The need for speed: functional specializations of locomotor and feeding muscles in Anolis lizards [RESEARCH ARTICLE]
Christopher V. Anderson and Thomas J. Roberts Muscles often perform diverse mechanical roles within an organism. Tuning of contractile properties may therefore provide an opportunity for muscles to better perform their different roles and impact their associated whole-organism performance. Here, we examined the muscle contractile physiology of a jaw and a leg muscle in five Anolis species to determine whether consistent physiological differences are found in these muscles. We found that these jaw and leg muscles exhibited consistent patterns of variation across species, which may be related to the functional use of each m...
Source: Journal of Experimental Biology - January 27, 2020 Category: Biology Authors: Anderson, C. V., Roberts, T. J. Tags: Comparative biomechanics of movement RESEARCH ARTICLE Source Type: research

Metabolic partitioning of sucrose and seasonal changes in fat turnover rate in ruby-throated hummingbirds (Archilochus colubris) [RESEARCH ARTICLE]
Morag F. Dick, Antonio Alcantara-Tangonan, Yazan Shamli Oghli, and Kenneth C. Welch Hummingbirds fuel their high energy needs with the fructose and glucose in their nectar diets. These sugars are used both to fuel immediate energy needs and to build fat stores to fuel future fasting periods. Fasting hummingbirds can deplete energy stores in only hours and need to be continuously replacing these stores while feeding and foraging. Whether and how hummingbirds partition dietary fructose and glucose towards immediate oxidation versus fat storage is unknown. Using a chronic stable isotope tracer methodology, we examined whethe...
Source: Journal of Experimental Biology - January 27, 2020 Category: Biology Authors: Dick, M. F., Alcantara-Tangonan, A., Oghli, Y. S., Welch, K. C. Tags: RESEARCH ARTICLE Source Type: research

Evidence for a rapid cold hardening response in cultured Drosophila S2 cells [SHORT COMMUNICATION]
Emily A. W. Nadeau and Nicholas M. Teets The ability to quickly respond to changes in environmental temperature is critical for organisms living in thermally variable environments. To cope with sudden drops in temperature, insects and other ectotherms are capable of rapid cold hardening (RCH), in which mild chilling significantly enhances cold tolerance within minutes. While the ecological significance of RCH is well established, the mechanisms underlying RCH are still poorly understood. Previous work has demonstrated that RCH is regulated at the cellular level by post-translational signaling mechanisms, and here we teste...
Source: Journal of Experimental Biology - January 27, 2020 Category: Biology Authors: Nadeau, E. A. W., Teets, N. M. Tags: SHORT COMMUNICATION Source Type: research

Variation in limb loading magnitude and timing in tetrapods [RESEARCH ARTICLE]
Michael C. Granatosky, Eric J. McElroy, Pierre Lemelin, Stephen M. Reilly, John A. Nyakatura, Emanuel Andrada, Brandon M. Kilbourne, Vivian R. Allen, Michael T. Butcher, Richard W. Blob, and Callum F. Ross Comparative analyses of locomotion in tetrapods reveal two patterns of stride cycle variability. Tachymetabolic tetrapods (birds and mammals) have lower inter-cycle variation in stride duration than bradymetabolic tetrapods (amphibians, lizards, turtles and crocodilians). This pattern has been linked to the fact that birds and mammals share enlarged cerebella, relatively enlarged and heavily myelinated Ia afferents, and...
Source: Journal of Experimental Biology - January 27, 2020 Category: Biology Authors: Granatosky, M. C., McElroy, E. J., Lemelin, P., Reilly, S. M., Nyakatura, J. A., Andrada, E., Kilbourne, B. M., Allen, V. R., Butcher, M. T., Blob, R. W., Ross, C. F. Tags: Comparative biomechanics of movement RESEARCH ARTICLE Source Type: research

Effects of a titin mutation on force enhancement and force depression in mouse soleus muscles [RESEARCH ARTICLE]
Uzma Tahir, Jenna A. Monroy, Nicole A. Rice, and Kiisa C. Nishikawa The active isometric force produced by muscles varies with muscle length in accordance with the force–length relationship. Compared with isometric contractions at the same final length, force increases after active lengthening (force enhancement) and decreases after active shortening (force depression). In addition to cross-bridges, titin has been suggested to contribute to force enhancement and depression. Although titin is too compliant in passive muscles to contribute to active tension at short sarcomere lengths on the ascending limb and plateau ...
Source: Journal of Experimental Biology - January 27, 2020 Category: Biology Authors: Tahir, U., Monroy, J. A., Rice, N. A., Nishikawa, K. C. Tags: Comparative biomechanics of movement RESEARCH ARTICLE Source Type: research

Mind the gap: natural cleft palates reduce biting performance in bats [RESEARCH ARTICLE]
Abigail A. Curtis, Jessica H. Arbour, and Sharlene E. Santana Novel morphological traits pose interesting evolutionary paradoxes when they become widespread in a lineage while being deleterious in others. Cleft palate is a rare congenital condition in mammals in which the incisor-bearing premaxilla bones of the upper jaw develop abnormally. However, ~50% of bat species have natural, non-pathological cleft palates. We used the family Vespertilionidae as a model and linear and geometric morphometrics within a phylogenetic framework to (1) explore evolutionary patterns in cleft morphology, and (2) test whether cleft morpholo...
Source: Journal of Experimental Biology - January 27, 2020 Category: Biology Authors: Curtis, A. A., Arbour, J. H., Santana, S. E. Tags: RESEARCH ARTICLE Source Type: research

The shape-effect of flagella is more important than bottom-heaviness on passive gravitactic orientation in Chlamydomonas reinhardtii [RESEARCH ARTICLE]
Azusa Kage, Toshihiro Omori, Kenji Kikuchi, and Takuji Ishikawa The way the unicellular, biflagellated, green alga Chlamydomonas orients upward has long been discussed in terms of both mechanics and physiology. In this paper we focus on the mechanics, i.e. the "passive" mechanisms, of gravitaxis. To rotate the body upwards, cellular asymmetry is critical. Chlamydomonas can be depicted as a nearly spherical cell body with two anterior, symmetric flagella. This paper looks at the question of whether the existence of the flagella significantly affects torque generation in upward reorientation. The "Density asym...
Source: Journal of Experimental Biology - January 27, 2020 Category: Biology Authors: Kage, A., Omori, T., Kikuchi, K., Ishikawa, T. Tags: RESEARCH ARTICLE Source Type: research

Medium compensation in a spring-actuated system [SHORT COMMUNICATION]
Kathryn D. Feller, Gregory P. Sutton, and Paloma T. Gonzalez-Bellido Mantis shrimp strikes are one of the fastest animal movements, despite their occurrence in a water medium with viscous drag. Since the strike is produced by a latch-mediated spring-actuated system and not directly driven by muscle action, we predicted that strikes performed in air would be faster than underwater due to reduction in the medium's drag. Using high-speed video analysis of stereotyped strikes elicited from Squilla mantis, we found the exact opposite: strikes are much slower and less powerful in air than in water. S. mantis strikes in air have ...
Source: Journal of Experimental Biology - January 27, 2020 Category: Biology Authors: Feller, K. D., Sutton, G. P., Gonzalez-Bellido, P. T. Tags: SHORT COMMUNICATION Source Type: research

Interspecific variation in hypoxia tolerance and hypoxia acclimation responses in killifish from the family Fundulidae [RESEARCH ARTICLE]
We examined the effects of chronic (28 d) exposure to constant hypoxia (2 kPa) or nocturnal intermittent hypoxia (12 h normoxia: 12 h hypoxia) in a subset of species. Some species exhibited a two-breakpoint model in MO2 caused by early, modest declines in MO2 in moderate hypoxia. We found that hypoxia tolerance varied appreciably across species: F. confluentus was the most tolerant (lowest PLOE and Pcrit, longest tLOE), whereas F. rathbuni and F. diaphanus were the least tolerant. However, there was not a consistent pattern of interspecific variation for different indices of hypoxia tolerance, with or without taking phylog...
Source: Journal of Experimental Biology - January 27, 2020 Category: Biology Authors: Borowiec, B. G., Hoffman, R. D., Hess, C. D., Galvez, F., Scott, G. R. Tags: RESEARCH ARTICLE Source Type: research

Corticotropin-releasing factor protects against ammonia neurotoxicity in isolated larval zebrafish brains [RESEARCH ARTICLE]
Tegan A. Williams and Nicholas J. Bernier The physiological roles of corticotropin-releasing factor (CRF) have recently been extended to cytoprotection. Here, to determine whether CRF is neuroprotective in fish, the effects of CRF against high environmental ammonia (HEA)-mediated neurogenic impairment and cell death were investigated in zebrafish. In vivo, exposure of 1 day post-fertilization (dpf) embryos to HEA only reduced the expression of the determined neuron marker, neurod1. In contrast, in 5 dpf larvae, HEA increased the expression of nes and sox2, neural progenitor cell markers, and reduced the expression of neuro...
Source: Journal of Experimental Biology - January 27, 2020 Category: Biology Authors: Williams, T. A., Bernier, N. J. Tags: RESEARCH ARTICLE Source Type: research

The impact of a high-fat diet in mice is dependent on duration and age, and differs between muscles [RESEARCH ARTICLE]
G. A. M. Messa, M. Piasecki, J. Hurst, C. Hill, J. Tallis, and H. Degens Prolonged high-fat diets (HFD) can cause intramyocellular lipids (IMCL) accumulation that may negatively affect muscle function. We investigated the duration of a HFD required to instigate these changes, and whether effects are muscle-specific and aggravated in older age. Muscle morphology was determined in the soleus, extensor digitorum longus (EDL) and diaphragm muscles from female CD-1 mice divided into 5 groups: young fed a HFD for 8 weeks (YS-HFD, n=16), young fed a HFD for 16 weeks (YL-HFD, n=28) and young control (Y-CON, n=28). The young animal...
Source: Journal of Experimental Biology - January 27, 2020 Category: Biology Authors: Messa, G. A. M., Piasecki, M., Hurst, J., Hill, C., Tallis, J., Degens, H. Tags: RESEARCH ARTICLE Source Type: research

A salamander that chews using complex, three-dimensional mandible movements [RESEARCH ARTICLE]
Daniel Schwarz, Nicolai Konow, Yonas Tolosa Roba, and Egon Heiss It is generally accepted that most non-mammal tetrapods have a hinge-like jaw operation restricted to vertical opening and closing movements. Many mammal jaw joints, by contrast, operate in more complex, three-dimensional ways, involving not only vertical, but also propalinal (rostro-caudal) and transverse (lateral) movements. Data on intraoral food processing in lissamphibians and sauropsids has prompted a generally accepted view that these groups mostly swallow food unreduced, and that in those cases where lissamphibians and sauropsids chew, they mostly use...
Source: Journal of Experimental Biology - January 27, 2020 Category: Biology Authors: Schwarz, D., Konow, N., Roba, Y. T., Heiss, E. Tags: RESEARCH ARTICLE Source Type: research

Oxygenation properties of hemoglobin and the evolutionary origins of isoform multiplicity in an amphibious air-breathing fish, the blue-spotted mudskipper (Boleophthalmus pectinirostris) [RESEARCH ARTICLE]
Jay F. Storz, Chandrasekhar Natarajan, Magnus K. Grouleff, Michael Vandewege, Federico G. Hoffmann, Xinxin You, Byrappa Venkatesh, and Angela Fago Among the numerous lineages of teleost fish that have independently transitioned from obligate water breathing to facultative air breathing, evolved properties of hemoglobin (Hb)–O2 transport may have been shaped by the prevalence and severity of aquatic hypoxia (which influences the extent to which fish are compelled to switch to aerial respiration) as well as the anatomical design of air-breathing structures and the cardiovascular system. Here, we examined the structure...
Source: Journal of Experimental Biology - January 23, 2020 Category: Biology Authors: Storz, J. F., Natarajan, C., Grouleff, M. K., Vandewege, M., Hoffmann, F. G., You, X., Venkatesh, B., Fago, A. Tags: RESEARCH ARTICLE Source Type: research

Sexual dimorphism in human arm power and force: implications for sexual selection on fighting ability [RESEARCH ARTICLE]
Jeremy S. Morris, Jenna Link, James C. Martin, and David R. Carrier Sexual dimorphism often arises from selection on specific musculoskeletal traits that improve male fighting performance. In humans, one common form of fighting includes using the fists as weapons. Here, we tested the hypothesis that selection on male fighting performance has led to the evolution of sexual dimorphism in the musculoskeletal system that powers striking with a fist. We compared male and female arm cranking power output, using it as a proxy for the power production component of striking with a fist. Using backward arm cranking as an unselected...
Source: Journal of Experimental Biology - January 23, 2020 Category: Biology Authors: Morris, J. S., Link, J., Martin, J. C., Carrier, D. R. Tags: Comparative biomechanics of movement RESEARCH ARTICLE Source Type: research

Pectoral fin kinematics and motor patterns are shaped by fin ray mechanosensation during steady swimming in Scarus quoyi [RESEARCH ARTICLE]
Brett R. Aiello, Aaron M. Olsen, Chris E. Mathis, Mark W. Westneat, and Melina E. Hale For many fish species, rhythmic movement of the pectoral fins, or forelimbs, drives locomotion. In terrestrial vertebrates, normal limb-based rhythmic gaits require ongoing modulation with limb mechanosensors. Given the complexity of the fluid environment and dexterity of fish swimming through it, we hypothesize that mechanosensory modulation is also critical to normal fin-based swimming. Here, we examined the role of sensory feedback from the pectoral fin rays and membrane on the neuromuscular control and kinematics of pectoral fin-bas...
Source: Journal of Experimental Biology - January 23, 2020 Category: Biology Authors: Aiello, B. R., Olsen, A. M., Mathis, C. E., Westneat, M. W., Hale, M. E. Tags: Comparative biomechanics of movement RESEARCH ARTICLE Source Type: research

Evidence that stress-induced changes in surface temperature serve a thermoregulatory function [RESEARCH ARTICLE]
Joshua K. Robertson, Gabriela Mastromonaco, and Gary Burness Changes in body temperature following exposure to stressors have been documented for nearly two millennia, however, the functional value of this phenomenon is poorly understood. We tested two competing hypotheses to explain stress-induced changes in temperature, with respect to surface tissues. Under the first hypothesis, changes in surface temperature are a consequence of vasoconstriction that occurs to attenuate blood-loss in the event of injury and serves no functional purpose per se; defined as the Haemoprotective Hypothesis. Under the second hypothesis, chan...
Source: Journal of Experimental Biology - January 23, 2020 Category: Biology Authors: Robertson, J. K., Mastromonaco, G., Burness, G. Tags: RESEARCH ARTICLE Source Type: research

Experimental manipulation of perceived predation risk and cortisol generate contrasting trait trajectories in plastic crucian carp [RESEARCH ARTICLE]
Jerker Vinterstare, Kaj Hulthen, P. Anders Nilsson, Helen Nilsson Sköld, and Christer Brönmark Most animals constitute potential prey and must respond appropriately to predator-mediated stress in order to survive. Numerous prey also adaptively tailor their response to the prevailing level of risk and stress imposed by their natural enemies, i.e. they adopt an inducible defence strategy. Predator exposure may activate the stress axis, and drive the expression of anti-predator traits that facilitate survival in a high-risk environment (the predation-stress-hypothesis). Here, we quantified two key morphological anti-preda...
Source: Journal of Experimental Biology - January 23, 2020 Category: Biology Authors: Vinterstare, J., Hulthen, K., Nilsson, P. A., Nilsson Sköld, H., Brönmark, C. Tags: RESEARCH ARTICLE Source Type: research

Measurement of mitochondrial respiration in permeabilized fish gills [METHODS [amp ] TECHNIQUES]
Neal J. Dawson, Caroline Millet, Colin Selman, and Neil B. Metcalfe Physiological investigations of fish gills have traditionally been centered on the two principal functions of the gills, gas exchange and ion regulation. Mitochondrion-rich cells (MRCs) are primarily found within the gill filaments of fish, and are thought to proliferate in order to increase the ionoregulatory capacity of the gill in response to environmentally-induced osmotic challenges. However, surprisingly little attention has been paid to the metabolic function of mitochondria within fish gills. Here we describe and validate a simple protocol for the ...
Source: Journal of Experimental Biology - January 23, 2020 Category: Biology Authors: Dawson, N. J., Millet, C., Selman, C., Metcalfe, N. B. Tags: METHODS [amp ] TECHNIQUES Source Type: research

Bioluminescence induction in the ophiuroid Amphiura filiformis (Echinodermata) [SHORT COMMUNICATION]
Jerome Mallefet, Laurent Duchatelet, and Constance Coubris Bioluminescence is a widespread phenomenon in the marine environment. Among luminous substrates, coelenterazine is the most widespread luciferin, found in more than nine phyla. The wide phylogenetic coverage of this light-emitting molecule has led to the hypothesis of its dietary acquisition that was demonstrated in one cnidarian and one lophogastrid shrimp species so far. Within Ophiuroidea, the dominant class of luminous echinoderms, Amphiura filiformis is a model species known to use coelenterazine as substrate of a luciferin / luciferase luminous system.The aim...
Source: Journal of Experimental Biology - January 23, 2020 Category: Biology Authors: Mallefet, J., Duchatelet, L., Coubris, C. Tags: SHORT COMMUNICATION Source Type: research

Rorqual whale nasal plugs: protecting the respiratory tract against water entry and barotrauma [RESEARCH ARTICLE]
Kelsey N. Gil, Margo A. Lillie, A. Wayne Vogl, and Robert E. Shadwick The upper respiratory tract of rorquals, lunge-feeding baleen whales, must be protected against water incursion and against the risk of barotrauma at depth, where air-filled spaces like the bony nasal cavities may experience high adverse pressure gradients. We hypothesize these two disparate tasks are accomplished by paired cylindrical nasal plugs that attach on the rostrum and deep inside the nasal cavity. Here we present evidence that the large size and deep attachment of the plugs is a compromise allowing them to block the nasal cavities to prevent wa...
Source: Journal of Experimental Biology - January 23, 2020 Category: Biology Authors: Gil, K. N., Lillie, M. A., Vogl, A. W., Shadwick, R. E. Tags: RESEARCH ARTICLE Source Type: research

The visual spectral sensitivity of the Chilean recluse spider Loxosceles laeta [RESEARCH ARTICLE]
In this study, we analyzed the visual spectral sensitivity of the Chilean recluse spider Loxosceles laeta, a synanthropic species posing a significant threat to humans, using electroretinogram recordings of its three eye types and open field tests with localized chromatic illumination for behavioral analysis. The electroretinogram displayed two sensitivity peaks in the ultraviolet and green ranges, and no differences were observed between the three eye types and between male and female specimens. Selective chromatic adaptation reduced overall light sensitivity, but did not support the expression of more than one type of rh...
Source: Journal of Experimental Biology - January 22, 2020 Category: Biology Authors: Tapia, F., Olivares, J., Schmachtenberg, O. Tags: RESEARCH ARTICLE Source Type: research

Reassessing the contribution of the Na+/H+ exchanger Nhe3b to Na+ uptake in zebrafish (Danio rerio) using CRISPR/Cas9 gene editing [RESEARCH ARTICLE]
Alex M. Zimmer, Khatereh Shir-Mohammadi, Raymond W. M. Kwong, and Steve F. Perry Freshwater fishes absorb Na+ from their dilute environment using ion-transporting cells. In larval zebrafish (Danio rerio), Na+ uptake is coordinated by (1) Na+/H+ exchanger 3b (Nhe3b) and (2) H+-ATPase-powered electrogenic uptake in H+-ATPase-rich (HR) cells and by (3) Na+-Cl–-cotransporter (Ncc) expressed in NCC cells. The present study aimed to better understand the roles of these three proteins in Na+ uptake by larval zebrafish under ‘normal’ (800 µmol l–1) and ‘low’ (10 µmol&...
Source: Journal of Experimental Biology - January 22, 2020 Category: Biology Authors: Zimmer, A. M., Shir-Mohammadi, K., Kwong, R. W. M., Perry, S. F. Tags: RESEARCH ARTICLE Source Type: research

Frogs seek hypoxic microhabitats that accentuate metabolic depression during dormancy [RESEARCH ARTICLE]
Giulia S. Rossi, Rebecca L. Cramp, Patricia A. Wright, and Craig E. Franklin Many animals occupy microhabitats during dormancy where they may encounter hypoxic conditions (e.g. subterranean burrows). We used the green-striped burrowing frog (Cyclorana alboguttata) to test the hypothesis that animals seek hypoxic microhabitats that accentuate metabolic depression during dormancy. We first measured the partial pressure of oxygen (PO2) within artificial cavities excavated in wet clay soil, which simulated C. alboguttata underground aestivation chambers, and recorded hypoxic conditions (PO2 as low as 8.9 kPa). Using...
Source: Journal of Experimental Biology - January 21, 2020 Category: Biology Authors: Rossi, G. S., Cramp, R. L., Wright, P. A., Franklin, C. E. Tags: RESEARCH ARTICLE Source Type: research

Hypoxia-seeking behavior, metabolic depression and skeletal muscle function in an amphibious fish out of water [RESEARCH ARTICLE]
Giulia S. Rossi and Patricia A. Wright Several animals enter a state of dormancy to survive harsh environmental conditions. During dormancy, metabolic depression can be critical for economizing on limited endogenous energy reserves. We used two isogenic strains (strain 1 and strain 2) of a self-fertilizing amphibious fish (Kryptolebias marmoratus) to test the hypothesis that animals seek hypoxic microhabitats that, in turn, accentuate metabolic depression during dormancy. Using custom-built tunnels that maintained a longitudinal O2 gradient (hypoxic to normoxic), we assessed the O2 preference of K. marmoratus during prolo...
Source: Journal of Experimental Biology - January 21, 2020 Category: Biology Authors: Rossi, G. S., Wright, P. A. Tags: RESEARCH ARTICLE Source Type: research

Investigating the relationship between corticosterone and glucose in a reptile [RESEARCH ARTICLE]
This study highlights the need for testing mechanisms in wild organisms by combining in situ observations with manipulative studies. (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - January 21, 2020 Category: Biology Authors: Neuman-Lee, L. A., Hudson, S. B., Webb, A. C., French, S. S. Tags: RESEARCH ARTICLE Source Type: research

A cerebellum-like circuit in the lateral line system of fish cancels mechanosensory input associated with its own movements [RESEARCH ARTICLE]
Krista E. Perks, Anna Krotinger, and David Bodznick An animal's own movement exerts a profound impact on sensory input to its nervous system. Peripheral sensory receptors do not distinguish externally generated stimuli from stimuli generated by an animal's own behavior (reafference) -- though the animal often must. One way that nervous systems can solve this problem is to provide movement-related signals (copies of motor commands and sensory feedback) to sensory systems, which can then be used to generate predictions that oppose or cancel out sensory responses to reafference. Here, we study the use of movement-related sign...
Source: Journal of Experimental Biology - January 17, 2020 Category: Biology Authors: Perks, K. E., Krotinger, A., Bodznick, D. Tags: RESEARCH ARTICLE Source Type: research

Salt-water acclimation of the estuarine crocodile Crocodylus porosus involves enhanced ion transport properties of the urodaeum and rectum [RESEARCH ARTICLE]
M. Grosell, R. M. Heuer, N. C. Wu, R. L. Cramp, Y. Wang, E. M. Mager, R. G. Dwyer, and C. E. Franklin Estuarine crocodiles Crocodylus porosus inhabit freshwater, estuarine and marine environments. Despite being known to undertake extensive movements throughout and between hypo- and hyperosmotic environments, little is known on the role of the cloaca in coping with changes in salinity. In addition to the well-documented functional plasticity of the lingual salt glands, we report here that the middle of the three cloacal segments (i.e. the urodaeum), responds to increased ambient salinity to enhance solute-coupled water abso...
Source: Journal of Experimental Biology - January 17, 2020 Category: Biology Authors: Grosell, M., Heuer, R. M., Wu, N. C., Cramp, R. L., Wang, Y., Mager, E. M., Dwyer, R. G., Franklin, C. E. Tags: RESEARCH ARTICLE Source Type: research

Acoustic behaviour of male European lobsters (Homarus gammarus) during agonistic encounters [RESEARCH ARTICLE]
In this study, we show that they also produce buzzing sounds during these encounters. This result was missed in earlier studies because low frequency buzzing sounds are highly attenuated in tanks, and are thus difficult to detect with hydrophones. To address this issue, we designed a behavioural tank experiment with hydrophones, and accelerometers placed on the lobsters to directly detect their carapace vibrations (i.e. the sources of the buzzing sounds). While we found that both dominant and submissive individuals produced carapace vibrations during every agonistic encounter, very few of the associated buzzing sounds (15 ...
Source: Journal of Experimental Biology - January 17, 2020 Category: Biology Authors: Jezequel, Y., Coston-Guarini, J., Chauvaud, L., Bonnel, J. Tags: RESEARCH ARTICLE Source Type: research

Induction of vitellogenesis, MF synthesis and ecdysteroidogenesis in two edible crabs by arachidonic acid and prostaglandins [RESEARCH ARTICLE]
C. H. Swetha, B. P. Girish, M. Hemalatha, and P. Sreenivasula Reddy The present study investigated the effect of arachidonic acid (AA) and selected prostaglandins on the regulation of vitellogenesis, ecdysteroidogenesis and methyl farnesoate synthesis in the fresh water crab, Oziotelphusa senex senex and the giant mud crab, Scylla serrata. Administration of AA and prostaglandin F2α (PGF2α) and prostaglandin E2 (PGE2) significantly increased ovarian index, oocyte diameter and ovarian vitellogenin levels and ecdysteroid and methyl farnesoate levels in the hemolymph of crabs. Secretions of methyl farnesoate (MF) a...
Source: Journal of Experimental Biology - January 17, 2020 Category: Biology Authors: Swetha, C. H., Girish, B. P., Hemalatha, M., Reddy, P. S. Tags: RESEARCH ARTICLE Source Type: research

Maintenance of hindgut reabsorption during cold exposure is a key adaptation for Drosophila cold tolerance [RESEARCH ARTICLE]
Mads Kuhlmann Andersen and Johannes Overgaard Maintaining extracellular osmotic and ionic homeostasis is crucial for organismal function. In insects, hemolymph volume and ion content is regulated by the secretory Malpighian tubules and reabsorptive hindgut. When exposed to stressful cold, homeostasis is gradually disrupted, characterized by a debilitating increase in extracellular K+ concentration (hyperkalemia). Accordingly, studies have found a strong link between the species-specific cold tolerance and their ability to maintain ion and water homeostasis at low temperature. This is also true for drosophilids where inter-...
Source: Journal of Experimental Biology - January 17, 2020 Category: Biology Authors: Andersen, M. K., Overgaard, J. Tags: RESEARCH ARTICLE Source Type: research

Short-term dehydration influences baseline, but not stress-induced corticosterone levels in the House sparrow (Passer domesticus) [RESEARCH ARTICLE]
In this study, we experimentally imposed a temporary water shortage (~20 hours) to captive House sparrows in order to investigate the consequences of short-term dehydration on baseline and stress-induced corticosterone levels. As expected, water-deprived birds displayed higher plasma osmolality and haematocrit. Additionally, water-deprived birds had lower defecation rates, suggesting that the mechanisms allowing cecal water absorption may be triggered very rapidly during water-deprivation. Baseline, but not stress-induced corticosterone levels were higher in water-deprived birds. Taken together, these results suggest that ...
Source: Journal of Experimental Biology - January 17, 2020 Category: Biology Authors: Brischoux, F., Beaugeard, E., Mohring, B., Parenteau, C., Angelier, F. Tags: RESEARCH ARTICLE Source Type: research

Experimental evidence for a role of dopamine on avian personality traits [RESEARCH ARTICLE]
Paulo A. Silva, Sandra Trigo, Cristiana I. Marques, Goncalo C. Cardoso, and Marta C. Soares There is increasing interest on the genetic and physiological bases of behavioural differences among individuals, namely animal personality. One particular dopamine (DA) receptor gene (the dopamine receptor D4 gene) has been used as candidate gene to explain personality differences, but with mixed results. Here we use an alternative approach, exogenously manipulating the dopaminergic system and testing for effects on personality assays in a social bird species, the common waxbill (Estrilda astrild). We treated birds with agonists an...
Source: Journal of Experimental Biology - January 17, 2020 Category: Biology Authors: Silva, P. A., Trigo, S., Marques, C. I., Cardoso, G. C., Soares, M. C. Tags: RESEARCH ARTICLE Source Type: research

Effects of intermittent hypoxia on the cell survival and inflammatory responses in the intertidal marine bivalves Mytilus edulis and Crassostrea gigas [RESEARCH ARTICLE]
We examined the molecular markers of autophagy, apoptosis and inflammation during the short-term (1 day) and long-term (6 days) hypoxia and post-hypoxic recovery (1 h) in the mussels and oysters by measuring the lysosomal membrane stability, activity of a key autophagic enzyme (cathepsin D) and mRNA expression of the genes involved in the cellular survival and inflammation, including caspases 2, 3 and 8, Bcl-2, BAX, TGF-β-activated kinase 1 (TAK1), nuclear factor kappa B-1 (NF-B), and NF-B activating kinases IKKα and TBK1. C gigas exhibited higher hypoxia tolerance as well as blunted or delayed inflammatory and ...
Source: Journal of Experimental Biology - January 17, 2020 Category: Biology Authors: Falfushynska, H., Piontkivska, H., Sokolova, I. M. Tags: RESEARCH ARTICLE Source Type: research

A small family business: synergistic and additive effects of the queen and the brood on worker reproduction in a primitively eusocial bee [RESEARCH ARTICLE]
Margarita Orlova, Jesse Starkey, and Etya Amsalem The mechanisms that maintain reproductive division of labor in social insects are still incompletely understood. Most studies focus on the relationship between adults, overlooking another important stakeholder– the juveniles. Recent studies show that not only the queen, but also the brood regulate worker reproduction. However, how the two coordinate to maintain reproductive monopoly remained unexplored. Here, we disentangled the roles of the brood and the queen in primitively eusocial bees (Bombus impatiens) by examining their separated and combined effects on worker ...
Source: Journal of Experimental Biology - January 17, 2020 Category: Biology Authors: Orlova, M., Starkey, J., Amsalem, E. Tags: RESEARCH ARTICLE Source Type: research

Dust and grit matter: abrasives of different size lead to opposing dental microwear textures in experimentally fed sheep (Ovis aries) [RESEARCH ARTICLE]
Nicole L. Ackermans, Daniela E. Winkler, Louise F. Martin, Thomas M. Kaiser, Marcus Clauss, and Jean-Michel Hatt External abrasives ingested along with the herbivore diet are considered main contributors to dental wear, though how different abrasive sizes and concentrations influence wear remains unclear. Dental microwear texture analysis (DMTA) is an established method for dietary reconstruction which describes a tooth's surface topography on a micrometre scale. The method has yielded conflicting results as to the effect of external abrasives. In the present study, a feeding experiment was performed on sheep (Ovis aries),...
Source: Journal of Experimental Biology - January 17, 2020 Category: Biology Authors: Ackermans, N. L., Winkler, D. E., Martin, L. F., Kaiser, T. M., Clauss, M., Hatt, J.-M. Tags: RESEARCH ARTICLE Source Type: research

Suction adhesion in the gliding joint of a cephalopod [RESEARCH ARTICLE]
Andrew M. Smith, Scott M. LaValva, Matthew M. Loiacono, and Joseph T. Thompson We have discovered features of the nuchal joint in the squid, Doryteuthis pealeii, that are unique compared with moveable joints in other animals. The joint's function is unclear but it allows the head to glide toward and away from the mantle. The head glides along the joint with ease yet disarticulating the joint perpendicular to the axis of movement requires considerable force. After disarticulation, the joint components can be repositioned and full function restored immediately. Thus, an unknown attachment mechanism prevents the joint from b...
Source: Journal of Experimental Biology - January 14, 2020 Category: Biology Authors: Smith, A. M., LaValva, S. M., Loiacono, M. M., Thompson, J. T. Tags: RESEARCH ARTICLE Source Type: research

Tracking activity patterns of a multispecies community of gymnotiform weakly electric fish in their neotropical habitat without tagging [RESEARCH ARTICLE]
Jörg Henninger, Rüdiger Krahe, Fabian Sinz, and Jan Benda Field studies on freely behaving animals commonly require tagging and often are focused on single species. Weakly electric fish generate a species- and individual-specific electric organ discharge (EOD) and therefore provide a unique opportunity for individual tracking without tagging. We here present and test tracking algorithms based on recordings with submerged electrode arrays. Harmonic structures extracted from power spectra provide fish identity. Localization of fish based on weighted averages of their EOD amplitudes is found to be more robust than fitting...
Source: Journal of Experimental Biology - January 14, 2020 Category: Biology Authors: Henninger, J., Krahe, R., Sinz, F., Benda, J. Tags: RESEARCH ARTICLE Source Type: research

Leaping small fish out-power breaching whales [INSIDE JEB]
Kathryn Knight (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - January 13, 2020 Category: Biology Authors: Knight, K. Tags: INSIDE JEB Source Type: research

The energetics of 'airtime: estimating swim power from breaching behaviour in fishes and cetaceans [SHORT COMMUNICATION]
Lewis G. Halsey and Gil Iosilevskii Displays of maximum swimming speeds are rare in the laboratory and the wild, limiting our understanding of the top-end athletic capacities of aquatic vertebrates. However, jumps out of the water – exhibited by a diversity of fish and cetaceans – might sometimes represent a behaviour comprising maximum burst effort. We collected data on such breaching behaviour for 14 fish and cetacean species primarily from online videos, to calculate breaching speed. From newly derived formulae based on the drag coefficient and hydrodynamic efficiency, we also calculated the associated powe...
Source: Journal of Experimental Biology - January 13, 2020 Category: Biology Authors: Halsey, L. G., Iosilevskii, G. Tags: SHORT COMMUNICATION Source Type: research

Coding of odour and space in the hemimetabolous insect Periplaneta americana [RESEARCH ARTICLE]
Marco Paoli, Hiroshi Nishino, Einat Couzin-Fuchs, and C. Giovanni Galizia The general architecture of the olfactory system is highly conserved from insects to humans, but neuroanatomical and physiological differences can be observed across species. The American cockroach, inhabiting dark shelters with a rather stable olfactory landscape, is equipped with long antennae used for sampling the surrounding air-space for orientation and navigation. The antennae's exceptional length provides a wide spatial working range for odour detection; however, it is still largely unknown whether and how this is also used for mapping the str...
Source: Journal of Experimental Biology - January 13, 2020 Category: Biology Authors: Paoli, M., Nishino, H., Couzin-Fuchs, E., Galizia, C. G. Tags: RESEARCH ARTICLE Source Type: research

Nociceptive neurons respond to multimodal stimuli in Manduca sexta [RESEARCH ARTICLE]
Daniel P. Caron, Martha Rimniceanu, Anthony E. Scibelli, and Barry A. Trimmer The caterpillar Manduca sexta produces a highly stereotyped strike behavior in response to noxious thermal or mechanical stimuli to the abdomen. This rapid movement is targeted to the site of the stimulus, but the identities of the nociceptive sensory neurons are currently unknown. It is also not known if both mechanical and thermal stimuli are detected by the same neurons. Here we show that the likelihood of a strike increases with the strength of the stimulus and that activity in nerves innervating the body wall increases rapidly in response to...
Source: Journal of Experimental Biology - January 13, 2020 Category: Biology Authors: Caron, D. P., Rimniceanu, M., Scibelli, A. E., Trimmer, B. A. Tags: RESEARCH ARTICLE Source Type: research

A new method for mapping spatial resolution in compound eyes suggests two visual streaks in fiddler crabs [RESEARCH ARTICLE]
Zahra M. Bagheri, Anna-Lee Jessop, Susumu Kato, Julian C. Partridge, Jeremy Shaw, Yuri Ogawa, and Jan M. Hemmi Visual systems play a vital role in guiding the behaviour of animals. Understanding the visual information animals are able to acquire is therefore key to understanding their visually mediated decision making. Compound eyes, the dominant eye type in arthropods, are inherently low-resolution structures. Their ability to resolve spatial detail depends on sampling resolution (interommatidial angle) and the quality of ommatidial optics. Current techniques for estimating interommatidial angles are difficult, and gener...
Source: Journal of Experimental Biology - January 8, 2020 Category: Biology Authors: Bagheri, Z. M., Jessop, A.-L., Kato, S., Partridge, J. C., Shaw, J., Ogawa, Y., Hemmi, J. M. Tags: RESEARCH ARTICLE Source Type: research

Consequences of HSF knockdown on gene expression during the heat shock response in Tigriopus californicus [RESEARCH ARTICLE]
Alice E. Harada and Ronald S. Burton Although the existence of a cellular heat shock response is nearly universal, its relationship to organismal thermal tolerance is not completely understood. Many of the genes involved are known to be regulated by the highly conserved heat shock transcription factor-1 (HSF-1), yet the regulatory network is not fully characterized. Here we investigate the role of HSF-1 in gene expression following thermal stress using knockdown of HSF-1 by RNA interference (RNAi) in the intertidal copepod Tigriopus californicus. We observed some evidence for decreased transcription of heat shock protein g...
Source: Journal of Experimental Biology - January 8, 2020 Category: Biology Authors: Harada, A. E., Burton, R. S. Tags: RESEARCH ARTICLE Source Type: research

Musculoskeletal mass and shape are correlated with competitive ability in male house mice (Mus musculus) [RESEARCH ARTICLE]
Amanda N. Cooper, Christopher B. Cunningham, Jeremy S. Morris, James S. Ruff, Wayne K. Potts, and David R. Carrier Intense physical competition between males for mating opportunities is widespread among mammals. In such agonistic encounters, males with combinations of morphological, physiological, and behavioral characters that allow them to dominate an opponent have greater fitness. However, the specific physical traits associated with competitive ability are poorly understood. Larger body size is often correlated with fitness in mammals. Interestingly, fitness is maximized at intermediate body masses in male house mice (...
Source: Journal of Experimental Biology - January 8, 2020 Category: Biology Authors: Cooper, A. N., Cunningham, C. B., Morris, J. S., Ruff, J. S., Potts, W. K., Carrier, D. R. Tags: RESEARCH ARTICLE Source Type: research

Physiological and pharmacological characterization of a molluscan neuronal efflux transporter; evidence for age-related transporter impairment [SHORT COMMUNICATION]
Petra M. Hermann, Alexander C. Perry, Izen Hamad, and Willem C. Wildering Plasma membrane efflux transporters play crucial roles in the removal and release of harmful but also beneficial substances from the interior of cells and tissue types in virtually every extant species. They contribute to the clearance of a broad spectrum of exogenous and endogenous toxicants and harmful metabolites including the reactive lipid aldehyde byproducts of lipid peroxidation that are a hallmark of cellular aging. Here we tested whether declining transporter functionality may contribute to functional decline in a snail model of neuronal agi...
Source: Journal of Experimental Biology - January 8, 2020 Category: Biology Authors: Hermann, P. M., Perry, A. C., Hamad, I., Wildering, W. C. Tags: SHORT COMMUNICATION Source Type: research

The integration of sensory feedback in the modulation of anuran landing preparation [RESEARCH ARTICLE]
S. M. Cox and G. B. Gillis Controlled landing requires preparation. Mammals and bipedal birds vary how they prepare for landing by predicting the timing and magnitude of impact from the integration of visual and non-visual information. Here we explore how an animal that moves primarily through hopping, Rhinella marina, the cane toad, integrates sensory information to modulate landing preparation. Earlier work suggests toads may modulate landing preparation using predictions of impact timing and/or magnitude based on non-visual sensory feedback during takeoff rather than visual cues about the landing itself. Here we disenta...
Source: Journal of Experimental Biology - January 8, 2020 Category: Biology Authors: Cox, S. M., Gillis, G. B. Tags: RESEARCH ARTICLE Source Type: research

Mitochondrial thermo-sensitivity in invasive and native freshwater mussels [RESEARCH ARTICLE]
In this study, we aimed to characterize the mitochondrial thermo-tolerance in invasive and endemic freshwater mussels. With the use of high-resolution respirometry, we analyzed the mitochondrial respiration of two freshwater bivalve species exposed to a broad range of temperatures. We noticed that the invasive dreissenid Dreissena bugensis possessed a less thermo-tolerant mitochondrial metabolism than the endemic unionid Elliptio complanata. This lack of tolerance was linked with a more noticeable aerobic metabolic depression at elevated temperatures. This decrease in mitochondrial metabolic activity was also linked with a...
Source: Journal of Experimental Biology - January 8, 2020 Category: Biology Authors: Hraoui, G., Bettinazzi, S., Gendron, A. D., Boisclair, D., Breton, S. Tags: RESEARCH ARTICLE Source Type: research

Why do muscles lose torque potential when activated within their agonistic group? [SHORT COMMUNICATION]
In this study, we (1) tested if this loss in torque was accompanied by a corresponding loss in force, thereby testing the potential role of changes in moment arms between conditions; (2) removed all inter-muscular connections between the quadriceps muscles, thus determining the potential role of inter-muscular force transmission; and (3) systematically changed the inter-muscular pressure by performing experiments at different activation/force levels, thereby exploring the possible role of inter-muscular pressure in the loss of torque capacity with simultaneous muscle activation. Experiments were performed in a New Zealand ...
Source: Journal of Experimental Biology - January 7, 2020 Category: Biology Authors: de Brito Fontana, H., de Campos, D., Sawatsky, A., Han, S.-w., Herzog, W. Tags: SHORT COMMUNICATION Source Type: research

Moles power-walk with their thumbs [OUTSIDE JEB]
Christopher Basu (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - January 7, 2020 Category: Biology Authors: Basu, C. Tags: OUTSIDE JEB Source Type: research

A new spin on flight control [OUTSIDE JEB]
Ellen Lesser (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - January 7, 2020 Category: Biology Authors: Lesser, E. Tags: OUTSIDE JEB Source Type: research