Wing Development Research Articles

Military might: a domestic economy explanation of Turkish foreign policy

ABSTRACT Turkish foreign policy has taken a military turn in recent years. Turkey is now a major arms exporter, it hosts military bases in its neighborhood and beyond, and has engaged in conflicts in Syria and Libya. Scholars have highlighted identity and international system theories to explain the military assertiveness in Turkish foreign policy. This study proposes a domestic economy explanation. It argues that national wealth, a take-off in defence industry, and an alliance of conservative bourgeoisie and political Islamists are the primary drivers of the military turn in foreign policy. Analysis of Turkish economic development and historical trajectories of economic and bureaucratic wings of the defence industry shows that complex business-politics interactions and commercial interests of defence companies propel military assertiveness. This domestic economy framework supplements insights from the identity and international system theories to significantly add to our understanding of the military turn in Turkish foreign policy.

Impacts of high temperature during early capped brood on pupal development and the size of appendages in adult workers Apis cerana

Whether the development of honeybee broods is healthy or not determines the productivity of bee colonies. Pupation is a critical period in the development of holometabolous insects, characterized by the transition from larva to pupa, and its sensitivity to high temperature was investigated in Apis cerana worker bees. Mature larvae (ML), the first and second days of prepupa (PP1 and PP2), and the first day of pupa (P1) were exposed to 40°C for varied durations of time. The mortality, development duration, birth weight, size of the body, and appendages of eclosed Apis cerana worker bees were measured. Results showed that PP1 had the highest mortality, the lowest birth weight, and the longest development duration among the pupation stages. When exposed to 40°C for 12 h and 16 h, more than 28 and 84% of PP1 failed to complete development, respectively. Additionally, high-temperature treatment had a significant effect on the length of the proboscis, the size of the forewing, and the size of the hind leg. These findings suggest that ML and PP1 are crucial checkpoints for wing and appendage (proboscis and legs) development and provide insights into the mechanisms of honeybee brood susceptibility to high-temperature stress in the context of global warming.

Endoplasmic Reticulum Calcium Mediates Drosophila Wing Development.

The temporal dynamics of morphogen presentation impacts transcriptional responses and tissue patterning. However, the mechanisms controlling morphogen release are far from clear. We found that inwardly rectifying potassium (Irk) channels regulate endogenous transient increases in intracellular calcium and bone morphogenetic protein (BMP/Dpp) release for Drosophila wing development. Inhibition of Irk channels reduces BMP/Dpp signaling, and ultimately disrupts wing morphology. Ion channels impact development of several tissues and organisms in which BMP signaling is essential. In neurons and pancreatic beta cells, Irk channels modulate membrane potential to affect intracellular Ca++ to control secretion of neurotransmitters and insulin. Based on Irk activity in neurons, we hypothesized that electrical activity controls endoplasmic reticulum (ER) Ca++ release into the cytoplasm to regulate the release of BMP. To test this hypothesis, we reduced expression of four proteins that control ER calcium, Stromal interaction molecule 1 (Stim), Calcium release-activated calcium channel protein 1 (Orai), SarcoEndoplasmic Reticulum Calcium ATPase (SERCA), small conductance calcium-activated potassium channel (SK), and Bestrophin 2 (Best2) using RNAi and documented wing phenotypes. We use live imaging to study calcium and Dpp release within pupal wings and larval wing discs. Additionally, we employed immunohistochemistry to characterize Small Mothers Against Decapentaplegic (SMAD) phosphorylation downstream of the BMP/Dpp pathway following RNAi knockdown. We found that reduced Stim and SERCA function decreases amplitude and frequency of endogenous calcium transients in the wing disc and reduced BMP/Dpp release. Our results suggest control of ER calcium homeostasis is required for BMP/Dpp release, and Drosophila wing development.

Transcriptome profiling for developmental stages Protaetia brevitarsis seulensis with focus on wing development and metamorphosis.

A white-spotted flower chafer Protaetia brevitarsis seulensis widely distributed in Asian countries is traditionally used in oriental medicine. This study explored gene expression abundance with respect to wing development and metamorphosis in P. b. seulensis based on the large-scale RNA-seq data. The transcriptome assembly consists of 23,551 high-quality transcripts which are approximately 96.7% covered. We found 265 wing development genes, 19 metamorphosis genes, and 1,314 candidates. Of the 1,598 genes, 1,594 are included exclusively in cluster 4 with similar gene co-expression patterns. The network centrality analyses showed that wing development- and metamorphosis-related genes have a high degree of betweenness centrality and are expressed most highly in eggs, moderately in pupa and adults, and lowest in larva. This study provides some meaningful clues for elucidating the genetic modulation mechanism of wing development and metamorphosis in P. b. seulensis.

Warming undermines emergence success in a threatened alpine stonefly: A multi‐trait perspective on vulnerability to climate change

AbstractVulnerability to warming is often assessed using short‐term metrics such as the critical thermal maximum (CTMAX), which represents an organism's ability to survive extreme heat. However, the long‐term effects of sub‐lethal warming are an essential link to fitness in the wild, and these effects are not adequately captured by metrics like CTMAX.The meltwater stonefly,Lednia tumana, is endemic to high‐elevation streams of Glacier National Park, MT, USA, and has long been considered acutely vulnerable to climate‐change‐associated stream warming. As a result, in 2019, it was listed as Threatened under the U.S. Endangered Species Act. This presumed vulnerability to warming was challenged by a recent study showing that nymphs can withstand short‐term exposure to temperatures as high as ~27°C. But whether they also tolerate exposure to chronic, long‐term warming remained unclear.By measuring fitness‐related traits at several ecologically relevant temperatures over several weeks, we show thatL. tumanacannot complete its life‐cycle at temperatures only a few degrees above what some populations currently experience.The temperature at which growth rate was maximized appears to have a detrimental impact on other key traits (survival, emergence success and wing development), thus extending our understanding ofL. tumana's vulnerability to climate change.Our results call into question the use of CTMAXas a sole metric of thermal sensitivity for a species, while highlighting the power and complexity of multi‐trait approaches to assessing vulnerability.Read the freePlain Language Summaryfor this article on the Journal blog.

Aphid male wing polymorphisms are transient and have evolved repeatedly.

Polymorphic phenotypes have long been used to examine the maintenance of genetic variation within and between species. Most studies have focused on persistent polymorphisms, which are retained across species boundaries, and their positive effects on speciation rates. Far less is known about the macroevolutionary impacts of more transient polymorphisms, which are also common. Here we investigated male wing polymorphisms in aphids. We estimated the phylogenetic history of wing states across species, along with several other traits that could affect wing evolution. We found that male wing polymorphisms are transient: they are found in only ~4% of extant species, but have likely evolved repeatedly across the phylogeny. We reason that the repeated evolution of transient polymorphisms might be facilitated by the existence of the asexual female wing plasticity, which is common across aphids, and would maintain the wing development program even in species with wingless males. We also discovered that male wingedness correlates positively with host plant alternation and host plant breadth, and that winged morphs and wing polymorphisms may be associated with higher speciation rates. Our results provide new evolutionary insights into this well-studied group and suggest that even transient polymorphisms may impact species diversification rates.

Preliminary Study on Mechanical Properties of 3D-Printed Carbon-PLA Filament with Different Printing Orientation for SUAV Wings Application

This article focuses on the production of tensile test (ASTM D638-03) specimens using fused deposition modelling technique as preliminary study for preparation of 3D-printed SUAV wings. Carbon-PLA (nylon 6/66 copolymer adding with 20% of carbon fiber) was used as 3D filament. There were 7 printing orientations: 0o, 15o, 30o, 45o, 60o, 75o, and 90o based on tensile axis with 3 specimens for each direction (21 specimens in total). Printing parameters were set using open-source slicing application CURA. It was found delamination and fracture outside the gauge length causing high deviation of the mechanical properties value. So, the result of the testing test seems like do not comply with theoretical aspect of relationship between fiber orientation and tensile properties of composite materials. Taking care of printing parameters and increasing the number of specimens has an opportunity to achieve high precision results since precise data is crucial as a starting point for the development of SUAV wings.

Clathrin-dependent endocytosis plays a critical role in larval and pupal development, and female oocyte production in the red flour beetle (Tribolium castaneum).

Clathrin-dependent endocytosis is a vesicular transport process by which cells take macromolecules from the extracellular space to the intracellular space. It plays important roles in various cellular functions, but its biological significance in insect development and reproduction has not been well studied. We characterized and functionally analyzed four major clathrin-dependent endocytic pathway genes (TcChc, TcAP50, TcVhaSFD, TcRab7) in Tribolium castaneum. RNA interference (RNAi) by injecting double-stranded RNA (dsRNA) targeting each gene at three doses (50, 100, or 200 ng per insect) in 20-day-old larvae led to 100% larval mortality. When the expressions of TcChc, TcVhaSFD, and TcRab7 were suppressed by injecting their respective dsRNAs at each dose in 1-day-old pupae, the adults that emerged from the dsRNA-injected pupae were deformed, with the absence of wing development. The deformed adults died within 2 days after eclosion. When the expression of TcAP50 was suppressed by injecting its dsRNA into 1-day-old pupae, although no apparent deformed adults were observed, all the adults died within 35 days after eclosion. In addition, when the expressions of TcChc and TcVhaSFD were suppressed by injecting their respective dsRNAs at a reduced dose (10ng per insect) in 5-day-old pupae, the ovarian development and oocyte production in the resultant females were completely inhibited. Our results indicate that clathrin-dependent endocytosis is essential for insect development and reproduction. The results from this study can help researchers identify potential molecular targets for developing novel strategies for insect pest management. © 2023 Society of Chemical Industry.

Modeling & Simulation as Industry 4.0 enabling technology to support manufacturing process design: a real industrial application

This research work, first, briefly describes the educational offer of University of Calabria (UNICAL) related to Modeling & Simulation (M&S) and, secondly, presents a case study, developed by UNICAL students, as attempt to transfer the theoretical knowledge on M&S, gained over the university studies, into a real industrial application. As case study, the development of a new racing car front wing, from the mechanical design to the manufacturing process design and optimization, is presented. The manufacturing process design and optimization has been achieved by proposing an approach based on the combination of M&S tools, multiple design parameters and multiple performance measures. In particular, a simulation model has been used to assess the effect of different design parameters on several performance measure. The quantitative evaluation of the effects of the multiple design parameters on the multiple performance measures is achieved by using the Design of Experiments (DOE) being validated by means of the analysis of variance (ANOVA).

Transgenerational inheritance of wing development defects in Drosophila melanogaster induced by cadmium

The transgenerational inheritance of phenotype induced by environmental factors is a new focus in epigenetic research. In this study, Drosophila melanogaster (F0) was cultured in the medium containing cadmium (Cd, 4.5 mg/kg) from eggs to adults, and offspring (F1-F4) were continuously kept in standard medium (without cadmium). The phenotype analysis showed that cadmium induced developmental defects on wings and apoptosis in the wing disc cells of Drosophila (F0). The wing defects were transmitted for at least four generations even without Cd afterwards. And the effect on the mRNA expression of wing development related genes (shg, omb, F-actin, Mekk1) can be maintained for at least two or three generations. More importantly, under cadmium stress, the post-translational modification (PTM) on the histones H3K4me3 in the third instar larvae and ovaries or testes of adult flies increased significantly, while the levels of H3K9me3 and H3K27me3 decreased significantly. The expression of histone methylation related genes (dSet-1, ash1, Lsd1) increased significantly and these changes can be transmitted to offspring from one or two generations in ovaries or testes. These results suggest that the phenotypic defects of wings caused by cadmium can be inherited to the offspring, and this transgenerational inheritance effect may be related to the epigenetic regulation of histone methylation. Therefore, the adaptability of offspring should be considered when evaluating the toxicity and environmental risk of cadmium.

The morphogen Hedgehog is essential for proper adult morphogenesis in Bombyx mori

The well-known morphogen Hedgehog (Hh) is indispensable for embryo patterning and organ development from invertebrates to vertebrates. The role of Hh signaling pathway has been extensively investigated in the model organism Drosophila melanogaster, whereas its biological functions are still poorly understood in non-drosophilid insects. In the current study, we describe comprehensive investigation of Hh biological roles in the model lepidopteran insect Bombyx mori by using both CRISPR/Cas9-mediated gene ablation and Gal4/UAS-mediated ectopic expression. Direct injection of Cas9 protein and Hh-specific sgRNAs into preblastoderm embryos induced complete lethality. In contrast, Hh mutants obtained by the binary transgenic CRISPR/Cas9 system showed no deleterious phenotypes during embryonic and larval stages. However, mutants showed abnormalities from the pupal stage and most of adult body appendages exhibited severe developmental defects. Molecular analysis focused on wing development reveal that Hh signaling, Imd signaling and Wnt signaling pathways were distorted in Hh mutant wings. Ectopic expression by using the binary Gal4/UAS system induce early larval lethality. On contrary, moderate overexpression of Hh by using a unitary transgenic system resulted in severe defects in adult leg and antenna development. Our data directly provide genetic evidence that Hh plays vital roles in imaginal discs development and proper adult morphogenesis in B. mori.

HDAC3 Knockdown Dysregulates Juvenile Hormone and Apoptosis-Related Genes in Helicoverpa armigera

Insect development requires genes to be expressed in strict spatiotemporal order. The dynamic regulation of genes involved in insect development is partly orchestrated by the histone acetylation-deacetylation via histone acetyltransferases (HATs) and histone deacetylases (HDACs). Although histone deacetylase 3 (HDAC3) is required for mice during early embryonic development, its functions in Helicoverpa armigera (H. armigera) and its potential to be used as a target of insecticides remain unclear. We treated H. armigera with HDAC3 siRNA and RGFP966, a specific inhibitor, examining how the HDAC3 loss-of-function affects growth and development. HDAC3 siRNA and RGFP966 treatment increased mortality at each growth stage and altered metamorphosis, hampering pupation and causing abnormal wing development, reduced egg production, and reduced hatching rate. We believe that the misregulation of key hormone-related genes leads to abnormal pupa development in HDAC3 knockout insects. RNA-seq analysis identified 2788 differentially expressed genes (≥two-fold change; p ≤ 0.05) between siHDAC3- and siNC-treated larvae. Krüppel homolog 1 (Kr-h1), was differentially expressed in HDAC3 knockdown larvae. Pathway-enrichment analysis revealed the significant enrichment of genes involved in the Hippo, MAPK, and Wnt signaling pathways following HDAC3 knockdown. Histone H3K9 acetylation was increased in H. armigera after siHDAC3 treatment. In conclusion, HDAC3 knockdown dysregulated juvenile hormone (JH)-related and apoptosis-related genes in H. armigera. The results showed that the HDAC3 gene is a potential target for fighting H. armigera.

Mitochondria dysfunction impairs Tribolium castaneum wing development during metamorphosis

The disproportionate growth of insect appendages such as facultative growth of wings and exaggeration of beetle horns are examples of phenotypic plasticity. Insect metamorphosis is the critical stage for development of pupal and adult structures and degeneration of the larval cells. How the disproportionate growth of external appendages is regulated during tissue remodeling remains unanswered. Tribolium castaneum is used as a model to study the function of mitochondria in metamorphosis. Mitochondrial dysfunction is achieved by the knockdown of key mitochondrial regulators. Here we show that mitochondrial function is not required for metamorphosis except that severe mitochondrial dysfunction blocks ecdysis. Surprisingly, various abnormal wing growth, including short and wingless phenotypes, are induced after knocking down mitochondrial regulators. Mitochondrial activity is regulated by IIS (insulin/insulin-like growth factor signaling)/FOXO (forkhead box, sub-group O) pathway through TFAM (transcription factor A, mitochondrial). RNA sequencing and differential gene expression analysis show that wing-patterning and insect hormone response genes are downregulated, while programmed cell death and immune response genes are upregulated in insect wing discs with mitochondrial dysfunction. These studies reveal that mitochondria play critical roles in regulating insect wing growth by targeting wing development during metamorphosis, thus showing a novel molecular mechanism underlying developmental plasticity.

Chitinase 6 is required for procuticle thickening and organ shape in Drosophila wing.

The polysaccharide chitin is a major scaffolding molecule in the insect cuticle. In order to be functional, both chitin amounts and chitin organization have been shown to be important parameters. Despite great advances in the past decade, the molecular mechanisms of chitin synthesis and organization are not fully understood. Here, we have characterized the function of the Chitinase 6 (Cht6) in the formation of the wing, which is a simple flat cuticle organ, in the fruit fly Drosophila melanogaster. Reduction of Cht6 function by RNA interference during wing development does not affect chitin organization, but entails a thinner cuticle suggesting reduced chitin amounts. This phenotype is opposed to the one reported recently to be caused by reduction of Cht10 expression. Probably as a consequence, cuticle permeability to xenobiotics is enhanced in Cht6-less wings. We also observed massive deformation of these wings. In addition, the shape of the abdomen is markedly changed upon abdominal suppression of Cht6. Finally, we found that suppression of Cht6 transcript levels influences the expression of genes coding for enzymes of the chitin biosynthesis pathway. This finding indicates that wing epidermal cells respond to activity changes of Cht6 probably trying to adjust chitin amounts. Together, in a working model, we propose that Cht6-introduced modifications of chitin are needed for chitin synthesis to proceed correctly. Cuticle thickness, according to our hypothesis, is in turn required for correct organ or body part shape. The molecular mechanisms of this processes shall be characterized in the future.

Immune function analysis of LsSd, a transcription factor of the Hippo signaling pathway, in the cigarette beetle Lasioderma serricorne.

The Scalloped (Sd) is a transcription factor that regulates organ size control in the Hippo-signaling pathway. Recent studies have showed that Hippo signaling also functions in the innate immune response. Although the Sd gene has been reported in many insects, their immune functions remain unexplored. In this study, the LsSd gene of Lasioderma serricorne, with a complete open reading frame that encodes a protein composed of 402 amino acids was identified. LsSd was predominantly expressed in early pupae. Tissue-specific analyses revealed that the highest concentrations of LsSd were detected in the midgut and brain. At 1–24 h after Escherichia coli infection, LsSd expression increased substantially. However, LsSd expression was downregulated 3–12 h after Staphylococcus aureus infection. RNA interference-mediated silencing of the LsSd transcript resulted in deformed, considerably smaller, and degenerated wings. Meanwhile, LsCycE, LsDiap1, and LsVg, which are involved in cell proliferation and wing development, were drastically reduced when LsSd was depleted. In a survival assay, the LsSd knockdown considerably decreased the susceptibility to S. aureus, a gram-positive bacterium. In addition, knockdown of LsSd remarkably downregulated the transcription of LsCact in response to S. aureus stimulation, while upregulating the expression of five immune-related genes. Our results provide conclusive proof for the important roles of LsSd in the immune response of L. serricorne.

Preprint Highlight: Dynamic interplay of protrusive microtubule and contractile actomyosin forces drive tissue extension.

Cytoskeletal mechanical forces shape tissues during development. Although the role of the actomyosin machinery is extensively studied, how microtubules actively generate forces to shape tissues remains unknown. Combining in vivo experiments and simulations, this study elucidates that initial cell elongation during fly wing development is not driven by myosin contractility or external forces. Instead, protrusive forces generated by planar polarized noncentrosomal microtubules actively drive cell elongation, while myosin contractility is needed for final cell shape refinement. Thus ordered coordination between microtubules and actomyosin shapes the fly wing. This study will appeal to the broad cell and developmental biology community as it strengthens the growing notion that microtubules are active morphogenetic effectors. Beyond their core functions in cell division and intracellular transport, microtubule-mediated forces can directly dictate cell and tissue shape during development.

Chromatin remodeler Dmp18 regulates apoptosis by controlling H2Av incorporation in Drosophila imaginal disc development.

Programmed Cell Death (PCD) or apoptosis is a highly conserved biological process and plays essential roles both in the development and stress context. In Drosophila, expression of pro-apoptotic genes, including reaper (rpr), head involution defective (hid), grim, and sickle (skl), is sufficient to induce cell death. Here, we demonstrate that the chromatin remodeler Dmp18, the homolog of mammalian Znhit1, plays a crucial role in regulating apoptosis in eye and wing development. We showed that loss of Dmp18 disrupted eye and wing development, up-regulated transcription of pro-apoptotic genes, and induced apoptosis. Inhibition of apoptosis suppressed the eye defects caused by Dmp18 deletion. Furthermore, loss of Dmp18 disrupted H2Av incorporation into chromatin, promoted H3K4me3, but reduced H3K27me3 modifications on the TSS regions of pro-apoptotic genes. These results indicate that Dmp18 negatively regulates apoptosis by mediating H2Av incorporation and histone H3 modifications at pro-apoptotic gene loci for transcriptional regulation. Our study uncovers the role of Dmp18 in regulating apoptosis in Drosophila eye and wing development and provides insights into chromatin remodeling regulating apoptosis at the epigenetic levels.

Fatty acid binding protein is required for chitin biosynthesis in the wing of Drosophila melanogaster

Chitin, the major structural polysaccharide in arthropods such as insects and mites, is a linear polymer of N-acetylglucosamine units. The growth and development of insects are intimately coupled with chitin biosynthesis. The membrane-bound β-glycosyltransferase chitin synthase is known to catalyze the key polymerization step of N-acetylglucosamine. However, the additional proteins that might assist chitin synthase during chitin biosynthesis are not well understood. Recently, fatty acid binding protein (Fabp) has been suggested as a candidate that interacts with the chitin synthase Krotzkopf verkehrt (Kkv) in Drosophila melanogaster. Here, using split-ubiquitin membrane yeast two-hybrid and pull-down assays, we have demonstrated that the Fabp-B splice variant physically interacts with Kkv in vitro. The global knockdown of Fabp in D. melanogaster using RNA interference (RNAi) induced lethality at the larval stage. Moreover, in tissue-specific RNAi experiments, silenced Fabp expression in the epidermis and tracheal system caused a lethal larval phenotype. Fabp knockdown in the wings resulted in an abnormal wing development and uneven cuticular surface. In addition to reducing the chitin content in the first longitudinal vein of wings, Fabp silencing also caused the loss of procuticle laminate structures. This study revealed that Fabp plays an important role in chitin synthesis and contributes to a comprehensive understanding of the complex insect chitin biosynthesis.

Comparative transcriptional analysis and identification of hub genes associated with wing differentiation of male in Aphis gossypii

BackgroundAphis gossypii Glover (Hemiptera: Aphididae), a worldwide polyphagous phloem-feeding agricultural pest, has three wing morphs (winged parthenogenetic female, gynopara, and male) in the life cycle. The exclusive males could fly from summer hosts to winter hosts, which are essential for gene exchanges of cotton aphid populations from different hosts or regions. However, the molecular mechanism of wing differentiation of male in A. gossypii remains unclear.ResultsMorphological observation of male A. gossypii showed that there is no distinct difference in the external morphologies of the 1st and 2nd instar nymphs. The obvious differentiation of wing buds started in the 3rd instar nymph and was visible via naked eyes in the 4th instar nymphal stage, then adult male emerged with full wings. According to morphological dynamic changes, the development of wings in males were divided into four stages: preliminary stage (the 1st instar to 2nd instar), prophase (the 3rd instar), metaphase (the 4th instar), anaphase (the 5th instar). Results of feeding behavior monitoring via EPG (electrical penetration graph) technology indicated that although the male cotton aphids had strong desire to feed (longer duration of C 55.24%, F 5.05% and Pd waves 2.56%), its feeding efficiency to summer host cotton was low (shorter E1 3.56% and E2 waves 2.63%). Dynamic transcriptome analysis of male aphid at 5 different developmental periods showed that in the 3rd instar nymph, the number of up-regulated DEGs was significant increased, and time-course gene transcriptional pattern analyses results also showed that numerous genes categorized in clusters 3, 5, and 8 had the highest expressed levels, which were consistent with morphological changes of wing buds. These results indicate that the 3rd instar nymph is the critical stage of wing bud differentiation in males. Furthermore, through pathway enrichment analysis of DEGs and WGCNA, it revealed that the neuroactive ligand-receptor interaction, Ras signaling pathway, dopaminergic synapse, circadian entrainment and the corresponding hub genes of PLK1, BUB1, SMC2, TUBG, ASPM, the kinesin family members (KIF23, KIF20, KIF18-19) and the novel subfamily of serine/threonine (Aurora kinase A and Aurora kinase B) probably played an important role in the critical stage of wing bud differentiation.ConclusionThis study explored morphological changes and genes transcriptional dynamics males in cotton aphid, revealed the phenomenon of low feeding efficiency of winged males on summer host cotton, and identified key signaling pathways and potential hub genes potentially involved in wing bud differentiation of male in A. gossypii.

Distinct mechanisms of planar polarization by the core and Fat-Dachsous planar polarity pathways in the Drosophila wing.

Planar polarity describes the coordinated polarization of cells within a tissue plane, and in animals can be determined by the "core" or Fat-Dachsous pathways. Current models for planar polarity establishment involve two components: tissue-level "global" cues that determine the overall axis of polarity and cell-level feedback-mediated cellular polarity amplification. Here, we investigate the contributions of global cues versus cellular feedback amplification in the core and Fat-Dachsous pathways during Drosophila pupal wing development. We present evidence that these pathways generate planar polarity via distinct mechanisms. Core pathway function is consistent with strong feedback capable of self-organizing cell polarity, which can then be aligned with the tissue axis via weak or transient global cues. Conversely, generation of cell polarity by the Ft-Ds pathway depends on strong global cues in the form of graded patterns of gene expression, which can then be amplified by weak feedback mechanisms.