Insect Morphology Research Articles

Multibody system dynamics for bio-robotic design and simulation based on inching-locomotion caterpillar's gait: MBD-ILAR method.

Inching-locomotion caterpillars (ILAR) inspire the design of "inch-worm" robots with biomimicry features, that can be adapted to different environments, such as natural, man-made, or other planets. Therefore, this work defines a novel mathematical method called Multi-Body Dynamics for Inching-Locomotion Caterpillar Robots (MBD-ILAR) to standardize the gait simulation of this type of machines, including a payload over the head to carry an object. The method is composed of 3 steps: (i) setting the model, where the input data is defined by: the phases of walk-stride (PHAWS) based on the bioinspired robotic design (BIROD) method, linkage dimensions of insect's morphology based on the geometrical kinematic analysis (GEKINS) algorithm, the joint types, the link's mass and center of mass, and the gravity constant. Then, (ii) kinematic analysis: to solve the orientation, velocity, and acceleration; and (iii) dynamic analysis: to obtain the joint forces, attachment forces to the ground, motor's torque, and mechanical power. The method was applied in a case study adapting the dimensions of a real specimen - Geometridae sp. (35000 species), for that purpose, a graphical user interface (GUI) was developed in order to get the biomechanical results that guarantee the robot's actuator selection: (a) attachment mechanisms: vacuum pumps with suction cups (SC) or electromagnets (EM), and (b) joints: electromechanical rotary servomotors. Finally, to validate the numerical approach of MBD-ILAR, we performed an influence study of model parameters: link's length, link's mass, and gravity on the behavior of the attachment forces to the ground, torque, and mechanical power. The future method's application is expected to be useful to complete the phase of the computational robotic design before the physically mechatronic implementation; in addition, it could be adapted to other arthropods.

Celebrating a scientist: Josué A. Núñez’s passion for insect physiology, engineering and evolution

On the tenth anniversary of his passing and the hundredth anniversary of his birth, this article honours Josué A. Núñez (1924–2014), a pioneering Argentine biologist remembered for his groundbreaking work in insect physiology and behaviour. Núñez’s seminal papers are recognized for their rigorous experimentation and his skill in crafting instruments. Known for his humility and sense of humour, he taught and conducted research at prestigious institutions worldwide. The article traces Núñez’s career through key milestones, beginning with his foundational studies in insect anatomy and physiology. It then explores his formative years in Buenos Aires, where he conducted innovative independent experiments, and his influential early career research in Germany. Núñez’s initial interest in the relationship between flowers and honeybees developed into a profound exploration at the intersection of biology, evolutionary theory, and engineering principles. A major focus of this tribute is his integration of engineering concepts to examine the roles of honeybees as both nectar carriers and information channels. By emphasizing Núñez’s meticulous data analysis and systemic approach, the article not only highlights his significant contributions but also challenges traditional Eurocentric perspectives, advocating for a more inclusive understanding of global scientific achievements.

Revealing the larval anatomy of the hoverfly Sphaerophoria rueppellii (Wiedemann, 1820) (Diptera, Syrphidae) using micro-computed tomography

Micro-computed tomography (micro-CT) is an X-ray-based technique that allows visualisation of the internal anatomy of insects in situ and does not require dissections. Traditionally, the study of insect anatomy has been mainly based on dissection techniques and microtome sections. However, micro-CT is becoming an increasingly widespread study technique. We report the use of micro-CT scans to study, in detail, the external and internal structures and organs of the third instar larva of the dipteran Syrphidae Sphaerophoria rueppellii, a Palaearctic species included in the list of effective agents used in European biocontrol programmes against aphids. Detailed images and videos provided evidence of the external morphological characteristics and an overview of the internal anatomy (musculature, digestive tube, salivary glands, Malpighian tubules, fat body, circulatory system, nervous system, cephalopharyngeal complex, tentorium, and mouth parts). The study evidenced the following: an external lateroventral complex of muscles that form muscular rings that allow the compression of the body segments in a similar functional way as occurs in annelid worms; the existence of mandibles with prosthecae; the nervous system present a conspicuous distinguishable suboesophageal ganglion; the so-called antennomaxillary organs are the antennae; the maxillae are separate structures, with an articulated maxillary palpus; S. rueppellii has only one pair of Malpighian tubules instead of the two pairs that were thought to be the general rule for Syrphid larvae; and the evidence of an imaginal disc of genitalia in the posterior part of the body, below the rectum, which in male larvae has a clear correspondence with the morphology of the external male genitalia, which allows to differentiate the sexes in the larval stage. This study constitutes a true anatomical atlas of the third instar larvae of S. rueppellii. High-quality rendered images and additional supplementary videos together with a 3D model, suitable for use with mobile devices, are useful tools for future research and teaching aids.

Same rule, different genes: Blimp1 is a pair-rule gene in the milkweed bug Oncopeltus fasciatus.

Morphological features of organismal body plans are often highly conserved within large taxa. For example, segmentation is a shared and defining feature of all insects. Screens in Drosophila identified genes responsible for the development of body segments, including the "pair-rule" genes (PRGs), which subdivide embryos into double-segment units in a previously unexpected pre-patterning step. Here we show that the milkweed bug Oncopeltus fasciatus also uses a pair rule for embryo subdivision but Oncopeltus employs different genes for this process. We identified the gene Blimp1 as an Oncopeltus PRG based on its expression pattern, tested its function with RNA interference and CRISPR-Cas9, and generated the first PR mutant in this species. Although it does not have PR function in Drosophila, like Drosophila PRGs, Blimp1 encodes a transcription factor required for embryonic viability. Thus, pair-rule subdivision of the insect body plan is more highly conserved than the factors mediating this process, suggesting a developmental constraint on this pre-patterning step.

Analysis of impact of limb segment length variations during reinforcement learning in four-legged robot

Crawling robots are becoming increasingly prevalent in both industrial and private applications. Despite their many advantages over other robot types, they have complex movement mechanics. Artificial intelligence can simplify this by reinforcement learning. This process requires configuring the training environment and defining input parameters, including a robot model for movement training. To translate the virtual results into real-world scenarios, a 3D model with appropriate mechanical parameters must be developed.These parameters can vary significantly between multiple mechanical configurations, which will further impact the reinforcement learning process of such a robot. For this reason, it was decided to test which limb configurations would work best in this process. Initially, various kinematic types of walking robots were analysed, drawing on the anatomy of mammals, reptiles, and insects for the biological model. The reptilian model was chosen for its balance of stability, dynamics, and energy efficiency. The article reviews the preparation of robot models and the configuration of the Unity3D development environment using the ML-Agents toolkit. The experiment examined how different limb lengths affect training, resulting in movement algorithms for various quadruped robot configurations using artificial neural networks. Based on the numerical results, the best configuration was the default, with the same length of the tibia as the thigh, achieving a reward function value of 883.9 and an episode length of 245.5. Taking into account the same criteria, the least efficient configuration was definitely the one characterised by the shortest thigh and the longest tibia among those considered. In its case, the reward function reached a value of only 526.2 with an episode lasting 999.0, which means that it never achieved the intended goal.

Unveiling the Wing Shape Variation in Northern Altiplano Ecosystems: The Example of the Butterfly Phulia nymphula Using Geometric Morphometrics

The Andean Altiplano, characterized by its extreme climatic conditions and high levels of biodiversity, provides a unique environment for studying ecological and evolutionary adaptations in insect morphology. Butterflies, due their large wing surface compared to body surface, and wide distribution among a geographical area given the flight capabilities provided by their wings, constitute a good biological model to study morphological adaptations following extreme weathers. This study focuses on Phulia nymphula, a butterfly species widely distributed in the Andes, to evaluate wing shape variation across six localities in the Northern Chilean Altiplano. The geometric morphometrics analysis of 77 specimens from six locations from the Chilean Altiplano (Caquena, Sorapata Lake, Chungará, Casiri Macho Lake, Surire Salt Flat, and Visviri) revealed significant differences in wing shape among populations. According to the presented results, variations are likely influenced by local environmental conditions and selective pressures, suggesting specific adaptations to the microhabitats of the Altiplano. The first three principal components represented 60.92% of the total wing shape variation. The detected morphological differences indicate adaptive divergence among populations, reflecting evolutionary responses to the extreme and fragmented conditions of the Altiplano. This study gives insights into the understanding of how high-altitude species can diversify and adapt through morphological variation, providing evidence of ecological and evolutionary processes shaping biodiversity in extreme environments.

Discovery of a novel ejaculation mechanism in danceflies (Diptera: Empididae), with implications for genital elongation.

Genitalia are known to evolve rapidly and are among the most variable structures in insect morphology, making them a target of active research. However, function and evolutionary significance of internal genital structures remain less well understood. Here, we report the morphology and mechanism of a novel ejaculatory system that has evolved in the dancefly genus Rhamphomyia (Insecta: Diptera: Empididae). Using synchrotron µCT technology, we examined the male genitalia of five dancefly species and identified an ejaculatory system resembling a leverage hydraulic jack, which is thought to have derived from a plunger-like pumping system. This jacking system amplifies the applied muscle power by up to 4.2 times, allowing the system to produce the same pumping power with much smaller muscles. However, the volume of the pumping muscle in the jacking system is comparable to that of the plunger system, indicating a significant increase in ejaculation power in this genus. We hypothesize that the greater pumping power evolved through sexual selection favoring strong ejaculation to rapidly pass semen through a thin and elongated phallus and spermathecal duct.

Revisiting the four Hexapoda classes: Protura as the sister group to all other hexapods

Insects represent the most diverse animal group, yet previous phylogenetic analyses based on morphological and molecular data have failed to agree on the evolutionary relationships of early insects and their six-legged relatives (together constituting the clade Hexapoda). In particular, the phylogenetic positions of the three early-diverging hexapod lineages-the coneheads (Protura), springtails (Collembola), and two-pronged bristletails (Diplura)-have been debated for over a century, with alternative topologies implying drastically different scenarios of the evolution of the insect body plan and hexapod terrestrialization. We addressed this issue by sampling all hexapod orders and experimenting with a broad range of across-site compositional heterogeneous models designed to tackle ancient divergences. Our analyses support Protura as the earliest-diverging hexapod lineage ("Protura-sister") and Collembola as a sister group to Diplura, a clade corresponding to the original composition of Entognatha, and characterized by the shared possession of internal muscles in the antennal flagellum. The previously recognized 'Elliplura' hypothesis is recovered only under the site-homogeneous substitution models with partial supermatrices. Our cross-validation analysis shows that the site-heterogeneous CAT-GTR model, which recovers "Protura-sister," fits significantly better than homogeneous models. Furthermore, the morphologically unusual Protura are also supported as the earliest-diverging hexapod lineage by other lines of evidence, such as mitogenomes, comparative embryology, and sperm morphology, which produced results similar to those in this study. Our backbone phylogeny of hexapods will facilitate the exploration of the underpinnings of hexapod terrestrialization and megadiversity.

EntomonVR: A new virtual reality game for learning insect morphology

EntomonVR: A new virtual reality game for learning insect morphology

Identification, morphology, and nutrient composition of edible fungi and insects in Myanmar

Identification, morphology, and nutrient composition of edible fungi and insects in Myanmar

Body plan evolvability: The role of variability in gene regulatory networks.

Recent computational modeling of early fruit fly (Drosophila) development has characterized the degree to which gene regulation networks can be robust to natural variability. In the first few hours of development, broad spatial gradients of maternally derived transcription factors activate embryonic gap genes. These gap patterns determine the subsequent segmented insect body plan through pair-rule gene expression. Gap genes are expressed with greater spatial precision than the maternal patterns. Computational modeling of the gap-gap regulatory interactions provides a mechanistic understanding for this robustness to maternal variability in wild-type (WT) patterning. A long-standing question in evolutionary biology has been how a system which is robust, such as the developmental program creating any particular species' body plan, is also evolvable, i.e. how can a system evolve or speciate, if the WT form is strongly buffered and protected? In the present work, we use the WT model to explore the breakdown of such Waddington-type 'canalization'. What levels of variability will push the system out of the WT form; are there particular pathways in the gene regulatory mechanism which are more susceptible to losing the WT form; and when robustness is lost, what types of forms are most likely to occur (i.e. what forms lie near the WT)? Manipulating maternal effects in several different pathways, we find a common gap 'peak-to-step' pattern transition in the loss of WT.We discuss these results in terms of the evolvability of insect segmentation, and in terms of experimental perturbations and mutations which could test the model predictions. We conclude by discussing the prospects for using continuum models of pattern dynamics to investigate a wider range of evo-devo problems.

Morfologi Serangga Yang Tertarik Pada Perangkap Warna di Perkebunan Cabai Merah Desa Pedu Kecamatan Jejawi Kabupaten OKI

Research on the morphology of insects attracted to color traps was carried out in April-June 2023, aiming to study the interest of insects to color and their morphology in red chili plantations, Pedu Village, Jejawi Sub-district, OKI District. This study used a survey method. Sampling by purposive sampling. The color traps used are red, yellow, green and blue. The observation parameter is the number of trapped insect species. Many insects are housed both in the number of species and in the number of individuals of each species. The results of the study found 11 insect species namely, Bactrocera dorsalis, Epilachna sp, Periplanetta americana, Bemisia tabaci, Nezara viridula, Valanga nigriconis, Odontomachus sp., Musca domestica, Agelastica alni, Oxya chinensis, Polistes sp. scattered in red 8 species, yellow 8 species, green 8 species, and blue 1 species. Mouth morphology types include chewing, sucking, piercing-sucking, biting-sucking, and biting-chewing. Head morphology types include hypognathus, prognathus, and opistrorincus types. Antenna morphology types include filiform, clavate, pectinate, aristale, and geniculate types. Wing morphology types include membrane, elytra, halter, and tegmina types. The morphological types of insect violations include cursorial, saltatorial, raptatorial, and natatorial types. 81% of pests, 9% of saprophagus and 9% of pollinators get the role of insects.

Comparison Efficacy of VGG16 and VGG19 Insect Classification Models

This study compares two popular deep-learning models, VGG16 and VGG19, for insect classification. This study aims to evaluate insect detection architectures to automate insect identification. We use a large, heterogeneous dataset of insect species, including common pests and beneficial insects, and their images to achieve this goal. The dataset was used to re-adjust the VGG16 and VGG19 models and analyze their classification performance. With an average improvement of 1,8%, VGG19 outperforms VGG16 in insect classification accuracy. VGG19 is more robust because it can handle complex traits and subtle insect morphology differences. Each architecture's model training duration and computational resources are examined for their practicality in real-world scenarios. This study emphasizes deep learning models in insect classification and shows VGG19's higher accuracy and robustness than VGG16. These findings matter to entomologists, agricultural researchers, and pest control experts. They can improve insect identification accuracy and effectiveness using VGG19-based models, which can help solve insect-related problems in various fields.96.28 percent accuracy was achieved with the implementation of VGG16, according to the experimental findings; 97.07 percent accuracy was obtained with the implementation of VGG19.

Scale insect (Hemiptera: Coccomorpha) morphology is transformed under trophobiosis

Abstract Ants (Hymenoptera: Formicidae) have great potential to exert influence over the morphological evolution of their obligate mutualist partners. Obligately myrmecophilic mealybugs are noted for their unusual morphology, and while this is often attributed to their relationship with ants, a quantitative assessment of this link is lacking. We address this need by evaluating morphological change among mealybugs as a function of ant association. This study considers the associates of 2 independent ant clades—Acropyga Roger, 1862 ants associated with root mealybugs from the families Xenococcidae and Rhizoecidae and herdsmen ants from the Dolichoderus cuspidatus (Smith, F., 1857) species-group associated with mealybugs from the tribe Allomyrmococcini (Pseudococcidae)—and compares them to free-living or potentially myrmecophilic species sampled from among the mealybugs and root mealybugs. We use a combination of geometric morphometric and linear datasets to evaluate characteristics of body shape, body size, leg metrics, and ostiole development. Obligate myrmecophily significantly influences both body shape and size. Myrmecophilous mealybugs are smaller than their free-living counterparts and are either pyriform or rotund in shape rather than oval. Ant-associates from Rhizoecidae also have significantly reduced anterior pairs of ostioles compared to free-living species. Ostioles are involved in defense against natural enemies and mutualist ants typically protect their partners, presumably supplanting the need for structures like ostioles among myrmecophilous species. We discuss the influence ants have on the evolution of their associates in the context of domestication and offer avenues for future exploration.

A review on the effects of heavy metals on the development of blow flies (Diptera: Calliphoridae)

AbstractHeavy metals such as lead, cadmium, zinc, copper, mercury, and others, are naturally occurring non degradable elements which can accumulate in the environment and in living organisms and can have a significant impact on their physiological functions. Studies have shown that heavy metals can also influence the development and morphology of insects. Insects are the most abundant organisms on earth and play a major role in different ecosystems. They help in the dispersion of organic matter and are an important part of different ecological processes. Forensic entomology focuses on the use of arthropods in legal investigations. Shortly after death, a corpse is quickly colonized by several insect families; blow flies (Diptera: Calliphoridae) are among the first colonizers and are therefore often used for the estimation of the time of colonization (TOC) or minimum post‐mortem interval (mPMI). Since larvae feed on the corpse, any xenobiotic present in the remains, including heavy metals, can be ingested, and accumulated by them; these substances can influence their development and, in turn, can alter the estimation of the mPMI. We analyzed the literature on studies pertaining to the detection of heavy metals in blow flies and on their variations in developmental rate, mass, length, fecundity, morphology, immune system, and mortality rate.This article is categorized under: Forensic Biology > Forensic Entomology Forensic Anthropology > Time Since Death Estimation Forensic Biology > Interpretation of Biological Evidence

The Atlas of Death

In a number of works of art, I have taken an interest in insects, bookworms that eat books, electronics as anatomy and clever robots whose actions in a way resemble the apparently primitive abilities of insects. This text has its starting point in two works of art, Eaten Books and Atlas of AInsects. In the artworks, I am interested in insect anatomy and insects as symbols of decay, survival, extinction, death and post humanity. The text is originally from an artistic lecture about my work with insects and coding, and is based on a reading from within the computer program Eaten Books. A performance where the software is letting insects erase the text.

Front Cover: Automated segmentation of insect anatomy from micro‐CT images using deep learning

Front Cover: Automated segmentation of insect anatomy from micro‐CT images using deep learning

Automated segmentation of insect anatomy from micro‐CT images using deep learning

AbstractThree‐dimensional (3D) imaging, such as microcomputed tomography (micro‐CT), is increasingly being used by organismal biologists for precise and comprehensive anatomical characterization. However, the segmentation of anatomical structures remains a bottleneck in research, often requiring tedious manual work. Here, we propose a pipeline for the fully automated segmentation of anatomical structures in micro‐CT images utilizing state‐of‐the‐art deep learning methods, selecting the ant brain as a test case. We implemented the U‐Net architecture for two‐dimensional (2D) image segmentation for our convolutional neural network (CNN), combined with pixel‐island detection. For training and validation of the network, we assembled a data set of semimanually segmented brain images of 76 ant species. The trained network predicted the brain area in ant images fast and accurately; its performance tested on validation sets showed good agreement between the prediction and the target, scoring 80% Intersection over Union (IoU) and 90% Dice Coefficient (F1) accuracy. While manual segmentation usually takes many hours for each brain, the trained network takes only a few minutes. Furthermore, our network is generalizable for segmenting the whole neural system in full‐body scans, and works in tests on distantly related and morphologically divergent insects (e.g., fruit flies). The latter suggests that methods like the one presented here generally apply across diverse taxa. Our method makes the construction of segmented maps and the morphological quantification of different species more efficient and scalable to large data sets, a step toward a big data approach to organismal anatomy.Key points Development of a deep learning‐based pipeline for the fully automated segmentation of micro‐CT images of insects, using ant brains as a starting point. Creation of an open access data set of micro‐CT images of ant heads for training and testing. Generalizable computer vision methodology, extendable across diverse taxa and anatomical features.

Plastic brain structure changes associated with the division of labor and aging in termites.

Division of labor is a prominent feature of social insect societies, where different castes engage in different specialized tasks. As brain differences are associated with behavioral differences, brain anatomy may be linked to caste polymorphism. Here, we show that termite brain morphology changes markedly with caste differentiation and age in the termite, Reticulitermes speratus. Brain morphology was shown to be associated with reproductive division of labor, with reproductive individuals (alates and neotenic reproductives) having larger brains than nonreproductives (workers and soldiers). Micro-computed tomography (CT) imaging and dissection observations showed that the king's brain morphology changed markedly with shrinkage of the optic lobes during their long life in the dark. Behavioral experiments showed that mature primary kings lose visual function as a result of optic lobe shrinkage. These results suggested that termites restructure their nervous systems to perform necessary tasks as they undergo caste differentiation, and that they also show flexible changes in brain morphology even after the final molt. This study showed that brain morphology in social insects is linked to caste and aging, and that the evolution of the division of labor is underpinned by the development of diverse neural systems for specialized tasks.

Inventory of Warehouse Pests on Grain Samples at the Plant Quarantine Laboratory of the Makassar Agricultural Quarantine Center

This study aims to determine and record the types of warehouse pest insects found in several export grain commodities in the plant quarantine laboratory of the Makassar Agricultural Quarantine Center. Data on the types of warehouse pest insects on several grain commodities were obtained by sampling as much as 2 kg from each commodity. Grain commodities are taken in warehouses: rice, corn, green beans, coffee, and cocoa. Then take insects found on the surface or inside the grain. The types of warehouse pest insects found in grain samples were identified based on insect morphology. Then secondary data related to kinship relationships between insect species and data on optimal environmental factors for insect growth are taken from book and journal references. The number of warehouse pest insects found in several export grain commodities in the plant quarantine laboratory of BBPK Makassar is eight types. Insect pests are only found in rice, corn, and cocoa commodities. Types of insect pests found, namely <em>Sitophilus oryzae</em>, <em>Sitophilus zeamais</em>, <em>Tribolium castaneum</em>, <em>Cryptolestes ferrugineus</em>, <em>Araecerus fasciculatus</em>, <em>Ahasverus advena</em>, <em>Ephestia kuehniella,</em> and <em>Sitotroga cerealella</em>.