W. F. Kirby, 1899
"Parktown prawn" is an ironic common name for Libanasidus vittatus, a species of king cricket endemic to Southern Africa. It is effectively unrelated to the prawns, Libanasidus being a genus in the order Orthoptera, which includes the crickets, locusts and similar animals. The king crickets are not really crickets either, but members of the family Anostostomatidae, whereas true crickets are in the family Gryllidae. The insect gets its English name from the suburb of Parktown in Johannesburg, South Africa where they are common. In Angola, it is found in the southern savanna and semi-arid regions, whereas in Namibia it is found throughout the territory. The Parktown prawn is related to the New Zealand tree wetas, which also are members of the family Anostostomatidae.
The Parktown prawn is held in low regard by many householders, but gardeners value them for controlling garden snail populations and attracting the Hadeda Ibis. The animal is omnivorous, with a diet that includes snails, other invertebrates, and vegetable matter. In urban environments, they will readily take food made available by suburban dwellers, including cat food and dog food and their droppings.
History and discovery
Libanasidus vittatus was unknown within Johannesburg before the 1960s; the first known specimen being found in Barberton in 1899 by William Forsell Kirby. They only became prevalent after 1960, when Johannesburg began to expand rapidly in size. The reason for the increase in the insects' numbers is unclear, although they have done much better in an urban environment than in the wild, and it has been suggested that some ecological controlling factor is absent in its suburban habitat.
Johannesburg, being situated on the South African highveld, has a dry climate, and therefore was an unsuitable habitat for the Parktown prawn. With the arrival of suburban dwellers, irrigated gardens provided lush, forest-like conditions, an environment more suited to king crickets. Certain suburbs in Johannesburg are considered to be some of the world's largest man-made forests, being very green and leafy, and representing a radical transformation of local flora.
The Parktown prawn is one of the larger invertebrates found around Johannesburg homes. A large specimen may grow to be 6 to 7 cm (2.8 in) or more, with long whip-like antennae extending to about the same length. The exoskeleton is orange to light brown, with darker brown or black stripes across the abdomen. The conspicuous markings probably are aposematic in effect. A large specimen can jump more than a metre high.
The male insect sports a strong set of tusk-like projections on its mandibles, although the need for them is not fully explained. It is suggested that they may be used in sexual competition between males. The female has a well-developed sword-like ovipositor, through which she will may lay between 80 and 200 eggs in damp or wet topsoil during the mating season.
Libanasidus vittatus is highly omnivorous, feeding on slugs, snails, and moth larvae such as cutworms, as well as a fairly wide range of vegetable matter. They have been seen feeding on dead birds and other carrion, the food of pet dogs and cats, pets' droppings, dry oatmeal, and also on fallen fruit. They have been known to chew on wooden floor boards and wooden structures such as garden furniture, though they are not equipped to digest sound wood.
Gardens that have a healthy population of Parktown prawns are practically free of slugs and snails, so gardeners who are aware of their habits regard Parktown prawns as an effective natural means of controlling such pests. In turn the king crickets have their own natural predators, such as the Hadeda Ibis, Fiscal Shrike and Helmeted Guineafowl, birds at home in the urban habitat and able to deal with such large insects.
Relationship with humans
Although perceptive South Africans commonly regard Parktown prawns as desirable in gardens, they can be unwelcome visitors indoors, where they are seen as pests; the insects can jump actively and often eject offensive black fecal liquids when threatened. Accordingly they frighten nervous persons and they may chew carpets and fabrics. They most often emerge into the open after rain during summer, which also is when they are likeliest to be found indoors. Commonly they are most active at night.
A popular urban legend propagated by April Fools' Day articles published by the Johannesburg newspaper The Star, has it that the Parktown prawn was the result of a genetic experiment by students from the University of the Witwatersrand in the 1960s (thus explaining the insects' sudden arrival in Johannesburg at that time). The insect's unusual size, strength and vivid orange colouring are presented as confirmation of the idea.
The resilience and strength of the Parktown prawn inspired cartoon versions in the long-running South African cartoon strip Madam & Eve. These prawns terrorised Gwen Anderson and Eve Sisulu, the lead characters. In the cartoons, the Parktown prawns get 'high' on insecticide (in reference to their size and how much poison is required to kill them), and produce two cricket-shaped indentations on the bottom of a frying pan with which they are swatted, in reference to their hard exoskeletons.
Neill Blomkamp's film District 9 features an alien race some humans disparagingly refer to as prawns. Some film critics have speculated that the appearance of the aliens was inspired by the Parktown prawn.[who?]
- Mcneil, Donald G. (24 March 1999). "These Streets Belong to the Pre-Millennium Bug". New York Times. Retrieved 26 February 2010.
- "Johannesburg's Garden Invader - The Parktown Prawn". Intekom.com. 1999. Retrieved 26 February 2010.
- "History of the Parktown Prawn". Intekom.com. 1999. Retrieved 26 February 2010.
- "Jozi's urban forest now at 10m trees, and growing". Official Website of the City of Johannesburg. 8 September 2004. Retrieved 5 October 2009.
- Alan Weaving; Mike Picker; Griffiths, Charles Llewellyn (2003). Field Guide to Insects of South Africa. New Holland Publishers, Ltd. ISBN 1-86872-713-0.
- "Appearance of the Parktown Prawn". Intekom.com. 1999. Retrieved 26 February 2010.
- "The Diet of the Parktown Prawn". Intekom.com. 1999. Retrieved 26 February 2010.
- "Dispatch Online - Your premier Eastern Cape news site". Dispatch.co.za. 30 March 2006. Retrieved 26 February 2010.[dead link]