Infrared color photography: selective demonstration of bacteria

A microscopic procedure employs infrared color photography to enable visualization of unstained microorganisms in natural habitats. The procedure can be used for either living or dead microorganisms; it enables visualizaion of microbial cells embedded within component materials of the habitat.     

Interocular transfer in goldfish: color easier than pattern

Goldfish were trained to monocularly discriminate different patterns that also differed in color. When tested with reversed combinations of color and pattern cues, the fish responded on the basis of pattern while using the trained eye but on the basis of color while using the untrained eye. Interhemispheric transfer of color information was therefore more effective than that of pattern.     

Insects as selective agents on plant vegetative morphology: egg mimicry reduces egg laying by butterflies

Experiments show that Heliconius butterflies are less likely to oviposit on host plants that possess eggs or egglike plant structures. These egg mimics are an unambiguous example of a plant trait evolved in response to a host-restricted group of insect herbivores.     

The developmental role of Agouti in color pattern evolution

Animal color patterns can affect fitness in the wild; however, little is known about the mechanisms that control their formation and subsequent evolution. We took advantage of two locally camouflaged populations of Peromyscus mice to show that the negative regulator of adult pigmentation, Agouti, also plays a key developmental role in color pattern evolution. Genetic and functional analyses showed that ventral-specific embryonic expression of Agouti establishes a prepattern by delaying the terminal differentiation of ventral melanocytes. Moreover, a skin-specific increase in both the level and spatial domain of Agouti expression prevents melanocyte maturation in a regionalized manner, resulting in a novel and adaptive color pattern. Thus, natural selection favors late-acting, tissue-specific changes in embryonic Agouti expression to produce large changes in adult color pattern.     

Evidence for selective advantage of pathogenic FGFR2 mutations in the male germ line

Observed mutation rates in humans appear higher in male than female gametes and often increase with paternal age. This bias, usually attributed to the accumulation of replication errors or inefficient repair processes, has been difficult to study directly. Here, we describe a sensitive method to quantify substitutions at nucleotide 755 of the fibroblast growth factor receptor 2 (FGFR2) gene in sperm. Although substitution levels increase with age, we show that even high levels originate from infrequent mutational events. We propose that these FGFR2 mutations, although harmful to embryonic development, are paradoxically enriched because they confer a selective advantage to the spermatogonial cells in which they arise.     

Deep human genealogies reveal a selective advantage to be on an expanding wave front

Since their origin, human populations have colonized the whole planet, but the demographic processes governing range expansions are mostly unknown. We analyzed the genealogy of more than one million individuals resulting from a range expansion in Quebec between 1686 and 1960 and reconstructed the spatial dynamics of the expansion. We find that a majority of the present Saguenay Lac-Saint-Jean population can be traced back to ancestors having lived directly on or close to the wave front. Ancestors located on the front contributed significantly more to the current gene pool than those from the range core, likely due to a 20% larger effective fertility of women on the wave front. This fitness component is heritable on the wave front and not in the core, implying that this life-history trait evolves during range expansions.     

广西甘蔗生产规模比较优势空间格局特征及影响因素分析

【目的】研究广西甘蔗生产规模发展形势及时空关联分布特征,为提升广西区域甘蔗产业的竞争力、推动广西甘蔗产业持续发展提供参考。【方法】利用规模比较优势指数对广西14个地级市的甘蔗生产规模比较优势进行分析,采用空间计量模型研究其时空关联分布特征,并对影响甘蔗规模比较优势的内部因素进行显著性分析。【结果】2011—2018年广西14个地级市的甘蔗规模比较优势指数均大于0,且省域整体甘蔗规模比较优势指数均大于1.10;各地级市间规模比较优势指数又具有显著差异性,呈现一轴两翼的分布局面,其中桂中和桂西较高,最大值为3.50左右;桂东偏低,数值均小于0.10,表明广西区域内甘蔗生产仍存在较大发展空间。从空间均衡性来看,2011—2018年全局Moran’s I指数均大于0.10,表明广西甘蔗生产规模比较优势存在显著为正的全局自相关性,并根据LISA集聚的结果进一步表明,高集聚区数量逐渐增加至4个,无显著相关性区域的数量由9递减至2个,整体呈现出点—带—片的空间结构特征,省域间空间集聚关联性不断增强。通过空间计量模型实证分析得出,影响因素按照显著性程度大小依次为单位面积机械化水平、产业结构指标、财政支农水平、农户人均纯收入,而单位面积劳动力对其不产生显著性影响,具有明显的空间溢出效应。【建议】依据广西各市甘蔗规模比较优势空间格局特征及因素间影响程度进行优劣互补,增强桂中甘蔗“双高”基地空间溢出效应;培养良种,有效降低农户甘蔗生产及企业加工成本,保障甘蔗产业规模化经营,从而实现甘蔗生产综合效益最大化。     

Fright Posture of the Plesiopid Fish Calloplesiops altivelis: An Example of Batesian Mimicry

When frightened by a predator, the plesiopid fish, Calloplesiops altivelis, adopts a posture and appearance that mimics the head of a noxious moray eel, Gymnothorax meleagris. Tests indicate that the mimicry is Batesian and not Müllerian. Unlike the strategy of other reef-fish prey species, which hide when threatened, the Calloplesiops's strategy is one of intimidation.     

放牧饲养对雪山草鸡屠宰性能及肉色的影响

【目的】探讨两阶段饲养模式对雪山草鸡屠宰性能及肉色的影响,为寻求适合高效生产优质鸡肉的饲养模式提供参考依据。【方法】选用高密度集约化饲养的雪山草鸡（公鸡80日龄,母鸡120日龄）,采用放牧饲养模式,分别于放养30和60d后取右侧胸肌、腿肌及腹脂样品,测定屠宰性能和肉色。【结果】放牧饲养鸡的活体重、胸肌率、腿肌率和腹脂率均略低于高密度集约化饲养组,但差异不显著（P〉0.05）;性别对雪山草鸡屠宰性能的影响较大,放牧饲养雪山草公鸡的腹脂率显著低于母鸡,但腿肌率显著高于母鸡（P〈0.01）。在肉色指标方面,胸肌和腿肌的亮度、红度均随着放养时间延长呈递增趋势,而黄度则呈递减趋势。【结论】放牧饲养可以降低雪山草鸡的腹脂率,提高屠宰性能,同时还能提高肌肉的亮度及红度,有利于改善肉色及肉品质。     

A single amino acid mutation contributes to adaptive beach mouse color pattern

Natural populations of beach mice exhibit a characteristic color pattern, relative to their mainland conspecifics, driven by natural selection for crypsis. We identified a derived, charge-changing amino acid mutation in the melanocortin-1 receptor (Mc1r) in beach mice, which decreases receptor function. In genetic crosses, allelic variation at Mc1r explains 9.8% to 36.4% of the variation in seven pigmentation traits determining color pattern. The derived Mc1r allele is present in Florida's Gulf Coast beach mice but not in Atlantic coast mice with similar light coloration, suggesting that different molecular mechanisms are responsible for convergent phenotypic evolution. Here, we link a single mutation in the coding region of a pigmentation gene to adaptive quantitative variation in the wild.     

九孔鲍选育群体生长规律的研究

为研究九孔鲍Haliotis diversicolor supertexta选育群体在工厂化养殖模式下的生长规律,从2016年5月12日—2017年6月中旬共进行一个养殖周期的养殖试验,即春季投苗(4月下旬—5月中旬),夏秋冬三季养成,翌年5月收获,采用模型拟合方法对九孔鲍群体的个体大小、生长速度和发育规律进行了研究。结果表明:在水温17.8～29.7℃、盐度30.0的养殖条件下,九孔鲍养成期壳长和体质量为幂函数关系,即W=0.1307L^{(2.9138 )},壳长和体质量的生长过程遵循von Bertalanffy生长模型,复相关系数R(2.9138 ),壳长和体质量的生长过程遵循von Bertalanffy生长模型,复相关系数R²>0.99,实测值和理论计算值比较接近;通过Beverton法推算生长模型中3个生长参数,得出壳长平均生长极限值为5.94 cm,体质量平均生长极限值为23.49 g;壳长生长方程为L_t=5.94(1-e2>0.99,实测值和理论计算值比较接近;通过Beverton法推算生长模型中3个生长参数,得出壳长平均生长极限值为5.94 cm,体质量平均生长极限值为23.49 g;壳长生长方程为L_t=5.94(1-e^{(-0.0063(t-18.7143)})),体质量生长方程为W_t=23.49(1-e(-0.0063(t-18.7143))),体质量生长方程为W_t=23.49(1-e^{(-0.0063(t-18.7143)}))(-0.0063(t-18.7143)))^{(3 )},壳长生长速度方程为dL/dt=0.0374e(3 ),壳长生长速度方程为dL/dt=0.0374e^{(-0.0063(t-18.7143)}),体质量生长速度方程为dW/dt=0.4440e(-0.0063(t-18.7143)),体质量生长速度方程为dW/dt=0.4440e^{(-0.0063(t-18.7143)})(1-e(-0.0063(t-18.7143))(1-e^{(-0.0063(t-18.7143)}))(-0.0063(t-18.7143)))²;工厂化养殖九孔鲍的生长拐点年龄为193.1 d,在拐点年龄之前壳长生长速度较快,之后较慢,而体质量在拐点年龄之前生长速度较慢,之后较快。本研究结果可为九孔鲍的工厂化养殖生产和选择育种提供理论参考。     

九孔鲍选育群体生长规律的研究

为研究九孔鲍Haliotis diversicolor supertexta选育群体在工厂化养殖模式下的生长规律,从2016年5月12日—2017年6月中旬共进行一个养殖周期的养殖试验,即春季投苗(4月下旬—5月中旬),夏秋冬三季养成,翌年5月收获,采用模型拟合方法对九孔鲍群体的个体大小、生长速度和发育规律进行了研究。结果表明:在水温17.8～29.7℃、盐度30.0的养殖条件下,九孔鲍养成期壳长和体质量为幂函数关系,即W=0.1307L~(2.9138 ),壳长和体质量的生长过程遵循von Bertalanffy生长模型,复相关系数R~2>0.99,实测值和理论计算值比较接近;通过Beverton法推算生长模型中3个生长参数,得出壳长平均生长极限值为5.94 cm,体质量平均生长极限值为23.49 g;壳长生长方程为L_t=5.94(1-e~(-0.0063(t-18.7143))),体质量生长方程为W_t=23.49(1-e~(-0.0063(t-18.7143)))~(3 ),壳长生长速度方程为dL/dt=0.0374e~(-0.0063(t-18.7143)),体质量生长速度方程为dW/dt=0.4440e~(-0.0063(t-18.7143))(1-e~(-0.0063(t-18.7143)))~2;工厂化养殖九孔鲍的生长拐点年龄为193.1 d,在拐点年龄之前壳长生长速度较快,之后较慢,而体质量在拐点年龄之前生长速度较慢,之后较快。本研究结果可为九孔鲍的工厂化养殖生产和选择育种提供理论参考。     

红壳色中华绒螯蟹仔蟹养殖方式研究

为探讨养殖方式对红壳色不同家系中华绒螯蟹Eriocheir sinensis仔蟹生长的影响,采用室内群体养殖、室内单体养殖和室外稻田养殖3种方式,比较了红壳色(A)、红壳家系中正常壳色(B)、"光合1号"(C),以及拟建立的早熟(D)、近亲早熟(E)育种家系仔蟹的生长特征。结果表明:室内群体养殖方式下,红壳色A组仔蟹的存活率为35.8%,仅与D组有显著性差异(P0.05);A组仔蟹头胸甲宽的变异系数(CV)为27%,个体大小差异较小,与其余组间有显著性差异(P0.05);A组仔蟹体质量特定生长率(SGR)为7.0%/d,各组间无显著性差异(P0.05)。室内单体养殖方式下,红壳色A组仔蟹的存活率为86.7%,显著高于B、E组(P0.05);A组仔蟹头胸甲宽的CV为52%,个体大小差异较大,与C、D组有极显著性差异(P0.01);A组仔蟹体质量SGR为5.7%/d,A组与B、C、E组仔蟹生长差异明显(P0.05)。室外稻田围隔养殖方式下,红壳色A组仔蟹的存活率为3.2%,极显著低于B、C、D组(P0.01);A组仔蟹头胸甲宽的CV为12%,极显著低于E、D组(P0.01);A组仔蟹体质量SGR最低,为8.1%/d,各组间无显著性差异(P0.05)。研究表明,室内单体养殖红壳色仔蟹能显著提高其成活率,有助于获得更多育种家系相关性状的信息。     

红壳色中华绒螯蟹仔蟹养殖方式研究

为探讨养殖方式对红壳色不同家系中华绒螯蟹Eriocheir sinensis仔蟹生长的影响,采用室内群体养殖、室内单体养殖和室外稻田养殖3种方式,比较了红壳色(A)、红壳家系中正常壳色(B)、光合1号(C),以及拟建立的早熟(D)、近亲早熟(E)育种家系仔蟹的生长特征。结果表明:室内群体养殖方式下,红壳色A组仔蟹的存活率为35.8%,仅与D组有显著性差异(P<0.05);A组仔蟹头胸甲宽的变异系数(CV)为27%,个体大小差异较小,与其余组间有显著性差异(P<0.05);A组仔蟹体质量特定生长率(SGR)为7.0%/d,各组间无显著性差异(P>0.05)。室内单体养殖方式下,红壳色A组仔蟹的存活率为86.7%,显著高于B、E组(P<0.05);A组仔蟹头胸甲宽的CV为52%,个体大小差异较大,与C、D组有极显著性差异(P<0.01);A组仔蟹体质量SGR为5.7%/d,A组与B、C、E组仔蟹生长差异明显(P<0.05)。室外稻田围隔养殖方式下,红壳色A组仔蟹的存活率为3.2%,极显著低于B、C、D组(P<0.01);A组仔蟹头胸甲宽的CV为12%,极显著低于E、D组(P<0.01);A组仔蟹体质量SGR最低,为8.1%/d,各组间无显著性差异(P>0.05)。研究表明,室内单体养殖红壳色仔蟹能显著提高其成活率,有助于获得更多育种家系相关性状的信息。     

The compleat angler: aggressive mimicry in an antennariid anglerfish

A case of aggressive mimicry is described in which an anglerfish of the genus Antennarius (order Lophiiformes) utilizes a lure that mimics a small fish. The lure provides not only a highly attractive visual cue but presumably also a low-frequency pressure stimulus for potential prey with a minimum of energy expenditure.     

Pitch memory: an advantage for the left-handed

In an auditory or musical task, subjects made pitch recognition judgments when the tones to be compared were separated by a sequence of interpolated tones. The left-handed subjects performed significantly better than the right-handed and also had a significantly higher variance. Further analysis showed that the superior performance was attributable largely to the left-handed subjects with mixed hand preference.