Jalmenus evagoras
Description
The Imperial Hairstreak (also known as the Common Imperial Blue) is a small butterfly with a wing span to 22mm. It usually flies close to the ground and occurs in open eucalypt forests and woodlands with acacia (i.e. wattle) understorey. Adults show distinctive underwing markings and pale blue upperwings, with a blackish margin typical of many hairstreak butterflies.
The black caterpillars are usually found feeding on acacias. The best way to find the caterpillars is to follow the trail of ants along the branches of one of these plants.
Adaptations
- Imperial Hairstreak butterflies have a mutualism relationship (where both species benefit) with some species of ant (Iridomyrmex) - caterpillars provide sugar for the ant and the ants protect the caterpillar from predators
- Adult butterflies have a thin tail on the base of each hind wing that looks similar to antennae, which is thought to confuse predators
Feeding relationships
- What I eat: various wattle leaves (e.g. Acacia concurrens, Acacia leiocalyx)
- What eats me: spiders, insectivorous birds (e.g. butcher bird, magpie)
Interesting facts
Ants swarm and surround the caterpillars of the Common Imperial Blue butterfly, eating the honeydew (sugar) that they produce. In return the ants guard the caterpillars and protect them from predators.
Acknowledgements: Butterflies of Coastal SEQ, Australian Museum