The Senegalese grasshopper (Oedaleus senegalensis) is a medium-sized grasshopper species found in the Sahel region of Africa, the Canary Islands, Cape Verde Islands, and West Asia. Although not called a locust in English, this species shows gregarious behaviour and some morphological change (phase polymorphism) on crowding. In many parts of the Sahel, this species may cause greater year-on-year crop damage than better-known locusts, attacking crops such as the pearl millet.
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TerrestrialTerrestrial animals are animals that live predominantly or entirely on land (e.g., cats, ants, snails), as compared with aquatic animals, which liv...
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OviparousOviparous animals are female animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive...
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This grasshopper is essentially graminivore. It consumes a fairly wide variety of grasses, but in the Sahel, it has a preference for cram-cram (Cenchrus biflorus). It generally attacks cereals, especially millet and maize. Adults like to eat the soft unripe grains. Grasses with a high silica content are avoided.
This species generally has three generations per year during the rainy season, but evidence for the occasional fourth generation has been found during years of exceptionally longs rains. A number of adults of the first and second generations migrate north following the Intertropical Convergence Zone. The adults of the third generation follow the zone on their way back to the south. At that time, populations have often greatly increased leading to the southward migration of huge numbers of grasshoppers, often at the time that millet is ripening in the fields. These can then cause serious damage to the crop. Though the aggregation of grasshoppers around points of light at night might give the impression of swarms, Senegalese grasshoppers do not, in fact, form cohesive swarms as locusts do.
Eggs are laid in sandy soil in small packets of about 20–40 eggs called egg pods. Practically all eggs laid by the first and second generations hatch during the same season, usually within two weeks. However, most eggs of the third generation enter into diapause and survive the long dry season as a partly developed embryo. Within two weeks of the first substantive rain (≥10 mm), about 60% of the eggs hatch, with the remaining 40% hatching after subsequent showers. This is an obvious adaptation to the erratic rains in the Sahel. In some years, the first hoppers that emerge perish because of lack of subsequent rain.
