Rapid evolution of a geographic cline in size in an introduced fly

The introduction and rapid spread of Drosophila subobscura in the New World two decades ago provide an opportunity to determine the predictability and rate of evolution of a geographic cline. In ancestral Old World populations, wing length increases clinally with latitude. In North American populations, no wing length cline was detected one decade after the introduction. After two decades, however, a cline has evolved and largely converged on the ancestral cline. The rate of morphological evolution on a continental scale is very fast, relative even to rates measured within local populations. Nevertheless, different wing sections dominate the New versus Old World clines. Thus, the evolution of geographic variation in wing length has been predictable, but the means by which the cline is achieved is contingent.     

沟胫天牛亚科后翅翅脉特征在系统分类学上的意义

比较研究了沟胫天牛亚科１８族１５２种的后翅翅脉,结果表明,后翅翅脉特征在该亚科不同类群间具有显著的差异,可归纳为３种基本脉型,即翅脉共柄型、基柄残留 型和翅脉基干减退型。后翅翅脉特征具有族级、属级分类学意义,对阐述沟胫天牛亚科不同类群间的亲缘关系和系统演化具有重要价值。     

Cuticular protein gene LmACP8 is involved in wing morphogenesis in the migratory locust,Locusta migratoria

Cuticular proteins(CPs) are major components of the insect cuticle-associated organs such as integument and wings, although the importance of CPs for wing development and function in hemimetabolous insects remains understudied. In the present study, a wing cuticular protein LmACP8 was identified from Locusta migratoria, which belongs to the RR-2 subfamily of cuticular protein RR consensus(CPR) chitin-binding proteins. LmACP8 was mainly expressed in the wing pads and showed high expression levels before ecdysis of third-, fourth-, and fifth-instar nymphs, with its encoded protein located in the procuticle of wing pads and adult wings. Depletion of LmACP8 by RNA interference markedly reduced the amount of its protein, which consequently caused abnormal wing morphogenesis in the transition from nymph to adult of L. migratoria. We further demonstrated that the abnormal morphogenesis was caused by severe damage of the endocuticle in the wings. LmACP8 was suppressed by 20-hydroxyecdysone(20 E) in vivo, however, its expression was significantly up-regulated after knocking down the hormone receptor gene LmHR39. Thus, the LmACP8 that is negatively regulated by the LmHR39-mediated 20 E signaling pathway is involved in wing development during the nymph to adult transition.     

蚜虫翅型分化研究进展

综述了蚜虫生物学特性以及蚜虫翅型分化的系统发育学分布和影响因子,分析了蚜虫翅型分化的进化特点,并对其翅型分化研究进行了展望。     

The aerodynamics of free-flight maneuvers in Drosophila

Using three-dimensional infrared high-speed video, we captured the wing and body kinematics of free-flying fruit flies as they performed rapid flight maneuvers. We then "replayed" the wing kinematics on a dynamically scaled robotic model to measure the aerodynamic forces produced by the wings. The results show that a fly generates rapid turns with surprisingly subtle modifications in wing motion, which nonetheless generate sufficient torque for the fly to rotate its body through each turn. The magnitude and time course of the torque and body motion during rapid turns indicate that inertia, not friction, dominates the flight dynamics of insects.     

Bat flight generates complex aerodynamic tracks

The flapping flight of animals generates an aerodynamic footprint as a time-varying vortex wake in which the rate of momentum change represents the aerodynamic force. We showed that the wakes of a small bat species differ from those of birds in some important respects. In our bats, each wing generated its own vortex loop. Also, at moderate and high flight speeds, the circulation on the outer (hand) wing and the arm wing differed in sign during the upstroke, resulting in negative lift on the hand wing and positive lift on the arm wing. Our interpretations of the unsteady aerodynamic performance and function of membranous-winged, flapping flight should change modeling strategies for the study of equivalent natural and engineered flying devices.     

基于有限元分析的机翼损伤评估的建模

以某型轻型飞机机翼结构为例,给出了在 Ansys 中建立机翼损伤模型的过程。首先通过结构模型建立以及对其进行约束分析、载荷分析和结果修正,实现了机翼结构的"杆一板"模型。在此基础上,根据损伤的位置和特征,建立了机翼局部损伤评估有限元模型。     

中国梨木虱翅型变化及其影响因素初探

对中国梨木虱不同月份和不同光周期下的翅型变化进行研究.结果表明,梨木虱翅型随月份发生明显变化,5—9月为短翅型,10月至次年4月为长翅型.恒温20℃条件下,短光周期(9 h光/15 h暗、8 h光/16 h暗)可诱导产生长翅型,而长光周期(12 h光/12 h暗,10 h光/14 h暗)可诱导产生短翅型.短光周期下长翅...     

四种虎凤蝶翅面斑纹特征及鳞片的超微结构

比较了中华虎凤蝶、太白虎凤蝶、乌苏里虎凤蝶和日本虎凤蝶成虫翅面斑纹特征及鳞片超微结构。前翅外缘黄色斑,后翅外缘半月斑、亚外缘红色斑、亚外缘黑色斑、中室黑带及前翅外缘形状和后翅尾突长度等特征在种间有明显差别,是种鉴定的重要依据。鳞片按其形状和结构可分为４种类型,后翅外缘处的青色鳞片具金属光泽,为结构色,其余各色鳞片的结构相同,为色素色。四种虎凤蝶的鳞片超微结构无明显差异。     

果蝇小翅·残翅基因作用探究

[目的]探究果蝇小翅与残翅基因间的作用关系。[方法]利用果蝇2种不同翅型的突变体进行杂交,找出小翅、残翅基因同时存在个体,观察其翅的表型,同时对翅的分离比进行推测,研究果蝇小翅与残翅基因间的作用关系。[结果]正反交果蝇的表现型不相同。果蝇的小翅品系和残翅品系的正交组合的杂交后代F1雌、雄全部为长翅,而反交组合的雌蝇为长翅,雄蝇为小翅。F2的翅型有长翅、小翅、残翅3种,小翅、残翅基因同时存在的个体表型为残翅,并且翅型分离比均为长翅：小翅：残翅=3：3：2。[结论]残翅基因对小翅基因具有遮盖作用。     

Surface-skimming stoneflies: a possible intermediate stage in insect flight evolution

Insect wings appear to have evolved from gills used by aquatic forms for ventilation and swimming, yet the nature of intermediate stages remains a mystery. Here a form of nonflying aerodynamic locomotion used by aquatic insects is described, called surface skimming, in which thrust is provided by wing flapping while continuous contact with the water removes the need for total aerodynamic weight support. Stoneflies surface skim with wing areas and muscle power output severely reduced, which indicates that surface skimming could have been an effective form of locomotion for ancestral aquatic insects with small protowings and low muscle power output.     

Morphogenetic effects of 6-azauracil and 6-azauridine

When 6-azauracil and 6-azauridine are fed to larvae of the tu(w) rc strain of Drosophila melano-gaster which has the normal wing shape, adults hatch with shortened, obliquely truncated wings. This wing shape resembles that of the mutant dumpy. On the other hand, administration of these drugs to the mutant dumpy strain increases wing length, and flies with normal wings are obtained.     

白桦雌花发育的形态相关

以20年生白桦的雌花序为材料,研究了白桦雌花发育时序特征和形态相关性,测量了不同发育时期种子的纵径、横径、横径(含种翅)及花柱长。纵径、横径和横径(含种翅)随着发育进程呈现逐渐增长趋势。减数分裂之前的4月底至5月中旬期间,纵径与横径处于缓慢增长状态,5月15日到5月28日,减数分裂和配子体形成期间二者增长幅度较大,5月29日以后又趋于平稳。花柱的长度变化不大,纵横径比值呈缓慢平稳增长趋势,而花柱长与纵径的比值变化则较大,呈迅速下降趋势。横径(含翅)与横径相比,其增长幅度在5月21日之后更大,说明种翅在此期间增长较快。白桦花发育各时期的形态特征较明显,因此,根据花外部形态变化大致判断其生殖发育状态是可行的,能在一定程度上利于相关研究的适时取材问题。     

翼铲式马铃薯挖掘铲有限元分析与试验

为提高丘陵山地及小地块的马铃薯收获效率,设计了一种结构轻便、碎土性能良好与手扶拖拉机相配套的翼铲式马铃薯挖掘铲,应用Pro/E软件创建翼铲三维模型,通过ANSYS进行有限元分析,并开展了田间试验.结果表明:翼铲安全系数为3.745,满足预期设计要求;田间试验结果表明,薯、土分离效果好,明薯率为97.5%,伤薯率为1.5%,技术指标符合马铃薯收获规范要求.     

Evolution of shape by multiple regulatory changes to a growth gene

The genetic changes responsible for morphological differences between species are largely unidentified. Such changes can involve modifications of growth that are relevant to understanding evolution, development, and disease. We identified a gene that induces male-specific wing size and shape differences between Nasonia wasp species. Fine-scale mapping and in situ hybridization reveal that changes in at least three regions (two strictly in noncoding sequence) around the gene unpaired-like (upd-like) cause changes in spatial and temporal expression of upd-like in the developing wing and corresponding changes in wing width. Upd-like shows homology to the Drosophila unpaired gene, a well-studied signaling protein that regulates cell proliferation and differentiation. Our results indicate how multiple changes in the regulation of upd-like are involved in microevolution of morphological and sex-specific differences between species.     

Evolution of the gene network underlying wing polyphenism in ants

Wing polyphenism in ants evolved once, 125 million years ago, and has been a key to their amazing evolutionary success. We characterized the expression of several genes within the network underlying the wing primordia of reproductive (winged) and sterile (wingless) ant castes. We show that the expression of several genes within the network is conserved in the winged castes of four ant species, whereas points of interruption within the network in the wingless castes are evolutionarily labile. The simultaneous evolutionary lability and conservation of the network underlying wing development in ants may have played an important role in the morphological diversification of this group and may be a general feature of polyphenic development and evolution in plants and animals.     

Extrusion of cells with inappropriate Dpp signaling from Drosophila wing disc epithelia

Decapentaplegic (Dpp) is a signaling molecule that controls growth and patterning of the developing Drosophila wing. Mutant cells lacking Dpp signal transduction have been shown to activate c-Jun amino-terminal kinase (JNK)-dependent apoptosis and to be lost from the wing disc epithelium. These observations have led to the hypothesis that Dpp promotes cell survival by preventing apoptosis. Here, we show that in the absence of JNK-dependent apoptosis, mutant cells lacking Dpp signal transduction can survive; however, they are still lost from the wing disc epithelium. This loss correlates with extensive cytoskeletal changes followed by basal epithelial extrusion. We propose that Dpp promotes cell survival within disc epithelia by affecting cytoskeletal organization.     

马铃薯田间迁飞蚜种类及发生时期调查初报

采用黄板诱捕的方法,查得青海东部马铃薯田间的迁飞蚜隶属３科,１２属,１９种,其中已知的主要种类有桃蚜、酸模蚜等１４种。据观察,该地区薯田的迁飞蚜出现于５月下列至９月上旬,不同地区的迁飞期随海拔升高而相应推迟,虫种数也趋于减少。     

Leading-edge vortex improves lift in slow-flying bats

Staying aloft when hovering and flying slowly is demanding. According to quasi-steady-state aerodynamic theory, slow-flying vertebrates should not be able to generate enough lift to remain aloft. Therefore, unsteady aerodynamic mechanisms to enhance lift production have been proposed. Using digital particle image velocimetry, we showed that a small nectar-feeding bat is able to increase lift by as much as 40% using attached leading-edge vortices (LEVs) during slow forward flight, resulting in a maximum lift coefficient of 4.8. The airflow passing over the LEV reattaches behind the LEV smoothly to the wing, despite the exceptionally large local angles of attack and wing camber. Our results show that the use of unsteady aerodynamic mechanisms in flapping flight is not limited to insects but is also used by larger and heavier animals.