Hidden in Plain Sight!

Hidden in Plain Sight!
Discovery of the female Malay Staff Sergeant


Abstract of the paper published in Raffles Bulletin of Zoology

The recent publication of our paper in the Raffles Bulletin of Zoology Vol 68(2020) on 29 Apr 2020 entitled the "Discovery of the previously overlooked female of Athyma reta, and its taxonomic implications" was a culmination of over 4 years of research and meticulous studies of references and specimens across the region. The discovery that the female of the Malay Staff Sergeant (Athyma reta moorei) is black-and-orange started as far back as 2015, when our early stages expert, Horace Tan stumbled upon the caterpillars of the Malay Staff Sergeant in Singapore and bred a few batches of the caterpillars.


A mating pair of the Malay Staff Sergeant - one of the pieces in the puzzle that led to the discovery of the black and orange female

The study took a long time to complete because of the thorough examination of some 90 specimens. The paper compares the early stages of the Malay Staff Sergeant with the Colour Sergeant. It analyses the colour patterns of the females using statistical techniques in order to find the best distinguishing characters of these females that can be so difficult to tell apart. In addition it explores the possibility of other female forms existing in the Malay Staff Sergeant, just as they do in the Colour Sergeant, but we came to the conclusion that the female is always black-and-orange. The paper also discusses many taxonomic implications of the new finding.

Specimens of male/female, upperside/underside of Malay Staff Sergeant (top) and Colour Sergeant (bottom)

Based on existing literature and references, the Malay Staff Sergeant has been described as "sexes similar" (e.g. in Fleming), implying that the male and female of the species are similar. In various books, ranging from Butterflies of the Malay Peninsula to Butterflies of Thailand, only males were shown. Even in the classic online reference that many of us often refer to, Inayoshi-san's site, A Check List of Butterflies in Indo-China, only a male specimen of Athyma reta was depicted. Many other regional references imply that the species is sexually monomorphic.


Colour Sergeant female f-neftina

Malay Staff Sergeant female

Over the years, both butterfly experts and enthusiasts accepted that the Malay Staff Sergeant is sexually monomorphic. A number of references even show photos of the so-called black-and-white females. Originally, early authors thought that the Malay Staff Sergeant may be sexually dimorphic, but that possibility was eventually overlooked. Everyone followed Fruhstorfer in thinking the female was like the male. Except in India. In India, strangely, they thought the female was black-and-grey-brown. This was actually because the Colour Sergeant's female-form subrata was confused as the female of the Malay Staff Sergeant. In fact, the article shows that the Malay Staff Sergeant most likely does not occur in India or even north of South Thailand.


Colour Sergeant female f-neftina upperside

In examining specimens in collections that were purportedly black-and-white females, all of them were actually males of the Malay Staff Sergeant. This paper and discovery is hence of major taxonomic significance. It changes the identification keys and descriptions of Athyma reta and its related species.


Colour Sergeant female f-neftina underside

Whilst the paper is prepared with the expected scientific rigour and detailed research commensurate with the standard of a peer-reviewed scientific publication, many layman readers may find the level of information rather daunting to try to understand. Hence, what do the conclusions and outcomes generally mean for the nature enthusiasts, hobbyists, photographers and layman readers on social media and online platforms?


Colour Sergeant female f-neftina

Malay Staff Sergeant female

Comparison of the forewing arrowheads in museum specimens

Basically, to many of us who are out in the field, and who are interested in photographing butterflies and trying to put accurate names to what we have shot, the paper tells us that :
a) the species Malay Staff Sergeant is sexually dimorphic - the male is black-and-white and the female is black-and-orange.
b) the female resembles the female of the more commonly seen species, the Colour Sergeant's orange female form-neftina.
c) many of our images that we have labelled as Colour Sergeant female f-neftina may actually be a female of the Malay Staff Sergeant.



Annotated diagrams of the 2 key diagnostic features between the Malay Staff Sergeant and the Colour Sergeant

So how do we differentiate the two? In the paper, two reliable key diagnostic characteristics that separate the two species are described :
a) the thoracic band on the upperside of the butterfly. It is orange or yellow in the Malay Staff Sergeant, but is white in the Colour Sergeant female f-neftina.
b) In the Malay Staff Sergeant, the upper margin of the basal half of the cell-end arrowhead is convex, whilst in the Colour Sergeant, it is concave.


Colour Sergeant female f-neftina - on the underside, the markings and bands are narrower, with a light pinkish tinge

Malay Staff Sergeant female - on the underside, the markings and bands are much wider, and generally pale orange.

Other less reliable (or visually discernible) differences are :
a) wider orange markings in Malay Staff Sergeant.
b) clearer submarginal spot in space 4 of the forewing upperside between the postdiscal and narrow marginal bands
c) a generally stronger orange colour on the underside
d) more orange scaling flanking the underside markings
e) pale orange underside bands and spots, instead of almost white with pink/orange tint in the Colour Sergeant.



Underside and upperside of different individuals of the female Malay Staff Sergeant

The paper is a good example of cross-border collaboration between Malaysia and Singapore, with Dr Laurence Kirton and Dr Phon Chooi Khim coming in to present the findings in a manner that meets the stringent requirements of a refereed journal like the Raffles Bulletin of Zoology. They used their expertise to analyse the data from various perspectives and putting across the findings and observations with full scientific rigour.


A female Malay Staff Sergeant sunbathes on the top of a leaf

Finally, the elusive female Malay Staff Sergeant has been discovered. It was there all the time, in museum and private collections, and photographic folders on our hard drives. It was indeed "hidden in plain sight" all this time. For those of us with photos that have been filed as Colour Sergeant female f-neftina, it is time to take a re-look at our archives.  You may have a shot of that elusive female Malay Staff Sergeant after all!



Text by Khew SK and LG Kirton : Photos by Brian Goh, Huang CJ, Khew SK, Koh CH, Simon Sng, Jonathan Soong and Horace Tan

Special thanks to Drs LG Kirton and Phon Chooi Khim (FRIM, Malaysia) and A/Prof Horace Tan for making this discovery possible.

Butterfly of the Month - September 2020

Butterfly of the Month - September 2020

The Malay Staff Sergeant (Athyma reta moorei)

A typical male Malay Staff Sergeant with the twice-constricted forewing cell streak

The month of September 2020 is well into its second half, and this year, the first half of the month coincided with the Chinese Hungry Ghost Festival. In Chinese folk legend, the seventh lunar month is the Ghost Month. It is said that every year on the first day of the seventh lunar month, the Gates of Hell will be wide open and the ghosts will come out until the gates are closed on the 30th day of the month, which fell on the 16 Sep this year. So we are now into the 8th month of the Lunar Calendar, and looking forward to delicious moon cakes.

The COVID-19 situation in Singapore appears to be improving, with low double digit infection cases in the recent few days, and few or no cases at all in the community. This is a good sign that the pandemic is well under control, and Singaporeans from all walks of life look forward to further relaxation of the controls that were put in place to manage the spread of the virus. But all these controls have been at the expense of the economy - and a valid trade-off.  Even so, Singapore's estimated Gross Domestic Product (GDP) for the full year is expected to land somewhere between -6% to -7% - its worst economic contraction since its independence in 1965!

As the economy takes a severe beating, the spectre of increased unemployment, job losses and salary cuts loom over the horizon. There is little cheer in the atmosphere, as our island state braces itself for the stormy seas ahead. Even as the government rolls out various measures to ease the pain of businesses and individuals, such schemes are not sustainable in the long term, and various sectors are compelled to craft new strategies to adapt to the new norm and reinvent their businesses to stay afloat.

The race is on, for a vaccine to eliminate the never-ending outbreaks and recurrence of the virus. Optimistically such a vaccine is hoped to wipe out the COVID19's effect across the globe. The current estimate of infections globally has already passed 30.8M with over 958,000 fatalities due to the virus.  The numbers continue to climb every day, with the US, India and Brazil taking the top three spots for total infections. And the world continues to search for a solution to end one of the most deadly pandemics in modern history.

Our Butterfly of the Month for September 2020 is a species that has recently made the news in taxonomic circles. The female of the Malay Staff Sergeant (Athyma reta moorei) had eluded many taxonomists and butterfly experts all this time. The discovery that the species is actually sexually-dimorphic was only made this year, after years of careful research and life history documentation. It is now confirmed that there is unlikely to be a black-and-white female of the Malay Staff Sergeant, and that the female is orange and black all along.

A puddling male Malay Staff Sergeant

The Malay Staff Sergeant is considered a rare species in Singapore, and is a forest-dependent butterfly. It is usually spotted singly feeding on flowers or puddling on damp sandy footpaths or streambanks.  The ripened fruits of the Singapore Rhododendron is also a favourite with this species. Interestingly, in Singapore, the females are more often encountered than the males. 

The diagnostic feature of the Malay Staff Sergeant is the twice-constricted white cell streak on the upperside of the forewing.  This streak is also well separated from the triangular spot beyond. The white bands in the males show a slight bluish tint at certain angles, but not as prominently as those in the related male Colour Sergeant.

The female is now known to be orange and black, and the differences between the female Malay Staff Sergeant and the lookalike female Colour Sergeant form-neftina are depicted in the annotated photo shown here. The female Malay Staff Sergeant is regularly observed singly, usually feeding at flowering plants or on the ripened fruits of the Singapore Rhododendron (Melastoma malabathricum)

Newly eclosed male (left) and female (right) Malay Staff Sergeant

The caterpillar host plant where it has been successfully bred on in Singapore, is Glochidion zeylanicum. The complete life history is recorded here.

Text by Khew SK : Photos by Huang CJ, Khew SK and Horace Tan

Sergeants of Singapore

The Sergeants of Singapore
Featuring the 5 Athyma species in Singapore


A female form-neftina Colour Sergeant feeds on the ripened fruit of the Straits Rhododendron

The genus Athyma comprises of butterflies with rather robust bodies and are powerful fliers. They belong to the subfamily Limetidinae of the family Nymphalidae. The butterflies have a horizontal striped appearance, usually black and white in the males, and females in some species that have the white bands replaced with either orange or brown.

A Common Sergeant (Athyma perius perius) that is no longer found in Singapore today

The are currently five extant species of the Athyma species in Singapore - often referred to as "Sergeants" by their English common names. There was a sixth species recorded from Singapore by the early authors - Common Sergeant (Athyma perius perius), but this species has not been seen in the wild for almost five or more decades in Singapore, and no longer considered an extant species here.

A male Colour Sergeant (Athyma nefte subrata) perches on a leaf

The other five "Sergeant" species continued to be regularly observed in Singapore over the years, with some more common than others. They are medium-sized butterflies with wingspans averaging between 55mm to 65mm. This blog post features all the five species and compares their differences and diagnostic features to distinguish and identify them.

The Lance Sergeant (Athyma pravara helma)

A Lance Sergeant.  Note the cell streak on the forewing which is complete and unbroken

The Lance Sergeant is the most distinctive of these black-and-white Sergeants in Singapore. The cell streak on the forewing is unbroken and club-like and this sets it apart from all the other Athymas found in Singapore.

It was a recent new discovery to Singapore, recorded in the mid-1990's and added to the Singapore Checklist. It has made a regular appearance thereafter, usually spotted when feeding on the ripened fruits of the Straits/Singapore Rhododendron (Melastoma malabathricum) and at flowering Syzygium trees.

It can be occasionally observed puddling at damp muddy footpaths in the nature reserves. The full life history has been recorded on a species of Uncaria found in the forested nature reserves of Singapore. In terms of size, the Lance Sergeant is probably the smallest of the five Athymas found in Singapore.

The Colour Sergeant (Athyma nefte subrata)

A male Colour Sergeant sunbathing. Note the blue sheen on the white bands

The Colour Sergeant is the most often seen species amongst the Athymas in Singapore. It can be observed at urban parks and gardens as well as in the nature reserves. The males are black and white striped in the usual Sergeant look, but the white stripes appear bluish when viewed with angled lighting.

A female Colour Sergeant - form-subrata

A female Colour Sergeant - form-neftina

The females of this species occur in two forms - the orange-and-black form-neftina and the brown-and-black form-subrata. The orange female form is the commoner of the two forms. The undersides are usually paler in colour with a more washed-out appearance.

A female Colour Sergeant form-neftina feeding on the ripened fruit of the Straits Rhododendron

Males are fond of perching on the top surfaces of leaves with wings opened flat, and 'attacking' intruders that wander into its space. Both sexes are often found feeding greedily on the ripened fruits of the Straits/Singapore Rhododendron.

The Dot-Dash Sergeant (Athyma kanwa kanwa)

The strange English common name of this Sergeant probably came from its cell streak which ends in a triangular 'dot'. The species is largely forest-dependent and is not often found outside the sanctuary of the nature reserves in Singapore. It is rare, and usually spotted singly.

A Dot-Dash Sergeant sunbathing with its wings opened flat.  Note the narrow cell-end streak and the sharp and angular spot at the end of the streak

A powerful flyer like its other cousins in the group, it sports the flap-glide flight characteristic of the other Sergeants. It is skittish and alert, making it a challenge to photograph it, as any slight disturbance will spook it to speed away and up to the treetops.

A puddling Dot-Dash Sergeant

The Dot-Dash Sergeant has the usual black-and-white stripes on its wings. The cell streak on the forewing above is separated from the triangular spot (which is sharp and angular). The underside is a greyish-brown.

The Malay Staff Sergeant (Athyma reta moorei)

A Malay Staff Sergeant.  Note the twice-constricted cell streak on the forewing

The Malay Staff Sergeant is probably the rarest of the genus in Singapore, and is usually observed within the forested areas in the nature reserves. As with most of its other cousins, it is usually spotted singly, either sunbathing on the tops of leaves, or feeding at flowering plants.

The species is also known to puddle at damp muddy footpaths. The distinguishing markings of the Malay Staff Sergeant is the twice constricted white cell streak and the triangular spot is separated from this streak. The triangular spot is also more rounded compared to the Dot-Dash Sergeant's sharper and angular shape.

The Studded Sergeant (Athyma asura idita)

A puddling Studded Sergeant.  Note the black centred submarginal white spots on the hindwings

The Studded Sergeant is the largest member of the Athyma genus found in Singapore. It is also a forest-dependent species but is also regularly spotted in the vicinity of mangrove areas at Pulau Ubin and Sg Buloh Wetland Reserve.

A Studded Sergeant with wings folded upright.  Note the black-centred apical spots on the forewing

The cell streak is narrow and the cell-end spot is small and rounded. The unique feature of the Studded Sergeant is the black-centred white spots at the submarginal band of the hindwing. In the local subspecies, the spots are sometimes indistinct. The apical spots on the forewing are also black-centred.

The colourful caterpillar of the Studded Sergeant

The Studded Sergeant has been locally bred on two host plants - Ilex cymosa (Aquifoliaceae), and another unidentified Ilex species in the nature reserve. The caterpillar is attractive, with bright blue spots on a green body amidst sharp spines.

A Studded Sergeant feeding at the flowers of the Mile-a-Minute weed

And there you have it, the five "Sergeants" that you can spot in Singapore. And the next time you encounter one, you can hopefully be equipped to identify which of these Sergeants that you have spotted!

Text by Khew SK : Photos by Khew SK, Koh CH, Loke PF, Nelson Ong, Jonathan Soong, Horace Tan and Anthony Wong