Belgium

Trap-jaw ants are recognized for their generally elongated mandibles that snap at remarkable speeds, having evolved among nine genera and three subfamilies. Despite superficial similarities, mandible morphology varies considerably, potentially affecting bite performance. To investigate these effects, we measured functional traits — mechanical advantage, cuticle thickness, and second moment of area (I) — and conducted finite element analysis (FEA) simulating a strike bite on 3D mandible reconstructions of 25 species from eight genera and two subfamilies of trap-jaw ants. We performed Principal Component Analysis with the functional traits and FEA-derived stress values and hypothesized that species distribution in this multivariate space would reflect their phylogenetic relationships. Species mostly grouped with their generic relatives, except Anochetus and Orecthognathus, which showed broader distributions. The distribution of trap-jaw genera also resembled their phylogenetic relatedness, but Myrmicinae and Ponerinae subfamilies did not form distinct clusters, as was initially anticipated. FEA stress data were relevant for grouping species with more elongated mandibles, such as Acantognathus spp. and Strumigenys denticulata. Odontomachus spp. and Daceton armigerum clustered due to their higher values ofI normalised by cross-section shape. Strumigenys spp. with shorter mandibles grouped due to their high mechanical advantage, I corrected by mandible length, cuticle thickness, and the low-stress values they exhibited under bite loading. Although our results only partially support the hypothesis that mandible function aligns with the phylogenetic relationships of trap-jaw ants, they highlight the functional consequences of mandible morphological variation in the context of the outstanding strike impacts these ants are submitted to.

SEB Conference 2025

Morphology drives functional performance variation: the case of trap-jaw ant mandibles

power-amplification mechanisms

mechanical performance

biting apparatus

poster

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The arboreal environment is a complex three-dimensional environment that presents functional challenges. Despite these challenges, many clades of tetrapods have colonised this environment independently. So far, only a handful of studies investigate the impact of living in trees on the morphology in a large macroevolutionary sample. Here, we investigate whether there is an effect of degree of arboreality on radius shape. To do so, we compared radius shape across arboreal and terrestrial species of carnivorans and primates. Radius shape is an interesting structure as it influences forearm movement and hand position, which are vital in arboreal environments. Our sample comprises 239 specimens belonging to 160 species and, is representative of the locomotor diversity of carnivorans and primates. We used 3D geometric morphometrics to quantify the shape of the radius. Comparative phylogenetic methods were applied to understand the influence of size, locomotion and evolutionary history of each clade on radial shape. Our results showed a significant impact of the locomotion and morphological similarities in the radial shape among species with similar arboreal locomotion. Furthermore, the morphological diversity of radial shapes in carnivorans and primates is low, in contrast to the high diversity observed in terrestrial species. This suggests that arboreal environments impose greater constraints on the radial morphology in carnivorans and primates, which is consistent with results obtained in other vertebrates.

Arboreal adaptations constrain the morphological evolution of the radius bone in primates and carnivorans.

Legs can perform many functions, but fundamentally their ‘purpose’ is to support body weight while the body travels.  To do this effectively, the structures, mechanisms and actions of the legs should 1) avoid avoidable mechanical work demand, 2) allow economical supply of mechanical work, while 3) be simple and robust to control. Recent work considering ‘legs as linkages’ focuses on these roles. Sequences of isometric muscle actions result in a work-avoiding ‘sliding’ motion of the body over the foot (role 1); in the human, this would account for gluteus, then vastus, then rectus femoris (forming a 4-bar linkage) tensions. Given a limited peak muscle power, and a cost to muscle activation, work is provided economically (role 2) with muscles that contract over the entire stance; in running humans this would be the hamstrings that provide mechanical power without altering the work-avoiding geometries of role 1. And the sequence of linkages resulting in sliding (role 1) engage muscles through simple changes in geometry (role 3). Early application of these principles to a range of toy and human-scale models will be presented. These demonstrate the potential for bio-convergent linkages to facilitate work-avoidance, powering economy, and simplified control in engineered leg design.

Legs as linkages, legs as machines, legs as toys… and for robots?

The dermapteran hindwing is known for its bistable properties, resulting from the interplay of folding geometry and anisotropic distribution of resilin, a protein capable of storing elastic energy. These properties present compelling possibilities for the space industry, aiming to reduce weight and stowing volume of spacecraft by using minimal actuation to deploy structures like solar panels or satellite drag sails. Our research introduces a computational tool, built on top of the open source MuJoCo library, to simulate the biomechanics of wing folding. Initially focusing on the fan-folded area of the hindwing, we demonstrate a bistable system, including both a locked open state and a closing mechanism. This tool reproduces the dynamics of the dermapteran hindwing fan folding as a function of key design parameters. These parameters include geometry, mass, stiffness and actuation, allowing predictions on the structure’s behaviour across different scales. Results demonstrate successful closing within 90 seconds of wing structures with a radius of approximately 50 cm. Closing can be achieved by applying at torques of 20 Ncm locally in the centre of the radial fan. This leads to elastic energy release of tendons, with a stiffness of 30 N/cm, which are substituting the resilin found in the broadened vein patches. Consequently, the wing sections fold, representing a global deformation. The tool demonstrates successful upscaling of the small wing, while preserving the general properties of the bistable system. It serves as a foundation for further software development and engineering of biomimetic, deployable structures for the space industry.

Unlocking bistability: computational tool for the simulation of dermapteran hindwing folding

Actuation has been identified as a significant limiting factor for turbulence mitigation of aircraft. Turning to nature for inspiration enables an understanding of how highly agile birds can articulate their aerodynamic surfaces during precision flight conditions such as wind hovering. Such understanding can inspire morphing actuation that enable higher control authority and rapidity, improving flight performance in challenging scenarios. This paper, therefore, explores the effects of specific kestrel morphing motions using a high-fidelity morphing robot of a kestrel, which replicates predominant motions seen in real wind-hovering kestrels. Through comprehensive wind tunnel testing, the aerodynamic effects and stability implications of wing extension, tail spread, and tail incidence mechanisms are examined. The findings illustrate redundancy in control axes, enabling the birds to trim for stability through their area changing degrees-of-freedom. The coupling of wing and tail extension, seen in real flight, not only facilitates improved lift generation but also effectively decouples lift and pitching moment axes, reflecting strategies observed in real kestrel flight. The remarkably low inertia of kestrels, extracted through CT scanning, is found to be an important contributor to the agility advantage of kestrels versus similar sized aircraft. This study highlights the significant potential of bio-inspired morphing, providing fresh perspectives on control strategies informed by nature's flight mechanisms.

Kestrel morphing reveals stability tailoring and aerodynamic benefits of wing-tail coupling in wind-hovering flight

Vitamin C (VC), also known as ascorbic acid and ascorbate, is a water-soluble antioxidant in plants that promotes skin health and immune function in humans. Spinach (Spinacia oleracea L.), a leafy green vegetable widely valued for its health benefits, has been identified as a target for nutritional enhancement, including increased VC content. However, the complex inheritance of VC necessitates advanced selection methods to accelerate cultivar development. In this study, VC- associated single nucleotide polymorphism (SNP) markers identified through genome-wide association (GWAS) were employed for genomic prediction (GP) to estimate prediction accuracy (PA) for VC content in spinach. A dataset of 147,977 SNPs generated from whole genome resequencing was analyzed in a panel of 347 spinach genotypes using six GWAS models. Sixty-two SNP markers, distributed across six spinach chromosomes, were significantly associated with VC content. PA was assessed using randomly selected SNP sets and GWAS-derived SNP marker sets across various GP models. Results demonstrated that PA exceeded 40% when using 1,000 or more SNPs. Furthermore, incorporating GWAS-derived SNP markers improved PA, achieving a r-value greater 0.70 through Bayes ridge regression (BRR) model. This study highlights the potential of GWAS-derived SNP markers for marker-assisted selection (MAS) and genomic selection (GS) in spinach breeding programs aimed at enhancing VC content.

Genomic Prediction of Vitamin C Content in Spinach

Overall plant architecture (consisting of the number, spacing and angle of secondary root and shoot branches) determines the efficiency of crops to capture essential resources such as water and nutrients below-ground, and light above-ground. Plant architecture is critically regulated by gravitropic growth, and recently, members of the highly conserved LAZYgene family have been demonstrated to play crucial roles in regulation of branching angle, a key determinant of plant architecture. Our previous work identified a novel dominant point mutation in LAZY4, (described as lazy4D) through an EMS mutagenesis screen in the model plant, Arabidopsis. Lateral roots in the lazy4Dmutant demonstrate steeper rooting, a highly desirable trait, that maximises nitrogen uptake, drought tolerance and carbon sequestration in cereal crops, making LAZY4 (and related LAZY genes) attractive targets for gene-editing to engineer deeper rooting in crop plants. However, the mechanistic basis for LAZY4dependent-regulation of root angle remains uncharacterised. Using live cell bioimaging and molecular genetic techniques, we determined that lazy4Dinfluences root growth angle in a dose-dependent manner, and further, that root LAZYs interact with D6PK proteins to regulate PIN polarisation and/or activity to regulate  lateral root growth angle.  Further we show that an MKK-MPK31,2  phosphorylation module is required forLAZY4, but notlazy4d dependent regulation of growth angle. Collectively, our work sheds novel insights into the molecular mechanisms that underpin thelazy4D (and more broadly,LAZY) dependent regulation of root and shoot branching angle in flowering plants.

LAZY but effective: The role ofLAZYgenes in regulating lateral root gravitropic setpoint angle (GSA)

Ectopic expression of a cytochrome P450 enzyme-encoding gene PLASTOCHRON1(PLA1/ZmCYP78A1) leads to increased biomass and seed yield potential by extending the duration of cell division, as demonstrated by multi-year and multi-location field trials. The expression pattern of PLA1 in the maize shoot apical meristem resembles a boundary region between meristematic and differentiated cells, where cells divide more rapidly and begin transitioning. We refer to these PLA1-expressing cells as transit amplifying cells (TACs), in analogy with similar cell types in animal systems. However, the precise mechanism of enzymatic reaction of PLA1 and its surrounding gene network in TACs remain unclear. To address these gaps, we utilize targeted spatial transcriptomics in the maize shoot apex to spatially map gene distribution and apply multiplex genome editing to investigate the genetic interactions of PLA1 co-expressing genes in TACs. Additionally, we use a cell-free protein expression system to stably and purely synthesize PLA1 for target binding assays to identify its substrate-product pair. These findings will advance both fundamental and applied research, deepening our understanding of growth, cell differentiation, and leaf initiation in the shoot apical meristem; and they will facilitate the fine-tuning of key growth genes through genetic engineering and the utilization of enzymatic characteristics to enhance crop traits.

Deciphering the Role of PLASTOCHRON1 in Transit Amplifying Cells in Maize Yield through Spatial Transcriptomics and Enzymatic Characterization

Saffron is a high-value spice renowned for its stigma, yet the genetic and molecular mechanisms governing its flowering remain poorly understood. This study investigates the role of key flowering regulators in saffron, focusing on the Florigen Activation Complex (FAC) componentsFLOWERING LOCUS T(FT) and the bZIP transcription factorFD. WhereTFL1serves a contrasting role by repressing flowering. Floral induction is modulated by the balance between two flowering-related proteins,FLOWERING LOCUS T (FT)andTERMINAL FLOWERING LIKE 1(TFL1).
 We identified sixFThomologs (CsatFT1-6), threeFDhomologs (CsatFD1-3) and threeTFL1(TFL1-1-TFL1-3) in saffron. Spatiotemporal expression profiling showed thatCsatFT3andCsatFD2are specifically expressed in the floral meristem and coincide with floral induction. In contrast,CsatTFL1-3downregulates in apices during flower induction, suggesting thatCsatTFL1-3has a role in floral repression. Using BiFC and Y2H assay techniques, we confirmed the interaction betweenCsatFT3/CsatFD2andCsatFD2/TFL1-3. Functional characterization through Arabidopsis and ViGS in saffron demonstrated thatCsatFT3andCsatFD2positively whereasCsatTFL1-3negatively regulates floral induction.
Short vegetative phase(SVP) is particularly responsive to temperature changes, as the saffron flowering is highly temperature sensitive, we have identified twoCsatSVPgenes. Notably,CsatFT3is regulated by the transcription factorCsatSVP2. Binding and activation studies indicate thatCsatSVP2negatively regulatesCsatFT3. Additionally, interactions betweenCsatFT3andCsatSVP2were confirmed using the luciferase assay, and Y1H technique. Overall, the study uncovers components of the floral induction in saffron, offering the potential for genetic improvements to address sterility and enhance yield through targeted manipulation.

Bud to Bloom:Decoding Transcriptional Network Underlying Flowering Regulation in Saffron (Crocus sativusL.)

Citrus greening or Huanglongbing, and potato zebra chip are devastating diseases affecting worldwide citrus and potato production. The diseases are associated with the fastidious (unculturable), phloem-limited bacteria, ‘Ca. Liberibacter spp.’ and are transmitted by insect vectors. Defensins are short (~40 to 50 amino acids) basic, cysteine-rich peptides integral to the innate immune system in plants, animals, and insects and possess broad-spectrum inhibitory activity against bacterial and fungal pathogens. Here, we evaluated whether expressing defensins from spinach in citrus and potato can confer tolerance to ‘Ca. Liberibacter spp.’ diseases. Given the unculturable nature of ‘Ca. Liberibacter spp.’, efficacy evaluation of two spinach defensins (SoAMP1 and SoAMP2), was first performed using the ex vivo microbial hairy root system. Both SoAMP1 and SoAMP2 demonstrated significant antimicrobial activity against ‘Ca. Liberibacter spp.’ in citrus and potato hairy roots compared to controls. The spinach defensins disrupted bacterial cell membranes and permeability, leading to mortality, as demonstrated by in vitro cytotoxicity assays using a culturable surrogate bacteria, Liberibacter crescens. Furthermore, heterologous expression of SoAMP1 and SoAMP2 in potatoes and citrus using genetic engineering or viral vector-mediated expression conferred plant tolerance to ‘Ca. Liberibacter spp.’ and significantly improved crop yield of infected plants. In conclusion, one or more spinach defensin peptides could be used as crop protection products for managing citrus greening, potato zebra chip, and/or other diseases.

Novel antimicrobial peptides from spinach confer tolerance to citrus greening and potato zebra chip diseases.

The development of growth systems for cultivation in space aims at minimizing the resources required in terms of energy and volume. This technological progress affects also the plant organisms used, where the optimization of the plant architecture and productivity in a controlled environment will be fundamental to maximize space efficiency and reduce waste. In this context, for example, the generation and selection of crop dwarf varieties, which makes crops compatible with efficient vertical farming systems, is a rapidly expanding field for the first space settlements. An ideal space crop, however, should also be highly productive, optimised for growth in a closed environment and resistant to space stressors.
Most calories in the human diet come from complex carbohydrates, obtained mainly from the cultivation of cereals. Among cereals, rice is currently the main source of energy for the world population. Rice has interesting nutraceutical characteristics: it contains small and readily digestible starch, does not contain gluten and, depending on the variety, can provide fibre, proteins, vitamin B, iron and manganese. Rice is also one of the highest yielding cereals and can be easily grown with soilless methodologies (e.g., hydroponics), which are currently considered the most adapted technologies and potentially applicable to space exploration scenarios.
Starting from the identification of the ideal ideotype, the project Moon-Rice aims at developing new varieties of rice, selected specifically for future space applications.

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Arboreal adaptations constrain the morphological evolution of the radius bone in primates and carnivorans.

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