Valanga irregularis
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| ( Walker, F. , 1870) |
Valanga irregularis ( English "Hedge Grasshopper", "Giant Green Grasshopper" or "Giant Valanga") is a short-antennae insect fromthe grasshopper family (Acrididae) thatis nativeto the tropics and subtropics of Australia . It is the largest species of locust on the continent. The animals mostly live solitary.
features
The sexes are similar in appearance and differ mainly in height. The females can be between 60 and 75 millimeters long, while the male specimens reach a length of 45 to 55 millimeters. This makes Valanga irregularis the largest species of locust in Australia. Some sources even give a maximum length of the animals of 90 millimeters.
The body color and pattern vary greatly. Adults are cream-brown to gray-green in color and often show a light stripe on the top. The pronotum has a slight keel. The wing wings are spotted, the hind wings are dark gray, sometimes colorless or light green. The splints ( tibia ) are colored like the rest of the body and have clearly visible thorns in orange to red color with black tips.
The color of the nymphs is also very variable. Young individuals are green to brown with darker patterns, later yellow, orange and pink spots appear, the wings are also often pink. In profile, the head is held very high and the topline of the body appears concave, especially in the young stages of development. The elongated compound eyes are vertical in profile and have a long thin strip on the underside. The pronotum also has a slight keel, it is darker in the front half than in the back. Compared to nymphs of other species, the hind legs are longer, visibly thinner and show two clearly visible dark spots on the upper side of the rear thighs ( femora ), which are still easily recognizable in adult animals.
Similar to the species Austracris guttulosa , Valanga irregularis has a distinctive, several millimeter long spur between the front legs. Both types have a comparable shape, can reach almost the same size and also have a similar color. On the basis of the leg thorns, which are colored white instead of reddish in the former species, they can be easily distinguished.
Occurrence and habitat
Valanga irregularis is native to the tropical and subtropical regions of Australia. The distribution area extends from the coastal regions of Western Australia over the northern half of the Northern Territory and large parts of Queensland to the north of New South Wales on the continental side of the Great Australian Mountains .
The species prefers a humid climate and is often found in grasslands or forests in spring and autumn, and can also be found in suburban gardens when the weather is appropriate. After heavy rainfall, it can also occur on the edge of desert areas further inland.
Way of life
These locusts eat practically all fleshy parts of plants, especially leaves, flowers and fruit clusters. They prefer nettle leaf ( Acalypha ), hibiscus ( Hibiscus ) and Bauhinia ( Bauhinia ), another source of food are palm trees (Arecaceae). They have powerful mouthparts, with which they eat the parts of the plant from the edge. The feeding phase lasts all night, on hot and rainy days they hide in the branches.
Adult animals can jump very well and defend themselves against attackers, such as fishing horrors (Mantodea) or lynx spiders (Oxyopidae), with the thorns on their hind legs. They are also well camouflaged as their body color corresponds to the plant stems and leaves on which they are located. They are most vulnerable in the morning hours, when they warm up in the sun on the tops of the leaves. Adults and older nymphs are parasitized by flies of the genus Blaesoxipha . The small wasp species Scelio flavicornis parasitizes the laid eggs.
Valanga irregularis mostly lives solitary and does not form swarms . Under favorable circumstances, the species can also occur more frequently and then cause damage. It is said to have sporadically damaged citrus and coffee plantations , but overall the species is not considered an economically significant pest .
Adult animals largely spend the winter months in their hiding places. However, they are not completely inactive and leave these hiding spots from time to time to eat and sunbathe. The mating season begins with the first warm days in the following spring. Most males attract the females with noises, but typically the pairs meet at the food plants. After the eggs are laid, the adults die.
development
One generation is trained per year, the life cycle is adapted to the wet and dry periods in the tropics and subtropics. The eggs are laid in the damp earth in early summer and are five to six millimeters long. To lay eggs, the female drills a cylindrical channel up to 90 millimeters deep into the ground, lays a clutch of up to 150 eggs on the bottom and closes the channel with a foam-like substance. This way, the eggs will stay moist for a long time even during the drying time.
The nymphs, initially around five millimeters long, hatch after the first heavy rain and then leave the canal through its center, where the foam is less dense. They go through seven stages of development within three months and molt to imago in late summer and autumn . In the last stages of development the nymphs look like the adult animals and already have wings, but they are not yet able to fly.
Systematics
The currently recognized species name Valanga irregularis was given by the British entomologist Francis Walker in 1870, who first described the species as part of his work at the Natural History Museum in London . The type specimen is also in the entomological collection there . The generic name is derived from the Javanese word "Valang" for grasshopper; the Latin epithet means "irregular" and indicates the variety of colors of the species. Other names that are no longer valid are Cyrtacanthacris irregularis (Walker, 1870), Acridium maculicollis (Walker, 1870) and Valanga elegans (Uvarov, 1923).
Two subspecies are recognized:
- Valanga irregularis irregularis (Walker, 1870)
- Valanga irregularis signata (Sjöstedt, 1921)
The subspecies V. i. signata has been described from Queensland and has only been observed there so far. The genus Valanga includes over 30 other species, all of which are native to the Southeast Asian and oceanic regions.
swell
Individual evidence
- ↑ a b Giant or Hedge grasshopper: Valanga irregularis. (No longer available online.) Department of Agriculture, Fisheries and Forestry, Australian Government, April 13, 2007, archived from the original on May 18, 2009 ; accessed on April 24, 2009 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Valanga irregularis (Walker). CSIRO Entomology, September 19, 2004, accessed April 24, 2009 .
- ↑ a b Bruno Pinese, Harry Fay and Rod Elder: Giant grasshopper. Department of Employment, Economic Development and Innovation, Queensland Government, January 5, 2012, accessed July 22, 2013 .
- ↑ Megan Connolly: Hopping mad or just madly hopping. (PDF; 560 kB) (No longer available online.) In: Katherine Rural Review, Ed. 254. Department of Business, Industry and Resource Development, Northern Territory Government, January 2004, archived from the original March 19, 2011 ; accessed on May 13, 2009 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ^ Rentz, Lewis, Su and Upton, p. 339
- ↑ a b c Giant Grasshoppers - The largest grasshopper - Valanga irregularis. Brisbane Insects and Spiders, accessed April 24, 2009 .
- ↑ Rentz, p. 192
- ↑ a b c Giant or Hedge grasshopper: Valanga irregularis (nymph). (No longer available online.) Department of Agriculture, Fisheries and Forestry, Australian Government, April 13, 2007, archived from the original on May 18, 2009 ; accessed on April 24, 2009 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ CSIRO, pp. 391
- ↑ a b Grasshoppers and Locusts. Queensland Museum, accessed July 22, 2013 .
- ↑ a b c d Life and Adaptions to Water - Giant grasshopper ( Memento from October 17, 2009 in the Internet Archive )
- ↑ Giant Grasshopper. Australian Insects australian-insects.com, accessed April 24, 2009 .
- ↑ GL Baker, RJ Dysart and RG Pigott: Parasitism of Grasshopper and Locust Eggs (Orthoptera: Acrididae) by Scelio Species (Hymenoptera: Scelionidae) in Southern Australia . In: Australian Journal of Zoology . tape 44 (4) , 1996, pp. 427-443 .
- ↑ SV Rajakulendran, R. Pigott and GL Baker: Biology and phenology of giant grasshopper, Valanga irregularis (Walker) (Orthoptera: Acrididae: Crytacanthacridinae), a pest of citrus, in central western New South Wales . In: Australian Entomologist . tape 20 (3) , 1993, pp. 81-90 .
- ↑ Identification of Locusts. (PDF; 301 kB) (No longer available online.) Department of Employment, Economic Development and Innovation, Queensland Government, 2007, archived from the original on May 19, 2009 ; accessed on April 24, 2009 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ^ Francis Walker : Catalog of the Specimens of Dermaptera Saltatoria in the Collection of the British Museum. Part III . British Museum, London 1870, p. 425-604 .
- ^ Species Valanga irregularis (Walker, 1870). (No longer available online.) Australian Faunal Directory, Department of the Environment, Water, Heritage and the Arts , Australian Government, October 9, 2008, archived from the original May 17, 2009 ; accessed on April 24, 2009 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ^ Valanga irregularis (Walker, F., 1870). Encyclopedia of Life , accessed April 24, 2009 .
- ↑ DC Eades, D. Otte and P. Naskrecki: Specimen list for subspecies Valanga irregularis signata (Sjöstedt, 1921). Orthoptera Species File Online, accessed April 24, 2009 .
- ↑ Valanga. Encyclopedia of Life , accessed April 24, 2009 .
literature
- CSIRO, Division of Entomology: Insects of Australia . Melbourne University Press, 1991, ISBN 0-522-84638-6 .
- David C. Rentz: Grasshopper Country - the Abundant Orthopteroid Insects of Australia . UNSW Press, 1996, ISBN 0-86840-063-7 .
- David C. Rentz, RC Lewis, YN Su and MS Upton: A Guide to Australian Grasshoppers and Locusts . Natural History Publications, Malaysia 2003, ISBN 983-812-074-X .
Web links
- Giant Grasshoppers - The largest grasshopper - Valanga irregularis. Brisbane Insects and Spiders, accessed April 24, 2009 .
- Hedge grasshopper (Valanga irregularis). Australian Wildlife OzAnimals.com, accessed April 24, 2009 .
- Arthur Chapman: Valanga irregularis (Hedge Grasshopper or Giant Locust). Photo stream on Flickr , March 13, 2009, accessed April 24, 2009 .
