Jaw kinematics and tongue protraction-retraction during Chewing and drinking in the pig [RESEARCH ARTICLE]
The objective of this study is to compare jaw and tongue kinematics during chewing and drinking in pigs. We hypothesize there will be differences in jaw gape cycle dynamics and tongue protraction-retraction between behaviors. Mastication cycles had an extended slow-close phase, reflecting tooth-food-tooth contact, whereas drinking cycles had an extended slow-open phase, corresponding to tongue protrusion into the liquid. Compared to chewing, drinking jaw movements were of lower magnitude for all degrees of freedom examined (jaw protraction, yaw, and pitch), and were bilaterally symmetrical with virtually no yaw. The magnit...
Source: Journal of Experimental Biology - March 5, 2021 Category: Biology Authors: Olson, R. A., Montuelle, S. J., Chadwell, B. A., Curtis, H., Williams, S. H. Tags: RESEARCH ARTICLE Source Type: research

Na+/H+-exchangers differentially contribute to midgut fluid sodium and proton concentration in the sea urchin larva [RESEARCH ARTICLE]
Inga Petersen, William W. J. Chang, and Marian Y. Hu Regulation of ionic composition and pH is a requisite of all digestive systems in the animal kingdom. Larval stages of the marine superphylum ambulacraria, including echinoderms and hemichordates, were demonstrated to have highly alkaline conditions in their midgut with the underlying epithelial transport mechanisms being largely unknown.Using ion-selective microelectrodes, the present study demonstrated that pluteus larvae of the purple sea urchin have highly alkaline pH (pH ~9) and low [Na+] ( 120 mM) in their midgut fluids, compared to the ionic composition of the sur...
Source: Journal of Experimental Biology - March 5, 2021 Category: Biology Authors: Petersen, I., Chang, W. W. J., Hu, M. Y. Tags: RESEARCH ARTICLE Source Type: research

Testing the influence of crushing surface variation on seed-cracking performance among beak morphs of the African seedcracker Pyrenestes ostrinus [RESEARCH ARTICLE]
Nicola S. Heckeberg, Philip S. L. Anderson, and Emily J. Rayfield Extreme phenotypic polymorphism is an oft-cited example of evolutionary theory in practice. Although these morphological variations are assumed to be adaptive, few studies have biomechanically tested such hypotheses. Pyrenestes ostrinus (the African seedcracker finch) shows an intraspecific polymorphism in beak size and shape that is entirely diet driven and allelically determined. Three distinct morphs feed upon soft sedge seeds during times of abundance, but during lean times switch to specializing on three different species of sedge seeds that differ sig...
Source: Journal of Experimental Biology - March 4, 2021 Category: Biology Authors: Heckeberg, N. S., Anderson, P. S. L., Rayfield, E. J. Tags: RESEARCH ARTICLE Source Type: research

Social organisation and the evolution of life-history traits in two queen morphs of the ant Temnothorax rugatulus [RESEARCH ARTICLE]
Matteo A. Negroni, Marah Stoldt, Marie Oster, Ann-Sophie Rupp, Barbara Feldmeyer, and Susanne Foitzik During social evolution, life-history traits not only diverged, with social insect queens becoming highly fecund and long-lived compared to their sterile workers, but also individual traits lost their importance compared to colony-level traits. In solitary animals, fecundity is largely influenced by female size, whereas in eusocial insects, colony size and queen number can affect the egg-laying rate. Here we focussed on the ant Temnothorax rugatulus, which exhibits two queen morphs varying in size and reproductive strategy...
Source: Journal of Experimental Biology - March 3, 2021 Category: Biology Authors: Negroni, M. A., Stoldt, M., Oster, M., Rupp, A.-S., Feldmeyer, B., Foitzik, S. Tags: RESEARCH ARTICLE Source Type: research

Independent effects of seawater pH and high PCO2 on olfactory sensitivity in fish: possible role of carbonic anhydrase [RESEARCH ARTICLE]
Zelia Velez, Rita A. Costa, Wenjing Wang, and Peter C. Hubbard Ocean acidification may alter olfactory-driven behaviour in fish by direct effects on the peripheral olfactory system; olfactory sensitivity is reduced in CO2-acidified seawater. The current study tested whether this is due to elevated PCO2 or the consequent reduction in seawater pH and, if the former, investigate the possible involvement of carbonic anhydrase, the enzyme responsible for the hydration of CO2 and production of carbonic acid. Olfactory sensitivity to amino acids was assessed by extracellular multi-unit recording from the olfactory nerve of the gi...
Source: Journal of Experimental Biology - March 3, 2021 Category: Biology Authors: Velez, Z., Costa, R. A., Wang, W., Hubbard, P. C. Tags: RESEARCH ARTICLE Source Type: research

Diversity in rest-activity patterns among Lake Malawi cichlid fishes suggests a novel axis of habitat partitioning [RESEARCH ARTICLE]
Evan Lloyd, Brian Chhouk, Andrew J. Conith, Alex C. Keene, and R. Craig Albertson Animals display remarkable diversity in rest and activity patterns that are regulated by endogenous foraging strategies, social behaviors, and predator avoidance. Alteration in the circadian timing of activity or the duration of rest-wake cycles provide a central mechanism for animals to exploit novel niches. The diversity of the 3000+ cichlid species throughout the world provides a unique opportunity to examine variation in locomotor activity and rest. Lake Malawi alone is home to over 500 species of cichlids that display divergent behaviors...
Source: Journal of Experimental Biology - March 3, 2021 Category: Biology Authors: Lloyd, E., Chhouk, B., Conith, A. J., Keene, A. C., Albertson, R. C. Tags: RESEARCH ARTICLE Source Type: research

Novice gyrfalcons cut straight to the kill on maiden flight [INSIDE JEB]
Kathryn Knight (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - March 2, 2021 Category: Biology Authors: Knight, K. Tags: INSIDE JEB Source Type: research

Attack behaviour in naive gyrfalcons is modelled by the same guidance law as in peregrine falcons, but at a lower guidance gain [RESEARCH ARTICLE]
Caroline H. Brighton, Katherine E. Chapman, Nicholas C. Fox, and Graham K. Taylor The aerial hunting behaviours of birds are strongly influenced by flight morphology and ecology, but little is known of how this relates to the behavioural algorithms guiding flight. Here, we used GPS loggers to record the attack trajectories of captive-bred gyrfalcons (Falco rusticolus) during their maiden flights against robotic aerial targets, which we compared with existing flight data from peregrine falcons (Falco peregrinus). The attack trajectories of both species were well modelled by a proportional navigation (PN) guidance law, whic...
Source: Journal of Experimental Biology - March 2, 2021 Category: Biology Authors: Brighton, C. H., Chapman, K. E., Fox, N. C., Taylor, G. K. Tags: Comparative biomechanics of movement RESEARCH ARTICLE Source Type: research

Size, shape, and orientation of macro-sized substrate protrusions affect the toe and foot adhesion of geckos [RESEARCH ARTICLE]
Yi Song, Jiwei Yuan, Linghao Zhang, Zhendong Dai, and Robert J. Full Geckos are excellent climbers using compliant, hierarchically-arranged adhesive toes to negotiate diverse terrains varying in roughness at multiple size scales. Here, we complement advancements at smaller size scales with measurements at the macro-scale. We studied the attachment of a single toe and whole foot of geckos on macro-scale rough substrates by pulling them along, across, and off smooth rods and spheres mimicking different geometric protrusions of substrates. When we pulled a single toe along rods, the force increased with the rod diameter. Wher...
Source: Journal of Experimental Biology - March 2, 2021 Category: Biology Authors: Song, Y., Yuan, J., Zhang, L., Dai, Z., Full, R. J. Tags: RESEARCH ARTICLE Source Type: research

Attention and distraction in the modular visual system of a jumping spider [SHORT COMMUNICATION]
Margaret Bruce, Daniel Daye, Skye M. Long, Alex M. Winsor, Gil Menda, Ronald R. Hoy, and Elizabeth M. Jakob Animals must selectively attend to relevant stimuli and avoid being distracted by unimportant stimuli. Jumping spiders (Salticidae) do this by coordinating eyes with different capabilities. Objects are examined by a pair of high-acuity principal eyes, whose narrow field of view is compensated for by retinal movements. The principal eyes overlap in field of view with motion-sensitive anterior-lateral eyes, which direct their gaze to new stimuli. Using a salticid-specific eyetracker, we monitored the gaze direction of ...
Source: Journal of Experimental Biology - March 2, 2021 Category: Biology Authors: Bruce, M., Daye, D., Long, S. M., Winsor, A. M., Menda, G., Hoy, R. R., Jakob, E. M. Tags: SHORT COMMUNICATION Source Type: research

Social Immunity in Honey Bees: Royal Jelly as a Vehicle in Transferring Bacterial Pathogen Fragments Between Nestmates [RESEARCH ARTICLE]
Gyan Harwood, Heli Salmela, Dalial Freitak, and Gro Amdam Social immunity is a suite of behavioral and physiological traits that allow colony members to protect one another from pathogens and includes the oral transfer of immunological compounds between nestmates. In honey bees, royal jelly is a glandular secretion produced by a subset of workers that is fed to the queen and young larvae, and which contains many antimicrobial compounds. A related form of social immunity, transgenerational immune priming (TGIP), allows queens to transfer pathogen fragments into their developing eggs where they are recognized by the embryo's...
Source: Journal of Experimental Biology - March 2, 2021 Category: Biology Authors: Harwood, G., Salmela, H., Freitak, D., Amdam, G. Tags: RESEARCH ARTICLE Source Type: research

Hydrogen isotope assimilation and discrimination in green turtles [RESEARCH ARTICLE]
Laura Pages Barcelo, Jeffrey A. Seminoff, Hannah B. Vander Zanden, T. Todd Jones, Karen A. Bjorndal, Alan B. Bolten, Walter Mustin, Geraldine Busquets-Vass, and Seth D. Newsome Although hydrogen isotopes (2H) are commonly used as tracers of animal movement, minimal research has investigated the use of 2H as a proxy to quantify resource and habitat use. While carbon and nitrogen are ultimately derived from a single source (food), the proportion of hydrogen in consumer tissues originates from two distinct sources: body water and food. Before hydrogen isotopes can be effectively used as a resource and habitat tracer, we need ...
Source: Journal of Experimental Biology - March 2, 2021 Category: Biology Authors: Pages Barcelo, L., Seminoff, J. A., Vander Zanden, H. B., Jones, T. T., Bjorndal, K. A., Bolten, A. B., Mustin, W., Busquets-Vass, G., Newsome, S. D. Tags: RESEARCH ARTICLE Source Type: research

CRISPR/Cas9 mutagenesis reveals a role for ABCB1 in gut immune responses to Vibrio diazotrophicus in sea urchin larvae [RESEARCH ARTICLE]
Travis J. Fleming, Catherine S. Schrankel, Himanshu Vyas, Hannah D. Rosenblatt, and Amro Hamdoun The ABC transporter ABCB1 plays an important role in the disposition of xenobiotics. Embryos of most species express high levels of this transporter in early development as a protective mechanism, but its native substrates are not known. Here we used larvae of the sea urchin Strongylocentrotus purpuratus to characterize the early life expression and role of Sp-ABCB1a, a homolog of ABCB1. The results indicate that while Sp-ABCB1a is initially expressed ubiquitously, it becomes enriched in the developing gut. Using optimized CRIS...
Source: Journal of Experimental Biology - March 2, 2021 Category: Biology Authors: Fleming, T. J., Schrankel, C. S., Vyas, H., Rosenblatt, H. D., Hamdoun, A. Tags: RESEARCH ARTICLE Source Type: research

Progeny of Xenopus laevis from altitudinal extremes display adaptive physiological performance [RESEARCH ARTICLE]
This study is one of few demonstrating potential intraspecific evolution of critical thermal limits in a vertebrate species. Multi-generation common garden experiments and genetic analyses would be required to further tease apart the relative contribution of plastic and genetic effects to the adaptive phenotypic variation observed in these tadpoles. (Source: Journal of Experimental Biology)
Source: Journal of Experimental Biology - March 2, 2021 Category: Biology Authors: Wagener, C., Kruger, N., Measey, J. Tags: RESEARCH ARTICLE Source Type: research

Auditory perception of self and others in zebra finches: evidence from an operant discrimination task [RESEARCH ARTICLE]
Nicole Geberzahn, Sandor Zsebok, and Sebastien Deregnaucourt Vocal communication is essential for social interactions in many animal species. For this purpose an animal has to perceive vocal signals of conspecifics and is often also required to discriminate conspecifics. The capacity to discriminate conspecifics is particularly important in social species in which individuals interact repeatedly. In addition, auditory perception of self plays an important role for vocal learners. It allows a vocal learner to memorise vocalisations of conspecifics and to subsequently modify its own vocalisations in order to match the memori...
Source: Journal of Experimental Biology - March 2, 2021 Category: Biology Authors: Geberzahn, N., Zsebok, S., Deregnaucourt, S. Tags: RESEARCH ARTICLE Source Type: research