The development of inexpensive and portable point-of-care devices for measuring nutritional physiological parameters from blood (e.g., glucose, ketones) has accelerated our understanding and assessment of real-time variation in human health, but these have infrequently been tested or implemented in wild animals, especially in relation to other key biological or fitness-related traits. Here we used point-of-care devices to measure blood levels of glucose, ketones, uric acid, and triglycerides in free-ranging house finches (Haemorhous mexicanus)—a common songbird in North America that has been well-studied in the context of urbanization, nutrition, health, and sexual selection—during winter and examined (1) repeatability of these methods for evaluating blood levels in these wild passerines, (2) intercorrelations among these measurements within individuals, (3) how blood nutritional-physiology metrics related to a bird's body condition, habitat of origin (urban vs. suburban), poxvirus infection, and sex; and (4) if the expression of male sexually selected plumage coloration was linked to any of the nutritional-physiological metrics. All blood-nutritional parameters were repeatable. Also, there was significant positive covariation between concentrations of circulating triglycerides and glucose and triglycerides and uric acid. Urban finches had higher blood glucose concentrations than suburban finches, and pox-infected individuals had lower blood triglyceride concentrations than uninfected ones. Last, redder males had higher blood glucose, but lower uric acid levels. These results demonstrate that point-of-care devices can be useful, inexpensive ways of measuring real-time variation in the nutritional physiology of wild birds.
{"title":"Using point-of-care devices to examine covariation among blood nutritional-physiological parameters and their relationships with poxvirus infection, habitat urbanization, and male plumage coloration in house finches (Haemorhous mexicanus)","authors":"Kevin J. McGraw, Victor Aguiar de Souza Penha","doi":"10.1002/jez.2796","DOIUrl":"10.1002/jez.2796","url":null,"abstract":"<p>The development of inexpensive and portable point-of-care devices for measuring nutritional physiological parameters from blood (e.g., glucose, ketones) has accelerated our understanding and assessment of real-time variation in human health, but these have infrequently been tested or implemented in wild animals, especially in relation to other key biological or fitness-related traits. Here we used point-of-care devices to measure blood levels of glucose, ketones, uric acid, and triglycerides in free-ranging house finches (<i>Haemorhous mexicanus</i>)—a common songbird in North America that has been well-studied in the context of urbanization, nutrition, health, and sexual selection—during winter and examined (1) repeatability of these methods for evaluating blood levels in these wild passerines, (2) intercorrelations among these measurements within individuals, (3) how blood nutritional-physiology metrics related to a bird's body condition, habitat of origin (urban vs. suburban), poxvirus infection, and sex; and (4) if the expression of male sexually selected plumage coloration was linked to any of the nutritional-physiological metrics. All blood-nutritional parameters were repeatable. Also, there was significant positive covariation between concentrations of circulating triglycerides and glucose and triglycerides and uric acid. Urban finches had higher blood glucose concentrations than suburban finches, and pox-infected individuals had lower blood triglyceride concentrations than uninfected ones. Last, redder males had higher blood glucose, but lower uric acid levels. These results demonstrate that point-of-care devices can be useful, inexpensive ways of measuring real-time variation in the nutritional physiology of wild birds.</p>","PeriodicalId":15711,"journal":{"name":"Journal of experimental zoology. Part A, Ecological and integrative physiology","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jez.2796","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139931439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jorge E. López-Pérez, Jeffrey M. Goessling, Christopher M. Murray
It is well known that hormones influence and direct most facets of physiology; however, there is still contention regarding the directions of certain relationships, for example, between gonadal hormones and immunity. Among the many proposed relationships relating to gonadal–immune interactions, support for immunosuppressive effects of androgens remains prominent within physiological literature. Although ample study has been directed toward the immunosuppressive effects of androgens, considerable disagreement remains regarding their influence on immune function. In this study, we test the hypothesis that androgens inhibit immunocompetence in the American alligator (Alligator mississippiensis). Developing alligators were incubated at female-producing temperatures with a subset of individuals being exposed to 17-α-methyltestosterone (MT) before sexual determination. 17-α-methyltestosterone is a potent androgen, not aromatizable by crocodilians, that has been found to exert masculinizing effects in exposed crocodilian populations in vivo and in vitro. Additionally, a subset of animals was exposed to a novel antigen to quantify innate and acquired immune function. We recovered no significant differences in leukocyte ratios or proportions between groups and found no significant differences in innate immune function as measured by hemolysis-hemagglutination. However, we did find significant differences in acquired immune function, where masculinized individuals expressed greater antibody titers. Our findings reject the hypothesis that androgens suppress immune function; rather, androgens may be immunoenhancing to acquired humoral responses and neutral to innate humoral immunity in crocodilians.
{"title":"Testing androgen-induced immunosuppression: Environmental androgens as a model system for steroid-immune interaction","authors":"Jorge E. López-Pérez, Jeffrey M. Goessling, Christopher M. Murray","doi":"10.1002/jez.2795","DOIUrl":"10.1002/jez.2795","url":null,"abstract":"<p>It is well known that hormones influence and direct most facets of physiology; however, there is still contention regarding the directions of certain relationships, for example, between gonadal hormones and immunity. Among the many proposed relationships relating to gonadal–immune interactions, support for immunosuppressive effects of androgens remains prominent within physiological literature. Although ample study has been directed toward the immunosuppressive effects of androgens, considerable disagreement remains regarding their influence on immune function. In this study, we test the hypothesis that androgens inhibit immunocompetence in the American alligator (<i>Alligator mississippiensis</i>). Developing alligators were incubated at female-producing temperatures with a subset of individuals being exposed to 17-α-methyltestosterone (MT) before sexual determination. 17-α-methyltestosterone is a potent androgen, not aromatizable by crocodilians, that has been found to exert masculinizing effects in exposed crocodilian populations in vivo and in vitro. Additionally, a subset of animals was exposed to a novel antigen to quantify innate and acquired immune function. We recovered no significant differences in leukocyte ratios or proportions between groups and found no significant differences in innate immune function as measured by hemolysis-hemagglutination. However, we did find significant differences in acquired immune function, where masculinized individuals expressed greater antibody titers. Our findings reject the hypothesis that androgens suppress immune function; rather, androgens may be immunoenhancing to acquired humoral responses and neutral to innate humoral immunity in crocodilians.</p>","PeriodicalId":15711,"journal":{"name":"Journal of experimental zoology. Part A, Ecological and integrative physiology","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139905791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cesare Pacioni, Andrey Bushuev, Marina Sentís, Anvar Kerimov, Elena Ivankina, Luc Lens, Diederik Strubbe
Understanding the potential limits placed on organisms by their ecophysiology is crucial for predicting their responses to varying environmental conditions. A main hypothesis for explaining avian thermoregulatory mechanisms is the aerobic capacity model, which posits a positive correlation between basal (basal metabolic rate [BMR]) and summit (Msum) metabolism. Most evidence for this hypothesis, however, comes from interspecific comparisons, and the ecophysiological underpinnings of avian thermoregulatory capacities hence remain controversial. Indeed, studies have traditionally relied on between-species comparisons, although, recently, there has been a growing recognition of the importance of intraspecific variation in ecophysiological responses. Therefore, here, we focused on great tits (Parus major), measuring BMR and Msum during winter in two populations from two different climates: maritime-temperate (Gontrode, Belgium) and continental (Zvenigorod, Russia). We tested for the presence of intraspecific geographical variation in metabolic rates and assessed the predictions following the aerobic capacity model. We found that birds from the maritime-temperate climate (Gontrode) showed higher BMR, whereas conversely, great tits from Zvenigorod showed higher levels of Msum. Within each population, our data did not fully support the aerobic capacity model's predictions. We argued that the decoupling of BMR and Msum observed may be caused by different selective forces acting on these metabolic rates, with birds from the continental-climate Zvenigorod population facing the need to conserve energy for surviving long winter nights (by keeping their BMR at low levels) while simultaneously being able to generate more heat (i.e., a high Msum) to withstand cold spells.
{"title":"Metabolic adjustments to winter severity in two geographically separated great tit (Parus major) populations","authors":"Cesare Pacioni, Andrey Bushuev, Marina Sentís, Anvar Kerimov, Elena Ivankina, Luc Lens, Diederik Strubbe","doi":"10.1002/jez.2790","DOIUrl":"10.1002/jez.2790","url":null,"abstract":"<p>Understanding the potential limits placed on organisms by their ecophysiology is crucial for predicting their responses to varying environmental conditions. A main hypothesis for explaining avian thermoregulatory mechanisms is the aerobic capacity model, which posits a positive correlation between basal (basal metabolic rate [BMR]) and summit (M<sub>sum</sub>) metabolism. Most evidence for this hypothesis, however, comes from interspecific comparisons, and the ecophysiological underpinnings of avian thermoregulatory capacities hence remain controversial. Indeed, studies have traditionally relied on between-species comparisons, although, recently, there has been a growing recognition of the importance of intraspecific variation in ecophysiological responses. Therefore, here, we focused on great tits (<i>Parus major</i>), measuring BMR and <i>M</i><sub>sum</sub> during winter in two populations from two different climates: maritime-temperate (Gontrode, Belgium) and continental (Zvenigorod, Russia). We tested for the presence of intraspecific geographical variation in metabolic rates and assessed the predictions following the aerobic capacity model. We found that birds from the maritime-temperate climate (Gontrode) showed higher BMR, whereas conversely, great tits from Zvenigorod showed higher levels of M<sub>sum</sub>. Within each population, our data did not fully support the aerobic capacity model's predictions. We argued that the decoupling of BMR and M<sub>sum</sub> observed may be caused by different selective forces acting on these metabolic rates, with birds from the continental-climate Zvenigorod population facing the need to conserve energy for surviving long winter nights (by keeping their BMR at low levels) while simultaneously being able to generate more heat (i.e., a high M<sub>sum</sub>) to withstand cold spells.</p>","PeriodicalId":15711,"journal":{"name":"Journal of experimental zoology. Part A, Ecological and integrative physiology","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139899994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Andrea Anabella Barauna, María Inés Conte, Jorge Leandro Leporati, Lorena Beatriz Quiroga, Eduardo Alfredo Sanabria, Miguel Walter Fornés
Testosterone, the primary sex hormone in male lizards, is closely linked to Leydig cell activity (the cells where steroidogenesis occurs) throughout the reproductive cycle, but testosterone action is related to androgen receptors (ARs) distribution in the seminiferous epithelium. In temperate zones, environmental factors detected through the hypothalamic–pituitary–gonadal axis, downregulate plasma testosterone, resulting in a seasonal reproductive cycle. The aim of this work is to study plasma testosterone in adult male lizards of Liolaemus cuyanus, an oviparous species, throughout its reproductive cycle and its relationship with Leydig cell histology, TotalLeydigCell/ActiveLeydigCell (TLC/ALC) ratio, environmental factors (temperature, relative humidity and solar irradiation) and ARs distribution in seminiferous epithelium. Specimens (N = 27) were captured (October to March) in a semi-arid zone (Valle de Matagusanos, San Juan, Argentina) and grouped into three relevant reproductive periods: pre-reproductive (PrR), reproductive (R), and post-reproductive (PsR). Significant differences in plasma testosterone were found among these periods, highest during R than in PsR. A significant positive correlation between plasma testosterone and TLC/ALC ratio was also observed. Plasma testosterone has a significant positive correlation only with solar irradiation, but not with the other variables. In PrR and R, ARs distribution was cytoplasmic and nuclear, shifting to only cytoplasmic in PsR. These results highlight the close correspondence between plasma testosterone, Leydig cell histology and activity, environmental factors, and ARs distribution, resulting in a synchronization that allows males of L. cuyanus to coordinate their reproductive cycle with the most favorable environmental conditions, probably for mating and birth of offspring.
睾酮是雄性蜥蜴的主要性激素,在整个生殖周期中与莱系细胞(类固醇生成的细胞)的活动密切相关,但睾酮的作用与雄激素受体(ARs)在曲细精管上皮细胞中的分布有关。在温带地区,通过下丘脑-垂体-性腺轴检测到的环境因素会下调血浆睾酮,从而导致季节性生殖周期。本研究旨在研究卵生蜥蜴(Liolaemus cuyanus)成年雄性蜥蜴在整个生殖周期中的血浆睾酮及其与Leydig细胞组织学、总Leydig细胞/活性Leydig细胞(TLC/ALC)比率、环境因素(温度、相对湿度和太阳辐射)和ARs在曲细精管上皮细胞中的分布的关系。研究人员在半干旱地区(阿根廷圣胡安马塔古萨诺斯山谷)捕获了标本(N = 27)(10 月至 3 月),并将其分为三个相关生殖期:生殖前期(PrR)、生殖期(R)和生殖后期(PsR)。发现这些时期的血浆睾酮存在显著差异,生殖期的睾酮含量高于生殖后期。血浆睾酮与 TLC/ALC 比率之间也存在明显的正相关。血浆睾酮只与太阳辐照度呈显著正相关,而与其他变量无关。在 PrR 和 R 中,ARs 分布在细胞质和细胞核中,而在 PsR 中则仅分布在细胞质中。这些结果突显了血浆睾酮、莱狄格细胞组织学和活性、环境因素和ARs分布之间的密切对应关系,从而使雄性褐飞虱的生殖周期与最有利的环境条件同步,可能是为了交配和生育后代。
{"title":"Testosterone is closely related to Leydig cell activity, environmental factors, and androgen receptor distribution in adult male lizards of Liolaemus cuyanus (Reptilia: Liolaemidae) during the reproductive cycle","authors":"Andrea Anabella Barauna, María Inés Conte, Jorge Leandro Leporati, Lorena Beatriz Quiroga, Eduardo Alfredo Sanabria, Miguel Walter Fornés","doi":"10.1002/jez.2794","DOIUrl":"10.1002/jez.2794","url":null,"abstract":"<p>Testosterone, the primary sex hormone in male lizards, is closely linked to Leydig cell activity (the cells where steroidogenesis occurs) throughout the reproductive cycle, but testosterone action is related to androgen receptors (ARs) distribution in the seminiferous epithelium. In temperate zones, environmental factors detected through the hypothalamic–pituitary–gonadal axis, downregulate plasma testosterone, resulting in a seasonal reproductive cycle. The aim of this work is to study plasma testosterone in adult male lizards of <i>Liolaemus cuyanus</i>, an oviparous species, throughout its reproductive cycle and its relationship with Leydig cell histology, TotalLeydigCell/ActiveLeydigCell (TLC/ALC) ratio, environmental factors (temperature, relative humidity and solar irradiation) and ARs distribution in seminiferous epithelium. Specimens (<i>N</i> = 27) were captured (October to March) in a semi-arid zone (Valle de Matagusanos, San Juan, Argentina) and grouped into three relevant reproductive periods: pre-reproductive (PrR), reproductive (R), and post-reproductive (PsR). Significant differences in plasma testosterone were found among these periods, highest during R than in PsR. A significant positive correlation between plasma testosterone and TLC/ALC ratio was also observed. Plasma testosterone has a significant positive correlation only with solar irradiation, but not with the other variables. In PrR and R, ARs distribution was cytoplasmic and nuclear, shifting to only cytoplasmic in PsR. These results highlight the close correspondence between plasma testosterone, Leydig cell histology and activity, environmental factors, and ARs distribution, resulting in a synchronization that allows males of <i>L. cuyanus</i> to coordinate their reproductive cycle with the most favorable environmental conditions, probably for mating and birth of offspring.</p>","PeriodicalId":15711,"journal":{"name":"Journal of experimental zoology. Part A, Ecological and integrative physiology","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139900014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Daniela Miloch, Nicolas R. Cecchetto, Julián N. Lescano, Gerardo C. Leynaud, María Gabriela Perotti
Changes in environmental temperature may induce variations in thermal tolerance and sensitivity in ectotherm organisms. These variations generate plastic responses that can be analyzed by examining their Thermal Performance Curves (TPCs). Additionally, some performance traits, like locomotion, could be affected by other factors such as biological interactions (e.g., predator–prey interaction). Here, we evaluate if the risk of predation modifies TPCs in Mendoza four-eyed frog (Pleurodema nebulosum, Burmeister, 1861) and Guayapa's four-eyed frog (Pleurodema guayapae, Barrio, 1964), two amphibian species that occur in ephemeral ponds in arid environments. We measured thermal tolerances and maximum swimming velocity at six different temperatures in tadpoles under three situations: control, exposure to predator chemical cues, and exposure to conspecific alarm cues. TPCs were fitted using General Additive Mixed Models. We found that curves of tadpoles at risk of predation differed from those of control mainly in thermal sensitivity parameters. Our work confirms the importance of biotic interactions have in thermal physiology.
{"title":"Is thermal sensitivity affected by predation risk? A case study in tadpoles from ephemeral environments","authors":"Daniela Miloch, Nicolas R. Cecchetto, Julián N. Lescano, Gerardo C. Leynaud, María Gabriela Perotti","doi":"10.1002/jez.2793","DOIUrl":"10.1002/jez.2793","url":null,"abstract":"<p>Changes in environmental temperature may induce variations in thermal tolerance and sensitivity in ectotherm organisms. These variations generate plastic responses that can be analyzed by examining their Thermal Performance Curves (TPCs). Additionally, some performance traits, like locomotion, could be affected by other factors such as biological interactions (e.g., predator–prey interaction). Here, we evaluate if the risk of predation modifies TPCs in Mendoza four-eyed frog (<i>Pleurodema nebulosum</i>, Burmeister, 1861) and Guayapa's four-eyed frog (<i>Pleurodema guayapae</i>, Barrio, 1964), two amphibian species that occur in ephemeral ponds in arid environments. We measured thermal tolerances and maximum swimming velocity at six different temperatures in tadpoles under three situations: control, exposure to predator chemical cues, and exposure to conspecific alarm cues. TPCs were fitted using General Additive Mixed Models. We found that curves of tadpoles at risk of predation differed from those of control mainly in thermal sensitivity parameters. Our work confirms the importance of biotic interactions have in thermal physiology.</p>","PeriodicalId":15711,"journal":{"name":"Journal of experimental zoology. Part A, Ecological and integrative physiology","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139735400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Japanese eel (Anguilla japonica) is a commercially important fish species in Asia. Understanding factors like photoperiod, temperature, and lunar cycles is crucial for successful aquaculture and managing its reproduction. Melatonin and dopamine (DA) are essential for regulating reproduction in vertebrates, including fish. This study investigated the effects of melatonin and DA on the reproductive system of mature male Japanese eels to better understand reproductive regulation in fish. To clarify the effects of these hormones on sexual maturation in eels, a critical stage in the reproductive process, sexual maturation was induced by injecting human chorionic gonadotropin, which stimulates the production of sex hormones. To check the effect of melatonin and DA on sexual maturation, DA, melatonin, and DA + domperidone were intraperitoneally injected into fish from each group (six per treatment) at a dose of 1 mg/kg body weight. The fish were then examined using quantitative RT-PCR by comparing the messenger RNA level of reproduction-related genes (gonadotropin releasing hormone 1; gnrh1, gonadotropin releasing hormone 2; gnrh2, follicle stimulating hormone; fshβ, luteinizing hormone; lhβ and DA receptor 2b; d2b), involved in the gonadotropic axis in eels, to those that received a control injection. The results indicate significant differences in the expression levels of gnrh1, gnrh2 and d2b in the brain and d2b, fshβ, lhβ in the pituitary at different stages of sexual maturation. Melatonin appears to enhance the production of sex gonadotropins, whereas DA inhibits them. These findings suggest an interaction between melatonin and DA in regulating reproduction in Japanese eels.
日本鳗鱼(Anguilla japonica)是亚洲的一种重要商业鱼类。了解光周期、温度和月经周期等因素对成功养殖和管理其繁殖至关重要。褪黑激素和多巴胺(DA)对调节脊椎动物(包括鱼类)的繁殖至关重要。本研究调查了褪黑激素和多巴胺对成熟雄性日本鳗鱼生殖系统的影响,以更好地了解鱼类的生殖调节。性成熟是鳗鱼生殖过程中的一个关键阶段,为了明确这些激素对鳗鱼性成熟的影响,研究人员通过注射人类绒毛膜促性腺激素来诱导鳗鱼的性成熟。为了检测褪黑素和 DA 对性成熟的影响,以 1 毫克/千克体重的剂量向每组鱼腹腔注射 DA、褪黑素和 DA + 多潘立酮(每组 6 条)。然后使用定量 RT-PCR 技术,比较鳗鱼生殖相关基因(促性腺激素释放激素 1;gnrh1、促性腺激素释放激素 2;gnrh2、促卵泡激素;fshβ、黄体生成素;lhβ 和 DA 受体 2b;d2b)与对照组的信使 RNA 水平。结果表明,在性成熟的不同阶段,gnrh1、gnrh2和d2b在大脑中的表达水平以及d2b、fshβ、lhβ在垂体中的表达水平存在明显差异。褪黑激素似乎能促进促性腺激素的产生,而DA则会抑制它们。这些研究结果表明,褪黑激素和DA在调节日本鳗鱼的繁殖过程中存在相互作用。
{"title":"Effects of dopamine and melatonin treatment on the expression of the genes associated with artificially induced sexual maturation in Japanese eel, Anguilla japonica","authors":"Jun-Hwan Byun, Ji-Yeon Hyeon, Sachithra Amarin Hettiarachchi, Shingo Udagawa, Angka Mahardini, Jong-Myoung Kim, Sung-Pyo Hur, Akihiro Takemura","doi":"10.1002/jez.2788","DOIUrl":"10.1002/jez.2788","url":null,"abstract":"<p>Japanese eel (<i>Anguilla japonica</i>) is a commercially important fish species in Asia. Understanding factors like photoperiod, temperature, and lunar cycles is crucial for successful aquaculture and managing its reproduction. Melatonin and dopamine (DA) are essential for regulating reproduction in vertebrates, including fish. This study investigated the effects of melatonin and DA on the reproductive system of mature male Japanese eels to better understand reproductive regulation in fish. To clarify the effects of these hormones on sexual maturation in eels, a critical stage in the reproductive process, sexual maturation was induced by injecting human chorionic gonadotropin, which stimulates the production of sex hormones. To check the effect of melatonin and DA on sexual maturation, DA, melatonin, and DA + domperidone were intraperitoneally injected into fish from each group (six per treatment) at a dose of 1 mg/kg body weight. The fish were then examined using quantitative RT-PCR by comparing the messenger RNA level of reproduction-related genes (gonadotropin releasing hormone 1; <i>gnrh1</i>, gonadotropin releasing hormone 2; <i>gnrh2</i>, follicle stimulating hormone; <i>fshβ</i>, luteinizing hormone; <i>lhβ</i> and DA receptor 2b; <i>d2b</i>), involved in the gonadotropic axis in eels, to those that received a control injection. The results indicate significant differences in the expression levels of <i>gnrh1</i>, <i>gnrh2</i> and <i>d2b</i> in the brain and <i>d2b</i>, <i>fshβ</i>, <i>lhβ</i> in the pituitary at different stages of sexual maturation. Melatonin appears to enhance the production of sex gonadotropins, whereas DA inhibits them. These findings suggest an interaction between melatonin and DA in regulating reproduction in Japanese eels.</p>","PeriodicalId":15711,"journal":{"name":"Journal of experimental zoology. Part A, Ecological and integrative physiology","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139706870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ongoing climate change is increasing the frequency and intensity of extreme temperature events. Unlike the gradual increase on average environmental temperatures, these short-term and unpredictable temperature extremes impact population dynamics of ectotherms through their effect on individual survival. While previous research has predominantly focused on the survival rate of terrestrial embryos under acute heat stress, less attention has been dedicated to the nonlethal effects of ecologically realistic timing and magnitude of temperature extremes on aquatic embryos. In this study, we investigated the influence of the timing and magnitude of current and projected temperature extremes on embryonic life history traits and hatchling behavior in the alpine newt, Ichthyosaura alpestris. Using a factorial experiment under controlled laboratory conditions, we exposed 3- or 10-day-old embryos to different regimes of extreme temperatures for 3 days. Our results show that exposure to different extreme temperature regimes led to a shortened embryonic development time and an increase in hatchling length, while not significantly affecting embryonic survival. The duration of development was sensitive to the timing of temperature extremes, as early exposure accelerated embryo development. Exposure to temperature extremes during embryonic development heightened the exploratory activity of hatched larvae. We conclude that the timing and magnitude of ecologically realistic temperature extremes during embryogenesis have nonlethal effects on life history and behavioral traits. This suggests that species' vulnerability to climate change might be determined by other ecophysiological traits beyond embryonic thermal tolerance in temperate pond-breeding amphibians.
{"title":"Sensitivity of amphibian embryos to timing and magnitude of present and future thermal extremes","authors":"Valentína Oborová, Monika Šugerková, Lumír Gvoždík","doi":"10.1002/jez.2791","DOIUrl":"10.1002/jez.2791","url":null,"abstract":"<p>Ongoing climate change is increasing the frequency and intensity of extreme temperature events. Unlike the gradual increase on average environmental temperatures, these short-term and unpredictable temperature extremes impact population dynamics of ectotherms through their effect on individual survival. While previous research has predominantly focused on the survival rate of terrestrial embryos under acute heat stress, less attention has been dedicated to the nonlethal effects of ecologically realistic timing and magnitude of temperature extremes on aquatic embryos. In this study, we investigated the influence of the timing and magnitude of current and projected temperature extremes on embryonic life history traits and hatchling behavior in the alpine newt, <i>Ichthyosaura alpestris</i>. Using a factorial experiment under controlled laboratory conditions, we exposed 3- or 10-day-old embryos to different regimes of extreme temperatures for 3 days. Our results show that exposure to different extreme temperature regimes led to a shortened embryonic development time and an increase in hatchling length, while not significantly affecting embryonic survival. The duration of development was sensitive to the timing of temperature extremes, as early exposure accelerated embryo development. Exposure to temperature extremes during embryonic development heightened the exploratory activity of hatched larvae. We conclude that the timing and magnitude of ecologically realistic temperature extremes during embryogenesis have nonlethal effects on life history and behavioral traits. This suggests that species' vulnerability to climate change might be determined by other ecophysiological traits beyond embryonic thermal tolerance in temperate pond-breeding amphibians.</p>","PeriodicalId":15711,"journal":{"name":"Journal of experimental zoology. Part A, Ecological and integrative physiology","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jez.2791","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139702670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aurelia F. T. Strauß, Lies Bosma, Marcel E. Visser, Barbara Helm
Artificial light at night (ALAN) widely affects wildlife by blurring light-dark differences, including transitions such as sunrise and sunset, thereby affecting regulation of diel rhythms. As a result, activity onsets in many wild diurnal songbirds advance under ALAN. From chronobiological studies, it is known that the direction and strength of the response to light depends on when during the night exposure takes place. However, these experiments are mostly done under continuous light conditions, when animals have free-running rhythms. It remains unclear whether phase-dependence also holds in entrained, wild songbirds; i.e., does the effect of ALAN on activity patterns differ between exposure in the morning compared to the evening? This information is essential to assess the effects of mitigation measures by limiting ALAN to selected times of the night. We exposed incubating great tits (Parus major) inside the nest-box to 4 h of dim light, of which 1 h overlapped with dawn before sunrise or dusk after sunset. We found a small advancing effect of morning-light on activity onset and of evening-light on offset compared to dark controls but not vice versa. Breeding success and chick condition were unaffected by the light treatments. However, light-treated females had lower weights 9–18 days after the end of the treatment compared to the controls, independent of whether ALAN occurred in the morning or the evening, indicating possible costs of ALAN. Despite the weak behavioral response, ALAN might have affected the females' circadian clock or physiology resulting in lower body condition.
夜间人工照明(ALAN)会模糊光暗差异,包括日出日落等过渡时间,从而影响昼夜节律的调节,对野生动物造成广泛影响。因此,许多野生昼行鸣禽的活动开始时间在 ALAN 下提前。从时间生物学研究中可以得知,对光的反应方向和强度取决于夜间照射的时间。然而,这些实验大多是在连续光照条件下进行的,此时动物有自由运行的节律。目前仍不清楚相位依赖性是否也适用于有节律的野生鸣禽;也就是说,早上和晚上照射 ALAN 对活动模式的影响是否有所不同?这些信息对于评估将 ALAN 限制在夜间特定时间段的缓解措施的效果至关重要。我们将正在巢箱中孵化的大山雀(Parus major)置于4小时的昏暗光线下,其中1小时与日出前的黎明或日落后的黄昏重叠。我们发现,与黑暗对照组相比,晨光对活动开始的影响和晚光对活动偏移的影响略有增加,但反之亦然。光照处理对繁殖成功率和雏鸟状况没有影响。然而,与对照组相比,光照处理雌鼠在光照处理结束后9-18天的体重较低,这与ALAN发生在早上还是晚上无关,这表明ALAN可能会造成损失。尽管行为反应微弱,但ALAN可能影响了雌鱼的昼夜节律或生理机能,导致体况下降。
{"title":"Short-time exposure to light at night affects incubation patterns and correlates with subsequent body weight in great tits (Parus major)","authors":"Aurelia F. T. Strauß, Lies Bosma, Marcel E. Visser, Barbara Helm","doi":"10.1002/jez.2787","DOIUrl":"10.1002/jez.2787","url":null,"abstract":"<p>Artificial light at night (ALAN) widely affects wildlife by blurring light-dark differences, including transitions such as sunrise and sunset, thereby affecting regulation of diel rhythms. As a result, activity onsets in many wild diurnal songbirds advance under ALAN. From chronobiological studies, it is known that the direction and strength of the response to light depends on when during the night exposure takes place. However, these experiments are mostly done under continuous light conditions, when animals have free-running rhythms. It remains unclear whether phase-dependence also holds in entrained, wild songbirds; i.e., does the effect of ALAN on activity patterns differ between exposure in the morning compared to the evening? This information is essential to assess the effects of mitigation measures by limiting ALAN to selected times of the night. We exposed incubating great tits (<i>Parus major</i>) inside the nest-box to 4 h of dim light, of which 1 h overlapped with dawn before sunrise or dusk after sunset. We found a small advancing effect of morning-light on activity onset and of evening-light on offset compared to dark controls but not <i>vice versa</i>. Breeding success and chick condition were unaffected by the light treatments. However, light-treated females had lower weights 9–18 days after the end of the treatment compared to the controls, independent of whether ALAN occurred in the morning or the evening, indicating possible costs of ALAN. Despite the weak behavioral response, ALAN might have affected the females' circadian clock or physiology resulting in lower body condition.</p>","PeriodicalId":15711,"journal":{"name":"Journal of experimental zoology. Part A, Ecological and integrative physiology","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jez.2787","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139702671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pablo Escribano-Álvarez, Mario G. Castro, Luis R. Pertierra, Miguel Á. Olalla-Tárraga
The extreme low humidity and temperatures in Antarctica make it one of the harsher areas for life on our planet. In a global change context, environmental barriers that prevented the arrival of alien species in Antarctica are weakening. Deception Island, one of the four active volcanoes of Antarctica, is especially vulnerable to the impacts of alien species. Geothermal areas (GA) in this Island offer unique microclimatic conditions that could differentially affect native and alien soil arthropods. Here we explore the desiccation tolerance of a native (Cryptopygus antarcticus) and an alien (Proisotoma minuta) springtail (Collembola) species to these extreme environmental conditions. GA and non-geothermal areas (NGA) were selected to evaluate intra- and interspecific variation in desiccation tolerance. Populations of P. minuta from GA had greater desiccation tolerance than populations from NGA. However, desiccation tolerance of C. antarcticus did not differ between GA and NGA. This native species had greater desiccation tolerance than the alien P. minuta, but also greater body size. Our findings show that the alien P. minuta responds differently to environmental conditions than the native C. antarcticus. Furthermore, body size may influence desiccation tolerance in these two springtail species.
南极洲湿度和温度极低,是地球上生命生存环境最恶劣的地区之一。在全球变化的背景下,阻止外来物种进入南极洲的环境屏障正在减弱。南极洲四大活火山之一的欺骗岛尤其容易受到外来物种的影响。该岛的地热区(GA)提供了独特的微气候条件,可对外来和本地土壤节肢动物产生不同影响。在此,我们探讨了一种本地(南极隐杆线虫)和一种外来(Proisotoma minuta)弹簧尾(鞘翅目)物种对这些极端环境条件的干燥耐受性。研究人员选择了地热区和非地热区(NGA)来评估干燥耐受性的种内和种间差异。地热区的 P. minuta 种群比非地热区的种群具有更强的耐干燥性。然而,南极鳕(C. antarcticus)的干燥耐受性在南美洲和北美洲之间没有差异。这种本地物种比外来的 P. minuta 具有更强的耐干燥性,但体型也更大。我们的研究结果表明,外来的 P. minuta 与本地的 C. antarcticus 对环境条件的反应不同。此外,体型可能会影响这两种春尾草的干燥耐受性。
{"title":"Intra and interspecific differences in desiccation tolerance in native and alien Antarctic springtails in geothermal grounds","authors":"Pablo Escribano-Álvarez, Mario G. Castro, Luis R. Pertierra, Miguel Á. Olalla-Tárraga","doi":"10.1002/jez.2789","DOIUrl":"10.1002/jez.2789","url":null,"abstract":"<p>The extreme low humidity and temperatures in Antarctica make it one of the harsher areas for life on our planet. In a global change context, environmental barriers that prevented the arrival of alien species in Antarctica are weakening. Deception Island, one of the four active volcanoes of Antarctica, is especially vulnerable to the impacts of alien species. Geothermal areas (GA) in this Island offer unique microclimatic conditions that could differentially affect native and alien soil arthropods. Here we explore the desiccation tolerance of a native (<i>Cryptopygus antarcticus)</i> and an alien (<i>Proisotoma minuta)</i> springtail (Collembola) species to these extreme environmental conditions. GA and non-geothermal areas (NGA) were selected to evaluate intra- and interspecific variation in desiccation tolerance. Populations of <i>P. minuta</i> from GA had greater desiccation tolerance than populations from NGA. However, desiccation tolerance of <i>C. antarcticus</i> did not differ between GA and NGA. This native species had greater desiccation tolerance than the alien <i>P. minuta</i>, but also greater body size. Our findings show that the alien <i>P. minuta</i> responds differently to environmental conditions than the native <i>C. antarcticus</i>. Furthermore, body size may influence desiccation tolerance in these two springtail species.</p>","PeriodicalId":15711,"journal":{"name":"Journal of experimental zoology. Part A, Ecological and integrative physiology","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jez.2789","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139691999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dormancy represents an investment with its own costs and benefit. Besides the advantage obtained from the avoidance of harsh environments and from the synchronization of life cycles with seasonal changes, an organism could benefit from a temporary stop in growth and reproduction. To test this hypothesis a transgenerational experiment was carried out comparing the life history traits of clonal females of Eucypris virens from resting and non-resting eggs at two different photoperiods: short day length (6:18 L:D), proxy of favorable but unpredictable late winter-spring hydroperiod, and long day length (16:8 L:D) proxy of dry predictable unfavorable season, inducing resting egg production and within-generation plasticity (WGP). Clonal females that were dormancy deprived showed the highest age at first deposition and the lowest fecundity. Dormancy seems to work as a resetting mechanism of reproduction. Transgenerational plasticity (TGP) had a bounce back pattern: the phenotype of F1 generation was influenced by cues experienced in the F0 generation but the effects of F0 exposure were not evident in the F2. TGP might be adaptive when a mother experiences some kind of seasonality or stochasticity producing both resting and nonresting eggs. A positive relationship between the number of resting eggs and the total number of eggs per females suggested the absence of trade-off between dormancy and reproduction. Both WGP and TGP increase the mother long term fitness with important consequences on population dynamics, on the way a species spread throughout space and time and might respond to climate change.
{"title":"To sleep or not to sleep: Dormancy and life history traits in Eucypris virens (Crustacea, Ostracoda)","authors":"Nicolò Bellin, Valeria Rossi","doi":"10.1002/jez.2786","DOIUrl":"10.1002/jez.2786","url":null,"abstract":"<p>Dormancy represents an investment with its own costs and benefit. Besides the advantage obtained from the avoidance of harsh environments and from the synchronization of life cycles with seasonal changes, an organism could benefit from a temporary stop in growth and reproduction. To test this hypothesis a transgenerational experiment was carried out comparing the life history traits of clonal females of <i>Eucypris virens</i> from resting and non-resting eggs at two different photoperiods: short day length (6:18 L:D), proxy of favorable but unpredictable late winter-spring hydroperiod, and long day length (16:8 L:D) proxy of dry predictable unfavorable season, inducing resting egg production and within-generation plasticity (WGP). Clonal females that were dormancy deprived showed the highest age at first deposition and the lowest fecundity. Dormancy seems to work as a resetting mechanism of reproduction. Transgenerational plasticity (TGP) had a bounce back pattern: the phenotype of F1 generation was influenced by cues experienced in the F0 generation but the effects of F0 exposure were not evident in the F2. TGP might be adaptive when a mother experiences some kind of seasonality or stochasticity producing both resting and nonresting eggs. A positive relationship between the number of resting eggs and the total number of eggs per females suggested the absence of trade-off between dormancy and reproduction. Both WGP and TGP increase the mother long term fitness with important consequences on population dynamics, on the way a species spread throughout space and time and might respond to climate change.</p>","PeriodicalId":15711,"journal":{"name":"Journal of experimental zoology. Part A, Ecological and integrative physiology","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139570636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}