Variation in feeding behaviour of Nilaparvata lugens on resistant and susceptible rice varieties

The feeding behaviour of Nilaparavata lugens was monitored on three rice varieties showing different levels of resistance in the Philippines, using a video-assisted observation method. N. lugens made more frequent, shorter probes on the moderately resistant IR46 and resistant IR62 rice varieties than on the susceptible IR22. Honeydew production was significantly lower on the resistant varieties though insect weight gains in 24 h were similar on IR46 and IR22, both being significantly greater than on the highly resistant variety.Population development, growth index and damage ratings were low on IR62 indicating antibiosis and/or non preference. When IR46 plants were infested as seedlings population increase, growth index and damage ratings were similar to those on the susceptible IR22. When infested at a later stage of plant growth the damage rating showed a moderate level of resistance though some population development was maintained, indicating antibiosis and tolerance. N. lugens started probing less frequently after surface exploration on both resistant varieties than on IR22 suggesting the presence of a resistance factor associated with the surface waxes of these varieties.

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Résumé Le comportement alimentaire de Nilaparvata lugens sur variétés de riz, sensible (IR22), partiellement résistante (IR46) et fortement résistante (IR62), a été contrôlé avec une méthode associant la vidéo à l'observation. N. lugens faisait des piqûres plus fréquentes et plus brèves sur IR46 et IR62, que sur la variété sensible. La production de miellat était significativement plus faible sur les variétés résistantes, bien que les gains de poids des insectes aient été les mêmes en 24 h sur IR46 et IR22, les deux étant significativement supérieurs à celui sur IR62.La croissance de la population, l'indice de croissance et le taux de dégâts étaient tous plus faibles sur IR62, ce qui révèle une antibiose et/ou une absence de préférence. Quand la contamination des IR46 a au lieu au stade semis, la croissance de population, l'indice de croissance et le taux de dégâts étaient semblables à ceux de la variété sensible IR22. Quand la contamination avait lieu à un stade ultérieur, le laux de dégâts révélait un niveau modéré de résistance bien qu'une certaine croissance de population se soit maintenue, ce qui révèle antibiose et tolérance.Après exploration de la surface des feuilles des deux variétés résistantes, N. lugens sondait moins fréquemment que sur IR22, ce qui laisse présumer un facteur de résistance associé aux cires superficielles de ces variétés.

     

Electrical penetration graphs of the damson-hop aphid, Phorodon humuli on resistant and susceptible hops (Humulus lupulus)

Electrical penetration graphs (EPG's) were used to locate resistance to Phorodon humuli (Schrank) (Homoptera, Aphididae) in hops (Humulus lupulus, Cannabinaceae). Aphids on those hops showing resistance had a much reduced E2 pattern (uptake of phloem). In addition, many aphids on the resistant plants spent time non-probing within two minutes of withdrawing from the phloem. This was not observed with aphids on susceptible hops. The results suggest that resistance is located in the phloem. The involvement of a mechanical factor such as the blocking of aphid stylets, the presence of antinutritional factors, or simply an inadequate supply of nutrients, are discussed as possible resistance mechanisms.     

Responses by the brown planthopper,Nilaparvata lugens,to conspecific density on resistant and susceptible rice varieties

This study examines the nature of intraspecific interactions among Nilaparvata lugens (Stål) (Hemiptera: Delphacidae) planthoppers feeding on resistant and susceptible rice varieties. Planthopper nymphs produced less honeydew and gained less weight when feeding on rice variety IR62 (resistant) compared to susceptible rice varieties. A series of bioassays was conducted that varied N. lugens nymph densities on IR62 and IR22 (susceptible). Increasing nymph density facilitated feeding by conspecifics; however, intraspecific competition increased mortality of nymphs on IR62 (but rarely on IR22). Furthermore, nymph weights declined with increasing conspecific density on IR22, and the effects were weak on IR62. More female nymphs than males survived on IR62 but this was not affected by density. Nitrogenous fertilizer increased competition among N. lugens on young plants of IR22, but not on IR62. Results indicate that nymphs have a low efficiency in accessing resources when feeding on IR62, even where the plants have received fertilizer. Female‐biased survival and biomass compensation for mortality may promote population recovery after development on the resistant plant and accelerate adaptation to the resistant variety.     

抗性水稻品种对褐飞虱和白背飞虱种群参数的影响

在半自然状态下 ,用生命表方法初步比较了褐飞虱Nilaparvatalugens和白背飞虱Sogatellafurcif era在 4个抗褐飞虱水稻品种ASD7,IR3 6,JX89和Mudgo上的种群参数。初步的结果表明 ,白背飞虱在 4个抗褐飞虱水稻品种上具有较高的繁殖率 ,较短的发育时间和较大的种群增长。对褐飞虱各种群参数影响最大的是JX89,对白背飞虱影响最大的是Mudgo。与感性品种TN1比较 ,这些抗褐飞虱的水稻品种对 2种稻飞虱均具有不同程度的抗性。这些结果说明 ,抗褐飞虱水稻品种对白背飞虱同样具有一定的抗性 ,但白背飞虱对这种抗性具有较强的适应性 ,如果在一个地区长期推广抗褐飞虱的水稻品种 ,势必会导致白背飞虱的大发生     

Role of rice volatiles in the foraging behaviour of the predator Cyrtorhinus lividipennis for the rice brown planthopper Nilaparvata lugens

Experiments were conducted inlaboratory to study the impacts of ricegenotypes and rice plants treated withdifferent levels of nitrogen on the predationrates of the predator, Cyrtorhinuslividipennis Reuter, for eggs of the rice brownplanthopper (BPH), Nilaparvata lugens(Stål), and their relation to the ricevolatiles. In two-choice test, the predatorfemales showed different predation rates forBPH eggs on different rice genotypes, but notfor BPH eggs on rice plants treated withdifferent levels of nitrogen. The olfactoryresponse test revealed that more femalepredators oriented to the odours from healthyrice plants compared with the plain air(control); the predator preferred plant-BPHnymph complex over healthy plants, andplant-BPH gravid female complex over plant-BPHnymph complex. Additional experimentsdemostrated that there were obvious differencesin attractiveness of the healthy plants andplant-BPH gravid female complex of various ricegenotypes, while no significant differenceswere found between rice plants treated withdifferent levels of nitrogen. The results ofpredation rates of the predator on variousvarieties and plants treated with differentlevels of nitrogen were consistent with that ofits olfactory response in 5 of the 6 casesevaluated, which showed that rice volatilesplayed an important role in the foragingbehaviour of C. lividipennis.Implications for augmenting the effectivenessof natural enemies by adjusting rice attributesand cultural practices are discussed.     

A migration analysis of the rice planthopper Nilaparvata lugens from the Philippines to East Asia with three-dimensional computer simulations

Migrations of the rice planthopper Nilaparvata lugens (Stål) (Delphacidae) from the Philippines to Taiwan, southern China, and southern Japan were analyzed using three-dimensional migration simulations. The results strongly suggested that the Southeast Asian population of N. lugens mixes with the East Asian population. This highlighted the possibility that planthoppers from the Southeast Asian population, which have properties different from those in the East Asian population such as feeding of resistant rice varieties and wing polymorphism, could migrate to Japan via southern China and Taiwan. This study, therefore, emphasizes the special care that should be taken to monitor the properties of immigrants to Japan.     

Inheritance of body color in the brown planthopper, Nilaparvata lugens

The segregation frequencies of color phenotypes of F₁, F₂, and backcross progenies revealed that the body coloration of the brown planthopper, Nilaparavata lugens(Stål), exhibited multiple allelism. Monogene for color morphism exists in three allelic forms >-b ⁺ (brown or wild type), b ^o (orange) and b ^b (black). The dominance relationship was b ^b>b ⁺>b ^o. The relationship between phenotype and genotype in N. lugens was not fixed. The six possible genotypes produced eight phenotypes.

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Résumé Les fréquences de ségrégation des différentes colorations de F₁, F₂ et des croisements en retour ont montré que la coloration du corps de Nilaparvata lugens est due à un multi-allèlisme. Le monogène pour la couleur existe sous trois formes allèliques: b⁺ (brun ou sauvage), b^o (orange) et b^b (noir). Les relations de dominance étaient: b^b>b⁺>b^o. On n'a pas établi les relatios entre phénotypes et génotypes chez N. lugens. Les 6 génotypes possibles produisent 8 phénotypes.

     

褐飞虱对抗性水稻品种Mudgo个体致害性指标

在28±1℃下,观测了褐飞虱Nilaparvata lugens羽化24?h内短翅型雌成虫在敏感水稻品种TN1及抗性品种Mudgo上的寿命及体重增量。结果表明,取食抗性品种时,试虫的平均增重与寿命之间表现出明显的正相关。寿命在7天内的个体,存活期间平均体重增量为负值,而存活7天以上的个体则平均增重明显。进一步研究了初羽化的褐飞虱长翅型雌成虫在TN1及Mudgo上取食第1～4天的体重增量、寿命及产卵量,结果发现试虫在Mudgo上的这3个生物学参数之间存在明显正相关。其中,寿命及体重增量较好地反映出害虫个体对抗性品种的致害能力,可作为个体致害性指标。根据研究结果,提出将羽化后在Mudgo上存活7天以上或最初4天内体重增量大于0.1mg的雌成虫定为能够致害该抗性品种的个体。     

十六个水稻品种(系)对褐飞虱的抗虫性评价

本文通过苗期抗性鉴定、田间抗虫性鉴定、稻田节肢动物功能团优势度比较及产量测定的方法来评价16个水稻品种(系)对褐飞虱Nilaparvata lugens(Stl)的抗性。结果表明,有12个品种(系)对褐飞虱表现为抗级,2个品系表现为中抗。这14个抗虫-中抗的品种(系)在成株期也表现一定的抗虫性,且与对照TN1之间差异显著。本试验条件下,广占63-3S/华恢15、广两优106、Y58S/华15、广两优476、广占63-4S/华恢15这5个品种(系)不仅抗虫性好,而且产量也较高,分别比TN1和主栽品种扬两优6号高63.49%～66.57%和3.47%～11.57%,具有广泛的开发应用前景。     

麦长管蚜在高CO2浓度下生长的抗性与感性小麦品种上的取食行为

在加倍CO2浓度(0.7 mL/L)的人工气候箱中培养小麦感蚜品种(铭贤169)和抗蚜品种(KOK1679)幼苗30d,正常CO2浓度(0.35 mL/L)处理为对照.应用刺探电位图谱(EPG)技术对麦长管蚜Sitobion avenae (Fab.),在苗期小麦上的取食行为进行了比较研究.结果表明:蚜虫在加倍CO2浓度下生长的2个小麦品种上的取食过程中,电势降落次数(pd波个数)显著增加,刺探总时间(C波总时间)显著延长,首次出现在小麦韧皮部取食的时间(E2)显著滞后,被动取食持续时间(E2波的总时间)显著拉长.因此,加倍CO2浓度可能通过影响小麦而对麦长管蚜的取食行为产生了明显的间接影响.     

褐飞虱在香稻上的发生与产卵特征

研究褐飞虱NilaparvatalugensStl在香稻上的危害与产卵特征,结果表明香稻田中褐飞虱的自然种群密度基数远高于非香型稻。从7月22日至8月31日香稻田中褐飞虱的自然种群密度一直增长,在武香988和鄂香1号田间的若虫分别从7月22日的7头丛和3头丛上升至8月31日的126头丛和73头丛。香型稻田间的褐飞虱的自然种群密度增长慢于非香型稻田间。香稻与非香稻田间褐飞虱成虫出现的高峰日相差不大。香稻田中褐飞虱产卵株率高于非香型稻田,其中最高的为鄂香1号,达到74.27%。香稻田间株平均产卵块数几乎为非香型稻上的2倍,但是香稻上的卵死亡率(鄂香1号为39.24%)显著高于非香型稻上的(鄂中5号为27.58%,两优培九为27.21%),且产卵部位有一定差异。鄂香1号第Ⅲ叶鞘上卵块最多,占总数的60.98%,武香988的第Ⅱ和第Ⅳ叶鞘上产卵较多,第Ⅰ叶鞘上没有稻飞虱产卵。非香型稻鄂中5号上产卵最多的是第Ⅳ叶鞘,第Ⅰ和第Ⅱ叶鞘上没有褐飞虱产卵。两优培九除第Ⅰ和第Ⅴ叶鞘上没有褐飞虱产卵外,第Ⅱ、第Ⅲ和第Ⅳ叶鞘上均有褐飞虱产卵,而且卵量差异不大。     

Quantitative genetic analysis of biotypes of the brown planthopper Nilaparvata lugens: heritability of virulence to resistant rice varieties

The virulence of Nilaparvata lugens Stål (Homoptera: Delphacidae) to a resistant variety of rice, Oryza sativa L., is suggested to be under polygenic control. To determine whether the virulence of N. lugens is a quantitative character that has continuous distribution or a threshold character that has a few discontinuous phenotypic forms and is determined by some underlying continuous variable, I examined the frequency distribution of honeydew excretion that has been used as a measure of ability of attacking the rice plants, and the relationship between honeydew excretion and the oviposition rate of N. lugens females using a japonica rice line Saikai 190 which has a resistance gene Bph 1. The frequency distribution in honeydew excretion significantly differed from the normal distribution, but two distributions below and above 10 mg honeydew excretion for two days did not significantly deviate from normality, suggesting a bimodal distribution. There were significant differences in the proportion of females ovipositing and the number of eggs deposited between the female groups that excreted 0–10 mg honeydew and more than 20 mg honeydew. Within these female groups, however, the reproductive performances were not different. Thus, virulence of N. lugens can be analyzed as a threshold character that has two distinct phenotypes, virulent and avirulent. I estimated the heritabilities of the virulence of N. lugens by parent-offspring regression using the percentage of virulent females in a full-sib family. The estimates of heritability were 0.41 on Saikai 190 and 0.55 on ASD7, carrying the bph 2 gene. These results show that the N. lugens population has substantial genetic variation in virulence. The regression coefficients on female and male parents were similar, suggesting similar genetic contributions by both parents. When the parental families were examined on Saikai 190 and the progeny on ASD7, the regression coefficient approached zero. There may be a low genetic correlation between virulences to the two varieties.     

Meiosis in males of the brown planthopper, Nilaparvata lugens

Meiosis in spermatocytes was studied among the three biotypes of the brown planthopper, Nilaparvata lugens (Stål). The chromosome number, morphology, and behavior of the biotypes were similar. The autosomes divided normally, reductional for the first division and equational for the second. The X chromosome had an unstable segregation behavior; it may segregate equationally or reductionally during the first division depending on its chromatid's orientation. Metaphase I plates contained 14 autosomal bivalents and an X chromosome (14_II + X). The co-oriented sister chromatids of the X chromosome moved together to either one of the poles during anaphase I, while auto-oriented sister chromatids segregated to opposite poles. Because of the anomalous segregation behaviour of the X chromosome, metaphase II plates may both contain 14_I + X chromatid, or one with only 14_I and the other with 14_I + X chromosome. Male N. lugens has a diploid chromosome number of 29.

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Zusammenfassung Die Meiose in Spermatozyten wurde in drei Biotypen von Nilaparvata lugens (Stål) studiert. Die Anzahl der Chromosomen, die Morphologie und das Verhalten der Biotypen waren ähnlich. Die Autosomen teilten in einer normalen Weise, reduzierend für die erste und äquatorial für die zweite Teilung. Das X-Chromosom hatte ein unstabiles Teilungsverhalten; es kann sich äquatorial oder aber auch reduktional trennen, je nachdem wie sich sein Chromatid orientiert hat. Die Ebenen der Metaphase I enthalten 14 autosome Bivalente und ein X-Chromosom (14_II + X). Die co-orientierten Schwester-chromatiden des X-Chromosoms bewegen sich während der Anaphase I zusammen zu einem der beiden Pole, während auto-orientierte Schwester-chromatiden sich nach entgegengesetzten Polen trennen. Wegen des ungewöhnlichen Teilungsverhaltens des X-Chromosoms, können beide Metaphase II Ebenen 14_I und X Chromatid enthalten, oder aber eine Ebene enthält 14_I und die andere 14_I + X.

     

Brown planthopper, Nilaparvata lugens, resistance in rice cultivar IR64: mechanism and role in successful N. lugens management in Central Luzon, Philippines

We investigated the mechanism of brown planthopper, Nilaparvata lugens (Stål), resistance in the popular rice cultivar IR64, and the current level of resistance of IR64 to N. lugens in a large rice growing area with low brown planthopper populations (Central Luzon, Philippines). In greenhouse experiments with N. lugens populations collected from Central Luzon, IR64 showed slight to moderate levels of antibiosis, antixenosis, and tolerance relative to the cultivars IR22 and Azucena, which contain no major genes for N. lugens resistance. IR64 was also more resistant than IR26 in most experiments, despite the fact that both varieties have the same major gene for N. lugens resistance, Bph1. This confirms that IR64 contains one or more additional, apparently minor, genes for brown planthopper resistance. Our findings also demonstrate that, in an area with low insecticide use, it is not necessary to have high levels of N. lugens resistance, even in a rice cultivar grown by the majority of farmers, to maintain low and stable N. lugens populations.     

水稻活性成分的分离纯化及其对褐飞虱若虫的活性测定

水稻植株内的抗性次生物质是影响水稻生化抗性的主要因子之一。运用硅藻土系统溶剂分离法和硅胶柱层析分离方法分离纯化手段,从水稻(Oryza sativa L.)抗虫品种IR36甲醇粗提物中得到一种针状晶体,初步认为该晶体为一种糖甙黄酮类物质,通过该物质对褐飞虱Nilaparvata lugens(Stal)生物型Ⅱ若虫的活性测定,表明该种晶体对褐飞虱若虫的存活率、体重增加和羽化均具有显著的不良影响,不利于褐飞虱若虫的生长发育。     

Electrical penetration graphs from Cicadulina mbila on maize, the fine structure of its stylet pathways and consequences for virus transmission efficiency

Five distinct electrical penetration graph waveforms characterising the feeding behaviour of the leafhopper Cicadulina mbila Naudé (Homoptera: Cicadellidae) on maize (Zea mays L.) were obtained using a DC based system. The waveforms were distinguished by spectral features and by statistical analysis of their median voltages, durations and time to first waveform recording. By changing the polarity of the system voltage and the level of the input resistor it was shown that the waveforms are mainly determined by the electromotive force (emf) component. Based on the correlation between waveforms and the fine structure of the stylet pathways observed by transmission electron microscopy, insect's activities have been associated with five waveforms: stylet pathway formation (waveform 1), active ingestion (waveform 2), putative stylet work (waveform 3), salivation (waveform 4) and passive ingestion (waveform 5). Like waveform E1 and E2 of aphids, waveforms 4 and 5 of C. mbila correspond to feeding activities in sieve tubes. However, unlike aphids which probe briefly in non-vascular cells, waveform 2 corresponds to active ingestion in cells, where the cell content is partially ingested and hence the organelles' integrity severely affected. These observations suggest that this specific feeding feature, typical of leafhoppers, determines their ability to acquire geminivirus virions located in the plant cell nucleus.     

Wing polymorphism in Japanese and foreign strains of the brown planthopper, Nilaparvata lugens

Great variations in nymphal density and wing-form relationships occur in field populations of the brown planthopper, Nilaparvata lugens (Stål) (Homoptera: Delphacidae). When tested under uniform laboratory conditions, half of the female populations collected from 20 locations in Japan exhibited higher ratios of macropters with increasing nymphal density, but one quarter were macropterous over broad ranges of density, both types being classified as group III. Three predominantly brachypterous populations (group I) were found, even under crowded conditions and one intermediate (group II).The populations from South Asian countries, i.e. Philippines (one), Indonesia (two) and Malaysia (one) belonged to group I, but the three populations from the coastal areas of China belonged to group II. Those from Taiwan differed in responses to density; one was of group II type, and two of group III type.From these comparisons, immigration routes of N. lugens to Japan were estimated, and survival strategy of this migratory species is discussed.

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Zusammenfassung In Feldpopulationen von Nilaparvata lugens (Stål) (Homoptera: Delphacidae) gibt es grosse Variationen in der Larvendichte und in den Flügelform-Beziehungen. Unter einheitlichen Laboratoriumsbedingungen wurden diese Verhältnisse geprüft. Von 20 japanischen Herkünften zeigte die Hälfte der Weibchenpopulationen mit zunehmender Larvendichte einen höheren Macropterenanteil; ein Viertel was über einen grossen Dichtebereich macropter; beide Typen werden als Gruppe III bezeichnet. Drei Populationen wurden gefunden, die auch bei hoher Dichte vorwiegend brachypter waren (Gruppe I). Einer Zwischengruppe (II) gehörte eine einzige Population an.Die Populationen aus südasiatischen Ländern (1 aus den Philippinen, 2 aus Indonesien un 1 aus Malaysia) gehörten zu Gruppe I, die 3 Populationen aus den Küstenregionen von China jedoch zu Gruppe II. Die Populationen aus Taiwan unterschieden sich in der Reaktion auf die Dichte: 1 gehörte zu Gruppe II and 2 zu Gruppe III.Von diesen Daten werden Einwanderungswege von N. lugens nach Japan abgeleitet und die Überlebensstrategie dieser Wanderart diskutiert.