Elaboration and testing of insecticidal varnish in aerosol containers for the control of synanthropic cockroaches

A formula for the filling of aerosol containers has been elaborated on the basis of a mixture of hexachlorocyclohexane (HCH) gamma isomer and tetrametrin, in a ratio 3:1 with the addition of furniture varnish NC-62 to produce the film, Khladon 11/12 (5050) served as propellent. The study of the process of crystallization of the insecticides on the surface of the film has shown that the effectiveness of insecticidal varnishes is the higher, the smaller the size of the crystals and the easier they can be removed from the surface of the film. This can be achieved by including tetrametrin along with HCH gamma isomer in the formula. The testing of the insecticidal activity and toxicity of aerosols prepared according to the elaborated formula has demonstrated high insecticidal activity of the composition with respect to synanthropic cockroaches and fairly low toxicity with respect to warm-blooded animals.     

Effects of electromagnetic fields on biological systems

The effect of power-frequency electric fields on invertebrate movement and behavior was studied. Data was obtained in the vicinity of an operating 500-kV powerline, and from underneath a simulated powerline (where the electric field could be controlled). Electric fields greater than 8-10 kV/m affected the behavior of flying insects; small insects could not fly, and large insects avoided the high-field region. Electric fields lowered both the activity of mosquitoes (to attack the host) and insect flower attendance. The prevalence of most non-flying insect species was not altered by the electric field, probably because of screening of the electric fields by vegetation and the ability of the insects to migrate. The existing Soviet safety standards for high-voltage powerlines seem sufficient to protect invertebrates.     

A DIPPING APPARATUS FOR ESTIMATING THE TOXICITY OF INSECTICIDES IN LIQUID MEDIA

An apparatus and a technique are described for the study of the effect of liquid insecticidal preparations by dipping insects in the toxic material. The method is applicable to quick-settling suspensions and quick-creaming emulsions as well as to solutions. Dipping is performed at constant temperature with end-over-end shaking; and the technique has the advantage over the other dipping methods that have been described in that handling of individual insects whilst wet is eliminated.     

Lehr's fields of campaniform sensilla in beetles (Coleoptera): Functional morphology. II. Wing reduction and the sensory field

Loss of the flight ability and wing reduction has been reported for many taxa of Coleoptera. If elytra are closed, their roots are clenched between the tergum and the pleuron, forces applied to the elytra can not be transmitted to the field of campaniform sensilla situated on the root. That is why it is plausible to assume that the field becomes redundant in non-flying beetles. We examined the relationships between the hind wing reduction and characters of this mechanosensory field in beetles of six families. We measured the size of the elytron, that of the hind wing and counted the number of sensilla in the sensory field. Mesopterous non-flying beetles retain one half to one third of sensilla present in macropterous species of the same body size. Further reduction of the sensory field in brachypterous species is obvious, but sensilla are still present in insects with strongly reduced wings, as long as their elytra are separable and mesothoracic axillaries are present. Complete loss of sensilla coincides with the existence of a permanent sutural lock. However, some beetles with permanently locked elytra and absence of axillaries still retain few campaniform sensilla. A very special case of an extreme wing modification in feather-wing beetles is considered. No sensilla were revealed either on the root of the elytron or on the basal segment of such fringed wings in flying ptiliid species.     

Influence of carbon sources on the biological activity and morphology of Bacillus thuringiensis parasporal crystals]

The influence of the carbon source on biological activity and morphological properties of the parasporal crystals of Bacillus thuringiensis subsp. kurstaki cultivated on three different media has been studied. Biological activity of delta-endotoxins contained in crystals was tested according to their impact on insects and microorganisms. Variations in carbon sources composition resulted in changes of biological activity and morphology of crystals, caused by alterations in synthesis rate of various delta-endotoxins contained in the crystals. Variations in the content of a certain carbon source (e.g. starch) in the medium produced no effect on the crystals properties, and the content variations of the delta-endotoxins content was proportional to the producer biomass. Control of the antibacterial effect of delta-endotoxins allows a valid evaluation of their biological activity under various growth conditions as well as comparison of the biological potential of entomopathogenic chemicals for plant protection containing delta-endotoxins with different specificity of insecticidal activity.     

Determinants of abundance and effects of blood-sucking flying insects in the nest of a hole-nesting bird

Compared to non-flying nest-dwelling ectoparasites, the biology of most species of flying ectoparasites and its potential impact on avian hosts is poorly known and rarely, if ever, reported. In this study we explore for the first time the factors that may affect biting midge (Diptera: Ceratopogonidae) and black fly (Diptera: Simuliidae) abundances in the nest cavity of a bird, the hole-nesting blue tit Cyanistes caeruleus, and report their effects on adults and nestlings during reproduction. The abundance of biting midges was positively associated with nest mass, parental provisioning effort and abundance of blowflies and black flies, while negatively associated with nestling condition. Furthermore, a medication treatment to reduce blood parasitaemias in adult birds revealed that biting midges were more abundant in nests of females whose blood parasitaemias were experimentally reduced. This finding would be in accordance with these insect vectors attacking preferentially uninfected or less infected hosts to increase their own survival. The abundance of black flies in the population was lower than that of biting midges and increased in nests with later hatching dates. No significant effect of black fly abundance on adult or nestling condition was detected. Blood-sucking flying insects may impose specific, particular selection pressures on their hosts and more research is needed to better understand these host–parasite associations.     

Environmental filtering and spatial effects on metacommunity organisation differ among littoral macroinvertebrate groups deconstructed by biological traits

We examined spatial and environmental effects on the deconstructed assemblages of littoral macroinvertebrates within a large lake. We deconstructed assemblages by three biological trait groups: body size, dispersal mode and oviposition behaviour. We expected that spatial effects on assemblage structuring decrease and environmental effects increase with increasing body size. We also expected stronger environmental filtering and weaker spatial effect on the assemblages of flying species compared with assemblages of non-flying species. Stronger effect of environmental filtering was expected on the assemblages with species attaching eggs compared with assemblages of species with free eggs. We used redundancy analysis with variation partitioning to examine spatial and environmental effects on the deconstructed assemblages. As expected, the importance of environmental filtering increased and that of spatial effects decreased with increasing body size. Opposite to our expectations, assemblages of non-flying species were more affected by environmental conditions compared to assemblages of flying species. Concurring with our expectations, the importance of environmental filtering was higher in structuring assemblages of species attaching eggs than in structuring those with freely laid eggs. The amount of unexplained variation was higher for assemblages with small-sized to medium-sized species, flying species and species with free eggs than those with large-sized species, non-flying species and species with attached eggs. Our observations of decreasing spatial and increasing environmental effects with increasing body size of assemblages deviated from the results of previous studies. These results suggest differing metacommunity dynamics between within-lake and among-lake levels and between studies covering contrasting taxonomic groups and body size ranges.     

Oxidation of fat during flight of male Douglas-fir beetles, Dendroctonus pseudotsugae

During flight, male beetles lost weight primarily due to oxidation of fatty acids. RQ values of 0·7 and 0·8 were obtained for non-flying and flying insects respectively, indicating that Dendroctonus pseudotsugae is predominantly a fat utilizer, with some carbohydrate utilization during early flight periods. Selective oxidation of fatty acids was evident. The monounsaturates, C16:1 and C18:1 were oxidized at the greatest rate, followed by the saturates, palmitic (C16:0), stearic (C18:0), and myristic (C14:0) acids, respectively.     

The effect of microclimate on flying dipterans

The effect of the microclimate on the daily abundances of flying dipterans and the responses of the insects within their boundary layers have been assessed using suction traps and computer linked micro-meteorological outstations in a field experiment in northern England. Daily abundances of each family are very dependent upon the vagaries of the weather, and different families respond differently to the measured conditions; the temperature is most important for afternoon-flying families but for dusk- and night-flying families the wind speed is important, as are the climatic conditions earlier in the day. Small-bodied insects are much more sensitive to wind than are big-bodied insects. The results suggest that factors other than the measured physical ones are important in determining the distribution of flying Diptera within their boundary layers.     

Bacillus thuringiensis: a genomics and proteomics perspective

Bacillus thuringiensis (Bt) is a unique bacterium in that it shares a common place with a number of chemical compounds which are used commercially to control insects important to agriculture and public health. Although other bacteria, including B. popilliae and B. sphaericus, are used as microbial insecticides, their spectrum of insecticidal activity is quite limited compared to Bt. Importantly, Bt is safe for humans and is the most widely used environmentally compatible biopesticide worldwide. Furthermore, insecticidal Bt genes have been incorporated into several major crops, rendering them insect resistant, and thus providing a model for genetic engineering in agriculture.This review highlights what the authors consider the most relevant issues and topics pertaining to the genomics and proteomics of Bt. At least one of the authors (L.A.B.) has spent most of his professional life studying different aspects of this bacterium with the goal in mind of determining the mechanism(s) by which it kills insects. The other authors have a much shorter experience with Bt but their intellect and personal insight have greatly enriched our understanding of what makes Bt distinctive in the microbial world. Obviously, there is personal interest and bias reflected in this article notwithstanding oversight of a number of published studies. This review contains some material not published elsewhere although several ideas and concepts were developed from a broad base of scientific literature up to 2010.     

The proximal airway of the bat Tadarida brasiliensis: a minimum entropy production design

The bronchial tree of most mammalian lungs is a good example of an efficient distribution system whose geometry and dimensions of branched structures are important factors in determining the efficiency of respiration. Small and flying endothermic animals have high-energy requirements, requiring morphological and physiological adaptations to reduce energy loss. Here we show that Tadarida brasiliensis, a nocturnal small bat whose energy requirements are exacerbated by this small size and by their frequent exposure to high altitude, has a different morphology in the proximal airway, sustained by a wider trachea and better scaling factors, than other non-flying mammals. This design allows a great decrease of the volume specific resistance of the proximal airway and in consequence a very low entropy production during breathing, approximately 1/18 of that expected for a non-flying mammals of similar body size.     

Optic flow-based collision-free strategies: From insects to robots

Flying insects are able to fly smartly in an unpredictable environment. It has been found that flying insects have smart neurons inside their tiny brains that are sensitive to visual motion also called optic flow. Consequently, flying insects rely mainly on visual motion during their flight maneuvers such as: takeoff or landing, terrain following, tunnel crossing, lateral and frontal obstacle avoidance, and adjusting flight speed in a cluttered environment. Optic flow can be defined as the vector field of the apparent motion of objects, surfaces, and edges in a visual scene generated by the relative motion between an observer (an eye or a camera) and the scene. Translational optic flow is particularly interesting for short-range navigation because it depends on the ratio between (i) the relative linear speed of the visual scene with respect to the observer and (ii) the distance of the observer from obstacles in the surrounding environment without any direct measurement of either speed or distance. In flying insects, roll stabilization reflex and yaw saccades attenuate any rotation at the eye level in roll and yaw respectively (i.e. to cancel any rotational optic flow) in order to ensure pure translational optic flow between two successive saccades. Our survey focuses on feedback-loops which use the translational optic flow that insects employ for collision-free navigation. Optic flow is likely, over the next decade to be one of the most important visual cues that can explain flying insects' behaviors for short-range navigation maneuvers in complex tunnels. Conversely, the biorobotic approach can therefore help to develop innovative flight control systems for flying robots with the aim of mimicking flying insects’ abilities and better understanding their flight.     

婚飞行为影响中华蜜蜂性成熟处女蜂王的基因表达

婚飞是性成熟处女蜂王与雄蜂交配过程中的一个重要前奏, 在该过程中蜂王体内伴随着一系列重要的生理变化。为了探究中华蜜蜂Apis cerana cerana处女蜂王婚飞过程中基因表达变化, 本研究利用数字基因表达谱(digital gene expression, DGE) 技术分析了中华蜜蜂性成熟处女蜂王飞行与未飞行之间的基因表达差异。经DGE测序, 分别从两个样品中获得5.98和6.01 百万条Clean标签。通过分析检测到250个基因有差异表达, 其中133个基因在飞行蜂王中上调表达, 117个基因在飞行蜂王中下调表达。这些差异基因可以归类到348个功能性类别和142个生化途径。结果表明中华蜜蜂性成熟处女蜂王在婚飞过程中大量基因的表达发生了变化。这些结果为进一步研究中华蜜蜂蜂王婚飞过程中生理变化的分子机制提供了重要的基因表达信息。     

Asian weaver ants,Oecophylla smaragdina,and their repelling of pollinators

The Asian weaver ant, Oecophylla smaragdina, is known to have outstanding predatory power. This ant can protect the host plants from attacks of phytophagous insects and therefore has been used for biological control in the tropics. We present evidence for a possible negative effect of Oecophylla on the performance of host plants. Our observation in a fruit orchard of rambutan in Sumatra suggested that the presence of Oecohylla nests on the trees statistically significantly lowered the flower-visiting rate of flying insects, involving the major pollinator Trigona minangkabau. The visiting rate of Oecophylla workers to each flower shoot of rambutan significantly negatively correlated with the visiting rate of flying insects. Empirical evidence of such an inhibitory effect on flower-visiting of pollinators cased by aggressive ants has been scarce so far.     

Predictive model for airborne insect abundance intercepted by a continuous wave Scheimpflug lidar in relation to meteorological parameters

A Scheimpflug lidar system, based on the Scheimpflug arrangement has recently been developed and has demonstrated its ability to detect, identify, differentiate, and monitor aerial insect activity in real time and in situ. Despite the performance of such as system, making forecasts remains a challenge. The abundance of aerial insects and their distribution are determined by meteorological factors and seasonality. Based on Scheimpflug lidar data and local meteorological parameters, this study aimed to predict the abundance of airborne insects. Abundance is recorded for both dry and rainy seasons for two days, from 8 am to 9 pm. Local meteorological parameters are also recorded. The exploratory analysis of the meteorological data is carried out using principal component analysis (PCA). Statistical modeling of flying insect activity is carried out using principal, partial least square and ridge regression models. This modeling has shown that the abundance of airborne insects depended largely on the weather conditions and give relevant forecasting of airborne insects to help fighting against vector-borne diseases and to control insect-pests in crops.     

转Bt基因抗虫作物对鳞翅目非靶标昆虫生态影响的研究进展

任何转基因作物在进入商业化应用之前都必须经过严格的环境风险评价。评价转基因作物特别是抗虫作物对农田重要非靶标节肢动物的生态影响是其中一项重要内容。当前,全球种植的转基因抗虫作物大多表达对鳞翅目害虫具有活性的Cry1或Cry2类杀虫蛋白。由于非靶标鳞翅目昆虫如斑蝶、家蚕等与靶标害虫具有较近的亲缘关系,其幼虫可能同样对这类杀虫蛋白敏感。因此,这类转基因抗虫作物对非靶标鳞翅目害虫的潜在影响引起了研究者的广泛关注。在总结国内外相关研究数据的基础上,系统分析了转基因抗虫作物对非靶标蝶类和蚕类昆虫的潜在影响,获得以下结论：虽然蚕类和蝶类昆虫对Cry1或Cry2类杀虫蛋白敏感,但在自然条件下这类非靶标昆虫暴露于Cry杀虫蛋白的水平很低,抗鳞翅目害虫转基因作物的种植不可能显著影响田间蝶类昆虫的种群密度,也不会给我国的蚕丝产业带来负面影响。     

Aphid flight-track analysis in three dimensions using video techniques

Abstract. A technique is described for the three-dimensional analysis of the flight paths of small insects using two video cameras placed alongside each other with the optical axes coincident at a point some distance beyond the area of interest. The video signals were mixed and a time base introduced before recording the superimposed images from both cameras on a single VCR. With suitable lighting and a black background, flying aphids appeared on the monitor as double, bright images on a dark background. The distance between the two images was inversely proportional to the distance of the aphid from the camera lenses. A calibration grid was used to insert the correct parameters into software designed to provide the x (vertical), y (horizontal) and z (distance from the cameras) Cartesian co-ordinates for a flying insect and to calculate the distances flown, flight speed and turning parameters. The advantages of the system are that it is designed for a single VCR and monitor, provides automatic synchrony between camera signals and can examine a larger visual arena than screen-splitting methods. It operates with insects as small as aphids, and wind-tunnel studies on the black bean aphid, Aphis fabae Scop., showed that some flight parameters (for the final one-second approach to a visually attractive landing platform) differed according to whether wind was present or not. Thus, ground speed and distance moved differed significantly but turning parameters were unchanged. In addition, flight trajectory on the approach to landing depended upon initial direction of flight and the presence of wind.     

A TECHNIQUE FOR THE BIOLOGICAL EVALUATION OF INSECTICIDAL AEROSOLS

The development of a technique for testing insecticidal aerosols produced from pressure dispensers is described. The method of rearing the test insect, Musca domestica L., is given in detail.
Both free-flying and caged flies were exposed in a room of 1194 cu. ft. Six insecticidal solutions were selected for test.
The biological efficiency of each aerosol was judged on the time required to paralyse 50% of the test insects (KD 500) and on the percentage kill obtained in 24 hr. Statistical analysis of some of the estimated figures for KD 500 showed a standard error of 4–5% of the mean.
The effects of temperature, of distribution and of dosage of the aerosol on the results were investigated.
Free-flying flies were preferred, mainly because of better replication of results.
The technique adopted is described as a specification and suggestions are made for its practical application.     

Food habits of northern (Eptesicus nilssoni) and brown long-eared (Plecotus auritus) bats in Sweden

Food habits of sympatric northern and brown long-eared bats were examined by analysis of droppings collected in six maternity roosts of each species. Relatively large, nocturnal flying insects such as moths (Lepidoptera), June-beetles (Coleoptera: Scarabaeidae), crane-flies (Diptera: Tipulidae) and caddis-flies (Trichoptera), were eaten by both bat species, representing 47% (by volume) of the northern and 57% of the long-eared bat's diet. Small dipterans were important food items for the northern bat (47% of the diet) but not for the long-eared bat, which instead consumed large amounts of diurnal or predominantly non-flying taxa such as blow-flies (Diptera: Calliphoridae), earwigs (Dermaptera), spiders (Araneae) and harvestmen (Opiliones) (40% of the diet). The difference in food selection by the two species is probably due to the different foraging strategies used.     

蘑菇子实体内杀虫蛋白质的研究

许多蘑菇都对昆虫表现出毒性。为了证实与杀虫毒性有关的化合物,对14种蘑菇的毒性在水溶性、热敏性和可透析性等方面进行了研究。研究数据表明,蛋白质对大多数蘑菇子实体的杀虫活性起着重要作用,也许是一种可以用于植物抵抗害虫的基因源。在数种蛋白质中,凝集素和溶血素因不受蛋白酶的影响而成为良好的杀虫剂候选材料。