我国东南部地区夏季两种雀形目鸟类的代谢产热特征及其体温调节

采用封闭式流体压力呼吸计,分别在5-35℃和5-40℃的环境温度范围内测定了白头鹎(Pycnonotussinensis)和丝光椋鸟(Sturnussericeus)的代谢率、热传导和体温等指标,探讨其代谢产热特征。结果显示:在环境温度(Ta)为5-35℃时,白头鹎的体温基本维持恒定,平均温度为40.3±0.1℃,热中性区为26.6-32.8℃,基础代谢率为73.10±4.11mlO2/h,是体重预期值的79%;Ta在5-26℃范围内,代谢率(MR)与Ta呈负相关,回归方程为:MR[mlO2/h]=265.37-7.24Ta(℃);Ta在5-30℃范围内,热传导值最低且基本保持恒定,平均为0.24±0.01mlO2/g·h·℃,是体重预期值的126%。丝光椋鸟的热中性区为27.6-34.5℃,平均体温为40.5±0.1℃(5-40℃),基础代谢率为160.64±9.20mlO2/h,是体重预期值的90%;最低热传导为0.16±0.05mlO2/g·h·℃,是体重预期值的129%。在5-25℃范围内,MR与Ta的回归方程为:MR[mlO2/h]=377.96-7.88Ta(℃)。白头鹎和丝光椋鸟的基本生物学特征为:较高的体温,热传导和上临界温度,较宽的热中性区和较低的代谢率,符合南方小型鸟类的代谢特征.     

The phylogeny of the world's bulbuls (Pycnonotidae) inferred using a supermatrix approach

The bulbuls comprise an ecologically important group of frugivorous, seed‐dispersing birds found in Asia and Africa. Although several studies have examined the phylogenetic relationships of subsets of bulbul species, a comprehensive phylogeny of the family Pycnonotidae has hitherto been lacking. We used publicly available sequences generated from previous phylogenetic studies, augmented by new sequences from several unstudied taxa, to create a supermatrix from which to infer the phylogeny of the family. In all, we compared 121 of the 130 bulbul species. Our tree supports the monophyly of the family and comprises an exclusively African and a predominantly Asian clade. Several genera were found not to be monophyletic and we suggest taxonomic changes to provide a more accurate classification based on phylogeny.     

温度与光周期对白头鹎体质量、能量收支和消化道形态的影响

温度与光周期是环境季节性变化的最直接表现因子及时间变化指示标志,对动物的形态、生理及行为产生重要的影响.本文以白头鹎为研究对象,探讨了不同温度与光周期对其体质量、能量收支和消化道形态的影响,分析了能量收支与消化道形态特征的关系.将28只白头鹎(12雄16雌)分为4组:暖温长光组(30℃,16 L8 D;3雄4雌)、暖温短光组(30 ℃,8 L16 D;3雄4雌)、低温长光组(10 ℃,16 L8 D;3雄4雌)和低温短光组(10 ℃,8 L16 D;3雄4雌).结果表明: 低温与短光照可促进白头鹎的体质量、摄入能及同化能明显增加,同时温度与光周期的交互作用对白头鹎的摄入能及同化能影响显著.低温条件下,胃、小肠、直肠及总消化道的湿质量及干质量明显增加.残差分析表明,小肠与总消化道的长度及干质量与摄入能和同化能显著相关.表明低温与短光照下白头鹎通过增加体质量、能量摄入和改变消化道形态来应对严酷的环境条件.     

Mitochondrial DNA suggests multiple colonizations of central Philippine islands (Boracay,Negros) by the sedentary Philippine bulbul Hypsipetes philippinus guimarasensis (Aves)

In this study, we have used fragments of three mitochondrial genes (Control Region, CR; transfer RNA for methionine, tRNA‐Met; NADH dehydrogenase subunit 2, ND2 for a total of 1066 bp) to reconstruct the phylogeographic history of the endemic Philippine bulbul (Hypsipetes philippinus) at the scale of the central area of the Philippine archipelago. The study includes two of the five recognized subspecies (guimarasensis and mindorensis), 7 populations and 58 individuals. Multiple phylogenetic and network analyses support the existence of two reciprocally monophyletic maternal lineages corresponding to the two named subspecies. Molecular clock estimates indicate that the split between the two subspecies is consistent with the Pleistocene geological history of the archipelago. Patterns of relationships within guimarasensis are biogeographically less clear. Here, a combination of vicariance and dispersal needs to be invoked to reconcile the molecular data with the geographical origin of samples. In particular, the two islands Boracay and Negros host mitochondrial lineages that do not form monophyletic clusters. Our genetic data suggest multiple independent colonization events for these locations.     

The influence of ethanol on feeding in the frugivorous yellow-vented bulbul (Pycnonotus xanthopygos)

The sugars in fleshy fruits provide a rich source of energy to frugivorous animals. However, these carbohydrates also serve as a substrate for alcoholic fermentation by yeasts, ethanol being the main by-product of this process. Ethanol ingestion via frugivory thus occurs in a diverse assemblage of invertebrate and vertebrate taxa, including numerous species of birds. We tested the roles of ethanol as an odor cue for resource location by adult yellow-vented bulbuls (Pycnonotus xanthopygos) and as a possible appetite stimulant in feeding trials with artificial food. We hypothesized (1) that the odor of ethanol does not serve as a food-locating cue in diurnal frugivorous passerine birds, and predicted that the choice of food source and the mass of food eaten by such birds will not be influenced by the odor of ethanol. We further hypothesized (2) that food intake in passerine birds is affected by ingestion of ethanol according to its concentration [EtOH], and predicted that food intake will follow a bell-shaped curve in relation to [EtOH]. In accord with hypothesis (1) and its prediction, we found that the odor of ethanol did not affect food preferences, in either ethanol-naïve or ethanol-experienced yellow-vented bulbuls, when presented at concentrations found in naturally ripe fruit (0.0–1.0%); this suggests that the odor of ethanol is not a food-locating cue for the bulbuls. Hypothesis (2) was partially supported, namely at low [EtOH] (0–3%), food intake was constant and at high [EtOH] (3%) food intake decreased, following only the right half of the predicted bell-shaped response. Ethanol-naïve birds showed no preference towards any [EtOH] presented in two-way choice trials. However, daily food intake in ethanol-experienced bulbuls in single option trials decreased by an average of 36% when the artificial food contained the highest tested concentration of ethanol (3.0%). We suggest that decreasing food intake when food ethanol concentration is relatively high may be a means of avoiding intoxication and is related to the ethanol-metabolizing ability of the bird.     

Preferences and apparent digestibilities of sugars by fruit damaging birds in Japan

Gray starlings Sturnus cineraceus, azure-winged magpies Cyanopica cyana and brown-eared bulbuls Hypsipetes amaurotis are among the main bird pests in commercial fruit orchards in central Japan. Recently Brugger & Nelms (1991) suggested that developing high-sucrose fruit cultivars could reduce crop damage, because some pest birds lack the enzyme sucrase and can develop an aversion to sucrose. Preferences for, and digestibilities of, the monosaccharides glucose and fructose and the disaccharide sucrose by these pests species were therefore studied to assess whether this idea would be applicable in central Japan. Gray starlings and brown-eared bulbuls were able to detect glucose, fructose, a mixture of glucose and fructose, and sucrose at a concentration of 12% w/v. Azure-winged magpies also detected glucose and fructose, but failed to detect sucrose at the same concentration. In pairwise preference trials gray starlings and azure-winged magpies selected the monosaccharides over sucrose, but brown-eared bulbuls did not. To estimate the digestibility of the sugars the apparent assimilated mass coefficient, AMC*, was calculated for each species eating each sugar by measuring intake and faecal output. Monosaccharides had mean AMC*s of 0.77, 0.96 and 0.92 when consumed by gray starlings, azure-winged magpies and brown-earned bulbuls respectively. AMC* values for sucrose were 0.82 and 0.49 for brown-eared bulbuls and azure-winged magpies respectively, but gray starlings were shown to be unable to digest sucrose. As AMC* values varied from 0.75 to 0.97, consumption rates of sugars increased as digestibility decreased. Although increasing sucrose contents of commercial fruits may deter sucrase-deficient birds such as gray starlings from depredating fruits, it may also lead to increased crop damage by species such as the azure-winged magpie and brown-eared bulbul which may have to consume more of the less digestible fruit in order to meet their energy requirements.     

The breeding biology of the White-spectacled Bulbul,Pycnonotus xanthopygos,at the northwestern edge of its distribution range

The White-spectacled Bulbul, Pycnonotus xanthopygos, is an abundant and possibly invasive species in Turkey, where it has gradually expanded its distribution and breeding range in both western and southeastern directions. This study focused on its breeding biology, which is still poorly known. The breeding activity extends from February until September. The preferred nesting areas are mainly gardens and maquis groves, where 24 different nesting tree species have been identified. The clutch size is 3.3 ± 0.8 eggs per pair, nesting success 68%, hatching success 94%, fledgling success 95%, and overall breeding success 89%. While nesting success differs significantly between the years, we found no significant differences in hatching, fledging, and overall breeding success between the years studied. Despite favourable climatic conditions in the Mediterranean region, the species makes only one brood per year in a relatively extended breeding season extending over seven months, and has a relatively a high reproduction rate per nest.     

白头鹎肝脏和肌肉冬夏两季的代谢产热特征比较

动物能量代谢的生理生态特征与物种的分布和丰富度密切相关,基础代谢率(basal metabolic rate,BMR)是恒温动物维持正常生理机能的最小产热速率,是内温动物能量预算的重要组成部分.该文以白头鹎(Pycnonotus sinensis)为研究对象,分别在冬季和夏季测定了白头鹎的体重、BMR、肝脏和肌肉的线粒体蛋白质含量、线粒体呼吸及细胞色素C氧化酶(cytochrome c oxidase,COX)活力及血清中甲状腺素(T4)及三碘甲腺原氨酸(T3)含量的变化,从细胞和酶学水平上解释白头鹎基础产热的季节适应规律.耗氧量采用封闭式流体压力呼吸测定仪测定,肝脏和肌肉的线粒体状态4呼吸及COX活力采用铂氧电极-溶氧仪测定.结果显示:白头鹎的体重和BMR冬季显著高于夏季;肝脏和肌肉的线粒体呼吸,以及肝脏和肌肉的COX活力冬季明显高于夏季;血清T3浓度冬季较高,夏季较低.这些结果表明:在野外自然条件下,肝脏和肌肉在细胞水平产热能力的提高和血清T3含量的增加是白头鸭BMR增加的细胞学机制之一,同时是白头鹎抵御冬季寒冷的一种重要方式.     

The nutritional significance of a winter‐flowering succulent for opportunistic avian nectarivores

The winter‐flowering succulent Aloe marlothii provides nectar for many opportunistic avian nectarivores in southern African savannas. We assessed the importance of A. marlothii nectar sugar for opportunistic nectarivores by analysing temporal changes in stable carbon isotope ratios (δ¹³C) in the tissues of birds in Suikerbosrand Nature Reserve, South Africa. The blood of the 11 most common non‐granivorous opportunistic nectarivores at our site was enriched in ¹³C by 3.4 ± 1.5‰ during the flowering period of A. marlothii, reflecting the enriched crassulacean acid metabolism (CAM) isotopic signature of nectar (?12.6 ± 0.5‰). This relatively small contribution of A. marlothii nectar to assimilated carbon in whole blood contrasted with that of exhaled CO₂ in African Red‐eyed Bulbuls Pycnonotus nigricans and Cape White‐eyes Zosterops capensis. In both these species, the δ¹³C of breath samples was significantly enriched compared with blood and feathers, and closely resembled that of the nectar, revealing combustion of ingested nectar rather than assimilation. Although our analysis was complicated by the presence of C₄ grasses, whose δ¹³C values are similar to those of CAM photosynthesizers, when considered with previously published feeding observations our data reveal that opportunistic nectarivores feeding on A. marlothii nectar obtain a relatively small fraction of their assimilated carbon, but most of their metabolized carbon, from this seasonally available carbohydrate food resource. Because the δ¹³C values of insects associated with C₃ plants also became enriched during the flowering season, some insect‐eating opportunistic nectarivores may have assimilated A. marlothii carbon indirectly from insects. This study highlights the importance of understanding isotopic routing when assessing the nutritional significance of specific dietary items to consumer communities.     

Role of birds in dissemination of the thread blight disease caused byCylindrobasidium argenteum

The thread blight disease of broad leaved trees caused byCylindrobasidium argenteum occurred in laurel forests over 20 yr old after clear cutting in Kyushu. Finding fruit bodies of the causal fungus was possible but very difficult in the forests. In inoculation tests using spores and infected branches harvested in the forests, we succeeded in transmission only with branches. In the forests, the disease is transmitted almost entirely by contact with infected branches. During 1989 to 1992 we found four brown-eared bulbul nests containing branches infected with the disease. In one nest, mycelia of the fungus had been transmitted to the host tree. The occurrence of the disease in forests over 20-yr-old was considered to be due to the nesting of birds in trees which provided the necessary height and closed environment.