Age-related pharmacodynamics in a bumblebee-microsporidian system mirror similar patterns in vertebrates [RESEARCH ARTICLE]
Arran J. Folly, Philip C. Stevenson, and Mark J. F. Brown Immune systems provide a key defence against diseases. However, they are not a panacea and so both vertebrates and invertebrates co-opt naturally occurring bioactive compounds to treat themselves against parasites and pathogens. In vertebrates, this co-option is complex, with pharmacodynamics leading to differential effects of treatment at different life stages, which may reflect age-linked differences in the immune system. However, our understanding of pharmacodynamics in invertebrates is almost non-existent. Critically, this knowledge may elucidate broad parallel...
Source: Journal of Experimental Biology - March 25, 2020 Category: Biology Authors: Folly, A. J., Stevenson, P. C., Brown, M. J. F. Tags: RESEARCH ARTICLE Source Type: research

Photoperiodic regulation in a wild-derived mouse strain [RESEARCH ARTICLE]
The objective of this study was to characterize the effects of photoperiodic variation on metabolic and reproductive traits, and the related changes in pituitary–hypothalamic gene expression in MSM mice. MSM mice were kept in long (LP) or short photoperiod (SP) for 6 weeks. Our results demonstrate that MSM mice kept in LP, as compared with mice kept in SP, display higher expression of genes encoding thyrotropin (TSH) in the pars tuberalis, thyroid hormone deiodinase 2 (dio2) in the tanycytes and RFamide-related peptide (RFRP3) in the hypothalamus, and lower expression of dio3 in the tanycytes, along with larger ...
Source: Journal of Experimental Biology - March 25, 2020 Category: Biology Authors: Saenz de Miera, C., Beymer, M., Routledge, K., Krol, E., Selman, C., Hazlerigg, D. G., Simonneaux, V. Tags: RESEARCH ARTICLE Source Type: research

Visual determinants of prey chasing behavior in a mudflat crab [RESEARCH ARTICLE]
Brian Gancedo, Carla Salido, and Daniel Tomsic The crab Neohelice granulata inhabits mudflats where it is preyed upon by gulls and, conversely, preys on smaller crabs. Therefore, on seeing moving stimuli, this crab can behave as prey or predator. The crab escape response to visual stimuli has been extensively investigated from the behavioral to the neuronal level. The predatory response (PR), however, has not yet been explored. Here, we show that this response can be reliably elicited and investigated in a laboratory arena. By using dummies of three different sizes moved on the ground at three different velocities over mu...
Source: Journal of Experimental Biology - March 25, 2020 Category: Biology Authors: Gancedo, B., Salido, C., Tomsic, D. Tags: Neuroethology RESEARCH ARTICLE Source Type: research

The sarcomere force-length relationship in an intact muscle-tendon unit [RESEARCH ARTICLE]
Eng Kuan Moo, Timothy R. Leonard, and Walter Herzog The periodic striation pattern in skeletal muscle reflects the length of the basic contractile unit: the sarcomere. More than half a century ago, Gordon, Huxley and Julian provided strong support for the ‘sliding filament’ theory through experiments with single muscle fibres. The sarcomere force–length (FL) relationship has since been extrapolated to whole muscles in an attempt to unravel in vivo muscle function. However, these extrapolations were frequently associated with non-trivial assumptions, such as muscle length changes corresponding linearly to...
Source: Journal of Experimental Biology - March 25, 2020 Category: Biology Authors: Moo, E. K., Leonard, T. R., Herzog, W. Tags: RESEARCH ARTICLE Source Type: research

Acclimatization in the physiological performance of an introduced ectotherm [RESEARCH ARTICLE]
Lauren K. Neel, John D. Curlis, Chase T. Kinsey, Christian L. Cox, and Lance D. McBrayer Phenotypic flexibility may facilitate range expansion by allowing organisms to maintain high levels of performance when introduced to novel environments. Phenotypic flexibility, such as reversible acclimatization, permits organisms to achieve high performance over a wide range of environmental conditions, without the costly allocation or acquisition tradeoffs associated with behavioral thermoregulation, which may expedite range expansion in introduced species. The northern curly-tailed lizard, Leiocephalus carinatus, was introduced to...
Source: Journal of Experimental Biology - March 25, 2020 Category: Biology Authors: Neel, L. K., Curlis, J. D., Kinsey, C. T., Cox, C. L., McBrayer, L. D. Tags: RESEARCH ARTICLE Source Type: research

First two weeks crucial for white-nose syndrome survivors [INSIDE JEB]
Kathryn Knight (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - March 23, 2020 Category: Biology Authors: Knight, K. Tags: INSIDE JEB Source Type: research

Disease recovery in bats affected by white-nose syndrome [RESEARCH ARTICLE]
Nathan W. Fuller, Liam P. McGuire, Evan L. Pannkuk, Todd Blute, Catherine G. Haase, Heather W. Mayberry, Thomas S. Risch, and Craig K. R. Willis Processes associated with recovery of survivors are understudied components of wildlife infectious diseases. White-nose syndrome (WNS) in bats provides an opportunity to study recovery of disease survivors, understand implications of recovery for individual energetics, and assess the role of survivors in pathogen transmission. We documented temporal patterns of recovery from WNS in little brown bats (Myotis lucifugus) following hibernation to test the hypotheses that: (1) recover...
Source: Journal of Experimental Biology - March 23, 2020 Category: Biology Authors: Fuller, N. W., McGuire, L. P., Pannkuk, E. L., Blute, T., Haase, C. G., Mayberry, H. W., Risch, T. S., Willis, C. K. R. Tags: RESEARCH ARTICLE Source Type: research

Human recreation decreases antibody titres in bird nestlings: an overlooked transgenerational effect of disturbance [RESEARCH ARTICLE]
In this study, using Eurasian blue and great tit offspring (Cyanistes caeruleus and Parus major) as model species, we experimentally tested whether human recreation induces changes in the amount of circulating antibodies in young nestlings and whether this effect is modulated by habitat and competition. Moreover, we investigated whether these variations in antibody titres have, in turn, an impact on hatching success and offspring growth. Nestlings of great tit females, which had been disturbed by experimental human recreation during egg-laying, had lower antibody titres compared to control nestlings. Antibody titres of nes...
Source: Journal of Experimental Biology - March 23, 2020 Category: Biology Authors: Bötsch, Y., Tablado, Z., Almasi, B., Jenni, L. Tags: RESEARCH ARTICLE Source Type: research

The variable presence of apoptosis in the testes of diploid and sterile allotetraploid Cobitis (Teleostei, Cobitidae) males during reproductive cycle [SHORT COMMUNICATION]
Olga Jablonska, Dorota Juchno, Anna Leska, Karolina Kowalewska, and Alicja Boron Cobitis species exist in diploid populations, but mostly they occur in diploid-polyploid (d-p) ones. They are considered an important model organism to study biology and physiology of natural hybrid and polyploid vertebrates. Indeed, polyploidization causes a huge stress for the cell physiology and alter spermatogenesis in polyploid fish. The most extensively studied modes of germ cell death during spermatogenesis in vertebrates is apoptosis. The aim of the study was to examine the caspase-3 immunoexpression in the testes of Cobitis taenia fro...
Source: Journal of Experimental Biology - March 23, 2020 Category: Biology Authors: Jablonska, O., Juchno, D., Leska, A., Kowalewska, K., Boron, A. Tags: SHORT COMMUNICATION Source Type: research

Nanometer-scale structure differences in the myofilament lattice spacing of two cockroach leg muscles correspond to their different functions [RESEARCH ARTICLE]
Travis Carver Tune, Weikang Ma, Thomas Irving, and Simon Sponberg Muscle is highly organized across multiple length scales. Consequently, small changes in the arrangement of myofilaments can influence macroscopic mechanical function. Two leg muscles of a cockroach, have identical innervation, mass, twitch responses, length-tension curves, and force-velocity relationships. However, during running, one muscle is dissipative (a "brake"), while the other dissipates and produces significant positive mechanical work (bifunctional). Using time resolved x-ray diffraction in intact, contracting muscle, we simultaneously m...
Source: Journal of Experimental Biology - March 23, 2020 Category: Biology Authors: Tune, T. C., Ma, W., Irving, T., Sponberg, S. Tags: RESEARCH ARTICLE Source Type: research

Shift in worker physiology and gene expression pattern from reproductive to diapause-like with colony age in the bumble bee Bombus impatiens [RESEARCH ARTICLE]
In this study we examined whether workers of the eusocial bumble bee Bombus impatiens maintained a seasonal signature when kept in captivity. We used an integrative approach and compared worker egg-laying, ovarian activation, body size and mass, lipid content in the fat body, cold tolerance and expression of genes related to cold tolerance, metabolism, and stress throughout colony development.We found that bumble bee worker physiology and gene expression patterns shift from reproductive-like to diapause-like as the colony ages. Workers eclosing early in the colony cycle had increased egg-laying and ovarian activation, and ...
Source: Journal of Experimental Biology - March 23, 2020 Category: Biology Authors: Treanore, E. D., Kiner, J. M., Kerner, M. E., Amsalem, E. Tags: RESEARCH ARTICLE Source Type: research

Temperature has a causal and plastic effect on timing of breeding in a small songbird [RESEARCH ARTICLE]
Irene Verhagen, Barbara M Tomotani, Phillip Gienapp, and Marcel E Visser Phenotypic plasticity is an important mechanism by which an individual can adapt its seasonal timing to predictable, short-term environmental changes by using predictive cues. Identification of these cues is crucial to forecast species’ response to long-term environmental change and to study their potential to adapt. Individual great tits (Parus major) start reproduction early under warmer conditions in the wild, but whether this effect is causal is not well known. We housed 36 pairs in climate-controlled aviaries and 40 pairs in outdoor aviarie...
Source: Journal of Experimental Biology - March 23, 2020 Category: Biology Authors: Verhagen, I., Tomotani, B. M., Gienapp, P., Visser, M. E. Tags: RESEARCH ARTICLE Source Type: research

Habituation of the cardiovascular responses to restraint stress is inhibited by exposure to other stressor stimuli and exercise training [RESEARCH ARTICLE]
This study evaluated the effect of exposure to either a chronic variable stress (CVS) protocol or social isolation, as well as to treadmill exercise training, in the habituation of the cardiovascular responses upon repeated exposure to restraint stress in rats. The habituation of the corticosterone response to repeated restraint stress was also evaluated. For this, animals were subjected to either acute or 10 daily sessions of 60 min of restraint stress. CVS and social isolation protocols lasted 10 consecutive days, whereas treadmill training was performed 1h/day, 5 days/week for 8 weeks. We observed that serum corticoster...
Source: Journal of Experimental Biology - March 23, 2020 Category: Biology Authors: Benini, R., Oliveira, L. A., Gomes-de-Souza, L., Rodrigues, B., Crestani, C. C. Tags: RESEARCH ARTICLE Source Type: research

Consequences of rapid development owing to cohort splitting: just how costly is it to hurry? [RESEARCH ARTICLE]
Zoltan Radai, Johanna Kiss, Agnieszka Babczynska, Gabor Kardos, Ferenc Bathori, Ferenc Samu, and Zoltan Barta In cohort splitting, diverging sub-cohorts may show substantial differences in their growth and developmental rates. Although in the past, causes and adaptive value of cohort splitting were studied in detail, individual-level consequences of cohort splitting are still rather overlooked. Life history theory predicts that considerably increased growth and developmental rates should be traded off against other costly life history traits. However, it is not clear whether one should expect such associations in adaptive...
Source: Journal of Experimental Biology - March 20, 2020 Category: Biology Authors: Radai, Z., Kiss, J., Babczynska, A., Kardos, G., Bathori, F., Samu, F., Barta, Z. 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]
Guy A. M. Messa, Mathew Piasecki, Josh Hurst, Cameron Hill, Jason Tallis, and Hans Degens Prolonged high-fat diets (HFDs) can cause intramyocellular lipid (IMCL) accumulation that may negatively affect muscle function. We investigated the duration of a HFD required to instigate these changes, and whether the effects are muscle specific and aggravated in older age. Muscle morphology was determined in the soleus, extensor digitorum longus (EDL) and diaphragm muscles of female CD-1 mice from 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...
Source: Journal of Experimental Biology - March 20, 2020 Category: Biology Authors: Messa, G. A. M., Piasecki, M., Hurst, J., Hill, C., Tallis, J., Degens, H. Tags: RESEARCH ARTICLE Source Type: research

Fat loss triggers ant lifestyle change [INSIDE JEB]
Kathryn Knight (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - March 19, 2020 Category: Biology Authors: Knight, K. Tags: INSIDE JEB Source Type: research

Lipid content influences division of labour in a clonal ant [RESEARCH ARTICLE]
In this study, we examined the range of variation and flexibility of fat content throughout the lifespan of workers, the threshold of corpulence associated with foraging or reproduction and whether low fat content is a cause rather than a consequence of the transition to foraging. We found that lipid stores change with division of labour from corpulent to lean and, in reverted nurses, back to corpulent. In addition, our data show the presence of fat content thresholds that trigger the onset of foraging or egg-laying behaviour. Our study supports the view that mechanisms that regulate reproduction and foraging in solitary i...
Source: Journal of Experimental Biology - March 19, 2020 Category: Biology Authors: Bernadou, A., Hoffacker, E., Pable, J., Heinze, J. Tags: RESEARCH ARTICLE Source Type: research

Rapid adaptive evolution of scale-eating kinematics to a novel ecological niche [RESEARCH ARTICLE]
Michelle E. St. John, Roi Holzman, and Christopher H. Martin The origins of novel trophic specialization, in which organisms begin to exploit resources for the first time, may be explained by shifts in behavior such as foraging preferences or feeding kinematics. One way to investigate behavioral mechanisms underlying ecological novelty is by comparing prey capture kinematics among species. We investigated the contribution of kinematics to the origins of a novel ecological niche for scale-eating within a microendemic adaptive radiation of pupfishes on San Salvador Island, Bahamas. We compared prey capture kinematics across...
Source: Journal of Experimental Biology - March 19, 2020 Category: Biology Authors: St. John, M. E., Holzman, R., Martin, C. H. Tags: RESEARCH ARTICLE Source Type: research

Evaluation of laser scanning confocal microscopy as a method for characterizing reef-building coral tissue thickness and Symbiodiniaceae fluorescence [METHODS [amp ] TECHNIQUES]
A. S. Huffmyer, S. B. Matsuda, A. R. Eggers, J. D. Lemus, and R. D. Gates Predicting the sensitivity of reef-building corals to disturbance, including bleaching, requires an understanding of physiological responses to stressors, which may be limited by destructive sampling and the capacity of common methodologies to characterize early life history stages. We developed a new methodology using laser scanning confocal microscopy (LSCM) to measure and track the physiological condition of corals. In a thermal stress experiment, we used LSCM to track coral condition during bleaching in adults and juveniles of two species, Monti...
Source: Journal of Experimental Biology - March 18, 2020 Category: Biology Authors: Huffmyer, A. S., Matsuda, S. B., Eggers, A. R., Lemus, J. D., Gates, R. D. Tags: METHODS [amp ] TECHNIQUES Source Type: research

Swimming in unsteady water flows: is turning in a changing flow an energetically expensive endeavor for fish? [RESEARCH ARTICLE]
In this study, we used a bidirectional swimming respirometer to create six oscillatory water flow regimes consisting of three frequency and amplitude combinations for both unidirectional and bidirectional oscillatory flows. Using the goldring surgeonfish, Ctenochaetus strigosus, a pectoral-fin (labriform) swimmer, we quantified the net cost of swimming (swimming metabolic rate minus standard metabolic rate) associated with station-holding under these various conditions. We determined that the swimming costs of station-holding in the bidirectional flow regime increased by 2-fold compared with costs based on swimming over th...
Source: Journal of Experimental Biology - March 18, 2020 Category: Biology Authors: Schakmann, M., Steffensen, J. F., Bushnell, P. G., Korsmeyer, K. E. Tags: RESEARCH ARTICLE Source Type: research

Amphibious hearing in a diving bird, the great cormorant (Phalacrocorax carbo sinensis) [RESEARCH ARTICLE]
Ole Naesbye Larsen, Magnus Wahlberg, and Jakob Christensen-Dalsgaard Diving birds can spend several minutes underwater during pursuit-dive foraging. To find and capture prey, such as fish and squid, they probably need several senses in addition to vision. Cormorants, very efficient predators of fish, have unexpectedly low visual acuity underwater. So, underwater hearing may be an important sense, as for other diving animals. We measured auditory thresholds and eardrum vibrations in air and underwater of the great cormorant (Phalacrocorax carbo sinensis). Wild-caught cormorant fledglings were anaesthetized, and their audit...
Source: Journal of Experimental Biology - March 17, 2020 Category: Biology Authors: Larsen, O. N., Wahlberg, M., Christensen-Dalsgaard, J. Tags: RESEARCH ARTICLE Source Type: research

Divergent neurogenomic responses shape social learning of both personality and mate preference [RESEARCH ARTICLE]
In this study on swordtail fish (Xiphophorus birchmanni), we show that female mating preferences for species-typical pheromone cues are entirely dependent on social experience with adult males. Experience with adults also shapes development along the shy–bold personality axis, with shy behaviors arising from exposure to risk-averse heterospecifics as a potential stress-coping strategy. In maturing females, conspecific exposure results in a strong upregulation of olfaction and vision genes compared with heterospecific exposure, as well as immune response genes previously linked to anxiety, learning and memory. Convers...
Source: Journal of Experimental Biology - March 16, 2020 Category: Biology Authors: Delclos, P. J., Forero, S. A., Rosenthal, G. G. Tags: RESEARCH ARTICLE Source Type: research

Low-dose immune challenges result in detectable levels of oxidative damage [RESEARCH ARTICLE]
Ellen M. Armour, Taylor L. Bruner, Justin K. Hines, and Michael W. Butler Infection can result in substantial costs to animals, so they frequently respond by removing infectious agents with an immune response. However, immune responses entail their own costs, including upregulation of processes that destroy pathogens (e.g. the production of reactive oxygen species) and processes that limit the extent of self-damage during the immune response (e.g. production of anti-inflammatory proteins such as haptoglobin). Here, we simulated bacterial infection across a 1000-fold range using lipopolysaccharide (LPS) administered to nor...
Source: Journal of Experimental Biology - March 16, 2020 Category: Biology Authors: Armour, E. M., Bruner, T. L., Hines, J. K., Butler, M. W. Tags: RESEARCH ARTICLE Source Type: research

Age-dependent release of and response to alarm pheromone in a ponerine ant [RESEARCH ARTICLE]
Tamara Pokorny, Lisa-Marie Sieber, John E. Hofferberth, Abel Bernadou, and Joachim Ruther Social insect societies are characterized by division of labour and communication within the colony. The most frequent mode of communication is by chemical signals. In general, pheromones elicit specific responses in the receiver, although reactions may vary depending on the receiving individual's physiological or motivational state. For example, it has been shown that pheromones can elicit different responses in morphological worker castes. However, comparably little is known about such effects in worker castes of monomorphic specie...
Source: Journal of Experimental Biology - March 16, 2020 Category: Biology Authors: Pokorny, T., Sieber, L.-M., Hofferberth, J. E., Bernadou, A., Ruther, J. Tags: RESEARCH ARTICLE Source Type: research

Developmental changes in bone mechanics from Florida manatees (Trichechus manatus latirostris), obligate swimming mammals [RESEARCH ARTICLE]
Danielle N. Ingle and Marianne E. Porter Mammals living in aquatic environments load their axial skeletons differently from their terrestrial counterparts. The structure and mechanical behavior of trabecular bone can be especially indicative of varying habitual forces. Here, we investigated vertebral trabecular bone mechanical properties (yield strength, stiffness and toughness) throughout development in Florida manatees (Trichechus manatus latirostris), obligate undulatory swimmers. Thoracic, lumbar and caudal vertebrae were dissected from manatees (N=20) during necropsies. We extracted 6 mm3 samples from vertebral ...
Source: Journal of Experimental Biology - March 16, 2020 Category: Biology Authors: Ingle, D. N., Porter, M. E. Tags: RESEARCH ARTICLE Source Type: research

The effect of vertical extent of stimuli on cockroach optomotor response [RESEARCH ARTICLE]
Juha Nuutila, Anna E. Honkanen, Kyösti Heimonen, and Matti Weckström Using tethered American cockroaches walking on a trackball in a spherical virtual reality environment, we tested optomotor responses to horizontally moving black-and-white gratings of different vertical extent under six different light intensities. We found that shortening the vertical extent of the wide-field stimulus grating within a light level weakened response strength, reduced average velocity, and decreased angular walking distance. Optomotor responses with the vertically shortened stimuli persisted down to light intensity levels of 0.05 lx. Re...
Source: Journal of Experimental Biology - March 16, 2020 Category: Biology Authors: Nuutila, J., Honkanen, A. E., Heimonen, K., Weckström, M. Tags: RESEARCH ARTICLE Source Type: research

In vitro insulin treatment reverses changes elicited by nutrients in cellular metabolic processes that regulate food intake in fish [RESEARCH ARTICLE]
This study adds new information on our knowledge of the mechanisms regulating nutrient sensing in fish. (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - March 16, 2020 Category: Biology Authors: Blanco, A. M., Bertucci, J. I., Soengas, J. L., Unniappan, S. Tags: RESEARCH ARTICLE Source Type: research

Emergent properties of branching morphologies modulate the sensitivity of coral calcification to high PCO2 [RESEARCH ARTICLE]
Peter J. Edmunds and Scott C. Burgess Experiments with coral fragments (i.e., nubbins) have shown that net calcification is depressed by elevated PCO2. Evaluating the implications of this finding requires scaling of results from nubbins to colonies, yet the experiments to codify this process have not been completed. Building from our previous research demonstrating that net calcification of Pocillopora verrucosa (2–13 cm diameter) was unaffected by PCO2 (400 µtam and 1,000 µatm) and temperature (26.5°C and 29.7°C) we sought generality to this outcome by testing how colony size modulates PCO2 and t...
Source: Journal of Experimental Biology - March 16, 2020 Category: Biology Authors: Edmunds, P. J., Burgess, S. C. Tags: RESEARCH ARTICLE Source Type: research

Experimental facilitation of heat loss affects work rate and innate immune function in a breeding passerine bird [RESEARCH ARTICLE]
Fredrik Andreasson, Arne Hegemann, Andreas Nord, and Jan-Ake Nilsson The capacity to get rid of excess heat produced during hard work is a possible constraint on parental effort during reproduction (heat dissipation limit [HDL] theory). We released hard-working blue tits (Cyanistes caeruleus) from this constraint by experimentally removing ventral plumage. We then assessed if this changed their reproductive effort (feeding rate and nestling size) and levels of self-maintenance (change in body mass and innate immune function). Feather-clipped females reduced the number of feeding visits and increased levels of constitutive ...
Source: Journal of Experimental Biology - March 16, 2020 Category: Biology Authors: Andreasson, F., Hegemann, A., Nord, A., Nilsson, J.-A. Tags: RESEARCH ARTICLE Source Type: research

Assessing intracellular pH regulation in H+-ATPase-rich ionocytes in zebrafish larvae using in vivo ratiometric imaging [RESEARCH ARTICLE]
H. M. Yew, A. M. Zimmer, and S. F. Perry The H+-ATPase-rich (HR) cells of zebrafish larvae are a sub-type of ion-transporting cell located on the yolk sac epithelium that are responsible for Na+ uptake and H+ extrusion. Current models of HR cell ion transport mechanisms in zebrafish larvae are well established, but little is known about the involvement of the various ion transport pathways in regulating intracellular acid–base status. Here, a ratiometric imaging technique was developed and validated to monitor intracellular pH (pHi) continuously in larval zebrafish HR cells in vivo. Gene knockdown or CRISPR/Cas9 kno...
Source: Journal of Experimental Biology - March 12, 2020 Category: Biology Authors: Yew, H. M., Zimmer, A. M., Perry, S. F. Tags: RESEARCH ARTICLE Source Type: research

The startle reflex in echolocating odontocetes: basic physiology and practical implications [RESEARCH ARTICLE]
Thomas Götz, Aude F. Pacini, Paul E. Nachtigall, and Vincent M. Janik The acoustic startle reflex is an oligo-synaptic reflex arc elicited by rapid-onset sounds. Odontocetes evolved a range of specific auditory adaptations to aquatic hearing and echolocation, e.g. the ability to downregulate their auditory sensitivity when emitting clicks. However, it remains unclear whether these adaptations also led to changes of the startle reflex. We investigated reactions to startling sounds in two bottlenose dolphins (Tursiops truncatus) and one false killer whale (Pseudorca crassidens). Animals were exposed to 50 ms, 1/3 oct...
Source: Journal of Experimental Biology - March 12, 2020 Category: Biology Authors: Götz, T., Pacini, A. F., Nachtigall, P. E., Janik, V. M. Tags: RESEARCH ARTICLE Source Type: research

Compensatory changes in villus morphology of lactating Mus musculus in response to insufficient dietary protein [SHORT COMMUNICATION]
We examined how intestinal size responds to insufficient dietary protein at the microscopic level. Villi, enterocytes, and surface area were measured across the length of the small intestine in non-reproductive and lactating Mus musculus fed isocaloric control or protein-deficient diets. Lactating mice on the protein-deficient diet exhibited a 24% increase in villus height and a 30% increase in enterocyte width in the proximal small intestine and an overall similar increase in surface area; on the control diet changes in villus height were localized in the mid region. Flexibility localized to the proximal small intestine s...
Source: Journal of Experimental Biology - March 12, 2020 Category: Biology Authors: Short, K., Derrickson, E. M. Tags: SHORT COMMUNICATION Source Type: research

Variation in outer blubber lipid concentrations does not reflect morphological body condition in humpback whales [RESEARCH ARTICLE]
Fredrik Christiansen, Kate R. Sprogis, Jasmin Gross, Juliana Castrillon, Hunter A. Warick, Eva Leunissen, and Susan Bengtson Nash An animal's body condition provides valuable information for ecophysiological studies, and is an important measure of fitness in population monitoring and conservation. While both the external body shape of an animal, as well as its internal tissues (i.e. fat content) can be used as measures of body condition, the relationship between the two is not always linear. We compared the morphological body condition (external metric obtained through aerial photogrammetry) of migrating humpback whales (M...
Source: Journal of Experimental Biology - March 12, 2020 Category: Biology Authors: Christiansen, F., Sprogis, K. R., Gross, J., Castrillon, J., Warick, H. A., Leunissen, E., Bengtson Nash, S. Tags: RESEARCH ARTICLE Source Type: research

Food restriction delays seasonal sexual maturation but does not increase torpor use in male bats [RESEARCH ARTICLE]
Ewa Komar, Dina K. N. Dechmann, Nicolas J. Fasel, Marcin Zegarek, and Ireneusz Ruczynski Balancing energy budgets can be challenging, especially in periods of food shortage, adverse weather conditions and increased energy demand due to reproduction. Bats have particularly high energy demands compared to other mammals and regularly use torpor to save energy. However, while torpor limits energy expenditure, it can also downregulate important processes, such as sperm production. This constraint could result in a trade-off between energy saving and future reproductive capacity. We mimicked harsh conditions by restricting food ...
Source: Journal of Experimental Biology - March 12, 2020 Category: Biology Authors: Komar, E., Dechmann, D. K. N., Fasel, N. J., Zegarek, M., Ruczynski, I. Tags: RESEARCH ARTICLE Source Type: research

Skeletal muscle thermogenesis induction by exposure to predator odor [RESEARCH ARTICLE]
In this study, we identify a contextual stimulus that induces rapid and robust thermogenesis in skeletal muscle. Rats exposed to the odor of a natural predator (ferret odor) show elevated skeletal muscle temperatures detectable as quickly as 2 min after exposure, reaching maximum thermogenesis of>1.5 °C at 10-15 min. Mice exhibit a similar thermogenic response to the same odor. Ferret odor induces a significantly larger and qualitatively different response than do novel or aversive odors, fox odor, or moderate restraint stress. Exposure to predator odor increases energy expenditure, and both the thermogenic and ener...
Source: Journal of Experimental Biology - March 12, 2020 Category: Biology Authors: Gorrell, E., Shemery, A., Kowalski, J., Bodziony, M., Mavundza, N., Titus, A. R., Yoder, M., Mull, S., Heemstra, L. A., Wagner, J. G., Gibson, M., Carey, O., Daniel, D., Harvey, N., Zendlo, M., Rich, M., Everett, S., Gavini, C. K., Almundarij, T. I., Lort Tags: RESEARCH ARTICLE Source Type: research

Consequences of being phenotypically mismatched with the environment: no evidence of oxidative stress in cold and warm acclimated birds facing a cold spell [RESEARCH ARTICLE]
Ana Gabriela Jimenez, Emily Cornelius Ruhs, Kailey J. Tobin, Katie N. Anderson, Audrey Le Pogam, Lyette Regimbald, and Francois Vezina Seasonal changes in maximal thermogenic capacity (Msum) in wild black-capped chickadees suggests that adjustments in metabolic performance are slow and begin to take place before winter peaks. However, when mean minimal ambient temperature (Ta) reaches -10°C, chickadee's phenotype appears to provide enough spare capacity to endure days with colder Tas, down to -20°C or below. This suggests that birds could also maintain a higher antioxidant capacity as part of their cold acclimated ...
Source: Journal of Experimental Biology - March 12, 2020 Category: Biology Authors: Jimenez, A. G., Cornelius Ruhs, E., Tobin, K. J., Anderson, K. N., Le Pogam, A., Regimbald, L., Vezina, F. Tags: RESEARCH ARTICLE Source Type: research

Phenotypic flexibility of metabolic rate and evaporative water loss does not vary across a climatic gradient in an Afrotropical passerine bird [RESEARCH ARTICLE]
Matthew J. Noakes and Andrew E. McKechnie Small birds inhabiting northern temperate and boreal latitudes typically increase metabolic rates during cold winters or acclimation to low air temperatures (Taccl). Recent studies suggest considerable variation in patterns of seasonal metabolic acclimatization in birds from subtropical and tropical regions with milder winters, but there remains a dearth of acclimation studies investigating metabolic flexibility among lower-latitude birds. We used short-term thermal acclimation experiments to investigate phenotypic flexibility in basal metabolic rate (BMR), thermoneutral evaporativ...
Source: Journal of Experimental Biology - March 12, 2020 Category: Biology Authors: Noakes, M. J., McKechnie, A. E. Tags: RESEARCH ARTICLE Source Type: research

Microclimate buffering and thermal tolerance across elevations in a tropical butterfly [RESEARCH ARTICLE]
Gabriela Montejo-Kovacevich, Simon H. Martin, Joana I. Meier, Caroline N. Bacquet, Monica Monllor, Chris D. Jiggins, and Nicola J. Nadeau Microclimatic variability in tropical forests plays a key role in shaping species distributions and their ability to cope with environmental change, especially for ectotherms. Nonetheless, currently available climatic datasets lack data from the forest interior and, furthermore, our knowledge of thermal tolerance among tropical ectotherms is limited. We therefore studied natural variation in the microclimate experienced by tropical butterflies in the genus Heliconius across their Andean ...
Source: Journal of Experimental Biology - March 12, 2020 Category: Biology Authors: Montejo-Kovacevich, G., Martin, S. H., Meier, J. I., Bacquet, C. N., Monllor, M., Jiggins, C. D., Nadeau, N. J. Tags: RESEARCH ARTICLE Source Type: research

The glue produced by Drosophila melanogaster for pupa adhesion is universal [RESEARCH ARTICLE]
Flora Borne, Alexander Kovalev, Stanislav Gorb, and Virginie Courtier-Orgogozo Insects produce a variety of adhesives for diverse functions such as locomotion, mating, egg or pupal anchorage to substrates. Although they are important for the biology of organisms and potentially represent a great resource for developing new materials, insect adhesives have been little studied so far. Here, we examined the adhesive properties of the larval glue of Drosophila melanogaster. This glue is made of glycosylated proteins and allows the animal to adhere to a substrate during metamorphosis. We designed an adhesion test to measure the...
Source: Journal of Experimental Biology - March 12, 2020 Category: Biology Authors: Borne, F., Kovalev, A., Gorb, S., Courtier-Orgogozo, V. Tags: RESEARCH ARTICLE Source Type: research

African pygmy mouse upgrades mitochondria to compensate for size [INSIDE JEB]
Kathryn Knight (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - March 11, 2020 Category: Biology Authors: Knight, K. Tags: INSIDE JEB Source Type: research

Ontogenesis of evolved changes in respiratory physiology in deer mice native to high altitude [RESEARCH ARTICLE]
We examined the developmental changes in respiratory and haematological traits in deer mice (Peromyscus maniculatus) native to high altitude, comparing the respiratory responses to progressive hypoxia between highland and lowland deer mice. Among adults, highlanders exhibited higher total ventilation and a more effective breathing pattern (relatively deeper tidal volumes), for mice that were caught and tested at their native altitudes and those lab-raised in normoxia. Lab-raised progeny of each population were also tested at post-natal day (P)7, 14, 21 and 30. Highlanders developed an enhanced hypoxic ventilatory response ...
Source: Journal of Experimental Biology - March 11, 2020 Category: Biology Authors: Ivy, C. M., Greaves, M. A., Sangster, E. D., Robertson, C. E., Natarajan, C., Storz, J. F., McClelland, G. B., Scott, G. R. Tags: RESEARCH ARTICLE Source Type: research

Choice consequences: salinity preferences and hatchling survival in the mangrove rivulus (Kryptolebias marmoratus) [RESEARCH ARTICLE]
We examined the salinity preference of mangrove rivulus in a lateral salinity gradient, in the absence of predators and competitors. Fish could swim freely for 8 h throughout the gradient with chambers containing salinities ranging from 5 to 45 ppt (or 25 ppt throughout in the control). We defined preference as the salinity in which the fish spent most of their time, and also measured preference strength, latency to begin exploring the arena, and number of transitions between chambers. To determine whether these traits were repeatable, each fish experienced three trials. Mangrove rivulus spent a greater prop...
Source: Journal of Experimental Biology - March 11, 2020 Category: Biology Authors: McCain, S. C., Kopelic, S., Houslay, T. M., Wilson, A. J., Lu, H., Earley, R. L. Tags: RESEARCH ARTICLE Source Type: research

Hypoxia tolerance is unrelated to swimming metabolism of wild, juvenile striped bass (Morone saxatilis) [RESEARCH ARTICLE]
Krista Kraskura and Jay A. Nelson Juvenile striped bass residing in Chesapeake Bay are likely to encounter hypoxia that could affect their metabolism and performance. The ecological success of this economically valuable species may depend on their ability to tolerate hypoxia and perform fitness-dependent activities in hypoxic waters. We tested whether there is a link between hypoxia tolerance (HT) and oxygen consumption rate (MO2) of juvenile striped bass measured while swimming in normoxic and hypoxic water, and to identify the interindividual variation and repeatability of these measurements. HT (loss of equilibrium) of...
Source: Journal of Experimental Biology - March 11, 2020 Category: Biology Authors: Kraskura, K., Nelson, J. A. Tags: RESEARCH ARTICLE Source Type: research

Improved mitochondrial coupling as a response to high mass-specific metabolic rate in extremely small mammals [RESEARCH ARTICLE]
Melanie Boël, Caroline Romestaing, Claude Duchamp, Frederic Veyrunes, Sabrina Renaud, Damien Roussel, and Yann Voituron Mass-specific metabolic rate negatively co-varies with body mass from the whole-animal to the mitochondrial levels. Mitochondria are the mainly consumers of oxygen inspired by mammals to generate ATP or compensate for energetic losses dissipated as the form of heat (proton leak) during oxidative phosphorylation. Consequently, ATP synthesis and proton leak compete for the same electrochemical gradient. Because proton leak co-varies negatively with body mass, it is unknown whether extremely small mammals...
Source: Journal of Experimental Biology - March 11, 2020 Category: Biology Authors: Boël, M., Romestaing, C., Duchamp, C., Veyrunes, F., Renaud, S., Roussel, D., Voituron, Y. Tags: RESEARCH ARTICLE Source Type: research

Stroke effort and relative lung volume influence heart rate in diving sea lions [RESEARCH ARTICLE]
This study assessed the potential role of exercise and relative lung volume in the regulation of heart rate (fH) during dives of adult female California sea lions instrumented with electrocardiogram (ECG), depth and tri-axial acceleration data loggers. A positive relationship between activity (minimum specific acceleration) and fH throughout dives suggested increased muscle perfusion associated with exercise. However, apart from late ascent, fH during dives was still less than or equal to resting fH (on land). In addition, the activity–fH relationship was weaker in long, deep dives consistent with prioritization of b...
Source: Journal of Experimental Biology - March 11, 2020 Category: Biology Authors: McDonald, B. I., Tift, M. S., Hückstädt, L. A., Jeffko, M., Ponganis, P. J. Tags: RESEARCH ARTICLE Source Type: research

Connecting brain to behaviour: a role for general purpose steering circuits in insect orientation? [COMMENTARY]
Fabian Steinbeck, Andrea Adden, and Paul Graham The lateral accessory lobes (LALs), paired structures that are homologous among all insect species, have been well studied for their role in pheromone tracking in silkmoths and phonotaxis in crickets, where their outputs have been shown to correlate with observed motor activity. Further studies have shown more generally that the LALs are crucial both for an insect's ability to steer correctly and for organising the outputs of the descending pathways towards the motor centres. In this context, we propose a framework by which the LALs may be generally involved in generating st...
Source: Journal of Experimental Biology - March 11, 2020 Category: Biology Authors: Steinbeck, F., Adden, A., Graham, P. Tags: Neuroethology COMMENTARY Source Type: research

Cardiovascular responses to progressive hypoxia in ducks native to high altitude in the Andes [RESEARCH ARTICLE]
Sabine L. Laguë, Catherine M. Ivy, Julia M. York, Beverly A. Chua, Luis Alza, Rebecca Cheek, Neal J. Dawson, Peter B. Frappell, Anthony P. Farrell, Kevin G. McCracken, Graham R. Scott, and William K. Milsom The cardiovascular system is critical for delivering O2 to tissues. Here, we examined the cardiovascular responses to progressive hypoxia in four high-altitude Andean duck species compared with four related low-altitude populations in North America, tested at their native altitude. Ducks were exposed to stepwise decreases in inspired partial pressure of O2 while we monitored heart rate, O2 consumption rate, blood O2 ...
Source: Journal of Experimental Biology - March 11, 2020 Category: Biology Authors: Laguë, S. L., Ivy, C. M., York, J. M., Chua, B. A., Alza, L., Cheek, R., Dawson, N. J., Frappell, P. B., Farrell, A. P., McCracken, K. G., Scott, G. R., Milsom, W. K. Tags: RESEARCH ARTICLE Source Type: research

Ringtail possums let their temperature rise to save water when Australia gets hot [INSIDE JEB]
Kathryn Knight (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - March 6, 2020 Category: Biology Authors: Knight, K. Tags: INSIDE JEB 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 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 (3D) 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 simple vertical jaw move...
Source: Journal of Experimental Biology - March 6, 2020 Category: Biology Authors: Schwarz, D., Konow, N., Roba, Y. T., Heiss, E. Tags: RESEARCH ARTICLE Source Type: research

Facultative hyperthermia during a heatwave delays injurious dehydration of an arboreal marsupial [SHORT COMMUNICATION]
James M. Turner Heatwaves negatively impact wildlife populations and their effects are predicted to worsen with ongoing global warming. Animal mass mortality at extremely high ambient temperature (Ta) is evidence for physiological dysfunction and, to aid conservation efforts, improving our understanding of animal responses to environmental heat is crucial. To address this, I measured the water loss, body temperature and metabolism of an Australian marsupial during a simulated heatwave. The body temperature of the common ringtail possum Pseudocheirus peregrinus increased passively by ~3°C over a Ta of 29–39°C...
Source: Journal of Experimental Biology - March 6, 2020 Category: Biology Authors: Turner, J. M. Tags: Ecophysiology: responses to environmental stressors and change SHORT COMMUNICATION Source Type: research