昆虫体色二态性的研究进展

昆虫中普遍存在性二态性,主要包括体型、体色、行为等方面的差异,而雌雄体色差异是其典型特征,一般雄性体色相对于雌性更鲜艳,这种现象的产生可能与环境对性别的选择效应或性别间的种内竞争有关,在昆虫求偶、躲避天敌、适应环境中具有重要的生物学意义。昆虫体色二态性的遗传调控机制及生理因素一直备受关注。了解体色二态性分子机制的形成,有助于深入探究两性的交配行为及种群进化过程。研究表明,性别决定基因Doublesex(Dsx)和内分泌激素均参与昆虫性二态性的调控过程,但影响体色形成的靶标基因及两者协同调控体色形成的分子机制尚不清楚。本文综述了性别决定信号通路和内分泌激素对昆虫性二态性的影响,以及两者之间的协同关系,和典型的体色二态性昆虫研究进展,以期为深入理解昆虫体色二态性的形成机制研究提供参考。

2个纯合体色品系大瓶螺的几何形态测量学研究

为了探究大瓶螺(Pomacea canaliculata)体色、性别与贝壳形态之间的关系,运用几何形态测量学方法,对来自于人工繁育的F5纯合体色品系37只深褐色个体(26♀♀,11♂♂)、34只黄色个体(14♀♀,20♂♂)贝壳的正壳口观、壳口观、壳顶观进行地标标点,获得贝壳的形态信息。运用主成分分析和典型变量分析,检测出不同体色、性别个体间的差异。通过各个标点对于相对扭曲的贡献率,探究其形态变化趋势。主成分分析结果表明,不同体色个体的贝壳形态存在着明显差异,正壳口观较壳口观及壳顶观更能体现贝壳差异;而不同体色的贝壳差异均不及相同体色不同性别个体间贝壳的差异。典型变量分析结果通过普氏距离和马氏距离得以反映,所有组别间的马氏距离均有显著性差异,而普氏距离仅在壳顶观的深褐色和黄色雌螺间以及壳顶观的深褐色和黄色雄螺间无显著差异;对正壳口观各标点对相对扭曲的贡献率分析表明,贝壳形态的变化主要集中在壳口上半部,支持不同体色和性别的大瓶螺在贝壳形态上存在显著差异的结论。发掘大瓶螺中所存在的这些差异对探究不同体色个体的适应性差异提供了重要参考,也表明几何形态测量学可以作为贝壳形态研究的有效方法应用于贝类形态学和种群分析等研究中。

雌、雄草原田鼠外周骨骼肌肌球蛋白重链的表达(英文)

已往的研究对于实验室应用的各种啮齿类动物,如大鼠和小鼠骨骼肌蛋白表达的特性已有报道。然而,至今不清楚其它啮齿类动物如野生鼠骨骼肌蛋白的表达或性双态性的特征,而这些野生鼠的行为学、形态学及生理学特点均已有报道。已知骨骼肌的肌球蛋白重链( MHC)成分与其功能特性有关。我们研究了草原田鼠的肱三头肌、胫骨前肌、腓肠肌和比目鱼肌MHC蛋白表达的性别特性。应用SDS聚丙烯酰胺凝胶电泳法测定MHCⅠ型、Ⅱa型、Ⅱd/x和Ⅱb型的蛋白表达相对含量。结果表明:与雌鼠相比,雄鼠的比目鱼肌湿重较大,胫骨前肌的MHCⅡa蛋白量表达较高。未见骨骼肌重量及MHC蛋白表达含量在雌雄鼠间的性别差异。血中睾酮的浓度差异可能不影响外周骨骼肌蛋白的表达特性。然而,与过去在大鼠、兔和小鼠中的已报道的结果相比,草原田鼠骨骼肌MHC的表达显示了更多异质性。推测这可能与草原田鼠和其它小型哺乳类动物生存的自然环境和功能需要有关。

雌雄燕雀鸣唱相关核团HVc和RA的突触比较

在超微结构水平上比较了雌雄燕雀前脑两个鸣唱相关核团—上纹状体腹侧尾部（thehyperstriatumventrale,parscaudale,HVc）和古纹状体栎核（therobustnucleusofthearchistriatum,RA）神经毡中的突触类型和数目.发现在突触总数、Grayl型实触数、棘突触数等方面存在着明显的性二态性,雄鸟突触数明显多于雌鸟。

Flotation performances of polymorphic pyrrhotite

The floatability of different crystalline structures of pyrrhotite(monoclinic and hexagonal) was studied.It is shown that the floatability of monoclinic and hexagonal has obvious difference,and that the flotation recovery of monoclinic pyrrhotite is larger than that of hexagonal pyrrhotite using different collectors.When butyl dithiophosphate is used as the collector,the recovery is larger than that by sodium butyl xanthate and sodium diethyl dithiocarbamate.At the pH values ranging from 6 to 9,monoclinic pyrrhotite can be floated well,and the flotation recovery is higher than 90%.Monoclinic and hexagonal pyrrhotites are more easily activated by Cu2+ in acidic conditions than in alkaline conditions.But Cu2+ cannot activate hexagonal pyrrhotite using sodium diethyldithiocarbamate as the collector.By the measurement of contact angle,it is indicated that monoclinic and hexagonal pyrrhotites float well and are easily activated by Cu2+ when dithiophosphate is used as the collector.Using sodium diethyl dithiocarbamate as a collector,the relationship between potential and pH range for pyrrhotite flotation is established.At pH 5,the optimal potential range for flotation of monoclinic pyrrhotite is about 125-580 mV(vs SHE),with the maximum flotation occurring at about 350 mV(vs SHE);the optimal potential range for flotation of hexagonal pyrrhotite is 200?580 mV(vs SHE),with the maximum flotation occurring at about 300 mV(vs SHE).

Optimality Conditions for Static Programming with Generalized Convexity

The definitions of generalized pseudoconvex,generalized quasiconvex and its stri ctly generalized convexity were presented for the static programming at locally star -shaped set using the concept of right-upper derivative and the concept of sub linear. The sufficient and necessary conditions of the static programming were d erived in terms of a generalized Lemma in this paper. The results obtained are u seful for the further study on the duality of static programming and cover many already known conditions.

Sexual dimorphism of the electrophysiological properties of the projection neurons in the robust nucleus of the arcopallium in adult zebra finches

Objective To observe the sexual differences in electrophysiological properties of neurons in the robust nucleus of the arcopallium （RA） in adult zebra finches, and to provide the direct electrophysiological evidence for the sexual dimorphism of birdsong. Methods Whole-cell recording was used to record the spontaneous action potential firing rates from RA projection neurons in acute brain slices. Results The projection neurons of RA in male birds fired spontaneously at 10 Hz or above, while in female birds, the frequency was significantly lower, and even no firings could be detected. Conclusion There is a sexual difference in electrophysiological properties of projection neurons in RA, which may result from the difference in the levels of steroid hormones in birds.

Sexual differences and sex ratios of dioecious plants under stressful environments

Dioecious plants exhibit sexual dimorphism in both sexual features(reproductive organs)and secondary sex characteristics(vegetative traits).Sexual differences in secondary traits,including morphological,physiological and ecological characters,have been commonly associated with trade-offs between the cost of reproduction and other plant functions.Such trade-offs may be modified by environmental stressors,although there is evidence that sexually dimorphic responses to stress do not always exist in all plant species.When sexual dimorphism exists,sexually different responses appear to depend on the species and stress types.Yet,further studies on dioecious plant species are needed to allow the generalization of stress effects on males and females.Additionally,sexual dimorphism may influence the frequency and distribution of the sexes along environmental gradients,likely causing niche differentiation and spatial segregation of sexes.At the present,the causes and mechanisms governing sex ratio biases are poorly understood.This review aims to discuss sex-specific responses and sex ratio biases occurring under adverse conditions,which will advance our knowledge of sexually dimorphic responses to environmental stressors.

Polyploidization and sexual dimorphism of floral traits in a subdioecious population of Dasiphora glabra

Aims Sexual dimorphism is a common trait in plants with sex separation,which could influence female and male functions differently.In a subdioecious population of Dasiphora glabra on the Qinghai-Tibet Plateau,we investigated sexual dimorphism of floral traits and their effects on pollinator visitation,pollen flow and seed production.We also examined differences in genome size of hermaphroditic and dioecious plants.Methods We examined sexual dimorphism in flower number,flower size,and pollen and ovule production in a subdioecious population of D.glabra.We compared pollinator visitation,pollen dispersal and seed production between sexes.We also examined the genome size of three sex morphs using flow cytometry.Important Findings The number of hermaphroditic plants was significantly more than that of male and female plants,and dioecious plants accounted for ca.40%in the study population.Hermaphroditic plants produced significantly more flowers than male and female plants.Flower size of male flowers was significantly larger than that of female and hermaphroditic flowers.Male flowers did not produce more pollen grains than hermaphroditic flowers,but female flowers produced more ovules than hermaphroditic flowers.Flies were the most frequent flower visitors and preferred large flowers,but their movements between flowers did not show any preference to large flowers.Simulated pollen flows suggested that effective pollen transfer was generally low for both hermaphroditic and male flowers,corresponding to the low seed set of naturally pollinated flowers.DNA contents of male and female plants were ca.four times than those of hermaphroditic plants.These results suggest male and female individuals have undergone polyploidy events and thus are not compatible with hermaphroditic individuals.Sexual dimorphism in floral traits in relation to pollination of dioecious plants might show an advantage in female and male functions,but this advantage is masked largely by low effectiveness of pollen transfer.

The Bargmann Symmetry Constraint and Binary Nonlinearization of the Super Dirac Systems

An explicit Bargmann symmetry constraint is computed and its associated binary nonlinearization of Lax pairs is carried out for the super Dirac systems. Under the obtained symmetry constraint, the n-th flow of the super Dirac hierarchy is decomposed into two super finite-diinensional integrable Hamiltonian systems, defined over the super- symmetry manifold R^4N{2N with the corresponding dynamical variables x and tn. The integrals of motion required for Liouville integrability are explicitly given.