bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Ontogeny of Aquatic Feeding Behavior in Salamandra Salamandra: Stereotypy and Isometry in Feeding Kinematics
Authors: Reilly Stephen M. 
Published: April 2021

ABSTRACT
To examine the extent to which aquatic prey-capture behavior in salamanders is stereotyped and how feeding kinematics scales with size, the ontogenetic variability of aquatic feeding behavior was examined in eight Salamandra salamandra. Feeding kinematics (seven duration and angular displacement variables), kinematic variance and capture performance were quantified and compared in the first several feedings after birth with a series of feedings 8 weeks later, just prior to metamorphosis. Analysis of variance revealed no statistically significant ontogenetic differences in the kinematic variables, and individual differences were found in only two variables (maximum gape angle and gape cycle time). A comparison of the relative kinematic variance within individuals revealed no significant differences in variance during ontogeny. In addition, capture success rate did not change. The strike is significantly faster than that of other salamanders. These results indicate that the initial prey-capture behavior remains unchanged throughout larval ontogeny. Thus, aquatic strike behavior in S. salamandra is developmentally fixed (innate) and does not appear to be influenced by learning or improvement in ‘skill’, supporting the hypothesis that aquatic salamander feeding is a highly stereotyped, unmodulated behavior. In addition, the lack of kinematic change through ontogeny indicates that feeding kinematics do not scale with body size, contrary to predictions that movements should be slower in larger animals.
Kinematics of Feeding in Bluegill Sunfish: is There a General Distinction Between Aquatic Capture and Transport Behaviors?
Authors: Gillis G. B. , Lauder G. V. 
Published: April 2021

ABSTRACT
Despite numerous studies of food transport in terrestrial vertebrates, little is known about this aspect of the feeding repertoire in aquatic vertebrates. Previous work had predicted that the kinematics of aquatic prey capture by suction feeding should be similar to those of prey transport. However, recent analyses of aquatic prey capture and transport in the tiger salamander Ambystoma tigrinum have contradicted this hypothesis, and document numerous differences between these two behaviors. In this study, using high-speed video and statistical analyses, we compare prey capture and transport kinematics in a ray-finned fish (Lepomis macrochirus, the bluegill sunfish) to examine the generality of differences between capture and transport behaviors in aquatic vertebrates. Compared with prey capture, prey transport is significantly more rapid and tends to have reduced lower jaw excursions, while having similar hyoid movements. A nested analysis of variance was used to analyze six variables common to both this analysis of Lepomis macrochirus and a previous study of Ambystoma tigrinum; none of these six variables showed significant variation between taxa. These results indicate that aquatic prey transport is kinematically distinct from capture behavior and that the distinctions between these two behaviors are remarkably consistent in two phylogenetically divergent lower vertebrate taxa. Such consistent kinematic differences have not been found in amniote taxa studied to date, but may constitute a plesiomorphic feature of vertebrate feeding systems.
Subcellular Localization and Biochemical Properties of the Enzymes of Carbamoyl Phosphate and Urea Synthesis in the Batrachoidid Fishes Opsanus Beta, Opsanus Tau and Porichthys Notatus
Authors: Anderson Paul M. , Walsh Patrick J. 
Published: April 2021

ABSTRACT
The subcellular localization and biochemical properties of the enzymes of carbamoyl phosphate and urea synthesis were examined in three representatives of fishes of the family Batrachoididae, the gulf toadfish (Opsanus beta), the oyster toadfish (Opsanus tau) and the plainfin midshipman (Porichthys notatus). The primary objective of the study was to compare the biochemical characteristics of these fishes, which represent a range between ammoniotelism and ureotelism (O. beta being facultatively ureotelic), with previous patterns observed for an ammoniotelic teleost (Micropterus salmoides, the largemouth bass) and an obligate ureogenic elasmobranch (Squalus acanthias, the dogfish shark). The present study documents the expression of mitochondrial carbamoyl phosphate synthetase (CPSase) III and cytosolic CPSase II (and its associated enzymes of pyrimidine synthesis, dihydro-orotase and aspartate carbamoyltransferase) in the livers of all three batrachoidid species. Both mitochondrial and cytosolic activities of arginase were present in the livers of all three species, as were cytosolic glutamine synthetase and argininosuccinate synthetase and lyase. However, O. beta also showed mitochondrial glutamine synthetase activity and higher total hepatic levels of glutamine synthetase than either O. tau or P. notatus. Taken together, these observations confirm that the arrangement of these enzymes in the batrachoidid fishes has greater similarity to that of M. salmoides than to that of S. acanthias. However, differences within the family appear to coincide with the different nitrogen excretion strategies. O. tau and P. notatus are primarily ammoniotelic and most closely resemble the ammoniotelic M. salmoides, whereas ureotelism in O. beta is correlated with the presence of a mitochondrial glutamine synthetase and the ability to induce higher total glutamine synthetase activities than O. tau or P. notatus. Additionally, isolated mitochondria from O. beta were able to generate citrulline from glutamine, whereas those from O. tau were not. Also in contrast to S. acanthias, glutamine synthetase activities in the mitochondria of O. beta are consistently lower than those of CPSase III. This and other kinetic observations lend support to the hypothesis that glutamine synthetase may be an important regulatory control point in determining rates of ureogenesis in O. beta.
Temperature And Myogenesis In Embryos Of The Atlantic Herring Clupea Harengus
Authors: Johnston Ian A. , Vieira Vera. L. A. , Abercromby Marguerite 
Published: April 2021

ABSTRACT
The development of axial muscles has been investigated in spring-spawning Atlantic herring (Clupea harengus L.) reared at 5, 8, 12 and 15 °C. In 1994, around 90 % of embryos hatched after 28 days at 5 °C, 16 days at 8 °C, 9 days at 12 °C and 8 days at 15 °C. The somites were formed from cells of the paraxial mesoderm in a rostral to caudal direction, starting at the neural plate stage. Somites were added at rates ranging from one every 3 h at 5 °C to one every 52 min at 15 °C. A small number of myoblasts, located adjacent and lateral to the notochord, elongated to span the somite to form mononuclear myotubes. The majority of muscle fibres were formed by the fusion of 2–5 myoblasts to produce multinucleated myotubes that subsequently differentiated into either superficial or inner fibre types. The timing of myogenesis with respect to somite stage and the initial appearance of the gut, pectoral fin buds and pronephric tubules was found to vary with development temperature. For rostral myotomes, the synthesis of contractile filaments and myofibril assembly were first observed at the 42-, 38-and 27-somite stages at 5, 8 and 12 °C, respectively. The differentiation of myotubes into morphologically recognisable muscle fibre types first occurred at the 62-somite stage at 5 °C, at the 48-somite stage at 8 °C and as early as the 40-somite stage at 12 °C. Cell proliferation experiments with 5-bromo-2′-deoxyuridine showed that another population of myoblasts was activated on the surface of muscle fibres just prior to hatching. Development temperature also affected muscle cellularity; there were 43 % more inner muscle fibres in the myotomes of 1-day-old larvae reared at 12 °C than at 5 °C (P&lt;0.02).
Energy Substrates for Flight in the Blister Beetle Decapotoma Lunata (Meloidae)
Authors: Auerswald Lutz , Gäde Gerd 
Published: April 2021

ABSTRACT
We investigated the substrates for flight in the blister beetle Decapotoma lunata by (a) establishing the patterns of maximum activities of enzymes of various metabolic pathways in the flight muscles, (b) measuring the respiratory rates of flight muscle mitochondria with various substrates and (c) determining metabolite concentrations in flight muscles and haemolymph during a flight period of up to 17 min and over a rest period of up to 2 h following 10 min of flight.
Activities of enzymes involved in proline metabolism (glutamate dehydrogenase, alanine aminotransferase, malic enzyme) were much higher in the blister beetle than in the migratory locust Locusta migratoria, whereas the activity of an enzyme responsible for fatty acid oxidation (-hydroxyacyl-CoA dehydrogenase) was much lower.
Mitochondria from flight muscles of D. lunata have a much higher capacity to oxidise proline than those from L. migratoria. The glycerophosphate shuttle, however, was equally active in both insects.
Whereas lipid levels in the haemolymph did not change significantly during flight, there was a continuous decrease in proline levels from 34.8 to 6.6 μmol ml-1 and a simultaneous increase in alanine concentration; carbohydrate levels dropped from 20.1 to 12.2 mg ml-1.
In the thorax (flight muscles), glycogen levels were diminished between 2 and 17 min of flight from 25.9 to 6.7 μmol glucose equivalents g-1 fresh mass. Proline concentration dropped continuously from an initial 49.5 to 10.1 μmol g-1 fresh mass, whereas alanine levels rose concomitantly from 2.9 to 17.3 μmol g-1 fresh mass.
After termination of a 10 min flight, pre-flight levels of proline in the haemolymph and flight muscles were only re-established after 2 h. In contrast, glycogen levels in the thorax were restored after 1 h.
Using the rates of utilisation of substrates during the first 10 min of flight to calculate rates of oxygen consumption during flight, it was shown that overall haemolymph substrates contribute 75 % and those of the flight muscles only 25 %. Although proline is an important substrate for flight in D. lunata, its role is secondary to that of carbohydrates. This type of substrate usage is different from that of the Colorado potato beetle Leptinotarsa decemlineata or the African fruit beetle Pachnoda sinuata, in which carbohydrates are of negligible or only slight importance, respectively.
Central Connections of Sensory Neurones From a Hair Plate Proprioceptor in the Thoraco-Coxal Joint of the Locust
Authors: Kuenzi F. , Burrows M. 
Published: April 2021

ABSTRACT
The hair plate proprioceptors at the thoraco-coxal joint of insect limbs provide information about the movements of the most basal joint of the legs. The ventral coxal hair plate of a middle leg consists of group of 10–15 long hairs (70 μm) and 20–30 short hairs (30 μm). The long hairs are deflected by the trochantin as the leg is swung forward during the swing phase of walking, and their sensory neurones respond phasically during an imposed deflection and tonically if the deflection is maintained. Selective stimulation of the long hairs elicits a resistance reflex that rotates the coxa posteriorly and is similar to that occurring at the transition from the swing to the stance phase of walking. The motor neurones innervating the posterior rotator and adductor coxae muscles are excited, and those to the antagonistic anterior rotator muscle are inhibited. By contrast, selective stimulation of the short hairs leads only to a weak inhibition of the anterior rotator. The excitatory effects of the long hairs are mediated, in part, by direct connections between their sensory neurones and particular motor neurones. A spike in a sensory neurone elicits a short-latency depolarising postsynaptic potential (PSP) in posterior rotator and adductor motor neurones whose amplitude is enhanced by hyperpolarising current injected into the motor neurone. When the calcium in the saline is replaced with magnesium, the amplitude of the PSP is reduced gradually, and not abruptly as would be expected if an interneurone were interposed in the pathway. Several sensory neurones from long hairs converge to excite an individual motor neurone, evoking spikes in some motor neurones. The projections of the sensory neurones overlap with some of the branches of the motor neurones in the lateral association centre of the neuropile. It is suggested that these pathways would limit the extent of the swing phase of walking and contribute to the switch to the stance phase in a negative feedback loop that relieves the excitation of the hairs by rotating the coxa backwards.
Tuning In To Fish Swimming Waves: Body Form, Swimming Mode And Muscle Function
Authors: Wardle C. S. , Videler J. J. , Altringham J. D. 
Published: April 2021

ABSTRACT
Most fish species swim with lateral body undulations running from head to tail. These waves run more slowly than the waves of muscle activation causing them, reflecting the effect of the interaction between the fish’s body and the reactive forces from the water. The coupling between both waves depends on the lateral body shape and on the mechanical properties of the tail. During steady swimming, the length of each myotomal muscle fibre varies cyclically. The phase relationship between the strain (muscle length change) cycle and the active period (when force is generated) determines the work output of the muscle. The muscle power is converted to thrust either directly by the bending body or almost exclusively by the tail, depending upon the body shape of the species and the swimming kinematics. We have compared the kinematics and muscle activity patterns from seven species of fish with different body forms and swimming modes and propose a model which yields a consistent pattern, with at least three extremes. Subtle tuning of the phase relationship between muscle strain and activation cycles can lead to major changes in the way muscles function in different swimming modes.
Optical Scaling in Conspecific Cataglyphis Ants
Authors: Zollikofer Christoph P. E. , Wehner Rüdiger , Fukushi Tsukasa 
Published: April 2021

ABSTRACT
This study examines the effects of body size variation on the optical properties of the compound eyes of visually guided desert ants belonging to the genus Cataglyphis. Although linear head size may vary by a factor of 2 within conspecific workers and most optical parameters change accordingly, the extent of the visual field remains constant. Comparative measurements carried out on workers of three species (C. albicans, C. bicolor and C. fortis) and on reproductive females and males of one species (C. bicolor) show that the form (size and shape) of the visual field is highly characteristic for each caste/species. A constant visual field is realised by reciprocal scaling rules for the number of ommatidia and the angular spacing of ommatidia. While larger ants have more ommatidia per compound eye, interommatidial angles are reduced accordingly, thus giving rise to a constant visual field. Among conspecific ant workers, the relationship between spatial visual acuity and eye size is similar to that found in interspecific comparisons and reflects optical constraints imposed on the design of the compound eye. Mapping of spatial visual directions onto the compound eye surface reveals a characteristic, inhomogeneous distribution of interommatidial spacing, particularly a foveal band with increased visual acuity in the vertical direction. This ‘visual stretch’ viewing the horizon is similar to that found in a variety of flying insects. Although, among conspecific workers, both the number of ommatidia and the interommatidial angles vary with varying head size, the overall pattern of interommatidial spacing is maintained so that corresponding positions on the compound eye of small and large individuals look in equivalent directions in space. These findings are in accordance with the observation that the shape of the compound eye surface, as expressed by the radius of curvature along cross sections, is similar in small and large ants.
Cage size and flight speed of the Tobacco Hawkmoth Manduca Sexta
Authors: Stevenson R. D. , Corbo Kathleen , Baca L. B. , Le Quang D. 
Published: April 2021

ABSTRACT
Flight speeds and behaviors of the sphinx moth Manduca sexta were recorded in chambers of four different sizes (0.57, 8.5, 44 and 447 m3). Mean horizontal speed increased linearly with the cube root of chamber volume from 0.57 m s−1 in the smallest chamber to 3.4 m s−1 in the largest. The maximum horizontal speed observed was 5.3 m s−1 in the largest chamber. Speeds decreased linearly with the logarithm of hawkmoth proximity to the wall. In a tunnel chamber (the third largest), moths often flew in a scalloped-shaped path. At the top of the scallop, they glided for 1–5 wing beats. In the largest chamber, moths could be recorded flying at angles other than horizontal (0°). At flight angles greater or less than 0 °, mean speed decreased linearly with angle until ±40 °. At greater angles, speeds remained between 1 and 2 m s−1. Moths also flew closer to the wall at flight angles deviating from the horizontal. An allometric analysis of the flight speeds of insects and birds suggests that M. sexta may be able to fly at 7–10 m s−1. We conclude that chamber size limits the flight speed and modifies the flight behavior of the tobacco hawkmoth.
Pulsatile Urea Excretion in the Ureagenic Toadfish Opsanus Beta: an Analysis of Rates and Routes
Authors: Wood Chris M. , Hopkins Todd E. , Hogstrand Christer , Walsh Patrick J. 
Published: April 2021

ABSTRACT
This study focused on the rates and routes of urea-N and ammonia-N excretion in the ureagenic toadfish and on the possibility that urea-N excretion occurs in pulses. Experimental approaches included the following: confinement in small individual containers with automated hourly sampling of water to follow temporal excretion patterns; divided chambers to separate excretion from the anterior and posterior parts of the fish; collection of urine and rectal fluid via chronic indwelling catheters; and gavage with [14C]-labelled polyethylene glycol 4000 to detect regurgitation of gastrointestinal fluids. When a standardized ‘crowding’ pre-treatment was employed to induce ureotelic behaviour, the fish exhibited significant elevations in the activity of glutamine synthetase in liver, kidney and gills, elevated plasma and bile urea-N levels, but unchanged ammonia-N and urea-N levels in most other body fluids. Unencumbered ureotelic fish confined in small containers excreted 82 % of their waste-N as urea-N and 18 % as ammonia-N; almost all (94 %) of this urea-N excretion occurred in a single pulse of less than 3 h duration about once every 24 h. This daily pulse did not occur by regurgitation of gut fluids, by excretion through prominent pores behind the pectoral fins or by discharge of rectal fluid or urine. Intestinal and urinary excretion accounted for less than 10 % of whole-body urea-N excretion and a negligible fraction of ammonia-N excretion. Pulsatile urea-N excretion occurred at the head end across the gills and/or body surface. Ammonia-N excretion, which was not pulsatile, also occurred largely through the head end. However, once the toadfish had been placed in divided chambers, urea-N excretion became continuous rather than pulsatile, and ammonia-N excretion increased greatly. A severe stress response was indicated by high levels of plasma cortisol, and the skin, which lacks scales, became a significant route of both ammonia-N and urea-N excretion. We speculate that the normal adaptive significance is that ureotelism facilitates cryptic behaviour, allowing the toadfish to virtually eliminate N-waste excretion during long periods while it remains sheltered in burrows. However, during severe stress, the effects of extremely high cortisol levels overwhelm the ammonia and urea retention mechanisms, and both substances leak across the general body surface.
Directional Sound Processing and Interaural Sound Transmission in a Small and a Large Grasshopper
Authors: Michelsen Axel , Rohrseitz Kristin 
Published: April 2021

ABSTRACT
Physical mechanisms involved in directional hearing are investigated in two species of short-horned grasshoppers that differ in body length by a factor of 3–4. The directional cues (the effects of the direction of sound incidence on the amplitude and phase angle of the sounds at the ears) are more pronounced in the larger animal, but the scaling is not simple.
At high frequencies (10–20 kHz), the sound pressures at the ears of the larger species (Schistocerca gregaria) differ sufficiently to provide a useful directionality. In contrast, at low frequencies (3–5 kHz), the ears must be acoustically coupled and work as pressure difference receivers. At 3–5 kHz, the interaural sound transmission is approximately 0.5 (that is, when a tympanum is driven by a sound pressure of unit amplitude at its outer surface, the tympanum of the opposite ear receives a sound pressure with an amplitude of 0.5 through the interaural pathway). The interaural transmission decreases with frequency, and above 10 kHz it is only 0.1–0.2. It still has a significant effect on the directionality, however, because the directional cues are large.
In the smaller species (Chorthippus biguttulus), the interaural sound transmission is also around 0.5 at 5 kHz, but the directionality is poor. The reason for this is not the modest directional cues, but rather the fact that the transmitted sound is not sufficiently delayed for the ear to exploit the directional cues. Above 7 kHz, the transmission increases to approximately 0.8 and the transmission delay increases; this allows the ear to become more directional, despite the still modest directional cues.
Functional Expression of a Cloned Drosophila Muscarinic Acetylcholine Receptor in a Stable Drosophila Cell Line
Authors: Millar Neil S. , Baylis Howard A. , Reaper Carolann , Bunting Richard , Mason William T. , Sattelle David B. 
Published: April 2021

ABSTRACT
A cloned Drosophila muscarinic acetylcholine receptor (mAChR) has been stably expressed in a Drosophila cell line (S2) under the control of an inducible Drosophila metallothionein promoter. A clonal cell line (S2–Dm1-1) has been isolated which, after induction of mAChR expression with CuSO4, exhibits high-affinity, saturable, specific binding of the muscarinic antagonist N-methyl scopolamine (NMS). The apparent molecular mass of the expressed protein, calculated by sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE), is in good agreement with the apparent molecular mass of mAChRs purified from Drosophila brain. Functional expression of the cloned mAChR in this stable cell line has been demonstrated by quantitative fluorescence ratio-imaging of Fura-2-loaded cells. We have observed transient, agonist-induced elevations in intracellular Ca2+ levels which can be completely blocked by atropine, whereas AFDX-116, a muscarinic antagonist which binds preferentially to the vertebrate mAChR M2 subtype, has little effect at 100 μmol l−1. The suitability of this stable Drosophila expression system for the characterization of neurotransmitter receptors is discussed.