Origin and development of the wings of Lepidoptera

Summary In Lepidoptera (Pieris rapae) the imaginal wing discs originate by a thickening of the thoracic pleural hypodermis at the close of embryonic life. The tracheoles originate in the endotracheal layer at the close of the first moult and become functional at the close of second moult. They grow very rapidly and reach their limit of penetration in the larval wing at end of third moult. At the beginning of fifth instar they become less abundant degenerate and disappear by absorption in the pupal wing.The permanent system of tracheoles evaginate from the wing trachea in the prepupal stage and become functional during pupal life. The wing passes to the exterior by a drawing back of the hypodermal wing sac. The rapid expansion of the wing causes the withdrawal of hypodermis. The sharp division into larval and pupal stages applies more particularly to the exterior of the body as they follow one another after successive moults, the internal development is a continuous series of transformations, between which there is no sharp line of demarcation. Yet on the whole the form of larva, pupa and imago are kept distinct in adaptation to their separate environments and habits.

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Zusammenfassung Die imaginalen Flügelscheiben nehmen bei Schmetterlingen (Pieris rapae) ihren Ursprung ans einer Verdickung der pleuralen Thoraxhypodermis am Schlusse des Embryonallebens. Die Tracheolen nehmen ihren Ursprung in der endotrachealen Schicht am Schlusse der ersten Häutung und beginnen am Schlusse der zweiten zu funktionieren. Sie wachsen sehr rasch und erreichen die Grenze ihres Eindringens in den Larvenflügel am Ende der dritten Häutung. Am Beginne der fünften werden sie dagegen weniger reichlich, degenerieren und verschwinden durch Absorption im Flügel der Puppe.Das bleibende Tracheolensystem stülpt sich aus der Flügeltrachea im Vorpuppenstadium aus und tritt während des Puppenlebens in Funktion. Der Flügel gelangt durch ein Zurückziehen des hypodermalen Flügelsackes an die Außenwelt. Die rapide Ausdehnung des Flügels veranlaßt das Zurückweichen der Hypodermis. Die scharfe Teilung in Larven- und Puppenstadium findet ihre Anwendung mehr auf das Körperäußere, da das eine auf das andre nach successiven Häutungen folgt. Die innere Entwicklung ist eine kontinuierliche Reihe von Formveränderungen, zwischen denen keine scharfe Trennungslinie existiert. Im ganzen aber bleiben die Larven-, Puppen- und Imagoform je nach Anpassung an ihre verschiedene Umgebung und ihre verschiedenen Lebensgewohnheiten streng getrennt.

     

基于蛾翅翅脉特征的夜蛾昆虫数字化分类研究 （鳞翅目：夜蛾科）

本文以夜蛾昆虫为研究对象,利用蛾右前翅翅脉特征对7种夜蛾昆虫进行数字化分类研究。首先,利用软件tpsDig2提取蛾翅翅室周围翅脉交点作为标记点;再利用普世叠加方法消除非形状因素等信息,计算出每一个翅脉交点与初始交点的距离作为特征参数;最后,利用方差分析和逐步判别分析验证各项特征参数对7种夜蛾进行分类的可行性、有效性和重要性。研究结果表明,筛选出5项特征参数可以作为分类变量,其作用大小依次为:(Dis_(16)、Dis_(17))(Dis_(13)、Dis_(15))Dis_(12),原始判别和交叉判别结果的正确率分别为96.2%和96.2%。这说明蛾翅翅脉的特征参数可用于蛾类昆虫的数字化分类鉴定。     

蛾翅数学形态特征用于夜蛾分类和鉴定的可行性研究

摘要: 为探讨蛾翅数学形态特征(MMC)在夜蛾科分类鉴定中的可行性, 本文利用数字化技术获得和处理昆虫图像, 对鳞翅目夜蛾科6种夜蛾的右前翅提取矩形度、 延长度、 叶状性、 偏心率、 球状性、 似圆度和不变矩Hu1、 Hu2等13项与大小尺度和方向均无关的数学形态特征, 并利用方差分析、 逐步判别分析和聚类分析等方法研究了各项数学形态特征在昆虫分类上作为分类特征的可行性、 可靠性和重要性, 并且从数学形态学角度对夜蛾科6个种的亲缘关系进行了分析。分析结果认为矩形度和延长度2个形态特征对这6种夜蛾的分类鉴定没有显著意义, 从而筛选出11个形态特征作为分类变量, 它们的作用大小依次为： （偏心率、 Hu5、 Hu7）＞Hu2＞似圆度＞球状性＞Hu3＞（叶状性、 Hu1、 Hu6）＞Hu4。利用蛾翅的这些特征参数成功地实现了对夜蛾科6种夜蛾的分类鉴定, 基于这些特征参数的6种夜蛾的亲缘关系远近与基于传统形态学的系统进化观点相同。研究表明蛾翅数学形态特征可应用于蛾类昆虫的快速鉴定, 为未来逐步实现蛾类昆虫的自动识别奠定了基础。     

Culture of honeybee organs: Development of a new medium and the importance of tracheation

Summary A culture system for honeybeen fat body and ovary was developed that supported optimal levels of protein synthesis by the explanted tissues. Abdominal body wall preparations of honeybee workers and queens, with adhering fat body, and ovaries of egg-laying queens were incubated in a culture medium designed to match honeybee hemolymph composition as closely as possible. Incorporation of [³H]eucine into soluble tissue proteins was measured. The new medium makes possible rates of tracer incorporation into fat body proteins that are up to three times higher than other media tested. When the tracheal system of the organs was let intact and open to the air during incubation, protein synthesis increased 17-fold (fat body) or 15-fold (ovary) as compared to preparations without open tracheas. After explantation into the medium, labeled proteins were synthesized at a highly variable rate for 10 h, probably due to wound response, and at a constant rate for the next 60 h. In contrast, ovarian protein synthesis occurred at a constant rate for at least 20 h and showed no wound response. The rate of tracer incorporation into fat body proteins was 3.2 times greater in tissues from the queen. This culture system is therefore suitable for a variety of investigations in honeybeen development and reproduction. These studies were supported by grants from the Deutsche Forschungsgemeinschaft, a Senior Scientist Award from the Alexander v. Humboldt Foundation for H. H. Hagedorn, and a fellowship from the Deutscher Akademischer Austauschdienst for H. H. Kaatz.     

Hormonal basis of adult eclosion in the gypsy moth (Lepidoptera: Lymantriidae)

Eclosion hormone was found to control the stereotypic adult eclosion behaviour of Lymantria dispar, the gypsy moth. A bioassay for hormonal activity was developed utilizing pharate adult females, and comparisons were made with the Manduca wing assay. The distribution of eclosion hormone activity was confined to the central nervous system tissues including the protocerebrum, corpora allata/corpora cardiaca complex, thoracic and the last abdominal ganglion. Haemolymph ecdysteroid titres were determined daily throughout pupal-adult development, and the peak activity period was found in 3–4 day pupae. Eclosion hormone activity in the brain and corpora allata/corpora cardiaca complex started to increase when the ecdysteroid titre dropped to background levels. Eclosion hormone in the brain peaked in the pharate adult stage, was released in the haemolymph 1 h prior to eclosion, which coincides with the depletion of activity in the retrocerebral complex, and fell to undetectable levels after the adult emerged.     

Salivary glands and salivary pumps in adult Nymphalidae (Lepidoptera)

The salivary glands and salivary pumps were investigated by means of dissection and serial semithin sections in order to expose the anatomy and histology of Nymphalidae in relation to feeding ecology. The paired salivary glands are tubular, they begin in the head, and extend through the thorax into the abdomen. The epithelium is a unicellular layer consisting of a single cell type. Despite the uniform composition, each salivary gland can be divided into five anatomically and histologically distinct regions. The bulbous end region of the gland lies within the abdomen and is composed of highly prismatic glandular cells with large vacuoles in their cell bodies. The tubular secretion region extends into the thorax where it forms large loops running backward and forward. It is composed of glandular cells that lack large vacuoles. The salivary duct lies in the thorax and also shows a looped formation but is composed of flat epithelial cells. The salivary reservoir begins in the prothorax and reaches the head. Its cells are hemispherical and bulge out into the large lumen of the tube. In the head the outlet tube connects the left and right halves of the salivary gland, and its epithelial cells are flat. The salivary pump lies in the head ventral to the sucking pump and leads directly into the food canal of the proboscis. It is not part of the salivary gland but is derived from the salivarium. Both the thin cuticle of the roof of the salivary pump and the thick bottom are ventrally arched. Paired muscles extend from the hypopharyngeal ridges and obviously serve as dilators for the pump. A functional interpretation of the salivary pump suggests that when not in use, the dilators are not contracted and the pump is tightly closed due to its own elasticity. When the dilator muscles repeatedly contract, the saliva is forced forward into the food canal of the proboscis. The salivary gland anatomy was found to be similar to other Lepidoptera. Furthermore, the histology of the salivary glands is identical in all examined butterflies, even in the species which exhibit specialized pollen-feeding behavior.     

How the pterosaur got its wings

Throughout the evolutionary history of life, only three vertebrate lineages took to the air by acquiring a body plan suitable for powered flight: birds, bats, and pterosaurs. Because pterosaurs were the earliest vertebrate lineage capable of powered flight and included the largest volant animal in the history of the earth, understanding how they evolved their flight apparatus, the wing, is an important issue in evolutionary biology. Herein, I speculate on the potential basis of pterosaur wing evolution using recent advances in the developmental biology of flying and non‐flying vertebrates. The most significant morphological features of pterosaur wings are: (i) a disproportionately elongated fourth finger, and (ii) a wing membrane called the brachiopatagium, which stretches from the posterior surface of the arm and elongated fourth finger to the anterior surface of the leg. At limb‐forming stages of pterosaur embryos, the zone of polarizing activity (ZPA) cells, from which the fourth finger eventually differentiates, could up‐regulate, restrict, and prolong expression of 5′‐located Homeobox D (Hoxd) genes (e.g. Hoxd11, Hoxd12, and Hoxd13) around the ZPA through pterosaur‐specific exploitation of sonic hedgehog (SHH) signalling. 5′Hoxd genes could then influence downstream bone morphogenetic protein (BMP) signalling to facilitate chondrocyte proliferation in long bones. Potential expression of Fgf10 and Tbx3 in the primordium of the brachiopatagium formed posterior to the forelimb bud might also facilitate elongation of the phalanges of the fourth finger. To establish the flight‐adapted musculoskeletal morphology shared by all volant vertebrates, pterosaurs probably underwent regulatory changes in the expression of genes controlling forelimb and pectoral girdle musculoskeletal development (e.g. Tbx5), as well as certain changes in the mode of cell–cell interactions between muscular and connective tissues in the early phase of their evolution. Developmental data now accumulating for extant vertebrate taxa could be helpful in understanding the cellular and molecular mechanisms of body‐plan evolution in extinct vertebrates as well as extant vertebrates with unique morphology whose embryonic materials are hard to obtain.     

樟巢螟成虫的求偶及交配行为

在光周期14 L∶〖KG-*2〗10 D、温度（27±1） ℃、相对湿度（60±10）%的室内条件下,研究了樟巢螟成虫的求偶及交配行为.结果表明：樟巢螟雌蛾在光期不求偶,进入暗期后少数个体开始求偶,暗期5 h求偶个体百分率明显增加,暗期6～7 h达求偶高峰期;不同日龄雌蛾的求偶率不同,以2～3日龄雌蛾较高,高峰期求偶率达70%以上;樟巢螟雌雄蛾的交配行为依时间顺序可分为求偶和交配2个过程;雌雄蛾间的交配主要发生在暗期5～9 h,交配高峰期在暗期6～7 h,与雌蛾的求偶高峰期一致;樟巢螟雌蛾一生只交配1次;雌雄比1∶1处理的雌蛾交配率显著低于雌雄比1:2处理,但前者的交配持续时间明显高于后者.     

Stiffness of desiccating insect wings

The stiffness of insect wings is typically determined through experimental measurements. Such experiments are performed on wings removed from insects. However, the wings are subject to desiccation which typically leads to an increase in their stiffness. Although this effect of desiccation is well known, a comprehensive study of the rate of change in stiffness of desiccating insect wings would be a significant aid in planning experiments as well as interpreting data from such experiments. This communication presents a comprehensive experimental analysis of the change in mass and stiffness of gradually desiccating forewings of Painted Lady butterflies (Vanessa?cardui). Mass and stiffness of the forewings of five butterflies were simultaneously measured every 10 min over a 24 h period. The averaged results show that wing mass declined exponentially by 21.1% over this time period with a time constant of 9.8 h, while wing stiffness increased linearly by 46.2% at a rate of 23.4 μN mm(-1) h(-1). For the forewings of a single butterfly, the experiment was performed over a period of 1 week, and the results show that wing mass declined exponentially by 52.2% with a time constant of 30.2 h until it reached a steady-state level of 2.00 mg, while wing stiffness increased exponentially by 90.7% until it reached a steady-state level of 1.70 mN mm(-1).     

Comparative functional morphology of the wings of Diptera

Wings of representative species of the order Diptera were compared with a simple model structure in which corrugated spars diverge from a V-shaped leading edge spar. Both develop torsion and camber when subjected to aerodynamic loads, forming a propeller shape. Both the leading edge and the cubitus of flies' wings twist basally, allowing camber to be set up as the media hinges up or down at the arculus. Three different wing types were identified: stiff wings possessing two or three main spars; and wings capable of ventral flexion. In wings possessing only two spars, found mainly in the Nematocera, control of camber is achieved largely by the use of cross veins. Wing control and flight are generally imprecise. The third spar, found in most Brachycera, in the Syrphidae and in the Conopidae controls camber and helps support a broader wing. Finer control of camber is exerted by marginal cross veins, and these insects generally have precise, darting flight. Ventral flexion mechanisms are found in the Simuliidae, the Stratiomyiidae, and widely in the Schizophora. Control of ventral flexion, which occurs at the end of the downstroke, allows fast, unpredictable manoeuvres. Functional similarities indicate either phylogenetic relationship or convergence.     

Homology and function in the wings of Heteroptera

Abstract. The homology of veins and other wing characters in Heteroptera is reviewed in the light of palaeontology and new functional studies. A cladogram is given for the higher taxa of Hemiptera. It is probable that the vannus is an autapomorphy of Auchenorrhyncha+Heteropteroidea; that the leading edge vein of heteropteran fore- and hindwings is C+Sc; that Rs cannot be distinguished from R; that the hamus is part of M; that the glochis is a secondary structure. The difficulty of defining a vein is stressed. The functional significance of the hemielytron, cuneal fracture and longitudinal flexion lines is discussed. A preliminary ground-plan for Heteroptera wings is presented.