Desert Locust Schistocerca Gregaria Forskal Research Articles

Variations in Chemical Composition Value of Adults and Nymphs Desert Locust, Schistocerca gregaria Forskal (Orthoptera: Acrididae)

Recently, interest in the benefits of insects for food and feed has increased, while desert locusts are rich in nutrients and can be easily grown sustainably, even though locusts classified as pests that ruin crops. This study aims to investigate the chemical content, nutritional content and amino acid (AA) profile in adults and nymphs of the desert locust Schistocerca gregaria Forskal (Orthoptera: Acrididae), such as crude protein (CP), crude fat (CF), total carbohydrate (TC), crude fiber (CF), ash, gross energy and minerals content. The analysis indicates that the presence of crude protein, crude fat, total carbohydrate, crude fiber, ash, dry matter and moisture content were (56.79 and 65.92%), (28.82 and 15.15%), (2.98 and 4.59%), (7.9 and 7.92%), (3.51 and 6.42%), (42.34 and 32.46%), and (57.66 and 67.54 %), gross energy content was (498.45 and 418.37 kcal), respectively in adults and nymphs. Generally, the results in both adults and nymphs showed that non-essential AA were the dominant ones of AA, followed by essential then semi-essential AA. Minerals represented by P (87.44 and 91.35), K (6732.78 and 7826.96), Ca (33.8 and 50.7) and Mg (13.56 and 18.24) ppm in adults and nymphs, respectively.

Phylogenic and antagonistic characteristics of novel Bacillus cereus isolates against desert locust, Schistocerca gregaria Forskal (Orthoptera: Acrididae)

Thirty bacterial strains were successfully isolated from dead/diseased nymphs of the desert locust Schistocerca gregaria Forskal (Orthoptera: Acrididae) occurred in rearing cages at Locust and Grasshoppers Research Department, Plant Protection Research Institute, Agricultural Research Center, Dokki, Giza, Egypt. Among them, two isolates, DL3 and DL4, showed a high biocidal activity against locust at preliminary bracketing bioassay. Molecular identification of the two bacterial isolates was carried out by sequencing the 16S rRNA gene and nucleotide blast of international GenBank, and the results showed that DL3 isolate was Bacillus cereus (KY630646) and DL4 isolate was Bacillus cereus (KY630647) with a 100% similarity with Bacillus cereus strain SZAN-2 (GU222440) and Bacillus cereus strain KPRR3 (KY556439), respectively. The insecticidal activity of both isolates against locust nymphs using leaf dipping and per os techniques proved that DL4 isolate was more efficient than DL3 and both of them have the potential to be successful biocidal agents to control desert locust.

Synchrony in the hatching of eggs in the desert locust Schistocerca gregaria (Orthoptera: Acrididae): egg condition influences hatching time in the laboratory and under simulated field temperatures

This study examined the time of hatching of the desert locust Schistocerca gregaria Forskal (Orthoptera: Acrididae) in the laboratory to test the effect of eggs within a pod versus individualized eggs. The pod organization of eggs is thought to play a role in controlling hatching time and to facilitate synchronous hatching at constant temperatures. In the present study, we examined the hatching times of eggs in a pod and individualized eggs under 24-h thermocycles and simulated field temperatures. We tested two patterns of thermocycles consisting of a 12-h thermoperiod (35 or 30 °C) and 12-h cryoperiod (low temperature period; 30 or 25 °C), and two patterns of field temperatures observed in a natural habitat, Mauritania, in May and September. The majority of eggs hatched during low temperature periods in all patterns tested. In addition, the variances of hatching times for individualized eggs were significantly greater than for egg pods in which a clear peak of time of hatching was observed. We show that egg condition influences hatching time under thermocycles of constant and fluctuating temperatures in the laboratory, and may play a role in the adaptive time of hatching.

Effects of the Juvenile Hormone Mimic Pyriproxyfen on Egg Development, Embryogenesis, Larval Development, and Metamorphosis in the Desert Locust Schistocerca gregaria (Orthoptera: Acrididae)

The juvenile hormone mimic pyriproxyfen disrupted embryogenesis when applied topically to eggs of the desert locust Schistocerca gregaria Forskal. Eggs treated on days 3-6 were inhibited at various stages of development, depending on dose and age. In particular, 0.001-0.01 mu g blocked development of 3- and 4-d-old eggs at blastokinesis. Treatment of 7- to 11-d-old eggs was ineffective up to 10 mu g. Insects that hatched successfully failed to display any postembryonic defects. Topical application of the mimic to females had a small ovicidal effect. The metamorphic molt was disrupted when the mimic was applied topically to 5th-instar S. gregaria. Insects retained characteristics of the 5th instar and in extreme cases supernumerary 5th instars were formed. Additional defects included essentially normal adults that were malformed and could not fly. Oral doses were considerably less effective. Application to 4th-instar nymphs did not produce supernumerary characteristics in postecdysial insects, though a large proportion of insects showed abnormalities when they reached adult, which in some cases prevented night. Topical application of the mimic to 5th instar affected the length of the instar. The effects depended on dose and day of treatment.