Mergers, Partnerships & Betrayals

Mergers, Partnerships and Betrayals
The Miletinae - The Harvesters


A multi-tasking pair of Bigg's Brownie (Miletus biggsii biggsii) - mating & feeding amongst their protector ants

In the real corporate world, the title of this blog would probably not elicit much interest and excitement, other than offering a good read about yet another unfortunate company being swallowed up, or employees being thrust into a chasm of anxiety about their future.

A Bigg's Brownie (Miletus biggsii biggsii) feeding off what appears to be a "herd" of mealy bugs that are tended by their protector ants

In the world of Lepidoptera, however, the partnership between butterfly and ants is already a well-studied topic by entomologists. Myrmecophily, or the positive interspecies association between ants and butterflies (or rather, their caterpillars) has been widely studied. This symbiotic association occurs with some Lycaenidae caterpillars evolving specialised organs that exude honeydew in return for protection by the ants. These caterpillars then go about their daily business of feeding on the leaves of their host plants, whilst enjoying 'armed' guards' protection from predators.

However, there exists a subfamily within the Lycaenidae family - the Miletinae, that is unique in the sense that their caterpillars are predatory or "carnivorous" in the butterfly world. Whilst it is generally well-known that most caterpillars are "herbivorous" and generally feed on leaves, buds and flowers of plants, the Miletinae (or commonly referred to as the Harvesters) species' caterpillars feed on a variety of Homoptera like aphids, coccids, mealy bugs and one species even feeds on ants' larvae!

In Singapore, the Miletinae is represented by five genera - Allotinus, Logania, Spalgis, Miletus and Liphyra. Other than Liphyra, the other genera have caterpillars that feed mainly on a variety of Homoptera.

The aphids, coccids and mealy bugs, which form the principal diet of the caterpillars of the four genera mentioned, tend to feed on young shoots of various plants. These insects have adapted piercing mouth parts that pierce and suck the sap of plants - usually soft-stemmed ones. The Homoptera must suck large amounts of sap from the plant to get their nutrients. Much of the sap is a sugary fluid that cannot be digested. This extra liquid is passed through their body and excreted as "honeydew." Ants and other insects "farm" the Homoptera and collect honeydew for their own food. In return for their food, ants will protect the Homoptera that provide their colony with a food source.

In the field, observations have been made of the Miletinae adults feeding off the secretions of the aphids, mealy bugs and coccids. The butterflies do this brazenly, without any fear of being attacked, in the presence of the protective ants that are also 'milking' the aphids or mealy bugs of their honeydew.

Walking gingerly in a minefield of ants!

Besides feeding off the honeydew, the Miletinae also lay their eggs where the aphids and mealy bugs are present, and the caterpillars of these species feed on the aphids and mealy bug community.

A Pale Mottle (Logania marmorata damis) amidst mealy bugs and their "farmers"

It is interesting to note that the ants neither extract honeydew from, nor tend to the caterpillars in this case. They go about their business of tending to the aphids or mealy bugs, but leave the caterpillars alone - despite the caterpillars devouring their "herd"! Why then, don't the normally ferocious ants attack and kill the predatory caterpillars?

Miletinae caterpillars amongst their "sheep" which provides food as they grow

Researchers have postulated that the caterpillars (and even adult butterflies) have some kind of chemo-mimicry that render themselves 'invisible' to the ants. In other words, as far as the ants are concerned, the Miletinae adults and caterpillars are perceived as just another ant in the colony.

Hello? Are you my brother? An ant checks out a Lesser Darkie (Allotinus unicolor unicolor).

Therefore, although the caterpillars and adult butterflies of the Miletinae derive 'protection' from the ants, they give nothing back in return. On top of that, the adult butterflies partake of the honeydew that are secreted by the aphids and mealy bugs, and their caterpillars feed on the ants' source of food. Hence the "betrayal" part of the whole situation, where the ants have been hoodwinked into a win-lose relationship with the Miletinae.

A Lesser Darkie feeds on honeydew produced by some aphids that are tended by their farmer ants

An even more extreme situation occurs with the Moth Butterfly (Liphyra brassolis abbreviata). The caterpillar of this species feeds on the larvae of the Weaver Ant (Oecophylla smaragdina). It is interesting to note that the caterpillar feeds and grows inside the nest of the ants, and has evolved a clever way to escape the wrath of the ants when it ecloses. Our earlier blog article describes the Moth Butterfly.

A newly-eclosed Moth Butterfly (Liphyra brassolis abbreviata) whose caterpillar feeds on ant grub

This unique characteristic of the sub-family Miletinae in the butterfly world is amazing, and runs contrary to the conventional belief that all caterpillars are herbivorous and feed only on plant material. The adult butterflies of the five genera of the Miletinae found in Singapore are therefore very widespread, having little dependence on the location of host plants, as their "host" food is actually other living insects! Hence wherever there is a colony of aphids, coccids or mealy bugs, the adult butterflies of this sub-family will seek them out, for food for themselves as well as their young.

An Apefly (Spalgis epius epius) one of the Miletenae whose caterpillars also feed on Homoptera

So do look out for these butterflies and special behaviour when you are out in the field!

Text by Khew SK ; Photos by Sunny Chir, James Foong, Federick Ho, Khew SK, Loke PF, Bobby Mun, Horace Tan & Tan Tze Siong

Life History of the Mottled Emigrant

Life History of the Mottled Emigrant (Catopsilia pyranthe pyranthe)

Butterfly Biodata:
Genus: Catopsilia Hübner, 1819
Species: pyranthe Linnaeus, 1, 1758
Subspecies: pyranthe Linnaeus, 1, 1758
Wingspan of Adult Butterfly: 65mm
Caterpillar Local Host Plants: Senna alata (Leguminosae, common name: Seven Golden Candlesticks)


A Mottled Emigrant perching on a grass blade.


Another Mottled Emigrant sighted on its perch in an urban park where its host plant is found.

Physical Description of Adult Butterfly:
Above, the wings are greenish white and the forewing has a black apical border and a black cell-end spot. This black border and the cell-end spot are respectively broader and larger in the female than in the male. Beneath, the wings are of a darker and greenish-ochreous hue and there are many rather faint and short transverse striae in reddish brown, giving it a "mottled" appearance.

A newly eclosed female Mottled Emigrant resting near its pupal case.


Another newly eclosed Mottled Emigrant.

Field Observations of Butterfly Behaviour: The Mottled Emigrant is described in C&P4 as being the commonest and most widespread species of Catopsilia in Malaya. However, the reverse is true in Singapore as it is the rarest of the three Catopsilia species locally. The fast flying adults are typically found at the fringes of nature reserves or in a few wastelands where its host plant, Senna alata, is growing. In addition, where this plant is cultivated, it is likely that Mottled Emigrant will make its appearance as well.

Early Stages:
The host plant, Senna alata, is a shrub up to 3m high with flowers growing in columns resembling fat candlesticks. The leaves are simple pinnate with large leaflets, each of which is 50-80mm long. The caterpillars of the Mottled Emigrant feed on the relatively young to middle-aged leaflets.

Host plant: Senna alata (Seven Golden Candlesticks).


A mating pair of the Mottled Emigrant.

The eggs of the Mottled Emigrant are laid singly on the upperside of a leaflet of the host plant. At times, more than one egg can be found on the same leaflet. The long spindle shaped egg is laid standing at one end with a length of about 1.7-1.8mm. It is white in color with vertical ridges and numerous indistinct and intermittent horizontal ridge lines. The micropylar sits at the tip of the standing egg.

Left: fresh egg. Right: mature egg showing the head at the hole near the top.

The egg takes about 2 days to hatch. The newly hatched has a length of about 2.7mm and has a pale white to yellow head capsule. It has a cylindrical and pale yellowish green body featuring dorsal, dorso-lateral and lateral rows of small tubercles running lengthwise. Each tubercle has a short seta emerging from the middle of it.


Two views of a 1st instar caterpillar, early in this stgae, length: 2.8mm.

After hatching, the young caterpillar eats the empty egg shell for its first meal, and then moves on to eat the leaf lamina. The growth is fast paced and the body length reaches about 4.5mm in this 1st instar which lasts just 1.0-1.5 days.

Two views of a late 1st Instar caterpillar hours before its moult, length: 4mm.

The 2nd instar caterpillar is yellowish green in color on both body segments and the head. The body is covered in rings (about six for each body segment) of numerous small black tubercles from which very short setae emerge. The head capsule also features numerous similar tubercles. This instar lasts about 1-1.5 days with the body length reaching 8-9mm.


Two view of a 2nd instar caterpillar, length: 4.1mm

The 3rd instar caterpillar resembles the 2nd instar caterpillar closely except for the appearance of a faint whitish lateral lines. Towards the end of this instar, a faint yellow line also appears on the upper edge of this white line. This instar takes about 2-2.5 days to complete with body length reaching about 12-14mm.


3rd instar caterpillars. Top: 9mm. Bottom: 12mm.

The white-yellow stacked lateral line on the 4th instar caterpillar is much more prominent. Furthermore, the first or first 2 rows of dark tubercles above this lateral line are larger with a bluish shine, thus forming prominent outline to the white-yellow line. This penultimate instar lasts 2-2.5 days with body length reaching about 23-25mm.


Two views of a 4th instar caterpillar, early in this stage, length: 14mm.


Two views of a 4th instar caterpillar, late in thie stage, length: 24mm


A close-up view of the stacked white-yellow line and row/rows of larger black tubercles above.

The 5th and final instar caterpillar resembles the 4th instar caterpillar closely with no obvious changes. The 5th instar lasts for 2.5-3 days, and the body length reaches up to 41-45mm.


Two views of a 5th instar caterpillar, newly moulted, length: 26mm.

5th instar caterpillars. Top: 39mm. Bottom: 45mm.

On the last day of the 5th instar, the body of the caterpillar shortens and changes to a dull shade of pale green. It ceases feeding and comes to rest on the midrib on the underside of a leaflet or the stem/stalk on the host plant. Here the caterpillar spins a silk pad and a silk girdle to secure itself and then becomes immobile in its pre-pupatory pose.

A pre-pupatory larva of the Mottled Emigrant on the leaf underside.


Pupation takes place about 0.5 day later. The pupa secures itself with the same silk girdle as in the pre-pupal stage, but with cremaster replacing claspers in attaching the posterior end to the silk pad on the stem. The pupa has a pointed head, and its yellowish green body has a yellow lateral line on each side. There is a dorsal protrusion with a yellow ridge line on the thorax. The keel formed by the tapering wing case is much less pronounced than those seen in the Eurema spp.

Length of pupae: 28-29mm.

The pupation event of a Mottled Emigrant caterpillar.

Two views of the pupa of a Mottled Emigrant.

Two views of the mature pupa of a female Mottled Emigrant.
The now transparent wing pad shows the broad black border and cell spot.

After about 5 days of development, the pupal skin turns translucent as the development within the pupal case comes to an end. The yellow coloration and black borders on the forewing upperside are now discernible. The following day, the adult butterfly emerges from the pupal case.

The eclosion sequence of a male Mottled Emigrant.

A newly eclosed Mottled Emigrant drying its wings on its pupal case.

References:

• The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, Malayan Nature Society. [C&P4]
• Butterflies of Thailand, Pisuth Ek-Amnuay, 1st Edition, 2006

Text by Horace Tan, Photos by Jason Ng, Benedict Tay, Bobby Mun, Anthony Wong and Horace Tan

Return to Semakau

Return to Semakau
A Hot Sunday Butterfly Outing

Last Sunday, 7 Mar 2010, twelve members of ButterflyCircle made a return trip to Pulau Semakau for a butterfly survey, after the last outing over a year ago on 28 Feb 2009. The objective of this outing was to ascertain if there are more species that have been missed out in the previous surveys during the writing of the book on Semakau.

This time, the team comprised several senior members of ButterflyCircle, as well as a number of newbies going to Semakau for the first time.

The happy adventurers!

After an uneventful and short trip under an overcast morning sky, the group disembarked at the jetty on Semakau, and greeted by our bubbly host, Patrick Yu of the NEA. For the benefit of the first-timers, we did a quick tour of the waste processing facilities at the main building, before heading towards the forested patch where we did our surveys during our last few outings.

Sunny showing Federick the naval map and the islands around Singapore

By this time, the sun was out and the scorching heat of the past few days greeted us. Whilst some of us headed for the shade of the forested area, the braver members headed out to the grassland of the filled cells. Surprisingly, we did not encounter the 'commando' mosquitoes of the previous trips, and we attributed this to the hot and dry weather where all the stagnant pools of water and streams were all but parched.

ButterflyCircle members, the hunt begins!

But our butterfly friends were still up and about, and the usual Common Tigers, Tawny Costers and Grass Yellows were fluttering restlessly about the wild grasses. The shady forested areas were still active with butterflies, with the Orange Tit (Hypolycaena thecloides thecloides) flitting skittishly around the shrubs, whilst there were a few Palm Bobs still lurking around near their favourite perches.

Two Danainae - the King Crow (Euploea phaenareta castelnaui) and the Spotted Black Crow (Euploea crameri bremeri) were added to the Semakau checklist for the first time. Both were spotted in the forested patch. The Common Awls (Hasora badra badra) were found in the shady areas and behaved typically by zipping under leaves and hanging upside down. A large butterfly which appeared to resemble a Palm King (Amathusia phidippus phidippus) zoomed across my path but being unable to have a shot for positive identification, I am leaving it out of the checklist for the time being.

A mating pair of the Two Spotted Line Blue

Out in the open grasslands, the Two Spotted Line Blue (Nacaduba biocellata) was still at its favourite location under the host plant's shade. Blue Pansys and some skittish skippers abound in the long grass areas. This time around, four new Lycaenidaes were spotted. These were Pea Blue (Lampides boeticus), Gram Blue (Euchrysops cnejus cnejus), Indian Cupid (Everes lacturnus rileyi) and the Pygmy Grass Blue (Zizula hylax pygmaea) and were added to the checklist.

The hot humid weather started to take its toll on most of our members, and we retreated to the 'base camp' hut for shelter and lunch. After a rest, some of us made a second tour in the forested patch and some headed for the grassy area in the hope of spotting further new finds. However, our tally of new species spotted stopped at six.

John Lee, our fearless bee and wasp expert, was also having a field day chasing after his busy subjects.

At around 2 pm, most of us were drained by the heat, and we decided to call it a day. Happy with an additional six species to the Semakau Checklist, we called for our transport and Patrick Yu happily obliged. We were treated to a short rest at the airconditioned administration building whilst our boatman headed out from West Coast Terminal.

We bade farewall to Patrick and his NEA colleagues and boarded the boat "3931" back to the main island of Singapore. The trip back was uneventful, and some of us took the chance for a much-needed nap on the boat. Before long, we had our feet planted firmly on land again, and headed for our transport back home.

The ButterflyCircle Dozen
Back Row : L-R : Sunny, John, Horace, Ben Jin, Khew & Nelson
Front Row : L-R : Ellen, Cher Hern, Loke, Chng, Anthony & Federick

Thus ended a rather fruitful re-visit to Semakau after over a year when we last did our survey on the Landfill Island off the southern coast of Singapore island. Thanks to all ButterflyCircle members who contributed and participated in this first survey of 2010.

Updated Checklist of Butterflies Observed at Pulau Semakau (As at 7 Mar 2010)

1. Common Mormon (Papilio polytes romulus)
2. Common Grass Yellow (Eurema hecabe contubernalis)
3. Three Spot Grass Yellow (Eurema blanda snelleni)
4. Striped Albatross (Appias libythea olferna)
5. Common Tiger (Danaus genutia genutia)
6. Black Veined Tiger (Danaus melanippus hegesippus)
7. Blue Glassy Tiger (Ideopsis vulgaris macrina)
8. King Crow (Euploea phaenareta castelnaui) - NEW
9. Spotted Black Crow (Euploea crameri bremeri) - NEW
10. Striped Blue Crow (Euploea mulciber mulciber)
11. Tawny Coster (Acraea violae)
12. Baron (Euthalia aconthea gurda)
13. Leopard (Phalanta phalantha phalantha)
14. Perak Lascar (Pantoporia paraka paraka)
15. Autumn Leaf (Doleschallia bisaltide bisaltide)
16. Great Eggfly (Hypolimnas bolina bolina)
17. Blue Pansy (Junonia orithya wallacei)
18. Blue Nawab (Polyura schreiber tisamenus)
19. Common Palmfly (Elymnias hypermestra agina)
20. Silver Forget-Me-Not (Catochrysops panormus exiguus)
21. Gram Blue (Euchrysops cnejus cnejus) - NEW
22. Pea Blue (Lampides boeticus) - NEW
23. Indian Cupid (Everes lacturnus rileyi) - NEW
24. Ciliate Blue (Anthene emolus goberus)
25. Centaur Oakblue (Arhopala centaurus nakula)
26. Common Tit (Hypolycaena erylus teatus)
27. (Hypolycaena thecloides thecloides)
28. Long Banded Silverline (Spindasis lohita senama)
29. Two Spotted Line Blue (Nacaduba biocellata)
30. Tailless Line Blue (Prosotas dubiosa lumpura)
31. Lesser Grass Blue (Zizina otis lampa)
32. Pygmy Grass Blue (Zizula hylax pygmaea) - NEW
33. Common Awl (Hasora badra badra)
34. Common Palm Dart (Telicota colon stinga)
35. Yellow Palm Dart (Cephrenes trichopepla)
36. Palm Bob (Suastus gremius gremius)
37. Chestnut Bob (Iambrix salsala salsala)
38. Lesser Dart (Potanthus omaha omaha)
39. Large Dart(Potanthus serina)
40. Banded Demon (Notocrypta paralysos varians)

Text by Khew SK : Photos by Sunny Chir, Chng CK, Federick Ho, Khew SK, Koh Cher Hern, Loke PF, Nelson Ong, Tan BJ, Ellen Tan & Horace Tan