28 October 2018

Butterfly Anatomy

Butterfly Anatomy : Part 1
Scientific Names For Different Parts of a Butterfly

Names for the different parts of the forewing of a butterfly

In the appreciation of butterflies, nature's winged jewels, it is also important to be able to appropriately refer to the correct names to the different physical parts of the butterfly. Just like any bird, animal or even an inanimate object, like a car, there are proper names given to each part so that anyone describing or referring to the different aspects or parts of it can be universally understood.

Names for the different parts of the hindwing of a butterfly

This is no different for a butterfly, which has proper terms to describe different parts of its wings or body. In this blog article, we will systematically learn about the different parts of a butterfly from basic terminology to the detailed biological terms used by scientists to describe a butterfly's physical attributes. This article is not meant to be comprehensive or exhaustive, as a complete glossary of the scientific terminology may be too daunting for a hobbyist trying to learn about the proper names given to the different parts of a butterfly.

In many references, both online and in hardcopy books, diagrams and graphics depicting the different parts of a butterfly are often too complicated. This may be due to packing in as much information as possible for efficiency, where a lot of information is crammed into a single picture. I will attempt to introduce the anatomical features of a butterfly and their respective proper names progressively from the commonly used terms to more detailed scientific terminology.

Firstly, when one takes a look at a butterfly, the basic information would be the body and wings of the insect. Fundamentally, the body is divided into three segments - the head, thorax and abdomen. Then we take a look at the wings. All butterflies have four wings - left forewing, right forewing, left hindwing and right hindwing.

At the next level, would be the different parts found on the head, thorax and abdomen. These are important parts of the butterfly and often described or elaborated in references as part of the diagnostic features in butterfly identification. For example, the colour of the shaft of the antenna just after the club is a diagnostic feature for some skippers, whilst the shape of the tip of the abdomen can help to separate between a male and female of a species of butterfly.

Hence on the head, the important parts that should be highlighted are the antennae, eyes, palpi and proboscis. The middle section of the body, the thorax, is best thought of as a muscular anchor to which the head, legs, segmented abdomen, and wings are attached. The abdomen contains the digestive system, breathing apparatus, a long tubular heart, and the sexual organs. The abdominal exoskeleton is multi-segmented. Each of the 10 segments is comprised of a ring of a hard material called chitin. The segments are linked by flexible tissues, allowing the abdomen to bend, a necessity for copulation and egg-laying.

Upperside and underside of the wings of the same butterfly

Moving to the next level of detail, would be the wings and the correct names for different parts of the wings. Firstly, when we refer to the upperside (or dorsal) and underside (or ventral) side of the wings, the photos above indicate the convention for this. And then, considering that a butterfly's wing is triangular-shaped, each margin and angle has a given name.

Names for the external margins of the forewing and hindwing of a butterfly

Hence a butterfly enthusiast should familiarise himself with the names of these parts of a butterfly's wings. This is because when taxonomists describe the features of a butterfly's wings e.g. "the forewing apex is rounded in the female...", one will know exactly where to look at, and which part of the wing the description is referring to.

The terms apex, termen, base, tornus, dorsum and costa should be the next taxonomic terms that an enthusiast should know and remember. These are the general terms applied to the external edges of a butterfly's wings and are quite key to describing the wings.

When the description refers to the forewing dorsum margin (straight or curved) of the Dwarf Crow, an observer will be able to focus straightaway on the correct part to see the differences described.

In subsequent parts of this Butterfly Anatomy series, we will go into the wing surfaces, veins and internal taxonomic names for different parts of a butterfly's wings, and other detailed names of other different parts of a butterfly that is often used as descriptors and diagnostic features to identify different species. A glossary of other commonly used taxonomic terms will also be discussed.

Text by Khew SK ; Photos by Bob Cheong, Khew SK and Loh MY

20 October 2018

Lancers of Singapore

Lancers of Singapore
Featuring the Lancer skippers

The rare Yellow Chequered Lancer (Plastingia pellonia) perches on a leaf

This weekend's blogpost focuses on a group of butterflies in the Hesperiidae family (Skippers) that are collectively given the common English name of "Lancer". As shared in earlier posts on this blog regarding the interesting backgrounds in which the early collectors coined common names for butterflies, we have to sometimes do a bit of "forensic" analysis of some of these names to try to understand how some of these names originated.

The Yellow Vein Lancer (Pyroneura latoia latoia) is often observed at the flowers of the Bandicoot Berry (Leea indica) in the forested nature reserves of Singapore

Doing an online search for the meaning of "Lancer" would turn up primary definitions like "A soldier of a cavalry regiment armed with lances" or "a soldier who belongs to the part of an army that used lances in the past." The keyword in this case focuses on the word "lance" which is usually a long-handled weapon that is in the form of a spear. So the obvious etymology of the word "lancer" centres on a military personnel brandishing a long weapon.

A Chequered Lancer (Plastingia naga) perches in the shaded understory of its favourite habitat

So why would a butterfly have anything to do with a "Lancer"? This is the part that is probably more difficult to establish, and we can only speculate without any guarantees of a definitive conclusion, as there are often multiple viewpoints from which an observer can come to his own inference regarding a name.

Skippers, the collective name given to butterflies of the Hesperiidae family, are usually stout-bodied, moth-like in appearance and fast flyers. The individual species that are referred to as "Lancers" vary across different genera. But like most species of the family, they are skittish and zip around with great speed. Perhaps the early collectors saw in these species, a military-like demeanour in their wing shape and flight reminding them of soldiers brandishing lethal-looking weapons? A bit challenging to try to imagine these beautiful gentle creatures in that light, but to each his own.

The Chequered Lancer (Plastingia naga)

The first species that we feature here is the Chequered Lancer (Plastingia naga). That the Chequered Lancer is referred to by only its species name suggests that the butterfly is consistent throughout its geographical range with almost no perceptible differences in its appearance across the different countries where it occurs.

The underside of the Chequered Lancer has an attractive pattern of black veins and white rectangular spots. The upperside is a medium brown with hyaline spots on the forewings and yellowish streaks on both wings. The abdomen is striped black-and-white whilst the antennaa has a whitish band just after the club.

A Chequered Lancer sunbathes in the late afternoon showing its uppersides

A Chequered Lancer perches on the upperside of a leaf of its caterpillar host plant, Fishtail Palm (Caryota mitis)

The Chequered Lancer prefers well-shaded forest habitats where it perches on the top surfaces of leaves. It flies off rapidly when disturbed but often not too far away from its preferred habitats. The caterpillar of this species has been successfully bred on the Fishtail Palm (Caryota mitis) in Singapore.

The Yellow Chequered Lancer (Plastingia pellonia)

The Yellow Chequered Lancer is closely related to the Chequered Lancer and belongs to the same genus. It can be found in the same heavily-shaded habitats as the Chequered Lancer, but is much rarer, and usually spotted deep in forested areas within the nature reserves of Singapore.

A Yellow Chequered Lancer extends its palpi making it appear strange

The Yellow Chequered Lancer has a similar pattern on the underside of its wings to the Chequered Lancer, but instead of white spots, the overall ground colour of the butterfly is black-and-yellow, instead of black-and-white. The wings above are quite similar to the Chequered Lancer, but the spots are generally larger and more prominent.

The butterfly is considered very rare and its life history has hitherto not been recorded yet. The caterpillar host plant is very likely one of the jungle palms or even rattan, and it is hoped that we can document its full life history one day in the near future.

The Yellow Vein Lancer (Pyroneura latoia latoia)

At a glance, the Yellow Vein Lancer can look quite similar to the Yellow Chequered Lancer. However, upon a closer look, the differences are obvious and the two species can be separated quite easily. The butterfly is another forest-dependent species that is usually found within Singapore's nature reserves. Where found, sometimes several individuals can be spotted in the same locality, especially when the butterflies are feeding on the flowers of the Bandicoot Berry (Leea indica).

A glimpse of the upperside of a Yellow Chequered Lancer as it sunbathes in the warm sunshine

The Yellow Vein Lancer is dark brown on the upperside and the forewing has a series of pale yellow hyaline spots and streaks. The hindwing has a series of hyaline discal spots overlaid by a yellow band. On the underside, the veins are prominently marked in yellow with large spots and streaks between the veins. The antennae are yellowish from the apiculus to just behind the club, and the abdomen is striped black-and-yellow.

The species is moderately common in the nature reserves, and the caterpillars have been successfully bred on the Nibong Palm (Oncosperma horridum) that can be found in forested areas within the Central Catchment Nature Reserves.

The Pugnacious Lancer (Pemara pugnans)

The Pugnacious Lancer is the sole representative of the genus in the Southeast Asian Region. It is very rare in Singapore, and found mainly in forested areas within the nature reserves. Where observed, it is usually perched on the upperside of leaves with its wings folded upright. It is skittish like most skippers and tends to "jump" when it is photographed with a flash.

The upperside of the Pugnacious Lancer, showing the unique arrangement of the forewing spots

The species is dark brown above with a series of pale yellowish hyaline spots on the forewing. The underside is orange-brown and generously overlaid with ochreous scaling on both wings. On the forewing, there is a pair of black sub-apical spots adjacent to a single yellowish hyaline spot. The antennae are blackish brown throughout.

A Pugnacious Lancer perched on the upperside of a leaf with its wings folded upright

The caterpillar host plant of the Pugnacious Lancer is still unknown and given its rarity, it is hoped that a chance encounter of an ovipositing female of the species can fill in the gap in our knowledge of the early stages of this butterfly.

Text by Khew SK : Photos by James Chia, Goh LC, Khew SK, Koh CH, Nelson Ong and Jonathan Soong

13 October 2018

Butterfly of the Month - October 2018

Butterfly of the Month - October 2018
The Yellow Glassy Tiger (Parantica aspasia aspasia)

A female Yellow Glassy Tiger feeding on Lantana camara flower

The year 2018 crawls along into its tenth month and October is almost halfway through. It has not been a good year, both at the personal and at the work fronts, and I cannot wait for 2018 to end and to look ahead with greater optimism in 2019. It has been a year of ups and downs (mostly downs) and probably one of the more forgettable years in my life.

The local economy has not been favourable to the industry that I am in, and competition is rife and many companies are facing headwinds and a rather pessimistic outlook in the months to come. Throw in several unfortunate events directly affecting the company's branding and being in the news for the wrong reasons, it has been a year of hard knocks and bruised performances.

Health issues in the family also remind us of our mortality and vulnerability as we age. Time robs us of our youthful exuberance and leaves us a shell of what we used to be. But that's life, isn't it? No one gets younger or healthier as they age. But it is a grim reminder of the fear of losing a loved one, or facing major lifestyle changes due to negative impacts of the body's state of health. No one can say that they are prepared for such setbacks in their lives, because no matter how theoretically prepared we are, in reality, we aren't.

The global outlook is not that rosy either, with the US-China trade wars escalating in a tit-for-tat game of economic battles in the form of trade tariffs resulting in higher costs for some businesses causing overall global uncertainty in the near term. If we take a look back at history, the events preceding the two world wars started with economic crises. So let's hope that history won't repeat itself.

Even Mother Nature seems to be throwing out more extreme weather throughout the year and I don't recall back-to-back severe typhoons whipping Asian countries in recent history, resulting in multiple fatalities where these natural disasters struck. Add a couple of erupting volcanoes, a few earthquakes and tsunamis and hurricanes over in the western continents, it has been a particularly turbulent year for our world in the form of natural disasters too.

A male Yellow Glassy Tiger feeds on the flowers of a roadside White Weed (Ageratum conyzoides)

This month, we feature a seasonal visitor to Singapore, the Yellow Glassy Tiger (Parantica aspasia aspasia). Although recorded in Singapore by the early authors, the Yellow Glassy Tiger is very rare, and has not been seen for many years. Individuals have been irregularly observed from time to time, and these are believed to be strays from southern Malaysia making the occasional visits from across the Straits of Johor.

The Yellow Glassy Tiger's wings are predominantly bluish-grey with narrow black longitudinal streaks across both wings. Each wing has a bright yellow basal patch, with the yellow more extensive on the hindwing. It is this yellow colouration that gives the species its common name and distinguishes it from its all-grey cousins like the more common Blue Glassy Tiger and Dark Glassy Tiger found in Singapore.

The species flies with its characteristic slow and unhurried flight, which is typical of the "Tiger" butterflies of the Danainae subfamily. As the caterpillars of many of the Danainae species feed on lactiferous and toxic host plants, the adult butterflies display aposematic colouration and patterns, and are distasteful to predators.

A male Yellow Glassy Tiger feeding on the flowers of the Golden Dewdrop (Duranta erecta)

A female Yellow Glassy Tiger feeding on the flowers of the Indian Heliotrope (Heliotropium indicum)

The male Yellow Glassy Tiger has narrower and slightly more pointed wings, whilst the female has more rounded wings. The males also possess a conspicuous sex brand at the sub-tornal area of the hindwing. Females may be slightly paler in colour.

A male Yellow Glassy Tiger puddling at a damp streambank

Male Yellow Glassy Tigers have sometimes been observed to puddle at damp sandbanks near forest streams. Both sexes are frequently found feeding at flowering plants and wildflowers along roadsides and jungle trails. Although the species is relatively common in Malaysia but thus far, it is infrequently seen in Singapore.

A female Yellow Glassy Tiger spotted at Gardens by the Bay (Bay East), Singapore in Feb 2014

Locations where the Yellow Glassy Tiger was previously spotted included Hort Park, Alexandra Hospital Butterfly Garden, Pulau Ubin and Gardens by the Bay. Hopefully, this common species in Malaysia may one day make its home permanently in Singapore once again in the near future.

Text by Khew SK : Photos by Sebastian Ho, Khew SK, Loke PF, Anthony Wong and Mark Wong

06 October 2018

Butterfly Watch - Seasonality Study

Butterfly Watch - Seasonality Study
Butterfly Phenology in Singapore

I recently attended a talk by NParks' staff Zhou Boyi (Conservation Division) and Joy Wong (National Biodiversity Centre Division) on an advanced programme for the Butterfly Watch volunteers - Phenology or the study of annual seasonal or cyclical timing that affect butterflies in Singapore. Thus far, NParks' Butterfly Watch surveys, which were spun off from the BioBlitz activities, have received enthusiastic interest from many active members of the public.

Boyi informed me that the talk on butterfly phenological surveys was the next step to document more advanced studies on butterflies and encouraging the public to see and learn more about their observations of butterflies in Singapore. It was also important to collect data and records of various species, their seasonality and correlation with various events (e.g. haze, exceptional rainfall, drought, etc) over the course of the entire year.

The talk was held at the renovated bungalow at Dairy Farm Nature Park. The old bungalow was dilapidated for many years and was believed to be the residence of the staff, chief veterinarian and General Manager of the Cold Storage company that ran the dairy farm back in those days. After renovations, the bungalow is now used by NParks as a research and education centre. The layout of the bungalow was somewhat different from its original living room flanked by bedrooms. Today, the space has been reconfigured as a large lecture room complete with airconditioning.

Joy opened the talk with the background and purpose of the next phase of surveys which are intended to analyse the seasonality of the observations. She shared the various factors that affect phenology such as climate, differences in habitats, temperature, vegetation and a host of other factors.

A graphical analysis of the data that was collected over the many ButterflyWatch surveys by numerous volunteers was presented. It was interesting to see the trends across the various sites and the species distribution and diversity at different sites. Coincidentally, the site that recorded the highest number of species over the surveys was Dairy Farm Nature Park, where the talk was held.

There have not been many studies done on butterfly phenology in Singapore. The purpose of collecting more data would be to study the seasonal variations in the abundance of butterflies and understanding the conditions which cause these variations. Regular monitoring will add to the body of knowledge about the vulnerabilities of butterfly species and populations and devise management strategies to sustain Singapore's butterfly diversity.

Boyi then took over the next series of slides to introduce the various butterfly families found in Singapore. Each family's characteristics were discussed and their morphological attributes and differences highlighted. Lots of colourful pictures were shown to illustrate the features that Boyi was emphasising in his talk.

Boyi ended his talk with some quizzes on identification of butterflies and also featured a number of the more cryptic species that look very similar to each other. He also discussed the anatomical features of the butterflies and the scientific terms that are used to refer to different parts of a butterfly's wings.

Joy then summed up the day's presentation with the details on how the volunteers are expected to record and submit their results to NParks to collate and analyse the datasets.

It would be interesting to learn about some of our seasonal species like the Chocolate Albatross (which makes its appearance during certain months of the year) or why the Common Birdwing can be abundant during certain periods of the year but disappear completely from its favourite locations, only to reappear in numbers again cyclically. Are these seasonal appearances caused by plants, temperature, humidity, predators, parasites/viruses, environmental changes and a host of other factors? This is what longer term butterfly phenology studies can hope to give possible answers to these mysteries.

Text and photos by Khew SK.

Special thanks to NParks for organising the talk and to Joy and Boyi for delivering an interesting lecture on phenology.