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Locust

Locust is a common name for certain short-horned grasshoppers in the family Acrididae that can enter a gregarious, swarming phase.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 26, 2026|2 min read| Fact-checked

Locust is a common name for certain short-horned grasshoppers in the family Acrididae that can enter a gregarious, swarming phase. In this phase, individuals change behaviour and sometimes appearance, and large swarms can migrate long distances and damage crops and vegetation. The term does not denote a separate taxonomic group.

Definition

Locust refers to certain acridid grasshoppers that can form dense swarms. The name is used for species with a swarming phase rather than for a separate biological group.

Phases and behaviour

Many locust species show solitary and gregarious phases. When crowding and favourable conditions trigger the change, individuals may alter colour, behaviour, and movement patterns, leading to banding and swarming. The phenomenon has evolved independently in multiple locust lineages.

Ecological and agricultural impact

Locust swarms can travel great distances and consume large amounts of vegetation. This makes them major pests in agriculture and a cause of crop losses in affected regions.

Classification and terminology

Locusts belong to the order Orthoptera and family Acrididae. In some regions, common usage of the term overlaps with grasshopper, but scientifically it is tied to swarm-forming behaviour.

Key facts

  • Locusts are grasshoppers in the family Acrididae that can become gregarious and swarm.
  • The term describes a behavioural phase, not a distinct species or taxon.
  • Swarming locusts can migrate long distances and heavily damage crops.
  • Locusts typically shift from a solitary phase to a gregarious phase under high population density.
  • The phenomenon has evolved independently in multiple locust lineages.
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Canadian context

Locusts are mainly relevant to Canadian readers through agricultural biology, invasive pest studies, and global food-security coverage rather than as a common native pest group.

Frequently asked questions

What is a locust?
A locust is a short-horned grasshopper in the family Acrididae that can shift into a gregarious, swarming phase.
Are locusts a separate species?
No. “Locust” is a behavioural description used for certain grasshopper species, not a separate taxonomic group.
Why do locusts swarm?
Swarming is associated with crowding and other favourable environmental conditions, which can trigger a shift from solitary to gregarious behaviour.
Do locust swarms damage crops?
Yes. Large swarms can strip vegetation and cause severe agricultural damage.
What family do locusts belong to?
Locusts belong to the family Acrididae within the order Orthoptera.
Are all grasshoppers locusts?
No. Only some grasshopper species are called locusts when they have the ability to form swarms.

References

  1. Wikipedia — https://en.wikipedia.org/wiki/Locust
    Supports: Definition as swarming short-horned grasshoppers in Acrididae; no separate taxon; independent evolution of swarming lineages.
  2. Encyclopaedia Britannica — https://www.britannica.com/animal/locust-insect
    Supports: Worldwide distribution; destructive long-distance swarms; general classification in Acrididae.
  3. Encyclopedia.com — https://www.encyclopedia.com/plants-and-animals/animals/zoology-invertebrates/locust
    Supports: Density-related solitary and gregarious phases; swarming and vegetation damage.
  4. Food and Agriculture Organization of the United Nations — https://www.fao.org/locusts-cca/bioecology/what-are-locusts/en/
    Supports: Locusts as short-horned insects in Acrididae and Orthoptera.
  5. Britannica Dictionary — https://www.britannica.com/dictionary/locust
    Supports: Definition as a type of grasshopper that travels in very large groups and can cause destruction by eating crops.