Diapause in the European corn borer,Pyrausta nubilalis (Hübn.)

Diapause in mature larvae of the European corn borer was found to be associated with three readily discernible characteristics: (1) arrested gonadal development; (2) failure to pupate shortly after cessation of larval feeding; (3) reduction of oxygen consumption to about 25 per cent that of non-diapause mature borer larvae. Diapause was found to be induced by photoperiods of from 9 to 15·5 hr of light per 24-hr period. Within this range of photoperiods, incidence of diapause was inversely proportional to the rearing temperature employed, except that with 10·5–13·5 hr photoperiods all larvae entered diapause without regard to the ambient temperature. At moderate rearing temperature (23–25°C), the mean threshold photoperiod was 15·4 hr of light per 24 hr. The diapause threshold for photoperiods under 13 hr was not determined. The physiological changes associated with diapause were found to be largely reversible up to at least the early part of the fifth larval instar. No critical growth stage for diapause determination was detected.     

Monoamine oxidase in the brain of European corn borer larvae,Ostrinia nubilalis (Hübner)

Monoamine oxidase (MAO) activity was demonstrated in intact brains of larvae from the European corn borer, Ostrinia nubilalis using 2-(2′-benzothiazolyl)-5-stryl-3-(4′-phthalhydrazidyl) tetrazolium chloride (BSPT). With tryptamine as the substrate, MAO specific activity was restricted to mitochondria within perineurial cells. The basic BSPT methodology was modified by the substitution of 2% dimethylsulfoxide for dimethylformamide in the incubation medium. This yielded increased permeability of the brain to the incubation medium, presumably by disrupting the integrity of the blood-brain barrier. A discussion of possible reasons for the previous inability to demonstrate insect neuronal MAO activity is presented.     

Effect of amino acids on feeding behaviour of the European corn borer,Pyrausta nubilalis (Hübn.)

When incorporated in an agar-based purified diet, a number of amino acids had significant effects on the feeding behaviour of first instar larvae of the European corn borer, Pyrausta nubilalis (Hübn.). The duration of larval feeding periods was used as the criterion of the effects of the amino acids on feeding and was measured indirectly in terms of the population equilibria attained between pairs of experimental diets. Average feeding duration was increased by a number of amino acids, but most notably by l-alanine, dl-α-amino-n-butyric acid, l-serine, and l-threonine. A negative effect on feeding was observed with l-tryptophane, l-arginine, and β-alanine. The borers responded weakly to d-alanine and not at all to d-serine and d-threonine. Although the borers' response to amino acids was superficially similar to the response to sugars, different and independent sensory mechanisms were apparently involved. The effect of l-amino acids on borer feeding was found to be correlated with molecular weight and water solubility, although this property could not account for all the results obtained.     

Comparison on DNA patterns of different ecotypes of European corn borer (Ostrinia nubilalis Hübner) in Hungary

For a molecular genetic study on Hungarian populations of European corn borer L5 stage larvae were collected from 14 places of three different regions of the country (uni- and bivoltine ecotypes). Additionally, the study included larvae from Egypt, too (multivoltine ecotype). Molecular examinations of European corn borer larvae using the study of mitochondrial cytochrome b (cyt b) revealed that by single strand conformation polimorphism (SSCP) the populations found in Hungary represented the same haplotype. Even the Egyptian sample showed no genetic divergence. Some minor deviatons were found in the case of a sample from Székkutas, but that did not prove the genetic divergence of the bivoltine ecotype either, since the other samples of South-East Hungary did not display this kind of genetic variation. On the basis of our investigations it can be said that the univoltine and bivoltine generations, have uniform genetic complements.     

棉铃虫[Helicoverpa armigera(Hübner)]蛾复眼视网膜电位研究

运用视网膜电位（Ｅｌｅｃｔｒｏｒｅｔｉｎｏｇｒａｍ , ＥＲＧ） 技术研究了棉铃虫［ Ｈｅｌｉｃｏｖｅｒｐａ ａｒｍｉｇｅｒａ（Ｈüｂｎｅｒ）］ 成虫在暗适应过程中对单色光和复合光（ 即白光） 刺激的光感受性变化, 并初步分析了ＥＲＧ 的波形成分组成及影响因素。结果显示：（１） 依ＥＲＧ 振幅大小（ 峰－ 峰值） ,棉铃虫蛾的光谱敏感曲线在３４０ － ６０５ｎｍ 波谱内有三个大小不等的峰,其中第一峰位于绿－ 黄光区的５６２ｎｍ ,第二峰位于蓝光区的４８３ｎｍ ,第三个峰在近紫外区的４００ｎｍ ,显示其复眼至少具有三种感受器类型。（２） 一定光强度范围内, 一定日龄的棉铃虫蛾的ＥＲＧ 值随单色光和白光刺激光强度的增强而增大, 至一定光强度时增加变缓,呈近似Ｓ 型曲线式样。表明该蛾复眼具有较强的光强度自调节和适应机制。（３） 棉铃虫蛾复眼的ＥＲＧ 波形成分由４ 个部分组成：开光反应、正相电位、持续负电位和闭光反应,波长、光强度及光刺激时程对其各成分有不同影响。     

Comparative ultrastructure and blood-brain barrier in diapause and nondiapause larvae of the European corn borer Ostrinia nubilalis (Hübner)

Ultrastructural examination of diapause and nondiapause larval brains of the European corn borer disclosed anatomical differences that may be related to the insect's "blood-barrier". The perineurial type I cells are quite closely appressed in the diapause brain, but thrown into extensive folds with large intercellular spaces in the nondiapause brain. The perineurial type II cells of diapause and nondiapause larvae are basically similar in general ultrastructure, and most likely form the basis for the "blood-brain barrier." Horseradish peroxidase penetration studies indicated that the outer margin of the perineurial type II cells constitute the limits of infiltration into the brain. An enzymatic component of the "blood-brain barrier" is postulated in this insect. The localization of ATPase in the perineurial type II cells indicates that energy-requiring regulatory mechanisms may be localized here. Metabolic studies with isolated brains, coupled with recent evidence from mammalian systems, suggest that glial cells may be of importance in an enzymatic "blood-brain barrier."     

中国绢螟属(Diaphania Hübner)记述

一、前言 绢螟(Diaphania Hubner,1818)在系统分类上隶属于螟蛾科(Pvralidae),拟螟亚科(Pyraustinae)。本属昆虫种类相当繁多,同时又多半是农林作物和热带经济作物上的害虫,至今全世界已经记述过的种类约在四百余种左右。这类螟蛾成虫一般皆是小形至中等大小的蛾类,翅面半透明,色泽鲜艳,绚丽夺目;于阳光或灯光照耀下,五彩缤纷,尤似丝     

Insecticidal Activity of Bacillus thuringiensis Cry1Bh1 against Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae) and Other Lepidopteran Pests

Bacillus thuringiensis is an important source of insect resistance traits in commercial crops. In an effort to prolong B. thuringiensis trait durability, insect resistance management programs often include combinations of insecticidal proteins that are not cross resistant or have demonstrable differences in their site of action as a means to mitigate the development of resistant insect populations. In this report, we describe the activity spectrum of a novel B. thuringiensis Cry protein, Cry1Bh1, against several lepidopteran pests, including laboratory-selected B. thuringiensis-resistant strains of Ostrinia nubilalis and Heliothis virescens and progeny of field-evolved B. thuringiensis-resistant strains of Plutella xylostella and Spodoptera frugiperda. Cry1Bh1 is active against susceptible and B. thuringiensis-resistant colonies of O. nubilalis, P. xylostella, and H. virescens in laboratory diet-based assays, implying a lack of cross-resistance in these insects. However, Cry1Bh1 is not active against susceptible or Cry1F-resistant S. frugiperda. Further, Cry1Bh1 does not compete with Cry1Fa or Cry1Ab for O. nubilalis midgut brush border membrane binding sites. Cry1Bh1-expressing corn, while not completely resistant to insect damage, provided significantly better leaf protection against Cry1Fa-resistant O. nubilalis than did Cry1Fa-expressing hybrid corn. The lack of cross-resistance with Cry1Ab and Cry1Fa along with independent membrane binding sites in O. nubilalis makes Cry1Bh1 a candidate to further optimize for in-plant resistance to this pest.     

Modeling Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) damages on cotton

We studied and modeled damage caused by Helicoverpa armigera larvae on cotton with the aim of developing a coupled crop pest model. Two damage components were studied: the voracity (quantity of fresh matter and number of organs consumed) and feeding preferences (type of organ infested). The laboratory no-choice study of voracity on excised squares and bolls revealed that an H. armigera larva consumes 2,856 mg of fresh matter throughout its larval life, with the sixth instar consuming 86% of this quantity. This consumption rate corresponded to 23.6 squares, or 7.8 bolls. We developed equations to predict the quantity of fresh matter uptake from an individual plant organ, according to the organ mass and the larval instar. The field study of feeding preference confirmed previous findings that larvae prefer squares to bolls, with this preference decreasing as the larval age increases. However, no significant relationship was noted between the age of larvae and the size of infested organs within each organ class (square or boll). We developed a logistic model to predict the probability of a larva infesting a boll rather than a square. According to this model, the relative organ availability in the field and the larval instar were found to be significant factors.     

External antennal morphometry of Trichoplusia Ni (Hübner) (Lepidoptera: Noctuidae)

A detailed morphometric analysis of the antennae of male and female Trichoplusia ni (Hübner) is presented, based on light and scanning electron microscopic observations. These measurements of general antennal dimensions and the number, distribution, dimensions, and surface features of the antennal sensilla are applied in the consideration of olfactory transduction processes and in the derivation of a mathematical representation of the antennal surface. The surface area and the number of sensilla on the antennal flagellum are found to vary with the weight of the pupa and adult moth. The long Type 1 sensilla trichodea are hypothesized to be innervated by pheromone-sensitive olfactory cells on the basis of morphological comparisons with sensilla of other insects.     

A new Melipotis Hübner from Chile (Lepidoptera: Noctuidae)

Melipotis paracellaris n. sp. (Lepidoptera: Noctuidae) from Chile is described. This species is akin to M. cellaris (Gueneé), but it may be recognized by the upperside of forewings and genitalia.     

Zum Auftreten von Kakaomotte (Ephestia elutella Hübner) und Dörrobstmotte (Plodia interpunctella Hübner) in Rohkakaolagern und Fabrikräumen der Süßwarenindustrie

In mehrjährigen Freiland‐ und Laborversuchen wurde der Einfluß auf den Populationsaufbau von Sitobion (Macrosiphum) avenae (Fabr.) und Rhopalosiphum padi L. an mit der Spelzenbräune des Weizens, Septoria nodorum Berk., besiedelten Weizenpflanzen untersucht. Neben einer höheren Sterberate der Aphiden vor dem Erreichen der Geschlechtsreife konnte eine Verkürzung der reproduktiven Phase, eine Verringerung der Anzahl der Nachkommen sowie eine Abnahme der Gesamtlebenszeit der auf infizierten Geweben siedelnden Aphiden ermittelt werden.     

Acceptability and suitability of the European Ostrinia nubilalis Hübner for Macrocentrus cingulum Brischke from Asia and Europe

We examined whether Macrocentrus cingulum (Hymenoptera: Braconidae) of Asian origin could serve as a biological control agent of the maize pest Ostrinia nubilalis (Lepidoptera: Crambidae) in Europe. M. cingulum is already present in Europe, where it does not parasitize O. nubilalis but Ostrinia scapulalis, a related species feeding on wild dicotyledons. In contrast, M. cingulum have been imported from Europe and Asia into North America (where O. nubilalis had been accidentally introduced from Europe), and does parasitize O. nubilalis there. We conducted laboratory infestations to assess host acceptability (parasitoid’s propensity to oviposit) and suitability (parasitoid’s ability to develop) of European O. nubilalis for M. cingulum of European and Asian origin, and of Ostrinia furnacalis (their original host) for Asian M. cingulum. Asian M. cingulum parasitized European O. nubilalis as readily as O. furnacalis, and developed equally well in terms of: % female cocoons, time to first emergence from the cocoon, total number of adult offspring, % female offspring and adult longevity. Adult female parasitoids were significantly larger when emerging from O. nubilalis, mixed-sex and male cocoons were significantly more and less frequent, respectively. The acceptability of O. nubilalis was significantly lower for European than for Asian M. cingulum, and its suitability was zero. Asian M. cingulum appears a potential candidate for introduction as a biological control agent of a major maize pest, European O. nubilalis, provided environmental impact studies, economic analyses, and foreseeable interactions with other biological control agents such as the egg parasitoid Trichogramma brassicae (Hymenoptera: Trichogrammatidae) are satisfying.     

PERMANENT GENETIC RESOURCES: Isolation and characterization of microsatellite loci from the European corn borer, Ostrinia nubilalis (Hübner) (Insecta: Lepidoptera: Crambidae)

Few useful microsatellites are available for population studies of the European corn borer, Ostrinia nubilalis (Hübner). An enrichment strategy was used to develop microsatellite markers for O. nubilalis, and over 500 positive clones were isolated. Seventy-five contained unique microsatellites, 10 of which were polymorphic with discernable polymerase chain reaction products. The 10 loci were surveyed for variability in 72 wild individuals from central Iowa. Five loci showed no deviation from Hardy-Weinberg proportions, and all were successfully cross-amplified in the related Asian corn borer, Ostrinia furnacalis. These loci represent a significant addition to microsatellites appropriate for population studies of O. nubilalis.     

The European corn borer,Pyrausta nubilalis (Hübn.), and its principal host plant—VI: Host plant resistance of larval establishment

A study has been made of the role of growth-inhibiting chemical factors in the resistance of certain dent corn inbreds to the establishment and survival of European corn borer larvae. The inbred lines employed were WF9, W204, W210D, W22, and W22RB. Total resistance factor activity, as determined by bioassay, was found to be in good agreement with resistance ratings of the inbreds as determined in field tests by other workers. It was found that the whorl tissues on which borer larvae of the first generation feed may contain high levels of ether-soluble resistance factors, but in most cases only low levels of ether-insoluble resistance activity. The chemical factor primarily responsible for resistance to leaf feeding was found to be Resistance Factor A (6-methoxy-benzoxazolinone). At the growth stage in which borer attack on the tassel occurs, the tassels of all the inbreds displayed very low resistance activity, and little or no intervarietal resistance was detected. After the open tassel growth stage the internodes of W22 and W22RB and the leaf sheaths of W22RB showed good intervarietal resistance activity. Other tissues tested, including ear structures, did not display appreciable varietal differences in resistance factor activity.The relative resistance of early plant growth stages compared to later growth stages was termed intravarietal resistance and some of its characteristics were determined. Resistance factor activity of whorl leaves of the borer zone was shown to decline as the tassel length increased. The activity in other borer-significant tissues did not necessarily decline as tassel length increased, however, and intravarietal resistance was not always at its maximum in the whorl stage of the different inbreds. It was shown that varietal differences in resistance factor activity were not explicable solely in terms of differences in resistance associated with the growth characteristics of the plant.There appeared to be at least three chemicals contributing to the total resistance factor activity of the corn plant. Resistance Factor A was important in the resistance of early plant growth stages, but negligible after the development of a visible tassel. Resistance Factors B and C contributed about equally to the resistance factor activity found in internode, leaf-sheath, husks, and silk tissues. It was postulated that the resistance of corn to different parasitic organisms is caused by the same complex of chemicals responsible for resistance to the European corn borer.     

Two Different Bacillus thuringiensis Delta-Endotoxin Receptors in the Midgut Brush Border Membrane of the European Corn Borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Pyralidae)

Binding of three Bacillus thuringiensis insecticidal crystal proteins (ICPs) to the midgut epithelium of Ostrinia nubilalis larvae was characterized by performing binding experiments with both isolated brush border membrane vesicles and gut tissue sections. Our results demonstrate that two independent ICP receptors are present in the brush border of O. nubilalis gut epithelium. From competition binding experiments performed with I-labeled and native ICPs it was concluded that CryIA(b) and CryIA(c) are recognized by the same receptor. An 11-fold-higher binding affinity of CryIA(b) for this receptor correlated with a 10-fold-higher toxicity of this ICP compared with CryIA(c). The CryIB toxin did not compete for the binding site of CryIA(b) and CryIA(c). Immunological detection of ingested B. thuringiensis ICPs on gut sections of O. nubilalis larvae revealed binding only along the epithelial brush border membrane. CryID and CryIE, two ICPs that are not toxic to O. nubilalis, were not bound to the apical microvilli of gut epithelial cells. In vitro binding experiments performed with native and biotinylated ICPs on tissue sections confirmed the correlation between ICP binding and toxicity. Moreover, by performing heterologous competition experiments with biotinylated and native ICPs, it was confirmed that the CryIB receptor is different from the receptor for CryIA(b) and CryIA(c). Retention of activated crystal proteins by the peritrophic membrane was not correlated with toxicity. Furthermore, it was demonstrated that CryIA(b), CryIA(c), and CryIB toxins interact in vitro with the epithelial microvilli of Malpighian tubules. In addition, CryIA(c) toxin also adheres to the basement membrane of the midgut epithelium.     

Endophytic beauveria bassiana (balsamo) vuillemin in corn: The influence of the plant growth stage and ostrinia nubilalis (hübner)

A conidial suspension of the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin, was injected into corn plants at anthesis to suppress populations of the European corn borer Ostrinia nubilalis (Hübner) (Lepidoptera: Pyralidae). The fungus colonized the plants and moved, primarily upward, within the pith, possibly along with plant photosyn‐thates. Beauveria bassiana injected into the corn plants significantly reduced the amount of European corn borer tunneling. Colonization of corn plants by B. bassiana was independent of European corn borer infestation. The impact of environmental conditions on the movement and colonization of the plants by B. bassiana is discussed.     

Anatomy of the neurosecretory cells in the cerebral and subesophageal ganglia of the female European corn borer moth,Ostrinia nubilalis (Hübner) (Lepidoptera: Pyralidae)

The anatomy of the neurosecretory cells in the brain-subesophageal ganglion complex of female European corn borer moth Ostrinia nubilalis (Lepidoptera: Pyralidae) was studied using histological and cobalt backfilling techniques. Histological staining revealed the presence of 2 median and one lateral neurosecretory cell groups in the brain. These brain neurosecretory cells are made up of mainly type A cells with a few type B cells in the median group. Three type C neurosecretory cell clusters occupy the apparent mandibular, maxillary, and labial neuromeres at the ventral median aspect of the subesophageal ganglion. Axonal pathways of the neurosecretory cell groups were delineated by retrograde cobalt filling from the corpora cardiaca. Fibers of the 3 brain neurosecretory cell groups merged to form a distinct axonal tract that exits the brain via the fused nervi corporis cardiaci-1 + 2. Cobalt backfilling from the corpora cardiaca filled 4 groups of cell bodies in the subesophageal ganglion. The presence in the subesophageal ganglion of extensive dendritic arborizations derived from the brain suggests interactions between neurosecretory cell groups in the 2 head ganglia.