Facultative diapause, a strategy that allows insects to initiate additional generations when conditions are favorable or to enter diapause when they are not, has a profound effect on the ecology and evolution of species. Most previous studies have concentrated on the role of photoperiod and temperature in inducing facultative diapause in insects. In contrast, here we studied pupal diapause mediated by larval host plants in the cotton bollworm Helicoverpa armigera, and confirmed that pupal weight is a critical factor. Two groups of third instar H. armigera larvae, kept at 25 °C with L:D=8:16 and 20 °C with photoperiod of L:D=8:16, respectively, were fed on six host plants and on artificial diet (as a control) to determine how larval host plants affect diapause incidence and related traits (such as pupal weight and developmental duration). The data showed larval host plants affected diapause incidence significantly and the effects could be masked by low temperature. Further analysis showed that pupal size, not the length of the sensitive stage, affected the decision to enter diapause. In a further experiment, third-instar to final-stage larvae deprived of artificial diet for 2 days demonstrated a direct relationship between pupal weight and diapause incidence. These results suggest that larval host plants, by affecting pupal size, may influence diapause occurrence in H. armigera. This has important adaptive significance for both over-wintering survival and the possibility for completing an additional generation.

为了深入分析和探讨昆虫发育与环境温度的关系, 在恒温(15~37℃)和交替变温(12/18~34/40℃)下测定了棉铃虫Helicoverpa armigera蛹的发育历期(d),分别用线性模型和非线性模型(Logan模型﹑Lactin模型和王氏模型)拟合其发育率(1/d)数据.结果表明,这3个非线性模型能更准确地描述发育率与温度之间的曲线关系,判定系数(R2)在0.9878～0.9991之间.对全部观测数据的进一步研究表明,只要有6个分布合适的观测数据,就可以用这些非线性模型获得相当满意的估测效果.如果缺乏高温下的测定数据,用非线性模型预测的昆虫发育率可能失真.分析了蛹在恒温和变温下发育率差异的可能原因,讨论了应用这3个非线性模型预测蛹期发育的优点和缺点,指出用非线性模型取代线性日·度模型进行害虫发生预测和益虫饲养管理的合理性和必要性.

BACKGROUND: Helicoverpa armigera (Hubner) is one of the most important pests in many countries. Spinosad is used widely for the control of pests, but there is sparse information available regarding its sublethal effects on H. armigera. Here, the authors attempt to investigate the sublethal effects of spinosad on H. armigera in order to reveal the negative, non-lethal impact of insecticides on this pest.RESULTS: The toxicity of spinosad against H. armigera was determined under laboratory conditions by oral exposure of late second-instar larvae to the compound. The 48 h LC50 and 72 h LC50 values of spinosad to this pest were found to be 0.41 mg kg(-1) and 0.35 mg kg(-1) respectively. Spinosad at sublethal concentrations significantly extended the developmental time of survivor larvae, and reduced larval wet weight. Post-exposure effects were indicated by decreased pupation ratio and pupal weight, by prolonged prepupal and pupal periods and by decreased emergence ratio, fecundity and longevity of adults.CONCLUSION: These results suggest that the combination of lethal and sublethal effects of spinosad might affect pest population dynamics significantly by decreasing its survival and reproduction, and by delaying its development. (C) 2008 Society of Chemical Industry

Laboratory colonies of cotton bollworm larvae, Helicoverpa armigera, kept at 20°C under a photoperiod of L:D=10:14 were fed on five host plants (cotton, corn, kidney bean, tobacco and tomato) and an artificial diet (control) to determine the effects of larval host quality on survival and pupal over-wintering preparedness. A separate experiment showed that diapausing pupae weighed more and contained greater nutrient stores than did non-diapausing pupae. Diapausing pupae reared on different host plants showed significant differences in terms of over-wintering reserve storage, and degree of cold-hardiness (extent of low-molecular-weight substances and SCPs), and survivorship. The more nutrients the host plant had, the more the pupae weighed and the higher the levels of total lipids and glycogen. Body water content was also significantly affected by larval food quality. The mean pupal super-cooling capacities varied significantly from −16.7 to −18.9°C according to host plants the larvae feed on, and these significantly related to water content, pupal weight, lipid and glycogen content, and the levels of glycerol. Levels of trehalose, glycerol, and inositol, which were mainly low-molecular-weight substances, showed no significant differences among different host plants, except for trehalose. Pupal mortality varied from 39.7% on corn to 3.3% on the artificial diet, which was significantly related to pupal weight, total lipid content, trehalose levels, and super-cooling points. These results suggest that larval food quality can affect survival and influence the over-wintering preparedness of the cotton bollworm.

Summer diapause in the cotton bollworm, Helicoverpa armigera (Hübner), which prolongs the pupal stage, particularly in males, is induced by high temperatures. In the laboratory, summer-diapausing pupae of H. armigera were induced at high temperatures (33–39°C) with a photoperiod of LD8:16; winter-diapausing and non-diapausing pupae, cultured at 20°C with a photoperiod of LD8:16 and at 27°C, LD16:8, respectively, acted as a control. Retention time of eye spots, weight, and lipid and glycogen levels were compared. At high temperatures, both body weight and energy storage capacity were much higher in summer-diapausing pupae than in non-diapausing pupae reared at 33–39°C. At temperatures (>33°C) high enough to maintain summer diapause, the eye spots of summer-diapausing pupae did not move during the 30-day experiment. However, eye spots of summer-diapausing pupae placed at 30°C began to move about 10 days after they were transferred, significantly later than in non-diapausing pupae reared at 33–39°C or non-diapausing pupae reared at 27°C, which initiated eye spot movement 2 days after pupation. The differences in retention time of eye spots between summer- and winter-diapausing pupae shows that winter diapause is more intense than summer diapause in this insect. The weight loss, and lipid and glycogen metabolism curves indicate that the summer-diapausing pupae's metabolism is very low. We conclude that summer diapause in the cotton bollworm is a true diapause and that the summer diapause enables the cotton bollworm to withstand the high temperatures of summer.

长期以来,国内有关文献一直将番茄列为烟青虫Helicoverpa assulta的寄主植物,但田间调查结果往往与此矛盾,本研究的目的是阐明番茄是否为烟青虫的寄主植物.室内试验表明,虽然烟青虫成虫在盆栽番茄植株上产卵较多,但无论是用番茄离体嫩叶还是用盆栽植株饲养,初孵幼虫绝大部分在1龄死亡,平均存活时间很短,不会对番茄造成有经济意义的危害;即使用番茄青果饲养的3龄幼虫也不能活到6龄.根据人工饲料饲养结果估测,番茄苷对初孵幼虫的致死中浓度LC50为0.0744%,叶和青果中报道的番茄苷含量已接近或超过此水平,这是幼虫不能存活的主要原因之一.田间调查也表明,烟青虫并不危害番茄.因此,番茄不是烟青虫的寄主植物.文献中的记载很可能是将棉铃虫误判为烟青虫.

Three indices often appeared in the literature, species richness, Simpson's index, and Shannon-Wiener index for estimation of insect diversity is introduced. The correct expressions of Shannon-Wiener index and evenness with the English code is also briefly discussed.

The development, body weight, survivorship, and reproduction of the cotton bollworm, Helicoverpa armigera (Hubner), were evaluated in the laboratory at 27degreesC and photoperiod L:D = 14:10 on six host plants: cotton (Gossypium hirsutum L.), corn (Zea mays L.), tomato (Lycopersicon esculentum Mill), hot pepper (Capsicun frutescens L.), tobacco (Nicotiana tobacum L.), and common bean (Phaseolus vulgaris L.). Cotton bollworm larvae successfully survived on all six host plants, although mortality was very high on hot pepper and tomato. The developmental time of immature stages ranged from 26.6 d on corn to 35.1 d on tomato. Body weight of young fourth instar larvae ranged from 22.8 mg on corn to 5.9 mg on tobacco, while body weight of young last instar larvae and pupae ranged from 176.7 mg on cotton to 132.5 mg on tomato, and 285.2 mg on corn to 167.1 mg on tomato, respectively. Immature survival from egg to pupa varied from 33.1% on cotton to 1.7% on hot pepper. The average number of eggs oviposited by adults reared on cotton, corn, common bean, tomato, hot pepper, and tobacco were 708.4, 784.8, 778.1, 559.1, 562.5, and 314.3, respectively. The net reproductive rate of this species, measured from egg to egg, varied from 117.6 on cotton to 5.1 on hot pepper. We conclude that H. armigera can complete their life cycle on all six host plants, although tomato and hot pepper were relatively unsuitable.

Summer diapause in the cotton bollworm, Helicoverpa armigera (Habner), is prolongation of the pupal stage, particularly in males, induced by high temperatures. The effects of exposing a parental generation to temperatures of 33 to 39degreesC on the development, survivorship, longevity and fecundity of their offspring were determined in the laboratory. Three groups of offspring were examined: A, the progeny of control female moths reared as larvae at 27degreesC mated to mate moths that had undergone summer diapause when exposed to high temperature; B, the progeny of control female moths mated to males that had not undergone summer diapause after exposure to high temperature; C, the progeny of control females mated to control males reared at 27degreesC. The developmental times of the immature stages were significantly different between groups. The survival rate in the immature stages varied significantly from 69.8% (Group C) to 34.7% (Group B). The average number of eggs produced per female and the longevity of females and males were not significantly different. The indices of population increase of Groups C, A and B were 286.2, 256.8 and 145.0, respectively. These results indicate that Group A offspring had physiological advantages, such as survival and population increase, compared to Group B offspring. The adaptive significance of summer diapause in the cotton bollworm is discussed in relation to the performance of offspring.

昆虫的功能反应是指每头捕食者在一定时间内的捕食量对猎物密度变化的反应.该文介绍描述这种功能反应的圆盘方程(Ⅱ型)的由来及其参数的估测方法,简要讨论了影响昆虫功能反应测定的主要因素.

在预蛹期,高温处理能诱导棉铃虫蛹进入夏滞育.本实验着重就33～39℃的变温下滞育蛹和未滞育蛹的失重动态进行了对比研究,同时以常温(27℃)下蛹作为参照.研究发现:在33～39℃的变温条件下,棉铃虫化蛹率显著低于其在常温下的化蛹率,且所化蛹中有63.2%的雄性和10.9%的雌性进入高温夏滞育,其中高温滞育蛹和未滞育蛹分别都轻于正常发育蛹.化蛹后第2日至第5日期间,高温滞育蛹失重量显著低于高温未滞育蛹和正常发育蛹的失重量,分别为3.62、13.30和5.49mg;蛹期总失重量结果与化蛹后第2～5日间蛹失重量趋势一致,高温滞育蛹、未滞育蛹和正常发育蛹失重量分别为15.60、49.35和26.30 mg.蛹失重动态研究发现高温滞育蛹在夏滞育期间其失重曲线平缓,显著低于高温未滞育蛹和正常发育蛹;高温滞育蛹滞育解除后,其失重曲线与正常发育蛹的失重趋势基本一致.结果表明,棉铃虫夏滞育蛹能通过维持低的代谢水平来度过不利环境,具有一定的生态适应意义.

归纳了与昆虫学有关的科学期刊英文刊名的缩写规则,列举了刊名中常见单词的缩写方法和常见刊名的缩写形式,讨论了在缩写刊名时可能出现的问题.

几十年来对昆虫夏滞育的研究不断深入,阐明了不少昆虫夏滞育的生态机理.目前,探讨其内在的机制已成为研究的方向.该文着重论述夏滞育的生理生化特征、夏滞育的调控及其遗传基础.

夏滞育作为昆虫越夏的生态策略 ,已广泛引起昆虫学家的重视。本文就几十年来夏滞育研究的进展进行综述。着重讨论诱导、维持、终止夏滞育的主要环境因子 ,夏滞育的生态特征和它的生态适应意义。

Performance and body water dynamics in the pupal stage of the cotton bollworm, Helicoverpa armigera, were investigated at 25deg C and relative humidities (RH) of 0%, 9%, 22.5%, 80%, 92%, and 100%. The non-diapause pupae failed to emerge at RH≤9% and about 20% of them succeeded in eclosion at 22.5% RH. The high humidities showed little influence on their survival. The diapausing individuals rarely died at all the humidities tested except 0% RH for 30 days, during which the diapause termination percent obviously increased wit decreasing humidity. Significant linear relationship were found between the rate of cumulative water loss in both diapause and non-diapause pupae since one-day-old and their ages in day. The non-diapause pupae that died at each of the low RHs lost more than 32% of their body water on the day before death. The mean water loss in the diapausing specimens at 0% RH for one month averaged 22.4% and those at RH≥90% did not exceed 3.6% in the same period.

Abstract A new and practical artificial diet for the cotton bollworm, Helicoverpa armigera (Hübner), containing canned tomato paste has been developed. The developmental duration of larvae fed on the diet was greatly shortened because most of them only went through 5 stadia before pupation. To add certain amount of mung bean flour to partly substitute for wheat germ in the diet was beneficial to the adult reproduction. During rearing period of 12 successive generations, 87. 5%‐98. 7% of the larvae survived and only less than 5 % of the pupae failed to emerge. The number of egg laid by the adults of the 11th generation averaged about 1 000/female, with a hatching rate of 86. 5%. These results suggested that the vitality of the cotton bollworm did not decline obviously after reared with the diet for two years.

Abstract Performances of the aphid, Myzus persicae, were monitored during feeding on leaves of the rape, Brassica chinensis, previously fumigated with SO2 in a range of concentrations between 20 and 160 nl/1 at 25°C. Response of the aphids depended on dose of the air pollutant. Moderate dose of SO2 treatment on the rape greatly enhanced the aphids' performances while high level of the pollutant heavily suppressed their growth and reproduction. They performed best at about 80 nl/l SO2, where nymphal mean relative growth rate (MRGR), adult fecundity and intrinsic increase rate(rm) of the population increased by 31.5%, 89.8% and 42. 7% over those of control aphids, respectively. Determination of the plant chemistry suggests that the altered relative content of methionine induced by So, exposure might be responsible for this response of dosage dependence.

A series of experiments using open-top fumigation chambers was carried out to investigate the effect of SO2-polluted rape on performance of the turnip aphid, Lipaphis erysimi (Kaltenbach). Proper SO2 concentrations significantly enhances growth and reproduction of the aphid. Nymph MRGR and adult fecundity reached their maxima at 116 nl/L and 80 nl/L of the pollutant, respectively. Potential of the population growth got fully displayed at the latter dose because the highest survival rate of the nymphs also took place at this concentration. It is suggested according to changes in the plant chemistry that this indirect effect of SO2 pollution on the turnip aphid might involve variation in content of individual key free amino acid rather than total amount of all the amino acids in the leaves induced by the air pollutant.

he age-stage-specific life table that incorpolates variable developmental rateamong individuals and male adults is reported for the armyworm, Mythimna sepa-rata (Walker), reared on young corn leaves at 23°c. The method of its constructionis diagramed, according to which, the net reproduction rate of the worm population(R0) was calculated to be 155.88; the intrinsic rate of increase (rm), 0.1120; andthe mean generation time (T), 45.08 days. All values of these parameters are somewhatdifferent from those obtained by means of the traditional age-specific life table,and the cause of such differences is analysed. Advantage of the new life table incomparison to the traditional one is briefly discussed.

An artificial diet with lamb's quarters, Chenopodium album L. and wheat germ as its major ingredients was developed to rear larvae of the turnip moth, Agrotis segetum Schiff. for 16 successive generations. During the rearing period, 87-96% of the neonate larvae successfully pupated, of which less than 5% failed to emerge. Egg production of moths from diet-fed caterpillars averaged 1,000, with about 90% of the eggs hatching. A rearing technique for assuring a high survival rate, and performances of turnip moths under different rearing conditions are described.