Why do sea turtles swim slowly? A metabolic and mechanical approach [RESEARCH ARTICLE]
This study measured the resting metabolic rates and drag coefficients of sea turtles to answer two questions: (1) do turtles swim at the optimal swim speed? and (2) what factors control the optimal swim speed of turtles? The resting metabolic rates of 13 loggerhead and 12 green turtles were measured. Then, the cruising swim speeds of 15 loggerhead and 9 green turtles were measured and their drag coefficients were estimated under natural conditions. The measured cruising swim speeds (0.27–0.50 m s–1) agreed with predicted optimal swim speeds (0.19–0.32 m s–1). The resting metabolic rates of turtles w...
Source: Journal of Experimental Biology - January 12, 2021 Category: Biology Authors: Kinoshita, C., Fukuoka, T., Narazaki, T., Niizuma, Y., Sato, K. Tags: RESEARCH ARTICLE Source Type: research
Effects of variable oxygen regimes on mitochondrial bioenergetics and reactive oxygen species production in a marine bivalve Mya arenaria [RESEARCH ARTICLE]
Natascha Ouillon, Eugene P. Sokolov, Stefan Otto, Gregor Rehder, and Inna M. Sokolova Estuarine and coastal benthic organisms often experience fluctuations in oxygen levels that can negatively impact their mitochondrial function and aerobic metabolism. To study these impacts, we exposed a common sediment-dwelling bivalve, the soft-shell clam Mya arenaria, for 21 days to chronic hypoxia (PO2~4.1 kPa), cyclic hypoxia (PO2~12.7-1.9 kPa, mean=5.7 kPa), or normoxia (PO2~21.1 kPa). pH was manipulated to mimic the covariation in CO2/pH and oxygen levels in coastal hypoxic zones. Mitochondrial respiration, including the proton lea...
Source: Journal of Experimental Biology - January 12, 2021 Category: Biology Authors: Ouillon, N., Sokolov, E. P., Otto, S., Rehder, G., Sokolova, I. M. Tags: RESEARCH ARTICLE Source Type: research
Ontogeny of the star compass in birds: pied flycatchers (Ficedula hypoleuca) can establish the star compass in spring [RESEARCH ARTICLE]
Anna Zolotareva, Gleb Utvenko, Nadezhda Romanova, Alexander Pakhomov, and Nikita Chernetsov The star compass of birds, as well as the sun compass, is not innate. To possess either of them, the birds have to observe the rotating sky and determine its' center of rotation (in the star compass case) or the sun's movement (in the sun compass). Young birds are believed to learn how to use the star compass before their first migration, even though the evidence of this is lacking. Here, we test whether hand-raised Pied flycatchers (Ficedula hypoleuca) which had not established the star compass prior to their first autumn migration...
Source: Journal of Experimental Biology - January 12, 2021 Category: Biology Authors: Zolotareva, A., Utvenko, G., Romanova, N., Pakhomov, A., Chernetsov, N. Tags: RESEARCH ARTICLE Source Type: research
Multisensory integration supports configural learning of a home refuge in the whip spider Phrynus marginemaculatus [RESEARCH ARTICLE]
Kaylyn A. S. Flanigan, Daniel D. Wiegmann, Eileen A. Hebets, and Verner P. Bingman Whip spiders (Amblypygi) reside in structurally complex habitats and are nocturnally active yet display notable navigational abilities. From the theory that uncertainty in sensory inputs should promote multisensory representations to guide behavior, we hypothesized that their navigation is supported by a multisensory and perhaps configural representation of navigational inputs, an ability documented in a few insects and never reported in arachnids. We trained Phrynus marginemaculatus to recognize a home shelter characterized by both discrimi...
Source: Journal of Experimental Biology - January 12, 2021 Category: Biology Authors: Flanigan, K. A. S., Wiegmann, D. D., Hebets, E. A., Bingman, V. P. Tags: RESEARCH ARTICLE Source Type: research
2020 - A year of changes, challenges and opportunities [EDITORIAL]
Craig Franklin (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - January 11, 2021 Category: Biology Authors: Franklin, C. Tags: EDITORIAL Source Type: research
Metabolic cost of freeze-thaw and source of CO2 production in the freeze-tolerant cricket Gryllus veletis [RESEARCH ARTICLE]
Adam Smith, Kurtis F. Turnbull, Julian H. Moulton, and Brent J. Sinclair
Freeze-tolerant insects can survive the conversion of a substantial portion of their body water to ice. While the process of freezing induces active responses from some organisms, these responses appear absent from freeze-tolerant insects. Recovery from freezing likely requires energy expenditure to repair tissues and re-establish homeostasis, which should be evident as elevations in metabolic rate after thaw. We measured carbon dioxide (CO2) production in the spring field cricket (Gryllus veletis) as a proxy for metabolic rate during cooling, freezi...
Source: Journal of Experimental Biology - January 11, 2021 Category: Biology Authors: Smith, A., Turnbull, K. F., Moulton, J. H., Sinclair, B. J. Tags: RESEARCH ARTICLE Source Type: research
Cervical air sac oxygen profiles in diving emperor penguins: parabronchial ventilation and the respiratory oxygen store [RESEARCH ARTICLE]
Cassondra L. Williams, Max F. Czapanskiy, Jason S. John, Judy St Leger, Miriam Scadeng, and Paul J. Ponganis
Some marine birds and mammals can perform dives of extraordinary duration and depth. Such dive performance is dependent on many factors, including total body oxygen (O2) stores. For diving penguins, the respiratory system (air sacs and lungs) constitutes 30–50% of the total body O2 store. To better understand the role and mechanism of parabronchial ventilation and O2 utilization in penguins both on the surface and during the dive, we examined air sac partial pressures of O2 (PO2) in emperor penguins (Aptenody...
Source: Journal of Experimental Biology - January 11, 2021 Category: Biology Authors: Williams, C. L., Czapanskiy, M. F., John, J. S., St Leger, J., Scadeng, M., Ponganis, P. J. Tags: RESEARCH ARTICLE Source Type: research
Lung function assessment in the Pacific walrus (Odobenus rosmarus divergens) while resting on land and submerged in water [RESEARCH ARTICLE]
Alicia Borque-Espinosa, Diana Ferrero-Fernandez, Romana Capaccioni-Azzati, and Andreas Fahlman
In the present study, we examined lung function in healthy resting adult (born in 2003) Pacific walruses (Odobenus rosmarus divergens) by measuring respiratory flow (
) using a custom-made pneumotachometer. Three female walruses (670–1025 kg) voluntarily participated in spirometry trials while spontaneously breathing on land (sitting and lying down in sternal recumbency) and floating in water. While sitting, two walruses performed active respiratory efforts, and one animal participated in lung compliance measurements....
Source: Journal of Experimental Biology - January 11, 2021 Category: Biology Authors: Borque-Espinosa, A., Ferrero-Fernandez, D., Capaccioni-Azzati, R., Fahlman, A. Tags: RESEARCH ARTICLE Source Type: research
Are acute and acclimated thermal effects on metabolic rate modulated by cell size? A comparison between diploid and triploid zebrafish larvae [RESEARCH ARTICLE]
Adam Hermaniuk, Iris L. E. van de Pol, and Wilco C. E. P. Verberk
Being composed of small cells may carry energetic costs related to maintaining ionic gradients across cell membranes as well as benefits related to diffusive oxygen uptake. Here, we test the hypothesis that these costs and benefits of cell size in ectotherms are temperature dependent. To study the consequences of cell size for whole-organism metabolic rate, we compared diploid and triploid zebrafish larvae differing in cell size. A fully factorial design was applied combining three different rearing and test temperatures that allowed us to distinguish acute...
Source: Journal of Experimental Biology - January 11, 2021 Category: Biology Authors: Hermaniuk, A., van de Pol, I. L. E., Verberk, W. C. E. P. Tags: RESEARCH ARTICLE Source Type: research
Latencies of mechanically-stimulated escape responses in the Pacific spiny dogfish, Squalus suckleyi [SHORT COMMUNICATION]
Mathias Schakmann, Victoria Becker, Mathias Sogaard, Jacob L. Johansen, John F. Steffensen, and Paolo Domenici Fast escape responses to a predator threat are fundamental to the survival of mobile marine organisms. However, elasmobranchs are often underrepresented in such studies. Here, we measured the escape latency (time interval between the stimulus and first visible reaction) of mechanically-induced escape responses in the Pacific spiny dogfish, Squalus suckleyi, and in two teleosts from the same region, the great sculpin, Myoxocephalus polyacanthocephalus, and the pile perch, Rhacochilus vacca. We found that the dogfis...
Source: Journal of Experimental Biology - January 11, 2021 Category: Biology Authors: Schakmann, M., Becker, V., Sogaard, M., Johansen, J. L., Steffensen, J. F., Domenici, P. Tags: SHORT COMMUNICATION Source Type: research
A novel degree of sex difference in laryngeal physiology of Xenopus muelleri: behavioral and evolutionary implications [RESEARCH ARTICLE]
Kelly E. South, Bernhard Klingenberg, and Elizabeth C. Leininger Characterizing sex and species differences in muscle physiology can contribute to a better understanding of proximate mechanisms underlying behavioral evolution. In Xenopus, the laryngeal muscle's ability to contract rapidly and its electromyogram potentiation allows males to produce calls that are more rapid and intensity-modulated than female calls. Prior comparative studies have shown that some species lacking typical male features of vocalizations sometimes show reduced sex differences in underlying laryngeal physiology. To further understand the evolutio...
Source: Journal of Experimental Biology - January 11, 2021 Category: Biology Authors: South, K. E., Klingenberg, B., Leininger, E. C. Tags: RESEARCH ARTICLE Source Type: research
Does the Preferred Walk-Run Transition Speed on Steep Inclines Minimize Energetic Cost, Heart Rate or Neither? [RESEARCH ARTICLE]
Jackson W. Brill and Rodger Kram Humans prefer to walk at slow speeds and to run at fast speeds. In between, there is a speed at which people choose to transition between gaits, the Preferred Transition Speed (PTS). At slow speeds, it is energetically cheaper to walk and at faster speeds, it is cheaper to run. Thus, there is an intermediate speed, the Energetically Optimal Transition Speed (EOTS). Our goals were to determine: 1) how PTS and EOTS compare across a wide range of inclines and 2) if the EOTS can be predicted by the heart rate optimal transition speed (HROTS). Ten healthy, high-caliber, male trail/mountain runne...
Source: Journal of Experimental Biology - January 11, 2021 Category: Biology Authors: Brill, J. W., Kram, R. Tags: RESEARCH ARTICLE Source Type: research
High spatial resolution mapping of the mucosal proteome of the gills of Crassostrea virginica: implication in particle processing [RESEARCH ARTICLE]
Emmanuelle Pales Espinosa and Bassem Allam In the oyster Crassostrea virginica, the organization of the gill allows bidirectional particle transport where a dorsal gill tract directs particles meant to be ingested while a ventral tract collects particles intended to be rejected as pseudofeces. Previous studies showed that the transport of particles in both tracts is mediated by mucus. Consequently, we hypothesized that the nature and/or the quantity of mucosal proteins present in each tract is likely different. Using endoscopy-aided micro-sampling of mucus from each tract followed by multidimensional protein identification...
Source: Journal of Experimental Biology - January 11, 2021 Category: Biology Authors: Pales Espinosa, E., Allam, B. Tags: RESEARCH ARTICLE Source Type: research
Symbiont regulation in Stylophora pistillata during cold stress: an acclimation mechanism against oxidative stress and severe bleaching [RESEARCH ARTICLE]
This study assessed how short and long cold excursions in seawater temperature affect the physiology and biochemical processes related to oxidative stress in the reef-building coral Stylophora pistillata. We provide for the first time direct evidence that the mechanisms underpinning cold stress and bleaching are related to the production of reactive oxygen species (ROS), and that rapid expulsion of a significant proportion of the symbiont population by the host during cooling conditions is an acclimation mechanism to avoid oxidative stress, and ultimately severe bleaching. Furthermore, this study is one of the first to sho...
Source: Journal of Experimental Biology - January 11, 2021 Category: Biology Authors: de Barros Marangoni, L. F., Rottier, C., Ferrier-Pages, C. Tags: RESEARCH ARTICLE Source Type: research
Motion parallax via head movements modulates visuo-motor control in pigeons [RESEARCH ARTICLE]
This study investigated whether self-generated motion parallax modulates pecking motor control and visual size perception in pigeons (Columba livia). We trained pigeons to peck a target on a touch monitor and to classify it as small or large. To manipulate motion parallax of the target, we changed the target position on the monitor according to the bird's head position in real time using a custom-built head tracker with two cameras. Pecking motor control was affected by the manipulation of motion parallax: when the motion-parallax signified the target position farther than the monitor surface, the head position just before...
Source: Journal of Experimental Biology - January 11, 2021 Category: Biology Authors: Hataji, Y., Kuroshima, H., Fujita, K. Tags: RESEARCH ARTICLE Source Type: research
