饥饿和交配对小地老虎飞行肌发育的影响

小地老虎Agrotis ypsilon(Rottemburg)成虫飞行肌的发育常受一些因素影响而发生变化,为探讨饥饿和交配行为对飞行肌发育的影响,通过电子显微镜对雌虫飞行肌(背纵肌)的肌原纤维、线粒体结构进行观察,结果显示:4日龄饥饿雌虫,肌原纤维直径、肌节长度、肌原纤维体积均显著(P<0.05)小于取食的。7日龄饥饿雌虫肌原纤维直径、肌节长度、肌原纤维体积分数较4日龄的差异均不显著(P≥0.05),而7日龄饥饿的肌原纤维直径显著(P<0.05)大于7日龄取食的;羽化10 d后,饥饿雌虫肌节长度显著(P<0.05)大于取食雌虫的,而肌纤维体积分数和线粒体体积分数均却小于后者。7、10、13日龄交配雌虫肌原纤维横切直径分别显著(P<0.05)小于同日龄非交配的;7、10、13日龄交配雌虫肌原纤维体积分数显著(P<0.05)小于非交配的,线粒体体积分数虽然无差异(P≥0.05),但是交配雌虫的早在4日龄便已明显(P<0.05)减小。上述结果表明:正常取食的小地老虎飞行肌4日龄后会发生降解现象;饥饿抑制飞行肌前期发育和中期的降解,而促进成虫末期肌原纤维的分解;交配能促进飞行肌的降解。     

Nutrition‐ and sex‐dependent utilization of body resources in relation to reproduction in a scorpionfly

Reproduction often comes at a cost of a reduction in body functions. In order to enhance their reproductive output, some insect species degenerate their thoracic muscles, typically resulting in reduced flight ability. From a life‐history trade‐off perspective, we expect the importance of body resource utilization to be amplified both with increased reproductive expenditure and with increased resource limitation. In this study, we measured age‐related changes in thorax weight, as a measure of flight muscle size, during a major part of the adult lifespan in males and females of the scorpionfly Panorpa vulgaris. The aim of the study was twofold: first to investigate whether scorpionflies have the potential to degenerate their flight muscles; second, and more importantly, to determine whether the magnitude of flight muscle degeneration is a plastic response in relation to resource availability, and if it differs between the sexes. The results clearly demonstrate that food availability does influence investment in flight muscle development. The build‐up of the thoracic muscles was strongly influenced by nutrient availability. Furthermore, the age‐related decrease in thorax weight was significantly different for males and females. Only females showed a strong age‐dependent decrease in thorax weight, indicative of muscle degeneration, yet no difference between food treatments was detected. For males, there was no significant directional change in thorax weight. Nevertheless, with increasing age, the difference in thorax weight between food treatments increased significantly. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 199–207.     

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.     

Neural- and endocrine control of flight muscle degeneration in the adult cricket,Gryllus bimaculatus

Neural- and endocrine mechanisms controlling degeneration of a dorsal longitudinal flight muscle, M112a, have been studied in adult Gryllus bimaculatus (Orthoptera: Gryllidae). Decapitation completely prevented muscle degeneration. Implantation of a pair of corpora allata or injection of juvenile hormone III into decapitated crickets caused muscle degeneration. Denervation of M112a resulted in reduction of muscle mass compared with that in sham-operated crickets. Denervation of M112a in decapitated crickets, however, did not affect muscle mass. Birefringence and ultrastructure of M112a showed an obvious regional difference in the onset of degeneration. Fibrillar structures of M112a always disappeared from the ventral to dorsal part. Distribution of axon terminals of motor neurons and mechanical responses to the motor nerve stimuli showed that M112a is composed of five motor units with similar twitch properties. When M112a was fully denervated, regional differences in degeneration disappeared. Partial denervation resulted in denervated muscle fibers losing birefringence earlier than innervated fibers. These results suggest that juvenile hormone causes breakdown of flight muscles, and neural factors control degeneration of flight muscles to some extent under the presence of the juvenile hormone.     

Oogenesis-flight syndrome in crickets: age-dependent egg production, flight performance, and biochemical composition of the flight muscles in adult female Gryllus bimaculatus

Age-dependent changes in flight performance, biochemical composition of flight muscles, and fresh mass of the flight muscles and ovaries were analysed in adult female two-spotted crickets, Gryllus bimaculatus. After the final moult the flight muscle mass increased significantly to a maximum at days 2 and 3. On day 2 the highest flight activity was also observed. Between days 2 and 3 the ovary weight started to rapidly increase due to vitellogenic egg growth, which continued at a high rate until day 10. With the onset of ovarial growth, flight performance decreased and the flight muscles started to histolyse. A high correlation between flight muscle mass and the content of protein, lipid, glycogen, and free carbohydrate in the flight muscle indicated that energy-rich substrates from the degrading flight muscles were used to fuel oogenesis, although flight muscle histolysis can provide only a small fraction of the substrates needed for egg production. In general, there was a clear trade-off between egg production and flight ability. Surprisingly, however, some females possessed well-developed ovaries but displayed no signs of flight muscle histolysis. This observation was corroborated by flight experiments which revealed that, although most flying females had small ovaries, some of them carried an appreciable amount of mature eggs, and thus, somehow managed to evade the oogenesis-flight syndrome.     

De-alation, flight muscle histolysis, and oocyte development in the striped ground cricket, Allonemobius fasciatus

ABSTRACT. Removal of hindwings from long-winged females of the striped ground cricket, Allonemobius fasciatus , DeGeer (Gryllidae), induces flight muscle histolysis and oocyte development. Such females develop oocytes as rapidly as do short-winged forms, while intact long-winged females retain their flight muscles and develop few oocytes.
Flight muscle histolysis occurs in starved long-winged females when they are de-alated. However, such females fail to mature oocytes. Implantation of corpora allata (CA) into long-winged females results in flight muscle histolysis as well as oocyte maturation even if their hindwings remain intact, indicating that flight muscle histolysis can take place without de-alation. It is likely that the CA are responsible for both flight muscle histolysis and oocyte development, and that CA activity is enhanced by de-alation.     

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.     

Development and Degeneration of Flight Muscles in Neochetina eichhorniae (Coleoptera; Curculionidae), Potential Biocontrol Agent of the Aquatic Weed, Eichorniae crassipes

The water hyacinth weevil, Neochetina eichhorniae, is an effective biological control agent of the aquatic weed Eichorniae crassipes. The adults under field conditions have degenerated indirect flight muscles that explains their inability to fly. A study on the factors initiating flight muscle development in adults was carried out. Among the various abiotic factors studied, density of weevils per plant and high temperature in presence of food initiated and accelerated flight muscle development. Absence of food did not influence muscle development. No inter-relationship between flight muscle development and degeneration could be observed.     

Muscle abnormalities in Drosophila melanogaster heldup mutants are caused by missing or aberrant troponin-I isoforms

We have investigated the molecular bases of muscle abnormalities in four Drosophila melanogaster heldup mutants. We find that the heldup gene encodes troponin-I, one of the principal regulatory proteins associated with skeletal muscle thin filaments. heldup3, heldup4, and heldup5 mutants, all of which have grossly abnormal flight muscle myofibrils, lack mRNAs encoding one or more troponin-I isoforms. In contrast, heldup2, an especially interesting mutant wherein flight muscles are atrophic, synthesizes the complete mRNA complement. By sequencing mutant troponin-I cDNAs we demonstrate that the molecular basis for muscle degeneration in heldup2 is conversion of an invariant alanine residue to valine. We finally show that degeneration of heldup2 thin filament/Z-disc networks can be prevented by eliminating thick filaments from flight muscles using a null allele of the sarcomeric myosin heavy chain gene. This latter observation suggests that actomyosin interactions exacerbate the structural or functional defect resulting from the troponin-I mutation.     

Physiological trade‐offs between flight muscle and reproductive development in the wing‐dimorphic cricket Velarifictorus ornatus

Morphology, flight muscles, and reproductive development were compared between long‐winged (LW) and short‐winged (SW) morphs of the cricket Velarifictorus ornatus (Shiraki) (Orthoptera: Gryllidae). There was no difference in body weight and pre‐oviposition between the two morphs, but LW individuals had better‐developed flight muscles than SW individuals during and after emergence of the adult. The flight muscles at adult emergence represented 11.9% of the total body weight in the LW female and 4.9% in the SW female. In addition, the weight of the flight muscle of LW females increased by 50% during the first 5 days, whereas the flight muscle of the SW variant increased only slightly after adult emergence. The process of oviposition in LW, SW, and de‐alated females varied: SW females produced more eggs at the early stage than LW females, but de‐alation could shorten the time until the peak of egg laying and caused histolysis of flight muscles of LW females. There was no significant difference in total egg production between the above three groups. In the male, unlike the female, the accessory glands of the two wing morphs enlarged continuously at the same rate. There was no difference between the two wing morphs in the mass of the testes during the first 7 days after adult emergence.     

Sexual dimorphism in the pyrgomorphid grasshopper Phymateus morbillosus: from wing morphometry and flight behaviour to flight physiology and endocrinology

Abstract In the field, adult males of the grasshopper Phymateus morbillosus are able to fly for up to 1 min and cover up to c. 100 m, whereas females, although fully winged, are apparently unable to get airborne. Morphometric data indicate that the males are lighter, have longer wings, a higher ratio of flight muscles to body mass, and a lower wing load value than females. It was investigated whether this inability of females to fly is related to fuel storage, flight muscle enzymatic design and/or the presence and quantitative capacity of the endocrine system to mobilize fuels. In both sexes, readily available potential energy substrates are present in the haemolymph in similar concentrations, and the amount of glycogen in flight muscles and fat bodies does not differ significantly between males and females. Mass-specific activities of the enzymes GAPDH (glycolysis), HOAD (fatty acid oxidation) and MDH (citric acid cycle) in flight muscles are significantly lower in females compared with males, and mitochondria are less abundant in the flight muscles of females. There is no significant difference between the ability of the two sexes to oxidize various important substrates. Both sexes contain three adipokinetic peptides in their corpora cardiaca; the amount of each peptide in female grasshoppers is higher than in males.
Thus, despite some differences listed above, both sexes appear to have sufficient substrates and the necessary endocrine complement to engage in flight. It seems more likely, from the morphometric data above, that the chief reason for flightlessness is that P. morbillosus females cannot produce sufficient lift for flight; alternatively, the neuronal functioning associated with the flight muscles may be impaired in females.     

HORMONAL CONTROL OF REVERSIBLE DEGENERATION OF FLIGHT MUSCLE IN THE COLORADO POTATO BEETLE, LEPTINOTARSA DECEMLINEATA SAY (COLEOPTERA)

In the hibernating (diapausing) Colorado potato beetle, Leptinotarsa decemlineata Say, the flight muscles show pronounced degeneration. The muscle fibrils are greatly reduced in diameter and the sarcosomes are virtually absent. Similar signs of degeneration could be produced by extirpation of the postcerebral complex of endocrine glands, the corpora cardiaca and corpora allata. Reimplantation of active postcerebral complexes resulted in a very rapid regeneration of the muscle fibrils and new formation of sarcosomes.     

Effect of juvenile hormone on acid phosphatases in the degenerating flight muscles of the Douglas-fir beetle, Dendroctonus pseudotsugae

Changes in acid phosphatase activity were used to estimate flight muscle degeneration in Dendroctonus pseudotsugae. Acid phosphatase positive sites increased numerically as well as in size in flight muscles of beetles attacking the host logs and those maintained on host bark chips. Topical treatment of beetles with a juvenile hormone analogue further increased the phosphatase activity. Juvenile hormone produced similar effects when applied to insects injected with eserine. An increase in the activity of acid phosphatases was also observed after incubation in culture medium with added juvenile hormone. The rôle of nerves and hormones in the degenerating muscles of D. pseudotsugae is compared with that in the permanently degenerating muscles during metamorphosis of some moths.     

长颚斗蟋长翅和短翅型雌成虫飞行肌发育、生殖力及寿命的比较

为探讨长颚斗蟋Velarifictorus asperses (Walker)翅型分化的生态学意义, 对室内饲养获得的长翅和短翅型雌成虫飞行肌和卵巢的发育, 以及长、 短翅型雌成虫的生殖力和寿命进行了比较研究。结果表明： 羽化当日, 长翅型雌成虫飞行肌重38.68±9.15 mg, 显著高于短翅型的17.53±4.44 mg （P<0.05）; 而二者卵巢重量无显著差异（P>0.05）, 分别为4.69±1.04 mg和4.88±0.97 mg。羽化后8 d内, 长翅型雌成虫飞行肌重量增加了48.9%, 短翅型雌成虫飞行肌重量无明显增加; 而短翅型雌成虫卵巢的重量增加至93.5±11.7 mg, 约为长翅型雌成虫的4.5倍。短翅型雌成虫的产卵前期显著短于长翅型, 其早期产卵量及总产卵量亦显著高于长翅型; 而两翅型雌成虫中后期产卵量及寿命无显著差异（P>0.05）。此外, 长翅型雌成虫在羽化后12 d开始发生飞行肌的降解, 飞行肌降解个体的卵巢重量显著高于未降解个体, 与短翅型相似。结果提示, 飞行肌与生殖系统的发育之间存在资源分配的权衡关系（trade-off), 且这种资源分配的差异可能会导致长翅型与短翅型个体在生活史策略上出现分化, 即长翅型个体具有飞行能力, 而短翅型个体则在生殖方面获得更高的收益, 且飞行肌的降解可能是长翅型个体由飞行转向生殖发育的生理信号。     

丽斗蟋翅二型雌虫飞行肌和卵巢发育间的资源分配差异

丽斗蟋Velarifictorus ornatus具有明显的翅二型现象, 长翅型与短翅型雌虫的卵巢和飞行肌存在着生理权衡。本研究分别应用蒽酮比色法、 硫代磷酸香草醛法、 考马斯亮蓝染液对羽化后10 d内两型雌虫飞行肌与卵巢内糖原、 总脂及蛋白质含量进行了定量分析。结果表明： 成虫羽化后10 d内, 两型雌虫体重无明显差异(P>0.05), 但短翅型雌虫怀卵量明显多于长翅型雌虫, 而人工脱翅能够促进长翅型雌虫怀卵量增加(P<0.05)。短翅型雌虫飞行肌内蛋白质、 糖原及总脂含量在成虫羽化后10 d内无明显变化, 但长翅型雌虫飞行肌内蛋白质在成虫羽化后3 d时达到最大值564.4±87.5 μg/♀, 糖原与总脂含量分别于羽化后第5天达到最大值85.2±21.7 μg/♀和5 284.7±1 267.4 μg/♀。然后开始下降, 各实验处理天数内, 长翅型雌虫飞行肌内蛋白质、 糖原及总脂含量都显著多于短翅型雌虫(P<0.05)。相反, 各处理天数内, 短翅型雌虫卵巢内蛋白质、 糖原及总脂含量则明显多于长翅型雌虫(P<0.05), 同时虫龄对蛋白质、 糖原及总脂在两型雌虫飞行肌与卵巢内分配也产生明显影响(P<0.05)。人工脱翅能够促进长翅型雌虫卵巢内蛋白质、 糖原及总脂含量增加, 同时诱导飞行肌内蛋白质、 糖原及总脂含量降低, 其中总脂含量在脱翅后10 d时降为2 394.9±1 461.8 μg/♀, 只有最大值的一半, 而与短翅型雌虫相似(P>0.05), 表明总脂为丽斗蟋飞行的主要能源物质。外用保幼激素Ⅲ能够促进长翅型雌虫卵巢内蛋白质、 糖原及总脂含量增加(P<0.05), 但对飞行肌内三者含量无明显影响(P>0.05), 外用早熟素Ⅰ对短翅型雌虫卵巢内蛋白质、 糖原及总脂含量亦无明显影响(P>0.05)。上述结果表明, 丽斗蟋长翅型雌虫首先将获得的资源用于发育飞行所需的飞行肌, 短翅型雌虫则首先将所获得的资源用于发育繁殖所需的卵巢, 但长翅型雌虫飞行肌与卵巢间的资源分配方式受保幼激素的影响。     

The ultrastructure of locust pleuroaxillary "steering" muscles in comparison to other skeletal muscles

The ultrastructure of locust muscles with different function is examined: the pleuroaxillary flight steering muscle is compared with a typical flight (power muscle) and a typical leg muscle, in particular with respect to sarcomere length, tracheation, mitochondria, and sarcoplasmatic reticulum. The pleuroaxillary muscle exhibits some features characteristic of flight muscles but most of the ultrastructure resembles that of leg muscles. This is in agreement with the innervation of this muscle by an octopaminergic neuron, which also innervates leg muscles but no other flight muscles. It also supports the hypothesis that octopaminergic neurons are important metabolic regulators and that the above muscle types exhibit important differences in energy metabolism.     

Flight muscle changes in male pine engraver beetles during reproduction: the effects of body size, mating status and breeding failure

Abstract. In a pattern that is typical for bark beetles, the lateralis medius flight muscle of male pine engravers, Ips pini Say (Coleoptera: Scolytidae), was found to decrease four-fold in volume (from mean ± SE = 1.36 ± 0.06 × 10^?2 mm³ to 0.34 ± 0.06 × 10^?2 mm³) within five days of the initiation of breeding galleries, and then to regenerate gradually to functional capacity during subsequent weeks. Although there was considerable variation in the timing and extent of flight muscle regeneration in males, this variation was not a consequence of differences between small (length < 4.0 mm) and large (length ≥ 4.0 mm) males. Two subsequent experiments revealed that male pine engravers can control the timing of flight muscle regeneration. In the first experiment, the flight muscles of males that were denied mates degenerated within 5 days of gallery initiation, but then showed complete regeneration 5 days later. In the second experiment, mated males that were removed from their breeding galleries (to simulate breeding failure) also showed extensive muscle degeneration 5 days after gallery initiation, but then regenerated their flight muscles to functional capacity by the tenth day. The ability of males to regenerate their flight muscles in response to conditions at the gallery is probably adaptive because it allows them to fly in search of new breeding opportunities when they are unable to attract mates or when breeding attempts fail.     

Superoxide formation preceding flight muscle histolysis in Solenopsis: fine structural cytochemistry and biochemistry

Summary In Solenopsis spp., muscle histolysis or breakdown is a normal process in females and is initiated in the flight muscles only immediately after a mating flight. Information regarding the presence of the oxyradical scavenging enzyme superoxide dismutase (SOD) and the formation of the radical oxygen intermediate superoxide (SO) during the early stages of flight muscle histolysis in this insect was investigated. In normal fibrillar flight muscles from control animals, SOD was immunolocalized to vesicular and tubular components of the sarcotubular system. Lanthanum tracer studies indicated that some of these SOD-positive structures might be tubulovesicles continuous with the extracellular space. Following the injection of virgin alates with experimental haemolymph obtained from artificially inseminated females, the membrane delimited elements of the sarcotubular system became increasingly swollen and dilated with time (from 60 to 120 minutes postinjection) with a concomitant decrease in SOD activity and an increase in oxyradical formation. Many similar vesicles were lanthanum-positive. SO was not seen in the sarcoplasmic vesicles and tubules of control insects. The biochemical quantification of SO release over a 2-hour period showed a marked increase in oxyradical formation following treatment with the experimental haemolymph in comparison to control insects. Also, the addition of superoxide dismutase depressed SO formation under these conditions. Despite the histochemical and biochemical changes seen in the muscles of experimental insects, by 2 hours post-treatment there was no evidence of muscle necrosis. From these studies on flight muscle histolysis/necrosis in Solenopsis it appears that the formation of oxyradicals might represent an early event in myopathogenesis and subsequent tissue involution. The generation of SO is more than likely to be associated with alterations in the normal structure, biochemistry and permeability of the biomembranes which delimit the sarcotubular system.     

Biochemical aspects of flight and flightlessness in Gryllus: flight fuels,enzyme activities and electrophoretic profiles of flight muscles from flight-capable and flightless morphs

Female Gryllus assimilis subjected to 4.5-7.7h continuous tethered flight had significantly lower amounts of total lipid, triglyceride and total soluble carbohydrate compared with unflown controls. A much greater amount of total lipid (6.3mg) was used during flight compared with carbohydrate (0.14mg). Flown individuals also had substantially reduced amounts of injected, radiolabeled [(14)C]-oleic acid. Activities of lipid, carbohydrate and amino acid catabolizing enzymes in flight muscles of G. assimilis and its wing-polymorphic congener, G. firmus, were very similar to activities in insects which primarily utilize lipid to power flight. By contrast, enzyme activities were very different from those in insects which primarily or exclusively use carbohydrate or proline as a flight fuel. These results strongly implicate lipid as the major flight fuel in Gryllus. Previous studies have shown that lipid levels are higher in flight-capable (long-winged) G. firmus that have small ovaries compared with flightless (short-winged) females that have large ovaries. Results of the present and previous studies collectively indicate that elevated lipid in long-winged G. firmus represents an energetic cost of flight capability which reduces (trade-offs with) reproduction in Gryllus. In G. firmus, mass-specific activities of nearly all enzymes were considerably reduced in underdeveloped, and to a lesser degree in histolyzed muscle, compared with fully-developed flight muscle. An important exception was alanine aminotransferase, whose activity was the highest in histolyzed muscle, and which may be involved in the catabolism of amino acids derived from muscle degradation. Despite the dramatic differences in enzyme activity, electrophoretic profiles of soluble flight-muscle proteins differed only subtly between fully-developed and underdeveloped or histolyzed flight muscles.