Common Western Hangingfly

by Dr Nihara Gunawardene
in Blog
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Species in focus: Common Western Hangingfly

Mecoptera: Bittacidae: Harpobittacus similis

During a recent survey of a wetland south of Perth, we regularly encountered a large orange fly-looking insect hanging from the end of twigs. Initially we thought it might have been a fly or a wasp having a rest on a twig but after observing their gentle take-off, we realised we were not looking at either a wasp or a fly but in fact another flying insect, the Common Western Hangingfly.

Harpobittacus similis is a bright orange, large flying insect native to the south west of Western Australia. It belongs to a family of Mecoptera (Scorpionflies and Hangingflies), which is an Order of insects found throughout the world. Scorpionflies or Hangingflies are predatory insects generally named for their distinctive abdomens which make them appear similar to the eponymous arachnid. However, they are not true flies (Diptera) but are often mistaken as flies due to their long wings and mouth parts. The Bittacidae Family are called hangingflies due to their habit of hanging from vegetation to catch prey. Their elongated legs with modified predatory claws allow them to grasp at small insects flying past. They then insert their proboscis into the prey and feed on its body fluids.

The Common Western Scorpionfly is well-known for its mating behaviour of males providing nuptial gifts to females prior to copulation. They are easily observed due to their large size and bright colouration. Males commonly hang from vegetation proffering gifts of insect prey they captured while sending out pheromonal signals to nearby females. Research has shown that females choose mates according to the size of the insect prey offered and copulation duration is related to the size of the gift (Bornemissza 1966, Gwynne 1984). So at least, in this world of the Common Western Hangingfly, size most certainly does matter.

 

Photo credit: https://www.friendsofqueensparkbushland.org.au/harpobittacus-similis/ (S. Mawson)

 

References

Bornemissza, G.ZF. (1966). Observation on the hunting and mating behaviours of two species of scorpionflies (Bittacidae: Mecoptera). Australian Journal of Zoology, 14:371-382.

Gwynne, D.T. (1984). Nuptial feeding behaviour and female choice of mates in Harpobittacus similis (Mecoptera: Bittacidae). Journal of the Australian Entomological Society, 23: 271-276.