The wart-biter (''Decticus verrucivorus'') is a

bush-cricket Insects in the family Tettigoniidae are commonly called katydids (especially in North America), or bush crickets. They have previously been known as "long-horned grasshoppers". More than 8,000 species In biology, a species is the basic un ...

in the family

Tettigoniidae Insects in the family Tettigoniidae are commonly called katydids (especially in North America), or bush crickets. They have previously been known as "long-horned grasshoppers". More than 8,000 species are known. Part of the suborder Ensifera, t ...

. Its

common Common may refer to: Places * Common, a townland in County Tyrone, Northern Ireland * Boston Common, a central public park in Boston, Massachusetts * Cambridge Common, common land area in Cambridge, Massachusetts * Clapham Common, originally com ...

and

scientific Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earliest archeological evidence for ...

names derive from the eighteenth-century Swedish practice of allowing the crickets to nibble at

wart Warts are typically small, rough, hard growths that are similar in color to the rest of the skin. They typically do not result in other symptoms, except when on the bottom of the feet, where they may be painful. While they usually occur on the ...

s to remove them.

Description

Adult wart-biters are , with females being significantly larger than males. They are typically dark green in colour, usually with dark brown blotches on the

pronotum The prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites (exoskeletal plates) are the pronotum (dorsal), the prosternum (ventral), and the propleuron (lateral) on ea ...

and wings (a dark brown

morphotype In biology, polymorphism is the occurrence of two or more clearly different morphs or forms, also referred to as alternative ''phenotypes'', in the population of a species. To be classified as such, morphs must occupy the same habitat at the s ...

also occurs). The female has a long and slightly upcurved

ovipositor The ovipositor is a tube-like organ used by some animals, especially insects, for the laying of eggs. In insects, an ovipositor consists of a maximum of three pairs of appendages. The details and morphology of the ovipositor vary, but typical ...

. The wart-biter has a

song A song is a musical composition intended to be performed by the human voice. This is often done at distinct and fixed pitches (melodies) using patterns of sound and silence. Songs contain various forms, such as those including the repetitio ...

consisting of a rapidly repeated series of short bursts of clicks, sometimes lasting for several minutes. Wart-biters normally move about by walking; they rarely fly, except when frightened. Most can only fly at a time.

Subspecies

The ''Orthoptera Species File''Orthoptera Species File: species ''Decticus verrucivorus'' (Linnaeus, 1758) (Version 5.0/5.0 retrieved 8 February 2021)
/ref> lists: * ''D. verrucivorus assiduus'' Ingrisch, Willemse & Heller, 1992 * ''D. verrucivorus brevipennis'' Götz, 1970 * ''D. verrucivorus crassus'' Götz, 1970 * ''D. verrucivorus gracilis'' Uvarov, 1930 * ''D. verrucivorus latipennis'' Liu, Chen & Liu, 2020 * ''D. verrucivorus longipennis'' Nedelkov, 1907 * ''D. verrucivorus mithati'' Ramme, 1939 * ''D. verrucivorus monspeliensis'' Rambur, 1838 * ''D. verrucivorus sayram'' Liu, Chen & Liu, 2020 * ''D. verrucivorus stoljarovi'' Götz, 1970 * ''D. verrucivorus verrucivorus'' (Linnaeus, 1758) - nominate subspecies, to which the 'wart-biter' belongs.

Habitat

The species is found in

calcareous grassland Calcareous grassland (or alkaline grassland) is an ecosystem associated with thin basic soil, such as that on chalk and limestone downland. Plants on calcareous grassland are typically short and hardy, and include grasses and herbs such as clover ...

and

heathland A heath () is a shrubland habitat found mainly on free-draining infertile, acidic soils and characterised by open, low-growing woody vegetation. Moorland is generally related to high-ground heaths with—especially in Great Britain—a cooler ...

habitats. Wart-biters need a

mosaic A mosaic is a pattern or image made of small regular or irregular pieces of colored stone, glass or ceramic, held in place by plaster/mortar, and covering a surface. Mosaics are often used as floor and wall decoration, and were particularly pop ...

of vegetation, including bare ground/short turf, grass tussocks, and a sward rich in flowering

forb A forb or phorb is an herbaceous flowering plant that is not a graminoid (grass, sedge, or rush). The term is used in biology and in vegetation ecology, especially in relation to grasslands and understory. Typically these are dicots without woo ...

s. They prefer areas that are not heavily grazed. The species is

thermophilous A thermophile is an organism—a type of extremophile—that thrives at relatively high temperatures, between . Many thermophiles are archaea, though they can be bacteria or fungi. Thermophilic eubacteria are suggested to have been among the ear ...

, and tends to occur on sites with a southerly aspect.

Diet

The species is omnivorous. Plants eaten include

knapweed ''Centaurea'' () is a genus of over 700 species of herbaceous thistle-like flowering plants in the family Asteraceae. Members of the genus are found only north of the equator, mostly in the Eastern Hemisphere; the Middle East and surrounding reg ...

, nettles,

bedstraw ''Galium'' is a large genus of annual and perennial herbaceous plants in the family Rubiaceae, occurring in the temperate zones of both the Northern and Southern Hemispheres. Some species are informally known as bedstraw. There are over 600 spe ...

s; the species also eats insects, including other

grasshopper Grasshoppers are a group of insects belonging to the suborder Caelifera. They are among what is possibly the most ancient living group of chewing herbivorous insects, dating back to the early Triassic around 250 million years ago. Grasshopp ...

s. Despite its name, the eponymous warts are not a major part of its diet.

Life cycle

The wart-biter lays its eggs in the soil; these eggs normally hatch after two winters. It then passes through seven

instar An instar (, from the Latin '' īnstar'', "form", "likeness") is a developmental stage of arthropods, such as insects, between each moult (''ecdysis''), until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or ass ...

stages between April and June. The adult stage is reached in the beginning of July. Wart-biter populations peak in late July and early August. Newly hatched Decticus are encased in a sheath to facilitate their trip to the soil surface, the sheath holding the legs and antennae safely against the body while burrowing upwards. A neck which can in turn be inflated and deflated, enlarges the top of its tunnel, easing its passage upwards.

Status and distribution

This species occurs throughout continental

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

, except the extreme south, ranging from southern

Scandinavia Scandinavia; Sámi languages: /. ( ) is a subregion#Europe, subregion in Northern Europe, with strong historical, cultural, and linguistic ties between its constituent peoples. In English usage, ''Scandinavia'' most commonly refers to Denmark, ...

Portugal Portugal, officially the Portuguese Republic ( pt, República Portuguesa, links=yes ), is a country whose mainland is located on the Iberian Peninsula of Southwestern Europe, and whose territory also includes the Atlantic archipelagos of ...

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , i ...

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical re ...

, and

Greece Greece,, or , romanized: ', officially the Hellenic Republic, is a country in Southeast Europe. It is situated on the southern tip of the Balkans, and is located at the crossroads of Europe, Asia, and Africa. Greece shares land borders with ...

. It is also found in temperate

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...

, as far east as

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

. Geographic features such as mountains have fragmented the species, leading to a wide range of forms and numerous

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

. In Britain, the wart-biter is confined to five sites, two in

East Sussex East Sussex is a ceremonial and non-metropolitan county in South East England on the English Channel coast. It is bordered by Kent to the north and east, West Sussex to the west, and Surrey to the north-west. The largest settlement in East Su ...

, and one each in

Wiltshire Wiltshire (; abbreviated Wilts) is a historic and ceremonial county in South West England with an area of . It is landlocked and borders the counties of Dorset to the southwest, Somerset to the west, Hampshire to the southeast, Gloucestershire ...

Essex Essex () is a county in the East of England. One of the home counties, it borders Suffolk and Cambridgeshire to the north, the North Sea to the east, Hertfordshire to the west, Kent across the estuary of the River Thames to the south, and G ...

Dorset Dorset ( ; archaically: Dorsetshire , ) is a county in South West England on the English Channel coast. The ceremonial county comprises the unitary authority areas of Bournemouth, Christchurch and Poole and Dorset (unitary authority), Dors ...

and

Kent Kent is a county in South East England and one of the home counties. It borders Greater London to the north-west, Surrey to the west and East Sussex to the south-west, and Essex to the north across the estuary of the River Thames; it faces ...

Conservation

The population of wart-biters has declined in many areas of northern Europe. In Britain, it is threatened with

extirpation Local extinction, also known as extirpation, refers to a species (or other taxon) of plant or animal that ceases to exist in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinct ...

. The species is the subject of a

United Kingdom Biodiversity Action Plan The United Kingdom Biodiversity Action Plan or (UK BAP) was the UK government's response to the Convention on Biological Diversity, opened for signature at the Rio Earth Summit in 1992. The UK was the first country to produce a national Biodiversi ...

References

External links

Wart-biter page at ARKive
{{Taxonbar, from=Q958048 Tettigoniidae Orthoptera of Europe Insects described in 1758 Taxa named by Carl Linnaeus