Colobopsis macrocephala

Introduction

Colobopsis macrocephala is a small Australian ant belonging to the Formicinae subfamily. Major workers measure approximately 6-6.7mm in total length, with a distinctive truncated (flattened) front to the head - a phragmotic adaptation that allows them to plug nest entrances like living corks . The species is dimorphic, meaning there are clearly separated major and minor worker castes with no intermediate sizes. Coloration is yellowish-brown to brown, with the fore femurs noticeably swollen compared to other leg segments. This species nests in branches and twigs of trees and shrubs across eastern Australia and Tasmania . What makes this species interesting is its specialized head morphology - major workers use their flattened, truncated head as a living door to seal the nest entrance, a behavior that protects the colony from predators and weather. This cork-like plugging behavior is rare among ants and makes observing them particularly rewarding for keepers.