THE STRUCTURE OF INTERSEGMENTAL MUSCLE FIBERS IN AN INSECT, PERIPLANETA AMERICANA L

The organization of intersegmental muscle fibers associated with the dorsal abdominal sclerites of the cockroach is described. These fibers correspond closely, in the disposition and derivation of the membranes of the transverse tubular system and sarcoplasmic reticulum cisternae, with insect synchronous flight muscle fibers, but differ markedly from these in their fibrillar architecture and mitochondrial content. The mitochondria are small and generally aligned alongside the prominent I bands of the sarcomere, and, in the best-oriented profiles of the A bands, thick filaments are associated with orbitals of twelve thin filaments, a configuration that has also been observed in striated fibers of insect visceral muscle. These structural features of insect muscles are compared and discussed in terms of possible variations in the control of contraction and relaxation, and in the nature of their mechanical role.     

AN “INTERVAL TIMER” FOR THE PRODUCTION OF OVIPARAE IN APHIS RUBICOLA (HOMOPTERA: APHIDIDAE)

Post-fundatrix lineages of Aphis rubicola Oestlund exposed to continual short-day photoregimes of 8 or 10 h resisted sexual-promoting influences for varying lengths of time. Linages originating from fundatrices and continually exposed to short days lasted 18.5–31.5 days before consisting of 50% ovipara producers. When 13–67 16-h days preceded continual short-day exposure, lineages lasted 11.5–19 days before consisting of 50% ovipara producers. A short-lived interval timer for the production of oviparae was thus demonstrated.The timer expired gradually, not abruptly, so that the greater the distance was in days from the newly hatched fundatrix, the less was the time required for 50% of the adults to be ovipara producers (r=–0.892). Weakening in a curvilinear fashion, the timer lost its greates amount of resistance between the 5th and 13th days of deposition by fundatrices.

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Zusammenfassung Linien von Fundatrigenien von Aphis rubicola Oestlund, welche kontinuierlichem Kurztag von 8 rsp. 10 Stunden ausgesetzt wurden, widerstanden den die Bildung von Geschlechtstieren fördernden Einflüssen für verschiedenlange Zeit. Linien, welche ständig Kurztag ausgesetzt wurden, brauchten 18,5 bis 31,5 Tage, bis sie zu 50% aus Sexuparen bestanden. Wenn die Linien vorgängig für 26,5 bis 80,5 Tage Langtag (16 Stunden) ausgesetzt wurden, bevor sie zu Kurztag kamen, brauchte es 11,5 bis 19 Tage, bis 50% Sexupare waren. Damit wurde ein kurzlebiger Intervall-Zeitmesser für die Bildung von Geschlechtstieren nachgewiesen.Dieser Zeitmesser erlöscht allmählich in krummliniger Form und nicht plötzlich. Je grösser der zeitliche Abstand von der Junglarve der Fundatrix, um so kleiner war die erforderliche Zeit, bis 50% der Adulten Sexupare waren (n=–0,892).

     

CONTRACTION IN GLYCERINATED MYOFIBRILS OF AN INSECT (ORTHOPTERA, ACRIDIDAE)

The A substance of glycerol-treated myofibrils of the femoral muscles of the locust Gastrimargus musicus (Fabr.), removed by a salt solution of high ionic strength, has the properties of actomyosin. A phase contrast study of these fibrils, contracted by the addition of ATP, has revealed that the A bands of most myofibrils shorten during contraction. Changes in density within the A band lead to the formation of C_m and C_z bands while I bands are still present. The A band region between the contraction bands is of much lower density than it is in the uncontracted fibril. During contraction in some fibrils the I bands disappeared and the A bands remained unchanged in length until contraction bands appeared. These results have been interpreted in terms of coiling and stretching of the thick filaments of the sarcomere.     

The sensory systems and feeding behavior of leafhoppers. I. The aster leafhopper,Macrosteles fascifrons stål (homoptera,cicadellidae)

The ultrastructure of the sensilla, and other structures, within the stylets and precibarium of Macrosteles fascifrons were examined by transmission and scanning electron microscopy. Precibarium is a new term, defined here, for the canal that precedes the cibarium inside the leafhopper head. Within the precibarium are found 20 chemosensilla and a previously undescribed structure, the precibarial valve. Twelve mechanosensilla, three in each stylet, are found within the maxillary and mandibular stylets. The relationship between all of these structures and feeding by the insect is detailed in a feeding mechanism hypothesis. It is concluded that leafhoppers (and probably all homopterans) utilize the precibarial chemosensilla alone for gustatory discrimination, the stylet sensilla for proprioception, and the precibarial valve for regulation of fluid uptake and compartmentalization of the sensilla.     

北京地区51种蚜虫的染色体组型

本文报道了通过改进蚜虫染色体制片方法,对北京地区51种常见蚜虫的染色体进行研究的结果。在这51种蚜虫中,染色体数目范围由2n=4至2n=18,出现频率最高的为2n=8、10、12。根据染色体的长度和形态,总结出8种蚜虫染色体组型,并将这几种组型与两种蚜虫分类系统进行对照,在较高级的分类水平上,讨论了这二种分类系统安排与细胞学证据的相符程度。     

世界蚜虫分类研究进展

本文综述了世界蚜虫分类研究进展。内容包括形态分类、细胞分类、生物化学分类以及化石研究等,并以M.L.Sharma的文献目录为基础,对世界蚜虫分类研究报告篇数进行统计。结果表明:世界各国蚜虫分类研究进展极不平衡,美国、加拿大、日本及欧洲的一些国家包括荷兰、丹麦、瑞典、捷克、波兰、德国等其α分类任务基本完成,印度也进展较快,离完成α分类任务为期不远。苏联欧洲部分也已基本完成,亚洲部分和中国尚有大量α级分类工作有待完成。     

INNERVATION OF THE FIBRILLAR FLIGHT MUSCLE OF AN INSECT: TENEBRIO MOLITOR (COLEOPTERA)

The structure of peripheral nerves, and the organization of the myoneural junctions in flight muscle fibers of a beetle is described. The uniaxonal presynaptic nerve branches display the "tunicated" structure reported in the case of other insect nerves and the relationship between the axon and the lemnoblast folds is discussed. The synapsing nerve terminal shows many similarities with that of central and peripheral junctions of other insects and of vertebrates (e.g., the intra-axonal synaptic vesicles) but certain important differences have been noted between this region in Tenebrio flight muscle and in other insect muscles. Firstly, the axon discards the lemnoblast before the junction is established and the axon effects a circumferential synapse with the plasma membrane of the fiber, which alone shows the increased thickness often observed in both pre- and postsynaptic elements. Secondly, in addition to the synaptic vesicles within the axon are present, in the immediately adjacent sarcoplasm, great numbers of larger postsynaptic vesicles which, it is tentatively suggested, may represent the sites of storage of the enzymatic destroyer of the activating substance similarly quantized within the intra-axonal vesicles. The spatial relationship between the peripherally located junctions and the portion of the fiber plasma membrane internalized as circumtracheolar sheaths is considered, and the possible significance of this with respect to impulse conduction is discussed briefly.     

缘脊叶蝉亚科生物地理学研究(同翅目,叶蝉科)

对缘脊叶蝉亚科的组成,族、属和种的地理分布,以及起源与扩散途径进行了研究.结果表明:缘脊叶蝉亚科由7族57属323种组成,只分布于旧世界(Old World).7个族在非洲区均有分布,古北区有4个族、东洋区3个族、澳洲区2个族.依种类分布情况对4大动物区的相似性分析表明,东洋区与古北区关系最为密切,其次是澳洲区,与非洲区的相关性较小,这与地球演化历史是相吻合的.通过对各族地理分布及起源时间分析,它们的起源时间依次是:Drabescini、Paraboloponini、Selenocephalini、Ianeirini、Adamini、Dwightiini和Hypacostemmini.文中给出了各族的地理分布图.     

THE ELECTRON MICROSCOPIC LOCALIZATION OF CHOLINESTERASE ACTIVITY IN THE CENTRAL NERVOUS SYSTEM OF AN INSECT, PERIPLANET A AMERICANAL.

The distribution of esterase activity in the last abdominal ganglion, the connectives and the cereal nerves of the cockroach Periplaneta americana has been investigated cytochemically. Activity of an unspecific eserine-insensitive esterase (or esterases) has been found in glial elements in these regions of the nerve cord. In addition, sites of cholinesterase (eserine-sensitive) activity have been found in association with (a) the glial sheaths of the axons in the cereal nerves and connectives, (b) the glial folds encapsulating the neuron perikarya in the ganglion, and (c) in localized areas along the membranes of axon branches within the neuropile, often flanked by focal clusters of synaptic vesicles. These results are discussed with particular reference to the previously reported insensitivity of the insect nerve cord to applied acetylcholine, and to the probable existence of a cholinergic synaptic mechanism in the central nervous system of this insect.