bluuebunny/crossref_metadata_2025_split huggingface dataset:
Homing of Single Pigeons—Analysis of Tracks
Authors: Michener Martin C. , Walcott Charles 
Published: April 2021

ABSTRACT
Pigeons trained by releases along a constant compass line were repeatedly tracked to their lofts from the same training points 30-50 miles away. Their tracks differed from day to day by several miles, and the birds usually did not follow any obvious landmarks. The pigeons were released from new release points and on many of the tracks followed a definite sequence of orientation methods: the birds began flying in the same compass direction that had got them home from the training point, then they apparently switched to a rather accurate navigation method which got them to within 10 miles of the loft, where they seemed to pilot by a few familiar landmarks to the loft entrance. There is no evidence that most of the pigeons learned or could use landmarks extensively more than 10 miles from the loft, even over area which they crossed more than twenty times. The flight of pigeons from the training points and new release points at distances of 13 miles or more depended strictly on the visibility of the sun.
Spontaneously Induced Rhythm of Tidal Periodicity in Laboratory-Reared Carcinus
Authors: Williams Barbara G. , Naylor E. 
Published: April 2021

ABSTRACT
Laboratory-reared shore crabs show circadian rhythmicity which is transformed to approximate tidal rhythmicity after a period of chilling to 4° C. Periodogram analysis of the results characterizes the periodicity of the two types of rhythm, which suggest that the ability to show a rhythm of tidal periodicity is an inherited feature of shore-crab physiology.
Propulsion by Hispid Flagella
Authors: Holwill M. E. J. , Sleigh M. A. 
Published: April 2021

ABSTRACT
Equations are derived for the propulsive velocities and power dissipation of undulating hispid flagella. The observed rates of movement of water around the flagella of two chrysomonad flagellates and the translational speed of Ochromonas malhamensis agree closely with values calculated if it is assumed that the flagellar mastigonemes remain perpendicular to the flagellar surface and that these mastigonemes lie in two diametrically opposed rows situated in the plane of the flagellar wave.
Muscle Activity During Flight in Some large Lepidoptera
Authors: Kammer Ann E. 
Published: April 2021

ABSTRACT
The names and functions of the main mesothoracic flight muscles in Lepidoptera are reviewed. The wingbeat period in satumiid moths and monarch butterflies is long and variable. The three parameters, wingbeat period, burst length (number of times a motor unit is activated per wingstroke) and stroke amplitude are interdependent and positively correlated. Partial amputation of the wings in satumiids decreases wingbeat period. Cutting the sensory nerves from the wings increases the period. These results indicate that the influence of wing movement on wingbeat period is mediated by receptors near the base of the wing. The central nervous mechanisms which generate motor patterns during flight in Lepidoptera are discussed and compared with those in locusts. It is proposed that both mechanisms can be described by a single model, with minor differences in the mechanism of burst production.
The Relationship Between Blood Ions and Blood-Cell Density in Insects
Authors: Brady John 
Published: April 2021

ABSTRACT
Pairs of blood samples were taken from individual Periplaneta americana, the first sample being used for a live-blood haemocyte count and the second (collected 10 sec. later) for potassium and sodium determinations. Analysis of these matched data on cell count and whole-blood ion concentration reveals a positive correlation between the haemocyte density and the potassium concentration, the mean regression coefficient being +0·83 mM K+/1. of blood for 10,000 cells/μl. Similar analysis of the sodium data gives a negative correlation, with a mean regression coefficient of − 1·69 mM N+/1. for 10,000 cells/μl. Haematocrit estimations on heat-fixed blood, whose haemocyte density was simultaneously determined, indicate a mean haemocyte volume of 720 μ3. If the correlations relate entirely to the contents of the haemocytes, comparison with the haemocyte volume would indicate that the cell sap contains 115 mM/1. of potassium and probably less than about 60 mM/1. of sodium ; these levels are very similar to those reported for other tissues of the cockroach. Since cockroach blood contains relatively little potassium these figures suggest that a significant proportion of the whole-blood potassium may be contained within the haemocytes and so not be immediately available physiologically. Wounding is found to raise the haemocyte density by up to 4 times; at the same time the whole-blood potassium concentration rises and the sodium falls. A table is given comparing haemocyte counts and potassium levels in the blood of six closely studied insect species, the information having been compiled from different sources in the literature.
Current-Voltage Relations in the Isolated Giant Axon of the Cockroach Under Voltage-Clamp Conditions*
Authors: Pichon Y. , Boistel J. 
Published: April 2021

ABSTRACT
An experimental method of recording and controlling the membrane potential of a small area of the membrane of the cockroach giant axon is described. The recorded action potentials were essentially similar to those previously recorded by other methods. The membrane currents resemble those reported for the squid axon, the node of Ranvier in frog nerve and the lobster giant axon. Small cathodal polarizations gave only small outward currents; larger depolarizations (10–100 mV.) gave an initial inward current which changed into a delayed outward current. The initial inward current attained a maximum with depolarizing pulses of 40-50 mV. and showed a reversed, outward, flow of about 100 mV. Delayed outward currents increased continuously with increasing impulse voltage. The initial inward current was larger when the pulse was preceded by an hyperpolarizing prepulse. It is concluded that, although the early inward currents were in all probability related to Na+ ions and the delayed outward currents to K+ ions, the possible participation of Ca2+ and Cl− ions to the ionic currents cannot be excluded.
Short-Term Learning and Interocular Transfer in Detour Experiments with Octopuses
Authors: Wells M. J. 
Published: April 2021

ABSTRACT
Octopuses will make detours down a corridor with opaque walls and will make a correct left-right choice at the far end in order to attack a crab seen to one side of the passage through the transparent windows of a home compartment. In all, 1071 trials were carried out. In 883 of these a detour was completed, rightly or wrongly; in the remaining trials the octopuses failed to complete detours within 5 min. of the start of the trial. The percentage of errors rose with the time spent in the maze. Animals that completed their runs within 20 or 30 sec. of entering the corridor rarely made a mistake; animals that took 2 min. or more, whether due to imposed delays (animal shut in the corridor) or to slow exploration of the maze, made as many errors as correct responses. After removal of the vertical lobe from the brain the octopuses made more errors, particularly in the slower runs. There was also a higher proportion of trials at which they failed to complete a detour at all. These failures are not due to a failure of interocular transfer or to locomotor defects. The results are discussed in relation to the function of the vertical lobe, interocular transfer, the nature of representations of recent events within the optic lobes and the establishment of more permanent memory traces in discrimination experiments.
Integration of Visual Stimuli by the Crayfish Central Nervous System*
Authors: Wiersma C. A. G. , Yamaguchi T. 
Published: April 2021

ABSTRACT
For the crayfish, properties of visually reacting intemeurone types in the optic nerve are described on the basis of single-unit analysis. Sustaining fibres show : (a) ‘surround’ inhibition over the whole retina, including the excitatory field; (b) ‘on’ and ‘off’ effects at field boundaries; (c) a dark discharge in deteriorated preparations; (d) an increase in adapted firing rate and response to flashes in an ‘excited state’ of the preparation; (e) increased overall impulse frequency to fast-moving shadows at frequencies of 2–10/sec. which elicit short bursts. Dimming fibres, having mainly reversed properties, show: (a) bursts followed by adaptation to a lower ferquency level of spikes on light dimming; (b) total inhibition by illumination for times proportional to light intensity; (c) responsiveness to quickly moving shadows. ‘Jittery’ movement fibres lack directional sensitivity. Forthem: (a) total illumination and contrast have, within a wide range, no effect on discharges to moving targets; (b) large, dark cards moved at constant speed are seen only near their visual field boundary; (c) the less predictable the movement of a small dark object is, the longer its excitatory effect lasts; (d) responsiveness of field parts exposed is decreased for long durations; (e) no firing is caused by active or passive eye motions. Space-constant fibres show changed location and size of their excitatory fields with eye position. Their potential visual fields below the horizontal plane are un-responsive, due to inhibition caused mainly by statocyst input. Two eye muscle motor fibres, also under statocyst control, are influenced by fight on the limited sensory fields of two pairs of identifiable sustaining fibres. The two motor fibres, which innervate antagonistic muscles, are reversely excited and inhibited by these fields.
Temperature Acclimation of the Functional Parameters of the Giant Nerve Fibres in Lumbricus Terrestris L
Authors: Lagerspetz Kari Y. H. , Talo Antti 
Published: April 2021

ABSTRACT
Temperature acclimation in poikilotherms has been the subject of several recent reviews and symposia. Many of the acclimation phenomena occurring at the organismal or organ level have been shown to be accompanied by corresponding compensatory cellular changes. However, only in a few instances has thermal acclimation also been demonstrated to occur in isolated surviving tissues of animals (Precht & Christophersen, 1965; Lagerspetz & Dubitscher, 1966; Schlieper, 1966). In these cases of acclimation the mechanism of acclimation thus operates on the cellular or tissue level.
Temperature Acclimation of the Functional Parameters of the Giant Nerve Fibres in Lumbricus Terrestris L
Authors: Talo Antti , Lagerspetz Kari Y. H. 
Published: April 2021

ABSTRACT
The effect of temperature on the refractory period in nerve fibres is of the same magnitude as its effect on the duration of the action potential (Tasaki, 1949) or as the effect of temperature on the duration of the falling phase of the spike (Adrian, 1921). Temperature coefficients (Q10) as high as 4 have been calculated for the refractory period in single fibres of the frog by Schoepfle & Erlanger (1941). According to Tasaki (1949), the Q10 value of the absolute refractory period is about 3·5 for a single node in the myelinated fibres of the frog, when determined for the temperature interval 13·7-19° C.
The Circadian Flight Activity of the Mosquito, Anopheles Gambiae: Phase Setting by the Light Regime
Authors: Jones M. D. R. , Hill M. , Hope A. M. 
Published: April 2021

ABSTRACT
The circadian cycle of flight activity of individual, sugar-fed, Anopheles gambiae females has been studied, using the flight-sound as an indicator of activity. In an LD 12:12 régime (alternating 12 hr. light: 12 hr. dark), activity peaks follow both light-off and light-on. The mosquitoes are moderately active in the dark, but are inactive in the light after the first half-hour. If the light period is extended, the activity is delayed until light-off. Light appears to have an inhibitory effect, but the insects may show some activity towards the end of a 48 hr. light period. Cyclical activity continues in constant dark with a period of approximately 23 hr. A late light-off resets the cycle; an early light-off does not. When the LD 12:12 régime is advanced by 6 hr. the cycle is re-entrained within 2−3 days. Light in the second half of the subjective night appears to advance the cycle. It is suggested that the activity is controlled by an endogenous rhythm which possibly controls the release of an excitatory hormone. The effect of light may be mediated through an inhibitory hormone.
Sodium, Chloride and Water Balance of the Intertidal Teleost, Xiphister Atropurpureus
Authors: Evans David H. 
Published: April 2021

ABSTRACT
Studies were undertaken to determine the degree of regulation of sodium, chloride and water displayed by the intertidal teleost, Xiphister atropurpureus, over a range of salinities. The plasma concentrations of sodium and chloride declined by approximately 15 % in 10 % sea water (48 mM-Na/kg.) and the intracellular and extracellular spaces increased by approximately 6% in 10% sea water.
Sodium, Chloride and Water Balance of the Intertidal Teleost, Xiphister Atropurpureus
Authors: Evans David H. 
Published: April 2021

ABSTRACT
The rate of loss of sodium, chloride and water via the urine and the rate of intake of sodium, chloride and water by ingestion of the medium was determined for the euryhaline teleost, Xiphister atropurpureus. The urinary losses of sodium and chloride were approximately 0·5 mM/kg. fish/day in both 100% sea water (480 mM-Na/kg.) and 10% sea water. The ingestion of sodium and chloride by drinking the medium amounted to approximately 4 mM/kg. fish/day in 100% sea water and approximately o-i mM/kg. fish/day in 10% sea water. The low rate of urine flow in 10 % sea water and the low drinking rate in 100 % sea water indicate a relative impermeability to water in both salinities.
Respiration and Tracheal Ventilation in Locusts and other Flying Insects
Authors: Weis-Fogh Torkel 
Published: April 2021

ABSTRACT
In small insects there is no need for respiratory movements because the rate of diffusion of oxygen and carbon dioxide is adequate even during flight, but when the thorax is more than a few millimetres in diameter the primary tracheae or the air sacs which supply the wing muscles must be ventilated (Weis-Fogh, 1964b). Apart from various auxiliary mechanisms described by Miller (1960 a, 1964), the respiratory movements are of two different types: the well-known abdominal movements which result in abdominal pumping of air and haemolymph and the little-known movements of the thoracic walls which are caused by the wing movements themselves and which result in thoracic pumping at wingstroke frequency (Weis-Fogh, 1956a, 1964a). The existence of a thoracic mechanism has been suspected for a long time (du Buisson, 1924; Krogh, 1941; Krogh & Zeuthen, 1941) but was denied by Fraenkel (1932a) who investigated the abdominal respiratory movements and their control in a variety of large insects during tethered flight. Lack of suitable methods seems to have prevented further studies.
Active Transport by the Cecropia Midgut
Authors: Harvey W. R. , Haskell J. A. , Nedergaard S. 
Published: April 2021

ABSTRACT
From two lines of evidence, we conclude that the potassium transport gives rise directly to the midgut potential, i.e. that the active potassium transport mechanism is electrogenic. First, diffusion potentials of neither potassium, sodium, magnesium, calcium, nor chloride could give rise to the large midgut potential if values for tissue concentrations are accepted for their respective activities in the epithelium. Secondly, no externally added cation other than potassium is required to sustain either the potential or short circuit current, no specific anion is required, and no metabolic ion is known to be produced in sufficient amount to act as a counter ion for potassium in a non-electrogenic process. Changes in the concentration of potassium on the blood-side of the midgut always lead to changes in potential in the direction predicted by the Nernst equation. Moreover, a tenfold change in potassium concentration leads to the expected 59 mV. potential change provided that the prior midgut potential is at least 130 mV. This effect could be attributed either to the stimulation of an electrogenic potassium pump or to a potassium diffusion potential across the blood-side barrier.
Some Observations on the Role of the Body Wall of Acanthocephalus Ranae in Lipid Uptake
Authors: Hammond R. A. 
Published: April 2021

ABSTRACT
Acanthocephalus ranae has been found to take up glyceryl tri[oleate-9,10-3H] solely through the surface of the trunk. The proboscis and lemnisci play no part in the uptake of this material. The large amounts of lipid present in the latter organs may be evidence of their involvement in lipid excretion. Fat-soluble dyes are taken up by the animal and accumulate in lipid droplets in the lemnisci and proboscis wall. It is suggested that such dyes do not enter the animal through the surface of the proboscis, as has been suggested previously, but through the surface of the trunk. The structure of the acanthocephalan body wall is discussed in relation to the uptake of nutrients.
The Electrical Activity of the Radial Nerve in Diadema antillarum Philippi and Certain Other Echinoids
Authors: Millott N. , Okumura H. 
Published: April 2021

ABSTRACT
The propagated massed potentials which follow stimulation of the radial nerve in Arbacia, Diadema, Echinus and Paracentrotus are described. Approximate values for the averaged absolute and relative refractory periods and the conduction velocity were obtained. The response of Diadema has a double peak which is shown to represent responses of nerves differing in excitability and conduction velocity. The fast potential is concerned with spine movement. The slow potential is related to inhibition of spine movements excited photically.
The Location of Penetration Barriers in the Ganglia of the American Cockroach, Periplaneta americana (L.)
Authors: Eldefrawi M. E. , Toppozada A. , Salpeter M. M. , O’Brien R. D. 
Published: April 2021

ABSTRACT
The nature and location of the barrier system which partially protects the nervous system in insects has been investigated in the American cockroach by studying the fluxes of 14C-butanol, 14C-butyrate, 14C-butylamine and 3H-butyltrimethylammonium. Disruption of the sheath covering the ganglia has little effect on the influx of butanol and butyrate, but increased that of butylamine and butyltrimethylammonium. 2,4-Dinitrophenol slowed the influx of only those compounds whose metabolism it blocks. Effluxes show a fast and a slow component. Disruption of the sheath increases the amount but not the rate of the fast component; it raises the rate of the slow component for butanol, butyrate and butyltrimethylammonium, but not always. Nerve cords stained with methylene blue and freeze-sectioned show dye concentrated in the fat tissue surrounding the nerve cord, then in the neural lamella; a little penetrated the cell bodies of glia and neurones, but the neuropile was unstained. These findings suggest that the external sheath plays some part in restricting cation influx; apart from this the barrier system is a function of the whole ganglion, except that the neuropile may enjoy special protection.
Sodium Regulation in the Amphipod Gammarus duebeni Lilljeborg from Freshwater Localities in Ireland
Authors: Sutcliffe D. W. , Shaw J. 
Published: April 2021

ABSTRACT
A quantitative study of sodium influx and loss was made on populations of Gammarus duebeni obtained from four freshwater localities in Ireland. Characteristic features of sodium regulation in animals from the four localities were as follows, (a) The sodium influx increases gradually with increasing external sodium concentrations, but a maximum (saturation) level is abruptly reached at an external concentration of 1−2 mM/l. and the transporting system is half saturated at about 0·5 mM/l. sodium. (b) Over the range of sodium concentrations found in fresh waters a low rate of sodium uptake is sufficient to balance sodium losses at concentrations down to between 0·5 and 0·25 mM/l. At lower concentrations the influx is increased and the loss rate is reduced, (c) Calculations suggest that hypotonic urine containing approximately 40 mM/l. sodium is produced at external concentrations ranging from fresh water to 40 % sea water. At external concentrations below 0·25 mM/l. sodium the urine concentration is probably reduced to well below 40 mM/l. sodium. A detailed comparison is made of sodium regulation at external concentrations ranging between 0·07 and 1 mM/l. sodium in G. duebeni from fresh water in Ireland and from fresh water and brackish water in Britain. It is suggested that G. duebeni in Ireland constitutes a distinct physiological race adapted for living in fresh waters with relatively low sodium concentrations.
Motor Neurone Coupling in Locust Flight
Authors: Kendig Joan Johnston 
Published: April 2021

ABSTRACT
Techniques are described for recording in locust thoracic ganglia from single units identifiable as the motor neurones of specific flight muscles. There are at least two kinds of excitatory interactions among flight-muscle motor neurones. A spike in one motor neurone may be electrically transmitted to another with little delay but much attenuation. Stimulation of a group of motor neurones produces a second, probably chemically transmitted, potential with a latency of 5−6 msec. No short-term inhibitory interactions between motor neurones were observed. Activity in one motor unit of the flight system has long-term effects on the motor neurones of other units, excitatory in some cases and inhibitory in others. Single impulses in sensory neurones have little effect on motor neurones; sustained sensory input to a motor neurone produces a slow depolarization and increase in impulse frequency. Antidromic impulses in one group of motor neurones can entrain orthodromic impulses in another motor neurone. These data are discussed with reference to the hypothesis that the pattern of locust flight—rhythmic synchronous bursts of synergist activity, strict alternation between antagonists—can be produced by motor neurone interactions alone.
Influence of Temperature on the Transmembrane Potential of Ascaris Muscle Cells
Authors: DeBell Jean T. , Sanchez V. 
Published: April 2021

ABSTRACT
It has been shown that there is an almost linear inverse relationship between the transmembrane potential of the somatic muscle cells of Ascaris lumbricoides and the bath temperature between 38° and 20°C. It has also been shown that the spike frequency reflects these changes, decreasing at a rate of 0·6 impulse/sec./mV. D-Tubocurarine interferes with the response of these cells to thermal changes between 38° and 20° C. but it is ineffective below 20°C. It is proposed that the presynaptic nerve fibres are responsible for the thermal sensitivity of the muscle cells, since the amount of depolarizing neurohormone spontaneously released at the neuromuscular junctions would depend upon the temperature.