Mitochondrial plasticity in the cerebellum of two anoxia-tolerant sharks: contrasting responses to anoxia/reoxygenation [RESEARCH ARTICLE]
Jules B. L. Devaux, Anthony J. R. Hickey, and Gillian M. C. Renshaw Exposure to anoxia leads to rapid ATP depletion, alters metabolic pathways and exacerbates succinate accumulation. Upon re-oxygenation, the preferential oxidation of accumulated succinate most often impairs mitochondrial function. Few species can survive prolonged periods of hypoxia and anoxia at tropical temperatures and those that do may rely on mitochondria plasticity in response to disruptions to oxygen availability. Two carpet sharks, the epaulette shark (Hemiscyllium ocellatum; ES) and the grey carpet shark (Chiloscyllium punctatum; GCS) display diff...
Source: Journal of Experimental Biology - March 4, 2019 Category: Biology Authors: Devaux, J. B. L., Hickey, A. J. R., Renshaw, G. M. C. Tags: RESEARCH ARTICLE Source Type: research

Softness sensing and learning in Drosophila larvae [RESEARCH ARTICLE]
We report that Drosophila larvae can discriminate between different agar concentrations and prefer softer agar. Interestingly, we show that larvae on a harder place search for a softer place using memory associated with an odor and that they evaluate foods by balancing softness and sweetness. These findings suggest that Drosophila larvae integrate mechanosensory information with chemosensory input while foraging. Moreover, we find that the larval preference for softness is affected by genetic background. (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - March 4, 2019 Category: Biology Authors: Kudow, N., Kamikouchi, A., Tanimura, T. Tags: RESEARCH ARTICLE Source Type: research

Regression dilution in energy management patterns [RESEARCH ARTICLE]
Lewis G. Halsey and Andrea Perna Analysis of some experimental biology data involves linear regression and interpretation of the resulting slope value. Usually the x-axis measurements include noise. Noise in the x-variable can create regression dilution, and many biologists are not aware of the implications – regression dilution results in an underestimation of the true slope value. This is particularly problematic when the slope value is diagnostic. For example, energy management strategies of animals can be determined from the regression slope estimate of mean energy expenditure against resting energy expenditure. ...
Source: Journal of Experimental Biology - March 4, 2019 Category: Biology Authors: Halsey, L. G., Perna, A. Tags: RESEARCH ARTICLE Source Type: research

In vivo effects of temperature on the heart and pyloric rhythms in the crab Cancer borealis [RESEARCH ARTICLE]
Dahlia Kushinsky, Ekaterina O. Morozova, and Eve Marder The heart and pyloric rhythms of crustaceans have been studied separately and extensively over many years. Local and hormonal neuromodulation and sensory inputs into these central pattern generator circuits play a significant role in an animal's response to perturbations, but are usually lost or removed during in vitro studies. To examine simultaneously the in vivo motor output of the crustacean heart and pyloric rhythms, we used photoplethysmography. In the population measured (n=49), the heart rhythm frequency ranged from 0.3 to 2.3 Hz. The pyloric rhythm vari...
Source: Journal of Experimental Biology - March 1, 2019 Category: Biology Authors: Kushinsky, D., Morozova, E. O., Marder, E. Tags: RESEARCH ARTICLE Source Type: research

Symmetry breaking and pivotal individuals during the reunification of ant colonies [RESEARCH ARTICLE]
In this study, we found that colonies can reunify even without obvious cues to break the symmetry between sites. To learn how they do so, we observed both symmetric reunifications (between identical nests) and asymmetric reunifications (between nests of unequal quality) by colonies of individually marked ants. Both reunification types were accomplished by a tiny minority that carried nestmates from the ‘losing’ to the ‘winning’ site. Reunification effort was highly skewed in asymmetric splits, where the majority of the work was done by the first ant to transport, which nearly always came from the wi...
Source: Journal of Experimental Biology - March 1, 2019 Category: Biology Authors: Doering, G. N., Pratt, S. C. Tags: RESEARCH ARTICLE Source Type: research

Temperature and external K+ dependence of electrical excitation in ventricular myocytes of cod-like fishes [RESEARCH ARTICLE]
Denis V. Abramochkin, Jaakko Haverinen, Yuri A. Mitenkov, and Matti Vornanen Electrical excitability (EE) is vital for cardiac function and strongly modulated by temperature and external K+ concentration ([K+]o), as formulated in the hypothesis of temperature-dependent deterioration of electrical excitability (TDEE). As little is known about EE of arctic stenothermic fishes, we tested the TDEE hypothesis on ventricular myocytes of polar cod (Boreogadus saida) and navaga (Eleginus nawaga) of the Arctic Ocean and those of temperate freshwater burbot (Lota lota). Ventricular action potentials (APs) were elicited in current-c...
Source: Journal of Experimental Biology - March 1, 2019 Category: Biology Authors: Abramochkin, D. V., Haverinen, J., Mitenkov, Y. A., Vornanen, M. Tags: RESEARCH ARTICLE Source Type: research

Skeletal kinematics of the hyoid arch in the suction-feeding shark Chiloscyllium plagiosum [RESEARCH ARTICLE]
Bradley Scott, Cheryl A. D. Wilga, and Elizabeth L. Brainerd White-spotted bamboo sharks, Chiloscyllium plagiosum, generate strong suction-feeding pressures that rival the highest levels measured in ray-finned fishes. However, the hyostylic jaw suspension of these sharks is fundamentally different from the actinopterygian mechanism, including more mobile hyomandibulae, with the jaws and ceratohyal suspended from the hyomandibulae. Prior studies have proposed skeletal kinematics during feeding in orectolobid sharks from indirect measurements. Here, we tested these hypotheses using XROMM to measure cartilage motions directl...
Source: Journal of Experimental Biology - March 1, 2019 Category: Biology Authors: Scott, B., Wilga, C. A. D., Brainerd, E. L. Tags: Comparative biomechanics of movement RESEARCH ARTICLE Source Type: research

Parenting is hot work for blue tits [OUTSIDE JEB]
William Joyce (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - March 1, 2019 Category: Biology Authors: Joyce, W. Tags: OUTSIDE JEB Source Type: research

Sex makes Mongolian gerbils better dads [OUTSIDE JEB]
Gina Mantica (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - March 1, 2019 Category: Biology Authors: Mantica, G. Tags: OUTSIDE JEB Source Type: research

How Kermit got streetwise [OUTSIDE JEB]
Daniel E. Rozen (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - March 1, 2019 Category: Biology Authors: Rozen, D. E. Tags: OUTSIDE JEB Source Type: research

Stretch-induced force bursts simplify stick insects leg swing [OUTSIDE JEB]
Jan Stenum (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - March 1, 2019 Category: Biology Authors: Stenum, J. Tags: OUTSIDE JEB Source Type: research

Gut microbiota affects development and olfactory behavior in Drosophila melanogaster [RESEARCH ARTICLE]
Huili Qiao, Ian W. Keesey, Bill S. Hansson, and Markus Knaden It has been shown that gut microbes are very important for the behavior and development of Drosophila, as the beneficial microbes are involved in the identification of suitable feeding and egg-laying locations. However, in what way these associated gut microbes influence the fitness-related behaviors of Drosophila melanogaster remains unclear. Here, we show that D. melanogaster exhibits different behavioral preferences towards gut microbes. Both adults and larvae were attracted by the volatile compounds of Saccharomyces cerevisiae and Lactobacillus plantarum, b...
Source: Journal of Experimental Biology - March 1, 2019 Category: Biology Authors: Qiao, H., Keesey, I. W., Hansson, B. S., Knaden, M. Tags: RESEARCH ARTICLE Source Type: research

Encoding phase spectrum for evaluating 'electric qualia [RESEARCH ARTICLE]
This article concerns the role of electroreceptor phase sensitivity in American pulse Gymnotiformes. These fish show electroreceptors sharply tuned to narrow frequency bands. This led to the common thought that most electrosensory information is contained in the amplitude spectra of the signals. However, behavioral and modeling studies suggest that in their pulses, Gymnotiformes electroreceptors also encode cues embodied in the phase spectrum of natural stimuli. Here, we show that the two main types of tuberous primary afferents of Gymnotus omarorum differentially respond to cues embodied in the amplitude and phase spectra...
Source: Journal of Experimental Biology - March 1, 2019 Category: Biology Authors: Caputi, A. A., Aguilera, P. A. Tags: RESEARCH ARTICLE Source Type: research

Do the relationships between hindlimb anatomy and sprint speed variation differ between sexes in Anolis lizards? [RESEARCH ARTICLE]
Aurelien Lowie, Elisa Gillet, Bieke Vanhooydonck, Duncan J. Irschick, Jonathan B. Losos, and Anthony Herrel The ability of an animal to run fast has important consequences on its survival capacity and overall fitness. Previous studies have documented how variation in the morphology of the limbs is related to variation in locomotor performance. Although these studies have suggested direct relations between sprint speed and hindlimb morphology, few quantitative data exist. Consequently, it remains unclear whether selection acts in limb segment lengths, overall muscle mass or muscle architecture (e.g. muscle fiber length and...
Source: Journal of Experimental Biology - March 1, 2019 Category: Biology Authors: Lowie, A., Gillet, E., Vanhooydonck, B., Irschick, D. J., Losos, J. B., Herrel, A. Tags: Comparative biomechanics of movement RESEARCH ARTICLE Source Type: research

Parasitic gut infection in Libellula pulchella causes functional and molecular resemblance of dragonfly flight muscle to skeletal muscle of obese vertebrates [RESEARCH ARTICLE]
Rudolf J. Schilder and Hannah Stewart We previously demonstrated the existence of a naturally occurring metabolic disease phenotype in Libellula pulchella dragonflies that shows high similarity to vertebrate obesity and type II diabetes, and is caused by a protozoan gut parasite. To further mechanistic understanding of how this metabolic disease phenotype affects fitness of male L. pulchella in vivo, we examined infection effects on in situ muscle performance and molecular traits relevant to dragonfly flight performance in nature. Importantly, these traits were previously shown to be affected in obese vertebrates. Similar...
Source: Journal of Experimental Biology - March 1, 2019 Category: Biology Authors: Schilder, R. J., Stewart, H. Tags: RESEARCH ARTICLE Source Type: research

Flight muscle protein damage during endurance flight is related to energy expenditure but not dietary polyunsaturated fatty acids in a migratory bird [RESEARCH ARTICLE]
We examined how flight muscles manage oxidative stress during flight, and whether dietary long-chain PUFA influence ROS management or damage. Yellow-rumped warblers were fed diets low in PUFA, or high in long-chain n-3 or n-6 PUFA. Flight muscle was sampled from birds in each diet treatment at rest or immediately after flying for up to a maximum of 360 min in a wind tunnel. Flight increased flight muscle superoxide dismutase activity but had no effect on catalase activity. The ratio of glutathione to glutathione disulphide decreased during flight. Oxidative protein damage, indicated by protein carbonyls, increased wit...
Source: Journal of Experimental Biology - March 1, 2019 Category: Biology Authors: Dick, M. F., Guglielmo, C. G. Tags: RESEARCH ARTICLE Source Type: research

Adult diet of a tephritid fruit fly does not compensate for impact of a poor larval diet on stress resistance [RESEARCH ARTICLE]
Christopher W. Weldon, Sandiso Mnguni, Fabien Demares, Esther E. du Rand, Kevin Malod, Aruna Manrakhan, and Susan W. Nicolson Adult holometabolous insects may derive metabolic resources from either larval or adult feeding, but little is known of whether adult diets can compensate for deficiencies in the larval diet in terms of stress resistance. We investigated how stress resistance is affected and compensated for by diet across life stages in the marula fruit fly, Ceratitis cosyra (Walker) (Diptera: Tephritidae). Larvae were fed diets containing either 8% torula yeast, the standard diet used to rear this species, or 1% ye...
Source: Journal of Experimental Biology - February 28, 2019 Category: Biology Authors: Weldon, C. W., Mnguni, S., Demares, F., du Rand, E. E., Malod, K., Manrakhan, A., Nicolson, S. W. Tags: RESEARCH ARTICLE Source Type: research

Elevated oxidative stress in pied flycatcher nestlings of eumelanic foster fathers under low rearing temperatures [RESEARCH ARTICLE]
P. E. Teerikorpi, J. Stauffer, P. Ilmonen, S. Calhim, W. Schuett, and T. Laaksonen Striking variation in melanin coloration within natural populations is likely due to the different fitness outcomes of alternative phenotypes in varying environmental conditions. There are two types of melanins. Eumelanins yield blackish hues, while pheomelanins yield reddish hues. The production of eumelanins requires low levels of glutathione (GSH), which is the most important intracellular antioxidant, while the production of pheomelanins requires high levels of GSH. We investigated the oxidative status of male pied flycatchers (Ficedula ...
Source: Journal of Experimental Biology - February 28, 2019 Category: Biology Authors: Teerikorpi, P. E., Stauffer, J., Ilmonen, P., Calhim, S., Schuett, W., Laaksonen, T. Tags: RESEARCH ARTICLE Source Type: research

How buzzing helps bees to pollinate plants [INSIDE JEB]
Kathryn Knight (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - February 27, 2019 Category: Biology Authors: Knight, K. Tags: INSIDE JEB Source Type: research

Threshold effect in the H2O2 production of skeletal muscle mitochondria during fasting and refeeding [RESEARCH ARTICLE]
Damien Roussel, Melanie Boël, Mathieu Mortz, Caroline Romestaing, Claude Duchamp, and Yann Voituron Under nutritional deprivation, the energetic benefits of reducing mitochondrial metabolism are often associated with enhanced harmful pro-oxidant effects and a subsequent long-term negative impact on cellular integrity. However, the flexibility of mitochondrial functioning under stress has rarely been explored during the transition from basal non-phosphorylating to maximal phosphorylating oxygen consumption. Here, we experimentally tested whether ducklings (Cairina moschata), fasted for 6 days and subsequently refed ...
Source: Journal of Experimental Biology - February 27, 2019 Category: Biology Authors: Roussel, D., Boël, M., Mortz, M., Romestaing, C., Duchamp, C., Voituron, Y. Tags: RESEARCH ARTICLE Source Type: research

Energetics and behavior of coral reef fishes during oscillatory swimming in a simulated wave surge [RESEARCH ARTICLE]
Travis M. Marcoux and Keith E. Korsmeyer Oxygen consumption rates were measured for coral reef fishes during swimming in a bidirectional, oscillatory pattern to simulate station-holding in wave-induced, shallow-water flows. For all species examined, increases in wave intensity, as simulated by increases in frequency and amplitude of oscillation, yielded increased metabolic rates and net costs of swimming (NCOS; swimming metabolic rate minus standard metabolic rate). Comparing species with different swimming modes, the caudal fin swimming Kuhlia spp. (Kuhliidae) and simultaneous pectoral–caudal fin swimming Amphiprio...
Source: Journal of Experimental Biology - February 27, 2019 Category: Biology Authors: Marcoux, T. M., Korsmeyer, K. E. Tags: RESEARCH ARTICLE Source Type: research

Lower leg morphology in runners: forefoot strikers have longer heels but not bigger muscles than rearfoot strikers [SHORT COMMUNICATION]
L. S. Wessbecher and A. N. Ahn Foot strike pattern used during running may relate to lower leg morphology. We tested the hypotheses that forefoot strike (FFS) runners have longer plantarflexor moment arms (r) and larger plantarflexor muscles than rearfoot strike (RFS) runners. FFS runners had 17% longer r than RFS runners, but all runners had similarly sized medial and lateral gastrocnemius (MG and LG) muscles. Because muscle size also depends on activation pattern ( Ahn et al., 2011), we compared MG:LG activation bias during walking in 24 runners and 23 sedentary subjects. Half of all subjects activated their MG and LG m...
Source: Journal of Experimental Biology - February 27, 2019 Category: Biology Authors: Wessbecher, L. S., Ahn, A. N. Tags: Comparative biomechanics of movement SHORT COMMUNICATION Source Type: research

Early-life adversity programs long-term cytokine and microglia expression within the HPA axis in female Japanese quail. [RESEARCH ARTICLE]
David J. Walker, Cedric Zimmer, Maria Larriva, Susan D. Healy, and Karen A. Spencer Stress exposure during pre and post-natal development can have persistent and often dysfunctional effects on several physiological systems, including immune function, affecting the ability to combat infection. The neuro-immune response is inextricably linked to the action of the Hypothalamic Pituitary Adrenal (HPA) axis. Cytokines released from neuro-immune cells, including microglia, activate the HPA axis while glucocorticoids in turn regulate cytokine release from microglia. Because of the close links between these two physiological syste...
Source: Journal of Experimental Biology - February 27, 2019 Category: Biology Authors: Walker, D. J., Zimmer, C., Larriva, M., Healy, S. D., Spencer, K. A. Tags: RESEARCH ARTICLE Source Type: research

Moving in complex environments: a biomechanical analysis of locomotion on inclined and narrow substrates [RESEARCH ARTICLE]
Christofer J. Clemente, Taylor J. M. Dick, Rebecca Wheatley, Joshua Gaschk, Ami Fadhillah Amir Abdul Nasir, Skye F. Cameron, and Robbie S. Wilson Characterisation of an organism's performance in different habitats provides insight into the conditions that allow it to survive and reproduce. In recent years, Northern quolls (Dasyurus hallucatus)—a medium-sized semi-arboreal marsupial native to northern Australia—have undergone significant population declines within open forest, woodland and riparian habitats, but less so in rocky areas. To help understand this decline, we quantified the biomechanical performance ...
Source: Journal of Experimental Biology - February 27, 2019 Category: Biology Authors: Clemente, C. J., Dick, T. J. M., Wheatley, R., Gaschk, J., Nasir, A. F. A. A., Cameron, S. F., Wilson, R. S. Tags: RESEARCH ARTICLE Source Type: research

The effects of quality of shelters and prior residence on Marmorkrebs (marbled crayfish) [RESEARCH ARTICLE]
Kazuya Takahashi, Erika Yamaguchi, Naoyuki Fujiyama, and Toshiki Nagayama Many animals fight over a limited valuable resource. In Marmorkrebs (marbled crayfish), large animals usually defeated small opponents but they were frequently beaten by small opponents who were shelter owners. A prior residence effect of marbled crayfish was analyzed quantitatively. More than 2 hr of residency in a shelter was sufficient for small owners to defeat large intruders. Small animals that stayed in a shelter for 24 hr still tended to win following removal of the shelter 10 min before pairing with large intruders, but 2 hr residents were o...
Source: Journal of Experimental Biology - February 27, 2019 Category: Biology Authors: Takahashi, K., Yamaguchi, E., Fujiyama, N., Nagayama, T. Tags: RESEARCH ARTICLE Source Type: research

3D ultrastructural organisation of calcium release units in the avian sarcoplasmic reticulum [RESEARCH ARTICLE]
Thomas M. D. Sheard, Sanjay R. Kharche, Christian Pinali, and Holly A. Shiels Excitation-contraction coupling in vertebrate hearts is underpinned by calcium (Ca2+) release from Ca2+ release units (CRUs). CRUs are formed by clusters of channels called ryanodine receptors on the sarcoplasmic reticulum (SR) within the cardiomyocyte. Distances between CRUs influence the diffusion of Ca2+, thus influencing the rate and strength of excitation-contraction coupling. Avian myocytes lack T-tubules, thus Ca2+ from surface CRUs (peripheral couplings, PCs), must diffuse to internal CRU sites of the corbular SR (cSR) during centripetal ...
Source: Journal of Experimental Biology - February 27, 2019 Category: Biology Authors: Sheard, T. M. D., Kharche, S. R., Pinali, C., Shiels, H. A. Tags: RESEARCH ARTICLE Source Type: research

Mechanical properties of the venomous spines of Pterois volitans and morphology among lionfish species [RESEARCH ARTICLE]
Katherine A. Galloway and Marianne E. Porter The red lionfish, Pterois volitans, an invasive species, has 18 venomous spines: 13 dorsal, 3 anal, and one on each pelvic fin. Fish spines can have several purposes such as defense, intimidation, and for anchoring into crevices. Instead of having hollow spines, lionfish have a tri-lobed cross-sectional shape with grooves that deliver the venom, tapering towards the tip. We aim to quantify the impacts of shape (Second moment of area) and tapering on the mechanical properties of the spine. We performed two-point bending at several positions along the spines of P. volitans to dete...
Source: Journal of Experimental Biology - February 27, 2019 Category: Biology Authors: Galloway, K. A., Porter, M. E. Tags: RESEARCH ARTICLE Source Type: research

Propulsive design principles in a multi-jet siphonophore [RESEARCH ARTICLE]
Kelly R. Sutherland, Brad J. Gemmell, Sean P. Colin, and John H. Costello Coordination of multiple propulsors can provide performance benefits in swimming organisms. Siphonophores are marine colonial organisms that orchestrate the motion of multiple swimming zooids for effective swimming. However, the kinematics at the level of individual swimming zooids (nectophores) have not been examined in detail. We used high speed, high resolution microvideography and particle image velocimetry (PIV) of the physonect siphonophore, Nanomia bijuga, to study the motion of the nectophores and the associated fluid motion during jetting an...
Source: Journal of Experimental Biology - February 27, 2019 Category: Biology Authors: Sutherland, K. R., Gemmell, B. J., Colin, S. P., Costello, J. H. Tags: RESEARCH ARTICLE Source Type: research

Different incubation patterns affect selective antimicrobial properties of the egg interior: experimental evidence from eggs of precocial and altricial birds [RESEARCH ARTICLE]
This study is the first to experimentally demonstrate that different incubation patterns may have selective antimicrobial potentials mediated by species-specific effects on antimicrobial components in the egg white. (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - February 27, 2019 Category: Biology Authors: Svobodova, J., Smidova, L., Gvozdikova Javurkova, V. Tags: RESEARCH ARTICLE Source Type: research

Nathusius' bats optimize long-distance migration by flying at maximum range speed [RESEARCH ARTICLE]
Sara A. Troxell, Marc W. Holderied, Gunars Petersons, and Christian C. Voigt Aerial migration is the fastest, yet most energetically demanding way of seasonal movement between habitats. However, for many taxa, and bats in particular, we lack a clear understanding of the energy requirements for migration. Here, we examined the energetic cost and flight speed of the long-distance migratory Nathusius’ bat (Pipistrellus nathusii). We measured flight metabolism in relation to airspeed in a wind tunnel, inferred the optimal traveling speed over long distances, i.e. maximum range speed, and compared this value with flight ...
Source: Journal of Experimental Biology - February 26, 2019 Category: Biology Authors: Troxell, S. A., Holderied, M. W., Petersons, G., Voigt, C. C. Tags: RESEARCH ARTICLE Source Type: research

Bee and floral traits affect the characteristics of the vibrations experienced by flowers during buzz pollination [RESEARCH ARTICLE]
Blanca Arroyo-Correa, Ceit Beattie, and Mario Vallejo-Marin During buzz pollination, bees use their indirect flight muscles to produce vibrations that are transmitted to the flowers and result in pollen release. Although buzz pollination has been known for>100 years, we are still in the early stages of understanding how bee and floral characteristics affect the production and transmission of floral vibrations. Here, we analysed floral vibrations produced by four closely related bumblebee taxa (Bombus spp.) on two buzz-pollinated plants species (Solanum spp.). We measured floral vibrations transmitted to the flower...
Source: Journal of Experimental Biology - February 25, 2019 Category: Biology Authors: Arroyo-Correa, B., Beattie, C., Vallejo-Marin, M. Tags: RESEARCH ARTICLE Source Type: research

Mechanical properties of the wave-swept kelp Egregia menziesii change with season, growth rate and herbivore wounds [RESEARCH ARTICLE]
Nicholas P. Burnett and M. A. R. Koehl The resistance of macroalgae to damage by hydrodynamic forces depends on the mechanical properties of their tissues. Although factors such as water-flow environment, algal growth rate and damage by herbivores have been shown to influence various material properties of macroalgal tissues, the interplay of these factors as they change seasonally and affect algal mechanical performance has not been worked out. We used the perennial kelp Egregia menziesii to study how the material properties of the rachis supporting a frond changed seasonally over a 2 year period, and how those chan...
Source: Journal of Experimental Biology - February 25, 2019 Category: Biology Authors: Burnett, N. P., Koehl, M. A. R. Tags: RESEARCH ARTICLE Source Type: research

Unexpected eye fat pad likely helps ground squirrels wake up [INSIDE JEB]
Kathryn Knight (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - February 22, 2019 Category: Biology Authors: Knight, K. Tags: INSIDE JEB Source Type: research

Identification of a lipid-rich depot in the orbital cavity of the thirteen-lined ground squirrel [SHORT COMMUNICATION]
Amanda D. V. MacCannell, Kevin J. Sinclair, Glenn J. Tattersall, Charles A. McKenzie, and James F. Staples We discovered a previously undescribed orbital lipid depot in the thirteen-lined ground squirrel during the first ever magnetic resonance image (MRI) of this common experimental model of mammalian hibernation. In animals housed at constant ambient temperatures (5°C or 25°C, 12 h:12 h light:dark photoperiod), the volume of this depot increased in the autumn and decreased in the spring, suggesting an endogenous circannual pattern. Water-fat MRI revealed that throughout the year this depot is composed ...
Source: Journal of Experimental Biology - February 22, 2019 Category: Biology Authors: MacCannell, A. D. V., Sinclair, K. J., Tattersall, G. J., McKenzie, C. A., Staples, J. F. Tags: SHORT COMMUNICATION Source Type: research

Drosophila female fertility and juvenile hormone metabolism depends on the type of Wolbachia infection [RESEARCH ARTICLE]
Nataly E. Gruntenko, Evgenia K. Karpova, Natalya V. Adonyeva, Olga V. Andreenkova, Elena V. Burdina, Yury Yu. Ilinsky, Roman A. Bykov, Petr N. Menshanov, and Inga Yu. Rauschenbach Maternally inherited intracellular bacteria Wolbachia cause both parasitic and mutualistic effects on their numerous insect hosts, including manipulating the host reproductive system in order to increase the bacteria spreading in a host population, and increasing the host fitness. Here, we demonstrate that the type of Wolbachia infection determines the effect on Drosophila melanogaster egg production as a proxy for fecundity, and metabolism of j...
Source: Journal of Experimental Biology - February 22, 2019 Category: Biology Authors: Gruntenko, N. E., Karpova, E. K., Adonyeva, N. V., Andreenkova, O. V., Burdina, E. V., Ilinsky, Y. Y., Bykov, R. A., Menshanov, P. N., Rauschenbach, I. Y. Tags: RESEARCH ARTICLE Source Type: research

Dissecting cause from consequence: a systematic approach to thermal limits [COMMENTARY]
Heath A. MacMillan Thermal limits mark the boundaries of ectotherm performance, and are increasingly appreciated as strong correlates and possible determinants of animal distribution patterns. The mechanisms setting the thermal limits of ectothermic animals are under active study and rigorous debate as we try to reconcile new observations in the lab and field with the knowledge gained from a long history of research on thermal adaptation. Here, I provide a perspective on our divided understanding of the mechanisms setting thermal limits of ectothermic animals. I focus primarily on the fundamental differences between high ...
Source: Journal of Experimental Biology - February 22, 2019 Category: Biology Authors: MacMillan, H. A. Tags: Ecophysiology: responses to environmental stressors and change COMMENTARY Source Type: research

Compliant legs enable lizards to maintain high running speeds on complex terrains [RESEARCH ARTICLE]
Francois Druelle, Jana Goyens, Menelia Vasilopoulou-Kampitsi, and Peter Aerts Substrate variations are likely to compel animal performance in natural environments, as running over complex terrains challenges the dynamic stability of the body differently in each step. Yet, being able to negotiate complex terrains at top speed is a strong advantage for animals that have to deal with predators and evasive prey. Only little is known on how animals negotiate such terrain variability at high speed. We investigated this in fast running Acanthodactylus boskianus lizards, by measuring their 3D kinematics using four synchronized hig...
Source: Journal of Experimental Biology - February 22, 2019 Category: Biology Authors: Druelle, F., Goyens, J., Vasilopoulou-Kampitsi, M., Aerts, P. Tags: RESEARCH ARTICLE Source Type: research

Antioxidant response to acute cold exposure and during recovery in juvenile Chinese soft-shelled turtles (Pelodiscus sinensis) [RESEARCH ARTICLE]
Bo-Jian Chen, Wen-Yi Zhang, Cui-Juan Niu, Wen-Jie Li, Hui Jia, and Kenneth B. Storey The antioxidant defense protects turtles from oxidative stress caused by adverse environment conditions, such as acute thermal fluctuations. However, it remains unclear how these defenses work. The present study examined changes in key enzymes of the enzymatic antioxidant system and the glutathione (GSH) system at both the mRNA and enzyme activity levels during acute cold exposure and recovery in juvenile Chinese soft-shelled turtles, Pelodiscus sinensis. Transcript levels of the upstream regulator NF-E2-related factor 2 (Nrf2) were also ...
Source: Journal of Experimental Biology - February 21, 2019 Category: Biology Authors: Chen, B.-J., Zhang, W.-Y., Niu, C.-J., Li, W.-J., Jia, H., Storey, K. B. Tags: RESEARCH ARTICLE Source Type: research

Metabolic fuel use after feeding in the zebrafish (Danio rerio): a respirometric analysis [SHORT COMMUNICATION]
Marcio S. Ferreira, Chris M. Wood, Till S. Harter, Giorgi Dal Pont, Adalberto L. Val, and Philip G. D. Matthews We used respirometric theory and a new respirometry apparatus to assess, for the first time, the sequential oxidation of the major metabolic fuels during the post-prandial period (10 h) in adult zebrafish fed with commercial pellets (51% protein, 2.12% ration). Compared with a fasted group, fed fish presented peak increases of oxygen consumption (78%), and carbon dioxide (80%) and nitrogen excretion rates (338%) at 7–8 h, and rates remained elevated at 10 h. The respiratory quotient increase...
Source: Journal of Experimental Biology - February 21, 2019 Category: Biology Authors: Ferreira, M. S., Wood, C. M., Harter, T. S., Dal Pont, G., Val, A. L., Matthews, P. G. D. Tags: SHORT COMMUNICATION Source Type: research

Brief exposure to intense turbulence induces a sustained life-history shift in echinoids [RESEARCH ARTICLE]
Matthew C. Ferner, Jason Hodin, Gabriel Ng, and Brian Gaylord In coastal ecosystems, attributes of fluid motion can prompt animal larvae to rise or sink in the water column and to select microhabitats within which they attach and commit to a benthic existence. In echinoid (sea urchin and sand dollar) larvae living along wave-exposed shorelines, intense turbulence characteristic of surf zones can cause individuals to undergo an abrupt life-history shift characterized by precocious entry into competence – the stage at which larvae will settle and complete metamorphosis in response to local cues. However, the mechanist...
Source: Journal of Experimental Biology - February 21, 2019 Category: Biology Authors: Ferner, M. C., Hodin, J., Ng, G., Gaylord, B. Tags: RESEARCH ARTICLE Source Type: research

Pecking not so bird-brained after all [INSIDE JEB]
Kathryn Knight (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - February 20, 2019 Category: Biology Authors: Knight, K. Tags: INSIDE JEB Source Type: research

Bark beetles use a spring-loaded mechanism to produce variable song patterns [SHORT COMMUNICATION]
Amanda A. Lindeman and Jayne E. Yack Many insects vary their song patterns to communicate different messages, but the underlying biomechanisms are often poorly understood. Here, we report on the mechanics of sound production and variation in an elytro-tergal stridulator, male Dendroctonus valens bark beetles. Using ablation experiments coupled with high-speed video and audio recordings, we show that: (1) chirps are produced using a stridulatory file on the left elytron (forewing) and a protrusion (plectrum) on the seventh abdominal segment; (2) chirps are produced by ‘spring stridulation’, a catch-and-release ...
Source: Journal of Experimental Biology - February 20, 2019 Category: Biology Authors: Lindeman, A. A., Yack, J. E. Tags: SHORT COMMUNICATION Source Type: research

Rapid adjustment of pecking trajectory to prism-induced visual shifts in crows as compared with pigeons [RESEARCH ARTICLE]
Hiroshi Matsui and Ei-Ichi Izawa Pecking in birds is analogous to reaching and grasping movements in primates. Earlier studies on visuomotor control in birds, which were conducted mostly in pigeons, suggested that avian pecking is controlled feedforwardly, and is out of the control of visual guidance during movement. However, recent studies using crows suggested a role of vision in pecking control during movement. To unveil what visuomotor mechanisms underlie the flexibility of pecking in crows, we examined whether pigeons and crows adjust their pecking to the visual distortion induced by prisms. Because prisms induce vis...
Source: Journal of Experimental Biology - February 20, 2019 Category: Biology Authors: Matsui, H., Izawa, E.-I. Tags: RESEARCH ARTICLE Source Type: research

Contraction of atrial smooth muscle reduces cardiac output in perfused turtle hearts [RESEARCH ARTICLE]
William Joyce, Michael Axelsson, and Tobias Wang Unusual undulations in resting tension (tonus waves) were described in isolated atria from freshwater turtle more than a century ago. These tonus waves were soon after married with the histological demonstration of a rich layer of smooth muscle on the luminal side of the atrial wall. Research thereafter waned and the functional significance of this smooth muscle has remained obscure. Here we provide evidence that contraction of the smooth muscle in the atria may be able to change cardiac output in turtle hearts. In in situ perfused hearts of the red-eared slider turtle (Trac...
Source: Journal of Experimental Biology - February 20, 2019 Category: Biology Authors: Joyce, W., Axelsson, M., Wang, T. Tags: RESEARCH ARTICLE Source Type: research

Variable vision in variable environments: the visual system of an invasive cichlid (Cichla monoculus, Agassiz, 1831) in Lake Gatun, Panama [RESEARCH ARTICLE]
Daniel Escobar-Camacho, Michele E. R. Pierotti, Victoria Ferenc, Diana M. T Sharpe, Erica Ramos, Cesar Martins, and Karen L. Carleton An adaptive visual system is essential for organisms inhabiting new or changing light environments. The Panama Canal exhibits such variable environments due to its anthropogenic origin and current human activities. Within the Panama Canal, Lake Gatun harbours several exotic fish species including the invasive peacock bass (Cichla monoculus, Agassiz, 1831), a predatory Amazonian cichlid. In this research, through spectral measurements and molecular and physiological experiments, we studied th...
Source: Journal of Experimental Biology - February 20, 2019 Category: Biology Authors: Escobar-Camacho, D., Pierotti, M. E. R., Ferenc, V., Sharpe, D. M. T., Ramos, E., Martins, C., Carleton, K. L. Tags: RESEARCH ARTICLE Source Type: research

The implications of time on the ground on running economy: less is not always better [RESEARCH ARTICLE]
Thibault Lussiana, Aurelien Patoz, Cyrille Gindre, Laurent Mourot, and Kim Hebert-Losier A lower duty factor (DF) reflects a greater relative contribution of leg swing to ground contact time during the running step. Increasing time on the ground has been reported in the scientific literature to both increase and decrease the energy cost (EC) of running, with DF reported to be highly variable in runners. As increasing running speed aligns running kinematics more closely with spring-mass model behaviors and re-use of elastic energy, we compared the centre of mass (COM) displacement and EC between runners with a low (DFlow) a...
Source: Journal of Experimental Biology - February 20, 2019 Category: Biology Authors: Lussiana, T., Patoz, A., Gindre, C., Mourot, L., Hebert-Losier, K. Tags: RESEARCH ARTICLE Source Type: research

Energetics of migratory bats during stopover: a test of the torpor-assisted migration hypothesis [RESEARCH ARTICLE]
This study provides support for the torpor-assisted migration hypothesis, and furthers our understanding of the energy budgets of migratory bats. (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - February 20, 2019 Category: Biology Authors: Baloun, D. E., Guglielmo, C. G. Tags: RESEARCH ARTICLE Source Type: research

Does the left aorta provide proton-rich blood to the gut when crocodilians digest a meal? [SHORT COMMUNICATION]
Justin L. Conner, Janna L. Crossley, Ruth Elsey, Derek Nelson, Tobias Wang, and Dane A. Crossley II Reptiles have the capacity to differentially perfuse the systemic and pulmonary vascular circuits via autonomic regulation of the heart and the vascular trees. While this aptitude is widely recognized, the role of "shunting" as a homeostatic mechanism to match convective transport with tissue demand remains unknown. In crocodilians, it has been hypothesized that a pulmonary vascular bypass of systemic venous blood, a right-to-left shunt (R-L), serves to deliver CO2-rich blood with protons needed for gastric acid se...
Source: Journal of Experimental Biology - February 20, 2019 Category: Biology Authors: Conner, J. L., Crossley, J. L., Elsey, R., Nelson, D., Wang, T., Crossley, D. A. Tags: SHORT COMMUNICATION Source Type: research

Speed control and force-vectoring of bluebottle flies in a magnetically levitated flight mill [RESEARCH ARTICLE]
Shih-Jung Hsu, Neel Thakur, and Bo Cheng Flies fly at a broad range of speeds and produce sophisticated aerial maneuvers with precisely controlled wing movements. Remarkably, only subtle changes in wing motion are used by flies to produce aerial maneuvers, resulting in little directional tilt of the aerodynamic force vector relative to the body. Therefore, it is often considered that flies fly according to a helicopter model and control speed mainly via force vectoring by body pitch change. Here, we examined the speed control of bluebottle flies using a magnetically levitated (MAGLEV) flight mill, as they fly at different...
Source: Journal of Experimental Biology - February 19, 2019 Category: Biology Authors: Hsu, S.-J., Thakur, N., Cheng, B. Tags: Comparative biomechanics of movement RESEARCH ARTICLE Source Type: research

Hunting great white sharks could motor but prefer to mosey [INSIDE JEB]
Kathryn Knight (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - February 18, 2019 Category: Biology Authors: Knight, K. Tags: INSIDE JEB Source Type: research