scholarly journals The Cost and Benefice of Multiple Mating in Desert Locust Schistocerca gregaria

2021 ◽  
Vol 4 (3) ◽  
pp. 49-54
Author(s):  
 Dushimirimana Severin
Keyword(s):  
Schistocerca Gregaria ◽  
Multiple Mating ◽  
Desert Locust ◽  
The Cost

A comparison of nutritional regulation in solitarious- and gregarious-phase nymphs of the desert locust Schistocerca gregaria

2002 ◽  
Vol 205 (1) ◽  
pp. 121-129 ◽  
Author(s):  
S. J. Simpson ◽  
D. Raubenheimer ◽  
S. T. Behmer ◽  
A. Whitworth ◽  
G. A. Wright
Keyword(s):  
Schistocerca Gregaria ◽  
Desert Locust ◽  
Nutritional Regulation ◽  
Body Protein ◽  
Genetic Potential ◽  
Trade Offs ◽  
Nutrient Utilisation ◽  
Two Phases ◽  
Unbalanced Diet ◽  
The Cost

SUMMARY Nutritional regulatory responses were compared for the cryptic ‘solitarious’ and the conspicuously coloured, aggregating ‘gregarious’ phases of the desert locust Schistocerca gregaria. The desert locust has the genetic potential to exist in either phase, changing between them within a lifetime and epigenetically across generations. Our aim was to compare final-instar nymphs of the two phases with respect to key nutritional variables, including (i) points of regulated intake (the ‘intake target’) for protein and carbohydrate, (ii) the nature of trade-offs between over-eating nutrients in excess and under-eating those in deficit when fed nutritionally unbalanced foods, (iii) diet-related patterns of nutrient utilisation, and (iv) the performance consequences of eating nutritionally unbalanced diets. When provided with pairs of nutritionally unbalanced but complementary foods, both phases regulated their intake of protein and carbohydrate to a similar point. However, when confined to foods that were of unbalanced protein to carbohydrate ratio, gregarious nymphs ate more than solitarious insects. Both phases regulated protein growth, but gregarious insects did so to a lower adult body protein content and converted ingested protein to growth less efficiently. When fed a food high in carbohydrate and low in protein, gregarious nymphs deposited more body lipid and survived less well than did solitarious insects. Solitarious nymphs developed more quickly than gregarious nymphs except on the two most extremely unbalanced diets, on which development time was similar. The results are discussed with respect to the different nutritional ecologies of the two phases and used to develop the hypothesis that animals have evolved to trade-off the cost of eating excess of a nutritionally unbalanced diet against the probability of encountering foods of complementary composition in the future.

Field Tests of Dry Baiting against the Desert Locust, Schistocerca gregaria (Forsk.)

1952 ◽  
Vol 42 (4) ◽  
pp. 675-690 ◽  
Author(s):  
D. L. Gunn
Keyword(s):  
Schistocerca Gregaria ◽  
Field Tests ◽  
Field Trials ◽  
Peanut Flour ◽  
Desert Locust ◽  
Complete Destruction ◽  
Marching Bands ◽  
Benzene Hexachloride ◽  
The Cost ◽  
Mammalian Toxicity

Field trials in British Somaliland and in the Anglo-Egyptian Sudan showed that dry bran bait can be used for complete destruction of Desert Locust hoppers (Schistocerca gregaha). Wet bait was never found to be completely effective when dry bait was ineffective.Failures of dry baiting were found which were attributable to several causes : hoppers not feeding just before moulting ; ground too hot for hoppers to remain on it ; too low or too patchy a deposit of bait ; adult locusts probably not making contact with bait. None of these failures could be attributed to the bait being dry.The main constituent of standard bait, wheat bran, should not be replaced by barley husks or peanut flour, but dom flour could be used and dura and maize flours could be tried instead of bran.The use of dry bait makes it convenient and practical for locust scouts who use camels, vehicles, etc. to destroy small bands of hoppers as soon as they find them.Dry baiting against marching bands and ring baiting can be done very conveniently and speedily by means of the Shendi Funnel, designed to be tied to the back of a vehicle.Area baiting can be done rapidly by blowing dry bait up from a dusting machine, so that the wind spreads it. An area-dosage of 25 lb./acre is recommended, and a rate of ½-acre/minute should be readily achieved.The amount of labour required is reduced to about 25% by the use of dry bait instead of wet. Dry baiting by machine uses only 10 per cent. of the labour required for dry-baiting by hand, but the cost would not fall as much as this, because higher wages would have to be paid for the greater skill necessary.Adults can be killed by baiting, but it is much more difficult than with hoppers to ensure that the locusts make contact with the bait.The insecticides already in use against the Desert Locust, arsenic and benzene hexachloride, can completely destroy hoppers when applied in bait. An insecticide is required with a long persistence like that of arsenic and a low mammalian toxicity like that of BHC.

Observations on the effects of γ-radiation on eggs of the desert locust, Schistocerca gregaria (Forsk.)

1966 ◽  
Vol 56 (4) ◽  
pp. 725-735 ◽  
Author(s):  
P. Hunter-Jones ◽  
P. T. Haskell
Keyword(s):  
Schistocerca Gregaria ◽  
Lethal Dose ◽  
Domestic Animal ◽  
Nuclear Radiation ◽  
Desert Locust ◽  
Insecticide Treatment ◽  
Γ Radiation ◽  
Locust Control ◽  
Tissue Recovery ◽  
The Cost

It has been suggested that nuclear radiation might be used for locust control, but insufficient knowledge has hitherto been available to decide whether such a measure is feasible. In this paper, the results of some laboratory experiments on the effect of γ-radiation on eggs of the desert locust, Schistocerca gregaria (Forsk.), are described.After a single dose of γ-radiation, the resulting mortality among the eggs was correlated with the size of the dose received and the age of the egg at the time of irradiation. The dose of radiation required to kill the older eggs was 40 times greater than that required to kill young eggs; thus, a dose of 144 rads caused almost complete inviability among eggs deposited one or two days before irradiation, but a dose in excess of 5,500 rads was required to kill eggs deposited eleven days earlier. For comparison, the lethal dose of γ-radiation for humans is estimated to be 400–700 rad.When the irradiation dose was applied in three small fractions, with intervals between them, the percentage of eggs killed was less than when the same total dose was given in one exposure. This difference was presumably due to tissue recovery during the inter-radiation periods. The temperature to which the eggs were exposed during the inter-radiation periods also affected survival, recovery being greater at higher temperatures.The possibility of using γ-radiation to control locust egg-fields, the cost of the equipment needed and the hazards involved are discussed. It is concluded that control by this method not only offers no advantage in terms of cost, effectiveness or convenience as compared with conventional insecticide treatment but would be very impractical and dangerous to operators and the inhabitants, human and domestic animal, of the treated area. It is possible that other control techniques utilising radiation, such as sterile-male release or attractant traps treated with a sterilant, may be useful against certain species of locusts after further work on the development of chemical attractants has been carried out.

THE HISTOLOGY OF THE GIANT FIBRE SYSTEM IN THE ABDOMINAL VENTRAL NERVE CORD OF THE DESERT LOCUST

1970 ◽  
Vol 102 (9) ◽  
pp. 1163-1168 ◽  
Author(s):  
W. D. Seabrook
Keyword(s):  
Single Cell ◽  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Schistocerca Gregaria ◽  
Desert Locust ◽  
Giant Fibre ◽  
Metathoracic Ganglion ◽  
Giant Fibres ◽  
Giant Fibre System

AbstractSchistocerca gregaria possess four neurones of giant fibre proportions within the abdominal ventral nerve cord. These fibres arise from single cell bodies in the terminal ganglionic mass and pass without interruption to the metathoracic ganglion. Fibres become reduced in diameter when passing through a ganglion. Branching of the giant fibres occurs in abdominal ganglia 6 and 7.

Sign in / Sign up

Export Citation Format

Share Document