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PloS One 2024Sexual dimorphism is common throughout the animal kingdom, leading to sex-specific phenotypic differences. The common whitetail skimmer dragonfly, Plathemis lydia...
Sexual dimorphism is common throughout the animal kingdom, leading to sex-specific phenotypic differences. The common whitetail skimmer dragonfly, Plathemis lydia (Drury, 1773), is sexually dichromatic, where males of this species display a conspicuous white abdomen and females display a dark brown abdomen. Differences in abdomen conspicuousness between male and female P. lydia are likely attributed to differences in selective pressure where males use their white conspicuous abdomen during male-male territorial chases. We hypothesized that male P. lydia would exhibit wing morphology adaptations to better offset the costs of predation and territoriality and that these adaptations would differ from females. We used field-collected images to quantify differences in body length, wing length, wing area, wing shape, and wing loading between male and female P. lydia. Our results show that male P. lydia have significantly shorter fore and hind wings relative to body size with a higher wing loading when compared to females. We also found that male P. lydia have narrower and pointier fore and hind wings compared to females. These results are consistent with the idea that males are adapted for faster flight, specifically higher acceleration capacity, and higher agility whereas females are adapted for higher maneuverability.
Topics: Animals; Male; Wings, Animal; Odonata; Female; Sex Characteristics; Body Size
PubMed: 38809838
DOI: 10.1371/journal.pone.0303690 -
Nature Communications May 2024Birds are represented by 11,000 species and a great variety of body masses. Modular organisation of trait evolution across birds has facilitated simultaneous adaptation...
Birds are represented by 11,000 species and a great variety of body masses. Modular organisation of trait evolution across birds has facilitated simultaneous adaptation of different body regions to divergent ecological requirements. However, the role modularity has played in avian body size evolution, especially small-bodied, rapidly evolving and diverse avian subclades, such as hummingbirds and songbirds, is unknown. Modularity is influenced by the intersection of biomechanical restrictions, adaptation, and developmental controls, making it difficult to uncover the contributions of single factors such as body mass to skeletal organisation. We develop a novel framework to decompose this complexity, assessing factors underlying the modularity of skeletal proportions in fore-limb propelled birds distributed across a range of body masses. We demonstrate that differences in body size across birds triggers a modular reorganisation of flight apparatus proportions consistent with biomechanical expectations. We suggest weakened integration within the wing facilitates radiation in small birds. Our framework is generalisable to other groups and has the capacity to untangle the multi-layered complexity intrinsic to modular evolution.
Topics: Animals; Wings, Animal; Body Size; Biological Evolution; Birds; Flight, Animal; Biomechanical Phenomena
PubMed: 38806471
DOI: 10.1038/s41467-024-48324-y -
PloS One 2024One of the most challenging aspects of bee ecology and conservation is species-level identification, which is costly, time consuming, and requires taxonomic expertise....
One of the most challenging aspects of bee ecology and conservation is species-level identification, which is costly, time consuming, and requires taxonomic expertise. Recent advances in the application of deep learning and computer vision have shown promise for identifying large bumble bee (Bombus) species. However, most bees, such as sweat bees in the genus Lasioglossum, are much smaller and can be difficult, even for trained taxonomists, to identify. For this reason, the great majority of bees are poorly represented in the crowdsourced image datasets often used to train computer vision models. But even larger bees, such as bumble bees from the B. vagans complex, can be difficult to separate morphologically. Using images of specimens from our research collections, we assessed how deep learning classification models perform on these more challenging taxa, qualitatively comparing models trained on images of whole pinned specimens or on images of bee forewings. The pinned specimen and wing image datasets represent 20 and 18 species from 6 and 4 genera, respectively, and were used to train the EfficientNetV2L convolutional neural network. Mean test precision was 94.9% and 98.1% for pinned and wing images respectively. Results show that computer vision holds great promise for classifying smaller, more difficult to identify bees that are poorly represented in crowdsourced datasets. Images from research and museum collections will be valuable for expanding classification models to include additional species, which will be essential for large scale conservation monitoring efforts.
Topics: Bees; Animals; Deep Learning; Wings, Animal; Image Processing, Computer-Assisted; Neural Networks, Computer; Species Specificity
PubMed: 38805521
DOI: 10.1371/journal.pone.0303383 -
Frontiers in Veterinary Science 2024Foot health is crucial for elephants, as pathological lesions of the feet are a leading cause of euthanasia in captive elephants, which are endangered species. Proper...
INTRODUCTION
Foot health is crucial for elephants, as pathological lesions of the feet are a leading cause of euthanasia in captive elephants, which are endangered species. Proper treatment of the feet, particularly in conditions affecting the digits and the digital cushion, requires a thorough understanding of the underlying anatomy. However, only limited literature exists due to the small population and the epidemiological foot diseases which often precludes many deceased elephants from scientific study. The aim of this study was to provide a detailed anatomical description of the blood supply to the African elephant's hindfoot.
METHODS
The healthy right hindlimb of a 19-year-old deceased female African savanna elephant was examined using computed tomography. Following a native sequence, 48 mL of barium-based contrast agent was injected into the caudal and cranial tibial arteries, and a subsequent scan was performed. The images were processed with 3D Slicer software.
RESULTS
The medial and lateral plantar arteries run in a symmetrical pattern. They each have a dorsal and a plantar branch, which reach the plantar skin before turning toward the axial plane of the sole to reach the digital cushion from the proximal direction. An accurate 3D model of the arteries and the bones of the foot, a set of labeled images and an animation of the blood supply have been created for ease of understanding.
DISCUSSION
In contrast to domestic ungulates, the digital cushion of the hindlimb is supplied differently from that of the forelimb. The lack of large vessels in its deeper layers indicates a slow regeneration time. This novel anatomical information may be useful in the planning of surgical interventions and in emergency medical procedures.
PubMed: 38803804
DOI: 10.3389/fvets.2024.1399392 -
BioRxiv : the Preprint Server For... May 2024Though hierarchy is commonly invoked in descriptions of motor cortical function, its presence and manifestation in firing patterns remain poorly resolved. Here we use...
Though hierarchy is commonly invoked in descriptions of motor cortical function, its presence and manifestation in firing patterns remain poorly resolved. Here we use optogenetic inactivation to demonstrate that short-latency influence between forelimb premotor and primary motor cortices is asymmetric during reaching in mice, demonstrating a partial hierarchy between the endogenous activity in each region. Multi-region recordings revealed that some activity is captured by similar but delayed patterns where either region's activity leads, with premotor activity leading more. Yet firing in each region is dominated by patterns shared between regions and is equally predictive of firing in the other region at the single-neuron level. In dual-region network models fit to data, regions differed in their dependence on across-region input, rather than the amount of such input they received. Our results indicate that motor cortical hierarchy, while present, may not be exposed when inferring interactions between populations from firing patterns alone.
PubMed: 38798685
DOI: 10.1101/2023.09.23.559136 -
Genes Apr 2024Hairless (H) encodes the major antagonist in the Notch signaling pathway, which governs cellular differentiation of various tissues in . By binding to the Notch signal...
Hairless (H) encodes the major antagonist in the Notch signaling pathway, which governs cellular differentiation of various tissues in . By binding to the Notch signal transducer Suppressor of Hairless (Su(H)), H assembles repressor complexes onto Notch target genes. Using genome engineering, three new alleles, , and were generated and a phenotypic series was established by several parameters, reflecting the residual H-Su(H) binding capacity. Occasionally, homozygous flies develop to adulthood. They were compared with the likewise semi-viable allele affecting H-Su(H) nuclear entry. The homozygotes were short-lived, sterile and flightless, yet showed largely normal expression of several mitochondrial genes. Typical for mutants, both and homozygous alleles displayed strong defects in wing venation and mechano-sensory bristle development. Strikingly, however, displayed only a loss of bristles, whereas bristle organs of flies showed a complete shaft-to-socket transformation. Apparently, the impact of is restricted to lateral inhibition, whereas that of also affects the respective cell type specification. Notably, reduction in gene dosage only suppressed the bristle phenotype, but amplified that of . We interpret these differences as to the role of H regarding Su(H) stability and availability.
Topics: Animals; Drosophila Proteins; Alleles; Drosophila melanogaster; Wings, Animal; Transcription Factors; Gene Expression Regulation, Developmental; Repressor Proteins; Receptors, Notch; Signal Transduction
PubMed: 38790181
DOI: 10.3390/genes15050552 -
Biomolecules Apr 2024Suppressor of deltex () is a member of the NEDD4 family of the HECT domain E3 ubiquitin ligases. acts as a regulator of Notch endocytic trafficking, promoting Notch...
Suppressor of deltex () is a member of the NEDD4 family of the HECT domain E3 ubiquitin ligases. acts as a regulator of Notch endocytic trafficking, promoting Notch lysosomal degradation and the down-regulation of both ligand-dependent and ligand-independent signalling, the latter involving trafficking through the endocytic pathway and activation of the endo/lysosomal membrane. Mutations of result in developmental phenotypes in the wing that reflect increased Notch signalling, leading to gaps in the specification of the wing veins, and functions to provide the developmental robustness of Notch activity to environmental temperature shifts. The full developmental functions of are unclear; however, this is due to a lack of a clearly defined null allele. Here we report the first defined null mutation of , generated by P-element excision, which removes the complete open reading frame. We show that the mutation is recessive-viable, with the Notch gain of function phenotypes affecting wing vein and leg development. We further uncover new roles for in oogenesis, where it regulates interfollicular stalk formation, egg chamber separation and germline cyst enwrapment by the follicle stem cells. Interestingly, while the null allele exhibited a gain in Notch activity during oogenesis, the previously described allele, which carries a seven amino acid in-frame deletion, displayed a Notch loss of function phenotypes and an increase in follicle stem cell turnover. This is despite both alleles displaying similar Notch gain of function in wing development. We attribute this unexpected context-dependent outcome of being due to the partial retention of function by the intact C2 and WW domain regions of the protein. Our results extend our understanding of the developmental role of in the tissue renewal and homeostasis of the ovary and illustrate the importance of examining an allelic series of mutations to fully understand developmental functions.
Topics: Animals; Oogenesis; Drosophila melanogaster; Drosophila Proteins; Receptors, Notch; Alleles; Female; Wings, Animal; Mutation; Signal Transduction; Phenotype; Membrane Proteins
PubMed: 38785929
DOI: 10.3390/biom14050522 -
F1000Research 2024Motor learning is central to human existence, such as learning to speak or walk, sports moves, or rehabilitation after injury. Evidence suggests that all forms of motor...
BACKGROUND
Motor learning is central to human existence, such as learning to speak or walk, sports moves, or rehabilitation after injury. Evidence suggests that all forms of motor learning share an evolutionarily conserved molecular plasticity pathway. Here, we present novel insights into the neural processes underlying operant self-learning, a form of motor learning in the fruit fly
METHODS
We operantly trained wild type and transgenic fruit flies, tethered at the torque meter, in a motor learning task that required them to initiate and maintain turning maneuvers around their vertical body axis (yaw torque). We combined this behavioral experiment with transgenic peptide expression, CRISPR/Cas9-mediated, spatio-temporally controlled gene knock-out and confocal microscopy.
RESULTS
We find that expression of atypical protein kinase C (aPKC) in direct wing steering motoneurons co-expressing the transcription factor is necessary for this type of motor learning and that aPKC likely acts via non-canonical pathways. We also found that it takes more than a week for CRISPR/Cas9-mediated knockout of in adult animals to impair motor learning, suggesting that adult expression is required for operant self-learning.
CONCLUSIONS
Our experiments suggest that, for operant self-learning, a type of motor learning in , co-expression of atypical protein kinase C (aPKC) and the transcription factor is necessary in direct wing steering motoneurons. Some of these neurons control the wing beat amplitude when generating optomotor responses, and we have discovered modulation of optomotor behavior after operant self-learning. We also discovered that aPKC likely acts via non-canonical pathways and that FoxP expression is also required in adult flies.
Topics: Animals; Protein Kinase C; Motor Neurons; Drosophila Proteins; Drosophila melanogaster; Learning; Forkhead Transcription Factors; Wings, Animal; Animals, Genetically Modified; Neuronal Plasticity; Conditioning, Operant; CRISPR-Cas Systems; Drosophila
PubMed: 38779314
DOI: 10.12688/f1000research.146347.1 -
F1000Research 2023How the precise spatial regulation of genes is correlated with spatial variation in chromatin accessibilities is not yet clear. Previous studies that analysed chromatin...
How the precise spatial regulation of genes is correlated with spatial variation in chromatin accessibilities is not yet clear. Previous studies that analysed chromatin from homogenates of whole-body parts of insects found little variation in chromatin accessibility across those parts, but single-cell studies of brains showed extensive spatial variation in chromatin accessibility across that organ. In this work we studied the chromatin accessibility of butterfly wing tissue fated to differentiate distinct colors and patterns in pupal wings of We dissected small eyespot and adjacent control tissues from 3h pupae and performed ATAC-Seq to identify the chromatin accessibility differences between different sections of the wings. We observed that three dissected wing regions showed unique chromatin accessibilities. Open chromatin regions specific to eyespot color patterns were highly enriched for binding motifs recognized by Suppressor of Hairless (Su(H)), Krüppel (Kr), Buttonhead (Btd) and Nubbin (Nub) transcription factors. Genes in the vicinity of the eyespot-specific open chromatin regions included those involved in wound healing and SMAD signal transduction pathways, previously proposed to be involved in eyespot development. We conclude that eyespot and non-eyespot tissue samples taken from the same wing have distinct patterns of chromatin accessibility, possibly driven by the eyespot-restricted expression of potential pioneer factors, such as Kr.
Topics: Animals; Butterflies; Chromatin; Wings, Animal; Pigmentation; Insect Proteins; Transcription Factors
PubMed: 38778811
DOI: 10.12688/f1000research.133789.1 -
Nature Communications May 2024As natural predators, owls fly with astonishing stealth due to the serrated feather morphology that produces advantageous flow characteristics. Traditionally, these...
As natural predators, owls fly with astonishing stealth due to the serrated feather morphology that produces advantageous flow characteristics. Traditionally, these serrations are tailored for airfoil edges with simple two-dimensional patterns, limiting their effect on noise reduction while negotiating tradeoffs in aerodynamic performance. Conversely, the intricately structured wings of cicadas have evolved for effective flapping, presenting a potential blueprint for alleviating these aerodynamic limitations. In this study, we formulate a synergistic design strategy that harmonizes noise suppression with aerodynamic efficiency by integrating the geometrical attributes of owl feathers and cicada forewings, culminating in a three-dimensional sinusoidal serration propeller topology that facilitates both silent and efficient flight. Experimental results show that our design yields a reduction in overall sound pressure levels by up to 5.5 dB and an increase in propulsive efficiency by over 20% compared to the current industry benchmark. Computational fluid dynamics simulations validate the efficacy of the bioinspired design in augmenting surface vorticity and suppressing noise generation across various flow regimes. This topology can advance the multifunctionality of aerodynamic surfaces for the development of quieter and more energy-saving aerial vehicles.
Topics: Animals; Flight, Animal; Wings, Animal; Feathers; Hemiptera; Strigiformes; Hydrodynamics; Computer Simulation; Biomechanical Phenomena
PubMed: 38773081
DOI: 10.1038/s41467-024-48454-3