''Valanga irregularis'' (common name "giant grasshopper", "giant valanga" or "hedge grasshopper") belongs to the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Acrididae Acrididae are the predominant family of grasshoppers, comprising some 10,000 of the 11,000 species of the entire suborder Caelifera. The Acrididae are best known because all locusts (swarming grasshoppers) are of the Acrididae. The subfamily Oedi ...

. The distribution is restricted in the

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

n tropics and subtropics. The species is the largest grasshopper of the continent. Usually the animal lives a solitary mode of life.

Description

Both sexes look similar but differ in body size. Female individuals can reach up to 60 to 75 millimetres in length, males about 45 to 55 millimetres, hence they count as the largest grasshopper in Australia and in Southern African countries. Some reports refer a body length up to 90 millimetres. The body colour and pattern varies highly. Adults have a creamy brown to greyish green colouring. The

forewings Insect wings are adult outgrowths of the insect exoskeleton that enable insect flight, insects to fly. They are found on the second and third Thorax (insect anatomy), thoracic segments (the mesothorax and metathorax), and the two pairs are often ...

show a black dot pattern, the hindwings are dark grey, sometimes also colourless or light green. At the

tibia The tibia (; : tibiae or tibias), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two Leg bones, bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outsi ...

orange and red spines with black stings are visible.

Distribution

''Valanga irregularis'' is native in the tropic and subtropic regions of Australia, northward of

Sydney Sydney is the capital city of the States and territories of Australia, state of New South Wales and the List of cities in Australia by population, most populous city in Australia. Located on Australia's east coast, the metropolis surrounds Syd ...

. The species favours a moist climate. In spring and autumn they are often found in grassland or forest. If the atmospheric conditions are ideal they sometimes leave for suburban gardens.

Ecology

''Valanga irregularis'' feeds on shrubs, in particular Acalypha,

Hibiscus ''Hibiscus'' is a genus of flowering plants in the Malva, mallow family, Malvaceae. The genus is quite large, comprising List of Hibiscus species, several hundred species that are Native plant, native to warm temperate, Subtropics, subtropical ...

Bauhinia ''Bauhinia'' () is a large genus of flowering plants in the subfamily Cercidoideae and tribe Bauhinieae, in the large flowering plant family Fabaceae, with a pantropical distribution. The genus was named after the Bauhin brothers Gaspard and ...

. Another food source are palm trees (

Arecaceae The Arecaceae () is a family (biology), family of perennial plant, perennial, flowering plants in the Monocotyledon, monocot order Arecales. Their growth form can be climbing palm, climbers, shrubs, tree-like and stemless plants, all commonly k ...

). They possess strong

mandibles In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone i ...

which are used to eat the plant beginning from the leaf margin. The feeding takes place all night long and they remain hidden behind branches during hot and rainy days. Adult individuals are good jumpers and can defend against predators like

mantis Mantises are an order (Mantodea) of insects that contains over 2,400 species in about 460 genera in 33 families. The largest family is the Mantidae ("mantids"). Mantises are distributed worldwide in temperate a ...

es (Mantodea) or lynx spiders with the spines on the hindlegs. Moreover, ''Valanga irregularis'' is well camouflaged as the body colour resembles the plant stem and leaf they are hiding behind. ''Valanga irregularis'' mostly lives in solitude and does not form swarms. However, under favourable conditions, they may set up in small groups and may cause damage as for instance on young coffee berries. Nevertheless, the species does not count as an ecological

vermin Vermin (colloquially varmint(s) or varmit(s)) are pests or nuisance animals that spread diseases and destroy crops, livestock, and property. Since the term is defined in relation to human activities, which species are included vary by regi ...

. Adults generally spend the winter months in their hideout but they remain not completely inactive as they leave their lair from time to time for eating or sunbathing. The mating season begins in the first warm spring days. The males call the females with noises and they typically meet on the food supply.

Development

Copulation Each year one generation is bred. The life cycle is adjusted to the wet and

dry season The dry season is a yearly period of low rainfall, especially in the tropics. The weather in the tropics is dominated by the tropical rain belt, which moves from the northern to the southern tropics and back over the course of the year. The t ...

in the tropics and subtropics. The eggs are deposited in early summer and measure 5-6 millimetres. For oviposition the female drills a cylinder-shaped duct up to 90 millimetres into the moist soil. The clutch is deposited at the bottom of the duct and contains up to 150 eggs. The duct is then plugged with a frothy substance to keep the eggs moist during the dry season. The initial 5 millimetres long

nymphs A nymph (; ; sometimes spelled nymphe) is a minor female nature deity in ancient Greek folklore. Distinct from other Greek goddesses, nymphs are generally regarded as personifications of nature; they are typically tied to a specific place, land ...

hatch and leave the duct with the first heavy rainfall. During the next three months they go through seven instar stages. In late summer and autumn the last moulting to become

imago In biology, the imago (Latin for "image") is the last stage an insect attains during its metamorphosis, its process of growth and development; it is also called the ''imaginal'' stage ("imaginal" being "imago" in adjective form), the stage in wh ...

s takes place. The last instar stage resembles the imago in shape and appearance but is flightless.

Systematics

The species ''Valanga irregularis'' was first described by the British entomologist Francis Walker in 1870. The

type specimen In biology, a type is a particular wikt:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to ancho ...

is still present in the collection of the

Natural History Museum A natural history museum or museum of natural history is a scientific institution with natural history scientific collection, collections that include current and historical records of animals, plants, Fungus, fungi, ecosystems, geology, paleo ...

London London is the Capital city, capital and List of urban areas in the United Kingdom, largest city of both England and the United Kingdom, with a population of in . London metropolitan area, Its wider metropolitan area is the largest in Wester ...

. The species name comes from the Javanese word "Walang" for "grasshopper". The Latin

byname An epithet (, ), also a byname, is a descriptive term (word or phrase) commonly accompanying or occurring in place of the name of a real or fictitious person, place, or thing. It is usually literally descriptive, as in Alfred the Great, Suleima ...

"irregularis" means "irregular" and indicates the diversity of colour within this species. There are two known subspecies: * ''Valanga irregularis irregularis'' (Walker, 1870) * ''Valanga irregularis signata'' (Sjöstedt, 1921)

Description

Distribution

Ecology

Development

Systematics

References

Further reading