Insect

The island had no mammals or reptiles and few birds. In the absence of competitors, insects had occupied the vacant evolutionary niches. There were insect scavengers and nut-hoarders. Herbivorous insects and large, predatory insects that hunted them. Solitary insects and insects that lived in colonies. Nocturnal insects and insects that fed on sunlight. And, on the insects, lived other, parasitical, insects.
The island achieved a small degree of scientific note and, almost inevitably, a visiting Naturalist's expedition introduced rats to the island.

When the next scientific survey was carried out, some years later, the island had thousands of rats. Some were kept for food, farmed by insects. Others carried insect riders.