Locusts are various species of short-horned grasshoppers in the family Acrididae that have a swarming phase. These insects are usually solitary, but under certain circumstances they become more abundant and change their behaviour and habits, becoming gregarious. No taxonomic distinction is made between locust and grasshopper species; the basis for the definition is whether a species forms swarms under intermittently suitable conditions; this has evolved independently in multiple lineages, comprising at least 18 genera in 5 different acridid subfamilies.
The Rocky Mountain locust is an extinct species of grasshopper that ranged through the western half of the United States and some western portions of Canada with large numbers seen until the end of the 19th century. Sightings often placed their swarms in numbers far larger than any other locust species, with one famous sighting in 1875 estimated at 198,000 square miles (510,000 km2) in size, weighing 27.5 million tons and consisting of some 12.5 trillion insects, the greatest concentration of animals ever speculatively guessed, according to Guinness World Records.
The Australian Plague Locust Commission (APLC) is a joint venture of the Australian Government and the member states of New South Wales, Victoria, South Australia and Queensland, created in 1974 to manage outbreaks of the Australian plague locust, spur-throated locust and migratory locust in eastern Australia. With 19 staff members at its headquarters in Canberra and field offices in Narromine, Broken Hill and Longreach, it is jointly funded by the Commonwealth government and by the Australian states of New South Wales, Victoria, South Australia and Queensland.
The desert locust is a species of locust, a periodically swarming, short-horned grasshopper in the family Acrididae. They are found primarily in the deserts and dry areas of northern and eastern Africa, Arabia, and southwest Asia. During population surge years, they may extend north into parts of Southern Europe, south into Eastern Africa, and east in northern India. The desert locust shows periodic changes in its body form and can change in response to environmental conditions, over several generations, from a solitary, shorter-winged, highly fecund, non-migratory form to a gregarious, long-winged, and migratory phase in which they may travel long distances into new areas. In some years, they may thus form locust plagues, invading new areas, where they may consume all vegetation including crops, and at other times, they may live unnoticed in small numbers.
The migratory locust is the most widespread locust species, and the only species in the genus Locusta. It occurs throughout Africa, Asia, Australia and New Zealand. It used to be common in Europe but has now become rare there. Because of the vast geographic area it occupies, which comprises many different ecological zones, numerous subspecies have been described. However, not all experts agree on the validity of some of these subspecies.
The Mormon cricket is a large insect native to western North America in rangelands dominated by sagebrush and forbs. Anabrus is a genus in the shield-backed katydid subfamily in the Tettigoniidae family, commonly called katydids, bush crickets, and previously "long-horned grasshoppers". Its common name, "Mormon cricket", is a misnomer: true crickets are of the family Gryllidae.
The silverleaf whitefly is one of several species of whitefly that are currently important agricultural pests. A review in 2011 concluded that the silverleaf whitefly is actually a species complex containing at least 40 morphologically indistinguishable species.
The red locust is a large grasshopper species found in sub-Saharan Africa. Its name refers to the colour of its hind wings. It is sometimes called the criquet nomade in French, due to its nomadic movements in the dry season. When it forms swarms, it is described as a locust.
The African armyworm, also called okalombo, kommandowurm, or nutgrass armyworm, is a species of moth of the family Noctuidae. The larvae often exhibit marching behavior when traveling to feeding sites, leading to the common name "armyworm". The caterpillars exhibit density-dependent polyphenism where larvae raised in isolation are green, while those raised in groups are black. These phases are termed solitaria and gregaria, respectively. Gregaria caterpillars are considered very deleterious pests, capable of destroying entire crops in a matter of weeks. The larvae feed on all types of grasses, early stages of cereal crops, sugarcane, and occasionally on coconut. The solitaria caterpillars are less active and undergo much slower development. The species is commonly found in Africa, but can also be seen in Yemen, some Pacific islands, and parts of Australia. African armyworm outbreaks tend to be devastating for farmland and pasture in these areas, with the highest-density outbreaks occurring during the rainy season after periods of prolonged drought. During the long dry seasons ("off-season"), the population densities are very low and no outbreaks are seen.
Choristoneura fumiferana, the eastern spruce budworm, is a species of moth of the family Tortricidae native to the eastern United States and Canada. The caterpillars feed on the needles of spruce and fir trees. Eastern spruce budworm populations can experience significant oscillations, with large outbreaks sometimes resulting in wide scale tree mortality. The first recorded outbreaks of the spruce budworm in the United States occurred in about 1807, and since 1909 there have been waves of budworm outbreaks throughout the eastern United States and Canada. In Canada, the major outbreaks occurred in periods circa 1910–20, c. 1940–50, and c. 1970–80, each of which impacted millions of hectares of forest. Longer-term tree-ring studies suggest that spruce budworm outbreaks have been recurring approximately every three decades since the 16th century, and paleoecological studies suggest the spruce budworm has been breaking out in eastern North America for thousands of years.
The Senegalese grasshopper is a medium-sized grasshopper species found in the Sahel region of Africa, the Canary Islands, Cape Verde Islands, and West Asia. Although not called a locust in English, this species shows gregarious behaviour and some morphological change on crowding. In many parts of the Sahel, this species may cause greater year-on-year crop damage than better-known locusts, attacking crops such as the pearl millet.
Gastrimargus musicus, the yellow-winged locust or yellow-winged grasshopper, is a common grasshopper in Australia. It only displays its yellow back wings in flight, when it also emits a loud clicking sound. When swarming, the adults become dark brown. They are sometimes confused with the Australian plague locust, though the yellow winged locust is "stouter and larger".
Dociostaurus maroccanus, commonly known as the Moroccan locust, is a grasshopper in the insect family Acrididae. It is found in northern Africa, southern and eastern Europe and western Asia. It lives a solitary existence but in some years its numbers increase sharply, and it becomes gregarious and congregates to form swarms which can cause devastation in agricultural areas. The species was first described by Carl Peter Thunberg in 1815.
In 2012, Madagascar had an upsurge in the size of its Malagasy migratory locust populations. In November of that year, the government issued a locust alert, saying that conditions were right for swarming of the pest insects. In February 2013, Cyclone Haruna struck the country, creating optimal conditions for locust breeding. By late March 2013, approximately 50% of the country was infested by swarms of locusts, with each swarm consisting of more than one billion insects. The authorities changed the situation to plague status. According to one eyewitness: "You don't see anything except locusts. You turn around, there are locusts everywhere".
Schistocerca americana is a species of grasshopper in the family Acrididae known commonly as the American grasshopper and American bird grasshopper. It is native to North America, where it occurs in the eastern United States, Mexico, and the Bahamas. Occasional, localized outbreaks of this grasshopper occur, and it is often referred to as a locust, though it lacks the true swarming form of its congener, the desert locust.
Patanga succincta, the Bombay locust, is a species of locust found in India and southeast Asia. Usually a solitary insect, only in India has it has exhibited swarming behaviour. The last plague of this locust was in that country between 1901 and 1908 and there have not been any swarms since 1927. It is thought that the behaviour of the insects has altered because of changing practices in agricultural land use.
Locusta migratoria manilensis, commonly known as the Oriental migratory locust, is a subspecies of the migratory locust in the family Acrididae. It is sufficiently different in size and structure from the African migratory locust to be considered a distinct subspecies of the migratory locust. It is found in southeastern Asia and is an important agricultural pest in the region. It is normally a solitary insect but when conditions are suitable, it enters into a gregarious phase when the young form into bands which move together and the adults into swarms. Although outbreaks may have recently been fewer in number and size because of changes in agricultural practices and better locust detection, the insects remain active as crop pests and the potential for outbreaks is still present.
Locusta migratoria migratorioides, commonly known as the African migratory locust, is a subspecies of the migratory locust family Acrididae.
In January 2016, Argentina faced the largest locust swarm for over 60 years. Diego Quiroga, Argentina's agriculture agency’s chief of vegetative protection, said that it was impossible to eradicate the swarm, so they focused on minimizing the damage caused by it by sending out fumigators equipped with backpack sprayers to exterminate small pockets of young locusts that are still unable to fly. This method of extermination, however, is unable to wipe out pocket of locusts hidden in Argentina's large, dry forests. The swarm covered an area the size of 1,900 square miles (5,000 km2) in Northern Argentina. The locusts were expected to grow ten inches (25 cm) and mature into flying swarms by 5 February.
Between June 2019 and February 2022, a major outbreak of desert locusts began developing, threatening food supplies in East Africa, the Arabian Peninsula and the Indian subcontinent. The outbreak was the worst to hit Kenya in 70 years, and the worst in 25 years for Ethiopia, Somalia, and India.
