Biomechanical components of the plant-insect herbivore arms race: a model test in leaf-cutter ants.

Insects and plants have been locked in an evolutionary arms race spanning 350 million years. Insects evolved specialized tools to cut into plant tissue, and plants, to counter these attacks, developed diverse defence strategies. Much previous worked has focused on chemical defences.

Superefficient teamwork in weaver ants.

Teamwork is often assumed to enhance group performance, particularly for physical tasks. However, in both human and non-human animal teams, the effort contributed by each member may, in fact, decrease as team size grows. This counterintuitive phenomenon, known as the Ringelmann effect, is generally ascribed to poor coordination or differences in motivation.

The role of the membrane in the hen's egg as a model for increasing the toughness of engineered brittle materials.

Eggshell and the attached membrane are the focus of many fields of research, but their mechanical properties as a biomineralised composite are seldom explored. This investigation aimed to asses the influence of the membrane on energy dissipation during macroscopic structure failure, and if this effect could be reproduced with artificial membranes for later use in biomimetic materials. Compression tests followed by fracture pattern analysis were conducted for five types of manipulated egg halves: samples with and without the natural membrane, and three samples where the membrane was replaced with artificial membranes made from epoxy resin, polyurethane resin, or wood glue.

Behavioural biomechanics: leaf-cutter ant cutting behaviour depends on leaf edge geometry.

Leaf-cutter ants cut fresh leaves to grow a symbiotic fungus as crop. During cutting, one mandible is typically anchored onto the leaf lamina while the other slices through it like a knife. When initiating cuts into the leaf edge, however, foragers sometimes deviate from this behaviour and instead use their mandibles symmetrically, akin to scissors.

Iron-coated Komodo dragon teeth and the complex dental enamel of carnivorous reptiles.

Komodo dragons (Varanus komodoensis) are the largest extant predatory lizards and their ziphodont (serrated, curved and blade-shaped) teeth make them valuable analogues for studying tooth structure, function and comparing with extinct ziphodont taxa, such as theropod dinosaurs. Like other ziphodont reptiles, V. komodoensis teeth possess only a thin coating of enamel that is nevertheless able to cope with the demands of their puncture-pull feeding.

Optimal Gearing of Musculoskeletal Systems.

Movement is integral to animal life, and most animal movement is actuated by the same engine: striated muscle. Muscle input is typically mediated by skeletal elements, resulting in musculoskeletal systems that are geared: at any instant, the muscle force and velocity are related to the output force and velocity only via a proportionality constant G, the "mechanical advantage". The functional analysis of such "simple machines" has traditionally centered around this instantaneous interpretation, such that a small vs large G is thought to reflect a fast vs forceful system, respectively.

Understanding Trophic Interactions in a Warming World by Bridging Foraging Ecology and Biomechanics with Network Science.

Climate change will disrupt biological processes at every scale. Ecosystem functions and services vital to ecological resilience are set to shift, with consequences for how we manage land, natural resources, and food systems. Increasing temperatures cause morphological shifts, with concomitant implications for biomechanical performance metrics crucial to trophic interactions.

The effect of muscle ultrastructure on the force, displacement and work capacity of skeletal muscle.

Skeletal muscle powers animal movement through interactions between the contractile proteins, actin and myosin. Structural variation contributes greatly to the variation in mechanical performance observed across muscles. In vertebrates, gross structural variation occurs in the form of changes in the muscle cross-sectional area : fibre length ratio.

Large deformation diffeomorphic mapping of 3D shape variation reveals two distinct mandible and head capsule morphs in leaf-cutter worker ants.

Ants are crucial ecosystem engineers, and their ecological success is facilitated by a division of labour among sterile "workers". In some ant lineages, workers have undergone further morphological differentiation, resulting in differences in body size, shape, or both. Distinguishing between changes in size and shape is not trivial.

replicAnt: a pipeline for generating annotated images of animals in complex environments using Unreal Engine.

Deep learning-based computer vision methods are transforming animal behavioural research. Transfer learning has enabled work in non-model species, but still requires hand-annotation of example footage, and is only performant in well-defined conditions. To help overcome these limitations, we developed replicAnt, a configurable pipeline implemented in Unreal Engine 5 and Python, designed to generate large and variable training datasets on consumer-grade hardware.

Three-dimensional kinematics of leaf-cutter ant mandibles: not all dicondylic joints are simple hinges.

Insects use their mandibles for a variety of tasks, including food processing, material transport, nest building, brood care, and fighting. Despite this functional diversity, mandible motion is typically thought to be constrained to rotation about a single fixed axis. Here, we conduct a direct quantitative test of this 'hinge joint hypothesis' in a species that uses its mandibles for a wide range of tasks: leaf-cutter ants.

Developmental biomechanics and age polyethism in leaf-cutter ants.

Many social insects display age polyethism: young workers stay inside the nest, and only older workers forage. This behavioural transition is accompanied by genetic and physiological changes, but the mechanistic origin of it remains unclear. To investigate if the mechanical demands on the musculoskeletal system effectively prevent young workers from foraging, we studied the biomechanical development of the bite apparatus in leaf-cutter ants.

Strong positive allometry of bite force in leaf-cutter ants increases the range of cuttable plant tissues.

Atta leaf-cutter ants are the prime herbivore in the Neotropics: differently sized foragers harvest plant material to grow a fungus as a crop. Efficient foraging involves complex interactions between worker size, task preferences and plant-fungus suitability; it is, however, ultimately constrained by the ability of differently sized workers to generate forces large enough to cut vegetation. In order to quantify this ability, we measured bite forces of Atta vollenweideri leaf-cutter ants spanning more than one order of magnitude in body mass.

A theory of physiological similarity in muscle-driven motion.

Muscle contraction is the primary source of all animal movement. I show that the maximum mechanical output of such contractions is determined by a characteristic dimensionless number, the "effective inertia," , defined by a small set of mechanical, physiological, and anatomical properties of the interrogated musculoskeletal complex. Different musculoskeletal systems with equal may be considered physiologically similar, in the sense that maximum performance involves equal fractions of the muscle's maximum strain rate, strain capacity, work, and power density.

Multilevel dynamic adjustments of geckos () climbing vertically: head-up versus head-down.

Many climbing animals use direction-dependent adhesives to attach to vertical or inclined surfaces. These structures adhere when activated via a pull but detach when pushed. Therefore, a challenge arises when a change in climbing direction causes external forces such as gravity to change its acting orientation upon the lizard.

A biomechanical model for the relation between bite force and mandibular opening angle in arthropods.

Bite forces play a key role in animal ecology: they affect mating behaviour, fighting success, and the ability to feed. Although feeding habits of arthropods have a significant ecological and economical impact, we lack fundamental knowledge on how the morphology and physiology of their bite apparatus controls bite performance, and its variation with mandible gape. To address this gap, we derived a biomechanical model that characterizes the relationship between bite force and mandibular opening angle from first principles.

The physical properties of the stick insect pad secretion are independent of body size.

Many insects use adhesive organs to climb. The ability to cling to surfaces is advantageous but is increasingly challenged as animals grow, due to the associated reduction in surface-to-volume ratio. Previous work has demonstrated that some climbing animals overcome this scaling problem by systematically altering the maximum force per area that their adhesive pads can sustain; their adhesive organs become more efficient as they grow, an observation which is also of substantial relevance for the design of bioinspired adhesives.

Elastic energy storage and the efficiency of movement.

Movement is an integral part of animal biology. It enables organisms to escape from danger, acquire food, and perform courtship displays. Changing the speed or vertical position of a body requires mechanical energy.

Morphological determinants of bite force capacity in insects: a biomechanical analysis of polymorphic leaf-cutter ants.

The extraordinary success of social insects is partially based on division of labour, i.e. individuals exclusively or preferentially perform specific tasks.

-an open-source platform for the creation of 3D models of arthropods (and other small objects).

We present , an open-source platform for the creation of digital 3D models of arthropods and small objects. consists of a scanner and a Graphical User Interface, and enables the automated generation of Extended Depth Of Field images from multiple perspectives. These images are then masked with a novel automatic routine which combines random forest-based edge-detection, adaptive thresholding and connected component labelling.