bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temperature and the Physiology of Intracellular and Extracellular Acid-Base Regulation in the Blue Crab Callinectes Sapid Us
Authors: Wood Chrism. , Cameron James N. 
Published: April 2021

ABSTRACT
The 14C-DMO/3H-inulin method for pHi was critically assessed in intact Callinectes and found to be reliable provided adequate equilibration time and significant radiolabel excretion were taken into account. An unusually high ‘mean whole body pHi’ (7·54 at 20°C compared with a pHa of 7·80) was due to a highly alkaline fluid compartment (pHi = 8·23) in the carapace. At 20°C the pHi of the heart was 7·35 and skeletal muscle pHi was 7·30, and there were small but consistent differences in the pHi of different muscle types. The change in pHa with temperature was −0·0151 u°C−1 between 10 and 30 °C, slightly less than the slope for the neutral pH of water (ΔpN/ΔT ≃ −0·0175 u °C−1). With data corrected to constant , this was associated with a change in [HCO3−]a between 10 and 20°C ( −0·13 mequiv l−1 °C−1, constant ) and a change in between 20 and 30 °C ( + 0-13 Torr °C−1, constant [HCO3−]a). The disturbing effect of relatively small changes on this pattern was demonstrated. ApHi/AT slopes for all tissues except carapace were not significantly different from pHa/AT but generally lower than ΔpN/ΔT. The slope for the. carapace was very flat and greatly influenced the ‘mean whole body pHi’ slope ( −0·0062u°C−1). In haemolymph in vitro at constant , ‘passive’ Δ [HCO3−]/ ΔT (−0·17mequivl −1°C−’ ) was comparable to that in vivo between 10 and 20 °C, independent of absolute , and directly related to total protein concentration. Haemolymph non-bicarbonate buffer value (μ) was similarly related to protein, but increased with temperature. Crabs subjected to an acute 20→10 °C shift showed initial overshoots of pHa and pHi associated with undershoot of , all of which were corrected over 24 h as [HCO3−]a rose. During this period there was a significant net uptake of acidic equivalents (base output) from the environment. The relevance of ‘passive’ Δ [HCO3−]/ ΔT in an open system to the observed in vivo effects is discussed.
Temperature Coupling and ‘Trade-Off’ Phenomena in the Acoustic Communication System of the Cricket, Gryllus Bimaculatus de Geer (GRYLLIDAE)
Authors: Doherty John A. 
Published: April 2021

ABSTRACT
The effects of ambient temperature on stridulation (calling song) in males, and phonotaxis in females, were studied in the chirping cricket, Gryllus bimaculatus. In the male, temperature had the greatest effect on the syllable and chirp repetition rates. Both increased linearly with increasing temperature between 15 and 24°C; there was no effect of temperature on these temporal properties at higher temperatures (24-33°C). Syllable duration, number of syllables per chirp and dominant frequency remained relatively unaffected by changes in temperature. Stridulation and phonotaxis were temperature coupled because the female at 15, 22 and 30°C responded best to synthetic songs with syllable and chirp repetition rates that matched these temporal properties of the male’s calling song at the same temperature. The phonotactic behaviour of the female indicates that certain combinations of temporal properties in the male’s calling Song improve the female’s response at different temperatures, suggesting the presence of ‘trade-off’ phenomena in phonotaxis and pattern recognition in G. bimaculatus.
Physiology of the Femoral Chordotonal Organ in the Stick Insect, Cuniculina Impigra
Authors: Hofmann T. , Koch U. T. , Bässler U. 
Published: April 2021

ABSTRACT
The femoral chordotonal organ of the stick insect Cuniculina impigra Redtenbacher (Phasmida) can be stimulated precisely by moving the receptor apodeme. Single sensory units in the sensory nerve are recorded using glass microelectrodes. The units are classified according to their sensitivity to (a) position, (b) position and velocity and (c) velocity. Nearly all transitional forms exist between the position and velocity receptors. Both elongation- and relaxation-sensitive receptors exist, and also units which are bi-directionally sensitive. Many position receptors have their maximum frequency at one of the extreme joint positions, but others have their maximum frequency near the middle position of the joint. Some velocity-sensitive units respond with equal sensitivity over the whole operating range of the joint, whereas other velocity receptors respond only in a part of the operating range, thus providing further evidence of range-fractionation.
Leg Thrust Important in Flight Take-Off in the Pigeon
Authors: Heppner Frank H. , Anderson John G. T. 
Published: April 2021

ABSTRACT
Measurements of the force generated by the legs of rock doves Columba livia during vertical and near-vertical take-off showed that the birds were able to develop an upward directed force of from 1·3 to 2·3 times their body weight. This force resulted in an instantaneous acceleration of 15·63 m s−2 at maximum thrust. Motion pictures taken during the take-off showed that as the birds’ feet left the experimental perch, their wings were in the overhead clap position. We suggest that the vertical take-off in birds is accomplished in three stages; leg thrust, clap-and-fling and steady-state flight.
The Effects Of Behaviourally Relevant Temperatures On Mechanosensory Neurones Of The Grasshopper, Schistocerca Americana
Authors: Miles Carol I. 
Published: April 2021

ABSTRACT
Grasshopper mechanosensory hair neurones respond to displacement of their associated hairs in a temperature sensitive manner: comparable increases in the number of spikes per stimulus result from increases in temperature with constant stimulus strengths and from increasing stimulus strengths at constant temperature. It is therefore not obvious that neurones in the CNS which receive inputs from mechanosensory hairs would be able to distinguish between these two parameters. The temperatures which populations of mechanosensory hairs on the thorax, head and tarsus experienced were measured in freely moving animals. Animals in thermally heterogeneous environments spent 90% of the accounted time in locations where thoracic temperatures of 32-44 °C were maintained (the behaviourally ‘preferred’ range). Head temperatures covered a wider range, and tarsal temperatures the widest. Different populations of mechanosensory hair neurones exhibited different sensitivities to temperature. Thoracic hair neurones were significantly more temperature sensitive than one of the two populations of head hairs studied, and tarsal hairs exhibited a pronounced temperature compensation in the behaviourally ‘preferred’ range. Wind sensitive head hairs, however, showed exceptionally high temperature sensitivities. There is a negative correlation between the temperature sensitivity of a population of mechanosensory hair neurones and the temperature variability to which those neurones are normally exposed. Implications of this correlation for the central interpretation of mechanosensory input are considered.
Spectral Sensitivity and Photo-Behaviour of the Water Mite Genus Unionicola
Authors: Dimock Ronald V. , Davids Cornelis 
Published: April 2021

ABSTRACT
Behavioural response spectra for phototaxis by four European species of water mites that are differently associated with freshwater mussels were determined. The wavelength for maximal stimulation of positive phototaxis and the corresponding energy threshold, were: 560nm and 3·6 × 10−7μW cm−2 for the free-living species Unionicola aculeata, 560 nm and 2·1 × 10−6μWcm−2 for the commensal U. bonzi, 600nm and 3·3 × 10−6μWcm−2 for the obligate symbiont U. ypsilophora, and 600 nm and 1·3 × 10−5μWcm−2 for the parasitic species U. intermedia. Sensitivity of these water mites to yellow-orange light is consistent with the spectral transmission of their native stream, the water of which readily absorbs wavelengths shorter than 500 nm.
U. intermedia exhibited wavelength-dependent phototaxis, with maximal positive phototaxis occurring in response to 600 nm light and negative phototaxis occurring at 440 nm. This differential photo-behaviour was not attributable to intensity effects. However, the positive phototaxis of this species to 600 nm light became negative when the mite was exposed to the chemical influence of its molluscan host. The spectral sensitivities of this acarine genus suggest the presence of at least two visual pigments within the taxon.
Short Communication Mechanoreceptors in the Fins of the Cuttlefish, Sepia Officinalis
Authors: Kier William M. , Messenger John B. , Miyan Jaleel A. 
Published: April 2021

ABSTRACT
Little is known about mechanoreceptors in cephalopods. The anatomical data are fragmentary; Graziadei (1964) described multipolar nerve cells in the arms of Octopus and the lips of Sepia and similar structures have been described in the mantle of Octopus (Sereni & Young, 1932) and Eledone (Alexandrowicz, 1960). While there is good physiological evidence for the existence of mechanoreceptors in the mantle of Octopus (Gray, 1960; Wilson, 1960; Boyle, 1976), mechanoreception in the mantle and fins of decapods has not been investigated. Here we present physiological evidence that there are receptors along the entire length of the cuttlefish fin that respond to mechanical stimuli. We also identify unusual structures in the fin whose distribution is consistent with their being these receptors.
Fields of View of the Eyes Of Primitive Jumping Spiders
Authors: Land M. F. 
Published: April 2021

ABSTRACT
Most spiders have eight simple eyes, of which one forward-pointing pair (the principal eyes) has a different structure from the other three pairs (the secondary eyes). The principal eyes are often movable, whereas the secondary eyes are fixed. In most jumping spiders (Salticidae) two of the secondary eyes, the postero-median pair, are so reduced that they seem to be vestigial, and their fields of view overlap those of the other secondary eyes (the antero-and postero-laterals) (Homann, 1928; Land, 1969a; Eakin & Brandenburger, 1971). However, in certain supposedly primitive Salticid sub-families the postero-median eyes are comparable in size with the other secondary eyes, and would appear to play a more equal part in the function of the secondary eye system, which is the detection of movement (Land, 1972). The origins of the Salticidae are something of a mystery, and it is therefore of considerable interest to see whether the fields of view of the eyes of these primitive sub-families give any clue that might indicate to which of the other spider families the Salticidae might be linked. The form of the fields of view appears to be a conservative feature in spider evolution (Land, 1985), just as does the layout of the eyes themselves. The anatomy and ultrastructure of these eyes have been described before (Blest, 1983, 1984, 1985; Blest & Sigmund, 1984) and the systematic position of the sub-family considered here, the Spartaeinae, is discussed by Wanless (1984).
Jamming Avoidance in the Electric Fish Eigenmannia: Harmonic Analysis of Sexually Dimorphic Waves
Authors: Kramer Bernd 
Published: April 2021

ABSTRACT
The present report shows an intraspecific, sexually dimorphic variation in harmonic content and waveform, as well as intensity, of the Electric Organ Discharges (EODs) in the green knife fish, Eigenmannia (Figs 2, 11). There is a close correlation between harmonic content of the EODs and waveform (as defined by the ratio of intervals between zero-crossings in the two half-waves of one EOD cycle; Fig. 3). The aim of the following experiments was to determine whether the fish are sensitive to differences in stimulus waveform or harmonic content. Stimulation with electric fields of various waveforms but equal peak-to-peak amplitudes at frequencies close to the fish’s frequency elicited the Jamming Avoidance Response (JAR) which is an EOD frequency change increasing the frequency difference (Watanabe & Takeda, 1963). The strength of JARs to distorted square wave and sawtooth stimuli was 25% smaller than that elicited by sine wave stimuli (Fig. 6). Undistorted square waves elicited stronger responses than sine waves, while undistorted sawtooth waves were the least effective (Table 1). The differences in response strength were proportional to differences in the intensity of the fundamental frequency or first harmonic, fi, of the stimulus waveforms. Subharmonic stimuli of nine artificial or synthesized natural waveforms at frequencies near one-half or one-third of the EOD resting frequency elicited responses only when a strong higher harmonic, or overtone, of the stimulus was close to the EOD fundamental frequency (Fig. 7). Stimuli of different waveforms, but identical spectral amplitudes, elicited similar responses not significantly different from each other, at stimulus frequencies near one-half (Table 3) and near the EOD resting frequency (Fig. 10). Eigenmannta’s JARs to synthesized male EODs at frequencies close to the fish’s frequency were weaker than those to female EODs of equal peak-to-peak amplitude. The weaker response was proportional to the weaker intensity of the first harmonic of the male EOD (Fig. 12). A stimulus frequency near one-half of the EOD baseline frequency evoked opposite results, as the second harmonic, f2, of the male EOD was relatively four times stronger than that of the female EOD (Table 4). Eigenmannia responded to jamming signals as if it performed a limited spectral amplitude (Fourier) analysis, determining the intensity of that stimulus harmonic (at least up to the third) enclosed within a narrow frequency band centred on its own EOD fundamental frequency. The assessment of that harmonic was independent of stimulus waveform, peak-to-peak amplitude, or power, demonstrating linear filtering of the stimulus wave. Because of Eigenmannia’s sensitivity to the harmonic content of the stimulus wave, as also demonstrated in subharmonic experiments, the natural variation of EODs in harmonic content may serve in species and mate recognition.
Locomotion of Hermit Crabs (Coenobita Compressus) on Beach and Treadmill
Authors: Herreid Clyde F. , Full Robert J. 
Published: April 2021

ABSTRACT
Coenobita compressus (H. Milne Edwards) walk forward on six legs using an alternating tripod gait similar to that of insects. The first walking leg provides the driving force for locomotion aided secondarily by the second walking leg, while the chelipeds act largely as supports. The left appendages are longer and heavier than the right, and they extend further laterally from the midline during their stride, thus compensating for the asymmetry of the crab which has a dextrally coiled shell and an abdomen displaced to the right. The abdomen is normally carried off the ground, but it is dragged when the shell is large.
Bilateral leg autotomy alters gait patterns; usually a diagonal quadrupedal gait was adopted. Walking was poor in crabs without chelae (L1 and R1) because of problems of balance. Crabs without their first walking legs (L2 and R2) were the most accomplished amputee walkers. Crabs lacking legs L3 and R3 showed the most gait diversity.
Velocity of travel is a function of crab size and the substrate walked upon. Large crabs travel faster than small ones on the beach by increasing their stride length rather than stepping frequency. Studies on a miniature treadmill showed individual crabs change velocity by changing both stepping frequency and stride length.
Snail shells of the genus Nerita are carried; they are the lightest shells on the beach. Shell mass for an individual may vary three-fold, but usually the masses of the shell and crab are similar. Crabs running with and without shells have the same step frequency and stride length.
Responsiveness of the Parotid Salivary Gland of Red Kangaroos (Macropus Rufus) to Mineralocorticoids
Authors: Beal A. M. 
Published: April 2021

ABSTRACT
During both acute and chronic mineralocorticoid administration, parotid saliva was obtained by acetylcholine stimulation at rates of 1·0–1·5 ml min−1 from anaesthetized red kangaroos. The Na/K ratio of saliva from chronically Na-replete kangaroos was virtually unaltered by ipsilateral intracarotid infusion of aldosterone at rates of 8, 40 or 80μgh−1 for 4h, the ratio falling from 20·1 ± 1·09 to 17·5 ± 0·53 (t6 = 2·07; NS) at 80μgh−1. Kangaroos given intramuscular injection of the mineralocorticoid, deoxycorticosterone (DOCA), at rates of 0· 25 or 0· 30mgkg−1 12h−1 showed a progressive fall in salivary Na/K ratio from 19· 1 ±0· 47 to 1· 76 ± 0· 41 (t5 = 27· 4; P&lt;0· 001) over the 21-day period of injection. The DOCA treatment caused hypertrophy of the ducts, particularly the intralobular ducts of the parotid gland. Aldosterone acetate given intramuscularly at 0· 03 mg kg−1 12h−1 for 10 days also reduced the Na/K ratio of the saliva. As soon as the salivary Na/K ratio had returned to replete values, some 3– 4 days after cessation of the DOCA injections, the kangaroos were given a 5-h infusion of aldosterone. Intracarotid infusion of aldosterone at 8 μgh−1 produced a near maximal fall in salivary Na/K ratio after 3 h of infusion, and increasing the infusion to 80μgh−1 had little additional effect. The minimum Na/K ratio obtained at this time was 5· 7 ± 1· 04 (t5 = 14· 21 ; P&lt; 0· 001), which was equivalent to the ratio obtained at 3– 6 days of DOCA injection. Significant regression of the intralobular ducts occurred during the 3 days following cessation of DOCA administration; 24 days after the end of DOCA treatment duct development was approaching that of Na-replete, untreated kangaroos.
The results demonstrate that the parotid glands of kangaroos from a sodium-rich environment are almost unable to respond to acute fluctuations in endogenous aldosterone levels; that chronically high levels of mineralocorticoids cause hypertrophy of the sodium-transporting ducts of the parotid gland, which results in an increasing ability to reduce the Na/K ratio of the saliva; and that responsiveness to mineralocorticoids declines rapidly in the absence of high mineralocorticoid levels due to regression of the ducts.
Respiration Beneath Desert Sand: Carbon Dioxide Diffusion and Respiratory Patterns in A Tenebrionid Beetle
Authors: Louw G. N. , Nicolson S. W. , Seely M. K. 
Published: April 2021

ABSTRACT
The massive dune sea of the southern Namib Desert is approximately 800 km in length and some 140 km wide. These dunes are among the highest in the world and, in spite of very sparse vegetation cover, they support a surprising variety of reptiles and arthropods (Koch, 1961 ; Louw & Seely, 1982). A feature of the arthropod fauna is the high species diversity of flightless tenebrionid beetles. These beetles do not construct burrows, but swim through the sand as if it were a fluid medium. For a description of the physical properties of dune sand see Lancaster (1981). Among the tenebrionids, Onymacris unguicularis is of special interest because it engages in fogbasking on the crests of the dunes when intermittent condensing fog occurs in the desert (Hamilton & Seely, 1976). This beetle occurs almost exclusively on the high slip-faces of the dunes, where it feeds on wind-blown plant detritus. To escape extremely high surface temperatures during midday and very low temperatures at night, O. unguicularis submerges beneath the sand to a depth of 5–10 cm for as much as 18 h per day (Seely, Mitchell & Louw, 1985). The present study assesses the respiratory consequences of such submergence by measuring the diffusion rate of carbon dioxide through a 5-crn layer of sand and the respiratory patterns, carbon dioxide production, and oxygen consumption of the beetles.
The Physiology of Wandering Behaviour in Manduca Sexta: III. Organization of Wandering Behaviour in the Larval Nervous System
Authors: Dominick Oliver S. , Truman James W. 
Published: April 2021

ABSTRACT
The locomotor patterns typical of wandering behaviour were studied electro-myographically in abdominal segments of freely moving larvae of Manduca sexta. Crawling locomotion consisted of stereotyped, anteriorly-directed, peristaltic waves of intersegmental muscle contraction. During burrowing the intersegmental muscles of all abdominal segments contracted simultaneously for several consecutive cycles and then performed a single bout of the crawling pattern. Sensory inputs determined which motor patterns were used and how they were modified. Local sensory inputs could modify patterns in the specific segments affected. The neural circuitry that was required to generate the peristaltic and bracing patterns was repeated among the thoracic and abdominal ganglia, and normally was activated by the suboesophageal ganglion (SEG) and brain. In the absence of connections with the SEG and brain the segmental motor pattern generators could be activated by strong sensory stimuli. When the thoracic and abdominal segments lacked connections with the SEG, spontaneous movements were infrequent prior to wandering, but increased markedly at wandering or following 20-hydroxyecdysone (20-HE) infusion. Prior to wandering the SEG drives spontaneous locomotion in debrained larvae, but this function disappears in wandering larvae, or following 20-HE infusion. Prior to wandering the brain exerted a net inhibitory influence on locomotion. Removal of the medial region of the brain abolished this inhibition, resulting in strong, continuous locomotion which was driven by the lateral region of the brain. This lateral excitatory function of the brain was not altered by 20-HE infusion prior to wandering, nor did it change with the appearance of wandering behaviour. We conclude that the locomotor patterns used during wandering are produced by pattern generators in the segmental ganglia and are modified by sensory information. The circuitry responsible for activating these motor pattern generators is associated with the SEG, and is under the control of the brain. The brain exerts a net inhibitory influence prior to wandering, which becomes excitatory during wandering. Ecdysteroids appear to alter locomotor function by acting at various levels including the segmental ganglia, the SEG and the brain. A model is advanced describing this effect.
Motion of Magnetotactic Microorganisms
Authors: S. Esquivel Darci Motta , De Barros Henrique G. P. Lins 
Published: April 2021

ABSTRACT
Magnetic moments for different magnetotactic microorganisms are obtained by electron microscopic analyses and studies of cell motion by optical microscopy. The results are analysed in terms of a model due to C. Bean. The considerations presented suggest that magnetotaxis is an efficient mechanism for orientation only if the time for reorientation is smaller than the mean time of environmental perturbations.
Function of the Epithelial Channel Cells of the Body Wall of A Terrestrial Slug, Ariolimax Columbianus
Authors: Martin A. W. , Deyrup-Olsen I. 
Published: April 2021

ABSTRACT
The body wall of the land slug Ariolimax columbianus Gould (Arionidae) secretes fluid in response to mechanical stimulation. This fluid is a product of specialized channel cells, with addition of mucus. Channel cell function can be explained in terms of ultrafiltration of blood components into the central channel, and modification of this ultrafiltrate, prior to extrusion from the body surface, by cellular transport of univalent ions but without change in osmotic pressure. Sodium and chloride ions are conserved, and potassium and bicarbonate ions are transferred out into the channel cell product. Agents known to affect epithelial transports and ion processing in a variety of animals - ouabain, amiloride, furosemide, SITS and acetazolamide - depress the function of the slug channel cells.