Adipokinetic hormone signaling regulates adult dehydration resistance in the migratory locust

Drought events have become more severe under climate change,and this can pose a major threat to the survival of various organisms.The molecular mechanisms involved in dehydration resistance are not well known.Here,adults of the migratory locust,Locusta migratoria,were subjected to food-mediated dehydration,and adipokinetic hormone(AKH)signaling was found to play a key role in regulating dehydration resistance.Specifically,dehydration shortened the lifespan,increased the body weight loss,and reduced the water loss rate in adult locusts.Global transcriptome profiles revealed variations in tissue-specific gene expression between dehydration-resistant locusts and normal locusts.Importantly,dehydration selection and exposure induced prominent expression of AKH genes in the retrocerebral complex of adult locusts.Furthermore,individual knockdown of AKH1,AKH2,or AKH receptor(AKHR)accelerated water loss and shortened the lifespan of adult locusts under dehydration conditions,and trehalose supplementation ameliorated the negative effects caused by interference with AKH or AKHR.These findings demonstrated that AKH/AKHR signaling-dependent trehalose metabolism plays a crucial role in regulating locust dehydration resistance and thus provide novel insights into the regulatory mechanism underlying drought resistance.

Lateral variation in Moho depth around the southern Tanlu fault zone and its adjacent area

We estimated Moho depth beneath the southern Tanlu fault zone and its adjacent area using common-conversion-point(CCP)stacking of receiver functions,which were computed from teleseismic records of the CEArray.Our estimated Moho depth matches well with 2-D profiles derived from active-source deep seismic reflection surveys,suggesting that the calculated the Moho depth map is likely accurate beyond the 2-D profiles.Overall,the estimated Moho depth map showed a high spatial correlation with tectonic provinces,i.e.,Moho topographic boundaries are in good agreement with geological boundaries.Beneath the Dabie orogenic belt and the mountainous areas in southern Anhui Province,the Moho lies relatively deep,and there is an obvious difference in Moho depth between the two sides of this segment of the Tanlu fault.We further selected four depth profiles with dense instrumentation to show Moho depth changes across different tectonic blocks in the study area.We saw two step-like changes in Moho depth beneath the Xiangfan-Guangji and Gushi-Feizhong,which run parallel along the WNW-ESE direction and delineate the southern and northern bounds of the northern Dabie orogenic belt,which is likely the suture zone between the North China Block and South China Block.Crust beneath the northeast corner of the study area is significantly thinner than other areas,which is consistent with the crustal detachment model proposed for suturing between the North and South China blocks in the region east to the Tanlu fault.

A neural m^(6)A pathway regulates behavioral aggregation in migratory locusts

RNA N6-methyladenosine(m^(6)A),as the most abundant modification of messenger RNA,can modulate insect behaviors,but its specific roles in aggregation behaviors remain unexplored.Here,we conducted a comprehensive molecular and physiological characterization of the individual components of the methyltransferase and demethylase in the migratory locust Locusta migratoria.Our results demonstrated that METTL3,METTL14 and ALKBH5 were dominantly expressed in the brain and exhibited remarkable responses to crowding or isolation.The individual knockdown of methyltransferases(i.e.,METTL3 and METTL14)promoted locust movement and conspecific attraction,whereas ALKBH5 knockdown induced a behavioral shift toward the solitary phase.Furthermore,global transcriptome profiles revealed that m^(6)A modification could regulate the orchestration of gene expression to fine tune the behavioral aggregation of locusts.In summary,our in vivo characterization of the m^(6)A functions in migratory locusts clearly demonstrated the crucial roles of the m^(6)A pathway in effectively modulating aggregation behaviors.

Impacts of oxygen deficiency on embryo life-history traits of migratory locust Locusta migratoria from low and high altitudes

Hypoxia challenges aerobic organisms in numerous environments,and hypoxic conditions may become more severe under future climate-change scenarios.The impact of hypoxia on the development of terrestrial insect embryos is not well understood.Here,to address this gap,embryonic life-history traits of migratory locust Locusta migratoria from low-altitude and high-altitude regions were compared under 2 oxygen levels:normoxia(i.e.,21 kPa oxygen partial pressure and mild hypoxia(i.e.,10 kPa oxygen partial pressure).Our results demonstrated that,whether reared under normoxia or mild hypoxia,L.migratoria from high-altitude populations had longer developmental times,reduced weight,and lower mean relative growth rate as compared with those from low-altitude populations.When transferred from normoxia to mild hypoxia,nearly all the tested lifehistory traits presented significant negative changes in the low-altitude populations,but not in the high-altitude populations.The factor'strain'alone explained 18.26%-54.59%of the total variation for traits,suggesting that the phenotypic differences between L.migratoria populations from the 2 altitudes could be driven by genetic variation.Significant genetic correlations were found between life-history traits,and most of these showed differentiation between the 2 altitudinal gradients.G-matrix comparisons showed significant structural differences between L.migratoria from the 2 regions,as well as several negative covariances(i.e.,trade-offs)between traits in the low-altitude populations.Overall,our study provides clear evidence that evolutionary divergence of embryonic traits between L.migratoria populations from different altitudes has occurred.