25 June 2008

The Life History of the Great Helen

Life History of the Great Helen (Papilio iswara iswara)



Butterfly Biodata:
Genus: Papilio Linnaeus, 1758
Species: iswara White, 1842
Subspecies: iswara White, 1842
Wingspan of Adult Butterfly: 140mm
Caterpillar Host Plants: Maclurodendron porteri (Rutaceae)



A male Great Helen visiting a flower.


A male Great Helen visiting a flower, giving a view of its upperside


Physical Description of Adult Butterfly:
Great Helen is a large butterfly with a wing span of up to 14cm. The forewing is black above and, on both surfaces, the hindwing has a large white discal patch of four spots in spaces 4 to 7. There is a spatulate tail at each hindwing at vein 4. On the hindwing underside, there are blue post-discal lunules distal to the white spots in 2, 3 and 4. The female has a large black ocellus ringed with red in each of spaces 1a and 2 on the hindwing upperside (see the top picture in this article).

Field Observations of Butterfly Behaviour:
Locally the occurrence of this species is restricted to the Central Catchment Nature Reserves where its host plant, Maclurodendron porteri (old name: Acronychia porteri), is rather common, especially along MacRitchie Nature Trail and Nee Soon Pipeline. The adults usually fly rapidly at tree-top height, except when they come down to feed at flowering bushes or to look for oviposition sites. Like many of the Papilio species, when an adult stops to feed at flowers, it flutters its forewings while its hindwings are kept relatively still. When resting at a perch, the forewings droop backwards to almost or completely conceal the white discal patch on the hindwings.

Early Stages:
The host plant, Maclurodendron porteri, is a tree with simple, opposite and ovate leaves which are 10-18cm long. The leaves have a pleasant aromatic smell when crushed or when broken at stalks. Cancer researchers have found this plant to contain various flavonols with cancer-fighting attributes.


Host plant : Maclurodendron porteri


A female Great Helen attempting to oviposit on a leaf of the host plant

The eggs of the Great Helen are laid singly on undersides of young leaves of the host plant. Typically only one egg or one caterpillar is found on a single plant. The egg is pale creamy yellow with a finely roughened surface. It is nearly spherical with a diameter of about 1.8mm.


A fresh egg of Great Helen, diameter: 1.8mm


A mature egg, giving a faint front view of the head of the caterillar.

The egg found in the field took about 4 days to mature. The young caterpillar eats its way out of the mature egg, and then proceeds to finish up the rest of the egg shell. The newly hatched has a rather spiky appearance, and an initial body length of about 4mm. It is greyish white dorsally and dark brown laterally,


Newly hatched 1st instar caterpillar, length: 4mm


1st instar caterpillar, length: 6mm

In the first 4 instars, the Great Helen caterpillars look like bird droppings as they rest on the leaves. The resemblance in the 3rd and 4th instars are stronger with the body also assuming a slimy appearance. As in the case of all Swallowtail butterflies, the Great Helen caterpillars in all instars possess a fleshy organ called osmeterium in the prothoracic segment. Usually hidden, the osmeterium can be everted to emit a foul-smelling secretion when the caterpillar is threatened

As the 1st instar caterpillar grows to a maximum length of about 8mm, the dorsal whitish patches changes to orangy brown. There is a faint whitish saddle on the mid-abdominal segments, and white markings on the posterior abdominal segments. After about 3 days in 1st instar, the caterpillar moults to the next instar.


1st instar caterpillar, day 3 in this stage, ready to moult; length: 8mm

The 2nd instar caterpillar has a similar appearance to the late 1st instar caterpillar except for the more distinctly white saddle mark and posterior abdominal segments.
This instar lasts 3 days with the body length reaching about 16mm before the next moult.


2nd instar caterpillar, length: 10.5mm

In the 3rd instar, again there is no drastic change in physical appearance except for more dark brown to black patches appearing on the mottled body, and the more distinct white saddle mark. This instar takes 3 days to complete with body length reaching 25mm.


3rd instar caterpillar, length: 25mm

The 4th instar caterpillar looks almost the same as in the 3rd instar but with a more slimy appearance. This instar lasts 4 days with body length reaching about 38mm.


4th instar caterpillar, length: 36mm

The next moult brings the caterpillar to its 5th and final instar. Now there is a drastic change in appearance. There are two eye spots on the third thoracic segment, a transverse band at abdominal segments 1 and 2 , and oblique bars at mid-abdominal segments. After the moult to 5th instar, the body ground color is initially mottled green, but this changes gradually to the characteristic smooth green color after 1 day.


5th instar caterpillar, first day after the moult, length: 39mm

Now the shield-like thorax is very prominent. The eye spots on the 3rd thoracic segment are connected by a transverse green dorsal band with sinuous markings. A similar band, but in orangy brown, occurs between abdominal segments 1 and 2, and features pale purplish gaps between the sinuous markings. The first oblique bars, one on each side, run from the base of abdominal segment 3 to the top of segment 4. The second oblique bars occur at the two sides of abdominal segment 5, wide at the base and tapering to the dorsum. Both sets of oblique bars are mainly greenish brown dotted with tiny pale purple spots.


5th instar caterpillar, late in this stage, length: 65mm

The 5th instar lasts for 8 days, and the body length reaches up to 65mm. Toward the end of this instar, the body gradually shortens in length. Eventually the caterpillar comes to rest on the lower surface of a stem and becomes a pre-pupatory larva.


A pre-pupatory larva of Great Helen

Pupation takes place a day later. The pupa suspends itself with a silk girdle from the stem. It is mottled in shades of brown, green and white. The pupa has cephalic horns and a dorsal thoracic hump, and is angled in side view. Length of pupae: 36-37mm.


Pupa of Great Helen; fresh on left and mature on right

After 13-15 days of development, the pupa turns black as the development within the pupal case comes to an end. The next day the adult butterfly emerges from the pupal case. The beautiful undersides of its wings are fully displayed as it dries its wings for the first few hours after eclosion.


A newly eclosed female Great Helen drying its wings near the empty pupal case


A newly eclosed male Great Helen

Acknowledgments:

I would like to express my gratitude to Samsuri Ahmad of NParks for generous assistance in the identification of the host plant.


References:

  • The Butterflies of The Malay Peninsula, A.S. Corbet and H.M. Pendlebury, 4th Edition, Malayan Nature Society.
  • The Butterflies of Hong Kong, M. Bascombe, G. Johnston, F. Bascombe, Princeton University Press 1999
  • Plants that Fight Cancer, S.E. Kintzios, M.G. Barberaki, CRC Press 2004
Text and Photos by Horace Tan

22 comments:

mike said...

Wow! Great coverage and article. I didn't realise I had a Great Helen caterpillar on my curry plant. Had to flick it away...sorry. It was very persistent though, I put it on another potted plant about 2 feet away and next day it was back on the curry plant. I'm in the Teck Whye HDB area. Are there other green caterpillars with this eye pattern that I could've been confused with?

Horace said...
This comment has been removed by the author.
Horace said...

Thanks, Mike for your kind words.

Based on the recorded host plants for various Papilio species, the caterpillar you described as persistently going back to the curry plant should be that of Common Mormon (Papilio polytes). Of course there is a possibility that it is one of the other Papilio species, as the caterpillars of Papilio do look alike, being bird-dropping like in the early instars, and green body with eye spots in the final instar. Differences in the final instar usually come in the form of having different colours in the markings, and some details in the markings.

samuel said...

great post on the great helen.. i've always wanted to see a living, breathing specimen of this butterfly but they unfortunately seem extremely hard to come by. someday perhaps..

Horace said...

Thanks Samuel.
The place which offers a best chance to see a Great Helen in the wild is MacRitchie Nature Trail, either on the board walk or on the trail proper. Best of luck.

mike said...

Thanks for your reply Horace, very interesting. Are there any pictures of the common mormon's instars on this blog or elsewhere? I wish I had taken a photo. I think I've also had the pupa of the banded swallowtail on my front door once. Monitored it and one day saw the butterfly flutter off.

Horace said...

The life history of Common Mormon has been recorded by a number of ButterflyCircle members, and the pictures were posted in the forum. You could find a detailed write up on the Internet at this Wikipedia page with URL: http://en.wikipedia.org/wiki/Papilio_polytes

Interesting note on that possible pupa of banded swallowtail. Did you manage to capture a shot of that butterfly which fluttered off?

mike said...

Hi Horace, no I didn't get a pic of it. I've read the wiki on polytes and the instars look somewhat similar and confusing. My kaffir lime plant has just been invaded by two caterpillars. Here are the pictures taken 1 day apart. It's amazing how fast they change. Could you help confirm which one of they are...

http://farm4.static.flickr.com/3079/2652618662_f3ee911f5f.jpg
http://farm4.static.flickr.com/3242/2651791203_97ca8eccd6.jpg

Horace said...

Mike,
An interesting looking Papilio caterpillar you have there. The oblique band at segments 3 and 4, and the one at segment 5 are not fully formed or connected. I cannot tell for sure the species ID at this stage as there could be further changes to these bands as the catepillar grow. Possible IDs are Common Mormon and Lime Butterfly IMHO.
Do keep an eye on the caterpillars and take note of the adults when the time comes.

mike said...
This comment has been removed by the author.
mike said...

Horace, agree that it looks more like the lime butterfly. Roughly how long would I have to wait to see the pupa and butterfly? My wife's getting a little frantic because it's devoured almost all the shoots of our small pot of kaffir lime. Do you think it is possible to cut a few leaves/twigs and place the 2 caterpillars in a box...will they pupate indoors? Am just worried that when they finally come out I won't get to see it before it flies off.

Horace said...

Mike,
The final instar of the Papilio consumes quite a bit of the lime leaves compared to the earlier instars. With two of them, you might want to consider getting another pot of the kaffir lime. My estimate is about 3 to 5 days for the final instar before it stops feeding.
It will be a good idea for you to house them in a plastic container with leaves/twigs as you suggested. Firstly you will be sure that they will pupate and eclose in it, so that you can ascertain their ID. Furthermore, you will eliminate the risk of bird and parasitoid attacks on the caterpillars.

mike said...

3 to 5 days!!?!! Can't wait! Half the plant is gone today when I checked and the two caterpillars plump as pumpkins. So is it ok to move them now?

Thanks for your quick replies...

Horace said...

Mike,
The earlier you move them, the lesser chance they are exposed to risks I mentioned before.

mike said...

Hi Horace, am back with some pictures.
http://farm4.static.flickr.com/3192/2674483628_9afb2077b1.jpg
http://farm4.static.flickr.com/3139/2673682243_0a5b328816.jpg

The first one is the 'older brother' and the second was still in the caterpillar stage when the former had already pupate. They are now both indoors and in the pupa stage. I almost lost older brother but finally found the pupa hanging on my curry plant, so I chopped the section and have put them both in a glass vase. Am quite keen to take up the challenge of photographing the eclosions...any idea what time I should keep awake? I read the eclosion photography article, hope I'll have enough patience.

Horace said...

Mike,
You patience and care pay off! Congrats for successfully having two pupae on hand.
Typically, but not always, the eclosion takes place in the early part of the morning. The day before, the pupa becomes darkened, and you soon get ready with your camera equipment for the eclosion overnight or in the next morning. It will be rather challenging but rewarding if you finally get to
witness the eclosion event.
You might want to get in touch with Bobby, the man behind the blog article on eclosion sequences, to get more tips and other relevant advice.

mike said...

Today, a rather worn out common mormon visited my garden and seemed to be trying to lay some eggs but after checking there were no signs of eggs. Then a lime butterfly came. So now I know who is in the neighbourhood but it is anybody's guess who the parent of my 2 pupae are. So I'll just have to wait a few more days. It's been a week since they pupated. Hope they eclose soon - before I go outstation and I will be forced to leave them outside. I'll try to get Bobby if I hv any questions. Keep u posted.

mike said...

Hi Horace, it's a Lime butterfly after all.
I missed the eclosion 'coz I was at work but my wife managed some shot of the butterfly still close to the pupa and after that I had a chance to take it out to the garden for some quick shots.

http://farm4.static.flickr.com/3239/2691809923_323a2b8bd8.jpg
http://farm4.static.flickr.com/3109/2691806455_7f75b632f0.jpg
http://farm4.static.flickr.com/3228/2691806381_19076e2a79.jpg
http://farm4.static.flickr.com/3064/2692619966_a333868ed6.jpg

Horace said...

Mike,
Thanks for the update on the eclosion of the lime butterfly. Both you and your wife did very well in taking great shots of the newly eclosed adult. Congrats for a life history well recorded.

afiqa said...

Hi horace.

Great blog you have here. :)Anyway, I have a pupa of a lime butterfly and as i was observing it, it started to shake quite vigorously. Do you think there's anything wrong with it? Thanks.

Horace said...

Hi Afiga,
Sometimes a pupa might react with a shake or two to external stimulii like sudden loud noise, shining of strong light or even tiny insects crawling on its body.
Keep observing. Hopefully you get the chance to witness the miraculous event of eclosion.

afiqa said...

Ohh i see... Thanks for sharing. :)