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This article aimed to investigate the challenges that Ethiopia faces during COVID-19. The article looks highly at COVID-19, political instability, desert locust and the ideal conflict between Ethiopia and Egypt on the great Ethiopian renaissance dam. Economic rescission, food insecurity and internal war are also the main topics clearly discussed. The results revealed that unemployment, inflation and income inequality are aggravated as pandemics arise. Thousands were killed and others were displaced due to internal political instability. Output reduction and famine resulted due to desert locust infestation. Bad political spirit is also one fact in Ethiopia due to ideal conflict with Egypt. Consequently, thousands have been arrested; killing innocent people, food insecurity, economic depression and displacement were highly aggravated. While other countries have been moving to prosperity, the Ethiopian economy has been challenged with stagnation. Therefore, the authors suggest that there should be strong intervention from both non-governmental organisation and the government of Ethiopia. Let Ethiopia's recovery come to tell new development. [ABSTRACT FROM AUTHOR]

Insect cuticle can reach a wide range of material properties, which is thought to be the result of adaptations to applied mechanical stresses. Biomechanical mechanisms behind these property variations remain largely unknown. To fill this gap, here we performed a comprehensive study by simultaneous investigation of the microstructure, sclerotization and the elasticity modulus of the specialized cuticle of the femora of desert locusts. We hypothesized that, considering their different roles in jumping, the femora of fore-, mid- and hind legs should be equipped with cuticles that have different mechanical properties. Surprisingly, our results showed that the hind femur, which typically bears higher stresses, has a lower elasticity modulus than the fore and mid femora in the longitudinal direction. This is likely due to the lower sclerotization and different microstructure of the hind femur cuticle. This allows for some deformability in the femur wall and is likely to reduce the risk of mechanical failure. In contrast to both other femora, the hind femur is also equipped with a set of sclerotized ridges that are likely to provide it with the required stiffness to withstand the mechanical loads during walking and jumping. This paper is one of only a few comprehensive studies on insect cuticle, which advances the current understanding of the relationship between the structure, material property and function in this complex biological composite. Insect cuticle is a biological composite with strong anisotropy and wide ranges of material properties. Using an example of the femoral cuticle of desert locusts, we measured the elasticity modulus, microstructure and sclerotization level of the cuticle. Our results show that, although the hind femur withstands most of the stress during locomotion, it has a lower elasticity modulus than the fore and mid femora. This is likely to be a functional adaption to jumping, in order to allow small deformations of the femur wall and reduce the risk of material failure. Our results deepen the current understanding of the structure-material-function relationship in the complex insect cuticle. [Display omitted] [ABSTRACT FROM AUTHOR]

All terrestrial ectotherms are constrained to some degree by their thermal environment and the extent to which they can behaviorally buffer variable thermal conditions. New biophysical modeling methods (NicheMapR) allow the calculation of the body temperature of thermoregulating animals anywhere in the world from first principles, but require detailed observational data for parameterization and testing. Here we describe the thermoregulatory biology of marching bands of the desert locust, Schistocerca gregaria, in the Sahara Desert of Mauritania where extreme heat and strong diurnal fluctuations are a major constraint on activity and physiological processes. Using a thermal infrared camera in the field, we showed that gregarious nymphs altered the microhabitats they used, as well as postural thermoregulatory behaviors, to maintain relatively high body temperature (nearly 40°C). Field and laboratory experiments demonstrated that the preferred body temperature accelerated digestive rates. Migratory bands frequently left foraging sites with full guts before consuming all vegetation and moved to another habitat before emptying their foregut. Thus, the repertoire for behavioral thermoregulation in the desert locust strongly facilitates foraging and digestion rates, which may accelerate developmental rates and increase survival. We used our data to successfully parameterize a general biophysical model of thermoregulatory behavior that could capture hourly body temperature and activity at our remote site using globally available environmental forcing data. This modeling approach provides a stronger basis for forecasting thermal constraints on locust outbreaks under current and future climates. [ABSTRACT FROM AUTHOR]

A striking characteristic of insect cuticle is the wide range of its material property values, with respect to stiffness, strength and toughness. The elastic modulus of cuticle, for instance, ranges over seven orders of magnitude in different structures and different species. Previous studies suggested that this characteristic is influenced by the microstructure and sclerotization of cuticle. However, the relative role of the two factors in determining the material properties of cuticle is unknown. Here we used a combination of scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM) and nanoindentation, to investigate the effect of microstructure and sclerotization on the elastic modulus of tibiae of desert locusts. Our results showed that tibial cuticle is an anisotropic material with the highest elastic modulus along the tibial axis. This is likely because majority of the fibers in the cuticle are oriented along this axis. We also found that the hind tibia has a significantly higher elastic modulus, compared with the fore and mid tibiae. This is likely due to the higher sclerotization level of the hind tibia cuticle, and seems to be an adaptation to the locust locomotion by jumping, in which axial loads in the hind tibiae may reach several times the insect body weight. Our results suggest that while sclerotization determines the difference between the elastic moduli of the tibiae, anisotropic properties of each tibia is controlled by the specific fiber orientation. Our study provides one of only a few comprehensive investigations on insect cuticle, and helps to better understand the structure-material-function relationship in this complex biological composite. Insect cuticle is a biological composite with strong anisotropy and wide ranges of material properties. Using an example of the tibial cuticle of desert locusts, we examined the role of two influential factors on the elastic modulus of cuticle: microstructure and sclerotization. Our results suggested the strong influence of sclerotization on the variation of the elastic modulus among fore, mid and hind tibiae, and that of the microstructure on the anisotropy of each tibia. Our results deepens the current understanding of the structure-material-function relationship in complex insect cuticle. Image, graphical abstract [ABSTRACT FROM AUTHOR]

In this present work, we studied the influence of individual density on the larval moulting rate of three larval stages (third, fourth, fifth instar) in two locust species Schistocerca gregaria and Dociostaurus maroccanus. The moulting position, their duration and the mortality during the moult were also noted. The results show that regrouping individuals accelerates their moult rate. Thus the individuals prefer to realise their moults in vertical position considering the short duration and the survival of larvae during moulting is higher. In contrast the moults performed in horizontal position took a longer duration and increased the mortality rate in all instars examined. [ABSTRACT FROM AUTHOR]

Understanding Desert Locust population dynamics is a prerequisite for the implementation of a preventive management strategy against its invasions. The present study aims to describe these dynamics through conducting probability analyses of locust presence in time and space. Historical data from field surveys conducted by management teams in Mauritania and Morocco for the period 1988–2015 were used. Temporal smoothing and spatio-temporal extrapolations were performed on a monthly basis. We established monthly probability maps of locust observation following two scenarios: recession period (mainly solitarious phase) and invasion period (mainly gregarious phase). Also, observation probability maps of hoppers or mature adults allowed the identification of seasonal breeding areas. The methodology highlights the potentially favourable areas to be monitored every year. It also highlights the lack of information in some areas of the two countries. We observed that the seasonal survey process during recession periods follow the seasonal pattern of gregarious invasions. We argue that this is the result of climatic conditions related to the oscillation of the intertropical convergence zone. However, we advise that these similar yearly cycles should not hinder surveys in recession periods to be conducted in places not receiving swarms during invasion periods. Nevertheless, we conclude that these maps should be helpful for planning the preparation of survey teams in the field. This will reduce survey operation costs and decrease invasion risks. [ABSTRACT FROM AUTHOR]

Copyright of Biotechnologie, Agronomie, Societe et Environnement is the property of Les Presses Agronomiques de Gembloux and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Highlights: [•] The French colonial Empire was in crisis during WWII. [•] Efforts to control Desert Locusts helped resolve this crisis. [•] Responses to locust invasions enabled new modes of government. [•] Resulting field allowed transnational federation of techno-scientific benevolence. [•] Fit or mismatch between institutions and ecological dynamics is unstable, contingent. [Copyright &y& Elsevier]

Abstract: Newly ecdysed 5th instar Schistocerca gregaria nymphs were orally treated with LC75 of the chitin synthesis inhibitor teflubenzuron (135ppm) for 24h; subsequently they were offered an untreated diet for the duration of this instar. Ultrastructural observation of the cuticle in 7 day old untreated 5th instar desert locust nymphs showed that the moulting events had already began. Meanwhile, in treated nymphs of the same age, the ultrastructure of the integument showed that the moulting process was delayed, as no new chitin lamellae of 5th instar were formed and lamellae of the previous instar were still evident. Furthermore, a protein matrix was observed as a homogenous layer with the lack of chitin and occurrence of vacuoles and abundance of mitochondria. The cuticle dry weight in treated 8day old nymphs was significantly less than that of the control, (i.e. 8.5 and 15mg/nymph, respectively). Furthermore, in 8day old treated 5th instar nymphs, chitin and total soluble protein content were 4.5 and 4.85mg/ nymph, respectively. These weights were also highly significantly less than their equivalent control being 8.5 and 7.85mg/nymph for chitin and total soluble protein, respectively. Inhibition in chitin and protein synthesis was calculated to be 88.9% and 61.85%, respectively, in 8day old 5th instar nymphs following their treatment with LC75 concentration of teflubenzuron. [Copyright &y& Elsevier]

Using autocorrelation analysis and autoregressive integrated moving average (ARIMA) modelling, we analysed a time series of the monthly number of 1° grid squares infested with desert locust Schistocerca gregaria swarms throughout the geographical range of the species from 1930-1987. Statistically significant first- and higher-order autocorrelations were found in the series. Although endogenous components captured much of the variance, adding rainfall data improved endogenous ARIMA models and resulted in more realistic forecasts. Using a square-root transformation for the locust data improved the fit. The models were only partially successful when accounting for the dramatic changes in abundance which may occur during locust upsurges and declines, in some cases successfully predicting these phenomena but underestimating their severity. Better fitting models were also produced when rainfall data were added to models of an equivalent series for desert locust hoppers (nymphs) that incorporated lagged data for locust swarms as independent variables, representing parent generations. The results are discussed in relation to predicting likely changes in desert locust dynamics with reference to potential effects of climate change. [ABSTRACT FROM AUTHOR]

This study evaluates how in-utero exposure to an insect pest invasion, particularly, the outbreak of desert locust swarms, affects early childhood health in Africa and Asia over the past three decades (1990–2018). Employing the difference-in-differences model, we find that children being prenatally exposed to the outbreak have their height-for-age, weight-for-height, and weight-for-age z-scores lower by 0.159, 0.148, and 0.155 standard deviations, respectively, compared to unexposed children. Our heterogeneity analyses show that the health setbacks disproportionately fall on children of disadvantaged backgrounds, i.e., those born to lower-educated mothers, poorer mothers, and rural mothers. To the extent that poor health in early life exerts long-lasting irreversible consequences over the life cycle, the study calls for effective measures to minimize the pernicious effects of the desert locust swarm outbreak. • We evaluate the impacts of in-utero exposure to desert locust swarms on child health. • Exposed children have height-for-age z-scores lower by 0.159 standard deviations. • The reduction in weight-for-height z-scores is 0.148 standard deviations. • Weight-for-age z-score declines by 0.155 standard deviations. • Children of disadvantaged backgrounds are especially vulnerable. [ABSTRACT FROM AUTHOR]

Abstract: The original locust control strategy assumed that plagues arose when swarms escaped from outbreak areas and bred successfully in the surrounding invasion area. Thus, control within outbreak areas could prevent plagues. Plague prevention was achieved for species with small, relatively accessible outbreak areas providing resources allocated to preventive control allowed continuous monitoring and rapid treatment as outbreaks appeared. Plague prevention was less successful for species such as the Australian Plague Locust and the Desert Locust in which pre-plague bands and swarms develop and migrate within very large geographical areas. The success of preventive control can be demonstrated, however, by comparing population size and distribution before and after the strategy was implemented using effective control techniques. Some but not all recent plagues of the Australian Plague Locust have been prevented and, although the frequency of Desert Locust plagues has not declined in the last 40 years, their duration and extent has been sufficiently reduced to achieve the original objective of keeping major agricultural zones in the invasion area locust free. In Australia, substantial resources and the latest technology were available to implement early intervention and its success has been clearly demonstrated. We used a simple model to quantify the case for early intervention in Desert Locust campaigns and our simulations suggest that applying even a conservative rate of control from the beginning of an upsurge as part of early intervention would further reduce the size of upsurges and plagues and would contribute to a better managed Desert Locust population. [Copyright &y& Elsevier]

The desert locust represents a serious threat to food security in many African, Middle Eastern, and Southwest Asian countries. Desert locust breeding, maturation, and diffusion are strongly influenced by local environmental parameters, mainly rainfall, temperature, wind, and related features such as soil humidity and vegetation development. The recurring simultaneous occurrence of outbreaks and seasonal breeding over wide regions suggests the existence of large-scale forcing due to climatic anomalies. Even if the connections between climate anomalies and desert locust upsurges have been hypothesized in the literature, no inference has been demonstrated for large-scale climatic processes, allowing their potential use as predictors. In the present study we assessed a historical data series on desert locust population dynamics by integrating several data sources. A climatic analysis was carried out on a monthly basis covering the period 1979-2005 using the global NCEP-DOE Reanalysis dataset. The Wilcoxon non-parametric test was used to establish whether identified West African atmospheric patterns in upsurge years present significant differences compared to recession years. The analysis suggests a significant role of a weaker easterly flow at the core of the African Easterly Jet during spring, coupled with stronger westerly moisture advection. These climatic features may indeed explain meteorological conditions supporting many contemporaneous outbreaks, eventually developing into an upsurge (i.e. widespread rainfall events over key areas). [ABSTRACT FROM AUTHOR]

Abstract: Morphological features of the eugregarine Gregarina garnhami (Canning, 1956) parasitic in the caeca and mid-gut of the desert locust, Schistocerca gregaria, have been studied by transmission and scanning electron microscopy, with particular attention to the epimerite and the relationship between the epimerite and the host epithelium. The cytoplasmic core of the globular epimerite is overlain by a distinct cortical zone, limited on its cytoplasmic face by a membrane-like structure, with an underlying layer of mitochondria. The periphery of the cortical zone is strengthened by a mass of fine filaments, especially at its base. Fine tubular structures, apparently arising from the membrane-like structure, pass through the cortical zone and attach to the epimerite–host cell interface. The base of the cortical zone is supported by a distinct osmiophilic ring. The epimerite is separated from the rest of the gregarine body by a discontinuous septum. Maturing and mature trophozoites possess conically arranged fibrils, which arise from the epimeritic septum and continue into the protomerite region. The epimerite and associated structures are here discussed with regard to the detachment of the trophozoite from the host epithelium. In individuals already detached from the host epithelium, a central depression remained at the top of their protomerite, in the area formerly bearing the epimerite. [Copyright &y& Elsevier]

Copyright of VertigO is the property of La Revue Electronique en Sciences de l'Environnement VertigO and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Most Desert Locust control is carried out on bands of nymphs using aerial sprays. Ultra low volume control from the air demands a large target block containing a number of bands. A computer model has been developed to mimic search to find and mark control blocks either by vehicle and or by aircraft with various band distributions. The operator can choose values of some relevant variables. In a series of simulations proposed vehicle search methods proved to be either ineffective, or to require unrealistic assumptions or excessive resources in the simulation. Only aerial target detection and demarcation produced a satisfactory result. That is in accord with field experience for the Australian Plague Locust. [Copyright &y& Elsevier]