The fate and possible role of arylphorin during the metamorphosis of Mamestra brassicae.

1. Arylphorin, one of the storage proteins has been isolated from the hemolymph of Mamestra brassicae. 2. It has been established that Mamestra arylphorin is the most similar to manducin from among the known storage proteins of other species. 3. A rabbit polyclonal antibody has been developed against arylphorin, and its concentration changes have been determined quantitatively by ELISA in the hemolymph and fat body from the 1st day of the last larval instar to the 3rd day of the imago stage. 4. Histological sections were made on each day during the investigated period and it was shown by immunohistochemical methods that the main quantity of arylphorin was accumulated in the storage protein granules of the fat body and it could be detected even in the imaginal fat body. 5. The uptake of arylphorin by the fat body is induced by 20-hydroxyecdysone. 6. During differentiation of the imaginal cuticle arylphorin is incorporated first in the epidermal cells and it is built in the endocuticular layer of the integument thereafter.     

意大利蜜蜂工蜂脂肪体胚后发育过程中细胞的增殖和凋亡

脂肪体是昆虫体内物质贮备和中间代谢的重要组织。本研究通过显微形态观察、 BrdU免疫组织化学和原位末端转移酶标记(TUNEL)细胞凋亡检测技术, 对意大利蜜蜂Apis mellifera ligustica工蜂脂肪体胚后发育过程中细胞的增殖和凋亡特点进行了比较研究。结果表明： 意大利蜜蜂工蜂脂肪体细胞数量的快速增加集中在幼虫发育前期（1-3龄）, 而细胞的凋亡则集中在蛹发育早期的2-3 d（预蛹-2日龄蛹）时间之内。在变态发育中, 工蜂幼虫脂肪体凋亡降解后重新组建形成成虫的脂肪体。本研究为昆虫脂肪体的功能研究以及昆虫组织细胞自噬和凋亡的机制研究提供一定的证据。     

Feeding behaviour of the ladybeetle,Pseudoscymnus kurohime

A laboratory study was made of the feeding behaviour of the ladybeetlePseudoscymnus kurohime (Miyatake) when attacking the sugar cane woolly aphidCeratovacuna lanigera Zehntner. The 1st-instar ladybeetle larva was smaller than the 1st instar aphid nymph. All larval stages of the ladybeetle sucked out the body fluids of aphids and left their emptied corpses. The 1st, 2nd, and 3rd instar ladybeetle larvae mostly attacked 1st instar aphids, whereas the 4th-instar ladybeetle larvae attacked all stages of aphids. Ladybeetle adults ate mostly 1st-instar aphids. Young larvae attacked aphids in several different ways: (1) They crawled under an aphid, seized it by its underside and lifted it up. (2) They attacked new born nymphs at birth or shortly afterwards. (3) They fed on an aphid that had been captured by an older larva. The larvae preferred to seize with their mandibles the head or thorax of an aphid, while adults seized their prey by the abdomen. When attacked by an adult, 82% of the aphids secreted droplets from their abdominal cornicles, whereas only 7.2–12% secreted droplets when attacked by larvae. The 4th instar larvae more voracious than the younger larvae.     

20-Hydroxyecdysone mediated activation of larval haemolymph protein uptake by fat body cells of Corcyra cephalonica (Insecta)

Evidence is presented here to show that 20-hydroxyecdysone is essential for the activation of the larval fat body for differential uptake of larval haemolymph proteins (LHPs). By using radiolabelled LHPs it is shown that the fat body cells of Corcyra cephalonica selectively incorporate LHPs during late-larval and prepupal development. Fluorographic analysis of the labelled fat body proteins from prepupal stage separated on sodium dodecyl-sulphate polyacrylamide gels suggests that the LHPs are sequestered without any degradation. Although, during the last larval instar the uptake of all the three LHPs (LHP 1, LHP 2 and LHP 3) by the fat body cells is very low, 20-hydroxyecdysone treatment of early, mid or late-last instars causes a significant increase in uptake of all the three LHPs. However, the response to hormone treatment was more pronounced in late-last instar when compared to early and mid-last instar.     

Timing and ecdysteroid regulation of the molt in last instar greenhouse whiteflies (Trialeurodes vaporariorum)

A system of markers has been devised to track the development of 3rd and 4th instar/pharate adult greenhouse whiteflies. Instars were identified based on measurements of body width and body length. Depending upon the host plant, the product of the two measurements was exceptionally useful in distinguishing between instars. Body depth was used to divide the 3rd instar into eight stages and body depth and color and appearance of the developing adult eye were used to divide the 4th instar/pharate adult into nine stages. Under conditions of L:D 16:8 and a temperature of 26±2°C, the body depth of 3rd instars reared on greenbean increased from 0.025 (stage 1) to 0.2 mm (stage 8) and the instar duration was approximately 3 days. The body depth of 4th instars increased from approximately 0.1±0.02 (Stage 1) to 0.3±0.03 mm (Stage 5) and then remained constant or decreased slightly during adult development. Ecdysteroid titers peaked at approximately 120 fg/μg protein during Stages 3 through 6 of the 4th instar. Based on an external examination of developing 4th instars and the fluctuations in ecdysteroid titer, it appears that adult development is initiated in Stage 4 or 5 4th instars. Results from histological studies support this view. In Stage 4 nymphs, a subtle change was observed in the corneagenous cells of the eye. However, most Stage 4 4th instars possessed wing development characteristic of earlier, immature stages. In all Stage 5 insects, wing development had been initiated and the corneagenous cells had become quite distinct. In Stage 6 whiteflies, the wing buds were deeply folded and by Stage 7, spines were observed on the new cuticle, indicating that the adult cuticle was well-formed by this stage. Our study is the first to investigate the timing and regulation of the molt, to monitor ecdysteroid titers in precisely staged 4th instar whiteflies and to examine the internal anatomical changes associated with metamorphosis in these tiny homopteran insects.     

Growth and development of Encarsia formosa (Hymenoptera: Aphelinidae) in the greenhouse whitefly, Trialeurodes vaporariorum (Homoptera: Aleyrodidae): effect of host age

The tiny parasitoid wasp, Encarsia formosa, has been used successfully to control greenhouse whiteflies (GHWFs) in greenhouses in many countries throughout the world. Therefore, there has been considerable interest in developing methods for artificially rearing this wasp. However, little information is available concerning the regulation of its development including the host-parasitoid interactions that are required for the parasitoid to complete its life cycle. Here we confirm that parasitoid developmental rates differ significantly based upon the host instar parasitized. Development was faster when 3rd and 4th instar GHWFs were offered for parasitization than when 1st or 2nd instars were used. Our results show that it is primarily the embryo and the first two parasitoid instars that exhibit prolonged developmental times when 1st and 2nd instar whiteflies are parasitized. Although percent emergence was not affected by host age at the time of parasitization, adult longevity as well as adult emergence pattern varied greatly depending upon the instar parasitized. When 3rd and 4th instar GHWFs were selected for oviposition, adult wasps lived significantly longer than when 1st or 2nd instars were used; also, there was a sharp emergence peak on the 2nd day after emergence was first observed (reduced or absent when 1st or 2nd instar GHWFs were parasitized) and the emergence period was reduced from between 8 and 11 days to 5 days. In general, the younger the host instar parasitized, the less synchronous was parasitoid development. Previous reports that E. formosa will not molt to the 2nd instar until the host has reached its 4th instar were not confirmed. When 1st instar host nymphs were parasitized, 2nd instar parasitoids were detected in 3rd instar hosts. Importantly, however, no matter which instar was parasitized, the parasitoid never molted to its last instar until the host had reached Stage 5 of its last instar, a stage in which host pharate adult formation has been initiated. It appears, then, that a condition(s) associated with host pharate adult formation is required for the parasitoid's final larval molt. Results reported here should facilitate the development of in vitro rearing systems for E. formosa.     

茶黑刺粉虱蛹和卵的发育分级及与其防治适期的相关性

20 0 0年 4～ 6月 ,每 5日在皖南黑刺粉虱Aleurocanthusspiniferus(Quaintance)常发茶园中以平行跳跃法选 5 0个样方。每样方为 1m茶行 ,查其上、中、下层各 2片成叶上各虫态粉虱的数量 ;采回 2 0 0头蛹于立体显微镜下解剖。越冬代蛹期 32～ 38d。据蛹体形态和颜色的显著变化而分为 4级 :体液乳白色( 1 2～ 1 4d)、体液淡黄色 ( 6～ 8d)、体液橙红色 ( 1 1～ 1 2d)和体液淡紫色阶段 ( 3～ 4d)。引入该粉虱于盆载茶苗上 ,观察其生物学习性。第 1代卵期 2 2～ 2 8d ,据卵颜色的显著变化分为 4级 :乳白色 ( 2～ 4d)、淡黄色 ( 2～ 3d)、橙红色 ( 1 5～ 1 7d)和紫黑色阶段 ( 3～ 4d)。第 1代幼虫期 2 5～ 2 8d ,其中 1龄 9～ 1 2d ,2龄 9d ,3龄 7d ,蛹期 7～ 8d。越冬代成虫盛期和第 1代 1龄盛期为防治适期 ,可较好地用蛹或卵的分龄分级法预测。越冬代蛹全部羽化之时 ,又恰是 1龄幼虫盛期 ,易于掌握     

角倍蚜各虫态蜡腺的分布与结构

[目的]角倍蚜Schlechtendalia chinensis是五倍子的主要生产种,具有复杂的生活史,需要经历干母、干雌、秋迁蚜、越冬若蚜、春迁蚜和性蚜6种虫态,在盐肤木Rhus chinensis和藓类植物上转主寄生,经历有性和无性生殖、瘿内和瘿外世代的交替才能完成生活史.通过对角倍蚜蜡腺的研究,有助于深入了解角倍...     

可疑柄瘤蚜茧蜂对高温下不同龄期黑豆蚜的寄生及其适合度表现

研究寄生蜂对寄主不同龄期的寄生策略通常采用适温下（≈25℃）培养的寄主进行试验。 为探究蚜茧蜂对高温下生长的寄主蚜虫的寄生反应及其适合度表现,在30℃条件下饲养寄主孤雌胎生无翅黑豆蚜Aphis fabae Scopli,获得不同龄期若蚜和刚羽化的成蚜,分别提供给可疑柄瘤蚜茧蜂Lysiphlebus ambiguous Haliday寄生,观察蚜茧蜂的寄生率以及后代性比、体型大小和发育时间等适合度相关特性。结果表明： 可疑柄瘤蚜茧蜂对1至4龄若蚜及成蚜均寄生,但偏向寄生较早龄期的若蚜,对成蚜的寄生率为28.0％,显著低于对1龄（400％）和2龄（42.8%）寄主若蚜的寄生率。后代雌蜂比例和体型随寄主龄期（体型）增大而减小,而发育历期则呈现“中间低,两头高”的格局。后代性比、体型大小及发育历期等适合度表现与此前适温（≈25℃）下得到的结果截然相反。因此推测,寄主黑豆蚜体型或龄期可能不是或不全部是可疑柄瘤蚜茧蜂评价寄主质量的依据,其他与寄主蚜虫内共生菌动态相关的线索（如行为的,化学的等）可能才是其评价寄主质量的依据。     

日本柄瘤蚜茧蜂与其寄主豆蚜的相互作用：寄主龄期选择及其对发育的影响

在25℃下研究了日本柄瘤蚜茧蜂Lysiphlebus japonicus Ashmead对寄主豆蚜Aphis craccivora Koch龄期的选择和被寄生豆蚜的龄期对蚜茧蜂发育的影响。结果表明：在混合虫态寄主中,日本柄瘤蚜茧蜂通常选择较小龄期的若蚜寄生,其中2龄若蚜的相对被寄生率最高,为26.4%;其次是1龄若蚜,为20.6%;无翅成蚜与3、4龄有翅若蚜和成蚜的相对被寄生率较低。日本柄瘤蚜茧蜂的寄生延长了豆蚜若蚜的发育,其中1龄若蚜被寄生后,１～３龄历期显著延长;有翅3龄若蚜被寄生后,３、４龄历期明显延长;但无翅和有翅4龄若蚜被寄生后的发育历期均不受影响。各龄若蚜被寄生后羽化的成蚜寿命明显缩短,其中,被寄生的1龄若蚜不能发育至成蚜,其它较早龄期被寄生的若蚜羽化的成蚜繁殖力均显著降低。寄生时寄主的发育期也影响寄生蜂的发育,2龄豆蚜被寄生时的日本柄瘤蚜茧蜂个体发育最快,为194.10 h;1龄寄主被寄生时蚜茧蜂的发育最慢,需215.80 h。并对不同发育期蚜虫总蛋白质和总糖原含量进行了测定。     

Synthesis of the same two proteins prior to larval diapause and pupation in the spruce budworm,Choristoneura fumiferana

Spruce budworm larvae produce large quantities of two proteins (Choristoneura fumiferana diapause associated proteins 1 and 2, CfDAP1 and CfDAP2) that are diapause related. These proteins appeared soon after hatching and increased in abundance, reaching maximum levels by four days into the 1st instar, and they remained at high levels until three days after the termination of diapause. These two proteins were purified to homogeneity and their NH2-terminal sequences were obtained. Oligonucleotide primers designed on the basis of these NH2-terminal sequences were used in RT-PCR to isolate the cDNA fragments coding for these proteins. These PCR fragments were then used as probes to isolate the cDNAs that contained the complete coding region. The 2.5kb mRNAs coding for these proteins started to appear 24hr after hatching and large quantities of these mRNAs were detected in 1st instar and 2nd instar larvae until the 2nd instar larvae entered diapause. Low levels of these mRNAs were detected in the 2nd instar larvae that were preparing to enter diapause, in those that were in diapause as well as in those that terminated diapause. Low levels of CfDAP1 mRNA were also detected on days 1 and 2 after ecdysis to the 3rd instar. However, no CfDAP1 and CfDAP2 mRNAs could be detected during the 4th and 5th instar larval stages. The mRNAs reappeared 24hr after the 5th instar larvae molted into the 6th instar and increased to reach maximum levels by 60hr after ecdysis. The mRNA levels remained high until 156hr after ecdysis into the 6th instar (36-48hr before pupal ecdysis), after which they disappeared once again. Immunocytochemical analyses showed that CfDAP1 protein was present in 2nd and 6th instar larval fat body but not in 5th instar larval fat body. Thus, the same two genes were expressed for the first time before C. fumiferana larvae entered diapause and for a 2nd time before pupation.     

Quantitative changes and synthesis of cyanoprotein in whole body and tissues during development of the bean bug,Riptortus clavatus

Changes in biliverdin-binding cyanoprotein content in whole body and tissue extracts during development of nymphal and adult (non-diapause) bean bugs, Riptortus clavatus were analyzed by rocket immunoelectrophoresis (RIE). RIE using anti-CPegg serum can be used to determine the content of CP-A (Cp-1, 2 and 3) and CP-B (CP-4) separately. During the nymphal stage CP content of whole body changes cyclically in each instar. In the first nymphal instar, CPegg is the main CP which disappears during the first-second instar ecdysis. In nymphal bugs from the 2nd to 4th instars only CP-B (CP-4) is detected, and at the beginning of each instar the CP content is very low but increases toward the next ecdysis, after which CP decreases and disappears very rapidly. In the 5th nymphal instar, CP-B is the major CP but CP-A (CP-1, 2 and 3) is also detected. These changes in whole body CP content of 5th instar nymphs are observed in both females and males. The content of total CPs in the 5th instar nymph reaches about 1000 μg in the whole insect. During nymphal-adult ecdysis, nymphal CPs decrease and disappear at day 2 after emergence. In female adults CP-A (CP-1 only) increases rapidly after day 4 of adult emergence, while no CP is detected in male adults. In females CPs were detected only in the fat body, hemolymph and ovary. In the mid-5th-instar nymphs, CPs (CP-A and B) are mainly distributed in the hemolymph. CPs in the Hemolymph decrease during nymphal-adult ecdysis, whereas they increase in the fat body. CPs disappear from both the hemolymph and fat body by 2 days after ecdysis. Subsequently in the adult stage only CP-A increases again in the fat body and ovary. By tracer experiments using [³⁵S]-methionine, the fat body was shown to be the site of CP synthesis. CP-A and B synthetic activity was detected in nymphal females whereas, only CP-A synthesis was observed in adult females, while no CP synthesis was seen in adult males.     

Development of the hair mechanosensilla on the pupal labial palp of the butterfly,Pieris rapae L. (Lepidoptera : Pieridae)

Structure and ontogeny of the hair mechanosensilla on the distal segment of the pupal labial palp of Pieris rapae (Lepidoptera : Pieridae) were investigated in 7 successive stages between 28 hr after pupation and emergence of the imago. There are 7–8 mechanosensilla in the distal region of each palp in both sexes. These sensilla house a single sensory cell characterized by a tubular body, and 3 enveloping cells.At 28 hr after pupation, the anlagen of the hair mechanosensila are visible. Consecutive steps in the formation of the sensilla are: (1) elongation of the outer dendritic segment and of the dendritic sheath; (2) outgrowth of the trichogen cell and cuticle deposition; (3) increase in the diameter of the dendritic outer segment and in the number of microtubules within it; (4) reduction of the distal part of the dendritic outer segment and formation of the tubular body; (5) folding of the membrane of the dendritic outer segment and appearance of the receptor lymph cavity.The tubular body is formed during a period of about 80 hr. Its earliest appearance comprises groups of 3–4 microtubules, which are connected by electron-dense material. The final dense tubular body develops via microtubules linked together by electron-dense material.     

Larval anatomy and structure of absorbing epithelia in the aphid parasitoid Aphidius ervi Haliday (Hymenoptera, Braconidae)

The present work describes Aphidius ervi Haliday (Hymenoptera, Braconidae) larval anatomy and development, focusing on time-related changes of body structure and cell ultrastructure, especially of the epithelial layers involved in nutrient absorption. Newly hatched 1st instar larvae of A. ervi are characterised by gut absence and a compact cluster of cells makes up their body. As the parasitoid larva develops, the central undifferentiated cell mass becomes hollowed out, leading to the formation of gut anlage. This suggests that absorption of nutrients at that stage may take place through the body surface, as more directly demonstrated by the occurrence on the epidermis of proteins associated with transepithelial transport, such as Na(+)/K(+)-ATPase and alkaline phosphatase (ALP). Second instar larvae show the presence of the gut with a well-differentiated brush border and a peritrophic membrane. Gut cells are filled by masses of glycogen granules and lipid droplets. The tracheal system starts to be visible. The haemocoel becomes evident in late 2nd instar, and contains large silk glands. Mature 3rd instar larvae are typically hymenopteriform. The midgut accounts for most of the body volume and is actively involved in nutrient absorption, as indicated by the well developed brush border and by the presence of Na(+)/K(+)-ATPase and ALP on the basolateral and luminal membrane respectively. At this stage, large lipid droplets have gradually replaced the cellular glycogen stores in the midgut cells. The tracheae are completely differentiated, but their internal lumen still contains fibrillar material, suggesting that they are not functional as long as host fluids bath the parasitoid larva. In late 3rd instar larvae, silk glands, structurally similar to Malpighian tubules, show a very intense vesicular traffic toward the internal lumen, which, eventually, results in being filled by secretion products, suggesting the possible recycling of metabolic waste products during mummy formation.     

敲减神经肽F基因(npf)对亚洲玉米螟取食、生长发育和繁殖的影响

【目的】神经肽F(neuropeptide F, NPF)是无脊椎动物特有的一类神经肽,因其C末端是苯丙氨酸(F)而命名,参与昆虫的取食、生物节律、学习记忆等多种生理功能的调控。本研究旨在明确NPF对亚洲玉米螟Ostrinia furnacalis生长发育的影响,为害虫防治提供重要依据。【方法】采用一种基于工程菌高效合成靶向昆虫基因的dsRNA的方法经济有效地敲降npf,用低浓度(0.01%)和高浓度(0.02%)dsNPF和dsGFP(对照)分别饲喂亚洲玉米螟1龄初、3龄初和5龄初幼虫直至化蛹,检测5龄幼虫平均取食量、体重、体长、存活率和化蛹率,蛹羽化率和成虫产卵量,以及幼虫各龄期、蛹发育历期和成虫寿命。【结果】从亚洲玉米螟1, 3和5龄初幼虫开始饲喂0.01%和0.02% dsNPF时,与饲喂相应浓度dsGFP的对照相比,除个别点外,5龄幼虫的取食量、体重、体长、存活率和化蛹率,蛹羽化率和成虫单雌产卵量均显著降低,幼虫各龄期、蛹发育历期均显著延长,成虫寿命显著缩短。且dsNPF处理幼虫的龄期越早对发育的影响越大。其中0.01% dsNPF处理的1龄幼虫和0.02% dsNPF处理的3龄幼虫有90%的个体在蛹期死亡,而0.02%dsNPF处理的1龄幼虫有90%的个体在幼虫期死亡。【结论】结果提示NPF对亚洲玉米螟的发育和取食具有调控作用,这为探索新型绿色的害虫防治提供了依据。     

Postembryonic development of the complex tibial organ in the foreleg of the bushcricket Ephippiger ephippiger (Orthoptera,Tettigoniidae)

Summary The postembryonic development of the morphology and anatomy of the complex tibial organ in the foreleg of the bushcricket Ephippiger ephippiger is described. All the receptor cells are present in the subgenual organ, the intermediate organ and the crista acustica in the 1st larval instar. Generally, even in the 1st instar, the arrangement of the scolopidia in the three organs resembles the adult structure. The acoustic trachea, the tympana, the tympanal covers and the acoustic spiracle develop step by step in subsequent instars. The acoustic trachea resembles the adult structure for the first time in the 4th instar, although its volume is still small. The auditory threshold curves recorded from the tympanal nerve in instars 4, 5 and 6 show the same frequency maxima as those in the adult. The overall sensitivity significantly increases after the final moult. The dimensions of structures that lie within the crista acustica and that are probably involved in stimulus transduction and in frequency tuning have been analysed. The dorsal wall of the anterior trachea, the tectorial membrane and the cap cells have similar dimensions, especially in the last three instars and in adults.     

Specific developmental window for establishment of an insect-microbe gut symbiosis

The alydid stinkbug Riptortus pedestris is specifically associated with a beneficial Burkholderia symbiont in the midgut crypts. Exceptional among insect-microbe mutualistic associations, the Burkholderia symbiont is not vertically transmitted but orally acquired by nymphal insects from the environment every generation. Here we experimentally investigated the process of symbiont acquisition during the nymphal development of R. pedestris. In a field population, many 2nd instar nymphs were Burkholderia free, while all 3rd, 4th, and 5th instar nymphs were infected. When reared on soil-grown potted soybean plants, Burkholderia acquisition occurred at a drastically higher frequency in the 2nd instar than in the other instars. Oral administration of cultured Burkholderia cells showed that 2nd and 3rd instar nymphs are significantly more susceptible to the symbiont infection than 1st, 4th, and 5th instar nymphs. Histological observations revealed rudimentary midgut crypts in the 1st instar, in contrast to well-developed midgut crypts in the 2nd and later instars. These results indicate that R. pedestris acquires the Burkholderia symbiont from the environment mainly during the 2nd instar period and strongly suggest that the competence for the symbiont infection is developmentally regulated by the host side. Potential mechanisms involved in infection competence and possible reasons why the infection preferentially occurs in the 2nd instar are discussed.     

胚后发育期臭腹腺蝗中的血细胞种类

应用血球计数器统计了胚后发育期臭腹腺蝗Zonocerus variegatus中存在的血细胞类型和数目。从1龄幼虫至成虫的发育阶段中共观察到6种血细胞类型,即原血细胞 （PRS）、 浆血细胞 （PLS）、粒细胞 （GRS）、珠血细胞 （SPS）、绛色细胞（OES） 和adipohaemocytes （ADS）。不过,在1龄幼虫期未发现OES。在这6种血细胞中,PLS的总平均数最高,OES的总平均数最低。成虫期的血细胞数目显著高于其他发育阶段（P<0.05）,而1龄幼虫和2龄幼虫期的血细胞数目不存在显著差异（P>0.05）。     

Developmental and sex-dependent regulation of storage protein synthesis in the silkworm,Bombyx mori

The mechanism of sex-dependent expression of a major plasma protein, referred to as storage protein 1 (SP-1) was studied during development of the silkworm, Bombyx mori. SP-1 occurred in the hemolymph of the female as well as in the male larvae until the end of the fourth larval instar. In the last instar larvae, the amount of SP-1 in the hemolymph greatly increased in females, but markedly declined in males. The level of fat body mRNA for SP-1 reflected the developmental and sex-dependent changes in the hemolymph concentration of SP-1. The developmental patterns of hemolymph proteins in the third and the fourth instar larvae of sex-mosaic individuals were quite analogous to those observed in normal larvae at the same developmental stages. The hemolymph concentration of SP-1 at the last larval instar of the sex mosaics varied among individuals irrespective of the gonad compositions. In vitro culture of the fat body cells dissected from several locations of a sex-mosaic larva provided evidence that each fat body cell in a common hemolymph milieu synthesizes a high (female type) or a low (male type) level of SP-1 depending on the sex chromosome composition. The amount of vitellogenin in the hemolymph of the sex-mosaic pupae was in proportion to that of SP-1 at the last larval instar. From these results, it is suggested that the sex-dependent expression of SP-1 and vitellogenin in B. mori is genetically determined and developmentally regulated without participation of the reproductive organs or any sex-specific humoral factors.     

Properties,synthesis, and accumulation of storage proteins in Pieris rapae L.

Two kinds of storage proteins (SP-1, SP-2) were confirmed in hemolymph and fat body of Pieris rapae during metamorphosis. Both proteins were present in high concentrations in the hemolymph during the last larval instar. Hemolymph concentrations of SP-1 and SP-2 dropped after pupation as the proteins were being deposited in fat bodies. SP-2 is present in a larger amount than SP-1. Detailed studies on storage proteins determined their properties, mode of synthesis, and accumulation in the fat body. SP-1 has a molecular weight of 500,000 and consists of one type of subunit (M_r 77,000), while SP-2 has a molecular weight of 460,000 and is composed of two types of subunits (M_r 80,000 and 69,000). The pl values of SP-1 and SP-2 were determined to be 6.97 and 7.06, respectively. Fat body cells from 1-day-old fifth instar larvae synthesized storage proteins in large amounts, whereas those from late prepupae exhibited high protein sequestration. Proteins taken up in fat body accumulated in dense granules during the pupal stage but sharply decreased at the adult stage. Morphological changes in the fat body tissues were observed during the larval-pupal transformation; the nuclei of fat body cells became irregularly shaped, and the boundaries between cells seemed to be obscure. Synthesis, storage, or degradation of storage proteins in fat body during development is closely associated with morphological changes in the tissues.