Korva is a scroll of the internet’s best ideas.
Square-headed ants plug the nest
Army ants are so deadly that other ant species had to specialize to survive them. Fighting is so futile for some that they built their defense around a body part. Their worker classes have big square heads, and when army ants show up, those workers wedge themselves into the entrances to the nest. After a while, the attackers have to give up.
Other species take the opposite route. When they notice army ant scouts, they panic and evacuate the nest, carrying as many larvae as they can so the colony can return and rebuild after the attack.
Why do some ants have heads shaped like plugs?
Biologists call the use of the head as a door phragmosis. Doorkeeper ants such as certain Colobopsis species have heads with a flat or disc-shaped face that fits the nest opening like a cork. Turtle ants of the genus Cephalotes have similar flattened heads, and they use them to block their tunnels. The plugging worker stays in the doorway and a thick, tough head capsule absorbs the attack.
Why do fleeing ants carry larvae instead of adults?
Larvae hold the colony's future workers, and the adults have already put a great deal of energy into raising them. Many ant species haul their brood to safety when a nest is disturbed, even from threats like flooding or a collapsing nest. A colony that keeps its queen and its brood can rebuild its numbers, while adult workers can be replaced as the brood matures.