Friedrich G. Barth

Biomaterial systems for mechanosensing and actuation.

Living organisms use composite materials for various functions, such as mechanical support, protection, motility and the sensing of signals. Although the individual components of these materials may have poor mechanical qualities, they form composites of polymers and minerals with a remarkable variety of functional properties. Researchers are now using these natural systems as models for artificial mechanosensors and actuators, through studying both natural structures and their interactions with the environment. In addition to inspiring the design of new materials, analysis of natural structures on this basis can provide insight into evolutionary constraints on structure–function relationships in living organisms and the variety of structural solutions that emerged from these constraints.

Neurobiology of arachnids.

A The Central Nervous System: Structure and Development.- I Patterns of Arrangement and Connectivity in the Central Nervous System of Arachnids.- II Ontogeny of the Arachnid Central Nervous System.- III The Stomatogastric Nervous System and Neurosecretion.- B Structure and Function of Sensory Systems.- Vision.- IV The Morphology and Optics of Spider Eyes.- V The Fine Structure of Spider Photoreceptors in Relation to Function.- VI Photoreceptor Cells in the Spider Eye: Spectral Sensitivity and Efferent Control.- Mechano- and Chemoreception.- VII Mechano- and Chemoreceptive Sensilla.- VIII Trichobothria.- IX Slit Sensilla and the Measurement of Cuticular Strains.- Sensory Nerves and Peripheral Synapses.- X Sensory Nerves and Peripheral Synapses.- C Senses and Behavior.- XI Neuroethology of the Spider Vibration Sense.- XII Spider Proprioception: Receptors, Reflexes, and Control of Locomotion.- XIII Target Discrimination in Jumping Spiders (Araneae: Salticidae).- XIV Homing Behavior and Orientation in the Funnel-Web Spider, Agelena labyrinthica Clerck.- XV Analytical Cybernetics of Spider Navigation.- D The Motor System.- XVI Neural Control of the Heartbeat and Skeletal Muscle in Spiders and Scorpions.- XVII Central and Peripheral Organization of Scorpion Locomotion.- E Neurobiology of a Biological Clock.- XVIII Neurobiology of a Circadian Clock in the Visual System of Scorpions.

Sensors and sensing in biology and engineering

INTRODUCTORY REMARKS Sensors and sensing: a biologists view (F. G. Barth), Sensors and sensing: an engineers view (H. Meixner) MECHANICAL SENSORS Waves, Sound and Vibrations How nature designs ears (A. Michelsen), How to build a microphone (P. Rasmussen), The middle and external ears of terrestrial vertebrates as mechanical and acoustic transducers (J. J Rosowski), The outer hair cell: a mechanoelectrical and electromechanical sensor/actuator (K.V. Snyder, F. Sachs, W. E. Brownell), The silicon cochlea (R. Sarpeshkar), Biologically-inspired microfabricated force and position mechano-sensors (P. Dario et al.) Force and Motion The physics of arthropod medium-flow sensitive hairs: biological models for artificial sensors (J. A. C. Humphrey, F. G. Barth, M. Reed, A. Spak), Cricket wind receptors: thermal noise for the highest sensitivity known (T. Shimozawa, J. Murakami, T. Kumagai), Arthropod cuticular hairs: tactile sensors and the refinement of stimulus transformation (F. G. Barth, H.-E. Dechant), The fish lateral line: how to detect hydrodynamic stimuli (J. Mogdans, J. Engelmann, W. Hanke, S. Krother), The blood vasculature as an adaptive system: role of mechanical sensing (T. W. Secomb, A. R. Pries), Mechanism of shear stress-induced coronary microvascular dilation (L. Kuo, T. W. Hein), A possible mechanism for sensing crop canopy ventilation (T. Farquhar, J. Zhou, H. W. Haslach Jr.) VISUAL SENSORS AND VISION From fly vision to robot vision: re-construction as a mode of discovery (N. Franceschini), Locusts looming detectors for robot sensors (F. C. Rind, R. D. Santer, J. M. Blanchard, P. F. M. J. Verschure), Retina-like sensors: motivations, technology and applications (G. Sandini, G. Metta), Computing in cortical columns: information processing in visual cortex (S. W. Zucker), Vision by graph pyramids (W.G. Kropatsch) CHEMOSENSORS AND CHEMOSENSING Mechanisms for gradient following (D.B. Dusenbery), Representation of odor information in theolfactory system: from biology to an artificial nose (J. S. Kauer, J. White), The external aerodynamics of canine olfaction (G. S. Settles, D.A. Kester, L.J. Dodson-Dreibelbis), Microcantilevers for physical, chemical, and biological sensing (T. Thundat, A. Majumdar) THE EMBEDDING OF SENSORS Embedded mechanical sensors in artificial and biological systems (P. Calvert), Active dressware: wearable kinesthetic systems (D. de Rossi, F. Lorussi, A. Mazzoldi, P. Orsini, E. P. Scilingo)

Ein atlas der spaltsinnesorgane von Cupiennius salei keys. Chelicerata (Araneae)

To facilitate further physiological investigation, a survey was undertaken of all the slit sense organs to be found on the body of the spider Cupiennius salei. We counted and mapped more than 3 000 sensory slits in the cuticle about half of which are combined to small groups of up to 29 slits forming compound or lyriform organs.

Vibratory Communication Through Living Plants by a Tropical Wandering Spider

Female Cupiennius salei pheromone on banana and Agave plants elicits patterned oscillations by the male. Resulting pulse trains of vibrations through the leaf average 76 hertz. The brief vibratory response by the otherwise immobile female hidden up to at least 1 meter away on another leaf guides the male across the plant to her location. Reciprocal signaling continues in the presence of random noise that masks the males airborne sounds.

Compound slit sense organs on the spider leg: Mechanoreceptors involved in kinesthetic orientation

Summary1.The hunting spiderCupiennius salei Keys is able to direct its locomotion by making use of information about its own previous movement sequences (kinesthetic orientation). After a blinded spider is chased ca. 25 cm away from a prey-fly, it returns to the original capture site despite the preclusion of other possible orientation clues. The mean starting direction of such returns differs from the ideal return direction by only 2 ° (Fig. 4a, 5). Of all runs 95% are “successful” in that the animals approach the capture site as close as 5 cm (mean value) (Fig. 3).2.Mechanical destruction of compound slit sense (“lyriform”) organs on femur and tibia of all legs results in disorientation of the spiders: more than 2/3 of their returns pass the capture site at a distance of more than 10 cm (Fig. 3, 4b). In addition, the mean angular deviation of starting directions increases significantly. The difference between the mean starting angles of the treated groups and the mean of intact animals, however, is significant only in some cases.3.A special effort was made to evaluate not only thestarting directions and the “success” of a return path, but theentire return route, which is comprised of several path segments based upon each stopping and/or turning point. To this end a “walking error” en was determined for each segment (Fig. 8). For intact animals the error increases abruptly at the point nearest to the capture site. We therefore conclude that the spiders control also their walking distance kinesthetically. In the case of operated animals the mean “walking error” calculated from those segments lying before the “nearest point” increases by a factor of 4 to 5, as compared with intact spiders, whereas it remains about the sameat the “nearest point” itself (Fig. 9).4.Small holes pierced into the leg cuticle near intact lyriform organs of otherwise intact “control animals” do not influence the success, starting angle, and walking errors of returns.

Ecology of Sensing

General Aspects.- Sound and Hearing.- Medium Flow and Vibrations.- Light and Vision.- Odor and Chemoreception.- Hygro- and Thermoreception.- Magnetic Field and Electroreception

Der sensorische Apparat der Spaltsinnesorgane (Cupiennius salei Keys., Araneae)

SummaryA large single slit sense organ on the tarsus of the spider Cupiennius salei Keys, was examined electronmicroscopically and compared with a small single slit sense organ also on the tarsus and with the compound (lyriform) organ on the metatarsus.1.The so-called slit consists of two parts. The upper one is a trough-shaped chamber in the exocuticle, flat at both ends of its longitudinal axis and growing deeper towards its mid-portion until only a floor remains 0.23 μm thick (inner membrane of the slit = M.i.). The exocuticle thickens around the slit into a reinforcing frame with specific arrangement of the exocuticular lamellae. The lower part opens out from M.i. like a bell into the meso- and endocuticle.2.The trough-shaped upper chamber is covered by a membrane 0.25 μm thick (outer membrane of the slit = M.a.). The main component of this membrane resembles the “dense layer” of the epicuticle.3.The slit is innervated by two dendrites. One of them ends close to M.i. The other passes through an opening of M.i. and runs up to M. a.4.Both dendrites are composed of three portions markedly different in fine structure. a) The portion close to the soma contains tubules and a modest number of mitochondria. b) More distally a pronounced swelling of the dendrite follows, rich in mitochondria but lacking tubules. c) The most distal part begins with a ciliary configuration of microtubules. Its basal bodies are located in the dendritic swelling. This part does not contain any mitochondria but numerous tubules with a network of electron dense material between them.5.Distal to their ciliary segments both dendrites are surrounded by a common sheath of high electron density.6.Viewed from above a slight, flat, tear-shaped depression can be seen in M.a. Towards its middle the depression deepens to form a cylinder (ø 0.5 μm, depth 1 μm). The end of the longer dendrite penetrates the floor of this cylinder and projects like a finger into its interior. About 0.7 μm proximal and distal to the dendrite — M.a. junction, electron dense material accumulates around and within the dendrite (tubular body).7.Two sheath cells surround both dendrites in common. The inner cell terminates at the level of the ciliary structure. The outer cell continues more distally towards M.i. The apical part of the outer sheath cell forms a large invagination bordered by a microvillous cell membrane and an extracellular layer of medium electron density. A substance very similar or identical with that of the layer is found deeper within the leg in a spaceous lacunar system formed by further cell invaginations and extended extracellular gaps.8.The fine structure of the input apparatus of a small single slit on the tarsus and the compound lyriform organ on the metatarsus is essentially the same as that of the large single tarsal slit.ZusammenfassungEin großes Einzelspaltsinnesorgan auf dem Tarsus der Spinne Cupienniua salei Keys. wird elektronenmikroskopisch untersucht und mit einem kleinen tarsalen Einzelorgan sowie dem zusammengsetzten (lyriformen) Organ des Metatarsus verglichen.1.Der sog. Spalt besteht aus zwei Anteilen: a) Der in der Exocuticula gelegene hat die Gestalt einer Rinne (Länge ca. 51 μm, Breite ca. 2,2 μm), welche an den Enden ihrer Längserstreckung flach ist und in einer Mittelzone die Exocuticula bis auf einen ca. 0,23 μm starken Boden (innere Membran = M.i.) durchstößt. Die Exocuticula bildet um den Spalt herum einen verstärkenden Rahmen mit spezifischer Anordnung der exocuticularen Lamellen. b) Der in Meso- und Endocuticula gelegene Anteil öffnet sich von M. i. aus glockenförmig zur Epidermis hin.2.Der Spalt ist überall von einer ca. 0,25 μm dicken Membran (äußere Membran M.a.) bedeckt, deren quantitativ wichtigste Komponente elektronenoptisch der innersten Lage der Epicuticula (dense layer) gleicht.3.Das Spaltsinnesorgan wird von zwei Dendriten innerviert. Während einer davon nahe M.i. endet, zieht der andere durch eine Öffnung in dieser bis zu M. a.4.Beide Dendrite weisen dieselbe feinstrukturelle Dreigliederung auf. a) Der dem Zellsoma folgende Abschnitt enthält Tubuli und einige randständige Mitochondrien. b) Nach distal folgt eine mitochondrienreiche und tubuluslose Dendritenanschwellung. c) Der somafernste Abschnitt beginnt mit einer Ciliarstruktur, deren Basalkörper in der Anschwellung liegen. Er zeichnet sich durch zahlreiche von periodischen Querstrukturen miteinander verbundene Tubuli sowie das vollkommene Fehlen von Mitochondrien aus.5.Distal von der Ciliarstruktur umgibt eine gemeinsame elektronendichte Scheide die beiden Dendrite.6.In der Mittelzone ihrer Längserstreckung bildet M.a. an einem in der Aufsicht tropfenförmigen und leicht versenkten Flächenausschnitt eine zylinderförmige Vertiefung (Tiefe ca. 1 μm, ø ca. 0,5 μm) aus, durch deren Boden der längere Dendrit samt Scheide hindurchzieht, um als fingerförmige Erhebung in dem Zylinder zu enden. Das Ende dieses Dendriten zeichnet sich durch eine extra- und intrazelluläre Ansammlung elektronendichter Substanz aus (Tubularkörper).7.Eine innere und eine äußere Hüllzelle (Hz 1 bzw. Hz 2) umgeben die Dendrite gemeinsam. Hz 1 endet distal auf Höhe der Ciliarkörper, Hz 2 reicht nahe bis zu M.i. Der apikale Bereich von Hz 2 bildet eine große, nach distal offene Invagination aus, welche von Mikrovilli und einer daraufliegenden extrazellulären Substanz gesäumt wird. Elektronenoptisch vergleichbares Material findet sich in einem ausgedehnten Lakunensystem, das weiter proximal von weiteren Zellinvaginationen und erweiterten Extrazellularräumen gebildet wird.8.Der sensorische Apparat eines kleinen tarsalen Einzelorgans sowie des metatarsalen lyriformen Organs stimmt im wesentlichen mit dem des großen tarsalen Einzelspalts überein.

Vibrations in the orb web of the spider Nephila clavipes: cues for discrimination and orientation

Transmission of natural and artificial vibrations in webs of Nephila clavipes was examined using laser Doppler vibrometry to determine how this spider discriminates and localizes stimuli. 1. Vibration signals of four entrapped insect species peaked at different frequencies from 5–30 Hz, but their spectra overlapped considerably. Peak amplitudes spanned 50 dB. 2. Transmission of longitudinal vibrations along individual radii was attenuated over ca. 12 cm by 4.0 ± 2.7 dB; attenuation values for transverse and lateral vibrations were 22.2 ± 4.6 dB and 26.2 ± 4.3 dB, respectively. Some transmission spectra characteristics may be explained by “resonances” of the spider and threads. 3. Radial thread transmission increased by 2.2–5.8 dB after cutting the connecting auxiliary spirals, demonstrating that vibrations “leak” from stimulated radii via these threads. Auxiliary spirals provide structural support to Nephila webs at the expense of degraded directional transmission. 4. Upon single-point stimulation, vibrations measured around the web hub and at the spiders tarsi revealed 2-D vibration amplitude “gradients” of 20–30 dB indicating the stimulus direction. In contrast, measured vibration propagation velocities of 70–1500 m/s resulted in time-of-arrival differences at the spiders tarsi of < 1.5 ms, which may be too brief for stimulus direction determination.

Idiothetic orientation of a wandering spider: Compensation of detours and estimates of goal distance

SummaryThe wandering spider Cupiennius salei Keys uses idiothetic orientation, i.e., memorized information about its own previous movements, to retrieve lost prey. Spiders, having been chased away from a prey fly, return to the capture site (the goal) over a distance of more than 75 cm even though all external orientation cues were precluded. This behavior and its sensory basis were examined by varying the proprioceptive and ‘motor command’ inputs to the memory and by ablating particular lyriform slit sense organs on the legs of the spider.The success rate of returns to the goal after rectilinear chases over 6 discrete distances ranging from 20 cm to>41 cm declines with increasing distances. At distances>41 cm, more than 50% of the performances of intact spiders are nevertheless ‘successful’, in that the animals approach the capture site as close as 5 cm (or less).Animals that have been operated on (lyriform organs on all femora destroyed) are much less successful even at short distances. The mean starting angles of the returns by intact spiders and by those operated on do not differ signficantly. ‘Walking error en’ for each segment of the entire return path shows that intact animals deviate little from the ideal return route and correctly estimate the distance to the goal. The operated spiders tend to drift off the ideal return route, while their distance estimates remain largely accurate.Returns after curvilinear chases through a semicircular corridor do not retrace the curved path; instead the spiders take a shortcut. Of all performances by intact and by control spiders (with sham operations) 85% are successful. By contrast, most of the 8 groups with sensory ablations have a success rate of less than 50%.Compensation for the semicircular detours is not quite complete: the mean starting directions of returns are biased, pointing to the corridor, and the shape of many return paths reflects the curved corridor shape. Spiders with unilateral ablations of their femoral lyriform organs show low success rates only if the operated legs are on the inner curve perimeter during the chase, while their return parameters resemble those of the intact group in the reverse situation (operated legs on outer perimeter). These side-specific ablation effects, which are correlated with the geometrical situation existing while idiothetic information is gathered and memorized, suggest that the idiothetic memory depends at least partly on input from proprioceptors.