Forelimb position affects facultative bipedal locomotion in lizards [RESEARCH ARTICLE]
This study quantified the frequency of bipedalism when sprinting with versus without an obstacle at 0.8 m from the start of a sprint. Forelimb positions were quantified during bipedal running at the start of a sprint and when crossing an obstacle. Two species with contrasting body forms (and thus different BCoM) were studied (Sceloporus woodi and Aspidoscelis sexlineata) to assess potential variation due to body plan and obstacle-crossing behavior. No significant difference in frequency of bipedalism was observed in S. woodi with or without an obstacle. However, A. sexlineata primarily used a bipedal posture when spri...
Source: Journal of Experimental Biology - December 12, 2018 Category: Biology Authors: Kinsey, C. T., McBrayer, L. D. Tags: Comparative biomechanics of movement RESEARCH ARTICLE Source Type: research

Unraveling inter-species differences in hagfish slime skein deployment [RESEARCH ARTICLE]
Mark A. Bernards Jr, Sarah Schorno, Evan McKenzie, Timothy M. Winegard, Isdin Oke, David Plachetzki, and Douglas S. Fudge Hagfishes defend themselves from fish predators by producing defensive slime consisting of mucous and thread components that interact synergistically with seawater to pose a suffocation risk to their attackers. Deployment of the slime occurs in a fraction of a second and involves hydration of mucous vesicles as well as unraveling of the coiled threads to their full length of ~150 mm. Previous work showed that unraveling of coiled threads (or ‘skeins’) in Atlantic hagfish requires vigor...
Source: Journal of Experimental Biology - December 12, 2018 Category: Biology Authors: Bernards, M. A., Schorno, S., McKenzie, E., Winegard, T. M., Oke, I., Plachetzki, D., Fudge, D. S. Tags: RESEARCH ARTICLE Source Type: research

Sauntering macaques: not walking but running [INSIDE JEB]
Kathryn Knight (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - December 10, 2018 Category: Biology Authors: Knight, K. Tags: INSIDE JEB Source Type: research

Contraction speed and type influences rapid utilisation of available muscle force: neural and contractile mechanisms [RESEARCH ARTICLE]
This study investigated the influence of contraction speed and type on the human ability to rapidly increase torque and utilise the available maximum voluntary torque (MVT) as well as the neuromuscular mechanisms underpinning any effects. Fifteen young, healthy males completed explosive voluntary knee extensions in five conditions: isometric (ISO), and both concentric and eccentric at two constant accelerations of 500 deg s–2 (CONSLOW and ECCSLOW) and 2000 deg s–2 (CONFAST and ECCFAST). Explosive torque and quadriceps EMG were recorded every 25 ms up to 150 ms from their respective...
Source: Journal of Experimental Biology - December 10, 2018 Category: Biology Authors: Tillin, N. A., Pain, M. T. G., Folland, J. P. Tags: Comparative biomechanics of movement RESEARCH ARTICLE Source Type: research

Food dissemination in ants: robustness of the trophallactic network against resource quality [SHORT COMMUNICATION]
Olivier Bles, Jean-Louis Deneubourg, and Stamatios C. Nicolis Insect societies are often composed of many individuals, achieving collective decisions that depend on environmental and colonial characteristics. For example, ants are able to focus their foraging effort on the most rewarding food source. While this phenomenon is well known, the link between the food source quality and the intranidal food dissemination networks and its dynamics has been neglected. Here, we analysed the global dynamics of food dissemination in Camponotus cruentatus workers, after feeding on a low (0.1 mol l–1) or on a high (1&nb...
Source: Journal of Experimental Biology - December 10, 2018 Category: Biology Authors: Bles, O., Deneubourg, J.-L., Nicolis, S. C. Tags: SHORT COMMUNICATION Source Type: research

Three-dimensional shape and velocity changes affect responses of a locust visual interneuron to approaching objects [RESEARCH ARTICLE]
Tarquin P. Stott, Erik G. N. Olson, Rachel H. Parkinson, and John R. Gray Adaptive collision avoidance behaviours require accurate detection of complex spatiotemporal properties of an object approaching in an animal's natural, three-dimensional environment. Within the locust, the lobula giant movement detector and its postsynaptic partner, the descending contralateral movement detector (DCMD), respond robustly to images that emulate an approaching two-dimensional object and exhibit firing rate modulation correlated with changes in object trajectory. It is not known how this pathway responds to visual expansion of a three-...
Source: Journal of Experimental Biology - December 10, 2018 Category: Biology Authors: Stott, T. P., Olson, E. G. N., Parkinson, R. H., Gray, J. R. Tags: Neuroethology RESEARCH ARTICLE Source Type: research

Ascending flight and decelerating vertical glides in Anna's hummingbirds [RESEARCH ARTICLE]
Victor Manuel Ortega-Jimenez and Robert Dudley Hummingbirds are observationally well known for their capacity to vertically ascend whilst hovering, but the underlying mechanics and possible energetic limits to ascent rates are unclear. Decelerations during vertical ascent to a fixed target may also be associated with specific visual responses to regulate the body's trajectory. Here, we studied climbing flight and subsequent deceleration in male Anna's hummingbirds (Calypte anna) over an approximately 2 m vertical distance. Birds reached vertical speeds and accelerations up to ~4 m s–1 and 10 m s&...
Source: Journal of Experimental Biology - December 10, 2018 Category: Biology Authors: Ortega-Jimenez, V. M., Dudley, R. Tags: Comparative biomechanics of movement RESEARCH ARTICLE Source Type: research

Echo interval and not echo intensity drives bat flight behavior in structured corridors [RESEARCH ARTICLE]
Michaela Warnecke, Silvio Macias, Benjamin Falk, and Cynthia F. Moss To navigate in the natural environment, animals must adapt their locomotion in response to environmental stimuli. The echolocating bat relies on auditory processing of echo returns to represent its surroundings. Recent studies have shown that echo flow patterns influence bat navigation, but the acoustic basis for flight path selection remains unknown. To investigate this problem, we released bats in a flight corridor with walls constructed of adjacent individual wooden poles, which returned cascades of echoes to the flying bat. We manipulated the spacing...
Source: Journal of Experimental Biology - December 10, 2018 Category: Biology Authors: Warnecke, M., Macias, S., Falk, B., Moss, C. F. Tags: Neuroethology RESEARCH ARTICLE Source Type: research

High-frequency temperature variability mirrors fixed differences in thermal limits of the massive coral Porites lobata [RESEARCH ARTICLE]
Daniel J. Barshis, Charles Birkeland, Robert J. Toonen, Ruth D. Gates, and Jonathon H. Stillman Spatial heterogeneity in environmental characteristics can drive adaptive differentiation when contrasting environments exert divergent selection pressures. This environmental and genetic heterogeneity can substantially influence population and community resilience to disturbance events. Here, we investigated corals from the highly variable back-reef habitats of Ofu Island in American Samoa that thrive in thermal conditions known to elicit widespread bleaching and mortality elsewhere. To investigate the relative importance of a...
Source: Journal of Experimental Biology - December 10, 2018 Category: Biology Authors: Barshis, D. J., Birkeland, C., Toonen, R. J., Gates, R. D., Stillman, J. H. Tags: Ecophysiology: responses to environmental stressors and change RESEARCH ARTICLE Source Type: research

Global dynamics of bipedal macaques during grounded and aerial running [RESEARCH ARTICLE]
Reinhard Blickhan, Emanuel Andrada, Eishi Hirasaki, and Naomichi Ogihara Macaques trained to perform bipedally use grounded running, skipping and aerial running, but avoid walking. The preference for grounded running across a wide range of speeds is substantially different from the locomotion habits observed in humans, which may be the result of differences in leg compliance. In the present study, based on kinematic and dynamic observations of three individuals crossing an experimental track, we investigated global leg properties such as leg stiffness and viscous damping during grounded and aerial running. We found that, ...
Source: Journal of Experimental Biology - December 10, 2018 Category: Biology Authors: Blickhan, R., Andrada, E., Hirasaki, E., Ogihara, N. Tags: RESEARCH ARTICLE Source Type: research

Hunting in archerfish - an ecological perspective on a remarkable combination of skills [REVIEW]
Stefan Schuster Archerfish are well known for using jets of water to dislodge distant aerial prey from twigs or leaves. This Review gives a brief overview of a number of skills that the fish need to secure prey with their shooting technique. Archerfish are opportunistic hunters and, even in the wild, shoot at artificial objects to determine whether these are rewarding. They can detect non-moving targets and use efficient search strategies with characteristics of human visual search. Their learning of how to engage targets can be remarkably efficient and can show impressive degrees of generalization, including learning fro...
Source: Journal of Experimental Biology - December 10, 2018 Category: Biology Authors: Schuster, S. Tags: Neuroethology REVIEW Source Type: research

Do arthropods feel anxious during molts? [SHORT COMMUNICATION]
Julien Bacque-Cazenave, Marion Berthomieu, Daniel Cattaert, Pascal Fossat, and Jean Paul Delbecque The molting process of arthropods, chiefly controlled by ecdysteroids, is generally considered very stressful. Our previous investigations have shown that crayfish, after having experienced stressing situations, display anxiety-like behavior (ALB), characterized by aversion to light in a dark/light plus-maze (DLPM). In the present experiments, the spontaneous exploratory behavior of isolated crayfish was analyzed in a DLPM at different stages of their molt cycle. All tested animals displayed transitory aversion to light simil...
Source: Journal of Experimental Biology - December 10, 2018 Category: Biology Authors: Bacque-Cazenave, J., Berthomieu, M., Cattaert, D., Fossat, P., Delbecque, J. P. Tags: SHORT COMMUNICATION Source Type: research

Orienting to polarized light at night--matching lunar skylight to performance in a nocturnal beetle [RESEARCH ARTICLE]
James J. Foster, John D. Kirwan, Basil el Jundi, Jochen Smolka, Lana Khaldy, Emily Baird, Marcus J. Byrne, Dan-Eric Nilsson, Sönke Johnsen, and Marie Dacke For polarized light to inform behaviour, the typical range of degrees of polarization observable in the animal's natural environment must be above the threshold for detection and interpretation. Here we present the first investigation of the degree of linear polarization threshold for orientation behaviour in a nocturnal species, with specific reference to the range of degrees of polarization measured in the night sky. An effect of lunar phase on the degree of polariz...
Source: Journal of Experimental Biology - December 10, 2018 Category: Biology Authors: Foster, J. J., Kirwan, J. D., el Jundi, B., Smolka, J., Khaldy, L., Baird, E., Byrne, M. J., Nilsson, D.-E., Johnsen, S., Dacke, M. Tags: RESEARCH ARTICLE Source Type: research

Traction reinforcement in prehensile feet of harvestmen (Arachnida, Opiliones) [RESEARCH ARTICLE]
Jonas O. Wolff, Chantal Wiegmann, Christian S. Wirkner, Alexander Koehnsen, and Stanislav N. Gorb Prehensile and gripping organs are recurring structures in different organisms that enhance friction by the reinforcement and redirection of normal forces. The relationship between organ structure and biomechanical performance is poorly understood, despite a broad relevance for microhabitat choice, movement ecology and biomimetics. Here, we present the first study of the biomechanics of prehensile feet in long-legged harvestmen. These arachnids exhibit the strongest sub-division of legs among arthropods, permitting extreme hyp...
Source: Journal of Experimental Biology - December 10, 2018 Category: Biology Authors: Wolff, J. O., Wiegmann, C., Wirkner, C. S., Koehnsen, A., Gorb, S. N. Tags: RESEARCH ARTICLE Source Type: research

Nitrogen handling in the elasmobranch gut: a role for microbial urease [RESEARCH ARTICLE]
Chris M. Wood, Hon Jung Liew, Gudrun De Boeck, J. Lisa Hoogenboom, and W. Gary Anderson Ureotelic elasmobranchs require nitrogen for both protein growth and urea-based osmoregulation, and therefore are probably nitrogen-limited in nature. Mechanisms exist for retaining and/or scavenging nitrogen at gills, kidney, rectal gland, and gut, but as yet, the latter are not well characterized. Intestinal sac preparations of the Pacific spiny dogfish shark (Squalus acanthias suckleyi) incubated in vitro strongly reabsorbed urea from the lumen after feeding, but mucosal fluid ammonia concentrations increased with incubation time. Ph...
Source: Journal of Experimental Biology - December 10, 2018 Category: Biology Authors: Wood, C. M., Liew, H. J., De Boeck, G., Hoogenboom, J. L., Anderson, W. G. Tags: RESEARCH ARTICLE Source Type: research

Social stress increases plasma cortisol and reduces forebrain cell proliferation in subordinate male zebrafish (Danio rerio) [RESEARCH ARTICLE]
Jonathan Tea, Sarah L. Alderman, and Kathleen M. Gilmour Many animals, including zebrafish (Danio rerio), form social hierarchies through competition for limited resources. Socially subordinate fish may experience chronic stress, leading to prolonged elevation of the glucocorticoid stress hormone cortisol. Since elevated cortisol levels can impair neurogenesis, the present study tested the hypothesis that social stress suppresses cell proliferation in the telencephalon of subordinate zebrafish via a cortisol-mediated mechanism. Cell proliferation was assessed using incorporation of the thymidine analogue, 5-bromo-2'-deoxyu...
Source: Journal of Experimental Biology - December 10, 2018 Category: Biology Authors: Tea, J., Alderman, S. L., Gilmour, K. M. Tags: RESEARCH ARTICLE Source Type: research

Side-swimming plankton snail flaps shell like a fin [INSIDE JEB]
Kathryn Knight (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - December 7, 2018 Category: Biology Authors: Knight, K. Tags: INSIDE JEB Source Type: research

Using a shell as a wing: pairing of dissimilar appendages in atlantiid heteropod swimming [SHORT COMMUNICATION]
Ferhat Karakas, Daniel D'Oliveira, Amy E. Maas, and David W. Murphy Atlantiid heteropods are zooplanktonic marine snails which have a calcium carbonate shell and single swimming fin. They actively swim to hunt prey and vertically migrate. Previous accounts of atlantiid heteropod swimming described these animals sculling with the swimming fin while the shell passively hung beneath the body. Here, we show, via high-speed stereophotogrammetric measurements of body, fin and shell kinematics, that the atlantiid heteropod Atlanta selvagensis actively flaps both the swimming fin and shell in a highly coordinated wing-like manner...
Source: Journal of Experimental Biology - December 7, 2018 Category: Biology Authors: Karakas, F., D'Oliveira, D., Maas, A. E., Murphy, D. W. Tags: SHORT COMMUNICATION Source Type: research

Porpoises have higher metabolic rates than thought to keep warm in cold water [INSIDE JEB]
Kathryn Knight (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - December 6, 2018 Category: Biology Authors: Knight, K. Tags: INSIDE JEB Source Type: research

High field metabolic rates of wild harbour porpoises [RESEARCH ARTICLE]
Laia Rojano-Donate, Birgitte I. McDonald, Danuta M. Wisniewska, Mark Johnson, Jonas Teilmann, Magnus Wahlberg, Jakob Hojer-Kristensen, and Peter T. Madsen Reliable estimates of field metabolic rates (FMRs) in wild animals are essential for quantifying their ecological roles, as well as for evaluating fitness consequences of anthropogenic disturbances. Yet, standard methods for measuring FMR are difficult to use on free-ranging cetaceans whose FMR may deviate substantially from scaling predictions using terrestrial mammals. Harbour porpoises (Phocoena phocoena) are among the smallest marine mammals, and yet they live in co...
Source: Journal of Experimental Biology - December 6, 2018 Category: Biology Authors: Rojano-Donate, L., McDonald, B. I., Wisniewska, D. M., Johnson, M., Teilmann, J., Wahlberg, M., Hojer-Kristensen, J., Madsen, P. T. Tags: RESEARCH ARTICLE Source Type: research

Distinct metabolic adjustments arise from acclimation to constant hypoxia and intermittent hypoxia in estuarine killifish (Fundulus heteroclitus) [RESEARCH ARTICLE]
We examined how killifish adjust O2 supply and demand during acute hypoxia, and how these responses are altered after prolonged acclimation to constant or intermittent patterns of hypoxia exposure. We acclimated killifish to normoxia (~20 kPa O2), constant hypoxia (2 kPa) or intermittent cycles of nocturnal hypoxia (12 h:12 h normoxia:hypoxia) for 28 days, and then compared whole-animal O2 consumption rates (MO2) and tissue metabolites during exposure to 12 h of hypoxia followed by reoxygenation in normoxia. Normoxia-acclimated fish experienced a pronounced 27% drop in MO2 during acu...
Source: Journal of Experimental Biology - December 5, 2018 Category: Biology Authors: Borowiec, B. G., McClelland, G. B., Rees, B. B., Scott, G. R. Tags: RESEARCH ARTICLE Source Type: research

An attempt to select non-genetic variation in resistance to starvation and reduced chill coma recovery time in Drosophila melanogaster [RESEARCH ARTICLE]
Bianca F. Menezes, Judit Salces-Ortiz, Heloïse Muller, Nelly Burlet, Sonia Martinez, Marie Fablet, and Cristina Vieira Phenotypic variance is attributed to genetic and non-genetic factors, and only the former are presumed to be inherited and thus suitable for the action of selection. Although increasing amounts of data suggest that non-genetic variability may be inherited, we have limited empirical data in animals. Here, we performed an artificial selection experiment using Drosophila melanogaster inbred lines. We quantified the response to selection for a decrease in chill coma recovery time and an increase in starvati...
Source: Journal of Experimental Biology - December 5, 2018 Category: Biology Authors: Menezes, B. F., Salces-Ortiz, J., Muller, H., Burlet, N., Martinez, S., Fablet, M., Vieira, C. Tags: RESEARCH ARTICLE Source Type: research

Innate visual preferences and behavioral flexibility in Drosophila [RESEARCH ARTICLE]
Martyna J. Grabowska, James Steeves, Julius Alpay, Matthew Van De Poll, Deniz Ertekin, and Bruno van Swinderen Visual decision making in animals is influenced by innate preferences as well as experience. Interaction between hard-wired responses and changing motivational states determines whether a visual stimulus is attractive, aversive or neutral. It is, however, difficult to separate the relative contribution of nature versus nurture in experimental paradigms, especially for more complex visual parameters such as the shape of objects. We used a closed-loop virtual reality paradigm for walking Drosophila to uncover innat...
Source: Journal of Experimental Biology - December 5, 2018 Category: Biology Authors: Grabowska, M. J., Steeves, J., Alpay, J., Van De Poll, M., Ertekin, D., van Swinderen, B. Tags: RESEARCH ARTICLE Source Type: research

Hif-1{alpha} paralogs play a role in the hypoxic ventilatory response of larval and adult zebrafish (Danio rerio) [RESEARCH ARTICLE]
Milica Mandic, Velislava Tzaneva, Vincent Careau, and Steve F. Perry Hypoxia inducible factor (Hif) 1α, an extensively studied transcription factor, is involved in the regulation of many biological processes in hypoxia including the hypoxic ventilatory response. In zebrafish, there are two paralogs of Hif-1α (Hif-1A and Hif-1B), but little is known about the specific roles or potential sub-functionalization of the paralogs in response to hypoxia. Using knockout lines of Hif-1α paralogs, we examined their involvement in the hypoxic ventilatory response, measured as ventilation frequency (fV) in larval and ...
Source: Journal of Experimental Biology - December 5, 2018 Category: Biology Authors: Mandic, M., Tzaneva, V., Careau, V., Perry, S. F. Tags: RESEARCH ARTICLE Source Type: research

How do baleen whales stow their filter? A comparative biomechanical analysis of baleen bending [RESEARCH ARTICLE]
Alexander J. Werth, Diego Rita, Michael V. Rosario, Michael J. Moore, and Todd L. Sformo Bowhead and right whale (balaenid) baleen filtering plates, longer in vertical dimension (≥3–4 m) than the closed mouth, presumably bend during gape closure. This has not been observed in live whales, even with scrutiny of video-recorded feeding sequences. To determine what happens to the baleen during gape closure, we conducted an integrative, multifactorial study including materials testing, functional (flow tank and kinematic) testing and histological examination. We measured baleen bending properties along the dorsov...
Source: Journal of Experimental Biology - December 4, 2018 Category: Biology Authors: Werth, A. J., Rita, D., Rosario, M. V., Moore, M. J., Sformo, T. L. Tags: RESEARCH ARTICLE Source Type: research

Bite force and cranial bone strain in four species of lizards [RESEARCH ARTICLE]
Callum F. Ross, Laura B. Porro, Anthony Herrel, Susan E. Evans, and Michael J. Fagan In vivo bone strain data provide direct evidence of strain patterns in the cranium during biting. Compared with those in mammals, in vivo bone strains in lizard skulls are poorly documented. This paper presents strain data from the skulls of Anolis equestris, Gekko gecko, Iguana iguana and Salvator merianae during transducer biting. Analysis of variance was used to investigate effects of bite force, bite point, diet, cranial morphology and cranial kinesis on strain magnitude. Within individuals, the most consistent determinants of varianc...
Source: Journal of Experimental Biology - December 4, 2018 Category: Biology Authors: Ross, C. F., Porro, L. B., Herrel, A., Evans, S. E., Fagan, M. J. Tags: RESEARCH ARTICLE Source Type: research

Deciphering function of the pulmonary arterial sphincters in loggerhead sea turtles (Caretta caretta) [RESEARCH ARTICLE]
Daniel Garcia-Parraga, Teresa Lorenzo, Tobias Wang, Jose-Luis Ortiz, Joaquin Ortega, Jose-Luis Crespo-Picazo, Julio Cortijo, and Andreas Fahlman To provide new insight into the pathophysiological mechanisms underlying gas emboli (GE) in bycaught loggerhead sea turtles (Caretta caretta), we investigated the vasoactive characteristics of the pulmonary and systemic arteries, and the lung parenchyma (LP). Tissues were opportunistically excised from recently dead animals for in vitro studies of vasoactive responses to four different neurotransmitters: acetylcholine (ACh; parasympathetic), serotonin (5HT), adrenaline (Adr; symp...
Source: Journal of Experimental Biology - December 4, 2018 Category: Biology Authors: Garcia-Parraga, D., Lorenzo, T., Wang, T., Ortiz, J.-L., Ortega, J., Crespo-Picazo, J.-L., Cortijo, J., Fahlman, A. Tags: RESEARCH ARTICLE Source Type: research

Vultures respond to challenges of near-ground thermal soaring by varying bank angle [RESEARCH ARTICLE]
Hannah J. Williams, Olivier Duriez, Mark D. Holton, Giacomo Dell'Omo, Rory P. Wilson, and Emily L. C. Shepard Many large birds rely on thermal soaring flight to travel cross-country. As such, they are under selective pressure to minimise the time spent gaining altitude in thermal updrafts. Birds should be able to maximise their climb rates by maintaining a position close to the thermal core through careful selection of bank angle and airspeed; however, there have been few direct measurements of either parameter. Here, we apply a novel methodology to quantify the bank angles selected by soaring birds using on-board magneto...
Source: Journal of Experimental Biology - December 3, 2018 Category: Biology Authors: Williams, H. J., Duriez, O., Holton, M. D., Dell'Omo, G., Wilson, R. P., Shepard, E. L. C. Tags: RESEARCH ARTICLE Source Type: research

The locomotor kinematics and ground reaction forces of walking giraffes [RESEARCH ARTICLE]
In this study, we examined the stride parameters and ground reaction forces from three adult giraffes in a zoological park, across a range of walking speeds. The patterns of GRFs during walking indicate that giraffes, similar to other mammalian quadrupeds, maintain a forelimb-biased weight distribution. The angular excursion of the neck has functional links with locomotor dynamics in giraffes, and was exaggerated at faster speeds. The horizontal accelerations of the neck and trunk were out of phase, compared with the vertical accelerations which were intermediate between in and out of phase. Despite possessing specialised ...
Source: Journal of Experimental Biology - December 3, 2018 Category: Biology Authors: Basu, C., Wilson, A. M., Hutchinson, J. R. Tags: RESEARCH ARTICLE Source Type: research

Comparison of spatiotemporal gait characteristics between vertical climbing and horizontal walking in primates [RESEARCH ARTICLE]
We examined footfall patterns, diagonality, speed, and stride length in eight species of primates across a range of body masses. We found that during vertical climbing primates slow down, keep more limbs in contact with the substrate at any one time, and increase the frequency of lateral sequence gaits compared to horizontal walking. Taken together these characteristics are assumed to increase stability during locomotion. Phylogenetic relatedness and body size differences have little influence on locomotor patterns observed across species. These data reject the idea that the suite of spatiotemporal gait features observed i...
Source: Journal of Experimental Biology - December 3, 2018 Category: Biology Authors: Granatosky, M. C., Schmitt, D., Hanna, J. Tags: RESEARCH ARTICLE Source Type: research

Interspecific variation in brain mitochondrial complex I and II capacity and ROS emission in marine sculpins [RESEARCH ARTICLE]
Gigi Y. Lau and Jeffrey G. Richards Environmental hypoxia presents a metabolic challenge for animals because it inhibits mitochondrial respiration and can lead to the generation of reactive oxygen species (ROS). We investigated the interplay between O2 use for aerobic respiration and ROS generation among sculpin fishes (Cottidae, Actinopterygii) that are known to vary in whole-animal hypoxia tolerance. We hypothesized that mitochondria from hypoxia tolerant sculpins would show more efficient O2 use with a higher phosphorylation efficiency and lower ROS emission. We showed that brain mitochondria from more hypoxia tolerant ...
Source: Journal of Experimental Biology - December 3, 2018 Category: Biology Authors: Lau, G. Y., Richards, J. G. Tags: RESEARCH ARTICLE Source Type: research

Detailed movement and laterality of fin-biting behaviour with special mouth morphology in Genyochromis mento in Lake Malawi [RESEARCH ARTICLE]
Yuichi Takeuchi, Hiroki Hata, Atsushi Maruyama, Takuto Yamada, Takuma Nishikawa, Makiko Fukui, Richard Zatha, Bosco Rusuwa, and Yoichi Oda Several vertebrates, including fish, exhibit behavioural laterality and associated morphological asymmetry. Laterality may increase individual fitness, and foraging strength, accuracy, and speed. However, little is known about which behaviours are affected by laterality or what fish species exhibit obvious laterality. Previous research on the predatory behaviour of the scale-eating Lake Tanganyika cichlid Perissodus microlepis indicates behavioural laterality that reflects asymmetric ja...
Source: Journal of Experimental Biology - December 3, 2018 Category: Biology Authors: Takeuchi, Y., Hata, H., Maruyama, A., Yamada, T., Nishikawa, T., Fukui, M., Zatha, R., Rusuwa, B., Oda, Y. Tags: RESEARCH ARTICLE Source Type: research

Hydrodynamics of linear acceleration in bluegill sunfish, Lepomis macrochirus [RESEARCH ARTICLE]
In this study, we examined the flow around bluegill sunfish Lepomis macrochirus during steady swimming and during forward acceleration, starting at a range of initial swimming speeds. We found that bluegill produce vortices with higher circulation during acceleration, indicating a higher force per tail beat, but they do not substantially redirect the force. We quantified the flow patterns using high speed video and particle image velocimetry and measured acceleration with small inertial measurement units attached to each fish. Even in steady tail beats, the fish accelerates slightly during each tail beat, and the magnitude...
Source: Journal of Experimental Biology - November 30, 2018 Category: Biology Authors: Wise, T. N., Schwalbe, M. A. B., Tytell, E. D. Tags: Comparative biomechanics of movement RESEARCH ARTICLE Source Type: research

High accuracy at low frequency: detailed behavioural classification from accelerometer data [RESEARCH ARTICLE]
Jack Tatler, Phillip Cassey, and Thomas A. A. Prowse Accelerometers are a valuable tool for studying animal behaviour and physiology where direct observation is unfeasible. However, giving biological meaning to multivariate acceleration data is challenging. Here, we describe a method that reliably classifies a large number of behaviours using tri-axial accelerometer data collected at the low sampling frequency of 1 Hz, using the dingo (Canis dingo) as an example. We used out-of-sample validation to compare the predictive performance of four commonly used classification models (random forest, k-nearest neighbour, supp...
Source: Journal of Experimental Biology - November 29, 2018 Category: Biology Authors: Tatler, J., Cassey, P., Prowse, T. A. A. Tags: RESEARCH ARTICLE Source Type: research

The respiratory mechanics of the yacare caiman (Caiman yacare Daudine) [RESEARCH ARTICLE]
Michelle N. Reichert, Paulo R. C. de Oliveira, George M. P. R. Souza, Henriette G. Moranza, Wilmer A. Z. Restan, Augusto S. Abe, Wilfried Klein, and William K. Milsom The structure and function of crocodilian lungs are unique compared to other reptiles. We examine the extent to which this, and the semi-aquatic lifestyle of crocodilians affect their respiratory mechanics. We measured changes in intratracheal pressure in adult and juvenile caiman (Caiman yacare) during static and dynamic lung volume changes. Respiratory mechanics of juvenile caiman were additionally measured while floating in water and submerged at 30°, ...
Source: Journal of Experimental Biology - November 29, 2018 Category: Biology Authors: Reichert, M. N., de Oliveira, P. R. C., Souza, G. M. P. R., Moranza, H. G., Restan, W. A. Z., Abe, A. S., Klein, W., Milsom, W. K. Tags: RESEARCH ARTICLE Source Type: research

MicroRNAs regulate survival in oxygen-deprived environments [RESEARCH ARTICLE]
Simon G. English, Hanane Hadj-Moussa, and Kenneth B. Storey Some animals must endure prolonged periods of oxygen deprivation to survive. One such extreme model is the northern crayfish (Orconectes virilis), that regularly survives year-round hypoxic and anoxic stresses in its warm stagnant summer waters and in its cold, ice-locked winter waters. To elucidate the molecular underpinnings of anoxia resistance in this natural model, we surveyed the expression profiles of 76 highly conserved microRNAs in crayfish hepatopancreas and tail muscle from normoxic, acute 2 h anoxia, and chronic 20 h anoxia exposures. MicroR...
Source: Journal of Experimental Biology - November 28, 2018 Category: Biology Authors: English, S. G., Hadj-Moussa, H., Storey, K. B. Tags: RESEARCH ARTICLE Source Type: research

Water pH limits extracellular but not intracellular pH compensation in the CO2-tolerant freshwater fish Pangasianodon hypophthalmus [SHORT COMMUNICATION]
Michael A. Sackville, Ryan B. Shartau, Christian Damsgaard, Malthe Hvas, Le My Phuong, Tobias Wang, Mark Bayley, Do Thi Thanh Huong, Nguyen Thanh Phuong, and Colin J. Brauner Preferentially regulating intracellular pH (pHi) confers exceptional CO2 tolerance on fish, but is often associated with reductions in extracellular pH (pHe) compensation. It is unknown whether these reductions are due to intrinsically lower capacities for pHe compensation, hypercarbia-induced reductions in water pH or other factors. To test how water pH affects capacities and strategies for pH compensation, we exposed the CO2-tolerant fish Pangasian...
Source: Journal of Experimental Biology - November 28, 2018 Category: Biology Authors: Sackville, M. A., Shartau, R. B., Damsgaard, C., Hvas, M., Phuong, L. M., Wang, T., Bayley, M., Thanh Huong, D. T., Phuong, N. T., Brauner, C. J. Tags: SHORT COMMUNICATION Source Type: research

Correction: Size-dependent physiological responses of the branching coral Pocillopora verrucosa to elevated temperature and PCO2 (doi:10.1242/jeb.146381) [CORRECTION]
Peter J. Edmunds and Scott C. Burgess (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - November 27, 2018 Category: Biology Authors: Edmunds, P. J., Burgess, S. C. Tags: CORRECTION Source Type: research

Mucky guillemot eggs are definitely not self-cleaning [INSIDE JEB]
Kathryn Knight (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - November 27, 2018 Category: Biology Authors: Knight, K. Tags: INSIDE JEB Source Type: research

Spectral sensitivity in ray-finned fishes: diversity, ecology and shared descent [RESEARCH ARTICLE]
In this study, we examined phylogenetic, physiological and ecological patterns of spectral sensitivity of ray-finned fishes (Actinoptergyii) via a meta-analysis of data compiled from 213 species. Across the fishes sampled, our results indicate that trichromacy is most common, ultraviolet max values are not found in monochromatic or dichromatic species, and increasing chromacy, including from tetra- to pentachromacy, significantly increases spectral sensitivity range. In an ecological analysis, multivariate phylogenetic latent liability modeling was performed to analyze correlations between chromacy and five hypothesized pr...
Source: Journal of Experimental Biology - November 27, 2018 Category: Biology Authors: Schweikert, L. E., Fitak, R. R., Caves, E. M., Sutton, T. T., Johnsen, S. Tags: RESEARCH ARTICLE Source Type: research

Common guillemot (Uria aalge) eggs are not self-cleaning [RESEARCH ARTICLE]
Duncan Jackson, Jamie E. Thompson, Nicola Hemmings, and Timothy R. Birkhead Birds are arguably the most evolutionarily successful extant vertebrate taxon, in part because of their ability to reproduce in virtually all terrestrial habitats. Common guillemots, Uria aalge, incubate their single egg in an unusual and harsh environment; on exposed cliff ledges, without a nest, and in close proximity to conspecifics. As a consequence, the surface of guillemot eggshells is frequently contaminated with faeces, dirt, water and other detritus, which may impede gas exchange or facilitate microbial infection of the developing embryo....
Source: Journal of Experimental Biology - November 27, 2018 Category: Biology Authors: Jackson, D., Thompson, J. E., Hemmings, N., Birkhead, T. R. Tags: RESEARCH ARTICLE Source Type: research

Glucocorticoid-temperature association is shaped by foraging costs in individual zebra finches [SHORT COMMUNICATION]
Blanca Jimeno, Michaela Hau, and Simon Verhulst Glucocorticoid (GC) levels vary with environmental conditions, but the functional interpretation of GC variation remains contentious. A primary function is thought to be metabolic, mobilizing body reserves to match energetic demands. This view is supported by temperature-dependent GC levels, although reports of this effect show unexplained heterogeneity. We hypothesized that the temperature effect on GC concentrations will depend on food availability through its effect on the energy spent to gather the food needed for thermoregulation. We tested this hypothesis in zebra finc...
Source: Journal of Experimental Biology - November 27, 2018 Category: Biology Authors: Jimeno, B., Hau, M., Verhulst, S. Tags: SHORT COMMUNICATION Source Type: research

Serotonin: octopus love potion? [OUTSIDE JEB]
Lauren E. Nadler (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - November 26, 2018 Category: Biology Authors: Nadler, L. E. Tags: OUTSIDE JEB Source Type: research

Adaptive frequency shifts of echolocation sounds in Miniopterus fuliginosus according to the frequency-modulated pattern of jamming sounds [RESEARCH ARTICLE]
In this study, we examined changes in the acoustic characteristics of pulses emitted by Miniopterus fuliginosus while presenting jamming stimuli with different FM patterns to the bat flying alone. Bats significantly altered their TFs when responding to downward (dExp) and upward (uExp) exponential FM sounds as well as to a constant-frequency (CF) stimulus, by approximately 1–2 kHz (dExp: 2.1±0.9 kHz; uExp: 1.7±0.3 kHz; CF: 1.3±0.4 kHz) but not for linear FM sounds. The feature common to the spectra of these three jamming stimuli is a spectrum peak near the TF frequency, demons...
Source: Journal of Experimental Biology - November 26, 2018 Category: Biology Authors: Maitani, Y., Hase, K., Kobayasi, K. I., Hiryu, S. Tags: RESEARCH ARTICLE Source Type: research

High experience levels delay recruitment but promote simultaneous time-memories in honey bee foragers [RESEARCH ARTICLE]
Byron N. Van Nest, Matthew W. Otto, and Darrell Moore Honey bee (Apis mellifera) foragers can remember both the location and time of day food is collected and, even in the absence of a reward, reconnoiter the food source at the appropriate time on subsequent days. This spatiotemporal memory (time-memory) is linked to the circadian clock and enables foragers to synchronize their behavior with floral nectar secretion rhythms, thus eliminating the need to rediscover productive food sources each day. Here, we asked whether the establishment of one time-memory influences the formation of another time-memory at the same time of...
Source: Journal of Experimental Biology - November 26, 2018 Category: Biology Authors: Van Nest, B. N., Otto, M. W., Moore, D. Tags: RESEARCH ARTICLE Source Type: research

Evidence that Rh proteins in the anal papillae of the freshwater mosquito Aedes aegypti are involved in the regulation of acid-base balance in elevated salt and ammonia environments [RESEARCH ARTICLE]
In this study, effects of rearing larvae in salt (5 mmol l–1 NaCl) or ammonia (5 mmol l–1 NH4Cl) on physiological endpoints of ammonia and ion regulation were assessed. In anal papillae of NaCl-reared larvae, Rh protein expression increased, NHE3 transcript abundance decreased and NH4+ excretion increased, and this coincided with decreased hemolymph [NH4+] and pH. We propose that under these conditions, larvae excrete more NH4+ through Rh proteins as a means of eliminating acid from the hemolymph. In anal papillae of NH4Cl-reared larvae, expression of an apical ammonia transporter and the Rh...
Source: Journal of Experimental Biology - November 26, 2018 Category: Biology Authors: Durant, A. C., Donini, A. Tags: RESEARCH ARTICLE Source Type: research

Endotoxin rapidly desensitizes the gonads to kisspeptin-induced luteinizing hormone release in male Siberian hamsters (Phodopus sungorus) [RESEARCH ARTICLE]
In this study, the effects of acute immune activation on the response to kisspeptin were assessed in male Siberian hamsters (Phodopus sungorus). Specifically, an immune response was induced in animals by a single treatment of lipopolysaccharide (LPS), and reproductive hormone concentrations were determined in response to subsequent injections of exogenous kisspeptin. Saline-treated controls showed a robust increase in circulating testosterone in response to kisspeptin; however, this response was blocked in LPS-treated animals. Circulating luteinizing hormone (LH) levels were elevated in response to kisspeptin in both LPS- ...
Source: Journal of Experimental Biology - November 26, 2018 Category: Biology Authors: Long, K. L. P., Bailey, A. M., Greives, T. J., Legan, S. J., Demas, G. E. Tags: RESEARCH ARTICLE Source Type: research

Latency for facultative expression of male-typical courtship behaviour by female bluehead wrasses depends on social rank: the 'priming/gating hypothesis [RESEARCH ARTICLE]
Sarah M. Price, Kyphuong Luong, Rickesha S. Bell, and Gary J. Rose Although socially controlled sex transformation in fishes is well established, the underlying mechanisms are not well understood. Particularly enigmatic is behavioural transformation, in which fish can rapidly switch from exhibiting female to male-typical courtship behaviours following removal of ‘supermales’. Bluehead wrasses are a model system for investigating environmental control of sex determination, particularly the social control of sex transformation. Here, we show that the onset of this behavioural transformation was delayed in female...
Source: Journal of Experimental Biology - November 26, 2018 Category: Biology Authors: Price, S. M., Luong, K., Bell, R. S., Rose, G. J. Tags: Neuroethology RESEARCH ARTICLE Source Type: research

Potential role of the anterior lateral line in sound localization in toadfish (Opsanus tau) [RESEARCH ARTICLE]
Emily A. Cardinal, Craig A. Radford, and Allen F. Mensinger Male oyster toadfish (Opsanus tau) acoustically attract females to nesting sites using a boatwhistle call. The rapid speed of sound underwater combined with the close proximity of the otolithic organs makes inner ear interaural time differences an unlikely mechanism to localize sound. To determine the role that the mechanosensory lateral line may play in sound localization, microwire electrodes were bilaterally implanted into the anterior lateral line nerve to record neural responses to vibrational stimuli. Highest spike rates and strongest phase-locking occurred...
Source: Journal of Experimental Biology - November 26, 2018 Category: Biology Authors: Cardinal, E. A., Radford, C. A., Mensinger, A. F. Tags: RESEARCH ARTICLE Source Type: research

A breath of fresh air for lungless salamanders [OUTSIDE JEB]
William Joyce (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - November 26, 2018 Category: Biology Authors: Joyce, W. Tags: OUTSIDE JEB Source Type: research