Editing Locust (section)

{{Short description|Grasshopper that has a swarming phase}}
{{About|the insects in the family Acrididae}}
{{Use dmy dates|date=November 2018}}
{{Use British English|date=November 2018}}
{{Good article}}
[[File:Locusta-migratoria-wanderheuschrecke.jpg|thumb|Locusts, such as this [[migratory locust]] (''Locusta migratoria''),  are grasshoppers in a migratory phase of their life.]]
[[File:CSIRO ScienceImage 7007 Plague locusts on the move.jpg|thumb|Millions of [[swarm]]ing [[Australian plague locust]]s on the move]]

'''Locusts''' (derived from the [[Latin]] ''locusta'', locust or lobster<ref>{{OEtymD|locust}}</ref>) are various [[species]] of short-horned [[grasshopper]]s in the family [[Acrididae]] that have a [[Swarm behaviour|swarming]] phase. These insects are usually solitary, but under certain circumstances they become more abundant and change their behaviour and habits, becoming [[sociality|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 subfamilies.

Normally, these grasshoppers are innocuous, their numbers are low, and they do not pose a major economic threat to agriculture. However, under suitable conditions of [[drought]] followed by rapid vegetation growth, [[serotonin]] in their brains triggers dramatic changes: they start to breed abundantly, becoming gregarious and nomadic (loosely described as [[Insect migration|migratory]]) when their populations become dense enough. They form bands of wingless [[nymph (biology)|nymphs]] that later become swarms of winged adults. Both the bands and the swarms move around, rapidly strip fields, and [[pest (organism)|damage crops]]. The adults are powerful fliers; they can travel great distances, consuming most of the green vegetation wherever the swarm settles.

Locusts have formed [[Swarm behaviour|plagues]] since [[prehistory]]. The [[ancient Egypt]]ians carved them on their tombs and the insects are mentioned in the ''[[Iliad]]'', the [[Mahabharata]], the [[Bible]] and [[Quran]]. Swarms have devastated crops and have caused [[famine]]s and human migrations. More recently, changes in [[agriculture|agricultural]] practices and better surveillance of locust breeding grounds have allowed control measures at an early stage. Traditional locust control uses [[insecticide]]s from the ground or air, but newer [[biological control]] methods are proving effective. Swarming behaviour decreased in the 20th century, but despite modern surveillance and control methods, swarms can still form; when suitable weather conditions occur and vigilance lapses, plagues can occur.

Locusts are large insects and convenient for research and classroom study of zoology. They are [[Entomophagy|edible by humans]]. They have been eaten throughout history and are considered a [[delicacy]] in many countries.