Bite force transmission and mandible shape in grasshoppers, crickets, and allies is not driven by dietary niches.

Although species evolve in response to many intrinsic and extrinsic factors, frequently one factor has a dominating influence on a given organ system. In this context, mouthpart shape and function are thought to correlate strongly with dietary niche and this was advocated for decades, e.g.

A leg model based on anatomical landmarks to study 3D joint kinematics of walking in .

Walking is the most common form of how animals move on land. The model organism has become increasingly popular for studying how the nervous system controls behavior in general and walking in particular. Despite recent advances in tracking and modeling leg movements of walking in 3D, there are still gaps in knowledge about the biomechanics of leg joints due to the tiny size of fruit flies.

Linking shape conspicuous asymmetry with shape covariation patterns and performance in the insect head and mandibles.

Bilateral symmetry is widespread across animals, yet, among bilaterians, many cases of conspicuous asymmetries evolved. This means that bilaterally homologous structures on the left and right sides display divergent phenotypes. The evolution of such divergent phenotypes between otherwise similarly shaped structures can be thought to be favored by modularity, but this has rarely been studied in the context of left-right differences.

A bite force database of 654 insect species.

Bite force is a decisive performance trait in animals because it plays a role for numerous life history components such as food consumption, inter- and intraspecific interactions, and reproductive success. Bite force has been studied across a wide range of vertebrate species, but only for 32 species of insects, the most speciose animal lineage. Here we present the insect bite force database with bite force measurements for 654 insect species covering 476 genera, 111 families, and 13 orders with body lengths ranging from 3.

A comparison of dissection and 3D approaches to estimate muscle physiological cross-sectional area, validated by in vivo bite forces.

Performance traits such as bite forces are crucial to fitness and relate to the niche and adaptation of species. However, for many insects it is not possible to directly measure bite forces because they are too small. Biomechanical models of bite forces are therefore relevant to test hypotheses of adaptation in insects and other small organisms.

Ultra high-resolution biomechanics suggest that substructures within insect mechanosensors decisively affect their sensitivity.

Insect load sensors, called campaniform sensilla (CS), measure strain changes within the cuticle of appendages. This mechanotransduction provides the neuromuscular system with feedback for posture and locomotion. Owing to their diverse morphology and arrangement, CS can encode different strain directions.

A previously unknown feeding mode in millipedes and the convergence of fluid feeding across arthropods.

We report fluid feeding with a sucking pump in the arthropod class Diplopoda, using a combination of synchrotron tomography, histology, electron microscopy, and three-dimensional reconstructions. Within the head of nine species of the enigmatic Colobognatha, we found a pumping chamber, which acts as positive displacement pump and is notably similar to that of insects, showing even fine structural convergences. The sucking pump of these millipedes works together with protractible mouthparts and externally secreted saliva for the acquisition of liquid food.

Suspension feeders: diversity, principles of particle separation and biomimetic potential.

Suspension feeders (SFs) evolved a high diversity of mechanisms, sometimes with remarkably convergent morphologies, to retain plankton, detritus and man-made particles with particle sizes ranging from less than 1 µm to several centimetres. Based on an extensive literature review, also including the physical and technical principles of solid-liquid separation, we developed a set of 18 ecological and technical parameters to review 35 taxa of suspension-feeding Metazoa covering the diversity of morphological and functional principles. This includes passive SFs, such as gorgonians or crinoids that use the ambient flow to encounter particles, and sponges, bivalves or baleen whales, which actively create a feeding current.

Ovipositor and mouthparts in a fossil insect support a novel ecological role for early orthopterans in 300 million years old forests.

A high portion of the earliest known insect fauna is composed of the so-called 'lobeattid insects', whose systematic affinities and role as foliage feeders remain debated. We investigated hundreds of samples of a new lobeattid species from the Xiaheyan locality using a combination of photographic techniques, including reflectance transforming imaging, geometric morphometrics, and biomechanics to document its morphology, and infer its phylogenetic position and ecological role. sp.

Juvenile ecology drives adult morphology in two insect orders.

Most animals undergo ecological niche shifts between distinct life phases, but such shifts can result in adaptive conflicts of phenotypic traits. Metamorphosis can reduce these conflicts by breaking up trait correlations, allowing each life phase to independently adapt to its ecological niche. This process is called adaptive decoupling.

Neuromodulation Can Be Simple: Myoinhibitory Peptide, Contained in Dedicated Regulatory Pathways, Is the Only Neurally-Mediated Peptide Modulator of Stick Insect Leg Muscle.

In the best studied cases ( feeding, crustacean stomatogastric system), peptidergic modulation is mediated by large numbers of peptides. Furthermore, in , excitatory motor neurons release the peptides, obligatorily coupling target activation and modulator release. Vertebrate nervous systems typically contain about a hundred peptide modulators.

Four myriapod relatives - but who are sisters? No end to debates on relationships among the four major myriapod subgroups.

Background: Phylogenetic relationships among the myriapod subgroups Chilopoda, Diplopoda, Symphyla and Pauropoda are still not robustly resolved. The first phylogenomic study covering all subgroups resolved phylogenetic relationships congruently to morphological evidence but is in conflict with most previously published phylogenetic trees based on diverse molecular data. Outgroup choice and long-branch attraction effects were stated as possible explanations for these incongruencies.

The loss of flight in ant workers enabled an evolutionary redesign of the thorax for ground labour.

Background: Explanations for the ecological dominance of ants generally focus on the benefits of division of labour and cooperation during foraging. However, the principal innovation of ants relative to their wasp ancestors was the evolution of a new phenotype: a wingless worker caste optimized for ground labour. Ant workers are famous for their ability to lift and carry heavy loads, but we know surprisingly little about the morphological basis of their strength.

Location and arrangement of campaniform sensilla in Drosophila melanogaster.

Sensory systems provide input to motor networks on the state of the body and environment. One such sensory system in insects is the campaniform sensilla (CS), which detect deformations of the exoskeleton arising from resisted movements or external perturbations. When physical strain is applied to the cuticle, CS external structures are compressed, leading to transduction in an internal sensory neuron.

A biological switching valve evolved in the female of a sex-role reversed cave insect to receive multiple seminal packages.

We report a functional switching valve within the female genitalia of the Brazilian cave insect . The valve complex is composed of two plate-like sclerites, a closure element, and in-and-outflow canals. Females have a penis-like intromittent organ to coercively anchor males and obtain voluminous semen.

Analysis of modularity and integration suggests evolution of dragonfly wing venation mainly in response to functional demands.

Insect wings show a high variability in wing venation. Selection for function, developmental pathways and phylogeny likely influenced wing vein diversification, however, quantitative data to estimate these influences and their interplay are missing. Here, it is tested how dragonfly wing vein configuration is influenced by functional demands, development, phylogeny and allometry using the concepts of modularity and integration.

A Dipteran's Novel Sucker Punch: Evolution of Arthropod Atypical Venom with a Neurotoxic Component in Robber Flies (Asilidae, Diptera).

Predatory robber flies (Diptera, Asilidae) have been suspected to be venomous due to their ability to overpower well-defended prey. However, details of their venom composition and toxin arsenal remained unknown. Here, we provide a detailed characterization of the venom system of robber flies through the application of comparative transcriptomics, proteomics and functional morphology.

Age-dependent male mating tactics in a spider mite-A life-history perspective.

Males often fight with rival males for access to females. However, some males display nonfighting tactics such as sneaking, satellite behavior, or female mimicking. When these mating tactics comprise a conditional strategy, they are often thought to be explained by resource holding potential (RHP), that is, nonfighting tactics are displayed by less competitive males who are more likely to lose a fight.

Form-function relationships in dragonfly mandibles under an evolutionary perspective.

Functional requirements may constrain phenotypic diversification or foster it. For insect mouthparts, the quantification of the relationship between shape and function in an evolutionary framework remained largely unexplored. Here, the question of a functional influence on phenotypic diversification for dragonfly mandibles is assessed with a large-scale biomechanical analysis covering nearly all anisopteran families, using finite element analysis in combination with geometric morphometrics.

Evolutionary ecology of beta-lactam gene clusters in animals.

Beta-lactam biosynthesis was thought to occur only in fungi and bacteria, but we recently reported the presence of isopenicillin N synthase in a soil-dwelling animal, Folsomia candida. However, it has remained unclear whether this gene is part of a larger beta-lactam biosynthesis pathway and how widespread the occurrence of penicillin biosynthesis is among animals. Here, we analysed the distribution of beta-lactam biosynthesis genes throughout the animal kingdom and identified a beta-lactam gene cluster in the genome of F.

Computational biomechanics changes our view on insect head evolution.

Despite large-scale molecular attempts, the relationships of the basal winged insect lineages dragonflies, mayflies and neopterans, are still unresolved. Other data sources, such as morphology, suffer from unclear functional dependencies of the structures considered, which might mislead phylogenetic inference. Here, we assess this problem by combining for the first time biomechanics with phylogenetics using two advanced engineering techniques, multibody dynamics analysis and finite-element analysis, to identify functional linkages in insect head structures which have been used traditionally to argue basal winged insect relationships.

Musculoskeletal modelling under an evolutionary perspective: deciphering the role of single muscle regions in closely related insects.

Insects show a remarkable diversity of muscle configurations, yet the factors leading to this functional diversity are poorly understood. Here, we use musculoskeletal modelling to understand the spatio-temporal activity of an insect muscle in several dragonfly species and to reveal potential mechanical factors leading to a particular muscle configuration. Bite characteristics potentially show systematic signal, but absolute bite force is not correlated with size.

Musculoskeletal modelling of the dragonfly mandible system as an aid to understanding the role of single muscles in an evolutionary context.

Insects show a great variety of mouthpart and muscle configurations; however, knowledge of their mouthpart kinematics and muscle activation patterns is fragmentary. Understanding the role of muscle groups during movement and comparing them between insect groups could yield insights into evolutionary patterns and functional constraints. Here, we developed a mathematical inverse dynamic model including distinct muscles for an insect head-mandible-muscle complex based on micro-computed tomography (µCT) data and bite force measurements.