Monomorium minimum

School of Ants collection
Literature record

Monomorium minimum

From Dr. Eleanor's Book of Common Ants

A.K.A.: Little black ant

Size: Workers: 0.15 cm; Soldiers: 0.15 cm; Queens: 0.3 cm

Where it lives: Little black ants can make their nests outdoors, in forests or right in your back yard, often under rocks and tree bark.

What it eats: Sugary liquid called honeydew, made by small insects called aphids and scales. Also, dead insects, spiders, and your trash.

What’s the big deal?

As their common and scientific names suggest, little black ants are much smaller than many of the other ants you’ll see hanging around your house and yard. These shiny little ants are easy to spot if you know what to look for: their glossy sheen and the foraging trails they follow to and from food.

Although they’re small, these mini-bugs are prizefighters against other ant species and often bully ants over food resources. Their colonies can number more than 2,000 workers, and when a group of worker ants combine forces, their tiny stingers can pack a powerful punch to other ants. Their best combat skills are on display when they’re protecting one of their favorite foods: the sweet nectar produced by sap sucking insects, including small insects called aphids.

Aphids live on plant leaves and have mouths that are shaped like drink straws. They stab these drink straws into the leaves and suck out the juice like it’s a big milkshake. They then turn that juice into a liquid called honeydew that they excrete from their rear ends in droplets they hold high in the air, waiting for ants to come and get it.

To reach their favorite honeydew treat, little black ants travel up tree trunks and plant stems in a long line. They make the line by laying down a scented trail called a pheromone trail. That way, they only have to follow their noses to the food—or, in the case of little black ants, follow their antennae that they use for smelling.

In addition to making delicious honeydew, the aphids are tasty snacks for other insects like lacewings and ladybugs. Little black ants are scrappy fighters, though, and are able to kick out other would-be diners from their honeydew buffets even if those diners are much bigger than they are!

When it comes to fighting, little black ants have a superpower called gaster flagging. The gaster is the ant’s rear end. When little black ants are alarmed, they lift their rear ends together and vigorously wag them around in the air. While they’re wagging, they release noxious toxins. These poisons are repellent to would-be contenders and drive them away before they even engage in battle.

Sometimes little black ants make an unwelcome appearance at our breakfast tables. While they prefer to nest outdoors, their small size makes them perfect for sneaking in under windowsills, between floorboards, and through any other tiny crevasse. Inside your house, they feast on your dropped food and quench their thirst in your sink. That is why these miniscule marauders are considered a pest species.

Find out more about this species at Antweb and see more photos at Alex Wild's photography site.