bluuebunny/crossref_metadata_2025_split huggingface dataset:
Which Parameters Control the Leg Movement of A Walking Insect?: I. Velocity Control During the Stance Phase
Authors: Cruse H. 
Published: April 2021

ABSTRACT
In treadwheel walking, the front and middle legs of the stick insect (Carausius morosus) propel the wheel, while the hind legs exert very little force and can even decelerate the wheel. This result is compared with observations on the function of the legs in different walking situations.
Several hypotheses assuming different types of position servo-mechanisms have been proposed in the literature on the control of leg movement during walking in insects. The experimental results support none of these hypotheses. Instead, they indicate that velocity rather than position is the variable controlled during the stance phase.
Plasticity And Proprioception In Insects I. Responses and Cellular Properties of Individual Receptors of the Locust Metathoracic Femoral Chordotonal Organ
Authors: Zill Sasha N. 
Published: April 2021

ABSTRACT
The metathoracic femoral chordotonal organ is a joint angle receptor of the locust hindleg. It consists of 45–55 bipolar sensory neurones located distally in the femur and mechanically coupled to the tibia. Responses of receptors of the organ were examined by extracellular and intracellular recording. The organ as a whole encodes the angle of the femoro-tibial joint but shows substantial hysteresis. Tonic activity is greatest at the extremes of joint position. The organ possesses no direct linkage to tibial muscle fibres and shows no response to resisted muscle contractions in most ranges of joint angle. However, responses to extensor muscle contractions are obtained when the tibia is held in full flexion due to specializations of the femoro-tibial joint. These responses could be of importance in signalling preparedness for a jump. Intracellular soma recordings of activity in individual receptors indicate that the organ contains two types of receptors: phasic units that respond to joint movement and tonic units that encode joint position and also show some response to movement. All units are directionally sensitive and respond only in limited ranges of joint angle. Some phasic units increase firing frequency with increasing rate of movement and thus encode joint velocity. Other phasic units fire only single action potentials and can encode only the occurrence and direction of joint movement. All tonic units increase activity in the extremes of joint position and show substantial hysteresis upon return to more median positions. Direct soma depolarization produces different responses in different types of units: phasic receptors show only transient discharges to current injection; tonic receptors exhibit sustained increases in activity that are followed by periods of inhibition of background firing upon cessation of current injection. Receptors of the chordotonal organ are separable into two major groups, based upon their response characteristics, soma location and dendritic orientation: a dorsal group of receptors contains tonic units that respond in ranges of joint flexion (joint angle 0–80°) and phasic units that respond to flexion movements; a ventral group of sensilla contains tonic units active in ranges of joint extension (joint angle 80–170°) and phasic receptors that respond to extension movements. The response properties of these receptors are discussed with reference to the potential functions of the chordotonal organ in the locust’s behavioural repertoire.
Energetic Efficiency of Vocalization by the Frog Physalaemus Pustulosus
Authors: Ryan Michael J. 
Published: April 2021

ABSTRACT
Male Physalaemus pustulosas consume, on average, 1.2µl of oxygen in the production of a single call, which is equivalent to an energy input per call of 0.024 J. The total power of complex calls, which can have a varying number of components, ranged from 0.36 to 0.46mW. The total acoustic energy contained in these complex calls ranged from 0.12 to 0.30mJ. The energetic efficiency of the vocalizations ranged from 0.5 to 1.2%, which is similar to the range estimated for some other animals. The low energetic efficiency of vocalization by these frogs is due, in part, to the fact that the wavelengths of the call are too long, relative to the size of the frog, to be radiated efficiently. Although shorter wavelengths (higher frequencies) are radiated by the frog at relatively greater intensities, longer wavelengths (lower frequencies) attenuate less rapidly in the environment. It is suggested that selection generated by the acoustics of the environment favours calls with lower frequencies, but the morphology of the animal sets a lower limit to which frequencies can evolve.
Analysis Of Respiratory Pattern During Panting In Fowl, Gallus Domesticus
Authors: Gleeson M. 
Published: April 2021

ABSTRACT
When exposed to hot environments, birds depend mostly on respiratory evaporative cooling in order to maintain body temperature since cutaneous evaporation is limited for most species because they lack sweat glands. As well as serving this thermoregulatory function the respiratory system must also accommodate the obligatory requirement of adequate gaseous exchange. The hyperthermic bird must increase ventilation rates over evaporative surfaces in the respiratory system and buccopharynx for cooling purposes and yet avoid a severe blood hypocapnia and alkalosis (Calder & Schmidt-Nielsen, 1968). Recently Bech, Johansen & Maloiy (1979) showed that flamingoes, Phoenicopterus ruber, avoid hypocapnia during panting by restricting hyperventilation to the respiratory dead-space. This is achieved by increasing respiratory frequency, f, but reducing tidal volume, VT, to a value which closely matches the tracheal dead-space volume, VD. AS a result of the diminished VT, carbon dioxide accumulated within the respiratory system and rapid, shallow panting was periodically interrupted by bursts of 1–3 deeper breaths which served to flush out the excess carbon dioxide. A similar pattern of breathing has been observed in domestic fowl by Gleeson & Brackenbury (1983). These authors showed that the carbon dioxide accumulated during rapid shallow breathing in the posterior (abdominal) air sacs as a result of the increase in the VD/VT ratio. Other authors have reported an increased f and reduced VT in the panting fowl (Kassim & Sykes, 1982; Arad & Marder, 1983) but the diphasic pattern of breathing during panting has not been adequately described or quantified although its presence is apparent from earlier records of breathing movements in the panting fowl (Romijn & Lokhorst, 1961). Some forms of diphasic panting also occur in other species of bird, although there is considerable variation in the frequency and regularity of the alternating patterns of breathing between species (for a review see Bech et al. 1979).
The Role of the Tympanal Membranes in the Tuning of Auditory Receptors in Tettigoniidae (Orthoptera: Ensifera)
Authors: Oldfield Brian Phillip 
Published: April 2021

ABSTRACT
One of the fundamental problems in auditory research is the origin of the frequency selectivity of auditory receptors. Horridge (1960) demonstrated that the auditory interneurones in locusts were tuned to different sound frequencies, thus suggesting that the auditory receptors were frequency selective. Michelsen (1968, 1971) established that the auditory organ of locusts contained four groups of receptors with different characteristic sound frequencies and proposed that the frequency selectivity of the individual groups was dependent on the resonant properties of the tympanum. Investigation using the more sensitive of the two auditory receptors in the moth Prodenia eridania extended this proposal by suggesting that the tuning of this receptor depended on both resonant properties of the auditory organ (scoloparium) and filtering properties of the acoustic system (Adams, 1972), the most important factor in the latter being the tympanal membranes. In crickets and bushcrickets, however, the tympanal membranes vibrate in a simple mode for a wide band of sound frequencies (Paton, Capranica, Dragsten & Webb, 1977; Michelsen & Larsen, 1978), thus making it unlikely that the motion of the tympanum is responsible for the frequency selectivity (Zhantiev & Korsunovskaya, 1978; Esch, Huber & Wohlers, 1980) of the individual auditory receptors. Similarly, Ball & Hill (1978) demonstrated that auditory intemeurones of larval instar crickets are tuned even though they have no tympanal membranes. A recent study of the tonotopic organization of the auditory organ in bushcrickets (Oldfield, 1982) revealed that the auditory receptors remained tuned after the removal of one tympanum. This result, like those obtained from crickets, suggests that the resonant properties of the tympanal membranes are not responsible for the tuning of the individual auditory receptors. Conclusive evidence on this proposal, however, requires the removal of both tympanal membranes, thus eliminating the possibility that the remaining tympanum in the study by Oldfield (1982) determined the tuning of the auditory receptors.
A Protective Effect of Adrenalin on the Acidotic Teleost Heart
Authors: Farrell A. P. 
Published: April 2021

ABSTRACT
In the teleost heart, catecholamines improve the tension development in isolated muscle strips and increase stroke volume (SVH) in perfused hearts working at sub-physiological levels (see Laurent, Holmgren & Nilsson, 1983 and Farrell, 1984 for recent reviews). Adrenalin (AD) can also restore or improve tension development during acidosis and anoxia (Gesser, Andresen, Brams & Sund-Laursen, 1982). However, physiological concentrations of AD do not increase SVH in any marked or consistent fashion in either intact fish or perfused hearts working at physiological levels (see Farrell, 1984), and only restore control levels of cardiac output in perfused hearts exposed to pH 7·4 at constant preload (Farrell, MacLeod, Driedzic & Wood, 1983). These observations pose the question: what is the role of catecholamine-mediated inotropic stimulation in fish?
Calcium Action Potentials in the Developing Oocytes of an Insect, Rhodnius Prolixus
Authors: O’Donnell M. J. 
Published: April 2021

ABSTRACT
Action potentials (APs) have been recorded for the first time from the oocytes of an arthropod, the haematophagous insect Rhodnius prolixus. In saline containing 2 mmol 1−1 calcium, APs could be evoked by depolarizing the oocyte membrane from its resting potential of –50 mV to a threshold between –35 and –40 mV. The mean duration and overshoot of the APs were 2·6 s and +16 mV, respectively. APs could not be evoked by depolarization of follicular epithelia that had been separated from the oocyte. It is concluded that the APs are generated at the oocyte cell membrane.. The overshoot of the APs was unaffected by the addition of tetrodotoxin (3 μmol 1−1) or the removal of Na+ (choline replacement) from the bathing saline. APs could be reversibly blocked by 1 mmol l− La or 10 mmol 1−1 Co2+. Verapamil at 50μmoll−1 and 100μmoll−1 reduced AP duration by 30% and 50%, respectively. The overshoot increased by 30 mV when bathing saline Ca2+ concentration was increased from 2 to 20 mmol 1−1. These results suggested the occurrence of a Ca2+ influx during the rising phase of the AP. Addition of Ba2+ increased the overshoot and duration of APs. In Ca2+-free saline, addition of 2 mmol 1−1 Ba2+ resulted in the spontaneous production of a series of action potentials. The duration of APs was as long as 120 s in 20 mmol 1−1 Ba2+ saline. It is suggested that Ba2+ may block a voltage-sensitive potassium conductance. Possible functions of action potentials during fertilization and early development are discussed.
The Maximum Shortening Velocity of Holothurian Muscle and Effects of Tonicity Change on It
Authors: Tsuchiya T. 
Published: April 2021

ABSTRACTThe maximum shortening velocity of the longitudinal retractor muscle of the holothurian, Isostichopus badionotus, was measured using a ‘slack test’ in solutions of normal, increased and reduced osmotic strength. At normal osmotic strength, the average maximum shortening velocity was 0·44 ± 0·04L0s−1(N = 14) which is fast compared to other smooth muscles. This is unexpected considering the slow locomotion of these animals. Raising the osmotic strength by 55% by addition of sucrose reduced the shortening velocity by more than 50%. Raising the osmotic strength by 52% with NaCl caused a 35% reduction in shortening velocity. Lowering the osmotic strength by 19% or 39%, by reducing NaCl concentration, did not significantly affect shortening velocity. The shortening velocity was found to be proportional to the volume of the muscle preparation.
Visual Position Information Controlling Smooth-Tracking in the Praying Mantis
Authors: Kirmse Wolfgang 
Published: April 2021

ABSTRACT
Smooth-tracking in the praying mantis was regarded by Rossel (1980, p. 325) as being driven by a velocity input signal in the same way that the optokinetic reaction is governed by the retinal image velocity of the surroundings. However, the following results indicate that the angular error between target position and midline of sight is also important in the control of smooth-tracking since there were increases in both saccadic and smooth torsion responses towards a stationary eccentric target in the open loop arrangement.
Mechanical Properties of the Myotomal Musculo-Skeletal System of Rainbow Trout, Salmo Gairdneri
Authors: Johnsrude C. L. , Webb P. W. 
Published: April 2021

ABSTRACT
Net forces and velocities resulting from in situ contractions of the myotomal musculature on one side of the body were measured at the hypural bones. Forces, velocities and power were determined with the body bent into a range of postures typical of those observed during fast-start swimming. For trout averaging 0·178 m in length and 0·0605 kg in body mass, the muscle system exerts a maximum normal force of 2·2 N at the base of the caudal fin. This force is equivalent to 11·8 kN m−2 based on the mean crosssectional area of the myotomal muscle. The maximum velocity was 1·11 ms−1, and the maximum mechanical power output, 0·64W, or 42·4 W kg−1 muscle.
Based on estimates of swimming resistance, these results would suggest acceleration rates of 7·5 to 16·5 ms−2, similar to averages observed during fast-starts. Maximum sprint speeds would range from 6·5 to 17·8 body lengths s−1, spanning the range of maximum speeds reported in the literature. It is suggested that maximum speed is limited by interactions between muscle contraction frequency and endurance.
Losses in the mechanical linkages between muscle fibres and propulsive surfaces were estimated at about 50% for power with possibly greater losses in force transmission.
Maximum force and power did not vary over the range of postures tested, supporting Alexander’s (1969) suggestions that white muscle should contract over a small portion of the resting length of the fibres.
Accessory Lymph Sacs and Body Fluid Partitioning in the Lizard, Sauromalus Hispidus
Authors: Smits Allan W. 
Published: April 2021

ABSTRACT
Chuckwalla lizards (genus Sauromalus) may accumulate substantial quantities of body fluid in extracoelomic, lateral abdominal spaces called accessory lymph sacs. The lymph sac fluid (LSF) of S. hispidus is similar to that of serum in Na+, K+ and Cl− concentrations, but the total protein content (3·58 ± 0·20 g dl−1) is only half that measured in serum (7·05 ± 0·26gdl−1). These analyses confirm that LSF is an extravascular form of extracellular fluid, similar in composition to true lymph. Measurements of body fluid partitioning by dilution analysis indicate that Sauromalus hispidus Stejnejer possesses a comparatively large (38·9% body mass) and labile extracellular fluid volume (ECFV), and that the volume of LSF is dependent on the ECFV. Expansion of the ECFV (and subsequent accumulation of LSF) is observed following large, intercompartmental fluid shifts from intracellular to extra cellular locations when lizards (1) are kept inactive in simulated hibernation, (2) are injected with KC1 in amounts similar to those found in their field diet, and (3) are hydrated with NaCl that is isotonic to their body fluids. These data collectively suggest that the lymph sacs of chuckwallas facilitate expansion of the ECFV, and may be adaptive not only as a means to store body water, but to accommodate transient shifts in body fluid from intracellular to extracellular locations.
Effect of Thermal Acclimation on Locomotor Energetics and Locomotor Performance in A Lungless Salamander, Desmognathus Ochrophaeus
Authors: Feder Martin E. 
Published: April 2021

ABSTRACT
To determine the effects of thermal acclimation upon locomotor performance and the rate of oxygen consumption during activity, small (&lt;3g), lungless salamanders, Desmognathus ochrophaeus Cope, were acclimated to three temperatures (5,13 and 21 °C) and exercised at various controlled speeds within an exercise wheel while their was measured. increased with speed at low speeds (&lt; 14 cm min−1). Although animals could sustain greater speeds, did not increase further. These small, exclusively skin-breathing salamanders could increase their 9–11 times during exercise and could sustain nearly half of the oxygen flux expected across a similar surface area of the mammalian lung. However, their maximum aerobic speed was remarkably slow (14cmmin−1) and their net cost of transport remarkably large (15–17 ml O2g−1km−1). Thermal acclimation affected during activity, the maximum sustainable speed and locomotor stamina in different ways. During exercise at 13°C, cold-acclimated animals had a significantly greater than warm-acclimated animals, but did not differ in stamina or the maximum sustainable speed. During exercise at 21 °C, cold acclimation did not affect the , significantly, but it decreased the stamina and increased the rate of lactate accumulation. Thus, these results suggest that thermal acclimation of the is not tightly coupled to thermal acclimation of locomotor performance in salamanders.
Respiratory Properties of Blood From Voluntarily and Forcibly Submerged Xenopus Laevis
Authors: Boutilier R. G. , Shelton G. 
Published: April 2021

ABSTRACT
The respiratory properties of blood from voluntarily diving Xenopus seem well matched to the animal’s habit of ventilating its lungs in an intermittent fashion. Compared with more terrestrial anurans, the high oxyhaemoglobin affinity (P50 = 29·6 Torr, pH 7·73, 25°C), Bohr effect (ΔlogP50/ΔpH = −0·37) and Haldane effect (0·37 mol CO2mol−1 O2) can be viewed collectively as adaptations towards effective blood gas storage during periods of apnoea and blood gas exchange during episodes of air breathing. It appears, therefore, that these biochemical adaptations are linked to the changes in respiratory blood flow that are made possible by the partially divided double circulation of Xenopus.
In comparison with blood from voluntarily diving Xenopus, that taken from animals at the end of a 30-min enforced dive was haemoconcentrated and contained 4 and 8 mmol l−1 higher concentrations of true plasma lactate and metabolic acid equivalents respectively. The pH-induced effects of the latter led to reductions in oxyhaemoglobin affinity and blood CO2 carriage, both of which persisted for up to 4h following emergence from an enforced dive. The associated haemoconcentration led to a secondary series of effects of which the most obvious were an elevated blood oxygen-carrying capacity and an increased non-bicarbonate buffer slope for true plasma. Marked changes, such as these, were never observed in blood samples taken at various stages of voluntary dives lasting upwards of 30 min.
The Regulation of Haemocyanin Oxygen Affinity During Emersion Of the Crayfish Austropotamobius Pallipes: II. An Investigation of In Vivo Changes in Oxygen Affinity
Authors: Morris S. , Tyler-Jones R. , Bridges C. R. , Taylor E. W. 
Published: April 2021

ABSTRACT
The oxygen-transporting properties of the haemolymph from the crayfish Austropotamobius pallipes were investigated. The haemolymph concentrations of K+, Mg2+ and Ca2+ ions, together with the concentration of L-lactate were measured in crayfish before, during and after 24 h emersion.
The concentrations of K+ and Mg2+ increased during aerial exposure and returned to pre-emersion levels during immersed recovery. Large increases in the level of circulating L-lactate and Ca2+ were correlated with short- and long-term aerial exposure respectively. Changes in the concentrations of these ions could also be correlated with changes in haemocyanin oxygen affinity. Reimmersion and recovery returned all parameters to near control values.
The effect, on haemocyanin oxygen affinity, of the Bohr shift alone was calculated and compared with the change in oxygen affinity (ΔP50) actually determined during aerial exposure. These data were also compared with predictions, calculated from in vitro data, for the potentiation of haemocyanin oxygen affinity by Ca2+ and L-lactate ions in aerially exposed crayfish. The physiological significance of the regulation of haemocyanin oxygen affinity by these ions is discussed.
Intercellular Communication in An Insect Endocrine Gland
Authors: Lococo D. J. , Thompson C. S. , Tobe S. S. 
Published: April 2021

ABSTRACT
The parenchymal cells of the corpora allata (CA) of the cockroach Diploptera punctata are coupled through low-resistance intercellular pathways. Extensive dye coupling of cells of CA from fourth instar and adult female cockroaches was revealed following iontophoretic injection of Lucifer Yellow. Freeze-etch electron microscopy revealed numerous gap-junction-like particles in CA cell plasma membranes. The spread of ionic current from cell to cell was demonstrated by injecting current pulses into one cell and recording electrotonic potentials from other cells. The amplitude of electrotonic potentials elicited by negative current injection varied inversely with the rate of juvenile hormone biosynthesis by the CA. The ‘length constant’ (distance at which an electrotonic potential in CA cells decays to 37% of its magnitude at the site of current injection) could not be measured accurately, but was found to be much greater than the length of the CA. Forskolin- and IBMX-induced elevation of intracellular cAMP increased the electrotonic potential but reduced juvenile hormone release of day 8 CA.
The Segmental Giant Neurone of the Signal Crayfish, Pacifastacus Leniusculus, and its Interactions With Abdominal Fast Flexor and Swimmeret Motor Neurones
Authors: Heitler W. J. , Darrig S. 
Published: April 2021

ABSTRACT
The anatomy and physiology of the segmental giant (SG) of the crayfish Pacifastacus leniusculus is described. The peripheral axon of the SG terminates in the 1st root near the base of the swimmeret, and has no direct target organ. There is a tuft of fine dendritic branches in the lateral neuropile where the SG axon has its smallest diameter. The central region of the SG has a conduction velocity of 1·3 ms−1, a length constant of 0·4–0·7 mm and an input resistance greater than 1·8MΩ. Dual microelectrode penetrations of pre- and postsynaptic neurones confirm that the SG receives input from the giant fibres through rectifying electrical synapses, and excites the fast flexor motor neurones of the abdomen, also through electrical synapses. The SG also excites a variety of swimmeret motor neurones, including power-and return-stroke classes. Attention is drawn to the similarity in anatomy between the SG and return-stroke swimmeret motor neurones, and a possible evolutionary explanation for the existence of the SG is proposed.