrant butterflies that can be found on the Internet, ranging from minor to extreme aberrations in wing patterns and shapes, is evidence that aberrations are relatively regularly encountered in the field. An aberration is a variation in the wing pattern of a butterfly species which is different in some way to the normal pattern. This can occur as a genetic or environmentally produced/induced variation of the usual form of the species. Some aberrant forms although rare, recur on a fairly regular basis and have been documented as new "forms" of a butterfly species.

An aberration of the Branded Imperial where the dorsal side of the hindwing appears to be orange.  In normally-coloured individuals, the dorsal side of the hindwing is black.

Butterfly aberrations may occur for a variety of reasons - for example, extreme temperature changes especially while the butterfly is developing during the pupal (chrysalis) stage may cause aberrations to occur. Very cold conditions can produce very dark forms of some species while heat shock may cause dramatic changes in wing pattern. Research that subject pupae to cold shock have yielded a wide variety of aberrant patterns and colours in butterflies' wings. In some extreme research, chemical injections into caterpillars and pupae to catalyse change in the butterflies' wing patterns have also been carried out in controlled environments.

An extreme aberration of a Common Bluebottle where almost all the blue pigment is missing from the wings

This article discusses and showcases examples of aberrant butterflies that have been observed in the field, that appear different from normal individuals of the species. Amongst the Papilionidae, there have been cases of minor variations observed. However, one such case stands out as a striking example of an extreme aberration. In the case of the Bluebottle (Graphium sarpedon luctatius) encountered, the macular band across both wings has merged with the wing borders and the absence of the usual blue colour gives it a totally different appearance from the norm.

An aberrant Common Grass Yellow (left) with no cell spots

Minor aberrations in the spots of the Eurema spp. is quite regularly encountered in Singapore. The absence of the diagnostic cell spots in these Grass Yellows often cause confusion as to what species has been observed. In the example shown above, this aberrant Common Grass Yellow (Eurema hecabe contubernalis) shows a total absence of its cell spots and the lack of other spots and features on the wings make it appear like a different species from the normal butterfly.

The Ypthima species are well-known for having aberrant individuals with additional ocelli on the hindwings

Amongst the Satyrinae, aberrations in the form of additional ocelli has been regularly documented in the Ypthima spp. Examples of the Common Three Ring and Common Five Ring are encountered so regularly with additional ocelli that this phenomenon is taken as "normal" that some individuals sport these extra eyespots.

An aberration of the Malayan Bush Brown with a thick, dark marginal border on both wings

This strange looking aberrant Malayan Bush Brown (Mycalesis fusca fusca) sports a marginal black band on both its wings. A normal individual does not have this dark band, but instead has marginal and submarginal zigzag lines which are completely absent in the aberrant individual.

An aberrant Peacock Pansy with very much reduced or absent hindwing ocelli

This aberrant Peacock Pansy (Junonia almana javana) with a reduced or absent large ocellus on the hindwing makes it appear very different from a normal individual of the same species. The ocelli on the forewing also lack the blue and white highlights of a normal Peacock Pansy.

An aberrant Malay Viscount with abnormal forewing markings that make it look very different from a normal individual of the species

This rare aberrant Malay Viscount (Tanaecia pelea pelea) with the highly diffused forewing markings and reduced cell spots makes it appear like a different species at a glance, when compared with a normal individual of the same species. In this case, the aberrations are limited to the forewings only, as the hindwings appear quite normal with the usual markings of the species.

Various aberrations (left, middle) of the Common Hedge Blue

Aberrations amongst the Lycaenidae appear to be quite regular amongst the Polyommatinae species. The variations in these aberrant individuals can range from a heavily darkened wings with heavier markings to additional spots and diffused striations that make the aberrant individual appear like a totally different species. In the example above, the Common Hedge Blue (Acytolepis puspa lambi) on the extreme left appears very different from the normal example on the right. The middle specimen has conjoined spots on the hindwing.

Aberrant markings of the Malayan (left, middle) which give the individuals a much darker and busier appearance than the normal appearance of the species

The Malayan (Megisba malaya sikkima) depicted above also shows a range of variations from left to right, showing examples of melanism in their wings that suggests a different species, if not carefully scrutinised.

An extreme aberration of the Pointed Line Blue (left) gives it an appearance of a different species

This example of a Pointed Ciliate Blue (Anthene lycaenina miya), an aberration with distinct diffuse white markings on both wings makes it appear very different from a normal individual of the same species.

The large black apical hindwing spot and thicker markings on this aberrant Cycad Blue makes it appear very different from a normal individual of the species

The aberrant Cycad Blue (Chilades pandava pandava) with an extra large black apical spot on the hindwing and the suffused markings on both wings depart quite significantly from the normal butterfly's wing markings.

The large hindwing patch on this aberrant female Quedara monteithii monteithii suggests a different species from what it should look like

And finally, amongst the Hesperiidae (Skippers), aberrations are also known to occur. This bred female of Quedara monteithii monteithii appears to have an extra white patch on its hindwings, whereas a normal female features an all-brown hindwing. The aberrant female appears like a different species.

The complete absence of the arrow-shaped black spots on this aberrant Plain Palm Dart, and the paler orange colour makes it look like a totally different species from the normal individual of this skipper

In the above example of a Plain Palm Dart (Cephrenes acalle niasicus) this aberrant individual lacks any of the normal black arrow-shaped markings of a normal individual of this species. Its paler than usual orange colour for this male plus the strange patch that lacks any wing scales whatsoever gives this aberrant individual a very strange appearance.

Text by Khew SK  : Photos by David Chan, Chng CK, Jerome Chua, Khew SK, Bobby Mun, Simon Sng, Michael Soh, Horace Tan, Tea Yi Kai and Benjamin Yam

*1 : Notes on Pachliopta antiphus (Black Common Rose) - The taxonomic position of antiphus is uncertain. It is regarded as conspecific with Atrophaneura aristolochiae by Tsukada and Nishiyama (1982) and Fujioka et al. and but recognized as a separate species by Page & Treadaway (1995). Papilio aristolochiae subspecies poseidippus Fruhstorfer, 1911 and Papilio aristolochiae subspecies kameiros Fruhstorfer, 1911 are both treated as junior synonyms of Pachliopta antiphus antiphus (Fabricius, 1793) by Page & Treadaway (1995)

14 January 2018

Butterfly of the Month - January 2018

Butterfly of the Month - January 2018
The Tawny Coster (Acraea terpsicore)

Mating pair of Tawny Costers - top : male, bottom : female

Here we are, right in the middle of the first month of 2018, and we continue with our feature-butterfly monthly series into its 11th year. The weather is uncharacteristically odd in Singapore for this time of the year and we are enjoying (?) sub-23 deg C temperatures on most days, with the lowest temperature of 21.4 degC recorded in western Singapore in recent years. The persistent wet weather over the past week added to the cold snap as airconditioners were turned off, and tumble dryers doing their fair share to keep the laundry nice and dry.

A taste of climate change to come? The exceptional rain on 8 Jan dumped so much water over the eastern part of Singapore over a couple of hours that the drainage system was unable to cope with the sudden downpour. The ensuing floods in some of the low-lying areas created the first major traffic snarl for the year, coupled with half-submerged cars and damaged properties.

The residents in the eastern US will probably think that a puddle of water in Singapore is nothing compared to the 'bomb cyclone' that dropped a whole load of snow on them. Sub-zero temperatures and foot-high snow closed airports in New York and kept the kids from schools. Even in the warmer south of the US, in Florida, the sudden cold weather caused near-frozen iguanas to drop from trees! So far, we haven't had any records of our local changeable lizards dropping off our trees yet.

The cold and wet weather has kept our local butterfly-watchers indoors as there is very low butterfly activity out in the field anyway. We look forward to warmer weather and bluer skies in the coming months where we can go out and enjoy the beauty of nature's flying jewels again soon. Until then, we can only ponder on the effects of climate change, and what the impacts are, to our environment and biodiversity.

And so we turn to our January Butterfly of the Month, the Tawny Coster (Acreae terpsicore). This species did not appear in Singapore until some time back in 2006. After it reached the shores of Singapore, we postulated its likely voyage all the way from the Indian subcontinent, through Thailand and Peninsula Malaysia. Subsequently, it was spotted in Indonesia, and it is believed to have colonised part of Australia as well. A very tenacious butterfly indeed!

Tawny Coster perched with wings folded upright when resting

Before 2006, it was first spotted by collectors in the northern states of West Malaysia in 1992 as it progressively made its way down the peninsula over the span of at least a decade. The species' journey is most likely aided by the easy availability of its caterpillar host plants, Passiflora foetida, Passiflora edulis and Passiflora suberosa - all fast-growing Passion Fruit vines that are spread by birds that eat their fruits. Its caterpillars were also found on Tuneria ulmifolia another plant of the Passion Fruit family, and it is highly likely that its caterpillars can also feed on other species of Passifloraceae.

Top : Upperside of male Tawny Coster ; Bottom : Upperside of female Tawny Coster

The male Tawny Coster is a deep orange on its upperside whilst the female is a paler orange-yellow. There is a transverse black spot in the cell of the forewing. The underside is generally of a lighter shade of orange with a larger number of black spots on both wings compared to the upperside. There is a marginal row of black-bordered white spots giving the termen of the hindwing a scalloped appearance.

Mating pair of Tawny Coster - Left : female Right: male

The butterfly has a relatively slow flight, usually fluttering restlessly as it moves around to feed on various nectaring sources. Occasionally, it will stop to rest on twigs or upper surfaces of leaves with its wings folded upright. Most of the time, when it stops to feed on flowers, it tends to keep its wings open for balance.

The Tawny Coster is now a permanent extant species in Singapore and is quite common in urban parks and gardens and in undeveloped wastelands where its preferred caterpillar host plant, Passiflora foetida can be found. One of the reasons why this species is so successful may be the way the female lays its eggs - often up to 50 at one sitting and the purported distastefulness of both its caterpillars and adult butterflies.

A newly-eclosed male Tawny Coster holding on to its pupal case

The butterfly is believed to display aposematic colouration in being brightly-coloured and conspicuous. It is likely to be distasteful to birds, as are several other butterfly species that feed on Passifloraceae, e.g. the Lacewings (Cethosia spp). However, it is not immune to attacks from reptiles and mantises - as shown in the photo below where a mantis has ripped off the head of a Tawny Coster that it captured and is eating.

Text by Khew SK : Photos by Bob Cheong, David Chan, Chng CK, Khew SK, Loke PF, Anthony Wong, Mark Wong and Benjamin Yam

07 January 2018

The Singapore Jays

The Singapore Jays
Featuring the Jay Butterflies of Singapore

Reading the title of our first blog article of 2018, one may be forgiven if one thinks the "Singapore Jays" is a musical rock band or something like that. But the pun-ful title is purely coincidental, as in this instance, we are referring to a group of butterflies that are collectively referred to as "Jays". These species belong to the genus Graphium in the family of Birdwings and Swallowtails (Papilionidae).

Two different species of Jays puddling - Left : Lesser Jay  Right : Common Jay

The Jays are very fast-flying and skittish butterflies with unique triangular-shaped wing forms that are predominantly blue or green in colour. Over the years, three extant species have been found in Singapore - the Tailed Jay, Lesser Jay and Common Jay. Subsequently, in 2014, another two Jays found their way into Singapore and have been added to the Checklist. Although these two latter species - the Great Jay and Striped Jay are considered seasonal migrants, they are not uncommon up north in Malaysia.

A pair of Lesser Jays puddling

The males of these Jay species have a common behaviour in that they are often drawn to puddle on urine-tainted sandy streambanks and damp patches of sand or soil that is rich in animal excretions or decomposing organic matter. Being fast-flying and skittish, it is only when they are puddling when a photographer gets the best odds of photographing them with much less frustration. Occasionally though, they stop to perch on the nearby shrubbery after gorging themselves on their liquid diet.

A trio of different Jays puddling together.  Left : Lesser Jay  Middle : Striped Jay  Right : Common Jay

This blogpost introduces the five recorded species of Jays in Singapore and shares some of their behaviour and unique characteristics, host plants and how to distinguish between those species that are very similar in appearance.

The Tailed Jay (Graphium agamemnon agamemnon)

The first of our five Jays, the Tailed Jay is the easiest to identify and is distinctively different from the other Jays in that it has green spots on its wings. It cannot be confused with any of the other Jay species found in Singapore. However, a similar looking species, the Spotted Jay (Graphium arycles arycles), flies in Malaysia and has yet to be found in Singapore. The Spotted Jay lacks the tails at vein 2 of the hindwing of the Tailed Jay, but is similarly coloured.

The Tailed Jay is considered an urban butterfly here in Singapore, where it is often seen in the vicinity of its host plants - Soursop, Champaca and Ashoka Tree, all of which are cultivated and planted along roadside verges in urban Singapore. As its caterpillars feed on a wide variety of host plants, of which two more are found mainly in the forested nature reserves, the Tailed Jay has a widespread distribution from urban parks and gardens to the forested nature reserves.

A Tailed Jay perches on a fern to rest after a puddling feeding frenzy

It is a fast flying butterfly and often seen feeding at flowering plants more than puddling at sandy streambanks. Females are typically larger, and have longer tails than the males. The upperside of the Tailed Jay is dotted with emerald green spots on a black background. The underside features a purple-brown ground colour with green and red spots.

The Lesser Jay (Graphium evemon eventus)

The Lesser Jay, sometimes referred to as the "Blue Jay", is a forest-dependent species and is most often encountered within the forested nature reserves of Singapore. Where it occurs, it is common and at times, several individuals can be encountered puddling together. It has a rapid and erratic flight and is skittish.

An open-winged Lesser Jay showing its blue uppersides

The butterfly's wings are black above, with a blue macular band that runs across the fore and hindwings. There is a series of blue submarginal spots. The underside is a pale silvery blue with deep red spots at the sub-tornal area of the hindwings. The Lesser Jay can be identified by the black costal bar on the underside of the hindwing, where it is united with the basal band.

The early stages of the Lesser Jay has been documented successfully and the caterpillar feeds on Artabotrys wrayi (Annonaceae), which is essentially a forest plant. As such, the butterfly is more often observed in the forested areas of Singapore and rarely seen in urban parks and gardens.

The Common Jay (Graphium doson evemonides)

The Common Jay was first discovered on Pulau Ubin in 2004 and has stayed as a resident of the island ever since

The next extant Jay species that is regularly observed in Singapore is the Common Jay. This species was first observed on the island of Pulau Ubin in 2004 and has largely remained on that island to this day. Although there have been sightings of the Common Jay on Singapore island, it is more often seen on Pulau Ubin, where its caterpillar host plant grows.

The Common Jay is almost indistinguishable from its lookalike cousins when in flight. The typical black wings with a blue macular band and submarginal spots on the upperside makes it almost identical to the other species. However, on the underside of the forewing, the red-centred costal bar is separated from the black basal bar distinguishes this species from the others.

The Common Jay caterpillars have been successfully bred on 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). The Dwarf Ylang Ylang appears to be its preferred host plant that is found on Pulau Ubin.

The Striped Jay (Graphium bathycles bathycloides)

The Striped Jay has the most distinct yellow wingbases compared to the other Jays

The next lookalike Jay species is the Striped Jay. This species was only observed some time in 2014 with a good photo record of it. There were some claims that it was also shot here in Singapore previously, but the records have not been validated. The observation in 2014 was within the nature reserves area where the butterfly was puddling at a sandy streambank.

Again, in this species, the black upperside with a blue macular band and submarginal spots make this species almost identical to its cousins in the genus. The basal area on the underside of the wings is prominently yellow. The diagnostic feature for this species is the costal stripe which is thin and curves away from the basal bar.

The Striped Jay is common in Malaysian forests where several individuals are observed puddling together. There is another closely related Jay that is very similar to this species called the Veined Jay (Graphium chironides malayanum). However, this species has not been seen in Singapore yet.

The Great Jay (Graphium eurypylus mecisteus)

The last species of the Jays observed here in Singapore is the Great Jay. Coincidentally, also spotted in 2014 around the time when the Striped Jay was seen in Singapore, the Great Jay is superficially similar in appearance to the previous three species discussed here. It sports the same black upperside with a blue macular band across both wings, with blue submarginal spots.

Like its other cousins, the Great Jay is often photographed whilst puddling on sandy streambanks in forested areas. The skittish, fast-flying species often puddles together with its other cousins and many other species that like to puddle in numbers. The distinguishing marking on the underside of the hindwing is the red-centred costal bar with is conjoined with the basal band.

A Great Jay puddling to sip essential salts at a damp streambank

The Great Jay and Striped Jay are not considered "resident" species but have been recorded on the Singapore checklist as seasonal migrants. Until a viable colony can be established, they are likely to be seen only occasionally when the conditions are conducive for them to fly over from the neighbouring Johor forests.

So in summary, a visual guide showing the diagnostic features on the underside of the hindwings of the Lesser, Common, Striped and Great Jays is included here for reference. So when you are out in the field, observing some of these lookalikes, do try to spot these features to help you identify which of the Jays that you have encountered.

Text by Khew SK : Photos by David Chan, Bob Cheong, Goh LC, Khew SK, Henry Koh, Jonathan Soong, Horace Tan, Tea YK, Anthony Wong and Mark Wong