Asian Weaver Ant

Oecophylla smaragdina is one of two extant weaver-ant species (the other is the African O. longinoda). Both have evolved an extraordinary nest-building strategy. Adult workers cannot produce silk — only the larvae can. So colonies build their tree-canopy nests cooperatively: chains of workers grip the edges of leaves and pull them together, while OTHER workers walk through the chain carrying mature larvae, gently squeezing each larva so it extrudes silk that bonds the leaves together. The larvae are deliberately used as living glue guns. The resulting nests are silvery-green leaf-and-silk structures the size of a basketball, with large colonies maintaining hundreds of nests across multiple trees. Vietnamese, Thai, and Chinese citrus farmers have used weaver ant colonies as biological pest control for at least 1,500 years — the colonies aggressively defend their tree from any other insect, providing free protection for the crop. The practice continues today and is recognized by the FAO as the world's oldest documented biological control system. Adult weaver ants are also collected and sold as a delicacy across Southeast Asia, often eaten with sticky rice for their tangy, lemony flavor (formic acid).