Ecological and evolutionary physiology最新文献

{"title":"Personality, Performance, and Corticosterone in White-Footed Mice.","authors":"Paul Agnani, Kathleen Gilmour, Vincent Careau","doi":"10.1086/739815","DOIUrl":"10.1086/739815","url":null,"abstract":"<p><p>AbstractPrevious small rodent studies report a negative correlation between exploration and locomotor performance. In other words, individuals that are more exploratory during a novel environment test run more slowly on a racetrack during a forced-exercise test. Given that measuring both exploration and sprint speed involves stress (novelty, open space, stimuli to prompt running), glucocorticoid hormones may play a role in the negative exploration-speed relationship. We repeatedly measured exploration, sprint speed, and blood corticosterone levels in 51 captive female white-footed mice. As in prior rodent studies, exploration and sprint speed were negatively correlated at the among-individual level. Moreover, contrasting relationships were obtained between corticosterone and exploration (baseline corticosterone, <math><mrow><mi>r</mi><mo>=</mo><mn>-0.523</mn></mrow></math>; postexercise corticosterone, <i>r</i> = -0.290) and between corticosterone and sprint speed (baseline corticosterone, <math><mrow><mi>r</mi><mo>=</mo><mn>0.306</mn></mrow></math>; postexercise corticosterone, <i>r</i> = 0.400). Accordingly, the exploration-sprint speed correlation was halved (from <math><mrow><msub><mi>r</mi><mrow><mi>ind</mi></mrow></msub><mo>=</mo><mn>-0.272</mn></mrow></math> to <i>r</i>_ind = -0.129) when conditioning on both baseline and postexercise corticosterone (measured 3 min after the forced-exercise tests). Considering the overall strength and direction of the associations between baseline versus postexercise corticosterone and behavior versus performance, our results support the hypothesis that glucocorticoid stress hormones play a role in the observed negative relationship between exploration and locomotor performance.</p>","PeriodicalId":519900,"journal":{"name":"Ecological and evolutionary physiology","volume":"99 1","pages":"43-55"},"PeriodicalIF":1.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147349976","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Negative Effects of Excessive Heat on Colony Thermoregulation and Population Dynamics in Honeybees.","authors":"Jun Chen, Adrian Fisher, Gloria DeGrandi-Hoffman, Cahit Ozturk, Brian H Smith, Jennifer H Fewell, Yun Kang, Kylie Maxwell, Kynadi Overcash, Keerut Chahal, Jon F Harrison","doi":"10.1086/739493","DOIUrl":"10.1086/739493","url":null,"abstract":"<p><p>AbstractHoneybees (<i>Apis mellifera</i>) are essential for the pollination and yield of many crops and have experienced significant mortality in recent years. While climatic warming has been suggested as a possible cause of honeybee losses, their responses to warming conditions and heat waves remain poorly understood. Honeybee colonies have well-documented mechanisms to cope with heat exposure. However, there have been no studies to date that have assessed the limits of such thermoregulation or how natural heat waves affect the capacity of honeybee colonies to thermoregulate and grow. To test the hypothesis that excessive heat impairs honeybee colony growth by exceeding colonial thermoregulatory capacity, we studied how variation in summer temperatures affected hive temperature regulation and colony growth during a desert summer in which maximal shaded air temperatures intermittently exceeded 40°C. We monitored the growth of nine colonies biweekly for 3 mo and recorded temperatures at the center and edge frames of the brood nest and on combs at the outer edge of the hive body. Average temperatures in the brood center and edge were quite stable and within the optimal range of 34°C-36°C that is necessary for healthy brood development throughout the summer. However, all hive locations exhibited cyclic, diurnal thermal fluctuations, and broods experienced considerable portions of each day (14% for the brood center, 33% for the brood edge) above and below the optimal temperature range. Higher maximal air temperatures and greater temperature fluctuations within the hive led to declines in colony population. These findings suggest that excessive heat, with maximal temperatures exceeding 40°C, can reduce colony populations by impairing the thermoregulation of broods or by exposing adults to temperatures that shorten their lifespans. If excessive heat periods occur more frequently as predicted as a result of climate change, this could limit regions where colonies can successfully survive the summer.</p>","PeriodicalId":519900,"journal":{"name":"Ecological and evolutionary physiology","volume":"99 1","pages":"1-18"},"PeriodicalIF":1.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147349692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reassessing Hybrid Vigor or Hybrid Dysfunction Using Physiological Trade-Offs in an Endangered Salamander System.","authors":"Benjamin M Fitzpatrick, Evin T Carter, Lindsey E Hayter, Matthew J Chaney, Bryan C Eads, H Bradley Shaffer","doi":"10.1086/739792","DOIUrl":"10.1086/739792","url":null,"abstract":"<p><p>AbstractFitness of interspecific hybrids can be higher or lower than that of their parental genotypes, with major ramifications for evolution and conservation. A recent study found that hybrid tiger salamanders had higher metabolic rates than their parental forms. Specifically, the ratio of resting metabolic rate to water loss, which was used as a measure of performance, was greater in hybrids. Recent genetic research showed that over half of the experimental subjects in that study were genetically pure California tiger salamanders (<i>Ambystoma californiense</i>) misclassified as hybrids. We reanalyzed the data using the corrected identification of hybrids and parentals. As expected, updating the classification revealed even stronger evidence for differences between hybrids and parentals. Hybrids had higher resting metabolic rates and greater water loss than parentals. The ratio of resting metabolic rate to water loss was also higher in hybrids. However, we suggest that this ratio might not be a positive measure of salamander performance. Higher metabolic rate means higher energy expenditure, and higher water loss suggests increased risk of desiccation. Both are major challenges for terrestrial amphibians, especially salamanders, which are hypothesized to be low-energy, low-water-loss specialists. Under this hypothesis, the ratio of energy expenditure to water loss is a ratio of two costs rather than a ratio of benefit to cost. While our analyses corroborate and strengthen the previous statistical results, we suggest that high resting metabolic rate is better interpreted as hybrid dysfunction, not vigor. Both hypotheses are speculative, and specific research on the fitness effects of these physiological differences is needed to resolve this important ecological question.</p>","PeriodicalId":519900,"journal":{"name":"Ecological and evolutionary physiology","volume":"99 1","pages":"33-42"},"PeriodicalIF":1.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147349966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dietary n-3 Long-Chain Polyunsaturated Fatty Acids Alter the Thermoregulatory Phenotype of a Migratory Shorebird.","authors":"Kevin G Young, Morag F Dick, Catherine M Ivy, Christopher G Guglielmo","doi":"10.1086/739491","DOIUrl":"10.1086/739491","url":null,"abstract":"<p><p>AbstractMigrating birds balance high energy expenditure required in flight with extended bouts of feeding at stopover to refuel, and strategies that permit birds to conserve energy during migration could benefit their overall performance. Energy conservation through reduced body temperature permits animals to save energy, similar to controlled heterothermy (i.e., torpor). Furthermore, dietary n-3 long-chain polyunsaturated fatty acids have been hypothesized to prime flight muscles to improve migration performance, although this has not been tested in a thermoregulatory framework. Here, we test how the energetic and thermoregulatory performance of western sandpipers (<i>Calidris mauri</i>) is influenced by dietary n-3 long-chain polyunsaturated fatty acids. Dietary fatty acid manipulations did not affect basal, resting, or summit metabolic rate in response to cold. Birds also had a similar body temperature at rest over 24 h regardless of diet. However, sandpipers fed a diet high in n-3 long-chain polyunsaturated fatty acids had lower body temperature after a response to cold (<math><mrow><mn>5.98</mn><mo>±</mo><mn>1.80</mn></mrow></math> [SE]), and lower body temperature was associated with reduced metabolic rates at low temperatures in comparison to birds fed a high-monounsaturated fatty acid diet. These results indicate that n-3 long-chain polyunsaturated fatty acids change the thermoregulatory phenotype of western sandpipers but without consistent changes in energetics using standard measurements. Our findings suggest that ecological variation in the availability of different dietary fatty acids could affect thermoregulation in shorebirds. Increasing sea surface temperatures may reduce the availability of n-3 long-chain polyunsaturated fatty acids, making it important to understand their role in the physiology and performance of animals that consume them in high abundance.</p>","PeriodicalId":519900,"journal":{"name":"Ecological and evolutionary physiology","volume":"99 1","pages":"19-32"},"PeriodicalIF":1.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147350262","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Hemoglobin-O₂ Affinity on Breathing and Gas Exchange in Deer Mice.","authors":"Caroline Holicka, Graham R Scott","doi":"10.1086/739050","DOIUrl":"10.1086/739050","url":null,"abstract":"<p><p>AbstractEvolved increases in hemoglobin (Hb)-O₂ affinity are common across high-altitude mammals and birds, but the downstream physiological effects of such increases remain poorly understood. In deer mice (<i>Peromyscus maniculatus</i>), the genetic variants of α- and β-globin in high-altitude populations are also associated with evolved changes in breathing pattern and the hypoxic ventilatory response, raising the question of whether chronic increases in Hb-O₂ affinity affect breathing and gas exchange in this species. We tested this possibility in lab-raised deer mice from low-altitude populations by pharmacologically increasing Hb-O₂ affinity over 4 wk using cyanate. Treatments were conducted during adulthood and early postnatal development in normoxia to examine whether the influence of Hb-O₂ affinity is life stage specific. Breathing, arterial O₂ saturation, and aerobic metabolism (O₂ consumption rate) were then measured in normoxia, hypoxia (10% O₂), and hypoxic hypercarbia (10% O₂, 3% CO₂). Cyanate-treated mice experienced pronounced decreases in O₂ pressure at 50% Hb saturation compared to saline-treated controls and exhibited corresponding increases in arterial O₂ saturation in hypoxic conditions in both adults and juveniles. Total ventilation increased and metabolism decreased in hypoxia and hypoxic hypercarbia, but cyanate had little to modest effects on these responses. Effects of cyanate on breathing frequency, tidal volume, and the relationship between total ventilation and tidal volume (an indicator of breathing pattern) were also modest and inconsistent between adults and juveniles. The results suggest that chronic increases in Hb-O₂ affinity have no clear and consistent effects on breathing pattern or the hypoxic ventilatory response.</p>","PeriodicalId":519900,"journal":{"name":"Ecological and evolutionary physiology","volume":"98 6","pages":"355-368"},"PeriodicalIF":1.7,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145967835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sclerotization Protects <i>Drosophila nigrospiracula</i> against Parasitism by Ectoparasitic Mites.","authors":"Sean Chua, Collin J Horn, Lien T Luong","doi":"10.1086/738729","DOIUrl":"10.1086/738729","url":null,"abstract":"<p><p>AbstractThe cuticle of arthropods provides the first line of defense against predators, pathogens, and parasites. While most studies focus on the role of cuticular defense against microbial pathogens, few have examined whether the cuticle protects against parasites. Here, we investigate the relative importance of cuticular sclerotization and behavioral defenses in <i>Drosophila nigrospiracula</i> against an ectoparasite (<i>Macrocheles subbadius</i>). We first tested whether newly eclosed (NE; i.e., teneral) flies are more susceptible to parasitism than fully sclerotized (FS) flies. In a separate experiment, we severed the wings to test whether the differential susceptibility between NE and FS flies was explained by wing-mediated defenses. We also performed endurance (negative geotaxis) assays to determine whether reduced physical endurance among NE flies contributed to higher vulnerability to parasitism. We found that regardless of whether wings were intact or removed, the prevalence and intensity of infection was significantly higher among NE flies than among FS flies. The negative geotaxis assay also showed that NE flies had lower endurance than FS flies. Moreover, differences in the probability and severity of parasitism between NE and FS flies were magnified when the wings were removed. These results suggest that while cuticular sclerotization serves as the primary first line of defense, wing-mediated behaviors likely allow flies to avoid or minimize mite attacks, and the effectiveness of these behaviors is likely limited by physical endurance. Differences in morphology and behavior between immature adults (not FS) and mature organisms (FS) may drive variation in parasitism risk across developmental stages.</p>","PeriodicalId":519900,"journal":{"name":"Ecological and evolutionary physiology","volume":"98 6","pages":"421-428"},"PeriodicalIF":1.7,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145967980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prior Infection Induces Long-Lasting Partial Immunity to Reduce Transmission within Flocks in an Avian Host-Pathogen System.","authors":"Madeline C Sudnick, Erin L Sauer, Sarah E DuRant","doi":"10.1086/738980","DOIUrl":"10.1086/738980","url":null,"abstract":"<p><p>AbstractPopulation-level differences in the ability to maintain immunity can lead to contrasting survival outcomes between groups and determine how future outbreaks will spread. Pathology and infectiousness during subsequent infections can be influenced by immunity and an increase in resistance or tolerance of individuals. However, determining the longevity and effectiveness of immunity in a wildlife population is challenging because of the lack of infrastructure for long-term monitoring of populations and individuals and for host-pathogen-specific tests. Furthermore, predicting wildlife disease dynamics requires an understanding of individual-level heterogeneity in pathology and behavior, as well as a knowledge of how populations with differing partial immunity will transmit disease, which is currently limited. Using an avian host-pathogen system, we ran two experiments to determine whether previously exposed birds had immunity to <i>Mycoplasma gallisepticum</i> (MG) after 3 yr and whether MG transmission differed between first- and second-infection index birds. Birds retained partial immunity to MG for 3 yr after their original infection and showed signs of being resistant to infection. The transmission experiment revealed that although first- and second-infection index birds experienced pathology and pathogen growth, only first-infection birds transmitted MG. Here, 3 yr could represent lifetime protection for individuals who survive their first infection and a reduction in risk for other members of their flock. Our research has important implications for understanding MG epidemics in wild populations of birds and disease in wildlife more broadly.</p>","PeriodicalId":519900,"journal":{"name":"Ecological and evolutionary physiology","volume":"98 6","pages":"399-411"},"PeriodicalIF":1.7,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145968025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Short-Term Telomere Elongation in Breeding Adults of a Long-Lived Seabird.","authors":"Mauricio Guillen-Parra, Alberto Velando, Bibiana Montoya, Roxana Torres","doi":"10.1086/738557","DOIUrl":"10.1086/738557","url":null,"abstract":"<p><p>AbstractTelomere dynamics have been linked to differences in reproductive effort across vertebrates. In the Cocos booby (<i>Sula brewsteri</i>), we predicted that parents' telomeres would shorten according to their breeding effort during incubation. During mid-incubation, we blood-sampled 24 adults to estimate telomere length by a quantitative polymerase chain reaction and recorded their body mass, clutch size, and hatching success. At the end of incubation, a second body mass measurement and blood sample were collected. Unexpectedly, parents' telomere length increased throughout incubation. Individuals with two-egg clutches, higher hatching success, and increased body mass exhibited greater telomere elongation. Thus, telomere dynamics did not reflect costs of reproductive effort. The results suggest that telomeres elongate, probably depending on individual quality differences, as proposed by the excess resources elongation hypothesis. Future studies should investigate whether the observed short-term telomere elongation is widespread in breeding animals, as it may be part of a potential mechanism for resilience to predictable stressful events like reproduction.</p>","PeriodicalId":519900,"journal":{"name":"Ecological and evolutionary physiology","volume":"98 6","pages":"412-420"},"PeriodicalIF":1.7,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145968042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Honesty Is Costly in a Deceptive System: Locomotor Costs of Producing Large and Strong Weapons for the Crayfish <i>Cherax destructor</i>.","authors":"Lana A Waller, Simon P Lailvaux, Robbie S Wilson","doi":"10.1086/738377","DOIUrl":"10.1086/738377","url":null,"abstract":"<p><p>AbstractTheory predicts that signals of strength should reliably reflect an individual's fighting ability, with the costs of producing and/or displaying high-quality signals maintaining their reliability. Crustaceans offer a unique system to explore these costs because signal (chela) size and reliability (strength relative to size) can be decoupled-chela muscles are concealed beneath an exoskeleton, allowing some individuals to display large but weak chelae. In this study, we quantified the locomotor costs associated with weapon size and reliability in males and females of the crayfish <i>Cherax destructor</i> using both correlative analyses and experimental manipulations. We measured chela size, strength, and swimming performance of crayfish when intact, after an initial chela removal treatment (control, one, or two), and again after removal of the remaining chela/chelae. We predicted that larger chelae would reduce swimming performance because of added mass and drag and that relatively stronger individuals (greater reliability) would swim slower because of energetic investment in muscle. We found that males and females with larger chelae swam more slowly and that speed increased following the removal of one (11.6%) and two (14.6%) chelae. Individuals with relatively larger chelae showed a greater increase in speed after both chelae were removed. Crayfish with relatively stronger chelae swam more slowly, but this pattern did not hold after chela removal. Our study is the first to demonstrate the independent costs of both signal size and their reliability. While individuals must bear the costs of signaling large weapons, the costs of their reliability may also incentivize the use of unreliable weapons.</p>","PeriodicalId":519900,"journal":{"name":"Ecological and evolutionary physiology","volume":"98 6","pages":"369-380"},"PeriodicalIF":1.7,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145967902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fine-Scale Variation in Optimal Clutch Size in a Blue Tit Population.","authors":"Jorge Garrido-Bautista, Zaida Ortega, Amalia Pérez-Jiménez, Cristina E Trenzado, Pablo Burraco, África Cuadrado-Liñán, Jordi Figuerola, Gregorio Moreno-Rueda","doi":"10.1086/738587","DOIUrl":"10.1086/738587","url":null,"abstract":"<p><p>AbstractClutch size variation may be adaptive in bird populations if parents lay a clutch size that maximizes offspring recruitment. Brood size manipulation experiments allow for testing the optimization of clutch size by studying the effect on nestling body condition and fitness-related physiological traits. If the clutch size is optimized, parents rearing an enlarged brood size are expected to produce low-quality nestlings. Here, we tested this prediction in a population of blue tits (<i>Cyanistes caeruleus</i>), inhabiting two nearby oak forests (differing mainly in humidity) in which blue tits differ in clutch size. We manipulated the brood size (producing reduced, control, and enlarged broods) within each habitat and evaluated the immune system, oxidative status, telomere dynamics, and morphological parameters of the largest and smallest nestlings within broods. We also recorded parental feeding effort and nestling diet composition. Clutch size was higher in the more humid forest, and parents from the two habitats successfully raised the extra nestlings. However, the nestling body mass diminished in enlarged broods compared to control and reduced broods, while the structural size, telomere dynamics, immune system, and oxidative status did not vary with the manipulation treatments. In each forest, parents did not increase their feeding effort in enlarged broods, despite initial between-forest differences in clutch size. Our findings suggest that although blue tits were able to raise extra offspring, clutch size is optimized at the fine scale. Hence, blue tits seem to lay, in every habitat, the clutch size that guarantees the maximal production of high-quality fledglings.</p>","PeriodicalId":519900,"journal":{"name":"Ecological and evolutionary physiology","volume":"98 6","pages":"381-398"},"PeriodicalIF":1.7,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145967824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}