But even more incredible is that our count was done on surface ants only. Many other ants in a colony, including the queen, live deeper underground. We have no idea what their numbers might be here. Non-native ants are one of the few animals that can quickly and completely break an ecosystem.
Ants are incredibly effective and efficient predators and have few limits on their diet.
They'll eat anything that doesn't have a defense. And because on Kure, these alien ants have no natural predators to control their population, as long as they can find food, their colonies will probably continue to grow. Their strong presence on the island may explain why it was so difficult to find very many insects on the island. Native insects would have no defenses against these ants, therefore would be easy prey and their astonishing numbers here would probably affect even non-native species. To complicate matters, these alien ants feed on the nectar of another introduced insect, a scale that is also very common on island.