The desert locust is one of about a dozen species of grasshoppers known as locusts which, unlike other grasshoppers, are able to change their behaviour in response to population density and to form swarms that can migrate over large distances. Locust swarms vary from less than one square kilometre to several hundred square kilometres. There can be at least 40 million and sometimes as many as 80 million locust adults in each square kilometre of swarm.

Life span
Extremely variable, depending on weather and ecological conditions, but usually about three to five months.

Statistics
Weight: approx 2g

Physical description
Solitary adults are brown whereas gregarious adults are pink (immature) and yellow (mature).

Distribution
During quiet periods (known as recessions) desert locusts are usually restricted to a band across Africa south of the Sahara and in to India. This is an area of about 16 million square kilometres, consisting of about 30 countries. During plagues, they may spread over an enormous area of some 29 million square kilometres, extending over or into parts of 60 countries in Africa, Asia, Europe and beyond.

Habitat
Semi-arid and arid deserts that receive less than 200mm of rain annually.

Diet
Like most animals of its size, a locust eats roughly its own weight in food each day, about 2g of plant matter.

Behaviour
Shy, solitarious (non-swarming) adults tend to avoid each other except to mate and fly mainly at night. However, at unpredictable intervals locust plagues occur. When locust populations reach a critical density, they change their behaviour from individual (solitarious) insects to acting as part of a group (gregarious). Gregarious adults (swarms) fly during the day. Swept along by desert winds a swarm can advance four metres every second.

Reproduction
Desert locust females lay eggs in an egg pod in sandy soils, 10-15cm below the surface. A solitary female lays about 100-150 eggs whereas a gregarious female lays usually fewer than 80 eggs in an egg pod. Females can lay at least three times in their lifetime usually at intervals of about 6-11 days. Up to 1,000 egg pods have been found in one square metre. The life cycle comprises three stages: egg, hopper and adult. Eggs hatch in about two weeks (the range is 10-65 days). Hoppers develop in stages over 30-40 days. Adults mature in about three weeks to nine months but more frequently from two to four months.

Conservation status
During plagues, locusts can cover more than 20% of the total land surface of the world, where they have the potential to damage the livelihood of a tenth of the world's population.