Found in Africa, the Middle East, and Asia, this species inhabits an area of about six million square miles, or 30 countries, during a quiet period. During a plague, when large swarms descend upon a region, however, these locusts can spread out across some 60 countries and cover a fifth of Earth's land surface.
Desert locust plagues threaten the economic livelihood of a tenth of humans. A desert locust swarm can be square miles in size and pack between 40 and 80 million locusts into less than half a square mile.
Each locust can eat its weight in plants each day, so a swarm of such size would eat million pounds of plants every day. To put it into context, a swarm the size of Paris can eat the same amount of food in one day as half the population of France. But experts can look at past weather patterns and historical records to identify the areas where swarms might occur and spray those areas with chemicals.
Some experts worry that locust plagues will worsen in a warming world. Rising sea temperatures are causing prolonged bouts of wet weather, including a surge of rare cyclones in eastern Africa and the Arabian Peninsula where desert locusts thrive. All rights reserved. Common Name: Locusts. Scientific Name: Acrididae. Type: Invertebrates. Diet: Herbivore. Group Name: Swarm. Average Life Span: Several months.
Size: 0. Weight: 0. Size relative to a paper clip:. This photo was submitted to Your Shot, our photo community on Instagram. Follow us on Instagram at natgeoyourshot or visit us at natgeo. Share Tweet Email. The locusts at this level have fully pledged wings and can fly without problem.
They tend to swarm together in areas with plenty of green feed and are destructive in gardens. They move in large swarms and migrate to new fields on exhaustion of current feeds.
They have a lifespan of at most eight weeks during which they reproduce and die. Kendal Elizabeth has been a professional writer and editor since She has specialized in writing pet-related topics, home decor and gardening. Her work has appeared on several online and offline publication.
By using the site, you agree to the uses of cookies and other technology as outlined in our Policy, and to our Terms of Use. Eggs Female locusts lay eggs in suitable locations shortly after mating -- moist sand soils -- according to Australian Ministry of Agriculture.
Nymph The eggs hatch within 10 to 20 days depending on temperature and moisture conditions. Fledglings Due to the softness of their wings, the final molts of the nymphs are not able to fly, according to Real Science. When the hopper sheds its old skin it has a new, soft skin underneath.
This stretches for a short time, allowing the hopper to grow, before it hardens. Moulting usually occurs five times during the development of the Desert Locust apart from the skin-shedding that occurs at hatching. The hopper stage of the life cycle is thus divided into five instars. Hoppers are sometimes called nymphs and the hopper instars are then called nymphal instars. The word 'stage' is occasionally used instead of 'instar' in locust reports, e. Figures show the distinctions between the different instars of the Desert Locust.
The first instar is whitish in colour when newly hatched but in h turns mainly black. As it grows bigger and becomes ready for moulting a pale colour pattern becomes more obvious. It is not always easy to distinguish the second instar from the first but with experience one recognises that the pale colour pattern is more obvious and that the head is much larger. It is easily distinguished from the third instar because there is no sign yet of wing growth. The third instar is easily recognised by the two pairs of wing 'buds' which can be seen projecting from underneath the pronotum on each side of the thorax.
The colour now is conspicuously black and yellow, more black in cold conditions and less black in hot. The wing buds are larger and more obvious but they are still shorter than the length of the pronotum measured along the middle line. The colour of the fifth instar is bright yellow with a black pattern, again varying with temperature.
Wing buds are now longer than the pronotum, but still cannot be used for flight. The final moult is from the fifth-instar hopper to the adult stage. This change is called fledging and the young adult is called a fledgling. After this there is no further moulting and the adult locust cannot grow in size but gradually increases in weight. Notice the thin bent wings hanging down; later they will be pumped full of blood and take up their final shape.
The fledgling is pink and the wings, head and body are relatively soft. Activity is limited to walking and short descending flights. Fledglings gradually become hard and able to fly strongly.
Locusts in this condition are called immature adults. The length of life of individual adults varies. Some have been kept alive in cages for over a year, but in the field they probably live between 2.
Apart from accidental death the life span depends on how long they take to become sexually mature. The quicker they mature the shorter the total length of life. Desert Locusts can exist as scattered individuals within the recession area or, when numerous, as swarms throughout the invasion area.
This is because the locust exists in different phases. When breeding conditions lead to an increase in the numbers of locusts crowded together the insects have the ability to change their colour, behaviour, shape and physiology.
Not all these characteristics change at once; behaviour and colour being the characteristics to change first. An adult in the solitary phase is likely to be pale grey or beige when immature, with the males becoming pale yellow on maturation.
In contrast, an adult from the swarming gregarious phase will be bright pink when immature and bright yellow when mature. Solitary locusts live separately, the hoppers do not move together and the adults usually fly individually at night. They are often difficult to see and their colours blend with their surroundings.
Gregarious hoppers move in marching bands and have distinctive black markings. The brightly coloured adults move together in cohesive day-flying swarms. In between the two extremes are locusts exhibiting some characteristics of solitary locusts and some gregarious ones; such locusts are referred to as transient locusts. Scientists have tried to describe the changes in shape which occur by measuring parts of the locust Fig. For example, if the length of the front wing or elytron E is divided by the length of the femur F of the hind leg the resulting ratio is greater in the case of locusts taken from a swarm than for those locusts living alone.
These measurements are called morphometrics. Changes in the shape of the pronotum and sternum of the Desert Locust are shown in Fig. Unfortunately it is necessary to introduce a note of warning at this point.
Morphometric studies do not always give a completely reliable indication of the behaviour phase. One reason is that changes in behaviour and appearance do not always occur at the same rate. In the Desert Locust for example, some swarms comprise locusts whose morphometrics are the same as those of solitary-living ones. The environmental conditions during the development of the hopper can affect the morphometrics of the adults. Nevertheless, it is safe to state, as a general rule, that locusts taken from swarms will have a certain appearance and certain morphometrics , whilst those of the same species taken from an area where there have been no swarms for several months will have a different appearance and different morphometrics.
Solitary locusts lay pods containing eggs each.
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