Green Tree Ants

June 5, 2010

What a crazy couple of weeks. Amazing amounts of work to catch up on, lots of reading and to cap it all a broken tooth (with a subsequent visit to the dentist). My trip seems like a distant memory!

Anyway.. I thought I would start off by putting up a few pics of my favourite ant. The green tree ant (also called a weaver ant) is very common in its favoured habitats, across the tropics of Australia. Why do I like them? Well, to my eyes they are quite graceful, with clean lines and a great colour. Usually they are yellow/orange with a greenish tinge forward of the petiole, and have a nice rich green gaster. They are also easy to find, and easy to photograph (i.e. large, slowish, and inquisitive aggresive). The scientific name, Oecophylla smaragdina, seems to have a different pronunciation for every entomologist I speak with. I use Ee-cof-illa sma-rah-dina. Any opinions?

Green tree ants have some really interesting behaviours too, which because of the aforementioned qualities, are easy to observe. They build their nests from living leaves, which they stitch together using silk produced by the larvae. It looks literally as they they are sewing; the worker holds a larva in her mandibles and moves it back and forth over a join, while other workers hold the leaves together using their freakily sticky feet and impressive weight-holding ability (see Archetype for some great info on sticky feet, here and here). A single colony can span multiple trees, with many of these nests in varying sizes. They are great communicators, and use vibrations in addition to chemicals. Tap on a nest a few times and not only do the occupants come running, but a few minutes later you will have ants from a fair distance around the tree racing towards you (wildly spraying acid!)

They are voracious predators, as can be seen in the photo below. Lacking a sting, they ‘spread eagle’ their victim, rendering it helpless against the rather brutal butchering which follows. This gruesome scene unfolded at our kitchen window each evening, where the ants feasted upon the various bugs attracted to the window. On more than one occasion they tried to pin down small geckos too!

Like many ants, they also tend hemiterids for the sweet solution they produce in return for protection from predators.Where available, they also visit extra-floral nectaries as in the photograph below. I was surprised at how much fluid these nectaries were producing, with a new droplet forming within seconds of being consumed. You can just see the nectar drop forming on the nectary (about 1/4 of its normal quantity), just below the elbow of the ant’s right antennae.

One last thing.. if you ever find a colony of these guys in a tree, check the ground where you’re going to stand first. I stood in a feeding column while watching a nest which was at head height. Didn’t realise until I started to get nasty nasty pin-prick pains up and down my lower legs! They have a mean pair of mandibles, and to cap it off, like to spray a bit of acid in the wound!

3 Responses to “Green Tree Ants”

  1. Great pix and info – kinda wish we had those around here.

    Boy, you sure are asking for a fight with opinions on pronunciation! I agree mostly with yours, except the “d” wouldn’t be silent.

  2. Dave Says:

    These green gremlins are a real hazard when you are doing canopy work! Try holding onto a rope and a pole pruner while squirming and swatting as they scramble up your legs and down your back pinching and squirting away.

    Aren’t these the ones that flaunt the child labour laws and exploit their grubs to weave together their leaf nests? Villians!

    PS – I go for the ee-ko-PHY-la genus and always mumble the species name since I have no idea what is expected.

  3. Dave Says:

    No, Ted, you don’t want them in Missouri. i had to collect samples from at least a dozen different colonies. these ants are very defensive! Ten minutes after you’ve walked away, you get a nasty burning sensation under your clothes where an ant bit you. The best way to deal with them is to wear only spandex swimming trunks so that others can brush off the ants that inevitably get on you. But they’re still cool ants!
    @Dave, if they’re from SEAsia or Australia, then they’re O. smaragdina. If from Africa, then O. longinodis.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: