Bull ants have right eye for the job

Worker bull ants have military-style night vision, while their higher status winged nest mates see best during the day, Australian researchers have discovered.

The research led by Dr Ajay Narendra from the Australian National University and colleagues is published this week in the Proceedings of the Royal Society B.

It is the first research to show that individual ants of the same species living in the same colony have huge variation in the structure of their eyes, depending on what job they do and when they do it.

A colony of bull ants contains three types or castes: sterile female workers who forage on the ground, fertile females who briefly fly then live in the dark nest as queens for up to 15 years, and winged fertile males who have a short life on the wing searching for a queen to mate with, before dying.

Biologists already puzzle over how a single colony of genetically identical ants can have such different body shapes. But now it seems even the fine structure of the eye can show dramatic variation.

The team studied four different species of bull ant (Myrmecia) living in eucalypt forests on the outskirts of Canberra.

They recorded at what time of day or night each caste member of each species was active. They then preserved the eyes of the insects and examined the fine structure under a microscope.