Christmas Bells

Christmas Bells
Christmas Bells - Blandfordia nobilis

Friday, January 22, 2010

Blue Triangle Butterfly

Well, you asked for photos of the Blue Triangle Butterfly (Graphium sarpedon choredon) - and it obliged by coming back today (another hot day). But you forgot to tell the Macleay Swallowtails (Graphium macleayanum) to stop harassing the poor thing. As a result, you get just some flashes of colour.
There it goes.
Damn! Missed it!
Look for the red oval marker (against the Sassafras tree on the left).
Same image cropped -
the second red ring marks the pursuing Butterfly.
If you bear with me, you will realise that these images, taken together, are clearly identifiable for what they are (which species, I mean).

But I want to publish these pathetic images anyway as they show just how hard it is to get a decent shot.
Firstly, the Blue Triangle was either unwilling to sip the nectar from my Buddlejas (but why would it be - when all the other Butterfies in the area want to drink from them?); or was unable to prevent itself from being chased off, by the Macleay Swallowtails.
Way off in the distance.
Two Butterflies circling back towards me over my neighbour's
Cypress Hedge - at a distance of about 30 metres.cropped image.
This shows the distinctive triangle patch of colour
The problems experienced by this Butterfly come down to a question of numbers, as I saw only Blue Triangle Butterfly at a time. Therefore the statistical probability is that there was only one individual present in my yard to day.

The other butterflies (of several different species) would total at least 50 individuals at any time (spread over 3 mature Buddleja plants). Of those other Butterflies, the Macleay Swallowtails are the most numerous, and the strongest and fastest fliers, and the most aggressive. The Blue Triangle is an even faster flier then the Macleay Swallowtail, but it was driven off every time it approached the Buddlejas.

After a further change in direction
the two Butterflies nearly crashed into eachother.
As a result, I got only flashes of colour - quite literally - but with such a brilliant blue colour and the shape of the colour patch - the two factors taken together are totally diagnostic.
Here is the cropped version of the previous image
the Blue Triangle is taking drastic evasive action.
Shortly afterwards, it gave up and I did not see it again.
Territorial Behaviour of Butterflies

Many people do not realise how aggressive Butterflies can be towards eachother. If there are many Butterflies around (as I am getting at present), just stand and watch their behaviour for a few minutes, and you will probably recognise this territorial behaviour for what it is.

The second "chase" (by two Macleay Swallowtails) didn't last long, but the third chase - by a single Macleay Swallowtail lasted 90 seconds without a break, and covered a circuit of some 60 metres diameter, with a lot of zig-zagging. As you can see, the chase was very intense, and obviously strenuous.

Given that Butterflies cannot actually attack eachother with weapons (sharp teeth or spurs, as we recognise amongst mammals and birds) I am not sure what they do, other than literally just harass the victim - chasing it away, or probably refusing to allow it to rest on a "Nectar tree" - one where adult Butterflies drink nectar - as distinct from "feed plants" (where the females lay eggs, so that the resultant caterpillars can eat suitable food). Many Butterfly caterpillars are highly specific in their nutritional requirements - e.g., plants of a particular genus or family.

In some species, the "territoriality" is restricted to males guarding territory from other males of the same species.

In my case documented here tonight, it is interspecific, and would appear to be related to access to nectar trees, not a matter of rivalry for mates.


Mosura said...

Blue Triangles - My favourite when I lived in N.S.W.

We get Macleays Swallowtails down here but rarely in the backyard.

Denis Wilson said...

Hi Mosura,
Glad you have happy memories of this wonderful Butterfly.
The words "flying jewel" describe my impression of this spectacular creature.
It is my first sighting (well, assuming it is the same individual seen over two days).
Apparently we are close to the lower edge of their range (160 KM south of Sydney would be around Nowra, which is the lower edge of the Sydney Sandstone geology. Beyond that, the land and plants change remarkably.

mick said...

The flash of blue is beautiful! Definitely worth recording the chase and the frustration. Given time and chance - next time might be perfect!

Denis Wilson said...

Hi Mick
yes - a flash of brilliant blue.
that's all I got, but it is almost enough.
I shall keep an eye out for more visits, but I suspect it has come down opn the hot air, and now a cool change has blown in (for which I am grateful, to be honest).

Snail said...

I admire your tenacity! Lots of butterflies here but they fly to fast and rarely settle. I've given up trying to take a photograph and just watch them through the binos.

Denis Wilson said...

Hi Snail.
This business of the Butterflies not settling intrigues me.
The Macleay's Swallowtails are greedy feeders (drinkers). But they are in the same genus (Graphium) as the Blue Triangles.
Go figure.
I assumed it is just a numbers thing, and if there were more Blue Triangles around (here) then they might get a fairer share of the nectar.
But where you are, one would assume that it is "home territory" to many of the showy species.
Cannot understand why they do not settle, when they find appropriate nectar sources.
Admittedly, those nectar sources might be the very tops of the rainforest trees (and the vines which climb them). That would make them harder to observe than the Macleay's Swallowtails on my Buddleja Bushes.
Butterflies are fascinating, but oh so hard to photograph properly.