Wednesday, 6 July 2011

The Weaver Ant-Mimicking Jumping Spider Up Close and Personal

Meet the half ant, half jumping spider, and totally mean, Weaver Ant-Mimicking Jumping Spider Myrmarachne plataleoides that I photographed in my home garden yesterday.

As soon as I stumbled it, I could see through its cunning disguise by noting that it had four pairs of legs like in a spider, as opposed to three pairs of legs like a plain vanilla ant. The elongate body size meant it was a male of this jumping spider.

Contributing to its elongate design was its long protruding spatulate “jaws”—the ends of which were fitted with a pair of needle-sharp fangs that could deliver a fatal stabbing to its victims.

The males, having gone for this extravagant secondary sexual adornment of looking front-heavy to impress the gals, and to intimidate rivals, have dispensed with venom in the fangs altogether.

So with no venom, they use their heavy machinery in front to overpower their prey first, before stabbing them repeatedly with their needle sharp fangs to suck their juices. Often while the victim is still alive.
The females of this species, on the other hand, having settled for a simpler body design—looking strikingly similar to a typical Weaver Ant Oecophylla smaragdina ("Dimiya")—have retained potent venom in their fangs. And they inject it to incapacitate their victims first, before drinking the liquefied juices thereafter, the regular way.
Those gleaming cute eyes that you see at the proximal sides of the male’s oversized “jaws” are fakes to make it appear like an ant.

It’s real jumper eyes—four pairs of them—are situated further back, where its actual head is placed.

The appearance of the male looks remarkably like a larger Weaver Ant carrying a smaller cousin. Which in real Weaver Ant world is a done thing, with major workers transporting minor workers in their complex social structure to fulfill various daily duties. So this physical appearance of the males also copies a vocational behaviour of the Weaver Ants in an ever so clever way.

This jumper was found in an endemic "Wal-idda" tree, which is peculiarly named in botany as Walidda antidysenterica. This tree had a fair number of Weaver Ants that this jumping spider was trying to copy.

Underneath the leaves, this tree also had a fair number of scaled insects, which feed on plant juices, sucking them directly from the plant's vascular system. After doing that, they pass out a honeydew—a sugary excretion, which the many species of ants, including Weaver Ants, find irresistible.

So this explains the presence of Weaver Ants and the Weaver-Ant-mimicking jumping spider on the same tree. As many other species of ants, Weaver Ants mainly prey on small insects, and turn to honeydew offerings of leaf-dwelling insects to supplement their diet with more carbohydrates. These sugar addicts drawn to trees infested with scaled insects in return give these defenseless insects with much needed protection from their natural predators such as lady bugs and hover flies. 

The "Wal-idda" tree in question had no Weaver Ant nests. As a result, the ants were less temperamental and gave me no trouble. Of course there were warnings given by the odd individual with its "cutting edge" mandibles agape to intimidate me.

Photographing jumpers is challenging business because they are too jerky and jumpy, resulting in pictures with the subject badly composed, blurred, or missing altogether! The other thing is they jump on to the lens and the flash heads when you get too close.

Compared with all of them, I found Myrmarachne plataleoides incredibly easy to work with because it was very calm in its disposition. It was slow and confident, just like an undisturbed Weaver Ant.


GG said...

...I think I'm in love with your camera..!
amazing stuff Amila. And really fascinating facts. Didn't know spiders can be such colourful characters.

Stuart Price said...

I've had nasty experiences with ants in various you tell me some of 'em can JUMP?

Amila Suwa said...

Aloha, Sasani!
Long time no comment. Very nice to hear from you. And thank you!
Spiders are pretty little beasts. :)

Haha, may be!
This one is less of a jumper, remember.

Phil Slade said...

Tremendous story and factual information Amila, not to mention the pictures. I suppose the obvious question to arachnaphobes is "Do they bite humans and does it hurt"?

Amila Suwa said...

Thanks, Phil.
The male of this spider having got no venom and is not a threat to humans at all; its female is too small to hurt humans. Besides, this species of jumper stays in company with Weaver Ants, which are generally avoided by humans because of their notorious habits.

Monique et Daniel said...

Photos et reportage très professionnel, merci pour le partage ! nous n'avons jamais vu votre "jumping spider" (pic 1)/ tres impressionnant !

Amila Suwa said...

Merci beaucoup, Monique et Daniel !

Je suis à l'affût pour la femelle de cette araignée à photographier. Sauf si vous observez attentivement, il est difficile à détecter chez les fourmis tisserandes. Hier, j'ai photographié un travailleur majeurs Ant Weaver transporter un travailleur mineur !

rainfield61 said...

The jumper is great!!

I first thought it is a weaver ant before reading you post.

But calculation on the number of leg tells me differently.

It never looks like a spider.

flowergirl said...

Oof! What a wonderful post!

Amila Suwa said...

Nice to hear from you, Rainfield.
From what I have heard, this spider occurs in Peninsular Malaysia too. So be on the look out. :)

Thanks a lot, Flowergirl.
Glad you think so!

Kirigalpoththa said...

Amazing camera work!

I always had difficulties differentiating these two species.

Amila Suwa said...

Thanks, K!
Yes, they are very much alike.

Anonymous said...

Amila, I could not take it in a single gulp. All I can say is Wow. Brilliant photos and description.

Amila Suwa said...

Hey, Magerata. Thanks a lot!
It's always nice to hear from you, sir!

There should be a part 2 for this post, once I could photograph its female. It has so far proven to be elusive.

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