Trophallaxis

Trophallaxis is how ants share food with each other. When a forager drinks honeydew, nectar or sugar water, most of it doesn't go to her own digestion. It goes into a special storage pouch called the crop, often nicknamed the "social stomach". Back in the nest, she brings the food back up and passes it mouth to mouth to her nestmates.

That's the reason people say ants have two stomachs: one to digest their own food, and one to carry food for the rest of the colony. A valve between the two lets each ant decide how much to keep for herself and how much to share.

Thanks to trophallaxis, only a small part of the colony needs to go outside, while the queen, the nurses and the larvae get fed without ever leaving the nest. It's also a way for ants to exchange chemical signals, which helps keep the colony connected.

In practice

• Don't worry if only a few ants come to the feeder. They're filling their crops for everyone else.
• If you watch closely in a well-fed colony, you'll often spot two ants face to face, passing a drop of liquid between their mandibles.
• Offer liquids in a liquid feeder or a small drop, so workers can drink without drowning.
• Trophallaxis spreads whatever is in the food, so keep sugar water fresh and never use anything containing pesticides.