Phase-related morphological changes induced by [His7]-corazonin in two species of locusts, Schistocerca gregaria and Locusta migratoria (Orthoptera: Acrididae)

2004 ◽  
Vol 94 (4) ◽  
pp. 349-357 ◽  
Author(s):  
K. Maeno ◽  
T. Gotoh ◽  
S. Tanaka
Keyword(s):  
Fore Wing ◽  
Morphological Traits ◽  
Schistocerca Gregaria ◽  
Morphological Changes ◽  
Locusta Migratoria ◽  
Hind Femur ◽  
Desert Locust ◽  
Maximum Width ◽  
Phase Polymorphism ◽  
The Third

AbstractThe effects of a neurohormone, [His7]-corazonin, on phase-related morphological traits (F/C and E/F ratios; F = length of the hind femur, C = maximum width of the head; E = length of fore wing) were re-examined in the desert locust, Schistocerca gregaria Forskål. The F/C ratio was significantly different between adults with five and six nymphal instars, respectively, indicating that they need to be analysed separately. Injections of the synthesized peptide (1 nmol) into individually-reared (solitary) nymphs at the second and third instars caused a shift in classical morphometric ratio towards the value typical for crowded (gregarious) individuals in both sexes. The E/F ratio, which is smaller in solitary locusts than in gregarious ones, was also influenced significantly by injections of [His7]-corazonin into individually-reared locusts. The effect of [His7]-corazonin on E/F ratios was shown more clearly when the nymphs were injected at a higher dose (2 nmol) at the beginning of the third instar. Single injections of the peptide into individually-reared nymphs at different instars revealed that the earlier the injection the larger the ‘gregarizing’ effects of the peptide on F/C and E/F ratios. The same tendency was also detected in Locusta migratoria Linnaeus. These results supported the hypothesis that [His7]-corazonin plays an important role in the control of phase polymorphism in locusts.

scholarly journals Effects of water extracts of frass from three locust species and various plants on oviposition and embryonic development in the desert locust, Schistocerca gregaria

2019 ◽  
Vol 28 (2) ◽  
pp. 195-204
Author(s):  
Seiji Tanaka ◽  
Toyomi Kotaki ◽  
Yudai Nishide ◽  
Amel Ben-Hamouda ◽  
Khemais Abdellaoui ◽  
...  
Keyword(s):  
Plant Species ◽  
Schistocerca Gregaria ◽  
Morphological Changes ◽  
Locusta Migratoria ◽  
Water Extract ◽  
Hatching Rate ◽  
Desert Locust ◽  
Leaf Extracts ◽  
Migratory Locust ◽  
Hatching Rates

The water extract of desert locust, Schistocerca gregaria, frass collected in the wild had an oviposition inhibitory (OI) effect when mixed with sand and presented to adults. Likewise, the leaves of six plant species, as well as frass produced by desert locusts fed with these plants, exerted OI effects when compared with the control sand wetted with water alone. In general, frass extracts had a greater OI effect than the extracts of leaves. The OI effect was also observed when adult desert locusts were exposed to extracts of frass produced by two other locusts, the Bombay locust, Nomadacris succincta, and the migratory locust, Locusta migratoria, fed with rescue grass, Bromus catharticus. Among the three species of locust, desert locust and migratory locust frass exerted a greater OI effect than Bombay locust frass. Frass samples extracted with hot and cool water produced similarly high OI effects, indicating that bacterial involvement during extraction is unlikely. Hatching rates of desert locusts were significantly reduced by extracts of all of the above mentioned frass when the extracts were mixed with sand and used to incubate the eggs. In contrast, the lethal effects of leaf extracts on the hatching rates varied depending on the plant species. The embryos became deformed within four days when three-day-old eggs were incubated in sand containing frass extracts from desert locusts fed with rescue grass, whereas no apparent morphological changes were observed when seven-day-old eggs were similarly tested, although their hatching rate was significantly reduced.

scholarly journals Variation and structure of the eyes in the desert locust, Schistocerca gregaria (Forskål)

1947 ◽  
Vol 134 (875) ◽  
pp. 245-272 ◽  
Keyword(s):  
Schistocerca Gregaria ◽  
Postembryonic Development ◽  
Compound Eyes ◽  
Brown Pigment ◽  
Desert Locust ◽  
Direct Sunlight ◽  
The Third ◽  
Third Stage ◽  
Visual Impact ◽  
The One

The compound eyes of the solitaria phase individuals of the desert locust, Schistocerca gregaria (Forskål), are vertically striped with mostly 6 and 7, rarely 5 and 8, dark brown stripes, and a number of cream-coloured interstripes. In phase gregaria the interstripes, which are more or less invaded by brown pigment, are partially or wholely masked, the eye in the latter case presenting an almost uniformly dark brown appearance. The postembryonic development of the striped eyes, is described stage by stage. There is no stripe at the time of hatching. In the 6-striped eye one stripe is developed in the first-stage hopper and, subsequently a stripe is added at each of the five moults. In the 7-striped eye the one-moult-one stripe relationship holds good in most stages, but the extra seventh stripe is produced in two ways: (i) By the addition of two stripes at the second moult (i. e. the third-stage hopper has four stripes instead of three); and (ii) by the interposition of an extra-moult, usually in the third stage and rarely in the fourth, during which a new stripe is added (stripe-positive extra-moult). But extra-moulting does not necessarily lead to the addition of a stripe; stripe-neutral extra-moults are not infrequent. The development of the dorsal spot and the subdorsal streak are described. The mechanism of growth and the homology and nomenclature of the stripes and interstripes are discussed. The structure of the compound eyes and the pigmentary basis of stripe formation are described, and their effects on vision in solitaria and gregaria individuals discussed. Vision is discussed on the basis of ommatidial structure and pigmentation. In gregaria eyes a perfect apposition image is formed, the image being sharply defined. An ‘anti-halation’ device, produced by the post-retinular layer of pigment, is present. The eye is suited for diurnal vision, and strong direct sunlight is not avoided. In solitaria eyes the image is of the apposition type in its mode of formation but of the superposition type in effect; it has been termed a ‘pseudo-superposition’ image, and is more diffuse but brighter than in gregaria eyes. The ‘anti-halation’ device is weak and ineffective. The eye is suited for vision in subdued light and perceives movements rather than sharp images. Solitaria individuals, especially hoppers, avoid strong, direct sunlight. The effects of these differences in vision on the behaviour of gregaria - and solitaria -phase individuals are as follows: the former, owing to mutual visual impact induced by the formation of sharp images, tend to be gregarious; and further, owing to the presence of light-absorbing mechanisms, they do not avoid strong sunlight; the latter, on the other hand, owing to the want or comparative ineffectiveness of the above-mentioned features, neither tend to congregate nor to go out boldly into the bright open.

The Histology and Histochemistry of Development and Resorption in the Terminal Oocytes of the Desert Locust, Schistocerca Gregaria

1963 ◽  
Vol s3-104 (65) ◽  
pp. 57-68
Author(s):  
O. LUSIS
Keyword(s):  
Corpus Luteum ◽  
Schistocerca Gregaria ◽  
The Body ◽  
Active Part ◽  
Desert Locust ◽  
Lipid Bodies ◽  
Follicular Cells ◽  
The Third ◽  
Postovulatory Follicle ◽  
Β Carotene

During vitellogenesis the follicular cells play an active part in the synthesis of yolk. The term ‘corpus luteum’ as applied to the ovary of the locust is invalid and two terms ‘white’ and ‘yellow’ follicle have been introduced to describe the separate identities of the normal and pathological postovulatory follicle. The protein yolk is a proteincarbohydrate compound, presumably a glycoprotein. Three kinds of lipid bodies are present; the first is a phospholipid, the second a combined phospholipid and triglyceride, and the third triglyceride. Lipids are coloured by dissolved β-carotene. Concentration or absorption of the lipids causes the crystallization of carotene and the formation of the pigment body. During resorption the follicular cells act as lecitholytic cells, first breaking down the protein and then the lipid yolk, and finally degenerating themselves. It is suggested that the oocytes have an inherent potential for resorption, the realization of which depends on various factors within the body.

A Note on the Use of Dried Poison Bait against Locusts in the Sudan

1929 ◽  
Vol 20 (1) ◽  
pp. 99-101 ◽  
Author(s):  
Harold H. King
Keyword(s):  
Red Sea ◽  
Rainy Season ◽  
Arid Regions ◽  
Schistocerca Gregaria ◽  
Locusta Migratoria ◽  
Extended Period ◽  
The Other ◽  
Desert Locust ◽  
The Arid Regions ◽  
Species Being

There are in the Sudan three species of migratory locusts : Anacridium moestum melanorhodon, Walk., or the tree locust, Locusta migratoria, L., and Schistocerca gregaria, Forsk., sometimes termed the desert locust. Of these the last-named is the plague locust of the country—the other two species being relatively unimportant—and is the species referred to as the “ locust ” throughout this paper.From 1899 till 1917 swarms of locusts occurred annually, but then followed a period of ten years during which the Sudan suffered no damage from this pest. In 1927 and again in the succeeding year the locust reappeared as a plague, and there is little doubt but that it is to be expected year by year over an extended period and until the cycle either naturally terminates or is artificially brought to an end. The swarms of fliers appear from May onwards and oviposit in July and August when and where in the arid regions sufficient rain has fallen, the resulting generation of adults emigrating in October. A certain amount of breeding takes place during the winter on the Red Sea littoral, where winter rains occur, but this district is relatively small and easily dealt with ; the main problem is how to prevent breeding during the summer rainy season throughout the vast areas of the central and northern Sudan.

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