''Dactylotum bicolor'', also known as the rainbow grasshopper, painted grasshopper, or the barber pole grasshopper, is a species of

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 ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Acrididae The AcrididaeMacLeay WS (1821) ''Horae Entomologicae or Essays on the Annulose Animals'' 2 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 bec ...

. It is native to the United States, Canada and northern Mexico and exhibits

aposematism Aposematism is the advertising by an animal to potential predators that it is not worth attacking or eating. This unprofitability may consist of any defences which make the prey difficult to kill and eat, such as toxicity, venom, foul taste or ...

(warning coloration). It was first described by the German entomologist

Toussaint de Charpentier Toussaint von Charpentier (22 November 1779 – 4 March 1847) was a German geologist and entomologist. He was the author of ''Libellulinae europaeae descriptae e depictae'' (1840). Biography Toussaint von Charpentier was born in Freiberg, Saxony ...

in 1843.

Description

''Dactylotum bicolor'' grows to an average length of about for males and for females. It is mainly black with distinctive reddish and yellowish markings, a pale green

prothorax 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 pale green wingpads. The tibia of the hind leg bears six to eight spines. This species does not develop wings and is unable to fly. Three subspecies are recognised: * ''D. b. bicolor'' – Northern Texas, New Mexico and Mexico * ''D. b. pictum'' – Northern and eastern part of range * ''D. b. variegatum'' – Southern Arizona and western part of range The coloring varies across the insect's range, with ''D. b. pictum'' being black with little red, ''D. b. variegatum'' having distinct red markings, and ''D. b. bicolor'' having a purplish or violet sheen to the background black color. Before the discovery of '' Dichroplus silveiraguidoi'' in Uruguay in 1956, ''Dactylotum bicolor'' had the lowest known number of

chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are ...

s among grasshopper species, with seventeen

acrocentric The centromere links a pair of sister chromatids together during cell division. This constricted region of chromosome connects the sister chromatids, creating a short arm (p) and a long arm (q) on the chromatids. During mitosis, spindle fibers a ...

chromosomes.

Distribution and habitat

It is found in shortgrass prairie, desert grasslands, thinly vegetated areas and alfalfa fields throughout the western

Great Plains The Great Plains (french: Grandes Plaines), sometimes simply "the Plains", is a broad expanse of flatland in North America. It is located west of the Mississippi River and east of the Rocky Mountains, much of it covered in prairie, steppe, an ...

of the United States (and southern Canada), southward to Arizona, New Mexico, Texas, and into northern Mexico.

Biology

Its eggs are laid in soft soil in several batches of about one hundred. These overwinter and hatch in late spring or early summer, with adults being present until September or October. There is a single generation each year. Although adult rainbow grasshoppers are

polyphagous Feeding is the process by which organisms, typically animals, obtain food. Terminology often uses either the suffixes -vore, -vory, or -vorous from Latin ''vorare'', meaning "to devour", or -phage, -phagy, or -phagous from Greek φαγε ...

and feed on many species of plant, the nymphs feed entirely on Wright's false willow ('' Baccharis wrightii'') in Arizona and New Mexico. It has been found that the nymphs orient themselves relative to the sun, positioning themselves around the bush so as to

thermoregulate Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature ...

(keep their body temperature within an acceptable range). In the morning and evening they feed near the ground in full sun, but at midday they move to the shady center. At night they roost in upper branches of the bush, but this may primarily be to avoid ground-based predators. The insect's coloration was shown to be

aposematic Aposematism is the advertising by an animal to potential predators that it is not worth attacking or eating. This unprofitability may consist of any defences which make the prey difficult to kill and eat, such as toxicity, venom, foul taste or ...

in an experiment of predation by little striped whiptail lizards. These brightly-colored grasshoppers were less attractive to the lizards as food than cryptically-colored '' Trimerotropis sp'' of similar size, even though the lizards were unfamiliar with the rainbow grasshopper, which was not present in their natural habitat. The lizards may previously have encountered other prey with warning colors such as stink bugs, seed bugs, or velvet ants. The rainbow grasshopper is also distasteful to birds.

References

{{Taxonbar, from=Q13565184 Melanoplinae Orthoptera of North America Insects described in 1843 Aposematic animals Taxa named by Toussaint de Charpentier Monotypic Orthoptera genera