bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect of Temperature On the Waterproofing Mechanism of an INSECT
Authors: Beament J. W. L. 
Published: April 2021

ABSTRACT
Previous methods for determining the temperature characteristics of the permeability to water of insect cuticle are criticized on five fundamental points, and in particular it is shown that they do not measure the temperature of the cuticle which will be substantially different from that of the surrounding air. The physical principles for accurate measurement are outlined, involving the accurate control of air temperature and air circulation, the measurement of cuticle temperature and of water loss within a sealed enclosure, and the assessment of true saturation deficiency. Apparatus for meeting these requirements and making these measurements is described. Determinations have been made of the permeability of the cuticle of Periplaneta americana nymphs. When the permeability is plotted against cuticle temperature a sudden and substantial increase in permeability is seen to take place at around 30° C. The temperature at which this change occurs is higher the longer the time which has elapsed since the nymph previously moulted. A method of measuring the permeability of the cuticular grease, when spread as a layer over an isolated water droplet, is described. This layer, whose thickness is of molecular dimensions, has much greater absolute impermeability to water than the thick grease on the insect. It also exhibits a sudden increase in permeability at about 30° C., and the order of change is considerably greater than that found with intact cuticle. The findings are quantitatively compatible with the postulate that, at lower temperatures, the grease on the cockroach consists of an orientated ‘monolayer’ organized by the attraction of its polar groupings for the aqueous cuticle surface underlying it, together with a much greater thickness of unorganized grease above it. In absolute units, the grease is about five times as permeable to water as is the ‘monolayer’, but at the transition temperature the measurements agree with the supposition that the molecular organization of the ‘monolayer ‘breaks down into the disorganized state of the major part of the grease with a corresponding increase in permeability. The suggestion that films of grease on water, and the lowermost portion of the grease on the animal, have orientated molecular organization is supported by some observations on the effect of dust particles on the films and by information previously published.
The Induction and Termination of Facultative Diapause in the Chalcid Wasps Mormoniella Vitripennis (Walker) and Tritneptis Klugii (Ratzeburg)*
Authors: Schneiderman Howard A. , Horwitz Judith 
Published: April 2021

ABSTRACT
Many insects exhibit a facultative diapause which is under the control of specific environmental factors. When the insect enters diapause growth and development cease. The end of diapause is signalled by the resumption of development. In most instances the environmental agencies that cause diapause affect the generation that will enter diapause, but occasionally a stimulus applied to the maternal generation affects the post-embryonic stages of the progeny. Commonly in facultative diapause, normal growth proceeds for several moults after the application of the stimulus, and development ceases only at a later stage. Whatever the mechanism which finally prevents moulting and produces diapause, it does not interfere with intermediate moults. The present report defines the extrinsic factors that cause facultative diapause in the last larval instar of two parasitic wasps and analyses in detail the mechanism of diapause termination.
Measurement of Dissolved Oxygen in Swamp Waters. Further Modification of the Winkler Method
Authors: Beadle L. C. 
Published: April 2021

ABSTRACT
A modification of the iodine-difference Winkler method is described which involves a preliminary clarification of a single sample, from which two smaller samples are siphoned. This makes possible estimations on extremely muddy and polluted water and avoids an error in the standard iodine-difference method which is very large with highly polluted waters. The iodine is added with the clarifying reagents to the original sample, thus avoiding the necessity for quantitative addition of iodine to two separate samples, which is another potential source of error in the standard method. Estimations on swamp water saturated with air under standard conditions indicate that the method is accurate to within 0·2 mg. O2/l. With polluted water, having an oxidation-reduction potential (Eh) of less than + 100 mV.,’negative’ figures for oxygen content are obtained. The cause of this phenomenon could not be discovered but, since this potential indicates anaerobic conditions, the method is not thereby affected. An improved iodine-titration end-point is described involving the use of a magnetic stirrer. Direct spectrophotometric estimation of iodine is shown to be as accurate as, and very much more rapid than titration, and particularly suited to the iodinedifference method.
Studies On the Feeding and Nutrition of Tuberolachnus Salignus (Gmelin) (Homoptera, Aphididae)
Authors: Mittler T. E. 
Published: April 2021

ABSTRACT
Since Tóth (1940) questioned that the dietary nitrogen supply of aphids is adequate for their growth and reproduction, considerable controversy has existed regarding the necessity and ability of aphids to supplement their dietary nitrogen supply with atmospheric nitrogen through the agency of their symbiotic micro-organisms. Few data are available, however, on the amounts of nitrogen actually ingested, excreted, and assimilated by aphids. The aim of the present investigation was to determine these data for Tuberolachnus salignus (Gmelin), and to resolve the controversy for this species.
The Internal Rhythm of Reproduction in Xerophilous Birds Under Conditions of Illumination and Darkness
Authors: Marshall A. J. , Serventy D. L. 
Published: April 2021

ABSTRACT
A report that total darkness is more effective than illumination in the production of spermatogenesis in young of the xerophilous budgerygah is shown to be due to a misinterpretation of results. An internal rhythm of reproduction allows young male zebra finches (like young budgerygahs) to produce spermatozoa within 60 days in almost total darkness when provided with plenty of food and water at laboratory temperatures. Oocytes enlarge only slightly. Both sexes come into breeding dress in the dark. Various conditions of illumination (including decreasing photoperiods) cause in both sexes greater gametogenetic activity than occurs in darkness. Both budgerygah and zebra finch are xerophilous. They are opportunist breeders after rainfall, irrespective of season. Although they retain an ancestral capacity to respond to photostimulation, any such tendency under natural conditions could be over-ridden by external inhibitors. The rapid production of spermatozoa (within 60 days) is in both parrot and finch a physiological aspect of drought adaptation enabling very young birds to reproduce quickly whenever environmental conditions are propitious.
Comparison of Dehydration and Hydration of Two Genera of Frogs (Heleioporus and Neobatrachus) that Live in Areas of Varying Aridity
Authors: Bentley P. J. , Lee A. K. , Main A. R. 
Published: April 2021

ABSTRACT
Ability to take up water in response to dehydration and injection of posterior pituitary extract was measured in two genera of frogs, Heleioporus and Neobatrachus, that live in areas of varying aridity in south-west Australia. Species of Neobatrachus from dry areas took up water more rapidly than those from less dry ones. No such correlation could be seen in the species of Heleioporus. No differences could be seen in the ability of any of the animals to withstand desiccation. These findings are discussed in relation to the animals’ behaviour in its natural environment.
The Migration of Spermatozoa in the Female of Rhodnius Prolixus Stal
Authors: Davey K. G. 
Published: April 2021

ABSTRACT
Removal of the opaque accessory glands from a male Rhodnius prevents the normal migration of the spermatozoa in a female which is inseminated by it. The opaque accessory secretion induces rhythmic contractions in the oviducts, probably by acting through a peripheral nervous system. Paralysis of the muscles of the female without interfering with the motility of the spermatozoa prevents the ascent of the spermatozoa. Killing the spermatozoa in the bursa has no effect on their subsequent migration. The central nervous system is not essential for the migration. It is concluded that the migration of spermatozoa in the female of Rhodnius proxlixus is a result of rhythmic contractions set up in the oviduct by the opaque accessory secretion of the male acting through a peripheral nervous system. Evidence in the literature suggests that the mechanism may operate in a number of spermatophore-forming species.
Studies on the Myoneural Physiology of Echinodermata
Authors: Pople W. , Ewer D. W. 
Published: April 2021

ABSTRACT
Spontaneous activity is a well attested characteristic of holothurian muscle (Hill, 1926; du Buy, 1936a, Wells 1942). Some preparations show regular rhythmical contractions and have been used to test pharmacological reagents (Lutz, 1930; Wyman & Lutz, 1930; Iriye & Dille, 1941), while in other preparations the spontaneous activity is so variable that this is not considered possible (Riesser, 1933 ; Bacq, 1939; Ambache & Sawaya, 1953; Welsh, 1954). For certain preparations there has been no record of spontaneous activity (Morin, 1931 ; Fischer, 1938 ; Steinbach, 1940 ; Galambos, 1941 ; Prosser, Curtis & Travis, 1951 ; Prosser, 1954; van Weel, 1955). The variations between different preparations suggest that spontaneous activity is not an inevitable property of holothurian muscle, and in fact Tao (1927) and Buddington (1937) have shown that such activity depends, in part, on the presence of intact nervous tissue. Buddington (1937) studied the cloacal breathing of Thyone, and showed that the characteristic patterns of the spontaneous contractions of isolated muscles of the cloacal complex relate to the inherent functions of each muscle in the behaviour of the animal.
Flight Activity in the Blowfly, Calliphora Erythrocephala, In Relation to Wind Speed, with Special Reference to Adaptation
Authors: Digby Peter S. B. 
Published: April 2021

ABSTRACT
A study has been made of the effect of wind speed on the flight activity of a population of the blowfly Caltiphora erythrocephala in a small wind tunnel. Under the experimental conditions wind has an activating effect up to about 0’·7 m./sec., above which it inhibits flight. Below 0·5 m./sec., activity decreases rapidly with decrease of wind speed and then remains at or close to the lower value. The increase of activity arising from increase of wind speed is much slower, the state of low activity tending to persist. At speeds between 0·5 and 4·5 m./sec. the changes of activity in response to both increase and decrease of wind are very rapid and are followed by a considerable degree of adaptation in each case. Inhibition of activity by the change of wind speed from 0·5 to 4·5 m./sec. and to 8·0 m./sec. results from the movement of the third antennal joint relative to the head. When this antennal movement is prevented, the change to 4·5 m./sec. causes activation if the initial activity is low, and the change to 8·0 m./sec. causes an increase of walking activity although flight is decreased for mechanical reasons. Exposure to the higher speeds causes an additional depression of activity not dependent on movement of the third antennal joint.
The Effect of Temperature Changes on the Thyroid-Pituitary Relationship in Teleosts
Authors: Fortune P. Y. 
Published: April 2021

ABSTRACT
It is confirmed that TSH has a more marked effect on the teleost thyroid at high temperatures. The secretion of TSH is increased at high temperatures. The temperature to which the animal is subjected prior to the experiment has no long-term effect on thyroid activity. The thyroid-pituitary relationship is affected by temperature changes, and it is suggested that the TH : TSH ratio may be set at different levels by altering the environmental temperature.
The Electrical and Mechanical Responses of the Prothoracic Flexor Tibialis Muscle of the Stick Insect, Carausius Morosus Br
Authors: Wood D. W. 
Published: April 2021

ABSTRACT
The prothoracic flexor tibialis muscle of Carausius morosus consists of two lateral rows of pinnately arranged muscle units. Motor nerve endings of the ‘Doyére-cone’ type are distributed at intervals of approximately 60 p along each fibre. Each motor ending is probably innervated by two axons. Two types of responses have been found in the muscle fibres: (i) ‘fast’ electrical responses resembling the action potential of vertebrate muscles, associated with twitch-type contractions of the fibres; (ii) ‘slow’ readily facilitating responses resembling end-plate potentials, associated with slow, smooth contractions of the muscle, and with the maintenance of tonus. There is no evidence of peripheral motor inhibition. The muscle bathed in haemolymph is capable of developing a tetanus tension of 800 g./cm.2 cross-sectional area of individual muscle fibres. The tetanus : twitch ratio is over 25:1. Pharmacological substances which affect excitable tissues of other animals have no effect on the fast response. Progressively lowered temperatures lengthen the time course and reduce the amplitude of the fast response, but an active membrane response remains at 50 C. Refractoriness is evident near the peak of the fast response. The junctional potentials will summate if sufficiently close in time. It is suggested that the process underlying the fast response in Carausius is similar to that in the locust and in vertebrates ; but neuromuscular transmission does not appear to be cholinergic.
Excretion by the Malpighian Tubules of the Stick Insect, Dixippus Morosus (Orthoptera, Phasmidae): Amino Acids, Sugars and Urea
Authors: Ramsay J. A. 
Published: April 2021

ABSTRACT
Contrary to expectation, it is found that metabolically useful substances pass into the urine and are reabsorbed in the rectum. The kinetics of penetration have been investigated for six amino acids, three sugars and urea. The evidence indicates that these substances enter the urine by passive diffusion. The role of the Malpighian tubules in the insect’s excretory system is discussed in the light of these findings. It is suggested that the tubule is primarily a means whereby all soluble substances of low molecular weight are removed from the haemolymph and that in this respect it has analogies with the glomerulus as well as with the tubule of the vertebrate nephron.
Further Studies on Ionic Regulation in the Muscle Fibres of Carcinus Maenas
Authors: Shaw J. 
Published: April 2021

ABSTRACT
The muscle fibres of Carcinus maenas contain 91 mM./kg. fibre water of acid soluble phosphate compounds, of which arginine phosphate is the most abundant. These compounds behave passively under conditions of blood dilution and the phosphate radicals do not exchange freely with inorganic phosphate in the blood. Muscle potassium exchanges freely and completely with the blood potassium. The exchange constant is about 0·4 hr.−1. In the normal fibre potassium ions are approximately in equilibrium with those in the blood. Potassium is lost from the muscle when the blood potassium concentration is reduced, but both the muscle-to-blood potassium ratio and the membrane potential are increased. The behaviour of potassium appears to be largely passive but there may be some small active component in its retention. Muscle sodium exchanges very rapidly and completely with blood sodium. The exchange is complete in 10 min. Sodium is also lost rapidly from the muscle to Ringer solutions with a reduced sodium concentration. It is suggested that the bulk of the muscle sodium is situated in a region distinct from the true fibre interior and that sodium ions are rigidly excluded from the latter. These results are discussed in relation to the adaptation of the muscle fibre to reduced blood concentrations.
Unidirectional Movement Fibres from a Proprioceptive Organ of the Crab, Carcinus Maenas
Authors: Wiersma C. A. G. , Boettiger E. G. 
Published: April 2021

ABSTRACT
Proprioception in the legs of arthropods arises in receptor ceils more closely associated with structures of the joints than with muscles. Sensitive endings are located in special internally placed organs (Barth, 1934; Burke, 1954; Alexandrowicz & Whitear, 1957). Studies of the action potentials in the leg nerve during mechanical manipulation of the leg joints in Limulus (Pringle, 1956) and in certain arachnids (Pringle, 1955) have shown the presence of several types of proprioceptive endings. Slow-adapting tonic position fibres, some responding at the flexed and others at the extended positions, were shown to have their endings situated so as to react to strains in the cuticle. The rapidly adapting phasic fibres, however, originate in some internal structures, different fibres responding to the two directions of movement.
The Composition of the Blood of the Shore Crab, Carcinus Moenas Pennant, in Relation to Sex and Body Size
Authors: Gilbert A. B. 
Published: April 2021

ABSTRACT
The influence of body size and sex on the total osmotic pressure (O.P.) and blood conductivity of the shore crab was investigated. In both sexes the O.P. fell steadily as body weight increased. At any body weight the O.P. of the blood of male crabs was significantly higher that that of females. Blood conductivity increased in both sexes until a maximum was reached at a weight of about 35 g. Thereafter the conductivity fell as the weight increased. There was no significant difference in blood conductivity between male and female crabs below 35 g. body weight. Above 35 g. the conductivity of males was significantly higher than that of females.
A New Tonometric Method for the Determination of Dissolved Oxygen and Carbon Dioxide in Small Samples
Authors: Jones J. D. 
Published: April 2021

ABSTRACT
A microtonometric method is described whereby tensions of carbon dioxide, oxygen and nitrogen can be determined in fluid samples of 0·3 ml. volume or less, each determination taking 20·25 min. Replicate determinations of the tensions of carbon dioxide, oxygen and nitrogen give maximum coefficients of variability of 3·0, 2·2 and 1·2%, respectively. A comparison of the present method with a micro-Winkler method for the determination of dissolved oxygen shows a close agreement; the mean percentage difference being 3·0.
The Respiratory Centre in the Tench (Tinca Tinca L.)
Authors: Shelton G. 
Published: April 2021

ABSTRACT
The effects of brain transections on the breathing movements of the tench are described. The whole of the mid- and forebrain, and the cerebellum, can be removed without producing any change in the breathing movements. Normal movements continue after section of the IXth and Xth cranial nerves. Transections of the spinal cord and posterior medulla are without effect on the breathing rhythm until they reach a level just behind the facial lobe. The breakdown of respiration produced by transection at this level is interpreted as being due to removal of part of the respiratory centre. Rhythmically repeated movements in which the opercula abduct and the mouth closes are seen after transection in the posterior parts of the medulla. These movements are thought to be due to activity in neurones which are responsible for co-ordination of the coughs in the intact animal. These neurones are situated in the anterior part of the medulla, beneath the cerebellum.
Respiration Rates of Worker Honeybees of Different Ages and At Different Temperatures
Authors: Allen M. Delia 
Published: April 2021

ABSTRACT
The respiration rates of individual adult worker bees confined in small gauze cages were determined over a range of temperatures between 7 and 46°C. The respiration rates usually remained constant over a period of 1 hr., although at 7, 12° C., and possibly at 17° C. there were indications of a decrease with time, and at 42 and 46° C. indications of an increase with time. Fluctuations which would have reflected variable activity during any of the experiments were rare. At each temperature studied the respiration rates increased progressively from the youngest adults (newly emerged) to the oldest measured (24–33 days). The increase was particularly marked during the first few days of adult life. The respiration rates of newly emerged and 18 hr. old adults increased progressively between 7 and 46° C., but 4–33-day-old bees showed two peaks (at 17 and 46° C.) with a depression having a minimum value at 32° C. lying between. 2-day-old bees had similar peaks at 22 and 46° C. It is suggested that the first peak in the respiration rate of the older bees occurred at the lowest temperature at which free movements were possible, and that it indicated an increased body temperature maintained by the bees to combat the effects of the low environmental temperature. The lack of this first peak in the case of the youngest bees is thought to mean that they were unable to raise their temperature above that of the environment. The information obtainable from the literature supported these conclusions; their implications in relation to the regulation of temperature within the colony are discussed. Numerical values for the oxygen consumptions of adult bees are discussed in relation to those found by other workers.
Electroencephalographic Patterns of the Goldfish (Carassius Auratus L.)*
Authors: Schadé J. P. , Weiler Ivan Jeanne 
Published: April 2021

ABSTRACT
Bipolar surface electrodes were used to record electrical potentials from the brain of the goldfish, Carassius auratus L. Characteristic patterns of spontaneous electrical activity were described for telencephalon, mesencephalon, cerebellum and medulla oblongata. Changes in these patterns under deepening urethane narcosis were noted. Rapid repetitive flashing light caused a change in the normal pattern of the mesencephalon which resembled the mammalian arousal. High-frequency (18–24 cyc./sec.) low-amplitude activity replaced the characteristic low-frequency waves (7–14 cyc./sec.); the lower-frequency activity returned 1–5 min. after cessation of stimulation. Responses to single light flashes were described from the mesencephalon and cerebellum. An ‘A complex’ from the mesencephalon consisted of two to four rapid diphasic spikes, with a latency of 30–40 msec., duration of 40–50 msec., and amplitude of about 100 μ.V. A ‘B complex’ consisted of a large negative wave, duration 90–110 msec, and amplitude 100–200 μ,V., followed by a small positive deflexion, and a slow negative after-potential. The cerebellar response had a latency of 60–80 msec., duration of 100–120 msec., amplitude of 80–125 μV. The nature of these two components was discussed. Monocular blinding abolished the response to light in the contralateral half of the optic tectum and in the cerebellum. The amplitude of the low-frequency spontaneous activity characteristic of the mesencephalon was reduced in the contralateral tectum. Regional differences in the tectal response to single light flashes were described. Microelectrodes were used to record the photic response from deeper tectal layers. After destruction of parts of the retina by electrocautery, a disappearance of the A complex and 40–50% reduction of the B complex was observed in restricted tectal areas. The distribution of the areas of changed response was shown to correspond to a coarse overlapping projection of retinal quadrants of the fish eye on to the contralateral optic tectum. A possible basis for the localization of this projection, in agreement with anatomical and electrophysiological findings, was described.