Predation and parasitism on eggs of two pod‐sucking bugs,Nezara viridula and Piezodorus hybneri in soybean

Abstract

Cohorts of newly laid egg masses of two pod‐sucking bugs, Nezara viridula and Piezodorus hybneri (Hemiptera: Pentatomidae), were exposed to naturally occurring predators and parasitoids on soybean in unsprayed fields at four sites in Northern Sumatra. The fate of the young stages was recorded until the late first instar, before the nymphs start to disperse and feed. Partial life tables showed that mortality of N. viridula until the late first instar was 50–87%, of which 18–65% occurred during the egg stage and was mainly caused by predation; 2–26% of the eggs died of parasitism. P. hybneri which was present at only two sites, showed a 73–89% mortality until the late first instar, of which 69–85% was during the egg stage and, again, mainly caused by predation; 15–24% of the eggs died of parasitism. To evaluate the role of individual egg predator species in the field, we conducted hourly observations of exposed egg masses of the two pests. Dolichoderus sp., Solenopsis geminata (Hymenoptera: Formicidae), Paederus sp. (Coleoptera: Staphylinidae) and several gryllids (Orthoptera) were most commonly encountered feeding on the eggs. An index of ‘predation pressure”; was calculated from the densities of predators in the field and from an estimate of their attack rate based on field observations of predator feeding. Two sites with low predator pressures had low predation rates, while the two sites with high predation pressures had considerably higher predation rates. The implications of the findings for IPM training in soybean are discussed.     

粉红椋鸟鸟巢结构和迁离时间防治草原蝗虫效果分析

人工招引粉红椋鸟控制蝗害是一种生物防蝗的重要手段,鸟巢结构以及粉红椋鸟迁离时间均影响其对蝗虫的防治效果。本文通过调查新疆地区不同结构的鸟巢中粉红椋鸟数量及其对鸟巢利用率,并结合粉红椋鸟迁离时间分析其对蝗虫的防控能力。结果表明,在调查的16个蝗虫发生区内,不同结构鸟巢招引效果为砖巢 > 石巢 > 天然鸟巢,砖巢、石巢和天然鸟巢招引效果分别为74.8%、71.9%和66.5%。分析粉红椋鸟迁离时间对蝗虫种群密度影响,成鸟迁离前对蝗虫的防控效果平均达58.4%,幼鸟迁离前对蝗虫的防控效果为88.8%。本文为进一步利用粉红椋鸟防治草原蝗虫提供重要理论依据。     

艾比湖地区植被分布及物种多样性研究

应用重要值计算多样性指数、均匀度指数、优势度指数,对艾比湖流域植被分布及物种多样性进行分析。结果表明：① 研究区域内可划分出10个群落,其中多枝柽柳群落(Form.Tamarix ramosissima)分布最为广泛。② 湖岸植被表现出明显的带状分布特点,并且群落物种多样性随地势发生变化,地势高的地方,物种多样性较高,均匀度较好。③ 在南北断面内,影响植物生长的主要因素为土壤含盐量。随着土壤盐分的增加,物种种类趋向单一,群落结构趋向简单。相反物种多样性随着土壤盐分的减少而增大。④ 受风况和土壤含盐量的影响,南北断面植被组成差异较大,且在近湖岸范围内,南断面植物群落物种多样性和植物生长状态明显优于北断面。     

Maize planting time and arthropod abundance in southern Mindanao,Philippines. II. Population dynamics of natural enemies

Abstract

Beneficial arthropods were monitored in monthly plantings over 4 years in a rainfed, triple-maize cropping system in southern Mindanao, Philippines. Generalist predators and two egg parasitoids of the Asian corn borer Ostrinia furnacalis (Guenée) (ACB) did not show significant differences in abundance with respect to calendar month of planting over 39 crops. Two species of Trichogramma (T. evanescens Westwood and T. chilonis Ishii) collectively parasitized 67% of ACB egg masses and 58% eggs over the study becoming more abundant as the crop aged. The closeness of the two parasitism rates suggests that to increase parasitoid efficacy, particularly early in the crop, the best strategy would be augmentation and to increase longevity of wasps by providing carbohydrate sources to extend their searching time. Unparasitized egg masses tended to be smaller showing they were more likely to be overlooked. The ratio between the two parasitoids was 56:44 in favour of the former. Trichogramma evanescens had been introduced 2 years earlier by a government project, whereas T. chilonis probably was introduced by sugarcane estates. Prior to their introduction there were no ACB egg parasitoids in the Philippines and both are firmly established as annual parasitism levels did not continue to rise during the study. Parasitoid activity caused significant reductions in neonate ACB larval numbers beginning 7 weeks after crop emergence in an average crop. Egg parasitism rates were positively and linearly correlated with ACB egg mass density. A quadratic regression model was established between mean egg parasitism rates and egg masses size with peak parasitism rates occurring at 25 eggs per mass. Collectively 32 species of generalist predators averaged 0.9 – 1.5 individuals per plant based on weekly samplings. If ants were excluded, the average dropped to 0.1 – 0.3 per plant. Ants, dominated by Solenopsis geminata (F.), fed on ACB eggs and larvae. Coccinellids as the next most numerous were represented by three species where Micraspis crocea (Mulsant) in particular tracked ACB egg masses and probably the corn leaf aphid Rhopalosiphum maidis (Fitch) as well. Four species of orthropterans also tracked ACB egg masses. The third most abundant guild was 17 spiders with the oxyopid Oxyopes javanus Thorell and the araneid Araneus inustus (C.L. Koch) highly correlated with ACB egg mass densities. Other spiders targeted ACB moths and Atherigona oryzae Malloch adults. The predatory mirid Cyrtorhinus lividipennis Reuter probably targeted the corn leafhopper Cicadulina bimaculata (Evans) and possibly thrips Thrips palmi Karny and Megalurothrips usitatus (Bagnall). The lacewing Chrysopa sp. was abundant late in the crop when aphids were present on tassels.     

内蒙古鄂尔多斯高原鸟类区系组成及其特征

2005年和2008-2009年,以样带法和固定半径样点法,对内蒙古鄂尔多斯高原鸟类区系进行了调查。调查期间共记录到鸟类168种,隶属于14目39科。其中,留鸟31种,夏候鸟73种,旅鸟60种,冬候鸟4种。繁殖鸟104种,构成鸟类区系的主体。繁殖鸟中北方型种类有92种,占繁殖鸟总数的88.5%,北方型种类占绝对优势,具有典型的古北界特征。在所记录鸟类中,有国家I级重点保护鸟类5种,国家Ⅱ级重点保护鸟类21种。调查区域主要由林地、灌丛草地、湿地、农田和居民区5种生境类型组成,调查结果表明：人类活动对鸟类区系组成有较大影响。     

Farm Scale Evaluations of herbicide-tolerant crops: assessment of within-field variation and sampling methodology for arable weeds

The Farm Scale Evaluations (FSEs) of genetically modified herbicide‐tolerant crops (GMHT) compared the effects of conventional and GMHT crop management regimes on weed densities. Weeds were sampled in quadrats at 5 distances along 12 transects systematically arranged within experimental half‐field treatment units. Weed densities declined with increasing distance from field margins. Random variation within transects was about 80% of the total within‐half‐field variation, i.e. relatively large variation at a small scale. The spatial autocorrelation between counts on the same transect declined as the distance between quadrats increased. Sampling schemes with fewer distances along transects required more transects but fewer quadrats to achieve similar precision as the 5‐distance scheme; on average 32 quadrats were sufficient. The frequency of detection of treatment effects (5% level) was little affected by using six or even three transects (30 and 15 quadrats respectively). However, the use of the 12 transects greatly improved the detection of treatment effects at 1% and 0.1% levels. The effectiveness of the reduced schemes for detecting differences between treatments (5% level) with as few as three transects compared with 12, reflects, in part, the relatively large treatment effects (e.g. 1.5‐fold or greater), which emerged for many of the sampling occasions. The FSEs provide an unusually extensive data set. Both the data and the methodology developed for their design and analysis are valuable for the planning of future weed sampling schemes.     

高山草原主要蝗虫的生物学特性

据１９８９￣１９９４年的调查研究,甘肃夏河县革加高山草原共有蝗虫３０余种,其中主要种类有狭翅雏蝗、宽须蚁蝗、红翅皱膝蝗鼓翅皱膝蝗、小翅雏蝗和邱氏异爪蝗根据发生时期的不同,可将草地蝗虫划分为早、中、晚３种类型。蝗蝻的发育历期在种类之间差异较大以早期发生的宽须蚁蝗最长,而晚期发生的小翅雏蝗最短。从孵化到成虫死亡所经历的时间,以晚期发生的种类最短。狭翅雏蝗的繁殖力在６种蝗虫中最高,每雌产卵量平均达１２５     

The effects of intercropping with cereals and minimal permethrin applications on insect pests of cowpea and their natural enemies in Nigeria

Abstract

Major insect pests and their natural enemies were sampled on cowpea in monocrop and cereal intercrop plots in southern and northern Nigeria. Populations of flower thrips, Megalurothrips sjostedti (Trybom), were reduced by 42% and predators, mostly Orius spp. (Anthocoridae), by 23% on cowpea in maize intercrop plots at Ofiki in the south. Infestation by pyralid pod borer, Maruca testulalis Geyer, was unaffected by cropping system. The results suggest that tasselling maize attracts flower‐eating beetles (Meloidae) to intercrop plots, and that pod‐sucking Hemiptera were increased by cereal intercrops at Yankara in the north. Three u.l.v. applications of permethrin at 150 g a.i./ha to monocrop cowpea reduced pest populations by 50 to 85% in the south and increased yield sevenfold. However, the sprayed crop in the north was lost due to a heavy infestation of pod‐sucking bug, Clavigralla tomentosicollis Stål, and outbreaks of Aphis craccivora Koch on sprayed plots in both localities suggested damage to natural enemies. It is concluded that the pest management potential of intercropping is variable and dependent on environmental factors, but it is recommended that intercropping be used in integrated pest management systems with the progressive decrease in insecticide use.     

内蒙古额济纳旗繁殖期鸟类群落与生态分布

2016年至2018年的5月和6月,采用样线法和样点法对额济纳旗的鸟类种类、数量和分布进行了多次调查。本项调查中共记录到繁殖期鸟类63种,隶属于18目30科,其中留鸟13种,夏候鸟42种,旅鸟8种。在繁殖鸟类中,古北界的鸟类有37种,占58.7%,鸟类区系具有典型的古北界特征。文中对该地区不同生境鸟类群结构及其之间的关系进行了分析,鸟类主要集中分布在湖泊湿地生境以及农田居民点,荒漠生境鸟类数量最少。湖泊湿地生态系统物种数、物种多样性、群落均匀度、群落丰富度均最高,荒漠生境均最低,即湿地生境是额济纳旗生物多样性存续的关键,而荒漠生境是生态恢复工程的重点区域。此外,湖泊湿地生态系统与农田生境的鸟类相似度最低,而绿洲和农田生境的相似度最高,即水资源相似的生境,鸟类群落相似性高。本项调查为阿拉善地区鸟类和生境保护提供了科学依据。     

锡林郭勒盟典型草原昆虫多样性分析

为典型草原害虫监测预警和生态治理提供理论依据,选取害虫发生相对严重的锡林郭勒盟7个旗县典型草原作为调查对象,采用Z字形扫网取样法对昆虫数量和种类进行调查,对昆虫尤其是主要昆虫蝗虫群落差异和多样性进行分析,并对蝗虫群落和环境因子进行冗余分析。结果显示,在7个典型草原区域中,正镶白旗、镶黄旗、阿巴嘎旗、西乌珠穆沁旗和锡林郭勒市的昆虫Margalef丰富度指数、Shannon-Wiener多样性指数和Pielou均匀度指数均较高,且这5个草原区域之间均差异不显著;在7个典型草原区域内共采集到草原蝗虫6科11属16种,种类较丰富,约占所有昆虫种类的20.00%;亚洲小车蝗Oedaleus asiaticus作为锡林郭勒盟典型草原蝗虫的优势种,在所有典型草原区域中的数量均高于其他蝗虫;镶黄旗和锡林浩特市的蝗虫种数最多,均为14种,而苏尼特左旗的蝗虫种数最低,为8种;植被覆盖度和海拔对蝗虫Margalef丰富度指数、Shannon-Wiener多样性指数和Pielou均匀度指数有正影响。锡林浩特市与镶黄旗的蝗虫群落相异性最小,相异性系数为0,与其他5个典型草原区域的蝗虫群落相异性也较低,相异性系数...     

Binomial sequential sampling plans for rangeland grasshoppers

Advances in sampling technology have made it possible to developbinomial sequential sampling plans for rangeland grasshoppers. Using this technique, grasshopper infestations can be rapidly classified into 'high' or 'low'categories relative to a threshold. We have developed a set of binomial sequential sampling tools, or plans, to assess the level of adult and nymphal grasshopper infestations on rangelands. The adult grasshopper plan was used to assess the level of grasshopper infestations throughout Wyoming, USA, in 1998; this resulted in a 79.5% reduction of the sampling effort. In addition, the adult sequential sampling plan was of sufficient scientific rigour to qualify some ranchers for federal disaster relief funds due to excessive grasshopper feeding. Grasshopper managers should consider using binomial sequential sampling plans wherever and whenever efficient surveys are needed to determine if grasshoppers are a threat to the production of rangeland forage and the maintenance of this ecosystem.     

宁夏麻黄山草原蝗虫及天敌对土壤含水量及坡度的响应特征

为明确宁夏麻黄山蝗虫种群、天敌种群与土壤含水量及坡度之间的关系,于2012年在麻黄山蝗区设置3个样点进行2次调查,使用土壤水分温度速测仪测量不同深度土壤含水量,通过数字高程模型获取坡度数据,以网捕目测法对蝗虫及天敌进行采集,并利用典型性相关分析法分析不同深度土层土壤含水量、坡度与蝗虫物种多样性及种群密度的关系。结果显示,在能够影响蝗虫种群的20~40 cm土层上,首次调查中土壤含水量都体现出坡顶最高、坡底最低的相似趋势;第2次调查中则在不同地形上呈现出多样化。蝗虫物种多样性与20、30 cm土层含水量关系不明显,相关系数仅为0.1306和-0.0157;蝗虫种群密度与20、30 cm土壤含水量关系也不明显,相关系数为0.0077和-0.0118。随着坡度的增加,蝗虫物种多样性与种群密度都有所下降,相关系数分别为0.7223和0.4315;坡度在30°以内的蝗虫物种多样性与种群密度都比较高,超过30°后二者急剧下降。表明在西部干旱、半干旱草原地区,土壤含水量对蝗虫种群的空间分布没有决定性影响,而坡度是影响蝗虫分布的重要因素。     

中华稻蝗胚胎发育形态、卵发育起点温度及有效积温研究

根据形态特征，中华稻蝗胚胎发育过程分为１０个阶段，本文对各阶段做了描述，绘制了形态图。利用４个不同温度的恒温箱对陕西汉中及长安两地区中华稻蝗的发育起点温度和有效积温分别进行了测定。中华稻蝗卵的发育起点温度及有效积温在汉中稻田分别为１６．７℃和２３８日度；长安县稻田为１５．７℃和２３４日度；室内饲养所收集的卵囊（长安种群）为１６．１℃和２９６日度。     

微孢子虫饵剂的不同配方对新疆草原蝗虫的防治效果

在新疆用微孢子虫对３种草原蝗虫进行室内感病性试验，结果不同种蝗虫的感病率差异很大，红胫戟纹蝗的感病率高达８３．５％，而意大利蝗和西伯利亚蝗仅分别为３４．５％和１７．７％。用飞机在草原喷洒，微孢子虫饵剂每１００克加５０％马拉硫磷４ｍｌ和１０ｍｌ，对意大利蝗和红胫戟纹蝗虫口减退率可增加到７６．７％和７６．０％，明显高于单用微孢子虫饵剂的杀虫效果。作者认为在一般蝗虫发生年份，单用微孢子虫饵剂可压低虫口到防治指标（１０头／ｍ２）以下，蝗虫发生量大的年份，采用加微量农药的微孢子虫饵剂，既可提高防效，也可比单用农药减少对环境的副作用     

新疆山地鸟类和哺乳类多样性及其区系特征

新疆各类陆栖脊椎动物近 70 0种 ,占中国这一类动物种数的 32 %,其中鸟兽资源尤其丰富 ,计有 42 5种鸟类和 1 5 5种兽类 (哺乳类 ) ,占中国鸟兽种数的 31 %。本文主要以新疆三大山区———阿尔泰山、天山、昆仑 -阿尔金山地区鸟类和哺乳类动物的多样性及区系分布作综合性介绍和分析。根据实地考察和以往文献资料 ,新疆阿尔泰山区记录在 1 2 4种鸟类 ,其中古北界北方型鸟类 5 1种 (占 41 .1 %) ,中亚型鸟类 31种 (占 2 5 .0 %) ,广布种鸟类 2 7种 (占 2 1 .8%) ,其他类型1 5种 (占 1 2 .1 %) ,显出以北方型泰加林鸟类为主的鸟类区系特征 ;分布的 5 0种兽类 ,区系上以古北界北方泰加林为主 ,即北方型兽类占该山区种数的 5 2 %。天山山区记录的鸟类大约2 81种 ,北方型种类占绝对优势 ,即北方型 1 0 6种 (占 37.72 %) ,北方广布型 76种 (占 2 7.0 4 %) ,中亚型 39种 (占 1 3.88%) ,高地型 1 8种 (占 6.41 %) ,广布型 33种 (占 1 1 .74%) ,东北型 9种 (占 3.2 1 %)。兽类分布有 62种 ,北方型兽类区系占优势 ,有 30种 (占 48.40 %) ,广布型 1 2种 (占 1 9.40 %) ,中亚型 1 1种 (占 1 7.70 %) ,特有种 9种 (占 1 4.5 0 %)。昆仑—阿尔金山地区 96种鸟类中 ,中亚类型成份占 2 8.1 %,高地型成分占 2 6%,北方型成?     

A simple tentative model of the losses caused by the Senegalese grasshopper,Oedaleus senegalensis (Krauss 1877) to millet in the Sahel

Oedaleus senegalensis is a serious pest of millet in the Sahel, but the correlation to crop loss remains largely unknown. Therefore, the correlation between densities of O. senegalensis, defoliation level and millet yields was investigated in Niger in 2008, and a simple model to foresee the yield based on these parameters was developed. The yield was significantly correlated to both the density of O. senegalensis and the defoliation level on 17 September. The best model to foresee millet yield involved grasshopper density and cumulated rainfall and may be regarded a tentative method in O. senegalensis control.     

河北省坝上红松洼草原蝗虫群落结构与多样性调查

为明确不同分区治理下河北省坝上红松洼草原生态环境对蝗虫群落多样性的影响,采用样方法于2019—2020年在不同草原类型和不同功能分区对蝗虫群落进行调查,通过丰富度、个体数、多样性指数以及均匀度指数分析蝗虫的多样性,并对不同生态因子和蝗虫多样性指标进行相关性分析。结果表明:该地区蝗虫发生种类共有5科8亚科14属25种,其中优势种是异色雏蝗Chorthippus biguttulus和北方雏蝗Chorthippus hammarstroemi。在不同草原类型中,杂草草甸和苔草Carex草甸的蝗虫群落各指标之间均无显著差异,沼柳Salix rosmarinifolia var.brachypoda灌木丛草甸的蝗虫多样性指数为0.60,均匀度指数为0.57,均显著低于杂草草甸和苔草草甸。在不同功能分区中,试验区蝗虫群落的丰富度和多样性指数分别为5.17和1.33,显著高于核心区的3.33和0.85,试验区蝗虫个体数为111.50,显著高于核心区的44.73及缓冲区的45.67;缓冲区蝗虫群落均匀度指数为0.69,显著低于核心区的0.84及试验区的0.90。植物群落对蝗虫群落有显著影响,随着植物群落物种数和个体数的增加,蝗虫群落部分指标出现降低,蝗虫群落的多样性和均匀度则显著升高,使蝗虫群落结构更加稳定;海拔对蝗虫群落结构及其多样性也有显著影响,温度和土壤对蝗虫群落结构无显著影响。     

Effect of insect pests on pod and seed yields of bambara groundnut,Vigna subterranea L. Verde in Nigeria

Field experiments were carried out at Samaru, Nigeria in the 1993 and 1994 cropping seasons to investigate the effect of insect pests on the yield of bambara groundnut. There was significant reduction in pod and seed yields of bambara groundnut in both years due to insect pests. The application of a mixture of Karate e.c. at 25 g a.i./ha and dimethoate e.c. at 400 g a.i./ha, respectively, at fortnightly intervals from crop flowering significantly increased pod and seed yields of bambara groundnut, preventing pod losses of 67% and 38% and seed losses of 71% and 43% in 1993 and 1994, respectively.     

高山草地蝗虫群落生物多样性和空间聚集强度对植物群落的响应

为明确高山草地蝗虫群落生物多样性和空间聚集强度变化及其对植物群落的响应,在位于甘肃省祁连山中段北坡的研究区调查温性草原、山地草甸和高寒草甸3类草地中的蝗虫种类和数量,对不同蝗虫群落进行生物多样性分析,并观察不同蝗虫种群的聚集程度。结果显示,共捕获蝗虫15种,8月温性草原内蝗虫虫口密度最大,为8.17头/m²,且此时Shannon-Wiener指数和Margalef丰富度指数均最大,分别为1.58和2.27;7月蝗虫群落的空间聚集程度高于其他两类草地。山地草甸和高寒草甸中蝗虫空间聚集高峰出现在8月,晚于温性草原。东亚飞蝗Locusta migratoria manilensis种群的空间聚集程度最高,其次为白边痂蝗Bryodema luctuosum、狭翅雏蝗Chorthippus dubius和小翅雏蝗Chorthippus fallax种群,鼓翅皱膝蝗Angaracris barabensis种群的聚集程度最弱。冗余分析结果显示,蝗虫群落种类组成和数量以及空间聚集强度与植物群落生物多样性、覆盖度和高度存在显著相关性。     

放牧模式对高山草地蝗虫群落生物多样性的影响及其作用机制

为明确不同放牧模式对高山草地蝗虫群落生物多样性的影响及其作用机制,本研究调查牛放牧、羊放牧、牛羊混合放牧和休牧4种模式下高山草地植物群落特征、蝗虫群落组成和数量,分析蝗虫群落生物多样性特征,利用冗余分析方法分析植物群落与蝗虫群落的相关性,采用结构方程模型分析放牧模式对蝗虫群落的影响路径。结果显示,与休牧相比,牛放牧、羊放牧、牛羊混合放牧模式显著影响高山草地植物群落高度、植物群落覆盖度和禾本科牧草高度,但对植物群落生物多样性影响不显著。4种放牧模式下共捕获蝗虫13种,不同放牧模式下,高山草地的生物指示种不同。与休牧模式相比,牛放牧、羊放牧、牛羊混合放牧模式显著影响高山草地Shannon-Wiener指数、Simpson优势度指数和Pielou均匀度指数;在牛放牧、羊放牧和牛羊混合放牧模式下,高山草地蝗虫群落Shannon-Wiener指数分别为0.36、0.35和0.29,高山草地蝗虫群落Simpson优势度指数分别为0.45、0.45和0.35,高山草地蝗虫群落Pielou均匀度指数分别为0.33、0.33和0.24。高山草地植物群落高度、覆盖度和禾本科牧草高度与红翅皱膝蝗Angaracris rhodopa、鼓翅皱膝蝗A.barabensis、青海痂蝗Bryodema miramae等呈负相关,与狭翅雏蝗Chorthippus dubius呈正相关。结构方程模型分析表明不同高山草地放牧模式主要通过改变植物群落高度间接影响蝗虫群落生物多样性。