Insects & arachnids

Leafcutter ant

Atta cephalotes

A line of leafcutter ants carrying cut pieces of green leaf along a branch

Photo: Pjt56 · CC BY-SA 4.0 · via Wikimedia Commons

Where
Your garden, Dry forest, Coco town
When
Dusk and night, all year, busiest in the green season
Size
Workers 2 to 15 mm, the soldiers noticeably bigger
Should I worry
Enjoy it
Harmless to you. Not to your garden. The soldiers can pinch if handled.

Look down on any evening walk and you will cross one: a moving ribbon of ants a few centimetres wide, each carrying a cut piece of leaf several times its own size, all heading the same way.

Where you’ll see it

Gardens, roadsides and forest floor everywhere on this coast. The nests are large mounds of excavated soil, sometimes metres across, and the trails from them can run a long way.

What to know

Leafcutters are farmers. The leaves feed a fungus in underground chambers and the fungus feeds the colony. That is why they take the tender new growth: it makes the best compost. A colony can strip a favourite shrub in a night and be gone by morning.

They do not bite unless handled and they are not interested in your house. The only real war is over the garden, and the ants have been at it longer.

Questions people ask about this one

Why are the ants carrying leaves?

They do not eat the leaves. They carry them underground to feed a fungus, and the colony eats the fungus. A single colony can hold millions of ants and clear a surprising amount of foliage in a night.

How do I stop leafcutter ants eating my plants?

Find the trail and follow it to the nest, which will be a mound of loose soil. The realistic options are to protect prized plants with a barrier at the base or to live with the loss. Poisoning the nest rarely works for long and takes out much else.

Wondering what else is out there?

Ask me on the call. I'll tell you what actually shows up in a Coco garden, what to do about it, and the one guy everyone rings when there's a boa in the roof.

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