Ant gland which secretes honeydew when the ants massage them. Some caterpillars produce vibrations and sounds that are perceived by the ants. A similar adaptation can be seen in Grizzled skipper butterflies that emit vibrations by expanding their wings in order to communicate with ants, which are natural predators of these butterflies. Other caterpillars have evolved from ant-loving to ant-eating: these myrmecophagous caterpillars secrete a pheromone that makes the ants act as if the caterpillar is one of their own larvae. The caterpillar is then taken into the ant nest where it feeds on the ant larvae. A number of specialized
Green-head ant they prefer. This suggests that the cost of moving to a suitable nesting site outweighs the benefits of moving to a larger rock. A large expenditure of energy is required for a move: scouts must first find a suitable site, brood must be transported safely, and the colony is exposed to an increased risk of predation. Nest abandonment by the green-head ant varies, but peaks during summer. Like other temperate species, activity in colonies is greatly reduced during the colder months, which may be the reason there is a high proportion of nest abandonment during summer. Nests abandoned by green-head