Effects of wing-pad removal and corpus allatum implantation on development of wings, flight muscles, and related structures in the striped ground cricket, Allonemobius fasciatus

ABSTRACT. Removal of a hindwing pad from late instar nymphs of the striped ground cricket, Allonemobius fasciatus DeGeer (Gryllidae) inhibits the formation of long-winged adults. All nymphs become short-winged when their hindwing pad is removed during the sixth (penultimate) instar or during the first 2 days of the seventh instar. When a hindwing pad is removed on day 4 of the seventh instar or later, there is no effect on wing development and at least 50% of the crickets emerge as long-winged adults as in controls.
The period sensitive for removal of a hindwing pad varies among different structures, e.g. elytra, hindwings, flight muscles, and the acrotergite of the first abdominal segment. As a result, some intermediate forms are produced when a hindwing pad is removed in the middle of the seventh instar.
Implantation of corpora allata (CA) into late instar nymphs also inhibits formation of long-winged adults. When CA are implanted on day 2 or 3 of the seventh instar, some of the resulting adults have abnormally short elytra. Implantation of CA at an earlier stage produces supernumerary (eighth instar) nymphs.     

Seasonal variation in embryonic diapause of the striped ground cricket, Allonemobius fasciatus

ABSTRACT. The incidence and intensity of embryonic diapause in the striped ground cricket, Allonemobius fasciatus DeGeer (Gryllidae), is influenced by the date of oviposition and the incubation temperature. At 20C, embryos develop normally until the end of the appendage-formation stage when diapause occurs. The intensity of 'winter' diapause at this stage is greatest in eggs laid early in the season. Incubation at higher temperature induces a different and earlier 'summer' diapause. The higher the temperature the earlier the stage at which this developmental suppression is imposed. At 27 and 30C, some individuals develop without any interruption and hatch within 20 days. The proportion of these fast-developing eggs is low in summer but increases towards the end of the laying season. In nature, this species is univoltine and precocious hatching before winter is unlikely.
When embryos diapausing at an early stage at 27C are transferred to low temperatures, they resume development and enter winter diapause. The time required to reach the winter-diapause stage after transfer is inversely related to the temperature (30-30C). At 30C, sunmer diapause is neither induced nor maintained.     

Programmed cell death in flight muscle histolysis of the house cricket

We have characterized the process of flight muscle histolysis in the female house cricket, Acheta domesticus, through analysis of alterations of tissue wet weight, total protein content, and percent shortening of the dorsal longitudinal flight muscles (DLMs). Our objectives were to (1) define the normal course of histolysis in the cricket, (2) analyze the effects of juvenile hormone (JH) removal and replacement, (3) determine the effects of cycloheximide treatment, and (4) examine patterns of protein expression during histolysis. Our results suggest that flight muscle histolysis in the house cricket is an example of an active, developmentally regulated cell death program induced by an endocrine signal. Initial declines of total protein in DLMs indicated the JH signal that induced histolysis occurred by Day 2 and that histolysis was essentially complete by Day 3. Significant reductions in tissue weight and percent muscle shortening were observed in DLMs from Day 3 crickets. Cervical ligation of Day 1 crickets prevented histolysis but this inhibition could be reversed by continual topical treatments with methoprene (an active JH analog) although ligation of Day 2 crickets did not prevent histolysis. A requirement for active protein expression was demonstrated by analysis of synthesis block by cycloheximide and short-term incorporation of (35)S-methionine. Treatment with cycloheximide prevented histolysis. Autofluorographic imaging of DLM proteins separated by electrophoresis revealed apparent coordinated regulation of protein expression.     

Flight threshold, wing muscle histolysis, and alary polymorphism: correlated traits for dispersal tendency in the Gerridae

ABSTRACT. 1. This paper tests the hypothesis that selection for dispersal ability within a species influences not only the occurrence and extent of wing reduction but also the tendency or ability of the macropterous individuals to fly.
2. Flight thresholds of four species of waterstriders (Hemiptera; Gerridae) were assessed using a tethered flight technique. The species tested varied from monomorphic macropterous ( Limnoporus dissortis Drake and Harris), through seasonally polymorphic ( Gerris comatus Drake and Hottes and G. buenoi Kirkaldy), to primarily apterous ( G.remigis Say).
3. Condition of the indirect, mesothoracic flight muscles, and presence or absence of mature or developing eggs (for females) were determined by dissection of all individuals immediately following flight testing. Only individuals with normal muscles were included in the analysis of flight thresholds.
4. Comparisons among species revealed that average flight threshold and extent of flight muscle histolysis were negatively associated with the proportion of macropterous individuals. Wing reduction was also associated with significant seasonal variation in flight threshold, particularly among females.
5. These results support our initial hypothesis, and further indicate that, within the Gerridae, dispersal tendency depends not only on the proportion of macropters but also on the dispersal capability of the macropterous individuals.     

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。     

Microsatellites in the striped ground crickets,Allonemobius (Orthoptera: Gryllidae)

Polymorphic di‐, tri‐ and tetranucleotide repeats were examined in Allonemobius to determine whether they could serve as useful markers in studies of sperm precedence, population genetics and hybrid zone structure. Ten microsatellite DNA loci were sufficiently polymorphic to be used for paternity tests and showed no evidence of linkage disequilibrium or deviations from Hardy–Weinberg equilibrium in Allonemobius socius. Nine of 10 of these microsatellites can be amplified from three other Allonemobius species, suggesting that these markers will have widespread utility in this ground cricket genus.     

外用保幼激素与早熟素对丽斗蟋翅二型个体飞行与生殖发育间生理权衡的影响（英文）

为探讨丽斗蟋Velarifictorus ornatus翅二型个体飞行与生殖发育间生理权衡的内分泌控制机理, 本研究调查了外用保幼激素Ⅲ(JH-III)与早熟素Ⅰ(P-I)对丽斗蟋翅二型个体飞行肌与生殖发育的影响。结果表明： 成虫羽化后当日分别注射1, 5, 10和25 μg保幼激素7 d后, 显著促进了丽斗蟋长翅雌虫卵巢发育, 卵巢重量分别从对照组的16.8±11.4 mg/♀增加到43.9±10.7, 33.6±14.0, 56.8±7.6和 39.3±30.7 mg/♀; 但对卵巢内怀卵量无显著影响。相反, 外用保幼激素则诱发飞行肌降解, 1, 5和10 μg JH-III处理组飞行肌重量分别下降为12.9±4.7, 11.7±4.8和8.8±0.8 mg/♀, 显著低于对照组飞行肌重量(17.7±1.6 mg)。对短翅雌虫注射P-I时, 当注射的剂量超过50 μg/♀时, 能够显著抑制卵巢发育, 而低于50 μg/♀时则对卵巢发育无明显影响。外用JH-III对丽斗蟋长翅雄虫飞行肌、 精巢、 附腺的发育无明显影响; 外用P-I对短翅型雄虫精巢与附腺的发育也无明显影响。因此, 丽斗蟋翅二型雌虫与雄虫的飞行肌与生殖器官的内分泌控制机理可能存在差异。     

Immune suppression and the cost of reproduction in the ground cricket, Allonemobius socius

One of the most common life history trade-offs in animals is the reduction in survivorship with increasing reproductive effort. Despite the prevalence of this pattern, its underlying physiological mechanisms are not well understood. Here we test the hypothesis that immune suppression mediates this phenotypic trade-off by manipulating reproductive effort and measuring immune function and mortality rates in the striped ground cricket, Allonemobius socius. Because A. socius males provide females with a hemolymph-based nuptial gift during copulation, and many structural components of immunity reside in the hemolymph, we also predicted that sexual selection may differentially affect how disease resistance evolves in males and females. We found that an increased mating effort resulted in a reduced immune ability, coupled with an increased rate in age-specific mortality for both sexes. Thus, immune suppression appears to be a link between reproductive effort and cost in this system. In addition, males and females appeared to differentially invest in several aspects of immunity prior to mating, with males exhibiting a higher concentration of circulating hemocytes and a superior bacterial defense capability. This pattern may be the result of previously established positive selection on gift size due to its affect on female fecundity. In short, female choice for larger gifts may lead to a sexually dimorphic immune ability.     

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.     

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.     

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。     

Scale-independent criteria and scale-dependent agents determining the structure of a ground cricket mosaic hybrid zone (Allonemobius socius – Allonemobius fasciatus)

The structure of the hybrid zone between the ground crickets, Allonemobius socius and Allonemobius fasciatus , approximates an environmental mosaic based on temperature/moisture at regional spatial scales. In the present study, we show that the micro-geographic spatial structure (i.e. single fields) of this hybrid zone is governed by the same criteria. Thus, the criteria that structure this hybrid zone are scale independent, even though the agents that implement these criteria may differ at various scales (climate, latitude, and elevation at regional scales; grass height, slope aspect, and field use at micro-geographic scales). Additionally, the study demonstrates a previously unknown barrier to genetic exchange in this system that acts before conspecific sperm precedence.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 94 , 777–796.     

Variation in singing behaviour among morphs of the sand field cricket,Gryllus firmus

1. Trade‐offs play a fundamental role in the evolution of many traits. 2. In wing‐polymorphic field crickets, the long‐winged morph can disperse from unfavourable environments, but has lower reproductive success than the short‐winged morph, because of costs associated with flight capability. 3. However, long‐winged individuals may minimise costs in favourable environments by histolysing their flight muscles and becoming flightless. 4. Few studies have examined how flight‐muscle histolysis affects male signalling and mate attraction. 5. We examined differences in singing activity and song characteristics among the flightless (short‐winged and histolysed long‐winged) and the flight‐capable male morphs, and female preferences for male song, in the sand field cricket. 6. We found: (i) both flightless morphs sang more than the flight‐capable morph, (ii) song characteristics varied among the three morphs, and (iii) females preferred songs characteristic of the long‐winged morphs. 7. Histolysis should increase mating success of long‐winged males because it increases singing activity. 8. Histolysed long‐winged males may have higher mating success than short‐winged males as they sing as frequently but produce more attractive songs. 9. Therefore, plasticity within the long‐winged morph may reduce costs of maturing in environments from which dispersal is not advantageous; non‐flying morphs may be pursuing different reproductive tactics.     

Interaction between flight,reproductive development and oviposition in the pine weevil Hylobius abietis

• 1 The development of reproductive and flight capacity of pine weevils Hylobius abietis during the spring and their dispersal to, and subsequent development at, new clearfell oviposition sites comprise key phases in their life cycle in managed forests. At an old clearfell site where autumn‐emerging weevils had overwintered, weevils were trapped as they re‐emerged in the spring and tested for their ability to fly and then dissected to determine the degree of wing muscle and egg development.
• 2 Re‐emerging weevils were most abundant in pine growing at the edge of the clearfell and, over most of the trapping period (April to June), their capacity for flight (proportion flying and wing muscle width) was more advanced than in weevils from the clearfell itself, with a similar trend in the degree of reproductive development (proportion with mature eggs and egg volume).
• 3 In weevils from the clearfell, flight capacity and reproductive development increased concurrently to a peak around mid‐May. In weevils from pine, wing muscles were already well developed at the start of trapping, although few of them flew. Their more advanced development was attributed to the increased opportunities for maturation feeding after emergence in the previous autumn.
• 4 In the spring, weevils reached the canopy of trees for maturation feeding by walking and, to a lesser extent, by flight. Weevils dispersed by flight to oviposition sites in mid‐May when most of them were reproductively mature. After arrival, flight ability and wing muscle size declined rapidly but egg production was maintained until most weevils had stopped flying. When wing muscles reached their minimum size, there was a marked decline in egg size, suggesting that wing muscle breakdown is important in maintaining egg production at oviposition sites. Prospects for further wing muscle and reproductive development are discussed.

     

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。     

沙蟋飞行肌中保幼激素滴度的昼夜节律

沙蟋Gryllus firmus是一种翅多型性的昆虫, 是研究种内迁飞和生殖调控的模式生物。本研究应用高效液相色谱仪（HPLC）、 气相色谱-质谱联用仪(GC-MS)对沙蟋长翅（有飞行能力）和短翅（无飞行能力）雌虫飞行肌内保幼激素（juvenile hormone, JH）和脂肪酸进行了定性定量分析。结果表明： 在温度28℃, 光周期16L∶8D条件下, 第5和第7日龄的沙蟋长翅雌虫飞行肌中JH的滴度具有明显的昼夜节律, 在飞行前（即关灯前）4 h, JH的滴度分别由386.52±68.40 ng/g和630.36±37.26 ng/g增加至1 327.53±277.98 ng/g和1 685.77±143.95 ng/g, 与短翅型SW相比分别增加了约3.4倍与2.7倍 (P＜0.05)。而相同日龄的短翅雌虫及第1日龄的两型雌虫均无明显的节律变化。进一步在第5和7日龄的长翅雌虫中发现了一个16C的脂肪酸--14-甲基十五烷酸, 也具有节律变化且与JH节律出现的时间相吻合, 而在无飞行能力的沙蟋中没有发现这种现象。实验还证明JH滴度的增加和节律不是由飞行肌的重量或者飞行肌重量比的变化所致。这些发现有助于探讨和了解保幼激素对飞行调控的内在机理。     

Mammalian oocyte growth and development in vitro

This paper is a review of the current status of technology for mammalian oocyte growth and development in vitro. It compares and contrasts the characteristics of the various culture systems that have been devised for the culture of either isolated preantral follicles or the oocyte-granulosa cell complexes from preantral follicles. The advantages and disadvantages of these various systems are discussed. Endpoints for the evaluation of oocyte development in vitro, including oocyte maturation and embryogenesis, are described. Considerations for the improvement of the culture systems are also presented. These include discussions of the possible effects of apoptosis and inappropriate differentiation of oocyte-associated granulosa cells on oocyte development. Finally, the potential applications of the technology for oocyte growth and development in vitro are discussed. For example, studies of oocyte development in vitro could help to identify specific molecules produced during oocyte development that are essential for normal early embryogenesis and perhaps recognize defects leading to infertility or abnormalities in embryonic development. Moreover, the culture systems may provide the methods necessary to enlarge the populations of valuable agricultural, pharmaceutical product-producing, and endangered animals, and to rescue the oocytes of women about to undergo clinical procedures that place oocytes at risk. © 1996 Wiley-Liss, Inc.     

Leupeptin, a protease inhibitor, blocks insemination-induced flight muscle histolysis in the fire ant Solenopsis

The effect of the protease inhibitor leupeptin on flight muscle histolysis in queen fire ants was studied by electron microscopy. In untreated animals artificially inseminated, muscle involution was apparent at 6 hr post-insemination and complete by 24 hr post-insemination. However, in animals pre-treated with leupeptin and subsequently artificially inseminated, no morphologic evidence of flight muscle breakdown was seen at any interval between 6 and 24 hr post-insemination. Such information appears to indicate that one or more proteases are involved in the process of insemination-induced muscle atrophy in fire ants. The most likely candidate is a soluble, calcium-activated myofilament-associated protease.     

基于转录组测序的楚雄腮扁叶蜂飞行肌蛋白及飞行能量代谢相关酶挖掘

本研究旨在阐明楚雄腮扁叶蜂Cephalcia chuxiongica Xiao飞行肌结构蛋白及飞行能量代谢相关酶基因信息。首先采用电镜技术对楚雄腮扁叶蜂飞行肌进行了观察,结果表明,肌原纤维(由粗丝和细丝组成,其数量比例为1∶3)是飞行肌的基本成分,肌原纤维横切面平均面积为0.771±0.042μm²,肌节平均长度为2.698±0.116μm。进一步通过飞行肌转录组分析,共筛选到11大类飞行肌结构蛋白,其中肌球蛋白(Myosin)和肌动蛋白(Actin)的转录本数较多,分别为127个和54个。发现1个飞行蛋白Flightin编码基因(可编码一个长152 aa的蛋白),在该蛋白中检测到6个模体结构(Motif),膜翅目昆虫中在Motif 1的一些位点上其氨基酸类型表现出明显的特异性。在楚雄腮扁叶蜂中筛选到了25个飞行能量代谢关键酶编码基因,并基于这些酶构建了三条飞行能量代谢途径,即糖酵解(涉及15种酶)、脂肪氧化(涉及6种酶)和脯氨酸氧化(涉及4种酶)。在楚雄腮扁叶蜂中发现4个3-磷酸甘油脱氢酶GPDH异构体,但并未在这些异构体中找到类似果蝇飞行肌GPDH异构体所具有...