Nature's Most Destructive Swarm | 20 Years of Planet Earth | BBC Earth

Scientific concepts, discoveries, and nature phenomena

• Desert locust population “boom-and-bust” triggered by favorable conditions

  • Eggs can remain dormant in the soil for ~20 years.
  • When conditions become favorable, eggs hatch, producing hoppers (young, flightless locusts).

• Locust developmental acceleration under optimal conditions

  • Normally, hopper-to-adult development takes about 4 weeks.
  • When conditions are right (abundant growth/food), development switches to a “fast track.”

• Chemical signaling and group migration

  • Hoppers locate feeding areas by following the smell of sprouting grass.
  • Adult locusts release pheromones (chemical “scent messages”) that signal others to move on when local vegetation is depleted.

• Swarm formation and scale

  • When groups merge, they can form swarms.
  • Swarms can combine into giant plagues:
    • Several billion locusts
    • Up to ~40 miles wide

• Mass feeding and ecological impact

  • An adult locust can eat approximately its own body weight every day.
  • A whole swarm can consume hundreds of tons of vegetation, potentially stripping edible plant material along their path.

• Wind-aided dispersal and movement toward resource-rich areas

  • Swarms travel with the wind as an energy-saving flight strategy.
  • Heading toward low-pressure areas where wind interacts with rain and promotes vegetation growth.

• Transient nature of outbreaks

  • The spectacular plagues are rare at this scale and do not last long once food is depleted, leaving only the desert wind.

Researchers or sources featured

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