Pl�omorphisme mitochondrial dans les corpora allata de Locusta migratoria migratorioides (R. et F.) au cours de la vie imaginale

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.

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

Journal of Experimental Biology ◽

10.1242/jeb.32.1.126 ◽

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.

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

Journal of Experimental Biology ◽

10.1242/jeb.31.2.271 ◽

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.

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