Migratory Locust
Locusta migratoria
A traveler transformed by crowding
The migratory locust is one of the most widely distributed grasshoppers. Depending on population density, it takes on two strikingly different forms — solitary and gregarious — in appearance and behavior. At low density it lives alone with dull coloring; once crowded, it turns brightly colored and swarms together.
Key figures
- Length
- About 35–55 mm; the gregarious and solitary forms differ slightly in body proportions
- Generations
- Eggs overwinter in the soil; 2–4 generations occur per year, depending on the region
- Habitat
- Grassland, farmland, and river floodplains — open vegetated environments
- Diet
- Herbivorous, feeding on grasses and crops such as wheat, maize, and rice
- Jumping
- The hind-leg femurs are spring-like and powerful, letting it jump distances of more than ten times its body length
- Migration
- Gregarious individuals are strong sustained fliers; swarms can migrate hundreds of kilometers and cause locust plagues
Life cycle
Egg (overwinters in soil) → Nymph (hopper, 5–6 instars) → Adult
Ecological role
At low density, the migratory locust is an ordinary herbivorous member of grassland ecosystems. Once its population surges and switches to the gregarious form, it consumes large quantities of crops and has historically been one of the main species responsible for locust plagues.
Did you know
The locust’s shift from solitary to swarming gregarious form is not caused by different genes but by crowding itself — repeated touching of its hind legs raises serotonin, changing its color and behavior.
Range
Most of China; widely distributed across temperate and tropical grasslands of Eurasia and Africa
Status
Common; a sharp rise in population density can trigger regional locust plagues, making it an important target for pest control
Anatomy
- Hind legs — The femurs are thick like compressed springs; a single push against the ground can launch it more than ten times its body length
- Wings — In the gregarious form, the wings are longer than the body, supporting sustained flights of hundreds of kilometers
- Hearing organ (tympanum) — Located on both sides of the first abdominal segment, used to pick up sounds produced by other locusts rubbing their wings
- Compound eyes — Large and bulging, highly sensitive to the movement of both fellow locusts and predators
- Antennae — Thread-like; repeated contact with other individuals triggers changes in internal neurotransmitter levels
- Thorax shield (pronotum) — Its shape differs subtly between the gregarious and solitary forms, helping to distinguish the two
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