bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wake Dynamics and Fluid Forces of Turning Maneuvers in Sunfish
Authors: Drucker Eliot G. , Lauder George V. 
Published: April 2021

ABSTRACT
While experimental analyses of steady rectilinear locomotion in fishes are common, unsteady movement involving time-dependent variation in heading, speed and acceleration probably accounts for the greatest portion of the locomotor time budget. Turning maneuvers, in particular, are key elements of the unsteady locomotor repertoire of fishes and, by many species, are accomplished by generating asymmetrical forces with the pectoral fins. The development of such left–right asymmetries in force production is a critical and as yet unstudied aspect of aquatic locomotor dynamics. In this paper, we measure the fluid forces exerted by the left and right pectoral fins of bluegill sunfish (Lepomis macrochirus) during turning using digital particle image velocimetry (DPIV). DPIV allowed quantification of water velocity fields, and hence momentum, in the wake of the pectoral fins as sunfish executed turns; forces exerted during turning were compared with those generated by the immediately preceding fin beats during steady swimming. Sunfish generate the forces required for turning by modulating two variables: wake momentum and pectoral fin stroke timing. Fins on opposite sides of the fish play functionally distinct roles during turning maneuvers. The fin nearer the stimulus inducing the turn (i.e. the strong side fin) generates a laterally oriented vortex ring with a strong central jet whose associated lateral force is four times greater than that produced during steady swimming. Little posterior (thrust) force is generated by the strong-side fin, and this fin therefore acts to rotate the body away from the source of the stimulus. The contralateral (weak-side) fin generates a posteriorly oriented vortex ring with a thrust force nine times that produced by the fin during steady swimming. Minimal lateral force is exerted by the weak-side fin, and this fin therefore acts primarily to translate the body linearly away from the stimulus. Turning with the paired fins is not simply steady swimming performed unilaterally. Instead, turning involves asymmetrical fin movements and fluid forces that are distinct in both direction and magnitude from those used to swim forward at constant speed. These data reflect the plasticity of the teleost pectoral fin in performing a wide range of steady and unsteady locomotor tasks.
Kinematics of Rotation in Place During Defense Turning in the Crayfish Procambarus Clarkii
Authors: Copp Newton H. , Jamon Marc 
Published: April 2021

ABSTRACT
The kinematic patterns of defense turning behavior in freely behaving specimens of the crayfish Procambarus clarkii were investigated with the aid of a video-analysis system. Movements of the body and all pereiopods, except the chelipeds, were analyzed. Because this behavior approximates to a rotation in place, this analysis extends previous studies on straight and curve walking in crustaceans.
Specimens of P. clarkii responded to a tactile stimulus on a walking leg by turning accurately to face the source of the stimulation. Angular velocity profiles of the movement of the animal’s carapace suggest that defense turn responses are executed in two phases: an initial stereotyped phase, in which the body twists on its legs and undergoes a rapid angular acceleration, followed by a more erratic phase of generally decreasing angular velocity that leads to the final orientation. Comparisons of contralateral members of each pair of legs reveal that defense turns are affected by changes in step geometry, rather than by changes in the timing parameters of leg motion, although inner legs 3 and 4 tend to take more steps than their outer counterparts during the course of a response. During the initial phase, outer legs 3 and 4 exhibit larger stance amplitudes than their inner partners, and all the outer legs produce larger stance amplitudes than their inner counterparts during the second stage of the response. Also, the net vectors of the initial stances, particularly, are angled with respect to the body, with the power strokes of the inner legs produced during promotion and those of the outer legs produced during remotion. Unlike straight and curve walking in the crayfish, there is no discernible pattern of contralateral leg coordination during defense turns. Similarities and differences between defense turns and curve walking are discussed. It is apparent that rotation in place, as in defense turns, is not a simple variation on straight or curve walking but a distinct locomotor pattern.
Pectoralis Muscle Performance During Ascending and Slow Level Flight in Mallards (Anas Platyrhynchos)
Authors: Williamson Michael R. , Dial Kenneth P. , Biewener Andrew A. 
Published: April 2021

ABSTRACT
In vivo measurements of pectoralis muscle length change and force production were obtained using sonomicrometry and delto-pectoral bone strain recordings during ascending and slow level flight in mallards (Anas platyrhynchos). These measurements provide a description of the force/ length properties of the pectoralis under dynamic conditions during two discrete flight behaviors and allow an examination of the effects of differences in body size and morphology on pectoralis performance by comparing the results with those of a recent similar study of slow level flight in pigeons (Columbia livia). In the present study, the mallard pectoralis showed a distinct pattern of active lengthening during the upstroke. This probably enhances the rate of force generation and the magnitude of the force generated and, thus, the amount of work and power produced during the downstroke. The power output of the pectoralis averaged 17.0 W kg−1 body mass (131 W kg−1muscle mass) during slow level flight (3 m s−1) and 23.3 W kg−1 body mass (174 W kg−1 muscle mass) during ascending flight. This increase in power was achieved principally via an increase in muscle strain (29 % versus 36 %), rather than an increase in peak force (107 N versus 113 N) or cycle frequency (8.4 Hz versus 8.9 Hz). Body-mass-specific power output of mallards during slow level flight (17.0 W kg−1), measured in terms of pectoralis mechanical power, was similar to that measured recently in pigeons (16.1 W kg−1). Mallards compensate for their greater body mass and proportionately smaller wing area and pectoralis muscle volume by operating with a high myofibrillar stress to elevate mechanical power output.
Prey-Capture Behavior in Gymnotid Electric Fish: Motion Analysis and Effects of water Conductivity
Authors: Maciver Malcolm A. , Sharabash Noura M. , Nelson Mark E. 
Published: April 2021

ABSTRACT
Animals can actively influence the content and quality of sensory information they acquire from the environment through the positioning of peripheral sensory surfaces. This study investigated receptor surface positioning during prey-capture behavior in weakly electric gymnotiform fish of the genus Apteronotus. Infrared video techniques and three-dimensional model-based tracking methods were used to provide quantitative information on body position and conformation as black ghost (A. albifrons) and brown ghost (A. leptorhynchus) knifefish hunted for prey (Daphnia magna) in the dark. We found that detection distance depends on the electrical conductivity of the surrounding water. Best performance was observed at low water conductivity (2.8 cm mean detection distance and 2 % miss rate at 35 μS cm−1, A. albifrons) and poorest performance at high conductivity (1.5 cm mean detection distance and 11 % miss rate at 600 μS cm−1, A. albifrons). The observed conductivity-dependence implies that nonvisual prey detection in Apteronotus is likely to be dominated by the electrosense over the range of water conductivities experienced by the animal in its natural environment. This result provides the first evidence for the involvement of electrosensory cues in the prey-capture behavior of gymnotids, but it leaves open the possibility that both the high-frequency (tuberous) and low-frequency (ampullary) electroreceptors may contribute. We describe an electrosensory orienting response to prey, whereby the fish rolls its body following detection to bring the prey above the dorsum. This orienting response and the spatial distribution of prey at the time of detection highlight the importance of the dorsal surface of the trunk for electrosensory signal acquisition. Finally, quantitative analysis of fish motion demonstrates that Apteronotus can adapt its trajectory to account for post-detection motion of the prey, suggesting that it uses a closed-loop adaptive tracking strategy, rather than an open-loop ballistic strike strategy, to intercept the prey.
Behavioural Assessment of Visual Acuity in Bumblebees (Bombus Impatiens)
Authors: Macuda Todd , Gegear Robert J. , Laverty Terence M. , Timney Brian 
Published: April 2021

ABSTRACT
The present study used previously developed techniques to measure resolution acuity in bumblebees (Bombus impatiens). Bees were required to discriminate between horizontal and vertical gratings in a Y-maze apparatus. The gratings had a mean luminance of 9 cd m−2 and a Michelson contrast of 84 %. For different bees, either the horizontal or vertical grating was rewarded. Rewarded gratings were associated with a sucrose and water solution (30 % sucrose by volume) and unrewarded gratings with plain water. Acuity estimates were established at several different viewing distances over several sessions using a method of constant stimuli. Visual acuity functions were generated from the performance data, and acuity thresholds were interpolated at a performance level of 65 % correct. When corrected for viewing distance, best angular acuity obtained for horizontal and vertical gratings was 0.35 and 0.36 cycles degree−1, respectively. These results are compared with those of the honeybee and discussed in the context of the bumblebee’s foraging behaviour.
Quantitative Tests of an Associative Theory of Risk-Sensitivity in Honeybees
Authors: Shapiro Martin S. , Couvillon P. A. , Bitterman M. E. 
Published: April 2021

ABSTRACT
Risk-sensitivity was studied in free-flying honeybees trained individually to choose between two scented targets (A and B) with varying amounts and concentrations of sucrose solution as reward. In the first phase of experiment 1, the animals showed ‘risk-aversion,’ preferring A, which provided 5 μl of a 40 % sucrose solution on every trial, to B, which provided 30 μl of the same solution once in every six trials (mean amount per trial 5 μl for each alternative). In the second phase, the preference reversed with reversal of the reward assignments. In experiment 2, the consistently rewarded A (5 μl of 40 % sucrose solution per trial) was again preferred, although the inconsistently rewarded B now provided twice the amount of sucrose solution on average (30 μl on two of every six trials, mean amount per trial 10 μl). In experiment 3, with A providing 10 μl of a 15 % sucrose solution on every trial and B providing 10 μl of a 60 % sucrose solution on two of every four trials (mean concentration per trial 30 %), the animals preferred B. In Experiment 4, patterned after experiment 1, similar results were obtained under more natural conditions in which the animals were no longer constrained (as they were in the first three experiments) to go equally often to each alternative. The results of all four experiments were predicted quantitatively and with considerable accuracy by a simple associative theory of discriminative learning in honeybees.
The Synchronisation of Signal Emission with Wingbeat During the Approach Phase in Soprano Pipistrelles (Pipistrellus Pygmaeus)
Authors: Wong Josephine G. , Waters Dean A. 
Published: April 2021

ABSTRACT
Previous studies have shown that, during search flight in bats, wingbeat, respiration and echolocation are synchronised in a 1:1 relationship. An efficiently integrated locomotor–respiratory system enables bats to produce intense echolocation signals at little or no cost above that required for flight. In this study, we investigated the coupling of wingbeat with echolocation in the laboratory during approach flight in soprano pipistrelles (Pipistrellus pygmaeus) using high-speed digital video at 250 and 500 frames s−1. We found that soprano pipistrelles most commonly produce single or double pulses per wingbeat. Single pulses per wingbeat occurred in two alternative positions: immediately before the end of the upstroke or after the start of the downstroke. Double pulses per wingbeat were emitted in the same wingbeat positions on the upstroke and the downstroke, as in single pulses per wingbeat. We suggest that, during approach flight, the coupling of more than one echolocation signal with a single wingbeat and expiratory cycle allows echolocation to remain energetically economic. When soprano pipistrelles approached a Perspex disc target, an increase in mean repetition rate was achieved by producing an extra pulse per wingbeat. Finally, we hypothesise that the bat’s approach to potentially interesting targets in the same horizontal plane as it’s flight path, i.e. during flapping flight, may be characterised by the production of double pulses per wingbeat, resulting in a unique pattern of echolocation pulse intervals.
Olfactory and Behavioural Responses of the Blood-Sucking bug Triatoma Infestans to Odours of Vertebrate Hosts
Authors: Guerenstein P. G. , Guerin P. M. 
Published: April 2021

ABSTRACT
Olfactory receptors in basiconic and grooved-peg sensilla on the antenna of fifth-instar Triatoma infestans nymphs respond to host odours. Gas chromatography analyses of host odour extracts coupled to electrophysiological recordings from basiconic sensillum receptors indicate that nonanal is a constituent of sheep wool and chicken feather odour that stimulates one of the receptors in this type of sensillum. Similar analyses revealed isobutyric acid in rabbit odour to be a chemostimulant for one of the receptors in grooved-peg sensilla. The response of the aldehyde receptor was higher to heptanal, octanal and nonanal than to other aliphatic aldehydes, and the response of the acid receptor was higher to isobutyric acid than to other short-chain branched and unbranched acids.
The behavioural responses of fifth-instar T. infestans nymphs to nonanal and isobutyric acid in an air-stream on a servosphere indicate that, whereas nonanal causes activation of the bugs, isobutyric acid induces an increase in upwind displacement, i.e. odour-conditioned anemotaxis. Binary mixtures of these compounds did not improve the attraction obtained with isobutyric acid alone. A comparison of the behavioural and electrophysiological responses of the bugs to different amounts of isobutyric acid in air suggests that attraction is obtained at concentrations that causes low-to-moderate increases in the firing rate of the acid-excited receptor in the grooved-peg sensilla, whereas at a dose that evokes relatively high firing rates (&gt;40 Hz) no attraction is obtained.
Coordinated Righting Behaviour in Locusts
Authors: Faisal A. A. , Matheson T. 
Published: April 2021

ABSTRACT
A locust placed upside down on a flat surface uses a predictable sequence of leg movements to right itself. To analyse this behaviour, we made use of a naturally occurring state of quiescence (thanatosis) to position locusts in a standardised upside-down position from which they spontaneously right themselves.
Locusts grasped around the pronotum enter a state of thanatosis during which the limbs can be manipulated into particular postures, where they remain, and the animal can be placed upside down on the ground. When released, thanatosis lasts 4–456 s (mean 73 s) before the animal suddenly becomes active again and rights itself within a further 600 ms. Thanatosis is characterised by very low levels of leg motor activity.
During righting, one hind leg provides most of the downward force against the ground that rolls the body around a longitudinal axis towards the other side. The driving force is produced by femoral levation (relative to the body) at the trochanter and by tibial extension. As the animal rolls over, the hind leg on the other side is also levated at the trochanter, so that it does not obstruct the movement. The forelegs and middle legs are not required for successful righting but they can help initially to tip the locust to one side, and at the end of the movement they help stop the roll as the animal turns upright. Individual locusts have a preferred righting direction but can, nevertheless, roll to either side.
Locusts falling upside down through the air use both passive and active mechanisms to right themselves before they land. Without active movements, falling locusts tend to rotate into an upright position, but most locusts extend their hind leg tibiae and/or spread their wings, which increases the success of mid-air righting from 28 to 49 % when falling from 30 cm.
The rapid and reliable righting behaviour of locusts reduces the time spent in a vulnerable upside-down position. Their narrow body geometry, large hind legs, which can generate substantial dorsally directed force, and the particular patterns of coordinated movements of the legs on both sides of the body are the key features that permit locusts to right themselves effectively. The reliability of autonomous multi-legged robots may be enhanced by incorporating these features into their design.
Heart Rate and Rate of Oxygen Consumption of Exercising Macaroni Penguins
Authors: Green J. A. , Butler P. J. , Woakes A. J. , Boyd I. L. , Holder R. L. 
Published: April 2021

ABSTRACT
Summary Twenty-four macaroni penguins (Eudyptes chrysolophus) from three groups, breeding males (N=9), breeding females (N=9) and moulting females (N=6), were exercised on a variable-speed treadmill. Heart rate (fH) and mass-specific rate of oxygen consumption were recorded from the animals, and both fH and were found to increase linearly with increasing treadmill speed. A linear regress.ion equation described the relationship between Fh and for each individual. There were no significant differences in these regressions between breeding and moulting females. There were significant differences in these relationships between all females and breeding males. fH and were recorded from five of these animals for a total of 24 h. When fH was used to predict for the 24 h period using the derived regressions, the estimate was not significantly different from the measured values, with .an average error of −2.1 %. When fH was used to predict for the 5 min intervals used for the calibration in all 24 birds, the estimate was not significantly different from the observed value. s, and the average error was only +0.47 %. Since the relationship was the same during periods of the annual cycle when the animals were inactive/fasting and active/foraging, it seems reasonable that, as long as sex differences are taken into account, fH can be used to predict the metabolic rates of free-ranging macaroni penguins all year round.
A New Technique for Monitoring the Behaviour of Free-Ranging Adélie Penguins
Authors: Yoda K. , Naito Y. , Sato K. , Takahashi A. , Nishikawa J. , Ropert-Coudert Y. , Kurita M. , Maho Y. Le 
Published: April 2021

ABSTRACT
Measurement of the time allocation of penguins at sea has been a major goal of researchers in recent years. Until now, however, no equipment has been available that would allow measurement of the aquatic and terrestrial behaviour of an Antarctic penguin while it is commuting between the colony and the foraging grounds. A new motion detector, based on the measurement of acceleration, has been used here in addition to current methods of inferring behaviour using data loggers that monitor depth and speed. We present data on the time allocation of Adélie penguins (Pygoscelis adeliae) according to the different types of behaviours they display during their foraging trips: walking, tobogganing, standing on land, lying on land, resting at the water surface, porpoising and diving. To illustrate the potential of this new technique, we compared the behaviour of Adélie penguins during the chick-rearing period in a fast sea-ice region and an ice-free region. The proportion of time spent standing, lying on land and walking during foraging trips was greater for penguins in the sea-ice region (37.6±13.3 % standing, 21.6±15.6 % lying and 5.9±6.3 % walking) than for those in the ice-free region (12.0±15.8 % standing, 0.38±0.60 % lying and 0 % walking), whereas the proportion of time spent resting at the water surface and porpoising was greater for birds in the ice-free region (38.1±6.4 % resting and 1.1±1.1 % porpoising) than for those in the sea-ice region (3.0±2.3 % resting and 0 % porpoising; means ± S.D., N=7 for the sea-ice region, N=4 for the ice-free region). Using this new approach, further studies combining the monitoring of marine resources in different Antarctic sites and the measurement of the energy expenditure of foraging penguins, e.g. using heart rates, will constitute a powerful tool for investigating the effects of environmental conditions on their foraging strategy. This technique will expand our ability to monitor many animals in the field.
Electrophysiological Analysis of the Neurotoxic Action of a Funnel-Web Spider Toxin, δ-Atracotoxin-HV1a, on Insect Voltage-Gated Na+ Channels
Authors: Grolleau Françoise , Stankiewicz Maria , Birinyi-Strachan Liesl , Wang Xiu-Hong , Nicholson Graham M. , Pelhate Marcel , Lapied Bruno 
Published: April 2021

ABSTRACT
The effects of δ-ACTX-Hv1a, purified from the venom of the funnel-web spider Hadronyche versuta, were studied on the isolated giant axon and dorsal unpaired median (DUM) neurones of the cockroach Periplaneta americana under current- and voltage-clamp conditions using the double oil-gap technique for single axons and the patch-clamp technique for neurones. In parallel, the effects of the toxin were investigated on the excitability of rat dorsal root ganglion (DRG) neurones. In both DRG and DUM neurones, δ-ACTX-Hv1a induced spontaneous repetitive firing accompanied by plateau potentials. However, in the case of DUM neurones, plateau action potentials were facilitated when the membrane was artificially hyperpolarized. In cockroach giant axons, δ-ACTX-Hv1a also produced plateau action potentials, but only when the membrane was pre-treated with 3-4 diaminopyridine. Under voltage-clamp conditions, δ-ACTX-Hv1a specifically affected voltage-gated Na+ channels in both axons and DUM neurones. Both the current/voltage and conductance/ voltage curves of the δ-ACTX-Hv1a-modified inward current were shifted 10 mV to the left of control curves. In the presence of δ-ACTX-Hv1a, steady-state Na+ channel inactivation became incomplete, causing the appearance of a non-inactivating component at potentials more positive than −40 mV. The amplitude of this non-inactivating component was dependent on the holding potential. From this study, it is concluded that, in insect neurones, δ-ACTX-Hv1a mainly affects Na+ channel inactivation by a mechanism that differs slightly from that of scorpion α-toxins.