nils-herrmann/clean_scirepeval huggingface dataset:
Eye movements of vertebrates and their relation to eye form and function
Venue: Journal of Comparative Physiology A

The types of eye movements shown by all vertebrates originated in the earliest fishes. These consisted of compensatory movements, both vestibular and visual, to prevent image motion, and saccades to relocate gaze. All vertebrates fixate food items with their heads to enable ingestion, but from teleosts onwards some species also use eye movements to target particular objects, especially food. Eye movement use is related to the resolution distribution in the retina, with eyes that contain foveas, or areas of high ganglion cell density, being more likely to make targeting eye movements, not seen in animals with more uniform retinas. Birds, in particular, tend mainly to use head movements when shifting gaze. Many birds also make translatory head saccades (head bobbing) when walking. It is common for animals to use both eyes when locating food items ahead, but the use of binocular disparity for distance judgment is rare, and has only been demonstrated in toads, owls, cats and primates. Smooth tracking with eyes alone is probably confined to primates. The extent of synchrony and directional symmetry in the movements of the two eyes varies greatly, from complete independence in the sandlance and chameleon, to perfect coordination in primates.
Choosiness, a neglected aspect of preference functions: a review of methods, challenges and statistical approaches
Venue: Journal of Comparative Physiology A

Animals are faced with many choices and a very important one is the choice of a mating partner. Inter-individual differences in mating preferences have been studied for some time, but most studies focus on the location of the peak preference rather than on other aspects of preference functions. In this review, we discuss the role of variation in choosiness in inter-sexual selection. We define individual-level choosiness as the change in mating propensity in response to different stimulus signals. We illustrate general issues in estimating aspects of preference functions and discuss experimental setups for quantifying variation in choosiness with a focus on choices based on acoustic signals in insects. One important consideration is whether preferences are measured sequentially one stimulus at a time or in competitive multiple-choice setups; the suitability of these alternatives depends on the ecology of the study species. Furthermore, we discuss the usefulness of behavioural proxies for determining preference functions, which can be misleading if the proxies are not linearly related to mating propensity. Finally, we address statistical approaches, including the use of function-valued trait analysis, for studying choosiness. Most of the conclusions can be generalized beyond acoustic signals in insects and to choices in non-sexual contexts.
The nervous and the immune systems: conspicuous physiological analogies
Venue: Journal of Comparative Physiology A

From all biological constituents of complex organisms, two are highly sophisticated: the nervous and the immune systems. Interestingly, their goals and processes appear to be distant from each other; however, their physiological mechanisms keep notorious similarities. Both construct intelligence, learn from experience, and keep memory. Their precise responses to innumerable stimuli are delicately modulated, and the exposure of the individual to thousands of potential challenges integrates their functionality; they use a large part of their constituents not in excitatory activities but in the maintenance of inhibitory mechanisms to keep silent vast intrinsic potentialities. The nervous and immune systems are integrated by a basic cell lineage (neurons and lymphocytes, respectively) but each embodies countless cell subgroups with different and specialized deeds which, in contrast with cells from other organs, labyrinthine molecular arrangements conduct to “one cell, one function”. Also, nervous and immune actions confer identity that differentiates every individual from countless others in the same species. Both systems regulate and potentiate their responses aided by countless biological resources of variable intensity: hormones, peptides, cytokines, pro-inflammatory molecules, etc. How the immune and the nervous systems buildup memory, learning capability, and exquisite control of excitatory/inhibitory mechanisms constitute major intellectual challenges for contemporary research.
Synergistic effects of acute warming and low pH on cellular stress responses of the gilthead seabream Sparus aurata
Venue: Journal of Comparative Physiology B

The present study assesses the resilience of the Mediterranean gilthead seabream (Sparus aurata) to acute warming and water acidification, using cellular indicators of systemic to molecular responses to various temperatures and CO2 concentrations. Tissue metabolic capacity derived from enzyme measurements, citrate synthase, 3-hydroxyacyl CoA dehydrogenase (HOAD), as well as lactate dehydrogenase. Cellular stress and signaling responses were identified from expression patterns of Hsp70 and Hsp90, the phosphorylation of p38 MAPK, JNKs and ERKs, from protein ubiquitylation and finally from the levels of transcription factor Hif-1α as an indicator of systemic hypoxemia. Exposure to elevated CO2 levels at temperatures higher than 24 °C generally caused an increase in fish mortality above the rate caused by warming alone, indicating effects of the two factors and a failure of acclimation and thus the limits of phenotypic plasticity to be reached. As a potential reason, tissue-dependent induction and stabilization of Hif-1α indicate hypoxemic conditions. Their exacerbation by enhanced CO2 levels is linked to the persistent expression of Hsp70 and Hsp90, oxidative stress and activation of MAPK and ubiquitin pathways. Antioxidant defence is enhanced by expression of catalase and glutathione reductase, however, leaving superoxide dismutase suppressed by elevated CO2 levels. On longer timescales in specimens surviving warming and CO2 exposures, various metabolic adjustments initiate a preference to oxidize lipid via HOAD for energy supply. These processes indicate significant acclimation up to a limit and a time-limited capacity to survive extreme conditions passively by exploiting mechanisms of cellular resilience.
Electrocardiogram, heart movement and heart rate in the awake gecko (Hemidactylus mabouia)
Venue: Journal of Comparative Physiology B

The electrocardiogram (ECG) is the simplest and most effective non-invasive method to assess the electrical activity of the heart and to obtain information on the heart rate (HR) and rhythm. Because information on the HR of very small reptiles (body mass <10 g) is still scarce in the literature, in the present work we describe a procedure for recording the ECG in non-anesthetized geckos (Hemidactylus mabouia, Moreau de Jonnès, 1818) under different conditions, namely manual restraint (MR), spontaneous tonic immobility (TI), and in the non-restrained condition (NR). In the gecko ECG, the P, QRS and T waves were clearly distinguishable. The HR was 2.83 ± 0.02 Hz under MR, which was significantly greater (p < 0.001) than the HR under the TI (1.65 ± 0.09 Hz) and NR (1.60 ± 0.10 Hz) conditions. Spontaneously beating isolated gecko hearts contracted at 0.84 ± 0.03 Hz. The in vitro beating rate was affected in a concentration-dependent fashion by adrenoceptor stimulation with noradrenaline, as well as by the muscarinic cholinergic agonist carbachol, which produced significant positive and negative chronotropic effects, respectively (p < 0.001). To our knowledge, this is the first report on the ECG morphology and HR values in geckos, particularly under TI. The methodology and instrumentation developed here are useful for non-invasive in vivo physiological and pharmacological studies in small reptiles without the need of physical restraint or anesthesia.
Acclimation to different environmental salinities induces molecular endocrine changes in the GH/IGF-I axis of juvenile gilthead sea bream (Sparus aurata L.)
Venue: Journal of Comparative Physiology B

AbstractTo assess the role of 
the GH/IGF-I axis in osmotic acclimation of the gilthead seabream Sparus aurata, juvenile specimens were acclimated to four environmental salinities: hyposmotic (5 ‰), isosmotic (12 ‰) and hyperosmotic (40 and 55 ‰). The full-length cDNAs for both pituitary adenylate cyclase-activating peptide (PACAP) and prepro-somatostatin-I (PSS-I), the precursor for mature somatostatin-I (SS-I), were cloned. Hypothalamic PACAP and PSS-I, hypophyseal growth hormone (GH) and prolactin (PRL), and hepatic insulin-like growth factor-I (IGF-I) mRNA expression levels were analyzed in the four rearing salinities tested. PACAP and IGF-I mRNA values increased significantly in response to both 5 and 55 ‰ salinities, showing a U-shaped curve relationship with the basal level in the 40 ‰ group. Hypothalamic PSS-I expression increased strongly in the 55 ‰ environment. GH mRNA levels did not change in any of the tested environmental salinities. PRL mRNA maximum levels were encountered in the 5 and 12 ‰ environments, but significantly down-regulated in the 40 ‰. Plasma cortisol levels significantly increased in the 40 ‰ environment. These results are discussed in relation to the well-known high adaptability of Sparus aurata to different environmental salinities and the role of the GH/IGF-I axis in this process.
The thermal plasticity of locomotor performance has diverged between northern and southern populations of the eastern newt (Notophthalmus viridescens)
Venue: Journal of Comparative Physiology B

Many temperate ectotherms undergo thermal acclimation to remain functional over a wide range of body temperatures, but few studies have investigated whether populations of a single species have evolved differences in the thermal plasticity of locomotor performance. Therefore, we asked whether the thermal plasticity of locomotor performance has diverged between northern and southern populations of eastern newts (Notophthalmus viridescens). We acclimated eastern newts from Florida and Maine to cold (6 °C) or warm (28 °C) conditions for 12 weeks. Following acclimation, we measured the burst speed of newts at 6, 11.5, 17, 22.5, 28, and 33.5 °C. We also measured the activities of creatine kinase (CK) and lactate dehydrogenase (LDH) in skeletal muscle of newts. The newts from Maine were better able to acclimate to low temperature compared to newts from Florida. Regardless of acclimation, the thermal sensitivity of burst speed was higher in the Florida compared to the Maine population. In general, newts from Maine performed better at low temperatures, whereas newts from Florida performed better at high temperatures. The activities of CK and LDH were lower in cold compared to warm-acclimated newts in the Florida population, but acclimation did not affect the activities of these enzymes in the Maine population. The activities of CK and LDH do not explain differences in the thermal plasticity of locomotor performance between populations. Our results demonstrate that the thermal sensitivity and plasticity of locomotor performance differ between northern and southern populations of eastern newts, suggesting that these traits readily adapt to the thermal environment.
Selective forces on origin, adaptation and reduction of tympanal ears in insects
Venue: Journal of Comparative Physiology A

Insect ears evolved many times independently. As a consequence, a striking diversity exists in the location, construction and behavioural implementation of ears. In this review, we first summarise what is known about the evolutionary origin of ears and the presumed precursor organs in the various insect groups. Thereafter, we focus on selective forces for making and keeping an ear: we discuss detecting and localising predators and conspecifics, including establishing new “private” channels for intraspecific communication. More advanced aspects involve judging the distance of conspecifics, or assessing individual quality from songs which makes auditory processing a means for exerting sexual selection on mating partners. We try to identify negative selective forces, mainly in the context of energy expenditure for developing and keeping an ear, but also in conjunction with acoustic communication, which incorporates risks like eavesdropping by predators and parasitoids. We then discuss balancing pressures, which might oppose optimising an ear for a specific task (when it serves different functions, for example). Subsequently, we describe various scenarios that might have led to a reduction or complete loss of ears in evolution. Finally, we describe cases of sex differences in ears and potential reasons for their appearance.
Flow sensing in developing Xenopus laevis is disrupted by visual cues and ototoxin exposure
Venue: Journal of Comparative Physiology A

We explored how lateral line cues interact with visual cues to mediate flow sensing behaviors in the nocturnal developing frog, Xenopus laevis, by exposing animals to current flows under different lighting conditions and after exposure to the ototoxin gentamicin. Under dark conditions, Xenopus tadpoles move downstream at the onset of current flow, then turn, and orient toward the direction of the flow with high accuracy. Postmetamorphic froglets also exhibit positive rheotaxis but with less accuracy and longer latency. The addition of discrete light cues to an otherwise dark environment disrupts rheotaxis and positioning. Orientation is less accurate, latency to orient is longer, and animals do not move as far downstream in the presence of light. Compared with untreated tadpoles tested in the dark, tadpoles exposed to gentamicin show less accurate rheotaxis with longer latency and do not move as far downstream in response to flow. These effects are compounded by the presence of light cues. The disruptive effects of light on flow sensing in Xenopus emphasize the disturbances to natural behaviors that may be produced by anthropogenic illumination in nocturnal habitats.
Heat loss in air of an Antarctic marine mammal, the Weddell seal
Venue: Journal of Comparative Physiology B

The conflicting needs of homeostasis in air versus water complicate our understanding of thermoregulation in marine mammals. Large-scale modeling efforts directed at predicting the energetic impact of changing sea ice conditions on polar ecosystems require a better understanding of thermoregulation in air of free-ranging animals. We utilized infrared imaging as an indirect approach to determine surface temperatures of dry, hauled-out Weddell seals (Leptonychotes weddellii, n = 35) of varying age and body condition during the Antarctic summer. The study groups provided a fivefold range in body mass and a threefold range in blubber depth. Surface temperature (Ts) did not vary by body region (head, shoulder, axilla, torso, hip, flippers). Average seal Ts (mean 13.9 ± 11.2 °C) was best described through a combination of the physical traits of body mass and environmental variables of ambient temperature Tair, and wind speed. Additional factors of ice temperature (Tice), relative humidity and cloud cover did not improve the model. Heat transfer model estimates suggested that radiation contributed 56.6 ± 7.7 % of total heat loss. Convection and conduction accounted for the remaining 15.7 ± 12.3 and 27.7 ± 9.3 %, respectively. Heat loss by radiation was primarily influenced by body mass and wind speed, whereas convective heat loss was influenced primarily by blubber depth and wind speed. Conductive heat loss was modeled largely as a function of physical traits of mass and blubber depth rather than any environmental covariates, and therefore was substantially higher in animals in leaner condition.
Sex differences in the long-term repeatability of the acute stress response in long-lived, free-living Florida scrub-jays (Aphelocoma coerulescens)
Venue: Journal of Comparative Physiology B

There is increasing evidence that individual differences in the physiological stress response are persistent traits in many animals. To test the hypothesis that the stress-induced CORT (SI-CORT) response is repeatable over the adult life span of Florida scrub-jays (Aphelocoma coerulescens), we sampled 32 male and 25 female free-living scrub-jays (aged 2–13 years) during a 9-year period (2004–2012). Each individual was sampled two to five times and samples were collected one or more years apart during the pre-breeding season (Jan–March). In addition, individuals sampled over the greatest time period (6–8 years) were analyzed separately to more closely assess long-term repeatability. SI-CORT was repeatable in females, but not males, when values were not corrected for confounding variables (agreement repeatability). However, when the year and time of day of sample collection were controlled (adjusted repeatability), SI-CORT was repeatable in both sexes. SI-CORT was also repeatable in the males and females sampled 6–8 years apart. Finally, baseline CORT levels of males, but not females, exhibited low but significant repeatability when adjusted for year. The results of this study demonstrate that differences in SI-CORT levels were repeatable within adult scrub-jays sampled up to 8 years apart. Further, the female SI-CORT response was more consistent between pre-breeding seasons than males, which may have resulted from males having higher SI-CORT plasticity in response to environmental conditions. These data support the hypothesis that the SI-CORT response of Florida scrub-jays develops before adulthood and persists throughout much, if not all, of their natural adult life span.
Oxygen-induced plasticity in tracheal morphology and discontinuous gas exchange cycles in cockroaches Nauphoeta cinerea
Venue: Journal of Comparative Physiology B

The function and mechanism underlying discontinuous gas exchange in terrestrial arthropods continues to be debated. Three adaptive hypotheses have been proposed to explain the evolutionary origin or maintenance of discontinuous gas exchange cycles (DGCs), which may have evolved to reduce respiratory water loss, facilitate gas exchange in high CO2 and low O2 micro-environments, or to ameliorate potential damage as a result of oversupply of O2. None of these hypotheses have unequivocal support, and several non-adaptive hypotheses have also been proposed. In the present study, we reared cockroaches Nauphoeta cinerea in selected levels of O2 throughout development, and examined how this affected growth rate, tracheal morphology and patterns of gas exchange. O2 level in the rearing environment caused significant changes in tracheal morphology and the exhibition of DGCs, but the direction of these effects was inconsistent with all three adaptive hypotheses: water loss was not associated with DGC length, cockroaches grew fastest in hyperoxia, and DGCs exhibited by cockroaches reared in normoxia were shorter than those exhibited by cockroaches reared in hypoxia or hyperoxia.
Nycthemeral variation in melatonin receptor expression in the lymphoid organs of a tropical seasonal breeder Funambulus pennanti
Venue: Journal of Comparative Physiology A

Seasonal variations in immune functions point toward the involvement of melatonin in its regulation. These chronobiotic effects are exerted by receptors present on the immunocompetent cells. The present study investigated daily/nycthemeral variation in expression of melatonin receptor subtypes MT1/MT2 in the lymphoid organs (spleen/thymus) of a tropical squirrel, Funambulus pennanti. The receptor expression was noted every 4 h interval over 24 h under natural light–dark cycle, during two seasons and was correlated with peripheral level of melatonin. The MT1/MT2 receptor expression displayed higher levels at the time of dusk (light–dark transition; 1800 hours), while plasma melatonin was still low compared to the preceding time point. The receptors were downregulated during the nighttime with a minimum expression at 0200 hours. Thymus, during the long day length, showed a tissue-specific pattern of receptor expression with a minimum expression at 0600 hours. Results suggest that photoperiod by modulation of melatonin level inversely regulates the receptor expression. The observations imply that there exists a temporal window of sensitivity in the target organs to the melatonin signal that is regulated by modulation of melatonin receptor expression which might be involved in mediating the photoperiodic effects of melatonin in the control of seasonal immune physiology.
Parasitoid flies exploiting acoustic communication of insects—comparative aspects of independent functional adaptations
Venue: Journal of Comparative Physiology A

Two taxa of parasitoid Diptera have independently evolved tympanal hearing organs to locate sound producing host insects. Here we review and compare functional adaptations in both groups of parasitoids, Ormiini and Emblemasomatini. Tympanal organs in both groups originate from a common precursor organ and are somewhat similar in morphology and physiology. In terms of functional adaptations, the hearing thresholds are largely adapted to the frequency spectra of the calling song of the hosts. The large host ranges of some parasitoids indicate that their neuronal filter for the temporal patterns of the calling songs are broader than those found in intraspecific communication. For host localization the night active Ormia ochracea and the day active E. auditrix are able to locate a sound source precisely in space. For phonotaxis flight and walking phases are used, whereby O. ochracea approaches hosts during flight while E. auditrix employs intermediate landings and re-orientation, apparently separating azimuthal and vertical angles. The consequences of the parasitoid pressure are discussed for signal evolution and intraspecific communication of the host species. This natural selection pressure might have led to different avoidance strategies in the hosts: silent males in crickets, shorter signals in tettigoniids and fluctuating population abundances in cicadas.
Computational themes of peripheral processing in the auditory pathway of insects
Venue: Journal of Comparative Physiology A

Hearing in insects serves to gain information in the context of mate finding, predator avoidance or host localization. For these goals, the auditory pathways of insects represent the computational substrate for object recognition and localization. Before these higher level computations can be executed in more central parts of the nervous system, the signals need to be preprocessed in the auditory periphery. Here, we review peripheral preprocessing along four computational themes rather than discussing specific physiological mechanisms: (1) control of sensitivity by adaptation, (2) recoding of amplitude modulations of an acoustic signal into a labeled-line code (3) frequency processing and (4) conditioning for binaural processing. Along these lines, we review evidence for canonical computations carried out in the peripheral auditory pathway and show that despite the vast diversity of insect hearing, signal processing is governed by common computational motifs and principles.