The migratory locust (Locusta migratoria) is the most widespread locust species, and the only species in the genus Locusta. It occurs throughout Africa, Asia, Europe, Australia and New Zealand. While once common in Europe it has now become rare there. The vast geographic area it occupies, which comprises many different ecological zones, has facilitated the evolution of numerous subspecies (although not all experts agree on the validity of some of these subspecies). Locusta migratoria is a polyphenic species, that is, its pigmentation and size vary according to its "phase" (gregarious or solitary form) and its age. When population densities grow high the migratory locust appears in its smaller gregarious form, which is yellow to orange with black spots. In contrast, solitary form adults are brown or green, and tend to match the vegetation around them. Locusta migratoria in large population numbers can be economically devastating, as both larvae and adults eat huge quantities (adults daily eat their weight in food), and adults, as strong fliers, are highly mobile. Populations are monitored carefully to avoid and control plagues. From Wikipedia 2011a; Wikipedia 2011b
sporont of Gregarina garnhami endoparasitises gut lumen of Locusta migratoria
Animal / parasite / endoparasite
cyst of Malamoeba locustae endoparasitises rectum of Locusta migratoria
Animal / parasite / endoparasite
larva of Mermis nigrescens endoparasitises body cavity of Locusta migratoria
Evolution and Systematics
Swarms of locusts avoid collisions with selective motion-detecting neurons.
"Locusts, which can consume their own weight in food each day, have a large neuron called the locust giant movement detector (LGMD) located behind their eyes. The LGMD releases bursts of energy whenever a locust is on a collision course with another locust or a predatory bird...The [European scientist] team found that the LGMD releases more energy when something is coming directly at the locust.
"These spikes of energy, called action potentials, prompt the locusts to take evasive action. The entire process from motion detection to reaction takes about 45 milliseconds—or 45 thousandths of a second."'Locusts, like most insects, can see many more images per second than we do. This means they can react in time to things that are approaching very rapidly and so make their escape before collision,' Rind [Claire Rind, a biologist at the University of Newcastle upon Tyne in England] said.
"And because the insects only detect things that are on a collision course with them, the locusts are ignorant of all other movements. It's a particularly useful trait, as the locusts travel in dense swarms akin to rush hour traffic." (Roach 2004)
Learn more about this functional adaptation.
Ovipositors of locusts drill deep holes by use of two reciprocating rotating elements.
"When females of locust species such as Locusta migratoria, Schistocerca gregaria (Forskal), S.peregrina (Olivier), Anacridium aegyptium and a number of other Acrididae dig oviposition holes, they stretch the intersegmental membranes between abdominal segments IV, V, VI and VII and thus make a hole considerably deeper than could otherwise be achieved. The ovipositor valves provide the force for this extension. The ovipositor is a boring machine which, once set in motion with its prongs against the soil, must automatically bury itself and in doing so it will stretch the easily extended abdomen to its full length, so long as the insect maintains it hold on the ground. The findings of the study provide an insight to the functioning of the locust apparatus, and suggested the possibility to develop an innovative digging system composed by two reciprocating rotating elements." (Courtesy of the Biomimicry Guild)
Learn more about this functional adaptation.
Molecular Biology and Genetics
Barcode data: Locusta migratoria
Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
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Download FASTA File
Statistics of barcoding coverage: Locusta migratoria
Public Records: 282
Specimens with Barcodes: 295
Species With Barcodes: 1
The migratory locust (Locusta migratoria) is the most widespread locust species, and the only species in the genus Locusta. It occurs throughout Africa, Asia, Australia and New Zealand. It used to be common in Europe but has now become rare there. Because of the vast geographic area it occupies, which comprises many different ecological zones, numerous subspecies have been described. However, not all experts agree on the validity of some of these subspecies.
The migratory locust is polyphenic. It transitions between two main phenotypes in response to population density; the solitary phase and the gregarious phase. As the density of the population increases the locust transforms progressively from the solitary phase towards the gregarious phase with intermediate phases:
- Solitaire = solitary phase → transiens congregans (intermediate form) → gregarious phase → transiens dissocians (intermediate form) → solitaire = solitary phase.
Pigmentation and size of the migratory locust vary according to its phase (gregarious or solitary form) and its age. Gregarious larvae have a yellow to orange covering with black spots; solitary larvae are green or brown. The gregarious adult is brownish with yellow, the latter colour becoming more intense and extensive on maturation. The solitary adult is brown with varying extent of green colour depending on the colour of the vegetation. Gregarious adults vary in size between 40 and 60 mm according to the sex; they are smaller than the solitary adults.
Relationship with humans
Locusts are highly mobile, and usually fly with the wind at a speed of about 15 to 20 kilometres per hour (9.3 to 12.4 mph). Swarms can travel 5 to 130 km or more in a day. Locust swarms can vary from less than one square kilometre to several hundred square kilometres with 40 to 80 million individuals per square kilometre. An adult locust can consume its own weight (several grams) in fresh food per day. For every million locusts, one ton of food is eaten.
In Africa, the last serious widespread plague of L. m. migratorioides occurred from 1928 to 1942. Since then, environmental transformations have made the development of swarms from the African migratory locust unlikely. Nevertheless potential outbreaks are constantly monitored as plagues can be devastating. The Malagasy migratory locust (L. m. capito) still regularly swarms (roughly twice every ten years). The desert locust, which is very similar to the African migratory locust, remains a major threat too.
Locust survey and control are primarily the responsibility of the Ministry of Agriculture in locust-affected countries and are operations undertaken by national locust units. The Food and Agriculture Organization (FAO) of the United Nations provides information on the general locust situation to all interested countries and gives warnings and forecasts to those countries in danger of invasion.
Subspecies of Locusta migratoria
L. migratoria is found over a vast geographic area, and its range covers many different ecological zones. Because of this, numerous subspecies have been described; however, not all experts agree on the validity of some of these subspecies.
- L. m. burmana Ramme, 1951
- L. m. capito Saussure, 1884 (Madagascar)
- L. m. cinerascens Fabricius, 1781 (Italy, Spain)
- L. m. manilensis (Meyen, 1835) 1 (eastern Asia)
- L. m. migratoria (Linnaeus, 1758) (West and Central Asia, eastern Europe)
- L. m. migratorioides (Fairmaire & L.J. Reiche, 1849) (mainland Africa and Atlantic islands)
- L. m. tibetensis Chen, Yonglin, 1963
- L. m. danica (Linnaeus, 1767) = L. m. migratoria (Linnaeus, 1758)
- L. m. gallica Remaudičre, 1947 = L. m. migratoria (Linnaeus, 1758)
- L. m. solitaria Carthy, 1955 = L. m. migratoria (Linnaeus, 1758)
Other species called 'locusts'
Other species of Orthoptera that display gregarious and migratory behaviour are called 'locusts'.
- American locust Schistocerca americana
- Australian plague locust Chortoicetes terminifera
- Bombay locust Nomadacris succincta
- Brown locust Locustana pardalina
- Desert locust Schistocerca gregaria
- Egyptian locust Anacridium aegyptium
- Italian locust Calliptamus italicus
- Moroccan locust Dociostaurus maroccanus
- Red locust Nomadacris septemfasciata
- Rocky Mountain locust Melanoplus spretus – extinct
- Sahelian tree locust Anacridium melanorhodon
- Spur-throated locust, Australis procera
- Sudan plague locust Aiolopus simulatrix
The Senegalese grasshopper (Oedaleus senegalensis) also often displays locust-like behaviour in the Sahel region.
- Oonincx, Dennis G. A. B.; van Itterbeeck, Joost; Heetkamp, Marcel J. W.; van den Brand, Henry; van Loon, Joop J. A.; van Huis, Arnold; Hansen, Immo A. (29 December 2010). "An Exploration on Greenhouse Gas and Ammonia Production by Insect Species Suitable for Animal or Human Consumption". PLoS ONE 5 (12): e14445. doi:10.1371/journal.pone.0014445. PMC 3012052. PMID 21206900.
- Barsics, F., 2010. L'alimentation des Populations locales de Madagascar productrices de Vers à Soie. - Univ. de Liège.: 1-84.
- Chapuis, M-P.; Lecoq, M.; Michalakis, Y.; Loiseau, A.; Sword, G. A.; Piry, S.; Estoup, A. (1 August 2008). "Do outbreaks affect genetic population structure? A worldwide survey in a pest plagued by microsatellite null alleles". Molecular Ecology 17 (16): 3640–3653. doi:10.1111/j.1365-294X.2008.03869.x.
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