Ultrastructure of pheromone-producing eversible vesicles in males of Chrysopa perla L. (Insecta,Neuroptera)

Summary During courtship, males of Chrysopa perla extrude from the genital aperture two eversible vesicles that bear approximately 50 sclerotized tubercles with a long, apical hair. Ultrastructural study reveals within each tubercle two juxtaposed subunits: a sensory subunit formed by a mechanoreceptor neuron, a glial cell, two enveloping cells, and a glandular subunit consisting of a glandular cell provided with an extracellular reservoir, a duct cell and an enveloping cell. The glandular-cell cytoplasm is characterized by extensive RER, a large amount of SER, probably involved in lipid elaboration, and voluminous myeloid bodies encircling the reservoir. The secretion is released to the outside by a cuticular duct that opens into the side of the tubercle. The function of the mechanoreceptor associated with the glandular subunit is discussed.     

Ultrastructure of trophocyte nuclei in polytrophic ovarioles of Chrysopa perla (Neuroptera)]

The light and electron microscope and autoradiographic studies (H3-uridin incorporation) were carried out on the trophocyte nuclei of imago polytrophic ovarioles of Chrysopa perla (Neuroptera), from the trophocyte differentiation up to their degeneration. Like the oocytes, one of the seven nurse cells o every ovariole chamber contains extrachromosomal DNA bodies. This nurse cell is formed during differential mitoses in the germarium as one of two prooocytes. In contrast to extrachromosomal DNA of oocytes the trophocyte DNA bodies are less active structures. Several (2--4) complex nucleoli develop in the trophocytes of Chrysopa in the early stages of oogenesis. They consist of three main components: the chromatin mass, fibrillar bodies and granular strands. Such nucleoli grow, through increasing in number of fibrillar bodies and granular strands. They are most developed by the start of the vitellogenesis. At the middle vitellogenesis the general nucleolar structure modify due to the beginning of trophocyte degeneration. The consecutive stages of nuclear degeneration are described. The trophocyte nucleoli synthesize RNA still in germarium. The most intensive RNA synthesis is observed at the beginning of the vitellogenesis to decrease by the beginning of trophocyte degeneration.     

Isopropanol attracts the green lacewing,Chrysopa quadripunctata (Neuroptera: Chrysopidae)

Adult female green lacewings, Chrysopa quadripunctata Burmeister, were attracted to traps baited with 45% isopropanol in an unsprayed apple orchard in Missouri, USA. No lacewings were attracted to the unbaited traps. To the best of our knowledge this is the first report on a semiochemical that attracts lacewings of this species.     

Unconventional ultraviolet sensitivity spectra of Ascalaphus (Insecta,Neuroptera)

The spectral sensitivity of 21 eye preparations of Ascalaphus (Libelluloides) macaronius (Insecta, Neuroptera) has been re-measured using an up-to-date spectral scan method. 1. Dorso-frontal and ventro-lateral eyes have different spectral characteristics with peaks of sensitivity at 329 ± 8 nm (n = 15) and 343 ± 4 nm (n = 5) (P = 0.002), respectively. 2. The absorbance of the visual pigment layer, K, determined from the shape of the spectral sensitivity curves is 1.3 ± 1.8(n = 15) for dorso-frontal eyes and – 1.0 ± 0.3(n = 5) for ventrolateral eyes, thus implying higher selfscreening in the dorso-frontal eyes and narrowing of the spectral sensitivity curves as regards to a template visual pigment in ventro-lateral eyes. 3. Plotting K versus spectral sensitivity peak wavelength _max revealed an inverse correlation between these variables with K = 42.5 – 0.126 _max at r = 0.88(n = 19). 4. Extracts of ommochromes and carotenoids (Figs. 4 to 6) do not allow to account for the above diversity of optical properties of the Ascalaphus eye (Fig. 7).Abbreviations SSC spectral sensitivity curve - DF dorso-frontal eye - UV ultraviolet - VL ventro-lateral eye     

Sperm ultrastructure and spermiogenesis of Coniopterygidae (Neuroptera, Insecta)

The spermiogenesis and the sperm ultrastructure of several species of Coniopterygidae have been examined. The spermatozoa consist of a three-layered acrosome, an elongated elliptical nucleus, a long flagellum provided with a 9+9+3 axoneme and two mitochondrial derivatives. No accessory bodies were observed. The axoneme exhibits accessory microtubules provided with 13, rather than 16, protofilaments in their tubular wall; the intertubular material is reduced and distributed differently from that observed in other Neuropterida. Sperm axoneme organization supports the isolated position of the family previously proposed on the basis of morphological data.     

“中生代的蝴蝶”——脉翅目丽蛉类昆虫

丽蛉类昆虫是脉翅目昆虫在中生代特有的一类绝灭昆虫,被誉为"中生代的蝴蝶",其体型巨大、脉序复杂,部分身体特征高度特化,与现代脉翅目昆虫表现出明显的差异,而其在脉翅目演化中的地位也是一直难以确定。同时,由于化石保存的局限性,该类昆虫多是依靠不完整的结构进行分类,缺少系统的总结和修订,也为该类群的深入研究带来了很大的困难。本文对中生代丽蛉类昆虫进行了总结,统计了至今全世界所发现的所有丽蛉类昆虫名录,概述了其研究历史,地质年代及地理分布,系统发育研究进展,功能形态学研究及生态学特性等问题,并提出了研究该类群有待解决的问题及研究展望。     

Action of photoperiod at cold in diapausing Chrysopa carnea females (Chrysopidae,Neuroptera)

Summary To reveal the effect of photoperiod on insects under low temperatures, dormant females of Chrysopa carnea were exposed for 3 months (November–January) to cold (7°±2.5°C) and to long- or short-day conditions (18L:6D or 12L:12D). They were thereafter activated under short-day conditions at 25°C.The samples differed considerably in the incidence of ovipositing females, duration of pre- and post-oviposition period, and fecundity. All parameters evidenced a considerably higher reproductive activity of insects chilled under short-day conditions. It was thus confirmed that adults of C. carnea perceive photoperiod at cold. The action of short photoperiod at cold does not impair the subsequent oviposition; by contrast it promotes future reproduction, apparently also due to photoperiod changes. Although short-day photoperiod inhibits the activation at warm temperatures, it enables diapause development under cold temperatures.Dedicated to Prof. Dr. Hans Joachim Müller, Jena, on the occasion of his 65th birthday     

Chromosome numbers in antlions (Myrmeleontidae) and owlflies (Ascalaphidae) (Insecta,Neuroptera)

A short review of main cytogenetic features of insects belonging to the sister neuropteran families Myrmeleontidae (antlions) and Ascalaphidae (owlflies) is presented, with a particular focus on their chromosome numbers and sex chromosome systems. Diploid male chromosome numbers are listed for 37 species, 21 genera from 9 subfamilies of the antlions as well as for seven species and five genera of the owlfly subfamily Ascalaphinae. The list includes data on five species whose karyotypes were studied in the present work. It is shown here that antlions and owlflies share a simple sex chromosome system XY/XX; a similar range of chromosome numbers, 2n = 14-26 and 2n = 18-22 respectively; and a peculiar distant pairing of sex chromosomes in male meiosis. Usually the karyotype is particularly stable within a genus but there are some exceptions in both families (in the genera Palpares and Libelloides respectively). The Myrmeleontidae and Ascalaphidae differ in their modal chromosome numbers. Most antlions exhibit 2n = 14 and 16, and Palparinae are the only subfamily characterized by higher numbers, 2n = 22, 24, and 26. The higher numbers, 2n = 20 and 22, are also found in owlflies. Since the Palparinae represent a basal phylogenetic lineage of the Myrmeleontidae, it is hypothesized that higher chromosome numbers are ancestral for antlions and were inherited from the common ancestor of Myrmeleontidae + Ascalaphidae. They were preserved in the Palparinae (Myrmeleontidae), but changed via chromosomal fusions toward lower numbers in other subfamilies.     

Jurassic lacewings (Insecta: Neuroptera) of Western Siberia

A lacewing assemblage from the Middle Jurassic of the West Siberian Kubekovo locality, the only know Jurassic lacewing fauna of Russia, is discussed. One new genus and two new species of Osmylidae from Kubekovo, Kubekius multiramosus gen. et sp. nov. and Epiosmylus longus sp. nov. are described. Thaumatomerobius mirabilis Ponomarenko, 1985 is transferred to the family Saucrosmylidae, which has only been recorded in the Middle Jurassic of Daohugou.     

Ultrastructural studies on euspermatozoa and paraspermatozoa in Mantispidae (Insecta, Neuroptera)

Previous studies have demonstrated the presence of sperm dimorphism in the Mantispidae Perlamantispa perla. We extended the study on several other mantidflies. In all the examined species the occurrence of euspermatozoa (typical) and paraspermatozoa (atypical) was established. The euspermatozoa are characterized by the presence of a cylindrical nucleus surrounded by an envelope that fans out laterally into two thin wings of different length. The acrosome seems to be missing. The nucleus is surrounded by extracellular material. The flagellum is provided with a 9 + 9 + 2 axonemal pattern; the accessory tubules contain 16 protofilaments and the intertubular material has the distribution typical of the taxon. Two elongated accessory bodies flank partially the axoneme and connect this structure with the mitochondrial derivatives. The flagellar axoneme of paraspermatozoa consists of an axoneme and two giant mitochondrial derivatives filled with large globular units. The axoneme exhibits a 9 + 9 + 2 pattern, in which the central 9 + 2 units have a normal structure, in that the microtubular doublets are provided with both dynein arms and radial links. On the contrary, the nine accessory microtubules have a large diameter and their tubular wall consists of 40 protofilaments. This comparative study provided evidences about the uniformity of sperm ultrastructure in Mantispidae. The function of non-fertilizing giant sperm in mantidflies is discussed.     

Rearing of Chrysopa pallens (Rambur) (Neuroptera: Chrysopidae) on Artificial Diet

An artificial rearing method was designed for the generalist predator, Chrysopa pallens (Rambur). The rearing media were formulated based on, Orius strigicollis diets for feeding larvae, and two diets for adults were prepared with insect source and non‐insect as their main components. Development of the predators was successfully obtained with the diets for both larval and adult stages. The impact of these diets was recorded for growth during the larval stage and oviposition rates by the females. Total development period and mortality rate of, C. pallens were about 26.9 days and 11%, respectively. The females showed better reproduction with average of 2019 eggs over their life span of 89 days when the artificial diet with non‐insect source was provided. On overall basis the life expectancy and fecundity was better when compared with previous findings.     

Seasonal development of the lacewing Chrysopa dorsalis Burmeister (Neuroptera, Chrysopidae) in the forest-steppe zone of Russia

Seasonal adaptations of Chrysopa dorsalis Burmeister were studied in Belgorod Province of Russia (50°N, 36°E). It was found that in the forest-steppe zone two generations may be produced, but from 76 to 100% of the prepupae of the first generation entered diapause, about 40% of them having an obligate diapause. In the rest of the population, seasonal development was controlled by photoperiod and temperature. The critical day length was about 17 h at 20°C. Some prepupae were found to require two or three years to complete the diapause. This prolonged diapause seems to be a permanent element of the life cycle of the studied species. The proportion of the prepupae that remain in diapause after the first winter positively correlated with the percentage of diapausing prepupae of the first generation in the previous season (r = 0.8). The offspring from eggs laid by females simultaneously collected under the natural conditions emerged in successive years, and the tendency to enter a long-term diapause was not inherited. The rate of the larvae development and the prepupae weight were not different in individuals which had one-year-long and prolonged diapause. However, the weight loss due to dehydration and respiration during the first winter was slightly lower in the prepupae with the prolonged diapause. The expression of the prolonged diapause was independent of the photoperiod during the diapause induction, but it was increased at a high temperature (28°C). Probably, the prolonged diapause increases polymorphism of local Ch. dorsalis populations, ensuring their survival under unpredictable conditions.     

Functional morphology of the midgut of Aedes aegypti L. (Insecta,Diptera) during blood digestion

Morphometric analysis of the epithelial lining of the stomach of A. aegypti suggests that digestion of the first blood meal in the stomach of this species can be viewed as a series of phases that can be correlated with physiological data from the literature. In phase Ia (0-10 h after blood meal [abm]) the whorls of the rough endoplasmic reticulum unfold, the Golgi zones increase, and the basal labyrinth is enlarged. This coincides with processes of synthesis and secretion (e.g., peritrophic membrane, esterases and lipases) and transport by the stomach epithelium. In phase Ib (10-20 habm) the cellular parameters measured further increase, indicating high synthetic and secretory activities (e.g., digestive enzymes). In phase Ic (20-30 habm) cell structures involved in synthesis and secretion still exhibit high values coinciding with maximal activity of proteases in the gut. Enhanced surface area of microvilli, prominent lipid inclusions, and appearance of glycogen deposits in the gut epithelium suggest increased absorption, storage, and transport functions of the stomach cells. In phase II (30-36 habm) structural alteration points to a gradual shift from synthesis and secretion to absorption, partial storage, and transport of nutrients. In phase III (36-72 habm) the cellular apparatus is reduced concomitant with the ending of the digestive cycle. Lipid inclusions and glycogen deposits disappear from the stomach epithelium.     

Neotropical Osmylidae larvae (Insecta,Neuroptera): description of habitats and morphology

ABSTRACT

The larval stages of the genus Kempynus Navás, 1912 Navás, L. (1912), ‘Insectos neurópteros nuevos o poco conocidos’, Memorias de la Real Academia de Ciencias y Artes de Barcelona, 10, 135–202. [Google Scholar] (probably K. falcatus Navás, 1912 Navás, L. (1912), ‘Insectos neurópteros nuevos o poco conocidos’, Memorias de la Real Academia de Ciencias y Artes de Barcelona, 10, 135–202. [Google Scholar] based on the presence of synchronic and sympatric adults) are described for the Neotropical Region for the first time, and the larval stages of Isostenosmylus pulverulentus (Gerstaecker, 1893 Gerstaecker, C.E.A. (1893), ‘Ueber neue und weniger gekannte Neuropteren aus der familie Megaloptera Burm’, Mitt[h]eilungen aus dem Naturwissenschaftlichen Verein für Neu-Vorpommern und Rugen, 25, 93–173. [Google Scholar]) are redescribed. The external morphology of third-instar larvae of both species and their habitats are described and compared. Kempynus sp. is a water-dependent species and can be considered semi-aquatic, whereas I. pulverulentus larvae are terrestrial and live in undergrowth vegetation. The first key to identification of Neotropical Osmylidae larvae is provided, based on third-instar larvae of both species.     

Geographical variability in ecophysiological traits controlling dormancy in Chrysopa oculata (Neuroptera: Chrysopidae)

Dormancy in Chrysopa oculata, a multivoltine species, is controlled by reponses to photoperiod and temperature. Variation in both the critical photoperiod for diapause induction and the duration of diapause is positively related to the latitudianl origin of the population. The incidence of photoperiodically induced diapause also varies geographically; at 24°C the southern-most population is more variable for diapause induction than the northern populations. By contrast, there is little interpopulation variation in thermally determined rates of post-diapause development. The results suggest that the lower threshold for development and the thermal requirements above the threshold may be functionally correlated.