Butterfly of the Month - April 2019

Butterfly of the Month - April 2019
The Common Faun (Faunis canens arcesilas)


A Common Faun perches on a leaf under the shady forest canopy

Spring is in the air. This is the time for the ethereal atmosphere of blooming pink flowers like the well-known Sakura season in Japan. Whilst Singapore doesn't have naturally-growing Cherry blossoms lining our parks and gardens, the change in weather from hot/dry to the April showers triggered off our own blooming of sorts in this City in a Garden.

The Trumpet Trees (Tabebuia rosea) in various parts of the island, with their crowns of pink flowers were reminescent of the Japanese cherry blossom flowers (without having to fork out the air fare to fly to Japan to experience it). Alternatively, visit the Gardens by the Bay for a slightly more "authentic" experience of the sakura blooms without the expense to boot!

Great Wall of China surrounded by pink cherry blossoms - Mar 2019

My first trip to the Great Wall of China, when I had an afternoon of spare time, was also augmented with pretty-in-pink blooms of the cherry blossoms surrounding China's modern 7 Wonders of the World. At this location near Beijing, the cool weather and off-peak season (i.e. less crowded!) allowed a leisurely stroll up a few hundred metres of this historic wall of ancient China.

Very much in the news during this month was the crash of Ethiopian Airlines' flight ET302 and similarity of the crash with LionAir's flight JT610 just 5 months earlier. Both Airlines were using new Boeing 737 Max planes and investigations have pointed to a problem with the flight stabilisation system designed to prevent stalling - the maneuvering characteristics augmentation system or MCAS. Basically, the automated system on the plane erroneously controlled the plane's flight and attempts by the pilots to override the system failed, causing the planes to nosedive into the ground, just minutes after take-off.




As humans continue to depend more and more on technology in our everyday lives, software design comes into question when we have to deal with autonomous transportation modes and leaving ourselves at the mercy of technology. A recent example was when I saw a driver smash her car into a barrier in a carpark whilst reversing. When I helped to pacify the lady driver on her smashed car, I asked her why she didn't stop the car when she knew that there was a barrier behind her? Her reply was that the sensor in her car did not beep to indicate that she needed to stop!



An interesting episode of how dependent that we have become on technology and sensors, such that our "everything automatic" expectations have made us forget how to use our eyes and ears and apply situational awareness when we drive or operate any mechanical device? Some food for thought...


A Common Faun feeding on rotting fig fruit on the forest floor

Our Butterfly of the Month for April 2019 is the shade-loving Common Faun (Faunis canens arcesilas). A medium-sized butterfly with a wingspan of about 60-65mm, the Common Faun is a forest-dependent species that rarely leaves the sanctuary of the heavily-shaded forested areas in Singapore.




The English common name of "faun" is interesting, as it has its origins in Greek mythology. A faun is a half-human, half-goat creature in the enchanted forests of Rome. It is a two-legged creature, with the legs and tail of a goat, and the torso, arms and horned head of a man. Legend has it that fauns inspired fear amongst travellers in lonely, remote or wild places in the forests.


Very rarely, the Common Faun may be observed to open its wings to sunbathe in sunlit spots in the shady forest understorey

In reality, our shy Common Faun is probably only associated with shady quiet forests in our nature reserves. It is a relatively common butterfly, usually foraging amongst the leaf litter in the understorey of forested areas. It flies close to the ground, often no more than a metre above the cluttered forest floor. It is well camouflaged as it feeds on overripe fruits and other organic matter on the forest floor.



The Common Faun is orange-brown and unmarked on the upper side of both wings, with a slight darker shading on the termen from the apical area to the tornus of the forewing. The underside is dark brown with a series of squiggly transverse lines across both wings. In a sidelight, the underside of the hindwing may have a purplish hue. There is a series of submarginal white dots on both wings. The eyes are deep green.



The brown underside of the Common Faun camouflages it well when it forages for food amongst the leaf litter on the forest floor

The butterfly is often encountered along forest paths, lurking amongst dead leaves and twigs. It usually stops with its wings folded upright, where it merges well with the leaf litter on the ground. It can be quite skittish and difficult to approach when it is alert. However, when disturbed it does not fly very far before it stops and tries to camouflage itself on the forest floor.


An open-winged Common Faun feeding on a rotting fig fruit on the forest floor

The Common Faun is observed to feed on overripe fruits and other rotting matter on the forest floor. A favourite is the fruit of various species of figs (Ficus spp.) that fall on the forest floor. It can also be baited with overripe banana, papaya and mango, as with some of the other fruit-feeding butterflies in the forests.


A female Common Faun oviposits on the underside of a leaf of its caterpillar host plant, the Fishtail Palm

The species' caterpillars feed on Fishtail Palm (Caryota mitis) and probably other species of palms. The caterpillars are hairy and resemble moth caterpillars. They feed in groups and stay together until it is time to pupate, where each individual then moves away from the host plant and pupates under a leaf.

Text by Khew SK : Photos by Chng CK, Khew SK, Koh CH, Loke PF, Nona Ooi, Michael Soh, Anthony Wong and Benjamin Yam.

The Butterfly Legs

The Butterfly Legs

An Anatomical Discussion of the Legs of a Butterfly


A Common Mormon tiptoes on its slender long legs as it puddles on damp sand

Insects form the largest group within the phylum arthropoda. In general, insects have a chitinous exoskeleton, a body that has 3 distinct segments (head, thorax and abdomen), three pairs of jointed legs, compound eyes and one pair of antennae. Butterflies belong to the Order Lepidoptera (Scaled wings) and are classified as insects.

A Painted Jezebel uses all its six legs to grasp the flower as it feeds on nectar

Fundamentally, this means that all butterflies have six legs. However, even though all six legs are present, the forelegs of some butterfly species have evolved and adapted to perform a totally different function from their original purpose of locomotion (walking). In particular, the species in the family Nymphalidae or often referred to as "Brushfoot" butterflies, have their forelegs reduced to such an extent that they become imperfect and brush-like (hence the name brushfoot) and useless for walking.

A typical butterfly leg has the following five parts, in sequence, from where the leg is attached to the thorax to the extremities (usually the tarsal claws) - coxa, trochanter, femur, tibia and tarsal segments. Butterflies have three pairs of legs - the forelegs (nearest to the head), the middle legs and the hind legs, each attached to a segment of the thorax.

Although each typical leg consists of the standard segmented parts, there is a wide variation of the legs across the butterfly families. This blog article takes a look at some of the differences of the butterfly species' legs from different families. The majority of the photos depicted here are cropped from a full frame DSLR sensor output and may not be as sharp or of high quality as expected.

Papilionidae

Papilionidae species have long slender legs that allows the butterfly to "stand tall"

All six legs are present in all the species of the Papilionidae family. A typical Papilionid has the longest legs (measured from coxa to tarsus) compared to the species in other families. The femur of the Papilionid's leg appears more 'muscular' compared to species of other families. The tarsal segments are typically long and when a Papilionid butterfly puddles or uses its legs to hold onto a flower as it feeds, the body of the butterfly is held high and some distance away from the food source.

A Lime Butterfly uses its sharp tarsal claws to grasp its perch as it stops to rest

A Five Bar Swordtail's legs in close up.  Note the greenish hue and sharp spiny hairs on its legs

Most Papiliond species have tibia spurs and the femur, tibia and tarsal segments may be covered with small spiny hairs which aid in holding on to perches and help in gripping onto flowers as the butterfly feeds. The tarsal claws are prominent on all the legs and also help to hold on to branches, leaves and any other perch that the butterfly is resting on.

Pieridae

All Pieridae species have six legs fully developed and functional. Many of the species usually have their legs concolourous with the butterflies' abdomen or wings. There is usually a darker longitudinal stripe throughout the length of the leg. Compared to the Papilionidae, the Pierids have shorter legs. The femur is usually covered with short and soft hairs.


Pieridae have all six legs developed

As with the other species, the Pierids have tarsal claws and fine hairs on the tarsal area of the leg to help it hold on to its perch whilst it stops to rest or when feeding. They usually utilise all six legs to grasp the perch or balance on a flower.

Nymphalidae

An Autumn Leaf perches with its four legs and balances well with its legs spread out

The Nymphalidae family (or Brushfoots) are unique in that the forelegs of the butterfly species in this family are under-developed and reduced to mere tufts of hair. These 'legs' are therefore are useless and unfunctional. Most of the time, these forelegs cannot be seen, whilst the middle and hindlegs are well developed and robust. The butterfly species in this family appear to have only 4 legs.


A Common Tiger uses its sharp tarsal claws to clutch onto a flower as it feeds on the nectar


A Blue Pansy perched on a flower on its four legs.  Note the sharp spiny hairs on its legs

The variety of species in the sub-families Danainae, Satyrinae, Nymphalinae and so on clearly show that they are not in any way disadvantaged with only 4 legs. They go about their usual daily routine using just the remaining 4 legs (middle and hind legs) without any problems at all.

Riodinidae

A Female Harlequin has all six legs developed.

The Riodinids are unique in that only the females have six fully developed legs. In the males, the forelegs are reduced to tufts of hair like in the Nymphalidae and these legs are not functional. However, the females tend to fold their forelegs tightly to the front of the thorax and appear to also have only 4 legs to stand on.


A male Harlequin has four developed legs whilst its forelegs are reduced to just tufts of hair

The legs of the Riodinids are relatively short and thick with the tarsal segments, particularly at the extremities close together giving them a banded appearance. The legs of the Riodinids also appear to lack the prominent tibia spur that can be found in other species of butterflies.

Lycaenidae

A Blue Brownwing's unique shaped legs. Note the compressed tarsal segments of its foreleg


A Bigg's Brownwing with its rather specialised foreleg that appears spatulate and flat

The variety of leg designs across the many genera of Lycaenidae is quite amazing. Of special note are the legs of some species of sub-family Miletinae. Of interest are the legs of the Miletus spp. The legs appear flattened and taper towards the joints. The tarsal are broader towards the extremities and as least in one of the species, the forelegs appear to lack the tarsal claws.





A variety of six-legged Theclinae with banded and pure white legs

In other species of the subfamily Theclinae, the legs are short and thick, and may sometimes be black and white banded. In other species, all six legs appear as if they are clad in white stockings. The tibia spur occur in many species across the family and the tarsus is also covered with small spiny hairs which allow the butterfly to hold on to its perch firmly.

Hesperiidae

Note the exceptionally hairy femur and tibia of some Hesperiidae species

The Skippers have all six legs fully developed. In many of the species, the femur is exceptionally hairy and covered with thick long hairs, giving this segment of the leg a rather thick and muscular appearance. In some species, the hairs extend to the next segment, the tibia. The tibia spurs are thick and prominent. On the hind legs, there is usually an additional pair of tibia spurs in a number of species.


The White Banded Flat has evolved a rather strange tuft of hair on the tibia of its hind legs

In some unique species, like the White Banded Flat, the hind legs are further evolved to have a prominent hair tuft covering the tibia and extending beyond the leg.

So the next time you have an opportunity to observe a butterfly closely, take a look at its legs and see what interesting observations you can make about the legs of different species of butterflies.

Text by Khew SK : Photos by Huang CJ and Khew SK

Three Archdukes

Three Archdukes
Singapore's Archduke butterfly species


A male Archduke foraging amongst the leaf litter in the shaded forest understorey

In my earlier article on this blog, I postulated that the English common naming convention of butterflies could have been possibly coined after the titles of English peerage or Imperial gentry and military ranks. In this article, we take a look at the Archduke butterfly species that can be found in Singapore.


A female Dark Archduke on leaf litter 

Unlike the English peerage titles, the Archduke (feminine: Archduchess) was a title that originated from the Habsburg rulers of the Archduchy of Austria. It denotes a rank within the former Holy Roman Empire, which sat just below that of Emperor and King.


Hierarchy of titles in Imperial, royal, noble, gentry and chivalric ranks © Wikipedia

The etymology of the word Archduke originates from various European languages and purportedly signifies authority or primary (Arch) and leader (Duke). Notwithstanding the historical origins of the royalty-linked name, the Archduke butterflies are no less majestic in their size and prominence in the butterfly world, befitting of their common name.


A Yellow Archduke perches on a leaf in the forested nature reserves

There are 3 extant species of Archdukes that can be found in Singapore. Belonging to the genus Lexias, which features large, robust-bodied and fast-flying butterflies that prefer the heavily shaded forests rather than open sunny areas. All are considered forest-dependent and not found in urban parks and gardens. They are usually found foraging for over-ripened fruits and feeding amongst the leaf litter on forest paths.

The Archduke (Lexias pardalis dirteana)



Upperside and underside of a male Archduke

The commonest species of the genus, the Archduke displays sexual dimorphism in that the male is physically very different from the female. The male is dark velvety black above with a broad blue hindwing border, which is continued (usually in a lighter shade) along the termen of the forewing. The underside is a deep reddish brown with yellow spots.



Upperside and underside of a female Archduke

The female is dark brown above, with prominent yellow spots on both wings, including the body of the butterfly. The underside is a light brown with the yellow spots showing through. The hindwing is a pale-greyish blue throughout.



Note the bright orange apical tip of the Archdukes' antennae

In both sexes, the apical portion on the topside of the antennae is prominently orange. The orange colour is continued on the underside of the antennae as well. This is the most reliable distinguishing characteristic that separates the Archduke from its very closely related Dark Archduke.

The Dark Archduke (Lexias dirtea merguia)


A male Dark Archduke on leaf litter

Almost identical to the Archduke, the Dark Archduke (previously called the Dark-Tipped Archduke), is also sexually dimorphic, with the male and female's appearance corresponding to the Archduke. The habit of this species mirrors the Archduke, and individuals are often found feeding on rotting fruit and other organic matter amongst leaf litter on the forest floor.



Upperside and underside of a female Dark Archduke

The male and female of the Dark Archduke closely resemble the corresponding sexes of the Archduke. The male is velvety black above with the blue marginal border on the hindwing, which extends to the termen of the forewing. The female is dark brown with yellow spots on both wings.



Note the black antennal tips of the Dark Archduke male and female

The primary difference between the Archduke and Dark Archduke is that the apical portion of the antennal club is black instead of orange. The underside of the antennae can still show some orange colouration like the Archduke. It is almost impossible to distinguish the two species when in flight, although there are some key, but still variable differences on the wings of both species to help distinguish them.

The Yellow Archduke (Lexias canescens pardalina)


Yellow Archduke puddling on the forest floor

The third, and smallest species of the three Archdukes is the Yellow Archduke. Of great interest is that it is the only species in the Lexias genus that is not sexually dimorphic! Both the male and female look alike, although the female is usually much larger. Displaying the same forest-floor foraging habits as its two other cousins, it is also a forest-dependent species.



Upperside and underside of the Yellow Archduke

The Yellow Archduke is dark brown above with large yellow spots on both wings, resembling the females of the Archduke and Dark Archduke. However, both the males and females look alike. The underside of the hindwing only has the dorsal margin a pale-greyish blue with the larger part of the wing brown and yellow.



Mating pair of the Yellow Archduke

On the upperside of the forewing, the line of yellow spots at the post-basal area features a spot (the 4th spot from the base) which is coalesced into a single spot. In the female Archduke and Dark Archduke, this yellow spot is split into two spots. This is the most reliable characteristic to separate the Yellow Archduke from its two close cousins.

Text by Khew SK : Photos by Khew SK, Koh CH, Nelson Ong, Simon Sng and Jonathan Soong