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The northern subspecies of desert locust Schistocerca gregaria gregaria has recently expanded into western Asia. It poses a serious threat to food security in areas that are already socially and politically unstable. Its further expansion into other parts of southwestern Asia is an issue of great concern (e.g., China).We assembled S. g. gregaria occurrence records that were accumulated by the Food and Agriculture Organization and environmental variables that summarized aspects of climate, soil condition and vegetation. We predicted the potential distribution of S. g. gregaria via the fine‐tuned Maxent model and ensemble ecological niche model approaches.The models predicted that India and other southwestern Asian countries face high risk of S. g. gregaria invasion because of the presence of suitable habitats and the absence of natural barriers that would prevent S. g. gregaria dispersal into these areas. By contrast, the risk of S. g. gregaria invasion in China is low because the suitability values were very low. Moreover, the Tianshan Mountains, the Kunlun Mountains and the Himalaya Mountains may act as natural barriers against S. g. gregaria dispersal.Responses of S. g. gregaria to these environmental variables were modelled using fine‐tuned Maxent models. [ABSTRACT FROM AUTHOR]

[Display omitted] • In desert locust adults, male accessory glands become fully developed after 9 days. • SgEcR mRNA levels are significantly higher in fat body of sexually mature males. • Knockdown of SgEcR , not SgRXR, increased relative weight of male accessory glands. • Knockdown of SgEcR or SgRXR caused a delay in the onset of mating behavior. • In some cases Sg EcR and Sg RXR might act independently of each other. Locusts have been known as pests of agricultural crops for thousands of years. Recently (2018–2021) the world has faced the largest swarms of desert locusts, Schistocerca gregaria , in decades and food security in large parts of Africa and Asia was under extreme pressure. There is an urgent need for the development of highly specific bio-rational pesticides to combat these pests. However, to do so, fundamental research is needed to better understand the molecular mechanisms behind key physiological processes underpinning swarm formation, such as development and reproduction. The scope of this study is to investigate the possible role(s) of the ecdysteroid receptor in the reproductive physiology of male S. gregaria. Ecdysteroids and juvenile hormones are two important classes of insect hormones and are key regulators of post-embryonic development. Ecdysteroids are best known for their role in moulting and exert their function via a heterodimer consisting of the nuclear receptors ecdysone receptor (EcR) and retinoid-X receptor (RXR). To gain insight into the role of SgEcR and/or SgRXR in the male reproductive physiology of S. gregaria we performed RNAi-induced knockdown experiments. A knockdown of SgEcR , but not SgRXR , resulted in an increased relative weight of the male accessory glands (MAG). Furthermore, the knockdown of these genes, either in combination or separately, caused a significant delay in the onset of mating behavior. Nevertheless, the MAG appeared to mature normally and the fertility of mated males was not affected. The high transcript levels of SgEcR in the fat body, especially towards the end of sexual maturation in both males and females, represent a remarkable finding since as of yet the exact role of SgEcR in this tissue in S. gregaria is unknown. Finally, our data suggest that in some cases SgEcR and SgRXR might act independently of each other. This is supported by the fact that the spatiotemporal expression profiles of SgEcR and SgRXR do not always coincide and that knockdown of SgEcR , but not SgRXR, significantly affected the relative weight of the MAG. [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., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Massive desert locust swarms have been threatening and devouring natural vegetation and agricultural crops in East Africa and West Asia since 2019, and the event developed into a rare and globally concerning locust upsurge in early 2020. The breeding, maturation, concentration and migration of locusts rely on appropriate environmental factors, mainly precipitation, temperature, vegetation coverage and land-surface soil moisture. Remotely sensed images and long-term meteorological observations across the desert locust invasion area were analyzed to explore the complex drivers, vegetation losses and growing trends during the locust upsurge in this study. The results revealed that (1) the intense precipitation events in the Arabian Peninsula during 2018 provided suitable soil moisture and lush vegetation, thus promoting locust breeding, multiplication and gregarization; (2) the regions affected by the heavy rainfall in 2019 shifted from the Arabian Peninsula to West Asia and Northeast Africa, thus driving the vast locust swarms migrating into those regions and causing enormous vegetation loss; (3) the soil moisture and NDVI anomalies corresponded well with the locust swarm movements; and (4) there was a low chance the eastwardly migrating locust swarms would fly into the Indochina Peninsula and Southwest China. [ABSTRACT FROM AUTHOR]

Currently (2020), Africa and Asia are experiencing the worst desert locust (Schistocerca gregaria) plague in decades. Exceptionally high rainfall in different regions caused favorable environmental conditions for very successful reproduction and population growth. To better understand the molecular mechanisms responsible for this remarkable reproductive capacity, as well as to fill existing knowledge gaps regarding the regulation of male reproductive physiology, we investigated the role of methoprene-tolerant (Scg-Met) and Taiman (Scg-Tai), responsible for transducing the juvenile hormone (JH) signal, in adult male locusts. We demonstrated that knockdown of these components by RNA interference strongly inhibits male sexual maturation, severely disrupting reproduction. This was evidenced by the inability to show mating behavior, the absence of a yellow-colored cuticle, the reduction of relative testes weight, and the drastically reduced phenylacetonitrile (PAN) pheromone levels of the treated males. We also observed a reduced relative weight, as well as relative protein content, of the male accessory glands in Scg-Met knockdown locusts. Interestingly, in these animals the size of the corpora allata (CA), the endocrine glands where JH is synthesized, was significantly increased, as well as the transcript level of JH acid methyltransferase (JHAMT), a rate-limiting enzyme in the JH biosynthesis pathway. Moreover, other endocrine pathways appeared to be affected by the knockdown, as evidenced by changes in the expression levels of the insulin-related peptide and two neuroparsins in the fat body. Our results demonstrate that JH signaling pathway components play a crucial role in male reproductive physiology, illustrating their potential as molecular targets for pest control. [ABSTRACT FROM AUTHOR]