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DISPLAYING POSTS FROM: Dec 2012 (7)

Bug of the Month - Giant Grasshopper

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by Patrick
Publish date
3 December 2012
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The Giant Grasshopper is so named for being the largest grasshopper in Australia. The adult's body length, however, varies from an enormous 90mm to less than half that size. This gives it the scientific name Valanga irregularis, referring not only to the irregular colouration but also the irregular length. People who know the species well simply call it Valanga.

grey grasshopper The mottled grey form of the Giant Grasshopper, common around Townsville, North Queensland.
Image: Patrick Honan
Source: Museum Victoria
 

Unlike many of the better-known grasshoppers, this species feeds not on grass but on the leaves of shrubs and trees. They have a very variable diet, ranging from native plants to citrus, cotton, coconut and even coffee plants. This makes them a minor pest in some areas, due to their occasional habit of consuming every leaf on a food plant when present in large numbers.

brown grasshpper The spectacular brown version of the Giant Grasshopper common around Iron Range, North Queensland.
Image: Patrick Honan
Source: Museum Victoria
 

Giant Grasshopper nymphs change colour with each moult, varying from light green to a spectacular red with blue stripes. The eggs are laid in batches of up to 150 within 'pods', made of a frothy substance that hardens upon drying. The eggs are sometimes attacked by a tiny parasitic wasp (Scelio flavicornis), which lays its own eggs inside the grasshopper's eggs, the wasp grubs feeding on the embryo within.

Brown and green forms of immature Giant Grasshopper Left: A young nymph. Right: An older bright green nymph.
Image: Patrick Honan
Source: Museum Victoria
 

Adult grasshoppers are very sensitive to movement and will leap away at the slightest disturbance. They can fly upwards as high as two metres, then horizontally in a straight line until they hit the ground. However, Giant Grasshoppers tire easily and the length decreases rapidly with each consecutive leap.

face of Giant Grasshopper A close encounter with a Giant Grasshopper from the Northern Territory.
Image: Patrick Honan
Source: Museum Victoria
 

Giant Grasshoppers occur across the top of Australia and there are a number of closely related species, at least four of which are undescribed. They are all very difficult to distinguish from each other, due to variations in most of the important characteristics, including size.

Giant Grasshopper eating A captive adult Giant Grasshopper satisfies its ravenous appetite with Orthopteran mix.
Image: Patrick Honan
Source: Museum Victoria
 

This species survives very well in captivity, feeding on a combination of fish flakes, grass seed, muesli, and pollen (known as Orthopteran mix). Unlike other insect species, they show no signs of inbreeding – a single mated female may be sole progenitor to tens of thousands of descendants over many generations without a single sign of genetic deformities.

exhibition display cases The Habitats exhibit, home of the Giant Grasshopper and many other spectacular creatures in Bugs Alive!
Source: Museum Victoria
 

Giant Grasshoppers can be seen in the Habitats exhibit in Bugs Alive! at Melbourne Museum.

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