My observations with odontomachus

[Nylanderiafulva]

Odontomachus are an interesting combination of common and reclusive. In warm habitats they can be found anywhere with leaf litter. Even if you expose the nest, they are very reluctant to defend despite having a sting that, in my experience, is almost the same as a yellowjacket, even a little more painful. They prefer retreating into their deep nest and moving the brood away. By no means do they pour out and defend like C. floridanus or S. invicta, despite having a pretty large colony size. So they have impressive weaponry and numbers, and yet they choose to evacuate in the event of an attack.

This strategy is actually much more effective than you might think, and their method of defending against other ant colonies is genius. Though they back down in the face of large predators, they don't sit there and take it from other ants. As their name suggests, trap-jaw ants (odontomachus) have jaw blades they can spread to 180 degrees, ready to snap shut at hundreds of miles an hour on whatever they should choose to strike. It is this that they use to kill prey, almost never administering a sting. They use their lightning-fast bite to pop holes in prey and wait for it to bleed out. Additionally, they can strike the ground to launch themselves into the air. And they use this to great effect when fighting.

I had the good fortune of seeing a midsized odontomachus nest in a territorial dispute with a RIFA colony, and a large colony fighting off a C. floridanus raid. What they did on both occasions was kill scouts in order to slow the advance, and then evacuate, leaving the colony to occupy the old nest. When fighting individual ants, the trap-jaws would work either singly or in pairs. RIFA scouts were snipped in half. They'd keep distance from camponotus majors and snip off antennae, leaving the ant disoriented. Before it could run to its colony, one would keep the major distracted while the other cut legs from behind. Finally, they'd administer a sting. The whole process took less than 30 seconds and made it impossible for the major to bring any of its weaponry to bear (powerful jaws, formic acid). It's more or less a fair fight for trap-jaws against camponotus minors, and because the trap-jaws are more aggressive, they actually tend to get hurt more fighting majors that minors.

However, the odontomachus' reclusivity and their avoidance of conflict really has some merit, and other colonies seldom attack them. Because workers tend to roam far and in all directions, it is difficult to locate the nest. Predators such as lizards almost never find them because they never forage in the open. They kill prey quickly (they mostly prey on insects, staying away from food sources other ants typically consume) and leave no opportunity for fights over a kill. Simply put, they don't go looking for trouble and they don't get it. That is, unless another trap-jaw ant colony is involved.

You may be asking yourself at this point, why is the sting so potent if they never use it? Partly for protection from predators, but mostly for intra-species combat. Seldom do queens cooperate, and more often than not they wind up killing each other. 2 queens may occasionally work together, but no more than that and most of the time they fight. What usually happens it that after circling and taking snaps at one another, one will launch itself forward and the other will either flee or stand its ground and bring its stinger to bear. A sting in the abdomen is fatal, but it usually takes about 1-2 second for the sting to be administered. The stinger is most deadly when one ant is on its back or one ant has succeeded in getting on the other's back. These conflicts are rare but they do happen, especially when both ants are close to their nests. They are most common among queens, who are larger and stronger than workers (but still have the same basic body shape) fighting for a spot to found. This is why 2-queen polygyny sometimes exists, because it allows two queens to fight off a competitor fairly easily. One leg snip from behind usually means death for an opponent. This is the reason the odonotomachus fight strategy works so well in pairs.

In captivity I'd consider this an intermediate species. Due to their comparatively large size they found rather slowly, getting their first workers at around 6 weeks after founding. They are semi claustral and rather picky with food, preferring a more insectivorous diet than most other ants but eating more sugary foods as the colony ages. At founding they need 100% insects, with first workers 90% insects and 10% sugary, and moving more towards half and half as the colony grows bigger. The colony usually gets to around 1000 workers, but gets to around 3000 with two queens. Queens live about 7 years and I have heard of reproductive workers but never actually tried it myself. Knowing how primitive these ants are (they don't have social stomachs, just like Myrmecia) it would probably work. For whatever reason the queen have a weird tendency to die 1 or 2 days after capture, but if they survive after that period they're usually fine. They like tight spaces, so don't be too free with space. Fairly large but snug tunnels are appreciated, and a full size colony is quite comfortable in an AC formica hybrid nest. You can work freely in their outworld, workers will retreat to the nest if frightened, but go near the nest and you will get a sting. They launch themselves into the air at will, so be prepared to dodge some ants if you clean around their nest. They are also quite messy, and develop a lot of mold in their nest, so every month I like to move them from one nest to another while I clean their former one, moving them into the now clean one once their other gets dirty.

All in all, an interesting and quirky intermediate species that are great fun to feed. Would recommend them to anyone who can get their hands on a queen.

[Tramonta]

Thanks for the very nice and informative text.

I am a beginner ant keeper, but I came across two Odontomachus queens in three days. They just appeared at my home after raining days.
The question I have is, do the queen need an outworld right at the start? or the tube work just fine?

Thanks for the interesting text, especially regarding their diet and nest space.