Seasonal movements of swarms of Locusta migratoria migratorioides (R. & F.) in western Africa in 1928 to 1931

1967 ◽  
Vol 57 (3) ◽  
pp. 357-380 ◽  
Author(s):  
Anne Batten
Keyword(s):  
Sierra Leone ◽  
Locusta Migratoria ◽  
Gulf Of Guinea ◽  
The South ◽  
Locusta Migratoria Migratorioides ◽  
Western Africa ◽  
Surface Front ◽  
Westerly Winds ◽  
Westward Movement ◽  
Time Of Year

Cartographical analysis of the distribution of recorded swarming populations of Locusta migratoria migratorioides (R. & F.) in western Africa for the first four years of the 1928–41 plague of this species has shown seasonal latitudinal displacements in each year with a nroth-to-northweastward movement of swarms during the monthe February-March to August-September, and a south-to-south-westward return during the priod October until the end of the year or January or Ferbruary of the following year.Changes in the position of the northern limit of distribution of swatms in western Africa from month during 1931 have indicated a probable relationship between its position and that of the Intertropical Front, in its seasonal displacement, the position of the surface front being inferred from that of the 10-mm. isohyet. From February to September 1931, following the northward displacement of the Intertropical Front and the northward penetration of south-westerly winds, a general northward displacement of swarms occurred. Similarly, following the southward advance of northerly winds, there was a southward displacement of swarms.There was an eastward movement in the main latitudinal displacement. This was particularly marked in 1929 and 1930. By September 1929, the infestation that in April had been restricted to parts of south-western Guinea and norther Sierra Leone had spread north-eastwards to cover the greater part of the Voltaic Republic and southern Mali; from December 1929 to January-February 1930, following the south-westward movement from late September to November 1929 which confined swarms to the countries bordering the Atlantic and the Gulf of Guinea. there was a spread eastwards along the coastal areas from south-eastern Ghana to southern and eastern Nigeria; and following the main northward movement of swarms which began in western AFrica in April 1930, there was, from May-June onwards, a pronounced eastward migration to the central and eastern parts of the continent. Each of these eastward movements occurred in areas where, at that particular time of year, the prevailing winds would be from the south-west.The deduced movements suggest that swarms of Locusta in western Africa move downwind, and that the principal seasonal changes in the distribution of swarms in that area occur in response to the latitudinal displacement of the Intertropical Front and its associated wind field.

Rapid fish stock depletion in previously unexploited seamounts: the case ofBeryx splendensfrom the Sierra Leone Rise (Gulf of Guinea)

2015 ◽  
Vol 37 (3) ◽  
pp. 405-409 ◽  
Author(s):  
F Salmerón ◽  
JC Báez ◽  
D Macías ◽  
L Fernandez-Peralta ◽  
A Ramos
Keyword(s):  
Sierra Leone ◽  
Fish Stock ◽  
Gulf Of Guinea ◽  
Stock Depletion

South Atlantic Creole Archipelagos

2021 ◽  
Keyword(s):  
Sierra Leone ◽  
19Th Century ◽  
21St Century ◽  
16Th Century ◽  
Gulf Of Guinea ◽  
Early 21St Century ◽  
Cabo Verde ◽  
Plantation Economy ◽  
Sao Tome And Principe ◽  
African Slaves

In 2020 Cabo Verde (1557 sq. miles) and São Tomé and Príncipe (621 sq. miles) had a resident population of 556,857 and 210,240 respectively. Both archipelagos were uninhabited when they were settled by Portuguese colonists and African slaves in the second half of the 15th century. The coexistence of Europeans and Africans resulted in the emergence of Creole societies. Due to their differences in geographic position and climate, they developed unequally in economic terms. Santiago, the first of the Cabo Verde Islands to be settled, became a commercial hub for the slave trade from the Upper Guinea coast. São Tomé was also engaged in the slave trade, but in the 16th century established the first tropical plantation economy based on sugar and slave labor. In the 17th century, both archipelagos were affected by economic and demographic decline. Economic recovery did not occur before the mid-19th century. The British established a coal supply station for transatlantic steam shipping in São Vicente, while, enabled by the introduction of coffee and cocoa, the Portuguese reestablished the plantation economy in São Tomé and Príncipe. After the abolition of slavery in 1875 the workforce was composed of contract workers from Angola, Cabo Verde, and Mozambique. As a result, São Tomé and Príncipe became marked by immigration for almost a century. In contrast, pushed by famines and misery, a massive emigration from Cabo Verde began in the 19th century, a feature that has marked the archipelago’s society and identity until the early 21st century. The first anticolonial groups in exile appeared in the late 1950s. An armed liberation struggle in the islands was not possible; however, a group of Cabo Verdeans participated in the armed struggle in Portuguese Guinea. Most prominent among them was Amílcar Cabral (b. 1924–d. 1973). After independence in 1975 the two countries became socialist one-party regimes. In 1990 both archipelagos introduced multiparty democracies with semipresidential regimes. Creole communities also developed in the Gulf of Guinea islands of Bioko (779 square miles) and Annobón (6.5 sq. miles), which belonged to Portugal until 1778 when they became part of Spanish Guinea which subsequently, in 1968, gained independence as Equatorial Guinea. In the 16th century the uninhabited island of Annobón was settled by the Portuguese with African slaves. As a result, the island’s early-21st-century 5,300 inhabitants speak a Portuguese-based Creole, Fá d’Ambó. Bioko (Fernando Po), was the only Gulf of Guinea Island with a native population, the Bubi, and therefore the Portuguese never colonized this island. From 1827–1843 the British navy maintained an antislaving station called Port Clarence (modern Malabo) in Fernando Po. The British recruited workers from Freetown in Sierra Leone, which was the beginning of the development of the Fernandinos, a local Creole community that speaks an English-based Creole language known as Pichi, which is closely related to Krio in Sierra Leone. Currently, there are still about thirty Fernandino families, comprising some 350 people; however, Pichi is spoken by an estimated 150,000 people, since it also became Bioko’s lingua franca spoken by the Bubi majority.

scholarly journals SURVIVAL OF MIGRATORY LOCUST AT DIFFERENT KEEPING CONDITIONS

2020 ◽  
Author(s):  
A.B. Gerus ◽  
◽  
Y.S. Tokarev ◽  
G.R. Lednev ◽  
M.B. Levchenko ◽  
...  
Keyword(s):  
Survival Rate ◽  
Locusta Migratoria ◽  
Migratory Locust ◽  
Locusta Migratoria Migratorioides ◽  
Gregarious Locusts

In this article we studied the conditions for keeping two species of gregarious locusts: the African migratory locust (Locusta migratoria migratorioides) and the Asian migratory locust (Locusta migratoria migratoria) in open and shaded areas. Based on the data obtained, it is shown that the survival rate of insects of the non-diapausal subspecies was higher in comparison with the obligate monovoltine.

Some Temperature Responses of Nymphs of Locusta Migratoria Migratorioides (R. & F.), with Special Reference to Aggregation

1955 ◽  
Vol 32 (1) ◽  
pp. 126-139
Author(s):  
R. F. CHAPMAN
Keyword(s):  
Locusta Migratoria ◽  
Group Formation ◽  
Physiological State ◽  
Radiant Heat ◽  
Dynamic State ◽  
Large Cage ◽  
Locusta Migratoria Migratorioides ◽  
Temperature Responses ◽  
Definite Temperature ◽  
Linear Manner

1. The results of experiments in a temperature gradient showed a definite temperature ‘preference’ on the part of hoppers (nymphs) of all stages. This ‘preference’ was constant from instar to instar but varied with the preconditioning temperature. 2. The rate of movement of first-instar hoppers was shown to increase in a linear manner with temperature up to 25° C., above which the rate fell off. It is suggested that these are quantitative data supporting Kennedy's (1939) remarks on negative thermokinesis. 3. Experiments in 12 l. cages showed that group formation depends on a patchy temperature field rather than on any particular temperature, and that environmental conditions are more important than mutual responses of the hoppers. Hoppers less than 3 days old, as well as older ones, formed groups under the conditions of patchy temperature. 4. The experiments suggested that surface temperatures are more important than air or body temperatures in the initial formation of groups. 5. Basking groups induced by local radiant heat in a large cage did not differ in form from the groups in the 12 l. cages formed in the absence of radiant heat. 6. Surface texture was shown to be unimportant in group formation, hoppers always collecting on the hotter surface even when temperature differences were of the order of only 1° C. 7. The groups were shown to be in a very dynamic state, with hoppers continually coming and going. The average time spent in a group by any one hopper was 6 min. 46 sec. 8. Formation of basking groups in the field depends on the physiological state of the hoppers, rather than on any definite temperature.

A Physiological Interpretation of the Marching of Hoppers of the African Migratory Locust (Locusta Migratoria Migratorioides R. & F.)

1954 ◽  
Vol 31 (2) ◽  
pp. 271-279
Author(s):  
PEGGY E. ELLIS ◽  
G. HOYLE
Keyword(s):  
Filter Paper ◽  
Potassium Salt ◽  
Locusta Migratoria ◽  
Sugar Solution ◽  
Migratory Locust ◽  
Low Concentration ◽  
Locusta Migratoria Migratorioides ◽  
Retarding Effect ◽  
Short Period ◽  
Blood Potassium

1. Hoppers of the locust Locusta migratoria migratorioides R. & F., which have been reared crowded, exhibit characteristic marching behaviour in the laboratory in foodless cages under standard conditions. 2. The rate of attainment of maximum marching by a given group of hoppers is greatest following a short period of starvation immediately preceding transfer to these conditions. 3. A meal of filter-paper soaked in sugar solution only, exerts no retarding effect on the rate of attainment of full marching, whilst if an adequate concentration of potassium salt is added in addition a definite retardation is observed. 4. In locusts actively feeding on grass the potassium content of the blood is relatively high, and it is suggested that this causes a reduced muscular efficiency which may explain retardation in attainment of full marching. 5. The marching pattern is the result of the activity of particular nerve centres which require a period of activation by a combination of factors before full expression is achieved. Two final factors are essential for the maintenance of the marching state, a low concentration of blood potassium and mutual stimulation by other marching hoppers.

Guinea

2020 ◽  
Author(s):  
Marius Schneider ◽  
Vanessa Ferguson
Keyword(s):  
West Africa ◽  
Sierra Leone ◽  
Ivory Coast ◽  
Official Language ◽  
The South ◽  
Guinea Bissau ◽  
The North

Guinea, also sometimes referred as Guinea-Conakry, is found in West Africa. It is bordered by Guinea-Bissau, Senegal, and Mali in the north and Sierra Leone, Liberia, and Ivory Coast in the south. In 2016, Guinea had a population of 12.6 million over a territory of 245 860 square kilometres (km). Its capital and largest city is Conakry. The official language of Guinea is French, and the currency used is the Guinean franc (GNF).

Sign in / Sign up

Export Citation Format

Share Document