Vitellogenesis and oocyte development in azadirachtin-induced fifth-instar overage nymphs of Locusta migratoria (L.)

Injection of azadirachtin into females of Locusta migratoria at the beginning of the last nymphal instar prevented molting to the adult stage, and many of these locusts survived for long periods as overage fifth-instar nymphs. Overage female nymphs synthesized vitellogenin; maximum vitellogenin content in their hemolymph was 6–7 times higher than that found in normal adult females. The overage female nymphs developed vitellogenic oocytes, but development was retarded to some extent: although vitellogenin did accumulate in the proximal oocytes, their maximum average length was only about 2.8 mm (compared to 6.2 mm in normal adult females) and extensive oocyte resorption was observed. Thus, attainment of adult competence of the organs and processes involved in female reproduction is independent to a considerable extent from the process of overt adult morphogenesis.     

Flight fuel related differences between solitary and gregarious locusts (Locusta migratoria migratorioides)

Abstract. Flight fuel relations of crowded and isolated Locusta migratoria migratorioides were investigated in younger (12–16 days after fledging) and older (27–30 or 27–32 days after fledging) adult males.No phase polymorphism dependent differences were found in resting haemolymph carbohydrate levels of the younger locusts.In the older age group, resting haemolymph carbohydrate levels were slightly though significantly higher in the isolated than in the crowded locusts.Injection of various doses of synthetic adipokinetic hormones (AKHs) did not induce marked changes in haemolymph carbohydrate levels and no differences were found between crowded and isolated locusts.A 30 min flight led to the same decrease in haemolymph carbohydrate levels of isolated and crowded locusts, 43.3% and 44.6% of the resting levels, respectively.We concluded, therefore, that the results do not seem to indicate that isolated locusts rely more heavily on carbohydrates as flight fuel than crowded locusts.Hyperlipaemic responses to flight were less intense in isolated than in crowded locusts, but phase polymorphism dependent differences in flight-induced increase of haemolymph lipid levels were not parallel in 12–16-day-old and 27–32-day-old males.In the younger age group the difference was mainly in the duration of flight needed to induce full response which appeared already after 20 min of flight in the crowded locusts, but only after 45 or 60 min of flight in the isolated ones.In contrast, the older isolated locusts showed markedly lower haemolymph lipid elevations than the crowded locusts even after 30, 45 or 60 min of flight.The hypothesis is forwarded that isolated locusts have a rather coarse adipokinetic strategy focused on a single long-distance migratory flight, whereas gregarious locusts possess a fine adipokinetic balance for reiterative migratory flights and saving fuel reserves for unpredictable long-distance migrations.     

Muscle activity underlying sexual behaviour in male locusts (Locusta migratoria) after normal and hormonally disturbed development

Abstract. . The activities of three sets of muscles, representing the major components of the abdominal muscle system, were recorded in the pregenital abdominal segments of adult males of Locusta migratoria. The muscular activities were associated with three consecutive actions of the male's mating behaviour: abdominal lowering, S-bending and hooking-up. These three actions depend mainly on the relative coordination of the dorsal versus ventral longitudinal muscles; the activity of the dorsoventral muscles is rather unpredictable, except in the sixth and seventh abdominal segments where they are regularly involved in hooking-up. Studies on male sexual behaviour-linked muscle activity in precocene-induced fifth-instar adultiforms and azadirachtin-induced fifth-instar over-aged nymphs revealed no distinct differences between these creatures and normal mature males. Therefore the muscle activities associated with these adult-specific behavioural acts can be released precociously, i.e. their occurrence is not dependent on a distinct series of instars. Moreover, the results obtained with over-aged nymphs demonstrate that morphogenesis and ethogenesis (i.e. formation of neural circuits controlling adult-specific behaviour) are not closely dependent on each other.     

东亚飞蝗Locusta migratoria manilensis（Mey．）膝下器中具橛感器的附属细胞和附属结构的超微结构

东亚飞蝗膝下器的具橛感器主要由三类细胞组成．即：感觉细胞、感橛细胞和冠细胞。感觉细胞为具橛感器的主要结构和功能细胞,其超微结构已在其他的文章中描述。感橛细胞是具橛感器的主要支持细胞,从近端到远端依次与神经胶质细胞、感觉细胞的远端树突部分和感觉纤毛部以及顶端细胞外结构——冠、冠细胞直接接触．感橛细胞内最明显的结构为感概,另外,感橛细胞质被高度“空化”。冠细胞紧密包围着感橛细胞和冠,冠细胞中含有大量的纵行微管．并将整个具橛感器连接到体壁上。     

短时高温暴露下东亚飞蝗雌虫血淋巴蛋白表达分析及质谱鉴定

为研究短时高温对东亚飞蝗Locusta migratoria manilensis Meyen血淋巴蛋白的影响,采用Bradford法、SDSPAGE电泳和质谱等方法,对东亚飞蝗雌虫血淋巴样品进行检测。结果表明:短时高温对血淋巴蛋白含量有显著影响(P0.01),36℃-42℃范围内,随温度升高,血淋巴蛋白浓度亦升高,其中39℃、42℃处理组与对照组差异显著(P0.01);短时高温对血淋巴蛋白种类存在一定影响,对照组雌虫血淋巴中存在11种蛋白,高温处理后,4种蛋白含量逐渐增加,6种蛋白含量没有明显变化,1种蛋白消失;经质谱检测,鉴定了5种蛋白,分别为载脂蛋白前体、酚氧化酶原、2个储存蛋白和19 kDa血淋巴蛋白,另外6条蛋白未被鉴定。推测载脂蛋白前体、酚氧化酶原、储存蛋白在东亚飞蝗应对高温胁迫过程中发挥重要作用。     

气候变暖背景下新疆和中哈边境亚洲飞蝗适生区预测及变化

亚洲飞蝗Locusta migratoria migratoria是中国新疆与哈萨克斯坦边境区域重要害虫之一,具迁飞性且繁殖能力强,对农牧业经济造成巨大伤害。本文以亚洲飞蝗为研究对象,根据其发生区和相关生物学特性,利用CLIMEX 4.0.2和ArcGIS 10.2相结合,预测其在新疆和中哈边境区域亚洲飞蝗的潜在地理分布。亚洲飞蝗的适生区在新疆境内集中分布在北疆(42.69～48.29°N),包括伊犁、博尔塔拉中部、塔城西北部及南部、阿勒泰西部、昌吉和乌鲁木齐南部地区;哈萨克斯坦境内主要分布在北纬47.03～51.65°N区域,包括东哈萨克斯坦州北部、阿拉木图州东南部境内的湖泊及河流沿岸地区,这与亚洲飞蝗的现有分布点和历史发生记录吻合。未来气候变暖情景下,亚洲飞蝗在中哈边境新疆境内的适生区逐渐扩大,其中在阿勒泰、伊犁、昌吉及乌鲁木齐的高度适生区面积增加,哈密开始出现高度适生区;在哈萨克斯坦边境区域的适生区略有增加,其中东哈萨克斯坦州地区高度适生区面积减少明显。研究结果对区域内亚洲飞蝗的预测预报和综合防控具有重要意义。     

Optimization of parental RNAi conditions for hunchback gene in Locusta migratoria manilensis (Meyen)

An investigation on the optimization of parental RNA interference (RNAi) conditionsfor hunchback {hb) gene in Locusta migratoria manilensis (Meyen) was conducted.Double stranded RNA (dsRNA) corresponding to hb gene was injected into haemocoel offemale adults of L.migratoria manilensis.Embryos developed from the eggs laid by theinjected adults on the 7th day after eclosion showed observable effects of RNAi for hb.Thesilencing effect after delivery treatment of dsRNA for hb gene was maintained for moretha...     

白洋淀东亚飞蝗持续大发生浅析

进入 90年代以来 ,白洋淀蝗区东亚飞蝗Locustamigratoriamanilensis(Meyen)持续大发生 4次 ,是50年来十分罕见的。究其原因 ,主要受白洋淀水位变化的影响 ,其中 8月水位的高低直接影响翌年夏蝗发生程度 ,其次是生态环境和气候条件等因素的影响。     

Development of the tympanal organ in larvae of the migratory locust (Locusta migratoria)

Summary The tympanal organ of the migratory locust acquires its definitive form during larval development. All the receptor cells (90–100) are present in the 1st instar, whereas the differentiation of the tympanum and the cuticular structures it bears proceeds in steps from one instar to the next. The elevated process is the earliest such structure to appear (2nd instar); it is followed by the pyriform vesicle (3rd instar) and folded body (4th instar). The styliform body first appears in the imago. Although the typical arrangement of the receptor cells is already discernible in the 1st instar, some of the attachment sites change during development, the final configuration appearing only in the imago.Supported by the Deutsche Forschungsgemeinschaft (Ka 498/2)     

Effect of Paranosema locustae (Microsporidia) on the behavioural phases of Locusta migratoria (Orthoptera: Acrididae) in the laboratory

The ability of parasites to modify the behaviour of their hosts is a wide spread phenomenon, but the effects of microsporidian parasites on locust behaviour remain unexplored. Here the frequencies of directional changes (ND) and jumping (NJ) per minute of gregarious locusts infected with 2000 spores of the microsporidian parasite Paranosema locustae were significantly different from those of untreated locusts 10 and 16 days after infection, being similar to values for solitary nymphs. In contrast, the behaviour of locusts inoculated with the lower doses of 200 spores/locust was sometimes like that of solitary nymphs. At other times, behaviour was intermediate between solitary and gregarious, i.e. transitional. The rearing density did not affect the turning and jumping behaviour of infected locusts, and their behaviours were similar to those of solitary locusts at 10–16 days after infection. Our study demonstrates that infection with P. locustae may lead gregarious locusts to change some of their behaviour to that typical of solitary locusts.     

Protein production in components of the accessory gland complex of male Melanoplus sanguinipes (Insecta: Orthoptera)

Protein production during sexual maturation or after allatectomy (followed by juvenile hormone replacement therapy) has been examined in the long hyaline glands, short hyaline glands, white glands, and seminal vesicles, which make up the accessory gland complex of male Melanoplus sanguinipes. During maturation, the amount of protein in the long hyaline glands increases about 14-fold, and in each of the other components between 5- and 6-fold. Most protein accumulates between days 3 and 5, and this is reflected in high levels of incorporation of radiolabelled leucine in this period.

The components show differential sensitivity to the effects of allatectomy. After this operation, the protein content of, and incorporation of radiolabel into, the long hyaline glands remain near the day 0 level. In the white glands and short hyaline glands, allatectomy also has a marked, though less severe, effect on protein synthesis and accumulation. The seminal vesicles are least affected by allatectomy and continue to accumulate protein (though more slowly) to about 60% of the normal level by day 10. Juvenile hormone compounds applied topically to allatectomized insects on day 2 restored the ability of the gland components to accumulate proteins, though to differing degrees. JHI is the most effective compound, stimulating synthesis and accumulation of protein to near normal levels by day 10, whereas application of JHIII or Stauffer's synthetic JH led to only partial restoration of protein synthesis in the glands.     

Structure of male accessory glands of Bolivarius siculus (fischer) (Orthoptera,Tettigoniidae) and protein analysis of their secretions

In Tettigoniidae (Orthoptera), male reproductive accessory glands are involved in the construction of a two‐part spermatophore; one part, the spermatophylax, is devoid of sperm and considered a nuptial gift. The morphology, ultrastructure, and secretion protein content of the male reproductive accessory glands from Bolivarius siculus were investigated. Two main groups of gland tubules open into the ejaculatory duct: the “first‐order” glands, a number of large anterior tubules, and the “second‐order” glands, smaller and more numerous tubules positioned posteriorly. Along with a further subdivision of the gland tubules, we here describe for the first time an additional gland group, the intermediate tubules, which open between first and second‐order glands. The mesoderm‐derived epithelium of all glands is a single layer of microvillated cells, which can be either flattened or cylindric in the proximal or distal region of the same gland. Epithelial cells, very rich in RER and Golgi systems, produce secretions of both electron‐dense granules and globules or electron‐transparent material, discharged into the gland lumen by apocrine or merocrine mechanisms, respectively. With one exception, a unique electrophoresis protein profile was displayed by each of the gland types, paralleling their unique morphologies. To assess the contribution of different types of accessory glands to the construction of the spermatophore, the protein patterns of the gland secretions were compared with those of the extracts from the two parts of the spermatophore. All samples showed bands distributed in a wide range of molecular weight, including proteins of very low molecular mass. However, one major high molecular weight protein band (>180 kDa) is seen exclusively in extracts from the first‐order glands, and corresponds to an important protein component of the spermatophylax. J. Morphol., 2009. © 2009 Wiley‐Liss, Inc.     

Effects of temperature and [His7]-corazonin on the body darkening in Locusta migratoria

Abstract.  [His⁷]-corazonin is a neuropeptide that induces dark coloration in locusts. This study examined the effect of temperature on body colour in the migratory locust, Locusta migratoria . L. Injection of a low dose (1 pmol) of [His⁷]-corazonin caused albino nymphs to develop dark coloration at 25–34 °C, but little darkening occurred at 38 and 42 °C. However, injection of a high dose (10 pmol) induced darkening even at these high temperatures. Transfer of nymphs injected with 1 pmol of [His⁷]-corazonin from 30 to 42 °C, and vice versa, indicated that temperature influenced darkening at any time after injection. Measurements of the luminance of the pronotum were made using commercially available computer software to follow continuous changes in darkening of the body. The body colour of nymphs injected with [His⁷]-corazonin was reddish-brown at 25 °C, blackish at 30 and 34 °C, and greyish or whitish at 38 and 42 °C. High temperature also suppressed darkening in a normal (pigmented) strain. Most nymphs transferred from 30 to 42 °C during the first three stadia developed a light colour in the fifth stadium without the striking black patterns that are typically manifested in gregarious nymphs at lower temperatures. Such individuals developed black patterns in the fifth stadium when injected with [His⁷]-corazonin at a mid stage of the previous stadium. These results indicate that high temperature may induce light body coloration by suppressing the release of [His⁷]-corazonin in normal locusts.     

Localization of Lom-AG-myotropin I-like substances in the male reproductive and nervous tissue of the locust,Locusta migratoria

Summary Lom-AG myotropin I (Lom-AG-MTI) was the first peptide to be isolated from the male accessory reproductive glands of the locust, Locust migratoria. It shows no sequence similarity to any of the peptides identified from vertebrate or invertebrate tissues. A polyclonal antiserum was used to localize Lom-AG-MTI-like material in the male reproductive system and nervous system of the locust. Immunoreactivity was found in two of the hyaline gland tubules. In the brain, cell bodies were detected in the proto- and deuterocerebrum as well as the frontal ganglion. Nerve fibers were stained in the neuropils of the brain and throughout the labial nerves into the recurrent nerve. Thoracic and last abdominal ganglia contained neurons which could be stained with Lom-AG-MTI antiserum. The pronounced reactivity in the central nervous system suggests a possible neuroregulatory function of the peptide.     

Influence of soil moisture on egg cold hardiness in the migratory locust Locusta migratoria (Orthoptera: Acridiidae)

Abstract.  The present study investigates the influence of environmental moisture on cold hardiness of the migratory locust, Locusta migratoria . The water content of locust eggs kept in soil at 30 °C varies according to the moisture content of the substrate. In turn, it can significantly affect the supercooling point of locust eggs (range from −26 to −14.8 °C) and the mortality when exposed to subzero temperatures. Environmental moisture influences the supercooling capacity of eggs and their survival at low temperature. When locust eggs of the same water content are exposed to subzero temperatures under different soil moistures, their mortality varies between short-time exposure and long-time exposure at subzero temperatures. Given a short-time exposure, mortality in wet soil is lower than in dry soil due to the buffering effect of soil water against temperature change. The pattern of egg mortality is reversed after long-time exposure at low temperature, suggesting that inoculative freezing may be an important mortality factor. It is suggested that interactions between soil moisture and low temperature can influence the cold hardiness of locust eggs, and partial dehydration is beneficial to over-wintering eggs of the migratory locust.     

Ecdysteroids and meiotic reinitiation in Palaemon serratus (Crustacea Decapoda Natantia) and in Locusta migratoria (Insecta orthoptera). A comparative study

Summary

Meiotic reinitiation has been studied in Locusta migratoria and Palaemon serratus in relation to the titre of free ecdysteroids present in the maturing oocyte. In both species meiotic reinitiation is characterized by two meiotic arrests, in prophase I and in metaphase I, and the first meiotic resumption which leads to germinal vesicle breakdown (GVBD) is correlated with increasing titres of ecdysteroids in the oocyte. Meiotic reinitiation has been successfully triggered in the oocytes of both species by incubation with physiological doses of ecdysteroids.     

东亚飞蝗中肠几丁质酶基因的克隆、序列分析及组织定位

通过RACE方法,克隆了东亚飞蝗Locusta migratoria manilensis (Meyen)几丁质酶基因 (LmChi)cDNA全序列 (GenBank 登录号：EF092841)。获得的cDNA全长1 604 bp,其中可读框1 452 bp, 编码483个氨基酸。推测其氨基酸序列与18家族昆虫几丁质酶有较高的相似性。与其他几丁质酶一样,东亚飞蝗几丁质酶序列也包含一个信号肽、一个几丁质酶活性位点、一个碳端丝氨酸富集区和一个几丁质结合域。半定量RT-PCR研究表明,LmChi基因只在东亚飞蝗不同发育阶段的中肠组织中表达,而在东亚飞蝗体壁、前肠和后肠均没有发现LmChi基因的转录。     

Transfer and fate of male secretions deposited in the spermatophore of females of Acanthoscelides obtectus Say (Coleoptera Bruchidae)

During mating, males of Acanthoscelides obtectus deposit a spermatophore in the female genital tract. Spermatophore structure subsequently undergoes considerable modification, especially the central portion, which becomes vacuolated. Two methods were used to show that certain male secretions could thus pass into female haemolymph. When young males were injected with [¹⁴C]-arginine or [¹⁴C]-histidine, the accessory glands actively incorporated the isotope and the resulting spermatophores were radioactive. After mating, spermatophore radioactivity declined and then appeared in the haemolymph of females and in the oöcytes after a delay. Immunoelectrophoresis also showed that antigens appeared in the haemolymph of females after mating which reacted against male-gland antiserum. This technique, however, did not enable us to detect the presence of male antigens in the oöcytes formed after mating. The fate of some male secretions in the female and their physiological importance in the control of the female reproductive function were analysed in the present work.     

Age-specific energetics of reproduction in Nucula turgida (Leckenby and Marshall) a bivalve with lecithotrophic larval development

Summary

Nucula turgida is a protobranch bivalve of the shallow sublittoral which produces, for a bivalve, unusually large eggs with a high lipid content to sustain the lecithotrophic development of the larvae. Males and females have similar reproductive investments, and the most noticeable feature of their output is the proportional increase in reproductive output as the animals age. Reproduction, as a proportion of the assimilation (Rep/C), was around 0.17 at population level but ranged from 0.055 in the 3 + year class to 0.54 in the 7 + year class. Similarly, C(=1 ? [(A ? G/R]) where A is assimilation, G gonad production and R is respiration, which appeared to be almost perfectly balanced at population level (C= ?0.05) in fact varied from very conservative (C= ?1.63) at 3 + to very “reckless” at 7+ (C=0.57). Using age-specific data, more accurate estimates can be made of future recruitment, and by back-calculation the survival rate from spawning to appearance in the benthos can be calculated.