Journal of Experimental Biology最新文献_第4页

Older adults do not have a higher metabolic cost than younger adults in outdoor overground walking. 老年人在户外地面行走时的代谢成本并不比年轻人高。

IF 3 2区生物学

Journal of Experimental Biology Pub Date : 2026-10-01 Epub Date: 2026-10-09 DOI: 10.1242/jeb.252654

Eline van der Kruk, Koen J P Jongbloed, Monica Orlandi, Michael F Miller, Anne K Silverman

{"title":"Older adults do not have a higher metabolic cost than younger adults in outdoor overground walking.","authors":"Eline van der Kruk, Koen J P Jongbloed, Monica Orlandi, Michael F Miller, Anne K Silverman","doi":"10.1242/jeb.252654","DOIUrl":"10.1242/jeb.252654","url":null,"abstract":"The metabolic cost of walking is widely used to evaluate human performance and the effectiveness of clinical interventions. Decades of laboratory research, largely based on treadmill experiments, have established a canonical relationship between walking speed and metabolic cost, and suggested that ageing shifts this relationship upward, implying reduced efficiency in older adults. However, this relationship has not been well tested during overground walking across matched speeds. We compared healthy younger (n=16; 26±2 years) and older (n=11; 74±3 years) adults across eight outdoor overground walking trials at different speeds: preferred walking speed (PWS), three fixed speeds (0.8, 1.2, 1.6 m s-1) and four speeds at ±5% and ±10% of PWS. Contrary to our hypothesis, older adults did not show higher gross or net metabolic cost of walking (GCOW and NCOW) than younger adults at any speed; rather, both trended consistently lower in older adults, reaching significance for GCOW at 0.8 m s-1 only. Comparisons of resting metabolic rate and respiratory exchange ratio to prior reference groups did not indicate that our older cohort was unusually fit. Independent of age, GCOW was significantly higher at 0.8 m s-1 than at the remaining speeds (1.2 to 1.6 m s-1), confirming that walking at slower speeds increases GCOW. These findings challenge the view that ageing intrinsically increases the energetic cost of walking, suggesting instead that previously reported upward shifts in cost may reflect treadmill-specific constraints or speed effects. Future work is needed to explore direct comparisons of outdoor, overground walking with treadmill walking at fixed speeds in both younger and older adults.","PeriodicalId":15786,"journal":{"name":"Journal of Experimental Biology","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149012547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Walking in circles: linking high- and low-level parameter scaling of visually guided and spontaneous turning behaviour. 绕圈行走：连接视觉引导和自发转向行为的高、低参数缩放。

IF 3 2区生物学

Journal of Experimental Biology Pub Date : 2026-10-01 Epub Date: 2026-10-06 DOI: 10.1242/jeb.252608

Merit Meschenmoser, Volker Dürr

{"title":"Walking in circles: linking high- and low-level parameter scaling of visually guided and spontaneous turning behaviour.","authors":"Merit Meschenmoser, Volker Dürr","doi":"10.1242/jeb.252608","DOIUrl":"10.1242/jeb.252608","url":null,"abstract":"The ability to change one's current heading, i.e. to turn, is essential for all walking animals. While several studies have addressed how leg movement or inter-leg coordination may change during turning, relatively little is known about how turning-related changes at the level of single-leg stepping (low level) scale with turn magnitude at the level of body trajectories (high level). Here, we used spontaneous and visually induced turns of unrestrained walking stick insects to test (i) how high-level parameters of unrestrained turning scale with low-level parameters of leg movement, and (ii) the effect of visual guidance on turning parameters. To this end, we used a step change in stationary landmark position in an open-field arena to constrain the timing and magnitude of target-directed turns. These visually guided turns were compared with spontaneous turns in an all-white condition without guiding landmarks. We show that visually induced turns were walked at a greater forward velocity and had fewer short steps than spontaneous turns. The scaling of turning responses was dominated by an increase in turning duration (factor 1.87) rather than turning speed (factor 1.32). Increased rotational velocity correlated with reduced forward velocity, though with flexible timing of both effects. These changes were accompanied by larger shifts in step direction, as well as an increased asymmetry of step types between inner and outer legs, suggesting a mix of distinct turning strategies that depend on overall turn angle. Future models on six-legged locomotion should thus consider the incorporation of more than one mechanism to govern turning.","PeriodicalId":15786,"journal":{"name":"Journal of Experimental Biology","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148906343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Exercise training induces muscle remodeling independent of estrogen-related receptor (ERR) expression in adult zebrafish. 在成年斑马鱼中，运动训练诱导独立于雌激素相关受体（ERR）表达的肌肉重塑。

IF 3 2区生物学

Journal of Experimental Biology Pub Date : 2026-10-01 DOI: 10.1242/jeb.252349

Riley K Mantulak, Simer K Gill, Giulia S Rossi, Alexander G Little

{"title":"Exercise training induces muscle remodeling independent of estrogen-related receptor (ERR) expression in adult zebrafish.","authors":"Riley K Mantulak, Simer K Gill, Giulia S Rossi, Alexander G Little","doi":"10.1242/jeb.252349","DOIUrl":"10.1242/jeb.252349","url":null,"abstract":"Locomotor capacity is a major determinant of fitness and is strongly modulated by exercise-induced physiological plasticity. In vertebrates, sustained submaximal exercise typically promotes a shift toward an aerobic muscle phenotype, characterized by enhanced oxidative capacity, angiogenesis and contractile remodeling. In mammals, these plastic responses are largely mediated by estrogen-related receptors (ERRs) and their coregulators; however, whether these regulatory mechanisms are conserved in fish remains unclear. Here, we tested the role of ERRs in exercise acclimation in adult zebrafish (Danio rerio), a laboratory model with multiple ERR paralogs following teleost-specific genome duplication events. Following 6 weeks of moderate intensity forced-swimming training, we assessed whole-animal performance (critical swimming speed) and metabolism alongside skeletal muscle contractile and metabolic phenotypes. We applied proteomic profiling and pathway enrichment analyses to evaluate changes in ERR expression and activity, and to identify molecular networks associated with muscle remodeling. Exercise training improved locomotor performance by increasing critical swimming speed and induced skeletal muscle remodeling consistent with a more oxidative and vascularized phenotype, without detectable changes in resting or maximal metabolic rates. Additionally, improvements in exercise training capacity were not accompanied by detectable changes in ERR expression as determined by proteomic analyses. Instead, it suggested alternative regulation distinct from canonical mammalian ERR signaling pathways. Our results demonstrate that zebrafish exhibit conserved exercise-induced phenotypic outcomes but rely on fundamentally different molecular mechanisms than mammals. These findings highlight the value and limitations of zebrafish as models for exercise physiology and underscore the evolutionary flexibility of signaling pathways governing conserved functional phenotypes.","PeriodicalId":15786,"journal":{"name":"Journal of Experimental Biology","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148840114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Elevated hemolymph protein and branched-chain amino acids are associated with fungal Metarhizium growth and host mortality in the desert locust, Schistocerca gregaria. 血淋巴蛋白和支链氨基酸的升高与沙漠蝗虫绿僵菌的生长和宿主死亡率有关。

IF 3 2区生物学

Journal of Experimental Biology Pub Date : 2026-10-01 Epub Date: 2026-09-30 DOI: 10.1242/jeb.253238

Syeda Mehreen Tahir, Tamir Lichaa, Thy Nguyen, Stephanie Nunez, Nicholas Rolig, Stefan Jaronski, Brian Cherry, Syed Muaaz, Arianne J Cease, Jon F Harrison

{"title":"Elevated hemolymph protein and branched-chain amino acids are associated with fungal Metarhizium growth and host mortality in the desert locust, Schistocerca gregaria.","authors":"Syeda Mehreen Tahir, Tamir Lichaa, Thy Nguyen, Stephanie Nunez, Nicholas Rolig, Stefan Jaronski, Brian Cherry, Syed Muaaz, Arianne J Cease, Jon F Harrison","doi":"10.1242/jeb.253238","DOIUrl":"10.1242/jeb.253238","url":null,"abstract":"Dietary macronutrient balance is a major determinant of infection outcomes, yet the mechanisms linking host nutrition to pathogen success remain poorly understood. In the desert locust, Schistocerca gregaria, protein-biased diets enhance several markers of immune function but paradoxically increase susceptibility to infection by the entomopathogenic fungus Metarhizium robertsii. We hypothesized that dietary protein may benefit the pathogen by increasing access to host nutritional resources, and predicted that protein-biased diets would increase hemolymph concentrations of total protein and branched-chain amino acids, nutrients known to support Metarhizium growth, and that infection would cause declines in these compounds. We also hypothesized that infected locusts would behaviorally compensate by shifting nutrient intake toward a more resistant, carbohydrate-biased intake target. To test these predictions, we examined how dietary protein-to-carbohydrate balance influenced hemolymph nutrient reserves and nutrient intake behavior following fungal infection. Protein-biased diets increased total hemolymph protein and concentrations of 8 out of 12 amino acids measured, but did not affect hemolymph glucose or trehalose concentrations. Infection caused declines in glucose, protein, the three branched chain amino acids and tyrosine. Infected locusts did not alter nutrient intake behavior. Together, these findings are consistent with the hypothesis that protein-biased diets accelerate mortality during fungal infection by creating a more favorable nutritional environment for the pathogen.","PeriodicalId":15786,"journal":{"name":"Journal of Experimental Biology","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148880682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Repeated competition influences neural response, but not neurogenesis or physiology, in the fighting fish Betta splendens. 反复的竞争影响斗鱼的神经反应，但不影响神经发生或生理。

IF 3 2区生物学

Journal of Experimental Biology Pub Date : 2026-10-01 Epub Date: 2026-10-06 DOI: 10.1242/jeb.252766

Jeremy A Spool, Alexander J A Heywood, Ruth E W Berganross, Elaine A Aquino, Temidayo D Bambe, Kelly J Wallace

{"title":"Repeated competition influences neural response, but not neurogenesis or physiology, in the fighting fish Betta splendens.","authors":"Jeremy A Spool, Alexander J A Heywood, Ruth E W Berganross, Elaine A Aquino, Temidayo D Bambe, Kelly J Wallace","doi":"10.1242/jeb.252766","DOIUrl":"10.1242/jeb.252766","url":null,"abstract":"Territorial competition has costs such as wounds received, energy spent and elevated stress. How does Betta splendens, a species that has been artificially selected for enhanced territorial aggression, maintain high levels of metabolically costly displays (gill flaring) over repeated days of territorial competition? Here, we conducted two experiments. The first exposed male B. splendens to a size-matched unresolvable competition (a mirror) daily for 3 weeks. We found that B. splendens indeed maintained gill flaring throughout the competition schedule and exhibited no baseline stress impacts (measured via a scototaxis assay). We then exposed B. splendens to 1, 2 or 3 weeks of competition and quantified cortisol levels, neurogenesis and the neural response in brain regions associated with social processing. We again found that B. splendens showed consistently elevated gill flaring and no impact on stress (measured via waterborne cortisol). Competition-exposed fish displayed an increased neural response in the caudal supracommissural nucleus of the ventral telencephalon (Vs), a region that is homologous to the mammalian medial amygdala/bed nucleus of the stria terminalis and a central mediator of social decision making. The neural response in this same region positively correlated with individual variation in gill flaring. Competition did not influence neurogenesis (doublecortin expression). Lastly, a measure of reproductive investment (gonadosomatic index) did not correlate to behavior but did correlate to cortisol levels, suggesting a cohesive physiological state related to reproduction in this species. Taken together, this work details the mechanisms that are relevant to the maintenance of costly aggressive behavior.","PeriodicalId":15786,"journal":{"name":"Journal of Experimental Biology","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148880738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Emulating the influence of exoskeleton stiffness on primary afferent feedback in rat isolated muscle-tendon unit. 模拟外骨骼刚度对大鼠离体肌肉-肌腱单元初级传入反馈的影响。

IF 3 2区生物学

Journal of Experimental Biology Pub Date : 2026-09-29 DOI: 10.1242/jeb.252345

Amro A Alshareef, Paul Nardelli, Surabhi N Simha, Timothy C Cope, Lena H Ting, Gregory S Sawicki

{"title":"Emulating the influence of exoskeleton stiffness on primary afferent feedback in rat isolated muscle-tendon unit.","authors":"Amro A Alshareef, Paul Nardelli, Surabhi N Simha, Timothy C Cope, Lena H Ting, Gregory S Sawicki","doi":"10.1242/jeb.252345","DOIUrl":"10.1242/jeb.252345","url":null,"abstract":"Exoskeletons assist and augment movement, but their effects on proprioceptive feedback remain poorly understood due to challenges in making direct measures of sensory signals in humans. Here, we leveraged a benchtop animal model to explore how mechanical context akin to an elastic exoskeleton operating on a human lower limb joint influences primary muscle spindle firing. In an anesthetized rat preparation, we applied controlled stretches to the medial gastrocnemius with engineered springs (0-0.5 N/mm) in parallel to the muscle-tendon unit (MTU) while modulating muscle activation to maintain overall system stiffness. Fascicle length was measured with sonomicrometry, force and MTU length with a servo motor, and spindle instantaneous firing rate (IFR) using dorsal root recordings. Trading off increases in exoskeleton stiffness with reductions in muscle activation decreased biological muscle force (3.1±0.6 N to 1.6±0.6 N, p<0.001) and stiffness (4.4±1.5 N/mm to 2.3±1.3 N/mm, p<0.01), and increased fascicle length (7.9±1.3 mm to 8.3±1.5 mm, p<0.005). We found significant correlations between spindle firing and each independent fascicle dynamics factor we investigated (p<0.005). Thus, parallel stiffness modified muscle fascicle dynamics but did not alter spindle firing, possibly due to internal trade-offs in the salient fascicle dynamics that drive spindle behavior. Leveraging in-situ experiments that enable monitoring of afferent feedback in complex mechanical contexts such as added parallel stiffness can provide a window into the effects of wearable devices on underlying sensory systems.","PeriodicalId":15786,"journal":{"name":"Journal of Experimental Biology","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149074898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Heart Rate Supports Accelerometry as a Reliable Predictor of Energy Expenditure in Bats. 心率支持加速度计作为蝙蝠能量消耗的可靠预测指标。

IF 3 2区生物学

Journal of Experimental Biology Pub Date : 2026-09-24 DOI: 10.1242/jeb.251521

Travis D Bayer, M Graciela Aguilar, Leslye M Barría, Luisa F Gómez-Feuillet, James P Lee, M Teague O'Mara

{"title":"Heart Rate Supports Accelerometry as a Reliable Predictor of Energy Expenditure in Bats.","authors":"Travis D Bayer, M Graciela Aguilar, Leslye M Barría, Luisa F Gómez-Feuillet, James P Lee, M Teague O'Mara","doi":"10.1242/jeb.251521","DOIUrl":"https://doi.org/10.1242/jeb.251521","url":null,"abstract":"Measuring the energetic cost of behavior is essential for understanding decision-making in wild animals. This is particularly true for bats where life near their energetic ceiling has resulted in a diversity of behaviors to compensate for social and environmental unpredictability. While GPS and tri-axial accelerometry has improved movement-based estimates of energy expenditure in the field, complex flight kinematics in bats may violate key assumptions accelerometry-based estimates rely on. To test whether energy expenditure is predicted by acceleration-based movement in bats, we deployed heart rate loggers alongside GPS with tri-axial accelerometers on free-ranging greater spear-nosed bats (Phyllostomus hastatus) in Panamá. We hypothesized that heart rate would positively reflect increases in Vectorial Dynamic Body Acceleration (VeDBA), a commonly used proxy for energy expenditure, and that including information on behavior would enhance this relationship. We also hypothesized that heart rate and VeDBA would reflect theoretical speed-power curves of flight. We found VeDBA had a strong positive relationship with heart rate, and model accuracy improved when behavioral states of flying and not flying were defined. Additionally, incorporating behavioral duration and sequence number improved predictions, showing that temporal context and activity patterns further refine estimates of energy expenditure. The relationship between VeDBA and airspeed resembled the mechanical power curve previously estimated for P. hastatus, supporting the relevance of aerodynamic theory in interpreting bat energetics. Overall, acceleration-based estimates reliably predict energy expenditure in free-ranging P. hastatus and incorporating behavior improves model accuracy and ecological relevance, providing a powerful tool for understanding energy allocation in wild bats.","PeriodicalId":15786,"journal":{"name":"Journal of Experimental Biology","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149030587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Phenanthrene disrupts calcium transients and inhibits INCX in zebrafish (Danio rerio) ventricular myocytes. 菲在斑马鱼（Danio rerio）心室肌细胞中破坏钙瞬态并抑制INCX。

IF 3 2区生物学

Journal of Experimental Biology Pub Date : 2026-09-24 DOI: 10.1242/jeb.252945

Eeva-Riikka Vehniäinen, Charlotte R Marris, Shiva Nag Kompella, Jules C Hancox, Holly A Shiels

引用次数: 0

Surface texture guides egg-laying decisions in Aedes aegypti mosquitoes. 埃及伊蚊的表面纹理指导其产卵决定。

IF 3 2区生物学

Journal of Experimental Biology Pub Date : 2026-09-21 DOI: 10.1242/jeb.252599

Aleksandra Anoshina, Nicholas K Tochor, Lauren Semkow, Annie Zeng, Benjamin J Matthews

引用次数: 0

Bees exhibit behavioural flexibility to learned visual cues to prevent negative consequences during navigation in clutter. 蜜蜂对习得的视觉线索表现出行为灵活性，以防止在混乱中导航时产生负面后果。

IF 3 2区生物学

Journal of Experimental Biology Pub Date : 2026-09-21 DOI: 10.1242/jeb.252013

Manon Jeschke, Maximilian Stahlsmeier, Olivier J N Bertrand, Martin Egelhaaf

{"title":"Bees exhibit behavioural flexibility to learned visual cues to prevent negative consequences during navigation in clutter.","authors":"Manon Jeschke, Maximilian Stahlsmeier, Olivier J N Bertrand, Martin Egelhaaf","doi":"10.1242/jeb.252013","DOIUrl":"https://doi.org/10.1242/jeb.252013","url":null,"abstract":"Bumblebees navigate complex environments where collisions with obstacles can impair flight performance. While bees possess innate collision avoidance reflexes, they may benefit from learning to identify and avoid high-risk collision areas using environmental cues. However, the temporal dynamics of how bees form associations between visual cues and collision experiences remain unclear. We investigated whether bumblebees associate visual cues perceived before or after collision events with a collision avoiding movement direction. Individual foragers were trained to navigate through a flight tunnel containing a transparent barrier and an LED panel that switched colours immediately after the bee's first collision. Following training, we tested bees' responses to each colour cue without the barrier. Bees demonstrated significant preferences for avoiding the previously blocked side when presented with either the colour shown before the first collision (81% avoidance-consistent choice) or the colour shown after the first collision (71% avoidance-consistent choice), while showing no preference when no colour cue was presented. These results are consistent with bees forming associations with visual cues encountered in different time windows relative to negative experiences. However, an equally plausible interpretation is that the bees learned primarily the association with the visual cue they saw before the first collision and then translated this learned response to the related, but distinguishable, cue they saw after the first collision. Both interpretations demonstrate considerable flexibility with which bees form and deploy memories to aid navigation in cluttered environments.","PeriodicalId":15786,"journal":{"name":"Journal of Experimental Biology","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149012544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0