Honeypot Ants Turn Their Biggest Sisters into Jugs of Nectar

Deep in their underground nests, honeypot ants stuff members of their own colony until they look like golden water balloons. Drop by drop, worker ants deliver nectar and other liquid food into their largest sisters’ mouths. When food is scarce in the desert, the colony will feed from these living storage tanks, known as repletes.

TRANSCRIPT

Deep inside their underground nest, honeypot ants are stuffing their own kin.

The glistening globes hanging from the ceiling are actually part of the ants’ bodies. These portly ants are known as repletes. The elixir inside them will nourish the colony when food is scarce in the ants’ arid homelands in the Southwest and Mexico.

To feed a hungry nestmate, a plump replete opens its mandibles wide and regurgitates a tiny droplet that the other one slurps up. As the liquid drains, the ant’s belly deflates. The whole thing happens while the replete is hanging by the tips of its legs.

So how do these ants become living storage tanks?

It all starts with this giantess – the queen. All these workers are her daughters.

She lays thousands of tiny white eggs. Workers tend to them as they grow into squirming larvae and then pupae wrapped in fuzzy cocoons.

They choose the biggest newborns to stuff until they swell into repletes.

To fill them up, workers venture out at night to forage. Dead insects provide protein and fat. Desert plants give them sweet nectar. Or dinner might be red artificial nectar, if a human is keeping the ants as pets.

Workers carry the nectar back. And they feed it, drop by drop, to their sisters, the ones they’re turning into repletes. They make up about one fifth of the colony.

The nectar flows into a pouch called the crop. The crop will swell into a storage tank because valves prevent most of the liquid from flowing into the stomach, where it would be digested.

As their belly grows, this flexible membrane stretches. The hard sclerites that protect the ant’s abdomen move away from one another, until they end up like a chain of islands on a tiny planet.

Suspending themselves allows the air to circulate around them, maybe preventing a fungi attack.

To our human eyes, these living chandeliers might seem like captives, hanging in the dark for weeks or months. Or it might look like they have it easy, just chilling while droplets are lovingly delivered.

The truth is that every worker in a colony has a key job. And all of them, even a replete in its cozy home, can face a sudden demise … by a badger that digs up the nest … or someone delighting in a special treat, as humans have done for thousands of years.

Gabriela: Mmm.

Hi, this is Lesley McClurg. I’m a health and science reporter. I’m standing in for Laura until the summer.

Repletes are so delicate, they sometimes spring a leak. And the other ants just drink from the cut. Thirsty for more Deep Look? Watch this episode about how mosquitoes use six needles to suck your blood. See you next time.