Locusts undergo incomplete or direct metamorphosis. Unlike in insects such butterflies or moths, there is no pupal stage.
There are three main stages of development - egg, nymph and adult. The nymph or hopper stage can be further divided into growth stages called instars, with a moult between each. The following diagram shows the life cycle of the Australian plague locust which has five instar stages. The times given for development are under optimum conditions during summer and are only approximate.
Locust eggs are laid in the soil. The female drills a hole into the ground using the ovipositor at the tip of the abdomen and lays a 'pod' of eggs which is sealed with froth. The froth helps to protect the eggs from desiccation, disease and predation.
Exposed locust egg pod with white froth plug at soil surface.
The curved shape is typical of shallow autumn laid egg pods
After completing each instar the locust nymph sheds, or moults, its skin to continue to grow. On hatching the nymph is wingless but with each successive moult the developing wing buds increase in size and these can be used to determine the growth stages of nymphs.
The final moult into the adult stage is known as fledging, when the locust develops fully formed flying wings. The young adults of most species take a few weeks to become sexually mature.
Green vegetation is necessary for nymphal and adult survival, adult migration and egg development. Synchronised egg laying usually follows rainfall.
How long it takes for a locust to reach maturity depends on the species, habitat conditions and temperature. Nymphs and adults are able regulate their body temperature by basking in the sun or moving to shade.
Further details are available on the life cycle of the economically important species, the Australian plague locust, spur-throated locust and migratory locust.