Seasonal acclimatization of metabolism in Eurasian tree sparrows (Passer montanus)

Acclimatization to winter conditions is an essential prerequisite for survival of small passerines of the northern temperate zone. Changes in photoperiod, ambient temperature and food availability trigger seasonal acclimatization in physiology and behavior of many birds. In the present study, seasonal adjustments in several physiological, hormonal, and biochemical markers were examined in wild-captured Eurasian tree sparrows (Passer montanus) from the Heilongjiang Province in China. In winter sparrows had higher body mass and basal metabolic rate (BMR). Consistently, the dry mass of liver, heart, gizzard, small intestine, large intestine and total digestive tract were higher in winter than in that in summer. The contents of mitochondrial protein in liver, and state-4 respiration and cytochrome c oxidase (COX) activity in liver and muscle increased significantly in winter. Circulating level of serum triiodothyronine (T₃) was significantly higher in winter than in summer. Together, these data suggest that tree sparrows mainly coped with cold by enhancing thermogenic capacities through increased organ masses and heightened activity of respiratory enzymes activities. The results support the view that prominent winter increases in BMR are manifestations of winter acclimatization in tree sparrows and that seasonal variation in metabolism in sparrows is similar to that in other small temperate-wintering birds.     

树麻雀肝脏和肌肉产热特征的季节性变化

北温带的小型鸟类,通过增加产热来适应低温环境.基础代谢率(BMR)是内温动物能量预算的重要组成部分.本研究中我们分别在冬季和夏季测定了树麻雀(Passer montanus)的BMR、肝脏和肌肉的线粒体蛋白含量、线粒体呼吸及细胞色素C氧化酶(COX)活力及血清中甲状腺激素(T4)及甲状腺原氨酸(T3)含量的变化.结果显示:树麻雀的体重和BMR冬季显著高于夏季;肝脏的线粒体呼吸、肝脏和肌肉的COX活力冬季较高,夏季较低;血清T3浓度冬季明显高于夏季.这些结果表明:在野外条件下,肝脏和肌肉在细胞水平产热能力的提高和血清T3含量的增加,是树麻雀抵御冬季寒冷的重要方式之一.     

成都市区麻雀夜宿规律初步观察

2002年10月～2003年10月,对成都市区内一观察点麻雀的夜宿规律进行了观察。发现麻雀夜宿归巢时间、高峰时间、结束时间和清晨飞离时间有较强的规律,认为这是麻雀的生物节律决定的。     

树麻雀代谢率和器官重量在光周期驯化中的变化

为探讨光周期对树麻雀代谢产热和代谢器官变化的影响,对成年树麻雀 Passer montanus 进行温度为25℃、两种光周期16 L:8 D(LD组)和8 L:16 D(SD组)4周的气候箱驯化后,测定其体重、基础代谢率(BMR)、体脂和水分含量,以及各器官、组织的鲜重和干重.结果 显示,SD组麻雀BMR显著大于LD组,作为代谢活性器官的消化道显著增生是其BMR显著增加的主要原因之一;麻雀通过增加体重和能量储备物脂肪来实现对较长黑暗环境的适应是其成功的生存策略.SD组麻雀体重的显著增加和水分含量显著降低,说明短光照的刺激引起麻雀能量储备的增加和代谢活性器官消化道增生.光周期驯化的结果验证了中心限制假说,即麻雀体内存在着与BMR相关的代谢机器,中心器官(消化道)是改变麻雀BMR的基础之一.     

Pair copulation frequency correlates with female reproductive performance in Tree Sparrows Passer montanus

In socially monogamous birds, males benefit from frequent copulations with their partner if this increases their paternity in the brood. By soliciting and accepting copulation attempts, female birds can control pair copulation frequencies. Engaging in copulations can be costly by taking up time and by increasing the risks of predation and pathogen transmission. Current hypotheses propose that high pair-copulation frequencies may compensate for these costs by providing females with direct benefits that can result in higher reproductive success. In this study, I examine in a Tree Sparrow population the prediction that high pair-copulation frequencies are associated with better female reproductive performance. The results show that clutch sizes laid were positively correlated with the pair-copulation frequency. The length of the incubation period was negatively correlated and, as expected, the number of fledglings was positively correlated with pair-copulation frequency. The results are consistent with current hypotheses for the evolution of frequent pair copulations and provide one of the few evidences for a positive relation between pair-copulation frequency and female reproductive performance. This study also suggests that within-pair copulation frequency could be an early expression of the pairs' reproductive ability and might signal their phenotypic quality.     

Isolation of polymorphic microsatellite markers in the tree sparrow (Passer montanus)

To enable the study of the population genetics of the tree sparrow (Passer montanus), which is distributed in many islands of Japan, nine polymorphic microsatellite loci were isolated from 32 individuals. The number of alleles per locus ranged from 2 to 17, and observed heterozygosities ranged from 0.1250 to 0.9375. In eight of the nine loci, the heterozygosities were not significantly different from those expected from Hardy-Weinberg equilibrium. Cross-species amplification in the russet sparrow (P. rutilans) was successful with all primer sets, which were highly polymorphic, suggesting these markers are useful for the population genetics of genus Passer.     

树麻雀代谢率和器官重量在温度驯化中表型的可塑性变化

为探讨温度对树麻雀基础代谢和代谢器官的表型可塑性变化,以人工气候箱驯养4周的光周期为12L:12D、温度为5℃(实验组)和25℃(对照组)的两组成年树麻雀为研究对象,测定其体重、基础代谢率(BMR)、体脂和水分含量以及各器官、组织的湿重和干重.结果实验组麻雀的BMR显著升高,体脂含量和水分含量以及体重均没有显著变化;肝脏重量和肾脏湿重显著增加,干重增加不显著;总消化管干重、小肠干重、直肠湿重和干重显著降低(P<0.01),胃湿重增加显著(P<0.05).由此提示:环境温度改变引起麻雀各器官结构和功能能力相应的可塑性的调整变化,器官能耗总量的增加很可能是引起BMR升高的主要原因,是麻雀器官能耗与功能能力、摄食量与消化率乃至个体适合度价与环境因素进行能量预算的结果.     

北京市麻雀体质水平沿城市化梯度的变化

麻雀是城市和乡村均有分布的鸟类物种.快速的城市化正在使城市麻雀的栖息地和食物资源大量减少.以北京市为例,研究了麻雀的体质水平沿城市化梯度的变化,以期为我国城市化过程中的鸟类保护提供参考.研究结果表明城市高层楼房居民区、低层楼房居民区以及大学校园中麻雀的体质指数显著低于郊区环境,而城市公园和平房居民区麻雀的体质水平则与郊区环境的差异较小.随采样点城市化水平的增加,麻雀的体质水平呈下降趋势,高度城市化的环境导致麻雀的体质水平下降.在城市化过程中,增加城市公园的数量及居民区的植被覆盖量可为麻雀等鸟类提供必要的生活资源,从而实现城市化过程中的生物多样性保护.     

Cd~(2+)处理后麻雀脑组织中糖皮质激素受体和盐皮质激素受体表达变化

目的检测在Cd~(2+)处理后糖皮质激素受体(GR)和盐皮质激素受体(MR)在麻雀Passer montanus脑组织中的表达变化。方法 6只麻雀随机分成2组,每组3只。处理组饮水中添加500μg·L~(-1)Cd~(2+),对照组不添加。用Clustal W2将麻雀的GR和MR氨基酸序列与其他物种氨基酸序列进行相似性比对分析。采用Real-time PCR检测基础水平下麻雀各组织中GR和MR基因的表达水平。Cd~(2+)处理后,测定GR和MR基因在脑组织中的表达变化。结果麻雀与斑胸草雀Taeniopygia guttata和原鸡Gallus gallus的GR和MR氨基酸序列的相似性大于90%;GR和MR基因在麻雀肝脏、肠、心脏、眼球、脑、肺、肌肉、肾脏和性腺9个组织中均有表达;Cd~(2+)处理后,处理组脑组织中GR和MR mRNA表达水平均上调,且显著高于对照组(P0.05)。结论 GR和MR在麻雀各组织中广泛表达;推测GR和MR基因在Cd~(2+)的应激反应中具有重要作用,具体作用还有待于进一步论证,同时该研究为野外工作提供了一定的实验依据。     

四川盆地的陆地岛屿效应——基于树麻雀的形态变异

以树麻雀Passer montanus为研究对象,采集四川盆地及周边地区558个样本的7项形态指标,控制纬度因子的偏相关分析表明,树麻雀的体质量、尾长、跗跖长与海拔极显著正相关(P0.01),体长与海拔显著正相关(P0.05);控制海拔因子的偏相关分析表明,树麻雀的体质量、翅长与纬度极显著正相关(P0.01)。按照海拔将树麻雀分为3组:四川盆地(海拔平均值:484.25 m,海拔范围:219~725 m)、华中平原(海拔平均值:250.70 m,海拔范围:46~784 m)、盆地周边山地(海拔平均值:2 260.42 m,海拔范围:807~4 472 m)。单因素方差分析表明:3个树麻雀种群的体质量、翅长、尾长、跗跖长之间的差异有高度统计学意义(P0.01),盆地周边山地树麻雀种群的体质量显著或极显著大于四川盆地及华中平原(P0.05或P0.01)。综上,树麻雀体型随海拔升高而显著增大,说明树麻雀的形态变异与海拔变化密切相关,符合贝格曼定律。同时,四川盆地与华中平原树麻雀种群在体质量、体长、尾长、翅长、跗跖长、嘴峰、嘴裂上的差异均无统计学意义(P0.05),未能体现出四川盆地的陆地岛屿效应。     

Field observation of predation on adult lepidopterans by the tree sparrow Passer montanus saturatus

Many studies have examined defensive strategies of adult lepidopterans against bird predation. However, detailed field observations that describe how lepidopterans are hunted by wild birds are quite limited. I observed foraging behavior of wild tree sparrows on adult lepidopterans from May to June 2006 at Mt Yoshida, Kyoto, Japan. A total of 253 foraging attempts on at least 14 species of lepidopterans were observed. The tree sparrows attacked both resting and flying lepidopterans. When a tree sparrow approached a resting lepidopteran, the lepidopteran frequently flew to escape predation. The number of feeding attempts for resting and flying lepidopterans was 215 and 38, respectively. This result indicates that resting lepidopterans are the main target of predation by the tree sparrow. It is therefore considered that reducing the risk of detection is important for lepidopterans to avoid predation by the tree sparrow. Coloration as crypsis is probably effective in this respect.     

The diet of Eurasian Tree Sparrow Passer montanus nestlings in relation to agri-environment scheme habitats

It has been suggested by some authors that the UK agri-environment ‘wild bird seed’ option negatively impacts Tree Sparrow populations in the UK. Here we provide evidence for a change in nestling diet with increasing wild bird seed coverage and propose a possible mechanism for its negative impact on population trends.