December 2019

Fancy flier sports plush posterior

This unusual insect landed near us. What is it, and why does it have such a fancy brush on its abdomen?


Male Bird of Paradise flies, like their fabulous namesakes in New Guinea, spot elaborate plumes. Photo courtesy of Cheryl Ellis.

This flamboyant insect is a male ‘Bird of Paradise Fly’ (a species of Callipappus), in the Family Callipappidae. Despite the name, these are not actually flies. They belong to a group of insects called the True Bugs (Order Hemiptera), which are characterised by having straw-like mouthparts adapted for sucking liquids. More famous members of the true bug family include cicadas and aphids. Like most hemipterans, callipappids feed on plant sap. Unlike most hemipterans, immature callipappids form a limbless ‘cyst’ while feeding on subterranean plant roots. Relatively little is known about this stage in their life cycle, but we know that some species feed on the roots of Banksia in sandy soils.

Bird of Paradise Flies take their name from the extravagant plumes of wax filaments sprouting from the abdomens of males, much like the exotic feathers adorning actual birds of paradise in New Guinea. Females look nothing like the males. They are up to four times larger, and resemble plump, flattened grey grubs with long antennae, short legs and no wings. They do not feed, and cling, barely mobile, to plant stems. Males have a single pair of wings, red to purplish bodies, well-developed legs, and an abdominal tuft of white waxy filaments. Such extreme variation between the sexes is common in the insect world, with males and females looking like completely different species. This phenomenon is called sexual dimorphism.

Male Bird of Paradise Flies fly about in search of females, presumably following a trail of attractant chemicals called pheromones. In some cases many males will converge on one female. After mating the males die, while the females lay hundreds of eggs. Females of some Callipappus species have a pouch called a ‘marsupium’ in which to carry the eggs. In others the eggs develop inside the female. After she has died, they actually emerge from her corpse.

And the purpose of those splendid glassy wax plumes? While that remains one of life’s mysteries, the suggestion is that they stabilise flight. 

Want to know more? Our Discovery Centre is a free service open seven days per week, with experts ready to answer your questions. You can phone, write, contact us via our website or pop in. If we don’t know the answer we will try to find out for you.

The exact function of the tail-plumes is still unknown. Photo courtesy of Steve Wilson.

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