14 December 2019

Butterfly of the Month - December 2019

Butterfly of the Month - December 2019
The Yellow Archduke (Lexias canescens pardalina)

A Yellow Archduke foraging amongst the leaf litter along a shaded forest path

And we reach December 2019, the final month of the 10-year period starting from 2010, we stand on the threshold of 2020 and an exciting new decade ahead. The world is changing at an even faster rate, with unprecedented technological disruptions, new experiences and a new way of life that we would never have dreamed of in the 20th century.

In the developed and emerging economies of the world, it would be hard to imagine life without the ubiquitous smartphone that has penetrated every aspect of our daily lives. It is this "computer in our hands" that has accelerated so many changes in our our lives, from ordering food to daily mobility and consuming information and news. Today, it is almost unthinkable that there are still people around who does not carry a smartphone - so dependent are we on it.

A Yellow Archduke sunbathing on a patch of leaves

And then comes AI or Artificial Intelligence, which is developing so rapidly that it is beginning to make Skynet (of the Terminator movies) somewhat a reality rather than fiction. Today, we hear possibilities of unmanned vehicles, unmanned stores, unmanned banks and unmanned schools? One begins to wonder what the world will be like in 2100?

The subject of environmental issues and climate change will be more and more actively debated. Countries that have the means, are already looking at how they can protect themselves from the adverse effects of climate change, whilst there are some that ignore the signs or are just too helpless to do anything effective. But this is a global issue and not a geographical nor political one. After all, don't we all breathe in the same air everywhere we go and it's not air that belongs to only one country?

Some newsworthy items in Singapore include the decision to put the mass transit Cross Island Line right below the nature reserve. Whilst it sparked off a huge debate when it was first announced, the nature community engaged the authorities to try to find a middle ground. Although the outcome will not satisfy everyone, the optimists will conclude that at least the authorities have compromised and found mitigation measures to reduce the environmental impact of the construction of this mega transportation project across a "nature reserve".

When PMDs (electric personal mobility devices) came into the environment and shared transportation networks with pedestrians, there are bound to be unfortunate interactions that neither side will find acceptable. However, it had to take several fatal accidents and lives lost, before the authorities took decisive action to ban them from shared pedestrian footpaths. And then the extent of the use of these devices in the food delivery business became obvious, as livelihood issues were raised. The problems of a developed and techology-dependent world!

Our final butterfly of the month for this decade is a medium-sized forest-dependent species called the Yellow Archduke (Lexias canescens pardalina). One of three Singapore-extant species from the genus Lexias, the Yellow Archduke is rather local in distribution and the rarest of the species found in Singapore.

A Yellow Archduke perched on a leaf 

The Yellow Archduke is an interesting species in that both the males and females are similar in appearance, but both look like the females of its related species, the Archduke and Dark Archduke. This often creates a confusion in the identification of the species, especially when all three can be found in the same habitats - in the shaded forest understorey of the nature reserves in Singapore.

A mating pair of Yellow Archdukes

The species is usually encountered foraging on forest litter and overripe fruits on the forest floor. At its preferred habitats, sometimes several individuals may be found together, and engaging in "dogfights" just a few feet above the forest floor. They are skittish and alert to movement, making them rather hard to approach for a photo. At times, when they are feeding greedily, they may be sufficiently distracted to allow an observer to approach them without scaring them off.

The Yellow Archduke is generally smaller in size, but is similarly marked as the females of the Archduke and Dark Archduke. Males and females are similar in appearance, except that the males are usually smaller in size. The species is dark brown above, with yellow spots on both the fore and hindwings.

A Yellow Archduke showing its undersides whilst foraging amongst leaf litter

The underside is a deep ochreous brown with yellow spots. Only the basal area of the hindwing is pale greyish blue, unlike the females of the Archduke and Dark Archduke, where almost the underside of the entire hindwing is pale greyish blue.

A weathered Yellow Archduke puddling along a muddy footpath

A Yellow Archduke feeding on ripened berries on the forest floor

Besides the underside of the hindwing, one of the most obvious diagnostic feature of the Yellow Archduke, is the 3rd spot from the base in space 1b of the forewing. This spot is coalesced into a single spot, whereas it is split into two spots in the female of the Archduke and Dark Archduke.

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

08 December 2019

Butterfly Eyespots

Butterfly Eyespots
Ocelli on A Butterfly's Wings

An eyespot on a butterfly's wing, complete with "pupil and iris", and a reflective highlight - all created by the evolutionary adaptation of the scales on the wings

The intricate patterns, markings and colours of a butterfly's wings have long intrigued researchers, many of whom have postulated theories and possible reasons for these markings. Whether these are striations, bands, structural colours, iridescent markings or eyespots, their functional origins or objectives have often been a source of debate amongst scientists.

A female Blue Pansy (Junonia orithya wallacei) complete with colourful "eyes" on the fore and hindwings

The amazing array of designs and spectrum of colours on a butterfly's wings have been admired by nature enthusiasts and butterfly watchers. From black-and-white patterns to multi-coloured designs, each species of butterfly is unique in its own right. Combined with the morphological attributes of wingshape, size and so on, these features are often used for the basic identification of the different species of butterflies.

Underside ocelli of the Blue Morpho (Morphos peleides

Other than just for pure aesthetic reasons to look 'pretty', observers and scientists have been searching for answers as to why the patterns and colours on butterflies' wings are presented in such a way and if there are evolutionary functions of these patterns and markings, whether viewed individually or as a group, to resemble or mimic other organisms.

The large eyespots on the Giant Owl (Caligo memnon) are designed to confuse predators that they are dealing with an animal that is much larger

One of the often-studied features of a butterfly's wing patterns is the presence of ocelli (singular : ocellus) or referred to as "eyespots" on the wings. Eyespots may be a form of mimicry in which a spot on the wings of a butterfly may resemble an eye of a much larger animal to deceive potential predator or prey species. Eyespots may also play a role in intraspecies communication or even in courtship.

The modified ocelli at the tornal area of the hindwing of the Long Banded Silverline, complete with false antennae moving in the wind, are designed to fool predators into attacking a less critical part of the wings

In some cases, like in Lycaenidae species, the eye spots are a form of self-mimicry, to draw a predator's attention away from the most vulnerable body parts. Coupled with striations which draw attention to the eyespots and the butterfly's wing movements, this form of decoy mimicry has been well studied.

Large tornal "eyes" on a Great Helen's hindwings with its spatulate tails - designed to confuse predators?

Let us take a look at some examples of ocelli-adorned species across the different families of butterflies in Singapore. The Papilionidae do not generally employ ocelli patterns on the majority of the species in the family. A few species like the Helens and Great Mormons feature large tornal ocelli that suggest that these eyespots may be some form of decoy that could either scare predators into thinking that they are dealing with a large animal with red eyes, or perhaps direct a predator to a less fatal spot to attack.

An eyespot on the underside of a Lime Butterfly.  A mere decorative feature, or an eyespot designed to confuse predators?

The Pieridae species of "Whites and Sulphurs" have wings that feature streaks, spots and stripes, but have no particular strong association with the use of ocelli for any form of mimicry or protection. Many of the species of this family display aposematic colouration or simply use their flight speed to avoid predators.

Amongst the subfamilies of the family Nymphalidae, the use of ocelli-like patterns on the wings appear to be mainly limited to the subfamilies Satyrinae and some genera of Nymphalinae. The other subfamilies are generally patterned with stripes and other forms of designs, and usually coloured beautifully.

Eyespots on the wings of the Bush Browns (Mycalesis spp) complete with "irises and pupils"

The Satyrinae in particular, have several genera that have wings adorned with ocelli, e.g. Orsotriaena, Mycalesis, Ypthima, and many others. With the majority of the species in the subfamily that are not known to be distasteful to predators, it is likely that the use of ocelli on their wings give some measure of mimetic decoy as protection from predators.

Ocelli on the hindwing of Ypthima species

The Mycalesis or Bush Browns, and the Ypthima or Rings, have many ocelli on their fore-and hindwings as well as on the uppersides and undersides of their wings. Whether these eyespots are meant to intimidate, confuse or misdirect predators would be an interesting subject for researchers to further investigate.

"I'm looking at you!" - Eyespots on the hindwing of a Palm King (Amathusia phidippus)

Amongst the larger species of butterflies, formerly placed in the Morphinae subfamily, are also examples that feature large animal-like eyespots, particularly on the undersides of the wings. These species tend to lurk in the shaded understorey of forested areas and camouflage themselves well. These eyespots may fool predators into thinking that they are dealing with a larger animal.

© Vallin A1, Jakobsson S, Lind J, Wiklund C : From the research article : Prey survival by predator intimidation: an experimental study of peacock butterfly defence against blue tits.Biological Sciences, 01 Jun 2005, 272(1569):1203-1207

The studies of ocelli and their effect on predation have been largely done by western researchers and the experiments conducted by the Swedish researchers, particularly on the European Peacock butterfly (Inachis io) have produced evidence that these eyespots do deter predators like birds from attacking the butterflies. Essentially, the researchers painted over the ocelli for some of the butterflies and studied them together with the normal individuals and how predators react to them.

Colourful eyespots on the wings of Junonia spp.

Our local species in the Junonia genus, collectively called the Pansys, offer an almost similar range of ocelli-adorned species as the European Peacock. The Blue, Peacock, Chocolate and Grey Pansy species all have an interesting array of ocelli on their wings that probably function in the same way as their European cousins where the "eyes" are used to intimidate or deter predators.

Adapted ocelli on the tornal edge of the hindwings of Lycaenidae

The Lycaenidae have evolved their utilisation of ocelli into what is referred to as auto-mimicry to fool predators into attacking a less important part of their wings. The eyespots are adapted to look like the head of an organism, usually complete with "antennae" and the movement of the butterfly's hindwings, to direct a predator to attack a less critical part of the butterfly.

It is always interesting to observe how these Lycaenidae utilise colours, patterns and eyespots as a group of features to form a decoy to escape predatory attacks. Some of these eyespots come complete with silvery "eyebrows", orange and black eyespots and iridescent scales to emphasise an eyespot to attract a predator to "look at the wrong end" of the butterfly if it intends to attack.

Text and Photos by Khew SK

References :

01 December 2019

Butterflies of South Africa

Feature Book :
Butterflies of South Africa

A friend who recently visited South Africa managed to get me a copy of the Field Guide to Butterflies of South Africa by Steve Woodhall. A prolific author of several books on butterflies, Steve has effectively introduced the amazing diversity of South African butterflies through his excellent books and on social media to those of us in "faraway" lands who can only drool at the beauty of the butterflies in Steve's backyard.

The Field Guide to the Butterflies of South Africa was first published in May 2005. It was back then, the definitive book for butterfly enthusiasts and sold over 20,000 copies around the world! Steve went on to published several other books on butterflies in 2008, 2013 and 2016 and even has an app for iphones. He is currently working on the 2nd edition of his Field Guide and it is expected to be launched some time in 2020.

A nice "index" at the start of the book that shows all the families/sub-families of the butterflies featured in the species accounts section.

Butterflies of South Africa is a 440-page softcover book in a handy standard A5 sized format. The majority of the 1,800 photos in the book are by Steve and the remaining photos are by a group of his associates. The photos are mainly of field shots of the 660 species in South Africa, with some pinned specimen shots where field shots are not available.

Biogeography, vegetation ecosystems and habitats where the butterflies are found in South Africa

The book starts with the necessary introduction to butterflies - their taxonomic classification, biology, life history. anatomy, life history and so on. As the land area of South Africa is relatively large, the author elaborated on the different biomes (vegetation ecosystems) found in South Africa.

Introduction section with anatomy, taxonomy, etc.  Here, the Comstock system of wing venation is used

The largest section in the book, as can be expected, is the species accounts. The author organised the book by families, starting with the group with the largest number of sub-families - the Nymphalidae. It is then followed by Lycaenidae, Pieridae, Papilionidae and Hesperiidae. It is interesting to note that the 6th family in the butterfly world, Riodinidae (Metalmarks) is missing from South Africa.

This blogpost features some of sample pages of the species accounts. Each pair of pages are organised such that the write-ups are on the left, and the photos of species described are on the right. This is a convenient format for readers, as the pictures correlate directly to the write-ups without having to flip and cross-reference to a set of plates located elsewhere in the book, or even having to turn to a next page to view a photo of a butterfly that was described in a preceding page.

The descriptions of the species and other useful information are formatted on the left page, with the corresponding photos of the species on the right.  Photos are labeled for easy reference and there is no need to flip pages to refer to photos in appendices or plates in other parts of the book.

Each photo is labeled 1A, 1B, 2A and so on, to correlate to the write ups, showing upperside, underside, male or female of a species as the case may be. Where field shots are unavailable, these are supplemented with photos of pinned specimens. As field butterfly photography goes, it is not always possible that one can get good photos of all the uppersides and undersides of every species. Hence the most practical way of allowing readers to have a view of the uppersides (or undersides) of some species, a shot of a pinned specimen may be the best compromise.

Danainae section featuring the genus Amauris

The Danainaes of South Africa look quite different from those of Southeast Asia and have interesting common names to boot. The genus Amauris have common names like Layman, Friar, Novice and Chief! It appears that there are only 6 Danainae species in South Africa, of which the African Monarch (Plain Tiger in Singapore) is one species that we have in common. However, in South Africa, there are no fewer than 7 different forms of this species.

There are 21 Acraea species in South Africa compared to Singapore's single non-native species

The subfamily Heliconiinae is of interest, particularly from the genus Acraea. In Singapore, the Tawny Coster (Acraea terpsicore) was added as a new species in 2006. It is the sole representative of the genus found here. However, in South Africa, there are 21 Acraea species! The diversity in colours and patterns of this genus is quite amazing. But the similarities with A. terpsicore in wing shapes and general appearance are obvious.

The amazing Emperors (Charaxes) species of South Africa

The subfamily Charaxinae features some of the most spectacular butterflies in the world.  Their intricate patterns and colours are often a sight to behold.  Often referred to as the Rajahs in Asia, the genus Charaxes usually features robust-bodied species with twin tails.  Over in South Africa, there are 23 species (of which two species have single tails).  Definitely a country to keep Charaxes enthusiasts busy!

The Pansy species.  Blue Pansy is the name given to Junonia oenone in South Africa

South Africa shares many species of Junonia with Southeast Asia. There are 6 species, of which J. orithya (Blue Pansy in Singapore) is also extant as a different subspecies. However, in South Africa, it is called the Eyed Pansy instead, whilst the common name Blue Pansy is reserved for another species, Junonia oenone oenone.

The Bar species (related to the Silverlines in Asia)

The Lycaenidae family features amongst the largest number of species worldwide. Over in South Africa, the genus Cigaritis is related to the Spindasis found in our part of the world. And indeed, the jury is out (or rather, still debating) on which should be the "right" genus name for these pretty Silverlines. They are called "Bars" in South Africa but are no less pretty than their Asian counterparts.

Amongst these amazing Lycaenidae is the Golden Flash (Chrysoritis phosphor) a sought-after rarity in afromontane forest. Read the humourous article by Paulo and Rob Candotti about how Steve managed to capture one of these beauties.

The family Pieridae features the same white and yellow species that we can find all around the world, and South Africa's diverse range of these usually fast-flying brightly coloured butterflies is no exception. Some of the genera that are similar to the Southeast Asian butterfly fauna are Appias, Leptosia, Eurema and Catopsilia.

The spectacular Swordtail species of South Africa with their long elegant tails

The Birdwings and Swallowtails are amongst the most spectacular butterflies in the world. South Africa has 14 species in only two genera - Papilio and Graphium. As a comparison, Singapore is home to 18 species of Papilionidae. However, the Swordtails of South Africa are gorgeous and also share the same mud-puddling habits of their Asian cousins.

Some colourful Skippers of South Africa

The final family, the skippers or Hesperiidae showcases some pretty amazingly coloured species in South Africa. Generally similar in appearance to their Asian cousins amongst the majority of the species, the Hesperiidae of South Africa features a good variety of brown, orange and spotted species.

Coming Soon! The 2nd Edition of Butterflies of South Africa by Steve Woodhall

With this short blogpost introducing Steve Woodhall's Butterflies of South Africa, I hope that I have whetted your appetite for South African butterflies. If you are thinking of getting a copy of the book, the advice is don't! The reason is that Steve has been working on a 2nd edition of this book and will certainly outdo himself in the forthcoming 2020 edition that will be out on the shelves in May next year (according to Amazon).

Text by Khew SK : Photos reproduced from Butterflies of South Africa, with the kind permission of Steve Woodhall.