26 April 2020

It Takes Two! : Part 2

It Takes Two! : Part 2
a.k.a. Butterfly Sex!

A mating pair of Common Posy resting on a leaf 

In this 2nd part of the series featuring mating butterflies, we investigate the diversity of mating species amongst the remaining three families of butterflies - Riodinidae, Lycaenidae and Hesperiidae. Unlike the larger butterfly species in the previous week's blogpost, the species of these 3 families of butterflies are much smaller in size and it takes a bit of luck, opportunity and patience on the part of the butterfly photographer to shoot these mating pairs.

A mating pair of Pale Mottle with the larger female on the right

It is difficult to establish with certainty, whether the males or females of these mating pairs do the flying in the field. In our observations as recorded in the families with larger butterflies or slow flyers, we could study them as they move from perch to perch. These smaller species in the remaining three families prove slightly more challenging to follow when they are in flight.

A mating pair of Large Snow Flat, with their wings opened flat

The mating pairs of these smaller butterflies are generally more skittish, and are able to fly quite rapidly out of reach, if disturbed. Some move under leaves to hide, whilst others fly to treetop levels to get out of harm's way. However, if approached stealthily, a photographer may be able to capture a good shot of the mating pair that are undisturbed and stay still.

Family : Riodinidae

A mating pair of the Spotted Judy at Mt Faber Park

There are only 5 species in this family that are extant in Singapore. Most are relatively uncommon and at least one species, the Harlequin, is critically endangered as its local habitat where a small colony is found in, is in danger of being wiped out by development. All the other species are shy and prefer heavily shaded habitats and forested areas.

A mating pair of the Malayan Plum Judy with the male on the right

Observations of mating pairs of the Riodinidae are rare and we have on record, only the Malayan Plum Judy and Spotted Judy. They are still quite skittish even when mated and are easily spooked off when disturbed. It is difficult to say for sure whether the male or female does the flying for the pair as there have been few observation records of mating pairs.

Family : Lycaenidae Subfamilies : Curetinae, Poritiinae, Miletinae and Aphnaeinae

Mating pairs of Malayan Sunbeam (top) and Sumatran Sunbeam (bottom)

Collectively, these four subfamilies of the family Lycaenidae support a total of 13 extant species in Singapore. Of the Curetinae (or Sunbeams), there are only 2 species found here, we have had records of mating pairs of both. Both species, the Malayan Sunbeam and Sumatran Sunbeam, are moderately common with a wide distribution all over Singapore in their preferred habitats.

Mating pair of Sumatran Gem

The Sumatran Gem is the only representative of the subfamily Poritiinae which we have recorded a mating pair. Both the local species are rare and very local in distribution, preferring the heavily shaded forest understorey in the nature reserves of Singapore.

Mating pairs of the Pale Mottle (top) and Lesser Darkwing (bottom)

Amongst the seven species from the subfamily Miletinae, mating pairs of the Pale Mottle are quite regularly encountered, judging from the number of such posts on forums and butterfly groups on social media. Other species in the subfamily have occasionally been spotted mating in their preferred habitats in forested areas.

Mating pairs of Bigg's Brownwing (top) and Apefly (bottom)

The Bigg's Brownwing, Apefly and Lesser Darkwing are species that have records of mating pairs that have been encountered by butterfly photographers over the years. These are moderately common species and due to their caterpillars' carnivorous feeding habits, they are well distributed all over the island in a wide variety of habitats.

Mating pair of the Long Banded Silverline 

Of the subfamily Aphnaeinae, there are only 2 extant species in Singapore. Both species are not uncommon and can be found in habitats from urban parks and gardens to the forested nature reserves. Mating pairs are rarely encountered, but the Long Banded Silverline has been photographed mating.

Family : Lycaenidae Subfamily : Polyommatinae

This subfamily is often referred to as the "Blues", and are small delicate butterflies. Many of them have thread-like filamentous tails and are adorned with spots and streaks or iridescent tornal scales on the undersides of their hindwings. This is one of the largest group of butterflies compared to all the other families.

Mating pairs of the Grass Blues - Pygmy Grass Blue (top), Lesser Grass Blue (middle) and Pale Grass Blue (bottom)

Many of the species are very small in size, and the Pygmy Grass Blue (Zizula hylax pygmea) is the smallest species in the region. Mating pairs of the Grass Blues are not difficult to find, as they are urban butterflies and quite common. Lesser Grass Blue and Pale Grass Blue are the others that are usually encountered.

Mating pairs of the Indian Cupid (top) and the Malayan (bottom)

The rare Indian Cupid makes occasional appearances in Singapore, and then mysteriously disappears for long periods of time before showing up again. Interestingly, when they do appear, I have encountered mating pairs at least 3 times before. The Malayan, which is more common, is also featured here.

Mating pairs of Pea Blue (top), Gram Blue (middle) and Cycad Blue (bottom)

Other common species like the Pea Blue, Gram Blue and Cycad Blue are urban butterflies that can be found in our parks and gardens. These are species with long white-tipped filamentous tails and can be spotted in numbers at times, especially when their respective caterpillar host plants are abundant.

Mating pairs of Jamides and Nacaduba species

Mating pairs of the lookalike species of the genera of Jamides and Nacaduba are also regularly encountered. They are easier to photograph when mating and left undisturbed, as the species are generally active and always on the move unless feeding. Here are just a few examples of these species' mating pairs.

Mating pairs of the Two Spotted Line Blue (top) and White Fourline Blue (bottom)

Of special note are the Two Spotted Line Blue (Nacaduba biocellata) which is an exotic species of Australian origin. This species is very seasonal, where it appears in large numbers at certain times of the year and then disappearing altogether until the next outbreak. The next one is the White Fourline Blue (Nacaduba angusta kerriana) which is very rare, and only appearing for a short period and even was "common" for a short period of time when we were able to record its life history.

Family : Lycaenidae Subfamily : Theclinae

A mating pair of Green Imperial

The next large group of butterflies from the sub-family Theclinae features small, but robust-bodied, swift-flying species. The sub-family is also known for a number of spectacular long-tailed butterflies, of which many are forest-dependent species.

Mating pairs of various Theclinae species

Some are very rare and seldom seen, much less a mating pair! A photographer must be very lucky to see mating pairs of these species, like Semanga superba deliciosa, Scarce Silverstreak, Ambon Onyx and Acacia Blue. This is because the males of these species tend to stay more often at the treetops and the majority of individuals spotted are usually females.

Some long-tailed mating pairs - Branded Imperial (top), Common Imperial (middle) and Common Posy (bottom)

The long-tailed beauties like the Branded Imperial, Common Imperial, Green Imperial and Common Posy are more usually encountered in the forested areas of Singapore. But occasionally, mating pairs are spotted and provides good opportunities to photograph them in ideal environments with good composition and background.

Family : Hesperiidae Subfamily : Pyrginae

A mating pair of the Large Snow Flat

We come to the last of the six butterfly families in Singapore, the Hesperiidae or Skippers. The first sub-family Coeliadinae has very few records of mating pairs and are thus not featured here. The next sub-family, Pyrginae (or Flats) are represented by 12 species extant in Singapore. Thus far, only two species have been spotted as mating pairs, although others have been seen, but not photographed.

A mating pair of the Hieroglyphic Flat

Of the two species, the Hieroglyphic Flat has had a few occasions where mating pairs were spotted. This iconic butterfly is one of the prettiest skippers found here in Singapore. The other "Flat" which has a photographic records of mating pairs is the Large Snow Flat. Note that even when mating, the species are seen with their wings opened flat.

Family : Hesperiidae Subfamily : Hesperiinae

A mating pair of Bengal Swift

The final sub-family Hesperiinae features over 50 species extant in Singapore, and counting. Many of the species are cryptic and appear irritatingly similar to each other, making identification in the field very challenging. Coupled with their variability, in-species variability in markings and male-female differences, the Hesperiinae needs more research into their identifications.

Mating pairs of various skippers - Dark Banded Ace (top), Chestnut Bob (middle) and Grass Demon (bottom)

Mating pairs of the rare Dark Banded Ace (Halpe ormenes vilasina) have turned up once in a while, whilst the common Chestnut Bob, Banded Demon and Grass Demon mating pairs do show up more often. Even so, some of them are still as skittish and hard to photograph in the field when they are not in a cooperative mood to be photographed.

Mating pair of Banded Demon

Mating pair of the sexually dimorphic Quedara monteithi monteithi - the all-brown male is on the right, whilst the white banded female is on the left

A rare encounter with the sexually-dimorphic Quedara monteithi monteithi's mating pair shows very clearly the male-female differences. However, mating pairs of the more common Small Branded Swift and Contiguous Swift turn up more regularly, but harder to distinguish, as the sexes are almost identical.

Mating pairs from the genera Taractrocera (top), Potanthus (middle) and Telicota (bottom)

Of the last few genera of the orange-black species from Taractrocera, Potanthus and Telicota, photographs of mating pairs turn up once in a while, especially of the more common species extant in Singapore. The photos featured here are not exhaustive.

Mating pair of the Lesser Dart

And there you have it, a series of photographs of butterflies procreating, compiled from the creative works of many butterfly photographers over the years. There is no doubt that there will be more species recorded in the coming years as more and more photographers who are spending more time out in the field will surely encounter these paired butterflies.

Text by Khew SK : Photos by Sunny Chir, Chng CK, Antonio Giudici, Huang CJ, Khew SK, Koh CH, Lim CA, Loh MY, Loke PF, Neo TP, Richard Ong, Simon Sng, Tan BJ, Bene Tay, Tea YK, Anthony Wong, Mark Wong and Siaomouse Wong

It Takes Two! : Part 1

19 April 2020

It Takes Two! : Part 1

It Takes Two! : Part 1 
a.k.a. Butterfly Sex!

A mating pair of Leopard Lacewing holding on to a vine

Now that I have caught your attention with the 'S' word, please read on... But before anyone goes off to report this site for featuring undesirable material, let me assure you that this remains a family-friendly blog. Butterflies, like in most species in our animal kingdom, procreation is one of the main objectives of survival, and the need to continue the sustainability of the species line for generations. So perhaps it is a good time to reflect on the birds and the bees, and throw in some butterflies for good measure.

A mating pair of White Kite/Taiwan Tree Nymph (not a native species of Singapore, but can previously be seen at the Sentosa Butterfly Park or the Singapore Zoo)

Unless a species or organism is a hermaphrodite or one that can switch sexes at different stages in their life history for autonomous reproduction, most other species in the animal kingdom is divided by the gender of male or female. We have previously discussed some aspects of butterfly courtship rituals before a successful mating is achieved.

A mating pair of Common Mormons with the female form-polytes above

During this period of global chaos caused by the COVID-19 pandemic and various countries' lock-downs, quarantines and Singapore's own 'circuit breaker' measures, many of us sit at home and try to find ways and means to pass the time. Working, learning and social interaction in the virtual space has become a norm for some of us over the past few weeks. So I spent some time digging out old photos from various archives.

A mating pair of Blue Pansy with the female above

This weekend's blogpost features the work of many accomplished butterfly photographers in Singapore, showcasing mating pairs of butterflies. Whilst I was searching our repositories of butterfly photos from our forums, social media and archives, I was amazed at the number of species that we have photographed of mating butterflies. Very often, skittish species are more cooperative and easier to photograph when they are otherwise distracted by other more pressing activities. And whilst no butterflies were harmed in the photography, some may have thought that we photographers have invaded their privacy!

A mating pair of Clippers (not native in Singapore) but recorded on the Singapore checklist through a single vagrant individual spotted in the wild

However, in admiring these photographs, butterfly observers should also consider the following and take stock of what they can remember when they encounter mating pairs :
  • Obviously, both individuals cannot fly at the same time. Hence, was it the female that was doing all the flying and carrying the weight of both, or was it the male?
  • How far can they fly, considering that they were carrying twice their normal weight?
  • Did they do anything to protect themselves from predation whilst in this vulnerable position?
  • How long did they stay connected? And which of the two that initiated the disengagement? (Butterfly biology suggests that the male has control of the mating process because its claspers hold on to the female and it decides when to release the female. But in the field, is this always the case?)
  • When they stopped to rest on a perch, did their wings remain closed or open?
In this two-part series, we will showcase species from the six families of butterflies and pairs of butterflies caught in flagrante delicto - mostly around various habitats in Singapore. We will start with the largest species in Singapore, from the family Papilionidae (Birdwings and Swallowtails).

Family : Papilionidae

A mating pair of Great Mormon, with the female f-butlerianus at the top

Amongst these spectacular and large butterflies, the females are generally larger, with a greater wing surface area than the males. From many of our mating pair shots, it was also observed that the females did all the flying and carried the weight of both whilst mating. The clues to this observation (besides watching them fly through field observations), are that the female is the one that is perched or holding on to the perch. But these are just generalisations that are not necessarily 100% accurate or validated by research.

From the large Common Birdwing to the Great Mormon and Great Helen, it is observed that the larger female with a greater lift capability carried the pair when mated. For these bigger species, they are more clumsy when flying, and tend to stop more often to conserve their energy. Maneuverability is a challenge as they will knock into leaves and branches when flying, unlike the smaller butterflies.

Mating pairs of Common Jay (left) and Tailed Jay (right)

A mating pair of the Great Helen, with the female on top

For the faster flying and more skittish species like the Graphiums and Papilios it is also usually the females that do the flying for the pair. However, they are harder to photograph, as they tend to continue flying when threatened and are able to fly to higher perches, out of reach of the photographer.

Mating pairs of Common Mormon (left) and Lime Butterfly (right)

Mating pairs of the common urban species like the Lime Butterfly and Common Mormon are also encountered regularly. Usually fast flying and restless, photographing these species becomes less challenging when a mating pair is encountered.

Family : Pieridae

We move next to the family Pieridae (Whites and Sulphurs). The flight speed of the species in this family ranges from very fast to slow. Amongst the fast flyers like the Mottled Emigrant, Striped Albatross and Orange Emigrant, field observations indicate that the males tend to do the flying when the pair is mated. Anecdotal evidence shows that the males choose the perch to rest on, and is the one determining the mobility of the pair, whilst the females tend to remain stationary.

Mating pairs of Mottled Emigrant (top), Striped Albatross (middle) and Orange Emigrant (bottom)

Field observations also show that in some of these species, when a pair is mated, there is often another male trying to elbow in on the action and disturbing the mating pair to break off. However, in most cases, the intruding suitor was unsuccessful in disengaging the mating pair.

Mating pairs of Cabbage White (left) and Psyche (right)

It appears to be the same for the slower flying species in the family, like the Psyche, Cabbage White, Grass Yellows and Painted Jezebel. Due to their relative similarity in size, there is no clear advantage that the females have over the males in terms of the ability to carry the weight of both butterflies when one of them has to do the flying for both.

Family : Nymphalidae Subfamily : Danainae

Mating pair of Plain Tiger with the male at the top

The diversity of species across the different sub-families of these "Brush Footed" butterflies is very wide. Let us start with the sub-family Danainae of Crows and Tigers. These relatively large, slow flying butterflies, particularly the more abundant Plain Tiger, Common Tiger, Black Veined Tiger and the various Glassy Tigers have often been 'captured' whilst mating.

There does not appear to be a consistent pattern of which of the two sexes that does the flying. Although in the handful of cases where I have personally encountered mating pairs, it was the male that tends to do the flying.

Mating pairs of Blue Glassy Tiger (top) and Black Veined Tiger (bottom) with the males holding on to the perch

The presence of key characteristics to separate between the males and females of Danainaes help to determine which of the two sexes is the "dominant" one that does the flying and maneuvering of the pair. In some of my field observations, the male does make attempts to conceal themselves by flying up high, or try to perch amongst branches and leaves that may obstruct any attack on them. However, being distasteful to predators, I wonder why they needed to do that?

Family : Nymphalidae Subfamily : Satyrinae

Mating pairs of Dark Brand Bush Brown (top), Dark Grass Brown (middle) and Burmese Bush Brown (bottom)

Many of the species in this subfamily of Browns and Arguses tend to favour shaded habitats and fly amongst low grasses. Of these, the Bush Browns (Mycalesis) and Rings (Ypthima) are the most often encountered whilst mating. Again, there is no consistency from our observations whether the male or female does the flying when mated. Also, due to their similarity in size and appearance, it is not often easy to distinguish between the pair.

A set of mating pairs of the Common 3, 4 and 5 Rings and Malayan 5 Ring

When mated, many of our photographs depict the mating pair as "equals" - both holding on to the perch they are resting upon. In some of the cases which I have come across, the female did all the flying. However, they are skittish, and tried their best to stay out of sight when intruded upon.

Mating pairs of Common Palmfly (top) and Common Evening Brown (bottom)

Amongst the larger Satyrinaes like the Common Palmfly and the Common Evening Brown, the slightly larger females are the "dominant" species when it comes to the mobility of the pair. They are also quite alert and will try to hide amongst obstacles when disturbed.

Family : Nymphalidae : Subfamilies : Charaxinae, Heliconiinae, Limenitidinae and Nymphalinae

The next group of mating pairs involves species that fall in various subfamilies, ranging from common to rare. In some cases, the sexual dimorphism is very distinct and females may be even 10-20% larger than the males. In these instances, it is quite obvious that the greater lifting power of the larger females gives her the advantage to do the flying for the pair.

A mating pair of Plain Nawab

Species such as the Plain Nawab, whose caterpillars are more often seen in our nature parks and gardens, are rarely seen as a mating pair. The chance encounter of this pair seen at the old Alexandra Hospital Butterfly Trail was the only time I have observed them mating.

Two mating pairs of naturalised exotic species - Leopard Lacewing (left) and Tawny Coster (right)

The Leopard Lacewing, a non-native that has since been naturalised in Singapore, is quite regularly seen mating, particularly in butterfly parks and enclosures. Another exotic, the Tawny Coster, also common in Singapore today, can regularly be encountered as a mating pair in the field. From the many shots of mating pairs posted in forums and social media groups, this is probably the case.

Mating pairs of Burmese Sailor (top), Short Banded Sailor (middle) and Malayan Lascar (bottom)

Amongst the Limenitidinae, the Sailors and Lascars have regularly been spotted mating. These species are usually skittish and difficult to photograph. However, when mating, they continue to be very alert and often fly off to inaccessible perches to continue with their business in privacy.

Mating pairs of Horsfield's Baron (top) and Malay Baron (bottom)

The larger females of the Barons, Dukes and Viscounts, all from the genera Euthalia, Tanaecia and Lexias, the distinctly larger and sexually dimorphic females (in some of the species) make photographing a mating pair quite interesting. The marked difference in the males and females of these genera display the obvious diversity between the sexes.

Mating pairs of Chocolate Pansy (top), Great Eggfly (middle) and Malayan Eggfly (bottom)

This is also similarly observed amongst the Nymphalinae, where the dimorphism and differences in colours, patterns and markings between the males and females are brought out in photographs of mating pairs.

Mating pair of Royal Assyrian

And there you have it, some examples of mating pairs of butterflies. In our next part, we will take a look at the remaining 3 families of butterflies found in Singapore. To all our readers around the world in this current pandemic, stay safe, stay healthy and stay home!

Text by Khew SK : Photos by May Chan, Antonio Giudici, Huang CJ, KhewSK,  Michael Khor, Koh CH, Lim CA, Loh MY,Nelson Ong, Terry Ong, Michael Soh, Horace Tan, Tan BJ, Tea Yi Kai and Anthony Wong