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91.
Mate Choice and Mating Pattern in a Stream Goby of the Genus Rhinogobius   总被引:4,自引:0,他引:4  
The mate choice and mating pattern of a benthic goby Rhinogobius sp. CB (cross band type) were investigated in the Kamo River, Shikoku, Japan. During the breeding season, gravid females assumed a nuptial color and either males or females initiated a courtship display. Males preferentially courted a female of similar size to lead her to his nest, whereas females courted more frequently when they encountered a large male. Eggs in any one nest were always at the same developmental stage. Sampling data of nesting males and females indicated that, in more than half the nests, males gathered more than one female before spawning. In some nests with eggs, two or three females had spent ovaries, indicating that the eggs were laid by multiple females within a short span of time. However, a comparison between the total number of eggs which females would spawn in one nest and the number of eggs actually deposited suggested that eggs were contributed by one female in most nests. This low level of polygyny in spite of multiple female availability is attributed to a limited available spawning area of the nest.  相似文献   
92.
Nutritional risk in children is associated with food safety. This is the first study to identify the food type consumed by 6–17-year-old school-going children in Saudi Arabia. Eight permitted artificial food color additives, including Tartrazine (E102), Sunset Yellow (E110), Carmoisine (E122), Allura Red (E129), Indigo Carmine (E132), Brilliant Blue (E133), Fast Green (E143), and Black PN (E151), and two non-permitted ones, Erythrosine (E127) and Red 2G (E128), were determined using 24-h dietary recall questionnaires. Artificial color additives in 839 food products were divided into nine categories, including biscuits, cakes, chocolates, chips, ice cream, juices and drinks, candy, jelly, and chewing gum, are determined using high performance liquid chromatography and diode array detector. The results indicated a high intake of juices and drinks, ice cream, and cakes, but low consumption of chewing gum among school-going children. Among the permitted artificial food color additives, Brilliant Blue (E133) (54.1%) and Tartrazine (E102) (42.3%) were the most commonly used. Sunset Yellow (E110) in one chocolate sample, Tartrazine (E102) and Sunset Yellow (E110) in one and two juice and drink samples, respectively, and Brilliant Blue (E133) in two candy samples exceeded the permitted level. Therefore, further investigations are needed to provide insights into the possible adverse health effects of high intake of these additives in artificial food coloring on the test population are warranted.  相似文献   
93.
为了明确不同桃品种资源果实香气差异,对桃果实香气评价和品质改良提供参考,本研究利用电子鼻系统对桃品种资源果实整果香气进行测定和区分。通过PEN 3.5电子鼻系统采集74份不同品种资源桃果实芳香成分并得到了不同传感器的响应值,采用主成分(PCA)、线性判别法(LDA)和负荷加载(LO)方法分析数据。LO分析结果显示,硫化氢(W1W)、氮氧化物类(W5S)、甲烷类(W1S)、芳香成分与有机硫化物(W2W)传感器对供试桃果实香气的评价起主要作用;结合PCA和区分度值表明白花水蜜、脆保、春冠、奉罐1号、菊黄和红肉桃1号与其他供试品种资源的香气区别较大;LDA可将不同果实生育期桃较好区分,长、中、短不同果实生育期桃甲烷类和芳香成分与有机硫化物传感器响应值差异显著(P<0.05);LDA可将硬肉类型(肉质绵)与其他4种肉质类型桃(不溶质、硬溶质、软溶质和硬质)区分开,且硬肉类型与其他4种肉质类型桃甲烷类传感器响应值差异显著(P<0.05);LDA无法区分不同肉色的桃,且各传感器响应值差异不显著。结果表明,生育期长短对桃果实香气有明显影响;硬肉类型桃香气较独特;不同肉色桃香气接近。  相似文献   
94.
Sex differences in animal coloration often result from sex‐dependent regulatory mechanisms. Still, some species exhibit incomplete sexual dimorphism as females carry a rudimentary version of a costly male trait, leading to intralocus sexual conflict. The underlying physiology and condition dependence of these traits can inform why such conflicts remain unresolved. In eastern fence lizards (Sceloporus undulatus), blue iridophore badges are found in males and females, but melanin pigmentation underneath and surrounding badges is male‐exclusive. We track color saturation and area of badges across sexual maturity, and their relationship to individual quality (body condition and immunocompetence) and relevant hormones (testosterone and corticosterone). Saturation and testosterone were positively correlated in both sexes, but hormone and trait had little overlap between males and females. Saturation was correlated with body condition and immunocompetence in males but not in females. Co‐regulation by androgens may have released females from resource allocation costs of color saturation, even when in high condition. Badge area was independent of testosterone, but associated with low corticosterone in females, indicating that a nonsex hormone underlies incomplete sexual dimorphism. Given the evidence in this species for female reproductive costs associated with ornamentation, this sex‐nonspecific regulation of an honest signal may underlie intralocus sexual conflict.  相似文献   
95.
Measurement of the visual function in the tadpoles of the frog, Xenopus laevis, allows screening for blindness in live animals. The optokinetic response is a vision-based, reflexive behavior that has been observed in all vertebrates tested. Tadpole eyes are small so the tail flip response was used as alternative measure, which requires a trained technician to record the subtle response. We developed an alternative behavior assay based on the fact that tadpoles prefer to swim on the white side of a tank when placed in a tank with both black and white sides. The assay presented here is an inexpensive, simple alternative that creates a response that is easily measured. The setup consists of a tripod, webcam and nested testing tanks, readily available in most Xenopus laboratories. This article includes a movie showing the behavior of tadpoles, before and after severing the optic nerve. In order to test the function of one eye, we also include representative results of a tadpole in which each eye underwent retinal axotomy on consecutive days. Future studies could develop an automated version of this assay for testing the vision of many tadpoles at once.  相似文献   
96.
A novel acylated cyanidin 3-sambubioside-5-glucoside was isolated from the purple-violet flowers of Matthiola longipetala subsp. bicornis (Sm) P. W. Ball. (family: Brassicaceae), and determined to be cyanidin 3-O-[2-O-(2-O-(trans-feruloyl)-β-xylopyranosyl)-6-O-(trans-feruloyl)-β-glucopyranoside]-5-O-[6-O-(malonyl)-β-glucopyranoside] by chemical and spectroscopic methods. In addition, two known acylated cyanidin 3-sambubioside-5-glucosides, cyanidin 3-O-[2-O-(2-O-(trans-sinapoyl)-β-xylopyranosyl)-6-O-(trans-feruloyl)-β-glucopyranoside]-5-O-[6-O-(malonyl)-β-glucopyranoside] and cyanidin 3-O-[2-O-(β-xylopyranosyl)-6-O-(trans-feruloyl)-β-glucopyranoside]-5-O-[6-O-(malonyl)-β-glucopyranoside] were identified in the flowers.  相似文献   
97.
Abstract This paper deals with the karyotype of green peach aphid, Myzus persicae (Sulzer), with three different life cycles in different regions of China. The results showed that four types of karyotype were found in the natural populations of red form and brown form aphids. Four types of karyotype are as follows: 2n = 12 with autosomes 1, 3 translocated (T1–3); 3n = 18 normal triploid; 3n = 18 with T1–3 translocation; and 2n = 11. However, in the yellowish‐green aphids there were only two types of karyotype, normal karyotype 2n= 12 (NK) and 2n = 12 with T1–3 translocation. There was no significant difference in the relative lengths of chromosomes in 2n = 12 karyotype among different color forms and groups from different regions.  相似文献   
98.
Summary Color notations of dorsal pelage were analyzed in 451 adult subterranean mole rats, comprising 19 populations and 4 chromosomal species (2n=52, 54, 58 and 60) of the Spalax ehrenbergi superspecies in Israel. In addition, the color notations of soil samples from the collection sites were measured. In an attempt to evaluate the degree of correlation between pelage color of mole rats and the local soil color, each color was compared both macro- and microgeographically. The macrogeographic comparisons were among populations of the 4 chromosomal species, and the microgeographic comparisons were among pairs of geographically neighboring subpopulations which occur under similar climatic conditions but differ in soil type and color. The results indicate that 1. no differences in pelage color notation exist between the sexes; 2. pelage of mole rats is generally characterized by an over-all grayish color, but its shades vary regionally and locally in accordance with varying soil color; 3. a positive correlation was found between pelage and local soil colors in the macrogeographic analysis and this correlation was verified in a microgeographic comparison; 4. specimens from populations of the northern chromosomal species (2n=52, 54) mainly inhabit terra rossa and basalt soils, respectively, with reddish brown tones, and they tend to have a more reddish shade, whereas animals from the central species (2n=58), which inhabits mainly dark soils including alluvial clays, terra rossa and brown rendzina and the souther species 2n=60, which occurs mainly in light soil types such as pale rendzina, sandy loams and loess, tend to have a more yellowish shade. The general appearance of specimens from 2n=58 was dark gray while that of 2n=60 specimens was light gray; 5. mole rats living in xeric environments (particularly 2n=60, but also 2n=54) are lighter than those which live in mesic environments (2n=52, 58). The results support the conclusion that pelage color of strictly subterranean mole rats is subject to selection pressures of overground predation of disharmonious types with their background soil color. The possibility that the pelage color variation and patterns also contributes to better thermoregulation while mole rats are above ground is discussed.  相似文献   
99.
To introduce a set of genetic studies among Solomon Islanders, four tribal groups on Bougainville and Malaita Islands are described. They were observed in 1966 and 1968 by social anthropologists and biomedical scientists from Harvard University. The groups varied in habitat and way of life from fishermen living on artificial islets in a saltwater lagoon (the Lau, on Malaita) to shifting agriculturists (the Nasioi, on Bougainville, and the Kwaio and Baegu, on Malaita). The Nasioi were darker than the Malaitans and spoke a non-Austronesian rather than a Melanesian language; they were also more Westernized. Coverage of residents in designated hamlets ranged from 78% to over 95%. In all, 1,626 persons were studied: 256 Nasioi, 443 Kwaio, 442 Lau, and 485 Baegu. Genetic differences have been found between the Nasioi and the Malaitans, and between the Lau and the other Malaitans.  相似文献   
100.
Replidated experiments indicate an association between thermal tolerance of juvenile bluegill sunfish and adaptive pigmentation to background color. Bluegills exposed to black backgrounds were able to survive higher temperatures longer than those exposed to blond backgrounds, when water temperatures were raised at a rate of 0.1°C/h from 24 to 36°C. Plausible explanations are considered which involve heat radiation effectiveness (by the fish) related to the black body concept, and stress associated with adaptive pigmentation.  相似文献   
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