群居型和散居型东亚飞蝗雌成虫飞行肌的超微结构

应用电子显微镜对群居型和散居型东亚飞蝗Locusta migratoria manilensis（Meyen）雌成虫背纵肌进行了比较观察。结果表明：群居型和散居型成虫背纵肌具有类似的亚细胞结构,飞行肌的肌原纤维具有1∶3粗细丝比例,每根粗丝由6根细丝环绕排列成六角形结构。飞行肌的发育和线粒体的形成均是渐进的过程,在不同日龄成虫间存在差异。肌节长度为2.1～3.4 μm;7和10日龄时群居型成虫肌节长度小于散居型;7日龄群居型肌原纤维直径显著大于散居型。背纵肌内线粒体含量约占肌纤维的20%～43%,两型飞蝗之间存在着显著的差异,7日龄时群居型线粒体占肌原纤维的比例高达42.96%,而散居型的只有22.45%;10日龄群居型线粒体含量为41.32%,散居型线粒体29.98%。上述差异可能是东亚飞蝗群居型成虫飞行能力显著强于散居型成虫的重要原因之一。     

食物胁迫对翅二型丽斗蟋飞行肌和繁殖发育的影响

前期研究表明,在食物充足的条件下,翅二型丽斗蟋雌成虫长、短翅型间存在着资源投入和收益的权衡关系(trade-off);而雄成虫长短翅型间不存在此类权衡关系。在自然条件下,昆虫可能遭受食物缺乏的胁迫,因而进一步就食物胁迫对丽斗蟋飞行肌和繁殖发育的影响进行了研究。结果表明,在食物胁迫的条件下,长翅雌虫仍维持飞行肌的发育,但繁殖发育受到显著的抑制;而短翅雌虫飞行肌显著降解,繁殖发育亦维持在较高水平。说明即使是营养缺乏时,其雌成虫长、短翅型也依然存在资源配置的差异,具飞行肌和繁殖发育的权衡关系。长翅雄虫飞行肌的重量与食物充足组并无显著差异,但精巢的干重显著降低;而短翅雄虫在食物胁迫条件下飞行肌显著降解,但其精巢重量与食物充足组并无显著差异。可以认为,丽斗蟋雄虫的长、短翅型间也存在飞行肌和繁殖发育的权衡关系。     

The physiological costs of flight capability in wing-dimorphic crickets

Nutritional indices, triglyceride levels and flight muscle developmental profiles were compared between long-winged (LW) and short-winged (SW; flightless) morphs of the cricketsGryllus rubens Scudder andG. firmus Scudder. This was done to identify potential physiological costs of flight capability in adults. The LW morph of each species converted a lower proportion of assimilated nutrients into biomass (reduced ECD) than did the SW morph. This documents increased respiratory metabolism in the LW morph. Triglyceride concentration was higher in LW vs. SW adults. This suggests that the elevated respiration in the LW morph may be at least partially due to the increased biosynthesis of this high energy substance. Preliminary data indicate higher respiration rates of LW functional vs. SW vestigial flight muscles. Collectively, these data suggest that the energetic cost of flight capability in adults results from biosynthesis of triglyceride flight fuel and flight muscle maintenance but not flight muscle growth. No flight muscle growth was observed in adults.     

Flight muscles polymorphism in a flightless bug, Pyrrhocoris apterus (L.): developmental pattern, biochemical profile and endocrine control

The flightless bug Pyrrhocoris apterus (L.) is polymorphic for both wing length and flight muscle development. The developed flight muscles of macropterous adults of both sexes first enlarge their volume during the first 5 days after adult emergence, but are then histolyzed in all males and females older than 10 and 14 days, respectively. The flight muscles of brachypterous adult males and females are underdeveloped due to their arrested growth. The total protein content of histolyzed dorsolongitudinal flight muscles from 21-day-old macropterous adults of both sexes is lower than that of developed dorsolongitudinal flight muscles in 5-10-days-old macropterous bugs, but substantially higher than the protein content of underdeveloped dorsolongitudinal flight muscles from adult brachypters. Histolyzed dorsolongitudinal flight muscles differ from the developed ones by decreased quantities of 18 electrophoretically separated proteins. Histolysis of developed dorsolongitudinal flight muscles is accompanied by significant decreases in citrate synthase, glyceraldehyde-3-phosphate dehydrogenase and β-hydroxyacyl-CoA dehydrogenase enzyme activities and an increase in alanine aminotransferase activity, and can be precociously induced by application of a juvenile hormone analogue. This is the first report of flight muscle polymorphism, histolysis of developed flight muscles and its endocrine control in insects displaying non-functional wing polymorphism.     

Effect of ecdysterone and juvenoid on the developmental involution of flight muscles in Acheta domestica

Morphogenesis and degeneration of the flight muscles in Acheta domestica was studied. The dorso-longitudinal flight muscles (DLMs) degenerate during the fourth day after adult ecdysis and the dorso-ventral flight muscles (DVMs) on the fifteenth day. In the presence of an intact innervation the degeneration of the DLMs can be retarded for 2 days by the injection of ecdysterone into very young adults. This retardation may also result in hypertrophy of the muscle fibres. The injection of ecdysterone, even in high doses, did not affect the flight muscle remnants. No notable changes have been found in the degeneration of DLMs by ovarectomy. Thus, the degeneration of flight muscles and the development of ovaries appear to be independent processes.The DLMs are homogeneous in fibre pattern in respect to succinic dehydrogenase, an important oxidative enzyme, and to ATPase activity, but the muscle fibres do not show any phosphorylase activity.     

一日龄饥饿对粘虫成虫卵巢发育和飞行能力的影响

为了明确羽化后0～24 h (1日龄)饥饿处理对迁飞型粘虫Mythimna separata (Walker)生殖系统和飞行系统发育的影响,对1日龄饥饿处理后粘虫的卵巢发育级别、产卵前期、飞行肌和飞行能力进行了系统研究。结果表明, 1日龄饥饿对粘虫成虫卵巢发育级别、产卵前期、中胸背纵肌干重、飞行能力等均有显著的影响。饥饿后成虫卵巢发育级别显著高于对照,产卵前期显著短于对照。成虫中胸背纵肌干重从饥饿后96 h开始下降,至120 h时饥饿粘虫(5.1 mg)显著低于对照(5.86 mg)。成虫飞行能力从饥饿后96 h开始显著低于对照,此时饥饿处理粘虫蛾的飞行距离平均为22.03 km,飞行时间平均为4.07 h,显著低于同时期的对照粘虫的飞行距离(42.3 km)和飞行时间(7.99 h),尽管在饥饿后72 h内差异不显著。实验结果显示,1日龄饥饿可以显著抑制粘虫飞行系统的发育,加速飞行向生殖的转变。     

Juvenile Hormone and host-plant colonization by the black bean aphid, Aphis fabae

Abstract Host-plant colonization by winged, summer forms of Aphis fabae Scop, involves the resumption of embryogenesis and larviposition, leading eventually to flight muscle degeneration. Topical application of Juvenile Hormone I to young adults which (a) had access to the host plant, (b) were starved, (c) were starved and treated with precocene III, or (d) were decapitated shortly after the final ecdysis suggests that embryogenesis and flight muscle histolysis may be stimulated by an increase in Juvenile Hormone titres after settling. The duration of the pre-reproductive period and the initial reproductive rate were not significantly affected, possibly because other neuroendocrine factors are involved in parturition.     

Flight duration and flight muscle ultrastructure of unfed hawk moths

Flight muscle breakdown has been reported for many orders of insects, but the basis of this breakdown in insects with lifelong dependence on flight is less clear. Lepidopterans show such muscle changes across their lifespans, yet how this change affects the ability of these insects to complete their life cycles is not well documented. We investigated the changes in muscle function and ultrastructure of unfed aging adult hawk moths (Manduca sexta). Flight duration was examined in young, middle-aged, and advanced-aged unfed moths. After measurement of flight duration, the main flight muscle (dorsolongitudinal muscle) was collected and histologically prepared for transmission electron microscopy to compare several measurements of muscle ultrastructure among moths of different ages. Muscle function assays revealed significant positive correlations between muscle ultrastructure and flight distance that were greatest in middle-aged moths and least in young moths. In addition, changes in flight muscle ultrastructure were detected across treatment groups. The number of mitochondria in muscle cells peaked in middle-aged moths. Many wild M. sexta do not feed as adults; thus, understanding the changes in flight capacity and muscle ultrastructure in unfed moths provides a more complete understanding of the ecophysiology and resource allocation strategies of this species.     

枣实蝇成虫飞行能力的测定

【目的】为了明确枣实蝇Carpomya vesuviana Costa成虫飞行扩散能力及相关因子对其飞行能力的影响。【方法】本研究以SUN-FL型智能昆虫飞行信息系统（飞行磨）吊飞方法, 测定了不同日龄、性别的枣实蝇成虫的飞行能力, 并探究了温度对枣实蝇飞行能力的影响。【结果】羽化后12 d左右的枣实蝇飞行能力最强, 雌虫平均飞行距离和最远飞行距离分别为1.037和3.192 km, 雄虫分别为0.943和3.085 km; 枣实蝇飞行能力随着日龄的增加呈现先增强后减弱的趋势; 相同日龄的雌成虫平均飞行距离、平均飞行时间略高于雄虫, 雌、雄虫的平均飞行距离、平均最快飞行速度、平均飞行时间之间没有显著性差异; 环境温度28～34℃为枣实蝇最佳飞行温度区间, 且31℃条件下飞行能力最强。【结论】由此可见, 枣实蝇成虫具有较强的迁飞扩散能力。     

Presynaptic terminals persist following degeneration of "flight" muscle during development of a flightless grasshopper

We have studied the development of a neuromuscular system for which mature function has been lost through evolution in the grasshopper, Barytettix psolus (Cohn and Cantrall, 1974). Barytettix is flightless throughout life and has only vestigial wings that are incapable of active movement. Adult Barytettix lack muscles homologous to the indirect flight muscles of locusts and grasshoppers that fly, while other thoracic muscles are similar. We have found, using light and electron microscopic examination of tissues from various developmental stages, that the metathoracic dorsal longitudinal muscle is present and is innervated during nymphal life but is absent in adults. Yet its nerve persists and, in the adult, contains axonal presynaptic specializations opposite inappropriate targets such as glial processes and basal lamina. Our findings indicate that selective muscle death during development is one mechanism underlying the reduction of the flight system of Barytettix through evolution. The finding that presynaptic terminals persist in the absence of the muscle indicates that the muscle and its innervation follow programs of development that are at least partially independent and reinforces the concept that in insects motorneurons, and perhaps neurons in general, are not dependent upon trophic influences from their targets for survival and maintenance of their differentiated phenotype.     

Critical Flight Time for Switch from Flight to Reproduction in the Wing Dimorphic Cricket Velarifictorus aspersus

Flight dimorphism has been considered to result from a balance of costs and benefits between flight capability and reproduction. The validity of the hypothesis, however, has been challenged recently. In this study, we examined the effect of flight time on trade-off between flight capability and reproductive development in Velarifictorus aspersus and we found that flight of 5 min did not promote reproductive development of long-winged (LW) adults, but flight of 30, 60, or 120 min could promote reproductive development both in female and male crickets. The results indicate that flight time may serve as a signal for LW V. aspersus to switch from migration to reproduction, and trade-off between flight ability and reproduction may be attenuated when flight time reaches a critical threshold. In addition, rapid reproductive development occurred before dealation when LW insects were allowed to fly for 30 min, which indicates that flight may influence reproductive development directly. Food consumption of short-winged adults was significantly higher than that of unflown LW adults or LW adults with 5 min flight, but similar to that of LW adults with 30, 60, or 120 min flight, suggesting that difference of reproductive development may be positively correlated with their food consumption.     

取食和交配对苹小吉丁飞行能力的影响

【目的】苹小吉丁Agrilus mali是一种严重危害苹果树的钻蛀性害虫。本研究旨在明确苹小吉丁的飞行扩散能力及对其飞行能力产生影响的关键因子。【方法】以SUN-FL型智能飞行磨系统对苹小吉丁不同日龄雌雄成虫的飞行能力进行了测定,同时评价了取食和交配情况对其飞行能力的影响。【结果】苹小吉丁飞行能力均随日龄的增加先增强后逐渐降低,初羽化的成虫飞行能力最低,11日龄成虫的飞行能力最强。雌成虫飞行能力强于雄成虫。在24 h内雌雄成虫的最长飞行距离分别为0.4165和0.3559 km;最长飞行时间分别为0.4582和0.4873 h;最大飞行速度分别为2.4639和1.8561 km/h。取食的3日龄雌成虫的平均飞行距离和平均飞行时间分别为0.047 km和0.048 h,雄成虫的分别为0.044 km和0.042 h;而未取食的雌成虫平均飞行距离和平均飞行时间仅分别为0.016 km和0.013 h,雄成虫的仅分别为0.013 km和0.012 h。交配对飞行能力的影响存在性别差异,已交配雌成虫的飞行能力要强于未交配雌成虫的,而已交配雄成虫的飞行能力却低于未交配雄成虫的。【结论】日龄对苹小吉丁成虫的飞行能力影响作用显著。取食显著提高苹小吉丁雌雄成虫的飞行能力,交配显著提高雌成虫飞行能力。     

Variations in fuel use in the flight muscles of wing-dimorphic Gryllus firmus and implications for morph-specific dispersal

Although a considerable amount of information is available on tradeoffs in wing-polymorphic insects, only limited data are available on the relationship between flight and biochemical variation within species. In the current study, we compared the biochemical basis in the dorsolongitudinal flight muscle of the wing-dimorphic sand cricket, Gryllus firmus Scudder, with respect to tradeoffs in energy resources related to morph-specific flight, including glycogen, trehalose, and triglycerides. Our results show that levels of glycogen and trehalose in long-winged adults (LW[f]) were significantly higher before dispersal, on days 5 and 7. Considering that this is the period during which long-winged adults are flight-capable, these results suggest that both glycogen and trehalose are important to flight. However, levels of triglycerides in short-winged crickets (SW) were higher than in long-winged crickets, suggesting that triglycerides are not directly related to initial flight. In SW adults, triglyceride content on days 5 and 7 was significantly higher just before lights off than at the same time on day 1 or at any other time after lights on all other days. This suggests that triglycerides are probably related to reproductive behaviors, such as mating and oviposition, in the SW morph. In addition, flight muscle water content was significantly lower in the LW(f) morph than in the SW morph.     

Juvenile hormone regulation on the flight capability of Bactrocera dorsalis (Diptera: Tephritidae)

The oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), is considered a major economic threat in many regions worldwide. In order to better understand the flight capacity of B. dorsalis and its physiological basis, the functions and regulatory roles of juvenile hormone (JH) in the flight muscle of B. dorsalis were studied under a controlled environment. JH titer of B. dorsalis varied with age and sex. Females have higher JH titers and better flight capabilities than males, given that the increase in JH also corresponded to the ovarian development and maturation in females. The flight duration and distance of both males and females increased with the gradual increase of JH titer after adult emergences. Both JH titer and flight capability peaked in 15-d-old adult and declined subsequently with age. Flight activity stimulated the production of JH as adults flown for 24 h on the flight mills have the highest JH titers compare to adults flown on shorter flight durations. Adults treated with 0.5 µg and 5 µg of JH III were able to fly long durations and long distances, nevertheless when JH titer was too low or too high, it would restrict the flight ability of the fly. The mutual reinforcement of JH and flight activity provides fundamental understanding on the physiological aspects of the flight capability and dispersal, which facilitates strategies for the long-term control of this destructive pest.     

Induced neuroma formation and target muscle perturbation in the giant fiber pathway of the Drosophila temperature-sensitive mutant shibire

Summary The temperature-sensitive mutation shibire (shi) in Drosophila melanogaster is thought to disrupt membrane recycling processes, including endocytotic vesicle pinch-off. This mutation can perturb the development of nerves and muscles of the adult escape response. After exposure to a heat pulse (6 h at 30° C) at 20 h of pupal development, adults have abnormal flight muscles. Wing depressor muscles (DLM) are reduced in number from the normal six to one or two fibers, and are composed of enlarged fibers that appear to represent fiber fusion; large spaces devoid of muscle fibers suggested fiber deletion. The normal five motor axons are present in the peripheral nerve PDMN near the ganglion. However, while some motor axons pass dorsally to the extant fibers, other motor axons lacking end targets pass into an abnormal posterior branch and terminate in a neuroma, i.e., a tangle of axons and glia without muscle target tissue. Hemisynapses are common in axons of the proximal PDMN and within the neuroma, but they are rarely seen in control (no heat pulse) shi or wild-type flies. All surviving muscle fibers are innervated; no muscle tissue exists without innervation. Fibrillar fine structure and neuromuscular synapses appear normal. Fused fibers have dual innervation, suggesting correct and specific matching of target tissue and motor axons. Motor axons lacking target fibers do not innervate erroneous targets but instead terminate in the neuroma. These results suggest developmental constraints and rules, which may contribute to the orderly, stereotyped development in the normal flight system. The nature of the anomalies inducible in the flight motor system in shi flies implies that membrane recycling events at about 20 h of pupal development are critical to the formation of the normal adult nerve-muscle pattern for DLM flight muscles.     

Presynaptic terminals persist following degeneration of “flight” muscle during development of a flightless grasshopper

We have studied the development of a neuromuscular system for which mature function has been lost through evolution in the grasshopper, Barytettix psolus (Cohn and Cantrall, 1974). Barytettix is flightless throughout life and has only vestigial wings that are incapable of active movement. Adult Barytettix lack muscles homologous to the indirect flight muscles of locusts and grasshoppers that fly, while other thoracic muscles are similar. We have found, using light and electron microscopic examination of tissues from various developmental stages, that the metathoracic dorsal longitudinal muscle is present and is innervated during nymphal life but is absent in adults. Yet its nerve persists and, in the adult, contains axonal presynaptic specializations opposite inappropriate targets such as glial processes and basal lamina. Our findings indicate that selective muscle death during development is one mechanism underlying the reduction of the flight system of Barytettix through evolution. The finding that presynaptic terminals persist in the absence of the muscle indicates that the muscle and its innervation follow programs of development that are at least partially independent and reinforces the concept that in insects motorneurons, and perhaps neurons in general, are not dependent upon trophic influences from their targets for survival and maintenance of their differentiated phenotype.     

Mechanical analysis of Drosophila indirect flight and jump muscles

The genetic advantages of Drosophila make it a very appealing choice for investigating muscle development, muscle physiology and muscle protein structure and function. To take full advantage of this model organism, it has been vital to develop isolated Drosophila muscle preparations that can be mechanically evaluated. We describe techniques to isolate, prepare and mechanically analyze skinned muscle fibers from two Drosophila muscle types, the indirect flight muscle and the jump muscle. The function of the indirect flight muscle is similar to vertebrate cardiac muscle, to generate power in an oscillatory manner. The indirect flight muscle is ideal for evaluating the influence of protein mutations on muscle and cross-bridge stiffness, oscillatory power, and deriving cross-bridge rate constants. Jump muscle physiology and structure are more similar to skeletal vertebrate muscle than indirect flight muscle, and it is ideal for measuring maximum shortening velocity, force-velocity characteristics and steady-state power generation.