The seasonal migrations and dynamics of populations of the African Migratory Locust (Locusta migratoria migratorioides Reiche and Fairmaire) in the outbreak area [Orth ]
Introduction. — An important corallary of the phase theory of locust out¬ break (Uvarov, 1921) was the suggestion that the transformation of individuals to the gregarious or swarming phase did no occur throughout the range of the species but only in certain well defined regions. Such regions were described, first as permanent breeding grounds (Uvarov, loc. cit.) later, as reservations (Uvarov, 1932) and are known today as outbreak areas (3rd International Locust Conference). The oubreak area of the African Migratory Locust was defined at the fifth International Locust Conference in 1938 following the earlier surveys of Lean (1936) and Zolotarevsky (1948). The limits included all the flood plains of the river Niger from the barrage at Markala, to Timbuctoo in the north toge¬ ther with a narrow strip of the thorn scrub wich forms the border between the flood plains and the adjacent semi-arid regions. This area was considered to be the only one in which swarm production could take place and, in view of its importance to all neighbouring countries, an international organisation was created to survey and destroy all incipient swarms. The history of this
