Effects of a gut microbiota transfer on emotional reactivity in Japanese quails (Coturnix japonica) [RESEARCH ARTICLE]
This study shows for the first time that a gut microbiota transfer can influence emotional reactivity in Japanese quails strengthening the existence of a microbiota-gut-brain axis in this species of bird. (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - April 11, 2019 Category: Biology Authors: Kraimi, N., Calandreau, L., Zemb, O., Germain, K., Dupont, C., Velge, P., Guitton, E., Lavillatte, S., Parias, C., Leterrier, C. Tags: RESEARCH ARTICLE Source Type: research

Water relations of an insular pit viper [RESEARCH ARTICLE]
Mark R. Sandfoss and Harvey B. Lillywhite Colonization of novel habitats often requires plasticity or adaptation to local conditions. There is a critical need to maintain hydration in terrestrial environments having limited water. Atypical populations of Florida cottonmouth snakes, Agkistrodon conanti, inhabit continental islands with no permanent sources of fresh water. Here we report investigations related to how these insular snakes maintain water balance considering the mainland conspecifics are semi-aquatic and typically associate with freshwater mesic habitats. We tested three hypotheses related to water relations of...
Source: Journal of Experimental Biology - April 11, 2019 Category: Biology Authors: Sandfoss, M. R., Lillywhite, H. B. Tags: RESEARCH ARTICLE Source Type: research

Muscles brake and bend joints to shape wings [INSIDE JEB]
Kathryn Knight (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - April 9, 2019 Category: Biology Authors: Knight, K. Tags: INSIDE JEB Source Type: research

Natural polymorphism in protein kinase G modulates functional senescence in Drosophila melanogaster [RESEARCH ARTICLE]
Stephanie P. Kelly and Ken Dawson-Scully The common fruit fly, Drosophila melanogaster, is a well-characterized model for neurological disorders and is widely used to investigate the biology of aging, stress tolerance and pleiotropy. The foraging (for) gene encodes a cGMP-dependent protein kinase (PKG), which has been implicated in several behavioral phenotypes including feeding, sleep, learning and memory, and environmental stress tolerance. We used the well-established Drosophila activity monitor (DAM) to investigate the effects of the conserved NO/cGMP/PKG signaling pathway on functional senescence. Our results show th...
Source: Journal of Experimental Biology - April 9, 2019 Category: Biology Authors: Kelly, S. P., Dawson-Scully, K. Tags: RESEARCH ARTICLE Source Type: research

Sensory feedback independent pre-song vocalizations correlate with time to song initiation [RESEARCH ARTICLE]
Divya Rao, Satoshi Kojima, and Raghav Rajan The song of the adult male zebra finch is a well-studied example of a learned motor sequence. Song bouts begin with a variable number of introductory notes (INs) before actual song production. Previous studies have shown that INs progress from a variable initial state to a stereotyped final state before each song. This progression is thought to represent motor preparation, but the underlying mechanisms remain poorly understood. Here, we assessed the role of sensory feedback in the progression of INs to song. We found that the mean number of INs before song and the progression of...
Source: Journal of Experimental Biology - April 9, 2019 Category: Biology Authors: Rao, D., Kojima, S., Rajan, R. Tags: Neuroethology RESEARCH ARTICLE Source Type: research

Increased apical sodium-dependent glucose transporter abundance in the ctenidium of the giant clam Tridacna squamosa upon illumination [RESEARCH ARTICLE]
Christabel Y. L. Chan, Kum C. Hiong, Celine Y. L. Choo, Mel V. Boo, Wai P. Wong, Shit F. Chew, and Yuen K. Ip Giant clams contain phototrophic zooxanthellae, and live in nutrient-deficient tropical waters where light is available. We obtained the complete cDNA coding sequence of a homolog of mammalian sodium/glucose cotransporter 1 (SGLT1) – SGLT1-like – from the ctenidium of the fluted giant clam, Tridacna squamosa. SGLT1-like had a host origin and was expressed predominantly in the ctenidium. Molecular characterizations reveal that SGLT1-like of T. squamosa could transport urea, in addition to glucose, as ot...
Source: Journal of Experimental Biology - April 9, 2019 Category: Biology Authors: Chan, C. Y. L., Hiong, K. C., Choo, C. Y. L., Boo, M. V., Wong, W. P., Chew, S. F., Ip, Y. K. Tags: RESEARCH ARTICLE Source Type: research

Variation in sexual brain size dimorphism over the breeding cycle in the three-spined stickleback [RESEARCH ARTICLE]
Severine D. Buechel, Kristina Noreikiene, Jacquelin DeFaveri, Elisavet Toli, Niclas Kolm, and Juha Merilä Snapshot analyses have demonstrated dramatic intraspecific variation in the degree of brain sexual size dimorphism (SSD). Although brain SSD is believed to be generated by the sex-specific cognitive demands of reproduction, the relative roles of developmental and population-specific contributions to variation in brain SSD remain little studied. Using a common garden experiment, we tested for sex-specific changes in brain anatomy over the breeding cycle in three-spined stickleback (Gasterosteus aculeatus) sampled fro...
Source: Journal of Experimental Biology - April 9, 2019 Category: Biology Authors: Buechel, S. D., Noreikiene, K., DeFaveri, J., Toli, E., Kolm, N., Merilä, J. Tags: RESEARCH ARTICLE Source Type: research

Is conservation of center of mass mechanics a priority in human walking? Insights from leg-length asymmetry experiments [RESEARCH ARTICLE]
Kirsty A. McDonald, Daniel Devaprakash, and Jonas Rubenson Center of mass (COM) control has been proposed to serve economy- and stability-related locomotor task objectives. However, given the lack of evidence supporting direct sensing and/or regulation of the COM, it remains unclear whether COM mechanics are prioritized in the control scheme of walking. We posit that peripheral musculoskeletal structures, e.g., muscle, are more realistic control targets than the COM, given their abundance of sensorimotor receptors, and ability to influence whole-body energetics. As a first test of this hypothesis we examined whether conser...
Source: Journal of Experimental Biology - April 9, 2019 Category: Biology Authors: McDonald, K. A., Devaprakash, D., Rubenson, J. Tags: RESEARCH ARTICLE Source Type: research

Respiratory sinus arrhythmia is a major component of HRV in undisturbed, remotely monitored rattlesnakes, Crotalus durissus [RESEARCH ARTICLE]
Pollyana V. W. Sanches, Edwin W. Taylor, Livia M. Duran, Andre L. Cruz, Daniel P. M. Dias, and Cleo A. C. Leite An implanted telemetry device transmitted ECG from the South American rattlesnake, Crotalus durissus, held under stable conditions without restraining cables or interaction with researchers. Mean heart rate (fH) recovered rapidly (
Source: Journal of Experimental Biology - April 9, 2019 Category: Biology Authors: Sanches, P. V. W., Taylor, E. W., Duran, L. M., Cruz, A. L., Dias, D. P. M., Leite, C. A. C. Tags: RESEARCH ARTICLE Source Type: research

Joint angular excursions during cyclical behaviors differ between tetrapod feeding and locomotor systems [RESEARCH ARTICLE]
In this study, we compare average joint angular excursions during cyclic behaviors– chewing, walking and running–in a phylogenetic context to explore differences in the optimality criteria of these two systems. Across 111 tetrapod species, average limb-joint angular excursions during cyclic locomotion are greater and more evolutionarily labile than those of the jaw joint during cyclic chewing. We argue that these findings reflect fundamental functional dichotomies between tetrapod locomotor and feeding systems. Tetrapod chewing systems are optimized for precise application of force over a narrower, more control...
Source: Journal of Experimental Biology - April 9, 2019 Category: Biology Authors: Granatosky, M. C., McElroy, E. J., Laird, M. F., Iriarte-Diaz, J., Reilly, S. M., Taylor, A. B., Ross, C. F. Tags: RESEARCH ARTICLE Source Type: research

Functional morphology of endurance swimming performance and gait transition strategies in balistoid fishes [RESEARCH ARTICLE]
Andrew B. George and Mark W. Westneat Triggerfishes and filefishes (Balistoidea) use balistiform locomotion to power steady swimming with their dorsal and anal fins and transition to a gait dominated by body and caudal fin (BCF) kinematics at high speeds. Fin and body shapes are predicted to be strong determinants of swimming performance and gait transitions. The goal of this study was to combine morphometrics and critical swimming tests to explore relationships between fin and body shapes and swimming performance in a phylogenetic context in order to understand the evolution of balistiform swimming. Among 13 species of ba...
Source: Journal of Experimental Biology - April 8, 2019 Category: Biology Authors: George, A. B., Westneat, M. W. Tags: RESEARCH ARTICLE Source Type: research

Cranial kinesis in the miniaturised lizard Ablepharus kitaibelii (Squamata: Scincidae) [RESEARCH ARTICLE]
Stephan Handschuh, Nikolay Natchev, Stefan Kummer, Christian J. Beisser, Patrick Lemell, Anthony Herrel, and Vladislav Vergilov Cranial kinesis refers to intracranial movements in the vertebrate skull that do not concern the jaw joint, the middle ear, or the hypobranchial skeleton. Different kinds of cranial kinesis have been reported for lizards, including mesokinesis, metakinesis, amphikinesis (simultaneous meso- and metakinesis), and streptostyly. Streptostyly is considered relatively widespread within lizards, while mesokinesis has been documented only for geckos, varanids, and anguids. The present study investigates c...
Source: Journal of Experimental Biology - April 8, 2019 Category: Biology Authors: Handschuh, S., Natchev, N., Kummer, S., Beisser, C. J., Lemell, P., Herrel, A., Vergilov, V. Tags: RESEARCH ARTICLE Source Type: research

Cost of transport is a repeatable trait but is not determined by mitochondrial efficiency in zebrafish (Danio rerio) [RESEARCH ARTICLE]
Miki Jahn and Frank Seebacher The energy used to move a given distance (cost of transport; CoT) varies significantly between individuals of the same species. A lower CoT allows animals to allocate more of their energy budget to growth and reproduction. A higher CoT may cause animals to adjust their movement across different environmental gradients to reduce energy allocated to movement. The aim of this project was to determine whether CoT is a repeatable trait within individuals, and to determine its physiological causes and ecological consequences. We found that the CoT is a repeatable trait in zebrafish (Danio rerio). We...
Source: Journal of Experimental Biology - April 8, 2019 Category: Biology Authors: Jahn, M., Seebacher, F. Tags: RESEARCH ARTICLE Source Type: research

Pollen is essential for health of honey bee gut bugs [INSIDE JEB]
Kathryn Knight (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - April 5, 2019 Category: Biology Authors: Knight, K. Tags: INSIDE JEB Source Type: research

Pollen reverses decreased lifespan, altered nutritional metabolism and suppressed immunity in honey bees (Apis mellifera) treated with antibiotics [RESEARCH ARTICLE]
In this study, newly emerged worker bees were subjected to four diets that contained (1) pollen, (2) pollen and antibiotics, (3) neither pollen nor antibiotics or (4) antibiotics alone. The expression level of two nutrition genes target of rapamycin (tor) and insulin like peptide (ilp1), one nutritional marker gene vitellogenin (vg), five major royal jelly protein genes (mrjp1–5), one antimicrobial peptide regulating gene relish (rel), and DWV virus titer and its replication intermediate, negative RNA strand, were determined by qRT-PCR from the honey bees at 7 days post-antibiotic treatment. Additionally, honey ...
Source: Journal of Experimental Biology - April 5, 2019 Category: Biology Authors: Li, J., Heerman, M. C., Evans, J. D., Rose, R., Li, W., Rodriguez-Garcia, C., DeGrandi-Hoffman, G., Zhao, Y., Huang, S., Li, Z., Hamilton, M., Chen, Y. Tags: RESEARCH ARTICLE Source Type: research

Work loop dynamics of the pigeon (Columba livia) humerotriceps demonstrate potentially diverse roles for active wing morphing [RESEARCH ARTICLE]
Jolan S. Theriault, Joseph W. Bahlman, Robert E. Shadwick, and Douglas L. Altshuler Control of wing shape is believed to be a key feature that allows most birds to produce aerodynamically efficient flight behaviors and high maneuverability. Anatomical organization of intrinsic wing muscles suggests specific roles for the different motor elements in wing shape modulation, but testing these hypothesized functions requires challenging measurements of muscle activation and strain patterns, and force dynamics. The wing muscles that have been best characterized during flight are the elbow muscles of the pigeon (Columba livia). ...
Source: Journal of Experimental Biology - April 5, 2019 Category: Biology Authors: Theriault, J. S., Bahlman, J. W., Shadwick, R. E., Altshuler, D. L. Tags: Comparative biomechanics of movement RESEARCH ARTICLE Source Type: research

Stiffness gradients facilitate ovipositor bending and spatial probing control in a parasitic wasp [RESEARCH ARTICLE]
U. Cerkvenik, J.L. van Leeuwen, A. Kovalev, S. N. Gorb, Y. Matsumura, and S. W. S Gussekloo Many parasitic wasps use slender and steerable ovipositors to lay eggs in hosts hidden in substrates, but it is currently unknown how steering is achieved. The ovipositors generally consist of three longitudinally connected elements, one dorsal and two ventral valves that can slide along each other. For the parasitic wasp Diachasmimorpha longicaudata, it has been shown that protraction of the ventral valves causes incurving of the ventral valves towards the dorsal one, which results in a change in probing direction. We hypothesise t...
Source: Journal of Experimental Biology - April 5, 2019 Category: Biology Authors: Cerkvenik, U., van Leeuwen, J. L., Kovalev, A., Gorb, S. N., Matsumura, Y., Gussekloo, S. W. S. Tags: RESEARCH ARTICLE Source Type: research

Enhanced transports of nutrients powered by microscale flows of self-spinning dinoflagellate Symbiodinium [RESEARCH ARTICLE]
Zheng Zhu and Quan-Xing Liu The metabolism of a living organism (bacteria, algae, zooplankton) requires a continuous uptake of nutrients from the surrounding environment. However, within local-spatial scales, the nutrients are quickly used up under dense concentration of organisms. Here we report that self-spinning dinoflagellate Symbiodinium sp. (clade E) generate a microscale flows that mitigates competition and enhances the uptake of nutrients from the surrounding environment. Our experimental and theoretical results reveal that this incessant active behavior enhances transports by about 80-fold when compared to Brownia...
Source: Journal of Experimental Biology - April 5, 2019 Category: Biology Authors: Zhu, Z., Liu, Q.-X. Tags: RESEARCH ARTICLE Source Type: research

Mantis shrimp fine-tune ballistic blows [INSIDE JEB]
Kathryn Knight (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - April 4, 2019 Category: Biology Authors: Knight, K. Tags: INSIDE JEB Source Type: research

Mystery of how aquatic insects breathe in aquifers solved [INSIDE JEB]
Kathryn Knight (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - April 4, 2019 Category: Biology Authors: Knight, K. Tags: INSIDE JEB Source Type: research

Context-dependent scaling of kinematics and energetics during contests and feeding in mantis shrimp [RESEARCH ARTICLE]
P. A. Green, M. J. McHenry, and S. N. Patek Measurements of energy use, and its scaling with size, are critical to understanding how organisms accomplish myriad tasks. For example, energy budgets are central to game theory models of assessment during contests and underlie patterns of feeding behavior. Clear tests connecting energy to behavioral theory require measurements of the energy use of single individuals for particular behaviors. Many species of mantis shrimp (Stomatopoda: Crustacea) use elastic energy storage to power high-speed strikes that they deliver to opponents during territorial contests and to hard–s...
Source: Journal of Experimental Biology - April 4, 2019 Category: Biology Authors: Green, P. A., McHenry, M. J., Patek, S. N. Tags: RESEARCH ARTICLE Source Type: research

Cutaneous respiration by diving beetles from underground aquifers of Western Australia (Coleoptera: Dytiscidae) [RESEARCH ARTICLE]
Karl K. Jones, Steven J. B. Cooper, and Roger S. Seymour Insects have a gas-filled respiratory system, which provides a challenge for those that have become aquatic secondarily. Diving beetles (Dytiscidae) use bubbles on the surface of their bodies to supply O2 for their dives and passively gain O2 from the water. However, these bubbles usually require replenishment at the water's surface. A highly diverse assemblage of subterranean dytiscids has evolved in isolated calcrete aquifers of Western Australia with limited/no access to an air–water interface, raising the question of how they are able to respire. We explor...
Source: Journal of Experimental Biology - April 4, 2019 Category: Biology Authors: Jones, K. K., Cooper, S. J. B., Seymour, R. S. Tags: RESEARCH ARTICLE Source Type: research

Loss-of-function approaches in comparative physiology: is there a future for knockdown experiments in the era of genome editing? [COMMENTARY]
Alex M. Zimmer, Yihang K. Pan, Theanuga Chandrapalan, Raymond W. M. Kwong, and Steve F. Perry Loss-of-function technologies, such as morpholino- and RNAi-mediated gene knockdown, and TALEN- and CRISPR/Cas9-mediated gene knockout, are widely used to investigate gene function and its physiological significance. Here, we provide a general overview of the various knockdown and knockout technologies commonly used in comparative physiology and discuss the merits and drawbacks of these technologies with a particular focus on research conducted in zebrafish. Despite their widespread use, there is an ongoing debate surrounding the...
Source: Journal of Experimental Biology - April 4, 2019 Category: Biology Authors: Zimmer, A. M., Pan, Y. K., Chandrapalan, T., Kwong, R. W. M., Perry, S. F. Tags: COMMENTARY Source Type: research

Key hormones disappear early from egg [INSIDE JEB]
Kathryn Knight (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - April 3, 2019 Category: Biology Authors: Knight, K. Tags: INSIDE JEB Source Type: research

Stubborn insects stick to regular walk when scaling slopes [INSIDE JEB]
Kathryn Knight (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - April 3, 2019 Category: Biology Authors: Knight, K. Tags: INSIDE JEB Source Type: research

Interspecific scaling of blood flow rates and arterial sizes in mammals [RESEARCH ARTICLE]
Roger S. Seymour, Qiaohui Hu, Edward P. Snelling, and Craig R. White This meta-study investigated the relationships between blood flow rate (Q; cm3 s–1), wall shear stress (w; dyn cm–2) and lumen radius (ri; cm) in 20 named systemic arteries of nine species of mammals, ranging in mass from 23 g mice to 652 kg cows, at rest. In the dataset, derived from 50 studies, lumen radius varied between 3.7 µm in a cremaster artery of a rat and 11.2 mm in the aorta of a human. The 92 logged data points of and ri are described by a single second-order polynomial curve with the equation...
Source: Journal of Experimental Biology - April 3, 2019 Category: Biology Authors: Seymour, R. S., Hu, Q., Snelling, E. P., White, C. R. Tags: RESEARCH ARTICLE Source Type: research

The quantity-quality trade-off: differential effects of daily food availability times on reproductive performance and offspring quality in diurnal zebra finches [RESEARCH ARTICLE]
Ila Mishra and Vinod Kumar An abundant food supply is crucial to reproductive performance, as shown by restricted food availability experiments, in small-sized vertebrates including birds. However, whether daily feeding times affect reproduction is largely unknown. The present study investigated the effects of daily food availability times on reproductive performance and quality of eggs and offspring survivors in zebra finches (Taeniopygia guttata). In randomly paired birds kept under a 12 h:12 h light:dark cycle for about 52 weeks, food availability period was restricted to 4 h in the morning [morning...
Source: Journal of Experimental Biology - April 3, 2019 Category: Biology Authors: Mishra, I., Kumar, V. 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 melanin: eumelanins yield blackish hues, whereas pheomelanins yield reddish hues. The production of eumelanins requires low levels of glutathione (GSH), which is the most important intracellular antioxidant, whereas the production of pheomelanins requires high levels of GSH. We investigated the oxidative status of male pied flycatchers (Ficed...
Source: Journal of Experimental Biology - April 3, 2019 Category: Biology Authors: Teerikorpi, P. E., Stauffer, J., Ilmonen, P., Calhim, S., Schuett, W., Laaksonen, T. Tags: RESEARCH ARTICLE Source Type: research

Avian yolk androgens are metabolized rather than taken up by the embryo during the first days of incubation [RESEARCH ARTICLE]
Neeraj Kumar, Annie van Dam, Hjalmar Permentier, Martijn van Faassen, Ido Kema, Manfred Gahr, and Ton G. G. Groothuis Several studies show effects of yolk androgens in avian eggs on the phenotype of the offspring. Yolk hormone concentrations decline strongly within the first few days of incubation. Although early embryonic uptake of yolk androgens is suggested by the presence of radioactivity in the embryo when eggs are injected with radiolabelled androgens, these studies do not verify the chemical identity of radioactive compound(s), although it is known that these androgens can be metabolized substantially. By using sta...
Source: Journal of Experimental Biology - April 3, 2019 Category: Biology Authors: Kumar, N., van Dam, A., Permentier, H., van Faassen, M., Kema, I., Gahr, M., Groothuis, T. G. G. Tags: RESEARCH ARTICLE Source Type: research

Motor control of an insect leg during level and incline walking [RESEARCH ARTICLE]
Chris J. Dallmann, Volker Dürr, and Josef Schmitz During walking, the leg motor system must continually adjust to changes in mechanical conditions, such as the inclination of the ground. To understand the underlying control, it is important to know how changes in leg muscle activity relate to leg kinematics (movements) and leg dynamics (forces, torques). Here, we studied these parameters in hindlegs of stick insects (Carausius morosus) during level and uphill/downhill (±45 deg) walking, using a combination of electromyography, 3D motion capture and ground reaction force measurements. We find that some kinema...
Source: Journal of Experimental Biology - April 3, 2019 Category: Biology Authors: Dallmann, C. J., Dürr, V., Schmitz, J. Tags: Comparative biomechanics of movement RESEARCH ARTICLE Source Type: research

Loss of angiotensin-converting enzyme-related (ACER) peptidase disrupts behavioural and metabolic responses to diet in Drosophila melanogaster [RESEARCH ARTICLE]
Zoe Glover, Matthew D. Hodges, Nikolett Dravecz, Jack Cameron, Helen Askwith, Alan Shirras, and Susan J. Broughton Drosophila Acer (Angiotensin-converting enzyme-related) encodes a member of the angiotensin-converting enzyme (ACE) family of metallopeptidases that in mammals play roles in the endocrine regulation of blood homeostasis. ACE is also expressed in adipose tissue where it is thought to play a role in metabolic regulation. Drosophila Acer is expressed in the adult fat body of the head and abdomen and is secreted into the haemolymph. Acer null mutants have previously been found to have reduced night time sleep and ...
Source: Journal of Experimental Biology - April 2, 2019 Category: Biology Authors: Glover, Z., Hodges, M. D., Dravecz, N., Cameron, J., Askwith, H., Shirras, A., Broughton, S. J. Tags: RESEARCH ARTICLE Source Type: research

Using stable isotope analysis to study skin mucus exudation and renewal in fish [METHODS [amp ] TECHNIQUES]
Antoni Ibarz, Borja Ordonez-Grande, Ignasi Sanahuja, Sergio Sanchez-Nuno, Jaume Fernandez-Borras, Josefina Blasco, and Laura Fernandez-Alacid Fish skin mucus is proposed as a novel target for the study of physiological condition and to conduct minimally invasive monitoring of fish. Whereas mucus composition has been a major interest of recent studies, no practical techniques have been proposed to gain understanding of the capacity and rhythm of production and exudation. Here, we use stable isotope analysis (SIA) with a labelled meal, packaged in gelatin capsules, to evaluate mucus production and renewal in a fish model, th...
Source: Journal of Experimental Biology - April 2, 2019 Category: Biology Authors: Ibarz, A., Ordonez-Grande, B., Sanahuja, I., Sanchez-Nuno, S., Fernandez-Borras, J., Blasco, J., Fernandez-Alacid, L. Tags: METHODS [amp ] TECHNIQUES Source Type: research

Responses of compass neurons in the locust brain to visual motion and leg motor activity [RESEARCH ARTICLE]
Ronny Rosner, Uta Pegel, and Uwe Homberg The central complex, a group of midline neuropils in the insect brain, plays a key role in spatial orientation and navigation. Work in locusts, crickets, dung beetles, bees, and butterflies suggests that it harbors a network of neurons which determines the orientation of the insect relative to the pattern of polarized light in the blue sky. In locusts, these compass cells also respond to simulated approaching objects. Here we investigate in the locust Schistocerca gregaria whether compass cells change their activity when the animal experiences large-field visual motion or when the a...
Source: Journal of Experimental Biology - April 2, 2019 Category: Biology Authors: Rosner, R., Pegel, U., Homberg, U. 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 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 (R–L) shunt – serves to deliver CO2-rich blood with protons needed...
Source: Journal of Experimental Biology - April 1, 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

Small zooplankton rings the alarm for oxygen loss in big oceans [OUTSIDE JEB]
Yangfan Zhang (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - April 1, 2019 Category: Biology Authors: Zhang, Y. Tags: OUTSIDE JEB Source Type: research

Control of breathing and respiratory gas exchange in high-altitude ducks native to the Andes [RESEARCH ARTICLE]
We examined the control of breathing and respiratory gas exchange in six species of high-altitude duck that independently colonized the high Andes. We compared ducks from high-altitude populations in Peru (Lake Titicaca at ~3800 m above sea level; Chancay River at ~3000–4100 m) with closely related populations or species from low altitude. Hypoxic ventilatory responses were measured shortly after capture at the native altitude. In general, ducks responded to acute hypoxia with robust increases in total ventilation and pulmonary O2 extraction. O2 consumption rates were maintained or increased slightly in acu...
Source: Journal of Experimental Biology - April 1, 2019 Category: Biology Authors: Ivy, C. M., Lague, S. L., York, J. M., Chua, B. A., Alza, L., Cheek, R., Dawson, N. J., Frappell, P. B., McCracken, K. G., Milsom, W. K., Scott, G. R. 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, so Ca2+ from surface CRUs (peripheral couplings, PCs) must diffuse to internal CRU sites of the corbular SR (cSR) during ce...
Source: Journal of Experimental Biology - April 1, 2019 Category: Biology Authors: Sheard, T. M. D., Kharche, S. R., Pinali, C., Shiels, H. A. Tags: RESEARCH ARTICLE Source Type: research

Softness sensing and learning in Drosophila larvae [RESEARCH ARTICLE]
We report that larvae can discriminate between different agar concentrations and prefer softer agar. Interestingly, we show that larvae on a harder surface search for a softer surface using memory associated with an odor, and that they evaluate foods by balancing softness and sweetness. These findings suggest that larvae integrate mechanosensory information with chemosensory input while foraging. Moreover, we found that the larval preference for softness is affected by genetic background. (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - April 1, 2019 Category: Biology Authors: Kudow, N., Kamikouchi, A., Tanimura, T. Tags: RESEARCH ARTICLE Source Type: research

Morph- and sex-specific effects of challenging conditions on maintenance parameters in the Gouldian finch [RESEARCH ARTICLE]
Rita Fragueira, Simon Verhulst, and Michaël Beaulieu Intraspecific discrete polymorphism is associated with the use of alternative life-history strategies, reflected by distinct reproductive or copying strategies in individuals of different morphs. Yet, morph-specific costs and benefits related to different life-history strategies remain unclear. Here, we examined in the polymorphic Gouldian finch (Erythrura gouldiae) whether markers of somatic maintenance (body mass, oxidative status and telomere length) differed between red- and black-headed birds under energetically demanding conditions (during heatwaves of different...
Source: Journal of Experimental Biology - April 1, 2019 Category: Biology Authors: Fragueira, R., Verhulst, S., Beaulieu, M. Tags: Ecophysiology: responses to environmental stressors and change RESEARCH ARTICLE Source Type: research

Genetic and environmental effects on the scaling of metabolic rate with body size [RESEARCH ARTICLE]
Erlend I. F. Fossen, Christophe Pelabon, and Sigurd Einum Metabolic rate (MR) often scales with body mass (BM) following a power function of the form MR=aBMb, where log(a) is the allometric intercept and b is the allometric exponent (i.e. slope on a log–log scale). The variational properties of b have been debated, but very few studies have tested for genetic variance in b, and none have tested for a genotype-by-environment (GxE) interaction in b. Consequently, the short-term evolutionary potentials of both b and its phenotypic plasticity remain unknown. Using 10 clones of a population of Daphnia magna, we estimated...
Source: Journal of Experimental Biology - April 1, 2019 Category: Biology Authors: Fossen, E. I. F., Pelabon, C., Einum, S. Tags: RESEARCH ARTICLE Source Type: research

Insects that stink and hatch in sync [OUTSIDE JEB]
Ilan Ruhr (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - April 1, 2019 Category: Biology Authors: Ruhr, I. Tags: OUTSIDE JEB Source Type: research

A spider's decision depends on its thirst [OUTSIDE JEB]
Julia Nowack (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - April 1, 2019 Category: Biology Authors: Nowack, J. Tags: OUTSIDE JEB Source Type: research

Fish fitness is on the rocks [OUTSIDE JEB]
Alex Evans (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - April 1, 2019 Category: Biology Authors: Evans, A. Tags: OUTSIDE JEB Source Type: research

Zonation of Ca2+ transport and enzyme activity in the caeca of rainbow trout - a simple structure with complex functions [RESEARCH ARTICLE]
Melanie Williams, Domenico Barranca, and Carol Bucking Trout caeca are vermiform structures projecting from the anterior intestine of the gastrointestinal tract. Despite their simple gross morphology, these appendages are physically distinct along the anterior–posterior axis, and ultrastructural evidence suggests zonation of function within the structures. Individual caeca from three sections (anterior, middle and posterior) were removed from the intestine of freshwater rainbow trout and investigated for ion transport and enzyme activity. Ca2+ absorption appeared as a combination of active and passive movement, with...
Source: Journal of Experimental Biology - April 1, 2019 Category: Biology Authors: Williams, M., Barranca, D., Bucking, C. Tags: RESEARCH ARTICLE Source Type: research

Snakes partition their body to traverse large steps stably [RESEARCH ARTICLE]
Sean W. Gart, Thomas W. Mitchel, and Chen Li Many snakes live in deserts, forests, and river valleys and traverse challenging 3-D terrain like rocks, felled trees, and rubble, with obstacles as large as themselves and variable surface properties. By contrast, apart from branch cantilevering, burrowing, swimming, and gliding, laboratory studies of snake locomotion focused on that on simple flat surfaces. Here, to begin to understand snake locomotion in complex 3-D terrain, we study how the variable kingsnake, a terrestrial generalist, traversed a large step of variable surface friction and step height (up to 30% snout-vent ...
Source: Journal of Experimental Biology - April 1, 2019 Category: Biology Authors: Gart, S. W., Mitchel, T. W., Li, C. Tags: RESEARCH ARTICLE Source Type: research

Echolocating bats inspect and discriminate landmark features to guide navigation [RESEARCH ARTICLE]
Chao Yu, Jinhong Luo, Melville Wohlgemuth, and Cynthia F. Moss Landmark-guided navigation is a common behavioral strategy for way-finding, yet prior studies have not examined how animals collect sensory information to discriminate landmark features. We investigated this question in animals that rely on active sensing to guide navigation. Four echolocating bats (Eptesicus fuscus) were trained to use an acoustic landmark to find and navigate through a net opening for a food reward. In experimental trials, an object serving as a landmark was placed adjacent to a net opening and a distractor object next to a barrier (covered o...
Source: Journal of Experimental Biology - April 1, 2019 Category: Biology Authors: Yu, C., Luo, J., Wohlgemuth, M., Moss, C. F. Tags: RESEARCH ARTICLE Source Type: research

Variation in sexual brain size dimorphism over the breeding cycle in the three-spined stickleback [RESEARCH ARTICLE]
Severine D. Buechel, Kristina Noreikiene, Jacquelin DeFaveri, Elisavet Toli, Niclas Kolm, and Juha Merilä Snapshot analyses have demonstrated dramatic intraspecific variation in the degree of brain sexual size dimorphism (SSD). Although brain SSD is believed to be generated by the sex-specific cognitive demands of reproduction, the relative roles of developmental and population specific contributions to variation in brain SSD remain little studied. Using a common garden experiment, we tested for sex-specific changes in brain anatomy over the breeding cycle in three-spined stickleback (Gasterosteus aculeatus) sampled from...
Source: Journal of Experimental Biology - April 1, 2019 Category: Biology Authors: Buechel, S. D., Noreikiene, K., DeFaveri, J., Toli, E., Kolm, N., Merilä, J. Tags: RESEARCH ARTICLE Source Type: research

Phenotypic plasticity in locomotor performance of a monophyletic group of weevils accords with the warmer is better hypothesis [RESEARCH ARTICLE]
In this study, we test the full suite of hypotheses by investigating acclimation responses of locomotor performance for nine populations of five species of sub-Antarctic weevils, using static and fluctuating temperatures. Species showed typical locomotion thermal performance curves with temperature of the maximum speed (Topt) ranging between 22.3±1.7°C (mean±s.e.) and 31.1±0.7°C. For most species Topt was not affected by acclimation. For maximum speed (Umax), significant, positive effects of acclimation were found for all species except a supralittoral one. Individuals acclimated to 0°C sho...
Source: Journal of Experimental Biology - April 1, 2019 Category: Biology Authors: Treasure, A. M., Chown, S. L. Tags: RESEARCH ARTICLE Source Type: research

Evidence for absence of bilateral transfer of olfactory learned information in Apis dorsata and Apis mellifera [RESEARCH ARTICLE]
Meenakshi Vijaykumar, Sandhya Mogily, Aparna Dutta-Gupta, and Joby Joseph Capacity and condition under which the lateral transfer of olfactory memory is possible in insects is still debated. Here, we present evidence in two species of honeybees Apis mellifera and Apis dorsata, consistent with lack of ability to transfer olfactory associative memory, in a PER associative conditioning paradigm, where the untrained antenna is blocked by an insulating coat. We show that the olfactory system on each side of the bee can learn and retrieve information independently and the retrieval using the antenna on the side contralateral to ...
Source: Journal of Experimental Biology - April 1, 2019 Category: Biology Authors: Vijaykumar, M., Mogily, S., Dutta-Gupta, A., Joseph, J. Tags: RESEARCH ARTICLE Source Type: research

Hypoxia tolerance of giant-axon-mediated escape jetting in California market squid (Doryteuthis opalescens) [RESEARCH ARTICLE]
Diana H. Li and William F. Gilly Squids display a wide range of swimming behaviors, including powerful escape-jets mediated by the giant axon system. For California market squid (Doryteuthis opalescens), maintaining essential behaviors like the escape response during environmental variations poses a major challenge since this species often encounters intrusions of cold, hypoxic offshore waters in its coastal spawning habitats. To explore the effects of hypoxia on locomotion and underlying neural mechanisms, we made in vivo recordings of giant axon activity and simultaneous pressure inside the mantle cavity during escape je...
Source: Journal of Experimental Biology - April 1, 2019 Category: Biology Authors: Li, D. H., Gilly, W. F. Tags: RESEARCH ARTICLE Source Type: research