My Job as an Ant Caterer

Most of us have fed ants before. Maybe you’ve left your picnic unattended and you returned to see some uninvited guests. Or you left a plate of cookies on your table and later found some hard-working ants bringing food back to their family. (That one’s from personal experience.) Fortunately, it turns out that my dessert’s sacrifice was not in vain. Due to my extensive experience in having my food occasionally stolen by opportunistic ants, I’ve been promoted to the role of official ant caterer.

A day in the lab

It’s Wednesday afternoon, which means that it’s time to feed the ants. I enter the lab through this door:

Bee Lab does study turtle ants (genus Cephalotes), but despite what these drawings suggest, our turtle ants are 100% ant and 0% turtle. Art credit: Fletcher Nickerson.

Upon entering the lab, I rock the bottle of fluon back and forth so that the solids in the solution don’t congeal at the bottom. Fluon is a slippery substance that we paint onto our ant habitats so that (in theory) the ants can’t climb to their freedom. What you’ll see shortly is that ants are incredibly persistent and come up with creative solutions.

After that, I check on the ants. On the middle shelf in the picture below, you’ll see nine boxes. Eight of them are colonies of turtle ants (Cephalotes varians). One box in the back, labeled “marshmallow”, houses Mexican twig ants (Pseudomyrmex gracilis).

Food preparation

I set out clean food containers for this week’s feeding. Nine microscope slides (glass rectangles), nine small bottles, three large bottles, and nine dishes.

On the glass slides, I place nutrient-soaked paper towels. Each piece of paper towel is dipped in one of the following: 3% sugar solution plus ¼ of a multivitamin tablet, 3% urea solution, or 3% salt solution. Unlike the fluon, these solutions can be easily prepared in our lab, so I just make more when I run out.

Let’s go to the fridge to retrieve the ant food.

Don’t worry about the “biohazard” and “cancer hazard” stickers! All of the bio department fridges have these regardless of what’s stored in the fridge. There’s nothing hazardous in this one.

Each folded paper towel piece needs just a quick dip in the solution.

I fill the small plastic bottles with 3% sugar solution. The large bottles are just tap water. Wicks are stuck through the caps so that they slowly dispense the liquids.

To the plates, I add a bit of pollen and ground-up cricket. The turtle ants don’t show any interest in the cricket, but the twig ants do eat it, so I add a heaping helping of cricket to Marshmallow’s dish.

Now that the plating is complete, I’m ready to exchange the old containers for the new.

Food delivery

Changing out the food in the ant habitats is a (slightly) more harrowing task than you may think. While removing the old food is simple enough, the tricky part is to make sure that any hitchhiking ants go back into the box.

The twig ants

I always feed Marshmallow first since they’re the most challenging to deal with. Twig ants move exceptionally quickly, and once they get a taste of freedom they will beeline (wrong pun) for it.

A battle is about to unfold...

Photo by Matina Donaldson-Matasci. Look, there’s a twig ant climbing the wall on the right side near the microscope slide.

When I take the lid off, I flip it over to check for aspiring escapees. The walls and the lid are both fluon-ed, but it seems like the twig ants chew little holes in the fluon to create footholds. It’s impressive but concerning. And while I have the box open for feeding, I usually see one or two twig ants marching along the rim of the box like they’re patrolling for tasty tidbits outside of their confinements.

Photo by Matina Donaldson-Matasci.

When I spot ants on the food container that I’m changing out, I use paintbrushes to flick them back into the box.

Photo by Matina Donaldson-Matasci.

With the twig ants, this task is often easier said than done. They climb surprisingly quickly, which has led to some dicey situations. I can only devote my attention to one ant at a time, but I often need to wrangle multiple ants at once. For example, there are usually multiple ants on the microscope slide that I’m changing out. Or sometimes I see an ant outside of the box while I’m holding something with ants on it. These circumstances provide the perfect opportunity for a twig ant escape artist to climb up the paintbrush and onto my arm.

Jailbreak. Photo by Matina Donaldson-Matasci.

Fun fact: twig ants slow down when they’re cold. Prof Donaldson-Matasci has suggested that I put Marshmallow in the fridge for a minute so that the ants will be easier to handle. I have employed this strategy a few times. I feel bad about doing it, but it’s probably on par with standing in a Costco walk-in freezer… or so I tell myself.

The turtle ants

While it's nerve-wracking to change the twig ants’ food, it’s much easier to do for turtle ants since they move so slowly. They also don’t put holes in the fluon or climb up the walls. In terms of physique, turtle ants are chunkier and smaller than twig ants, so they’re easy to tell apart from each other.

Here’s a look into a turtle ant colony. While the food setup is much the same as it is for the twig ants, there are some key differences in the habitats. For instance, we’ve provided red plastic tubes for the turtle ants to use as nests, which we didn’t do for the twig ants. Also, the floor has much less debris. There are a fair amount of dead ants in there (which is hard to tell from this photo, though you might be able to spot a few that are curled up on their sides or backs), but living turtle ants will carry the bodies to one side of the habitat as long as the bodies are on the floor*.

*Every week I spot several dead ants in the food dish, among the pollen and cricket bits. The ones you see inside the dish, but not along its rim, are probably dead. I don’t know how long they stay in there before they’re dragged out (if at all). I’ve never seen a dead twig ant in the food dish though. Maybe the turtle ants aren’t bothered by dead bodies in their food source?

Wrap-up

After I finish changing out the food, I do a lot of washing and scrubbing.

I make sure to fill the humidifier, and… that’s it. After looking around to make sure that everything is in its place, I leave. I check my arms again for good measure. If I think I feel something moving around on my arms later that day, I check them again. Ants can take you by surprise, after all.

Conclusion

There’s an irony to this situation. Ants are capable scavengers when left to their own devices. It makes logical sense that we must go out of our way to feed our captive ants, but doesn’t it seem strange? Then again, our relationship with dogs and cats is much the same way. I wonder if it’s possible to domesticate the turtle ant...