Omocestus viridulus
Encyclopedia
Omocestus viridulus is a grasshopper
of the Acrididae
family.
and O. haemorrhoidalis. The eyes of this species may be either brown or yellow. The typical body length is 17–20 mm (0.669291338582677–0.78740157480315 ). They possess a strongly darkened region of the hind wing.
, and it is distributed widely over Britain. Its range extends east as far as Siberia
and Mongolia
. Their preferred habitat consists of areas with longer grass.
, Agrostis
, Anthoxanthum
, Lolium and Holcus
. The life cycle
begins with the females laying their clutch of eggs in the top layer of soil or near the root of the grass stalks. The young are called nymphs and emerge the next April. These nymphs resemble miniature versions of the adults with immature wings. After about a month of moulting their exoskeleton several times, they mature into adults with working wings. There is one generation of O. viridulus a year, and they are usually seen between the months of April and October.
in which the hind leg and wing are rubbed together. Calling songs are used by these grasshoppers in order to attract and find a mate. Although most of the singing is done by the males, females that are ready to mate may also sing in response. The females also use stridulation to produce their songs. The male normally sings only one calling song in one place before moving on to another spot to try calling again. However, occasionally they may call more than once in the same spot. Ticking is another sound that is produced when the male flicks the hind part of its back leg against one of its fore wings (the process is called a tibial flick). In the courtship process, the frequency of these tibial flicks does not follow a regular pattern and is highly variable between 5 and 15 ticks repeated roughly every 1 to 2 seconds. Geographical variation is also present in the mating song of this species. In Spain, where this grasshopper exists as the subspecies O. viridulus kaesteneri, the song tends to be shorter than in other regions. When singing to a female, one of the hind legs is moved at a much wider angle than the other and this generates most of the sound. The songs are characterised by crescendos that make up a significant part of the song. The songs start quietly and increase until it reaches the greatest intensity, and then dies out. The males usually follow up their calling songs with a succession of loud syllables and then try to mate with the female. When the male is calling to a female, there is a greater amplitude of movement for the hind leg facing the female. Males call when a female is close by, and these songs last about 45–60 seconds each with breaks of 10–15 s in between. Various studies have been performed on the songs of O. viridulus. Heinrich et al. demonstrated that singing in both males and females can be induced with the injection of acetylcholine. A study by Eiríksson revealed that the males of this species can use their songs most efficiently based on how frequently they sing and how they time their songs, as it is important that the males minimize the overlap of their songs with the females' song so that they can find each other. If the female sings at the same time as the male, the male might not hear the female's song. The males try to minimize this overlap in songs because he must be able to hear the female’s song in order to locate her.
Grasshopper
The grasshopper is an insect of the suborder Caelifera in the order Orthoptera. To distinguish it from bush crickets or katydids, it is sometimes referred to as the short-horned grasshopper...
of the Acrididae
Acrididae
The 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 are of the Acrididae. The subfamily Oedipodinae is sometimes classified as a distinct family Oedipodidae in the...
family.
Morphology
O. viridulus tend to be green all over, but some may have brown coloration on the sides. In Scandinavia, they tend to have either a green or light brown colour. The males do not have any red coloring on the abdomen and possess a noticeably long ovipositor, characteristics that help distinguish it from the similar species O. rufipesOmocestus rufipes
Omocestus rufipes, the 'Woodland Grasshopper', is a species of 'short-horned grasshoppers' belonging to the family Acrididae subfamily Gomphocerinae....
and O. haemorrhoidalis. The eyes of this species may be either brown or yellow. The typical body length is 17–20 mm (0.669291338582677–0.78740157480315 ). They possess a strongly darkened region of the hind wing.
Distribution and habitat
O. viridulus typically lives in moderately wet regions around Europe except north of the Arctic CircleArctic Circle
The Arctic Circle is one of the five major circles of latitude that mark maps of the Earth. For Epoch 2011, it is the parallel of latitude that runs north of the Equator....
, and it is distributed widely over Britain. Its range extends east as far as Siberia
Siberia
Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...
and Mongolia
Mongolia
Mongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...
. Their preferred habitat consists of areas with longer grass.
Diet and life cycle
This species prefers to feed on the more common, abundant grass species and this may promote greater diversity of vegetation. O. viridulus feeds on grass from the genera DactylisDactylis
Dactylis is a genus of grasses in the subfamily Pooideae, native to Europe, Asia, and northern Africa. They are known in English as cock's-foot or cocksfoot grasses, also sometimes as orchard grasses.-Taxonomy:...
, Agrostis
Agrostis
Agrostis is a genus of over 100 species belonging to the grass family Poaceae, commonly referred to as the bent grasses...
, Anthoxanthum
Anthoxanthum
Anthoxanthum, the vernal grasses or vernalgrasses, is a large genus of true grass with a cosmopolitan distribution.A. odoratum is a common species of acidic grassland and bogs in northern Europe....
, Lolium and Holcus
Holcus
Holcus is a genus of eight species of grasses, native to Europe, Atlantic Ocean islands, Africa and western Asia....
. The life cycle
Biological life cycle
A life cycle is a period involving all different generations of a species succeeding each other through means of reproduction, whether through asexual reproduction or sexual reproduction...
begins with the females laying their clutch of eggs in the top layer of soil or near the root of the grass stalks. The young are called nymphs and emerge the next April. These nymphs resemble miniature versions of the adults with immature wings. After about a month of moulting their exoskeleton several times, they mature into adults with working wings. There is one generation of O. viridulus a year, and they are usually seen between the months of April and October.
Reproduction
Compared to other grasshopper species, the reproductive fitness of O. viridulus tends to be less affected by temperature changes. It has been found that for female O. viridulus, the number of eggs in each pod, and the mass of eggs were not adversely affected by temperature. In the wild, the males find the females quickly and mate, and the females refrain from singing until they lay at least one cluster of eggs. If the male fails to mate with a female, he will sing before trying again.Song
Songs are produced by a process called stridulationStridulation
Stridulation is the act of producing sound by rubbing together certain body parts. This behavior is mostly associated with insects, but other animals are known to do this as well, such as a number of species of fishes, snakes and spiders...
in which the hind leg and wing are rubbed together. Calling songs are used by these grasshoppers in order to attract and find a mate. Although most of the singing is done by the males, females that are ready to mate may also sing in response. The females also use stridulation to produce their songs. The male normally sings only one calling song in one place before moving on to another spot to try calling again. However, occasionally they may call more than once in the same spot. Ticking is another sound that is produced when the male flicks the hind part of its back leg against one of its fore wings (the process is called a tibial flick). In the courtship process, the frequency of these tibial flicks does not follow a regular pattern and is highly variable between 5 and 15 ticks repeated roughly every 1 to 2 seconds. Geographical variation is also present in the mating song of this species. In Spain, where this grasshopper exists as the subspecies O. viridulus kaesteneri, the song tends to be shorter than in other regions. When singing to a female, one of the hind legs is moved at a much wider angle than the other and this generates most of the sound. The songs are characterised by crescendos that make up a significant part of the song. The songs start quietly and increase until it reaches the greatest intensity, and then dies out. The males usually follow up their calling songs with a succession of loud syllables and then try to mate with the female. When the male is calling to a female, there is a greater amplitude of movement for the hind leg facing the female. Males call when a female is close by, and these songs last about 45–60 seconds each with breaks of 10–15 s in between. Various studies have been performed on the songs of O. viridulus. Heinrich et al. demonstrated that singing in both males and females can be induced with the injection of acetylcholine. A study by Eiríksson revealed that the males of this species can use their songs most efficiently based on how frequently they sing and how they time their songs, as it is important that the males minimize the overlap of their songs with the females' song so that they can find each other. If the female sings at the same time as the male, the male might not hear the female's song. The males try to minimize this overlap in songs because he must be able to hear the female’s song in order to locate her.