Insecticidal activity of Bacillus laterosporus

Strains of Bacillus laterosporus demonstrated pathogenic activity for second-instar larvae of the mosquito, Culex quinquefasciatus, but failed to demonstrate detectable pathogenicity against larvae of the cabbage looper, Trichoplusia ni. Of 29 strains of the bacterium screened, 16 displayed pathogenicity for mosquito larvae. One of the most pathogenic strains, NRS 590, also demonstrated pathogenic activity for larvae of the mosquito, Aedes aegypti, and for larvae of the black fly, Simulium vittatum. The pathogenicity for Culex larvae was associated with the cell mass rather than with the culture supernatant. A suspension of ultraviolet irradiation-killed cells demonstrated no loss in pathogenic activity, an indication that the pathogenicity is toxin mediated. The toxic substance produced by NRS 590 was found to be resistant to heating at 96°C for 10 min. The toxin was not associated with the heat-resistant, bacterial endospore or with the associated paraspore since a suspension consisting primarily of spores was not toxic to mosquito larvae. Toxic activity in stationary phase cells of NRS 590 was associated with the cell's particulate fraction rather than with the soluble fraction.     

昆虫激肽的生理功能及机制

昆虫激肽是一类高度保守的小分子神经活性物质,自其从马德拉蟑螂脑中分离得到至今,人们在多种无脊椎动物体内均发现了这一激肽家族成员。它们具有促进昆虫后肠收缩、马氏管扭动、原尿分泌,调节血淋巴量和水盐平衡,使马氏管跨膜电位去极化,抑制昆虫体内消化酶释放、幼虫体重增长等功能。然而,天然的昆虫激肽很容易被蛋白酶所降解,因此须对其进行结构改造及构效关系研究,以开发出更有潜力的假肽和非肽模拟抗酶解昆虫激肽类似物,对今后实现环境友好型害虫防治策略具有重要意义。     

Novel visual-cue-based sticky traps for monitoring of emerald ash borers, Agrilus planipennis (Col., Buprestidae)

We examined various methods of trapping emerald ash borers (EAB), Agrilus planipennis Fairmaire, using solely visual cues based on previous work that has documented the importance of visual cues in EAB mate location. Here, we give the results of two of these methods, coloured sticky cards (yellow or blue), or live ash leaves covered with spray-on adhesive to which dead male EAB visual lures had been pinned. Feral male beetles were captured effectively on the sticky traps made from dead male EAB on ash leaves. These sticky-leaf-traps captured more male EAB when deployed in high-population density areas than low-density areas, but did capture EAB even at lower population densities. More feral males were captured on these traps when they were placed higher in the trees, regardless of the population density of EAB. Very few feral female EAB were captured using the sticky-leaf-traps. This novel method of EAB trapping may allow 'real-time' population detection and monitoring of EAB adults during the active flight period rather than locating larval galleries during the autumn and winter after adult flight and attack. Feral male beetles were also captured using standard yellow- or blue-coloured sticky cards to which male EAB had been affixed with adhesive; however, this type of trap was much less effective overall than using the sticky-leaf-traps. Furthermore, Agrilus cyanescens , a species similar in colour to EAB but smaller in size, showed a strong response to blue-coloured sticky traps to which dead male EAB had been affixed with adhesive, suggesting a general use of visual cues in the mating systems of some of the other Buprestidae as well.     

Impact of urbanization on a gall-inhabiting Lepidoptera assemblage: the importance of reserves in urban areas

This paper examines the structure of a Lepidoptera assemblage in an urban environment in South Africa. The Lepidoptera inhabit fungus-induced galls on Acacia karroo. Habitat patches supporting the moth assemblage were sampled from rural, urban-reserve, suburban and city sites and the habitat quality at each of these sites was quantified. Gall occupancy, larval density and species richness were lowest at the most disturbed, city sites. Non-parametric multivariate techniques showed that the moth-assemblage structure did not differ significantly at rural and urban-reserve sites. Assemblage structure at the suburban sites was variable and appeared to be transitional in structure between the city assemblage and the rural and urban-reserve assemblages. Habitat quality variables however were weakly correlated with moth-assemblage structure. The contribution of urban reserves to the local sustainability of this Lepidoptera assemblage emphasizes the importance of maintaining green areas in and around cities.     

Insect diversity over 36 years at a protected Sierra Nevada (California) site: towards an evaluation of the insect apocalypse hypothesis

1. Recent authors have suggested that declines of insect abundance or diversity, documented first for particular insect taxa of high interest (e.g., butterflies, bees), may apply to insect diversity more generally. This has led to an urgent call for analysis of additional longitudinal datasets to examine trends in general insect diversity.
2. Here we present a dataset gathered from 1982 to 2018 by advanced undergraduate students and graduate students enrolled in a taxonomy course that involved collecting as many insect families as possible over a 5-week period at a high-elevation protected forested site in the Sierra Nevada, California, USA.
3. The data do not support any consistent gain or loss of family-level richness between 1982 and 2018 (no linear trend); a non-linear model suggested a possible small decrease in family-level richness collected between 1986 and 1990, followed by a gradual increase from 1990 to 2018. Neither weather variables nor collector experience or skill appeared to explain among-year variation in collected insect diversity.
4. We urge caution in attempting to draw conclusions from single-site, longitudinal datasets like this one; a definitive answer to the hypothesis of a broad, global decline of insect diversity will require the joint analysis of many datasets like the one we share here.

     

昆虫标本馆建设与昆虫系统学的未来

昆虫标本馆是昆虫标本的保藏、研究和科学教育的实体,代表国家或者区域水平,致力于研究昆虫多样性、揭示昆虫进化规律,为国民经济建设持续发展服务。昆虫系统学研究是昆虫标本馆研究人员的主要任务,它的发展与昆虫标本馆的建设唇齿相依。本文阐述了昆虫标本馆的功能与作用,建设昆虫标本馆的重要性和迫切性;展望了昆虫系统学的未来以及昆虫系统学发展的机遇。     

A look into the invisible: ultraviolet-B sensitivity in an insect (Caliothrips phaseoli) revealed through a behavioural action spectrum

Caliothrips phaseoli, a phytophagous insect, detects and responds to solar ultraviolet-B radiation (UV-B; λ ≤ 315 nm) under field conditions. A highly specific mechanism must be present in the thrips visual system in order to detect this narrow band of solar radiation, which is at least 30 times less abundant than the UV-A (315–400 nm), to which many insects are sensitive. We constructed an action spectrum of thrips responses to light by studying their behavioural reactions to monochromatic irradiation under confinement conditions. Thrips were maximally sensitive to wavelengths between 290 and 330 nm; human-visible wavelengths (λ ≥ 400 nm) failed to elicit any response. All but six ommatidia of the thrips compound eye were highly fluorescent when exposed to UV-A of wavelengths longer than 330 nm. We hypothesized that the fluorescent compound acts as an internal filter, preventing radiation with λ > 330 nm from reaching the photoreceptor cells. Calculations based on the putative filter transmittance and a visual pigment template of λ_max = 360 nm produced a sensitivity spectrum that was strikingly similar to the action spectrum of UV-induced behavioural response. These results suggest that specific UV-B vision in thrips is achieved by a standard UV-A photoreceptor and a sharp cut-off internal filter that blocks longer UV wavelengths in the majority of the ommatidia.     

Vitamin C content in plants is modified by insects and influences susceptibility to herbivory

Analysis of a diverse cross‐sample of plant‐insect interactions suggests that the abundance of vitamin C (L ‐ascorbic acid, ascorbate or AsA) in plants influences their susceptibility to insect feeding. These effects may be mediated by AsAs roles as an essential dietary nutrient, as an antioxidant in the insect midgut, or as a substrate for plant‐derived ascorbate oxidase, which can lead to generation of toxic reactive oxygen species. Ascorbate can also influence the efficacy of plant defenses such as myrosinases and tannins, and alter insects' susceptibility to natural enemies. Conversely, herbivores appear to influence both de novo synthesis and redox cycling of AsA in their host plants, thereby potentially altering the nutritional value of crops and their susceptibility to pests. The recent development of genetically modified crops with enhanced AsA content provides both an impetus and a tool set for further studies on the role of AsA in plant‐insect interactions.     

Insect cells as hosts for the expression of recombinant glycoproteins

Baculovirus-mediated expression in insect cells has become well-established for the production of recombinant glycoproteins. Its frequent use arises from the relative ease and speed with which a heterologous protein can be expressed on the laboratory scale and the high chance of obtaining a biologically active protein. In addition to Spodoptera frugiperda Sf9 cells, which are probably the most widely used insect cell line, other mainly lepidopteran cell lines are exploited for protein expression. Recombinant baculovirus is the usual vector for the expression of foreign genes but stable transfection of - especially dipteran - insect cells presents an interesting alternative. Insect cells can be grown on serum free media which is an advantage in terms of costs as well as of biosafety. For large scale culture, conditions have been developed which meet the special requirements of insect cells.With regard to protein folding and post-translational processing, insect cells are second only to mammalian cell lines. Evidence is presented that many processing events known in mammalian systems do also occur in insects. In this review, emphasis is laid, however, on protein glycosylation, particularly N-glycosylation, which in insects differs in many respects from that in mammals. For instance, truncated oligosaccharides containing just three or even only two mannose residues and sometimes fucose have been found on expressed proteins.These small structures can be explained by post-synthetic trimming reactions. Indeed, cell lines having a low level of N-acetyl--glucosaminidase, e.g. Estigmene acrea cells, produce N-glycans with non-reducing terminal N-acetylglucosamine residues. The Trichoplusia ni cell line TN-5B1-4 was even found to produce small amounts of galactose terminated N-glycans. However, there appears to be no significant sialylation of N-glycans in insect cells. Insect cells expressed glycoproteins may, though, be 1,3-fucosylated on the reducing-terminal GlcNAc residue. This type of fucosylation renders the N-glycans on one hand resistant to hydrolysis with PNGase F and on the other immunogenic. Even in the absence of 1,3-fucosylation, the truncated N-glycans of glycoproteins produced in insect cells constitute a barrier to their use as therapeutics. Attempts and strategies to mammalianise the N-glycosylation capacity of insect cells are discussed.     

Establishment and characterization of a cell line from embryos of the Indianmeal moth,Plodia interpunctella

A cell line, UMN-PIE-1181, initiated in November, 1981, from embryos of a malathion-resistant strain of Indianmeal moth, Plodia interpunctella, was in the 83rd passage on January 28, 1985. The line consists of single, small, fibroblastlike cells that are polyploid with chromosome numbers ranging from 56 to 180. Growth rate is dependent on seeding density, there being no growth at or below seeding densities of $\text{2 ×}\text{10}{}^5\text{5}\text{,}\text{ml}$; optimum growth requires a fetal bovine serum concentration of at least 5%. Twenty-nine isozymes were examined. Five enzymes from the cell lines resolved well and subsequently were compared to enzymes extracted from 4-day-old embryos and other life stages of the insects. Phosphomannose isomerase, malic enzyme, malate dehydrogenase, phosphoglucose isomerase, and glucose-6-phosphate dehydrogenase in extracts from the cultured cells and from the insects had identical patterns. Two bands for glutamate-oxalacetate transaminase, present in the cell line, were not observed in the tissue extracts. Furthermore, lactate dehydrogenase from the cultured cells appeared as four bands but was not detectable in any of the samples run from the various life stages of the insects.     

RNAi技术在昆虫学中的研究进展及展望

在昆虫中,RNAi是一种对抗外源病毒的天然免疫方式,基于生物体中的这种内在机制而建立的RNAi技术已经被广泛用来研究多种昆虫基因的功能。近年的研究结果表明RNAi技术在抵御害虫和防治益虫疾病方面具有潜在的应用价值,有可能对农业有害生物的控制起到巨大的推动作用。本文综述了RNAi与昆虫免疫、及其在昆虫基因功能研究、害虫控制、益虫疾病控制和昆虫系统生物学方面的最新研究进展,并展望了RNAi在昆虫学研究中的发展趋势。     

Effects of elevated temperature and carbon dioxide on the nutritional quality of leaves of oak (Quercus robur L.) as food for the Winter Moth (Operophtera brumata L.)

1. Pedunculate Oak trees were grown in ambient and elevated temperatures and CO₂. Leaves were fed to Winter Moth caterpillars reared either in constant conditions or with the trees (caged or on-tree).
2. Caterpillars in constant conditions ate the same mass and produced the same mass of faeces whether fed elevated or ambient temperature leaves. However, less was assimilated from elevated leaves, resulting in lighter pupae and fewer, lighter eggs.
3. Caterpillars in constant conditions ate more and produced more faeces when fed elevated CO₂ leaves than when fed ambient CO₂ leaves, but the mass assimilated and pupal mass were unchanged.
4. Caged caterpillars reared with the trees from which they were fed had constant pupal mass in all treatments, but pupated earlier at elevated temperature. Pupal mass was also unaffected when caterpillars fed on the trees.
5. Nitrogen was reduced in both elevated temperature and elevated CO₂ leaves. Increased fibre in the former prevented increased consumption and resulted in reduced pupal mass and fecundity. Reduced fibre in the latter allowed increased consumption, resulting in pupae of normal mass.
6. Despite the clear effect of nutrient quality, experiments rearing caterpillars and trees together suggest that anticipated climatic change will have no nutritional effect on Winter Moth development.     

贵州九香虫营养成分分析

分析贵州产九香虫Aspongopus chinensis Dallas体内的营养成分。结果表明:从江和习水产九香虫都具有丰富的营养,其中粗蛋白分别为350.9mg·g-1和356.5mg·g-1、粗脂肪432.6mg·g-1和436.2mg·g-1、粗灰分22.9mg·g-1和22.8mg·g-1;总氨基酸含量为334.3mg·g-1和253mg·g-1,其中必需氨基酸占总氨基酸的41.22%和33.34%,必需氨基酸与非必需氨基酸之比分别为0.70和0.50;九香虫体内脂肪酸多以油酸和软脂酸为主,其中油酸占总脂肪酸的49.48%和41.54%;含有丰富的矿物质和微量元素,尤其是Mg的含量达到1.26mg·g-1和1.32mg·g-1,且不含有对人体有害的Hg、Pb和As;含有多种维生素,其中维生素C含量最为丰富,为0.78mg·g-1和0.79mg·g-1。作为具有保健功能的中药昆虫,同时具有丰富的营养成分,九香虫是极具潜力的药食两用食品。     

洋虫营养成分分析

分析洋虫Palembus dermestoides(Fairmaire)成、幼虫体内的营养成分,并对氨基酸的质量进行了评价。结果表明:洋虫成虫和幼虫都具有丰富的营养,其中粗蛋白48.31%和54.94%、粗脂肪17.64%和18.24%、粗灰分3.0%和2.8%、总糖31.05%和24.08%,TAA为39.03 g/100 g和47.4 g/100 g、EAA/TAA为46.29%和47.14%,含有丰富的矿物质和微量元素,尤其是Zn的含量达到101.00 mg/kg和186.00 mg/kg,且不含有对人体有害的Cd,Hg,Pb。对幼虫进行氨基酸评价,其必需氨基酸指数为114.71。与目前常见的蛋白源相比较,洋虫是一种高蛋白、低脂肪、氨基酸含量较全面且富含矿物质和微量元素的昆虫资源。     

Some effects of CGA 72662 on larval development in the housefly,Musca domestica (L.)

Summary

Houseflies reared on artificial diet supplemented with a range of concentrations of CGA 72662 suffered severe developmental disruption at the larval stage. Death was preceded by the appearance of a range of cuticular lesions and abnormalities. These cuticular abnormalities have been observed under the light and electron microscopes.     

Effects of ribosome inactivating proteins on insect development —differences between Lepidoptera and Coleoptera

Ricin and saporin represent two different classes of ribosome inactivating proteins (RIPs), or cytotoxins, present in plant seeds. The toxicity of these substances to several eukaryotic organisms is widely known, as is their intracellular mode of inhibitory action on the ribosomes. However virtually nothing is known of the effects of these substances on insects. In this paper we report on systematic studies which indicate that RIPs can be extremely toxic to insects although the effects are variable with different insect orders. Specifically, two Coleopteran species were extremely susceptible to the effects of both RIP's with average LD₅₀ values of less than 10^-2% (dry weight). The studies also indicate that resistance to the toxic effects, exhibited by Lepidopteran insects, may be due in part to the protease complements of the insect guts which are capable of hydrolysing the RIPs, thus eliminating them before they are absorbed and can exert their effects within the insects cells.

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Résumé La ricine et la saporine des graines de plantes représentent deux classes différentes de protéines inactivant les ribosomes (RIPs), ou cytotoxines. La toxicité de ces substances pour plusieurs eucaryotes est bien connue, de même que le processus intracellulaire de leur activité inhibitrice des ribosomes. Cependant, on ne connaît pratiquement rien de leurs effets sur les insectes. Dans cet article, nour relatons des travaux systématiques qui montrent que les RIPs peuvent être extrêmement toxiques pour les insectes, bien que leurs effects varient suivant les ordres d'insectes.Particulièrement, deux espèces de coléoptères sont extrêmement sensibles aux effets des deux RIPs avec des DL₅₀ inférieures à `0^-2% du poids sec. Ces travaux indiquent aussi que la résistance des lépidoptères à ces effets toxiques peut être due en partie à la présence dans leur intestin de protéases susceptibles d'hydrolyser les RIPs, et de les éliminer ainsi avant leur absorption et avant qu'elles ne puissent exercer leurs effets dans les cellules des insectes.

     

Feeding behavior: selection of both wet and dry food for increased growth in Schistocerca gregaria nymphs

An apparent fluctuating preference in acridids for food of different water contents is confirmed for Schistocerca gregaria nymphs. Short- and long-term preference tests reveal that previous diet, through its effect on locust water balance and overall food intake, can influence feeding behavior on high-water content (wet) and low-water content (dry) food. Locusts given only wet or dry food for 3 days prior to testing initially chose the food not received in pretreatment when given a choice of the two. They had decreased latencies to feed, increased meal length and decreased switching between food types as compared with locusts given the option to regulate water intake before testing. It is suggested that the behavior of the single-diet locusts has several related causes, among them, deterrence of the food, disturbed water balance in the locust, and chronic hunger. Long-term preference tests reveal that fifth-instar locusts given a continuous choice between wet and dry food take significantly more of their total dry matter from dry food each day until the last feeding day of the instar (day 9), when they take 97% of their total dry matter from wet food. This behavioral regulation of water and dry matter intake is adaptive: locusts with access to a mixed diet of wet and dry food have increased growth as compared with ones given only wet food. The growth increase is due largely to increased dry matter consumption, with some contribution from increased digestive efficiency and reduction in respiratory rate.

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Résumé L'étude de larves de dernier stade de Schistocerca gregaria confirme les observations sur les acridiens d'une préférence apparemment labile pour les aliments à différentes teneurs en eau. Des observations sur les choix à court et à long termes rélèvent que le régime alimentaire antérieur, par son action sur le régime hydrique du criquet et sur sa prise totale de nourriture, peut influer sur le comportement alimentaire face à des aliments à forte teneur en eau (humides ou frais) ou à faible teneur (secs). Des criquets, approvisionnés uniquement en aliments secs ou frais pendant les 3 jours précédant l'expérience, choisissent de préférence la catégorie d'aliments non fournie pendant ce prétraitement. Par comparaison avec des criquets ayant eu la possibilité d'ajuster leur apport en eau avant l'expérience, ils présentaient une diminution du temps de latence avant de s'alimenter, une prolongation de la durée des repas et une diminution du nombre de changements de type d'aliments. II est suggéré que le comportement des criquets, à régime alimentaire composé d'un seul type, a plusieurs causes associées, en particulier la répulsion pour le végétal, la perturbation de l'état hydrique du criquet, et la faim chronique. Des tests sur les préférences à long terme montrent que des larves de 5ème stade ayant eu un choix continu entre aliments frais et secs prirent significativement plus de leur matière totale d'aliments secs jusqu'à ce qu'elles parviennent au dernier jour d'alimentation du stade (jour 9), alors elle prélevèrent 97% de leur matière sèche totale d'aliments frais. Cette régulation comportementale de l'absorption d'eau et de matière sèche est adaptative: des criquets ayant accès à une alimentation mixte (nourriture sèche et fraîche) ont unt croissance supérieure à ceux nourris exclusivement d'aliments frais. La croissance supérieure est due pour beaucoup à une consommation accrue de matière sèche, avec une légère contribution de l'amélioration de l'efficacité digestive et de la réduction du taux de respiration.

     

Plant characteristics determine insect borer assemblages on Protea species in the Cape Fynbos, and importance for conservation management

The influence of regional climate, biotope and host-plant variables on the frequency of occurrence of insect borers associated with infructescences of Protea species in the species-rich flora of the Cape Fynbos was investigated. Large samples of infructescences (n=1000) were collected on a seasonal basis and borers identified and quantified. Data were analysed using DECORANA and CANOCO so as to correlate environmental variables with borer occurrence. Distinct differences in frequency of occurrence of the various insect taxa were recorded on the various plant species studied. These differences were primarily accounted for by physical host-plant characteristics (infructescence and seed set variables), and secondarily, by biotope variables and climatic factors. Fynbos plant characteristics therefore play a major role in determining insect abundance. Plant diversity in the Fynbos is maintained by burning. These management burns, however, should not be applied too frequently or over areas large enough to extirpate any borer species. As these borers are excellent umbrellas for many other insects, their conservation covers Fynbos insect diversity in general.     

虫瘿—昆虫与植物互作的奇特产物

虫瘿是昆虫刺激产生的植物不正常组织。造瘿昆虫几乎能在高等植物的所有类群中产生形态各异的虫瘿,甚至能在同一种植物上形成多种形态不一的虫瘿。虫瘿形成的机制仍不清楚,普遍认为是昆虫控制了虫瘿的形成,但植物细胞也参与了虫瘿形成的调控。为了探索这一神秘的领域,科学家们已经对昆虫的刺激物以及植物的反应作了大量的研究,未来工作的难点将是如何把二者联系起来。     

昆虫生长调节剂的毒理机制与抗药性研究进展

昆虫生长调节剂是通过干扰昆虫正常生长发育,致使昆虫个体死亡或活动能力下降,从而导致种群灭绝的一类特异性杀虫剂。本文对3类重要的昆虫生长调节剂（保幼激素类似物、几丁质合成抑制剂和蜕皮激素类似物）的毒理作用机制以及害虫对其抗药性的研究进展进行了综述,叙述了害虫对该类药剂的抗药性发展情况,并对其抗药性机理进行了探讨。目前研究表明,害虫对该类药剂的主要抗性机理是解毒代谢酶增强和表皮穿透率降低。