Tuesday, 6 February 2007

#6 A Pupating Caterpillar

The metamorphosing of a caterpillar into a butterfly is amazing! I had the opportunity to observe this spectacle in my backyard so I photographed the sequence.

Dainty Swallowtail, Papilio anactus.

As I am in the habit of wandering around my yard early most mornings and evenings, I am aware of some of the hidden happenings and subtle changes in my garden. No doubt there are a multitude of lives and deaths overlooked literally under my feet and in front of my nose, but my keen eye for detail often unearths wonderful surprises. The caterpillar of the Dainty Swallowtail Butterfly was one such beauty.

Dainty (or Dingy) Swallowtails, Papilio anactus, belong to the Papilionidae family and lay their eggs on cultivated citrus and a few native species including wild lime and orange, and are common over eastern mainland Australia and southern South Australia. My young orange tree was struggling to survive, so when I found grubs on it I was tempted to dispatch them.

But how could I dispose of such an impressive caterpillar.....

At first sight a caterpillar might appear to have countless legs. But a caterpillar is an insect and therefore has only six true legs. Notice in the image above the three pairs of black legs under the thorax behind the head on the right-hand side of the caterpillar - these are the true legs. The orange suction-looking buds under the abdomen are not legs, and nor are they suckers, but clusters of minute hooks which assist with walking.

Defense strategies

And have you ever noticed countless caterpillars on a shrub but yet the bush next to it appears grub-free, and wondered why they choose to eat one plant species rather than several? Throughout evolution, some butterfly species have developed mechanisms to isolate and concentrate noxious chemicals in their caterpillar bodies. Some female butterflies searching for host plants upon which to lay their eggs, are attracted to plants which provide specific noxious chemicals to their caterpillars.

The Dainty Swallowtail caterpillar feeds on citrus, and secrets a nasty-smelling fluid from glands behind the head when it is threatened or disturbed. This secretion smells like decaying citrus.

Butterflies also advertise their distastefulness to preditors with brightly coloured wings. Butterflies fly by day, so need a deterrent to would-be preditors, whereas moths mostly fly by night and are more dully coloured. The chrysalis that houses the pupating butterfly is motionless and therefore relies on camouflage as its only defense.

The top caterpillar begins its final moult, while the lower two are now pupae.

The caterpillar will shed its skin 4 or 5 times in order to grow. Before the final moult, the caterpillar attaches itself to the host plant with silk and then sheds its skin to reveal a different skin which hardens into a pupa, or chrysalis.

The pupa attached to the orange tree blends into its surroundings, while the other caterpillar pictured did not survive the pupating process.

Caterpillars focus their energy on eating and growing. They have strong mandibles for chewing, and most are nocturnal feeders remaining motionless on the host plant throughout the day. They can not mate or reproduce.


Butterflies focus their energy on spreading out and reproducing. Most butterflies only live for about 2 weeks, so they do not have time to waste.

Butterflies do not have teeth or mandibles, but have a coiled proboscis which, when unrolled, acts similar to a drinking straw for probing flowers and sucking up nectar. Their brightly coloured wings will aid in finding and attracting butterflies of the same species.

When a mate is located and accepted, they will face opposite directions and mate end-to-end with abdomens joined. The female will then search an appropriate host plant on which to lay her eggs.

The beautiful Dainty Swallowtail Butterfly (Papilio anactus) newly emerged.

As my gardens become established and my shrubs and trees mature, I hope to provide habitat for many butterfly larvae. If you are lucky enough to see a chrysalis hanging in your garden, you too can feel satisfied that you have provided habitat for the continuing life cycle of a butterfly. Here is a good site (although not Australian) for children to check out butterflies and their life cycle.

The life cycle of a butterfly is a remarkable and complex process. I hope my brief and simple explanation might inspire tolerance for garden grubs. Most will not do irreparable damage to your plants.


Esperance Blog said...

Hi Gaye, not only a stunning butterfly, but a stunning caterpillar too. Unfortunately we do not get these spectacular butterflies and I am often green with envy when I view some of the NSW invertebrates. Another great blog.


Anonymous said...

hello there Gaye,

Nice pics once again. Any chance of posting details of how you took your shots? I've finally decided on what camera to get (Canon A630) and order it tomorrow. I'll need some one to get tips from!

I've also been messing with my blogs and there's nothing to see there at present, but I'm hoping to have something worth looking in a week or so.

Off now, I'll catch up with you in Scribbly.


Gaye from the Hunter said...

Thanks Jack, although we do get some beaut butterflies here, north Queensland is the place for spectacular butterflies. But I certainly appreciate our local invertebrates.

I haven't got a flower garden, so when my native shrubs and herbs are not flowering there is a lack of nectar for insects. Perhaps I should sprinkle a packet of mixed flower seeds in one end of the vege garden.


Gaye from the Hunter said...

Thanks Peter, I used my point-and-shoot camera (Olympus C70 3.2 megapixel) for these images and just pointed, composed and shot. A flash would have brightened the caterpillar's colours, but I didn't think of it at the time.

Congratulations on your purchase. You will no doubt find that digital photography will take your nature observations that one step further. Being able to study your images after the subject has flown or scampered off allows you to view the detail at leisure and to further your research. You'll be able to get to know your nature subjects much better and then look forward to seeing the same subjects in their natural environment again with a little more knowledge up your sleeve.

Have fun.


Evan said...

That's a very cool butterfly. I have yet to see this species. Looks a lot like the Cairns Birdwing, which I got to see at the butterfly house at Coffs Harbour.

The butterfly that has been intriguing me of late is a bright blue one. It is a gorgeous thing.

I like the praying mantids best out of our invertebrates.

Thanks for the great post.


Gaye from the Hunter said...

hi Evan, thanks. If you ever venture to far north Queensland, the Butterfly House at Kuranda is a must see for butterfly enthusiasts.

The mantids are certainly interesting creatures (not very co-operative photographic subjects though). I saw a hatch last week and I couldn't believe that so many hatchlings could fit in that small cocoon.

I'm pleased you enjoyed my butterfly observaions.


Geoff_D said...

I had hoped to get shots of the Common Crow Butterflies emerging from their wonderfully shiny chrysalis, but the ants somehow got in and devoured them before the metamorphosis was complete.

Gaye from the Hunter said...

hi Geoff, that's a shame, when there seems to be plenty of ants and few butterflies, but I guess that's just nature.

What sort of plant was the shiny chrysalis on? I'd like to grow some plants to attract different species of butterflies to my garden.


Gaye from the Hunter said...

geoff, I've just looked up the Crow Butterfly and its other common name is Oleander Butterfly. I certainly won't be growing oleander, but there is a feral one up the road that I might check out.


elfram said...

Lovely photos, and a well-written commentary, with personal involvement diplayed nicely.

Gaye from the Hunter said...

Thanks elfram, I do get involved in things and have to be careful not to ramble to much throughout my nature blog.

I'm considering starting a personal blog so that I can ramble a bit. I have a lot to share, some of which just might be of interest to others. But I will have to do so with care if I link it to my nature blog, as I am striving to maintain a "student-friendly" site. We will see.....

Anonymous said...

I found one of these colourful caterpillars on my orange tree. I put it in a jar with some leaves and twigs and gave it to my wife who is a reception teacher. The children were able to experience the metamorphosis and today they released the beautiful butterfly. What a precious experience.

Gaye from the Hunter said...

I am always thrilled to hear about children interacting in a positive manner with nature, especially helped along by adults who can offer explanations and simple information that the children can retain.

A lovely story indeed, and thank you for relating it here.


Junior Lepid said...

Lovely series, Gaye.

I hope I will be as lucky as you but unfortunately, because of an apparent decrease in butterfly populations in my area, I doubt I will.

Gaye from the Hunter said...

Thanks Junior Lepid,

unfortunately, my twig of an orange tree gave up its battle for life, so now I don't have any citrus trees for this species.


Kate said...

I found a whole heap of these caterpillers on my lime tree the other day and as my tree has never produced an eatable lime I figured I'd let the little fellas eat there fill instead of spraying. When a couple cocooned I got very interested. After I read this blog I went straight out and cut a whole heap of branches of a popped them in tanks. I am a child care worker and they will be coming to work with me so the children can watch them grow and transform into beautiful butterflies which we can the let go. Of course as i have 2 children of my own at home one of the tanks didn't make it to work and will be staying here for our own observations ;-)

Ingitar said...

We found one of these caterpillars on our tree a few weeks ago and my delighted daughters (aged 3 and 5) are planning a dance for the butterfly when it emerges from it's crysilis and flies away... I can't wait either!
We are also watching the other crysiliss on the tree and the other caterpillars!