应用灰色系统理论探讨瓢虫的迁飞和蚜虫的防治

在多年的探索中蔡晓明等人首次提出了中国七星瓢虫迁飞的假设,不仅从理论上做了论证,而且与实际现象相当符合。在一定的地面和高空的气象条件下就有迁飞的瓢虫出现,因此,在北方考虑蚜虫的防治时应当考虑瓢虫迁飞的因素,利用迁飞而来的瓢虫去防治蚜虫。由于有些因子之间的关系是灰色的,所以本文应用灰色系统理论做了探讨。从所得结论可看出用灰色系统理论探讨瓢虫迁飞与蚜虫防治的相互关系与人们的感性认识是一致的。     

郑州第三代稻纵卷叶螟成虫迁入和天气条件的关系

害虫迁飞规律的揭示为害虫的预测预报工作开拓了新的探索领域,许多昆虫学工作者和气象工作者致力于气象因素与迁飞关系的研究,进行害虫长期数量预报。赵圣菊(1984)建立了粘虫一代发生区的发生期、发生量的长期预报模式.宋祥燕(1983)分析了迁飞的气象条件,作了稻纵卷叶螟迁飞期、迁飞量的预报尝试。程极益等(1985)用PC-1500微型机以3—5月的气象资料作为参量预报稻纵卷叶螟的发生程度。我们为了预报郑州地区第三代稻纵卷叶螟成虫迁入数量,用IBM电子计算机分析了1978—1985年的气象资料和虫情资料,筛选了主要生态因素,组建了预报方程。材料和方法稻纵卷叶螟(Cnaphalocrocis medinalis)     

多异瓢虫与七星瓢虫、大草蛉不同虫态间的集团内捕食

多异瓢虫、七星瓢虫和大草蛉是控制蚜虫重要的广谱捕食性天敌昆虫,为明确这些昆虫间的集团内捕食效应与个体发育阶段的关系,观察了多异瓢虫与七星瓢虫、大草蛉各虫态(蛹除外)之间的集团内捕食效应。设置30个虫态(虫龄)组合处理,于温室盆栽棉花(无蚜虫)上接种等量的试虫,观察24 h后的存活数量。结果表明,当参与双方的虫态不同时,晚期虫态的存活数量显著大于早期虫态;当参与双方的幼虫龄期不同时,高龄幼虫的存活数量显著大于低龄幼虫;成虫对卵、1龄和4龄幼虫的捕食程度随虫龄增大而呈抛物线增大,存在显著的二次函数关系。当参与双方的虫态(龄)相同时,多异瓢虫成虫的存活数量显著小于七星瓢虫,但大于大草蛉成虫;多异瓢虫幼虫(1龄和4龄)的存活数量显著小于大草蛉,而与七星瓢虫没有显著差异。研究结果说明,在没有集团外猎物(蚜虫)存在的情况下,多异瓢虫与七星瓢虫、大草蛉之间的集团内捕食效应只在参与者的虫态或虫龄不同时取决于发育阶段,而当参与者虫态或虫龄相同时,还取决于其他因素。     

七星瓢虫在农业上的应用

瓢虫在我们生活中到处可见。它属于鞘翅目的一类昆虫,其绝大部分是益虫。在农业生产中,利用捕食性瓢虫的幼虫和成虫均可防治蚜虫、介壳虫、螨类以及许多其它害虫的卵和幼虫。早在1888年,由于美国在加利福尼亚州引进澳洲瓢虫,防治柑桔上的毁灭性大害虫吹绵介壳虫获得完全成功,引起各国的重视,从此以虫治虫的生物防治法开始蓬勃发展起来。我国也曾利用澳洲瓢虫与大红瓢虫防治柑桔吹绵介壳虫获得成功。近年来北方棉区利用瓢虫防治棉蚜取得良好成绩。北方农田常见的捕食性瓢虫有:七星瓢虫、十三星瓢虫、龟纹瓢虫、多异瓢虫、二星瓢虫等等,其中以七星瓢虫的利用最为广泛。据河北省植保土肥所统计,该省在1976年曾利用七星瓢虫防治棉蚜的面积达150万亩,效果很好,持续控蚜期长,有许多效果更好的棉田甚至可以不用化学农药来治蚜。     

6种复配杀虫剂对七星瓢虫的毒力测定及风险评估

采用药膜法分别测定了10％甲维盐·茚虫威悬浮剂、12％甲维盐·虫螨腈悬浮剂、12％虫螨腈·虱螨脲悬浮剂、14％呋虫胺·螺虫乙酯悬浮剂、22％吡虫啉·螺虫乙酯悬浮剂和6％吡虫啉·高效氯氟氰菊酯悬浮剂6种复配杀虫剂对七星瓢虫Coccinella septempunctata Linnaeus幼虫急性毒性,并进行了初级风险评估.结果 显示,6种药剂对七星瓢虫48 h的LR5o(半致死用量,Median lethal rate)分别为0.812、2.255、4.082、22.735、6.755和0.00467 g a.i/hm2.在农田内暴露场景下,6种复配杀虫剂对七星瓢虫风险均不可接受;在农田外暴露场景下,仅有14％呋虫胺·螺虫乙酯悬浮剂和22％吡虫啉·螺虫乙酯悬浮剂对七星瓢虫风险可接受,其它均不可接受.结果 表明在田间最大推荐用量下,6种药剂对七星瓢虫的初级风险评价均存在高风险.     

七星瓢虫基础研究现状

七星瓢虫对蚜虫等农林业中的重要害虫有较强的控制作用,利用七星瓢虫进行控害的生物防治技术正在逐步推广。本文就七星瓢虫的生物学特性、捕食、对农药的反应以及人工饲养等方面进行综述:七星瓢虫幼虫随龄期增长逐渐出现黄斑,温湿度对生长发育影响较大,以成虫越冬,有滞育现象。七星瓢虫捕食性强,捕食对象较多,包括多种蚜虫、木虱、蚧虫、粉虱、蓟马、网蝽等,其捕食功能反应模型主要为HollingⅡ型,捕食效应受温度、光周期及其猎物密度与自身密度影响。七星瓢虫对农药有一定的选择性,农药对七星瓢虫捕食行为及其生长发育有一定的影响,并会导致其抗药性的产生。目前,七星瓢虫的饲养以昆虫材料为主,辅以人工饲料,采用低温储存,以卵卡作为商品出售。七星瓢虫的基础研究可为今后大规模运用于田间提供参考。     

南阳棉区棉虫的综合防治

1974年以来,示范推广了以利用七星瓢虫(Coccinella septempunctata L.)治蚜为主的棉虫综合防治技术,全区综防面积从1975年的近万亩发展到近年来的约90万亩;植保投资一般已由每亩七八元下降到二、三元,避免或减轻了人畜中毒及环境污染。本文着重报道七星瓢虫在棉虫综防中控制棉蚜的作用,以及棉田天敌群体得到的有效保护。     

基于两种轨迹模型的褐飞虱迁飞轨迹比较研究

异地预测是迁飞性害虫发生预测的重要内容,迁飞轨迹模拟和预测是能较好地反映害虫迁飞时空动态的一种异地预测方法。褐飞虱作为我国水稻生产上的一种重要迁飞性害虫,其迁飞轨迹的准确预报,可为其灾变预警和有效防控提供科学依据。为了比较选择一些准确性好、分辨率高、易于推广应用的害虫迁飞轨迹模型,选取2006年7月初发生在湖南省洪江市的一次褐飞虱重大北迁过程作为典型个例,运用中尺度天气研究和预报模式WRF,结合NCEP气象再分析数据,利用HYSPLIT和FLEXPART两种轨迹计算模式对褐飞虱迁飞轨迹进行模拟,并验证模型模拟和计算的准确度和精确度。研究结果表明:(1)WRF-HYSPLIT和WRF-FLEXPART两种轨迹计算模式在虫源地、迁飞路径(迁飞方位角和走向)、迁飞高度、迁飞速率和迁飞距离计算上总体趋势一致,但存在一定的差异,后者的起伏变化大于前者。(2)尽管两种耦合模式在调用WRF模式输出的预报场物理变量方面有很多相同之处,但WRF-FLEXPART耦合模式在运行计算过程中比WRF-HYSPLIT耦合模式多考虑了对流参数、地表胁迫和各种地形参数,因而能更全面地反映中尺度天气过程(特别是对流性天气过程)对昆虫起飞、空中飞行和降落的动力作用,也能更真实地反映地表物理过程、大气湍流结构和地形起伏对褐飞虱种群迁飞的影响。(3)从褐飞虱种群对生境和取食条件选择上看,两种模式模拟的各高度迁入种群的虫源区、迁飞路径和降落地都是合理的、准确的。但从褐飞虱迁出、空中飞行和降落所处的三维流场来看,WRF-FLEXPART模式轨迹走向与盛行气流方向的吻合度要明显高于WRF-HYSPLIT模式。(4)两种模式均可作为业务工具在迁飞性害虫测报中推广应用。     

不同虫态及虫龄大草蛉与七星瓢虫之间的集团内互作

【目的】为明确新疆棉田棉蚜 Aphis gossypii 捕食性天敌之间的集团内捕食效应及其对蚜虫数量的控制作用。【方法】本研究以优势天敌昆虫大草蛉 Chrysopa pallens 和七星瓢虫 Coccinella septempunctata 为对象,以棉蚜为猎物,在温室中利用盆栽棉花,首先观察了2种天敌昆虫之间各虫态及虫龄配对的19个处理在无蚜植株上共存24 h后的存活数,然后观察了2种天敌昆虫配对处理下棉苗上棉蚜数量随时间的变化趋势。【结果】在无蚜棉株上2种捕食性天敌昆虫共存24 h后的存活结果表明：（1）在发育阶段相同的配对组合中,若是成虫则均存活,若是１龄幼虫则大草蛉存活较多,若是末龄幼虫则七星瓢虫存活较多;（2）在有卵的组配中,除七星瓢虫卵不被大草蛉成虫所捕食外,其他5个组配处理中卵均被捕食;（3）在有蛹的配对组合中,除七星瓢虫蛹被大草蛉末龄幼虫捕食外,其他处理下蛹均不被捕食;（4）在成虫与幼虫的配对组合中,七星瓢虫成虫捕食较多的大草蛉1龄幼虫,但不捕食大草蛉末龄幼虫,而大草蛉成虫与七星瓢虫1龄或末龄幼虫之间不发生捕食;(5）在不同龄期幼虫的配对组合中,大草蛉末龄幼虫捕食七星瓢虫1龄幼虫,而七星瓢虫末龄幼虫捕食大草蛉1龄幼虫。在有蚜植株上2种捕食性天敌共存对棉蚜数量具有不同的控制作用：（1）2种捕食昆虫的幼虫各自单独存在（对照）下,蚜虫密度随时间而降低;（2）大草蛉幼虫与七星瓢虫幼虫或成虫配对处理下,棉蚜密度随时间而增大;（3）大草蛉成虫与七星瓢虫幼虫或成虫配对处理下,棉蚜密度随时间而减小。【结论】研究结果说明,大草蛉与七星瓢虫之间存在集团内捕食,但２种天敌共存对棉蚜的控制作用取决于大草蛉虫态, 若大草蛉为幼虫,可使蚜虫密度增大,若为成虫,则使蚜虫密度减小。     

模糊分析预报越冬代二化螟发生期

二化螟Chilosopressalis（Walker）是建宁县水稻重要害虫,尤其一代为主害代。因此,准确及时预测其发生是测报工作的重要一环。但因二化螟越冬场所和越冬虫龄的复杂性,常给测报,特别是长期预报带来困难。基层测报现常用功臣法剥查越冬代化蛹进度,预测发生期,不仅工作量大,且难于准确,无法作长期预报．为解决这一矛盾,笔者利用10年资料,从35个气象因子中,采用普查法［‘］筛选出2个预报因于：x;——当年1月份降雨量（mm）。x。——上年间月份积温阳度）,对预报对象少——越冬代二化螟蛾高峰（月、日）应用FuZZy分析［’,’］…     

Colorado beetle in the Channel Islands, 1947 and 1948

Colorado beetles can survive up to 10 days in sea water and still be capable of flying when the temperature reaches 80° F. (26·67° C.). The beetles that reached the Channel Islands in May 1947 and in May 1948 prove that they can travel across about 30 miles of sea, the approximate distance of Guernsey from the Cherbourg peninsula. The invasions occurred as a result of migrant beetles from the Cherbourg peninsula which dropped on the sea between the Channel Islands and the French coast and drifted ashore.     

Sea water transport and submersion tolerance as dispersal strategies for the invasive ground beetle Merizodus soledadinus (Carabidae)

The alien ground beetle Merizodus soledadinus was introduced to the sub-Antarctic Kerguelen Islands in 1913. It colonized several small islands and islets of this archipelago, without any apparent human assistance in some locations, and crossed several large rivers and alluvial plains. As aggregations of this species on the tidal drift line are common at the Kerguelen Islands, the present work examined whether adult individuals of M. soledadinus could disperse by flotation on the sea. Different sample sizes of ground beetles (from 1 to 10) were placed on sea water at 8°C in plastic vials. Survival (50% lethal times) significantly increased from 2.1 ± 0.2 days for single beetles to 6.5 ± 0.3 days for groups of 10 beetles per vial, with there being no difference in the survival duration for groups of 2, 5, and 10 beetles per vial. Similar survival durations were found for beetles in vials with artificially agitated water and controls. In addition, the duration of survival was twice as high under freshwater versus sea water conditions, when groups of 10 adults were used. Finally, the survival to total submersion in freshwater was evaluated, and ranged from 3 to 4 days. This ability to survive extended periods both floating on and/or submerged beneath salt and freshwater conditions, indicates the presence of a successful dispersal mechanism, which may facilitate the dispersal range of M. soledadinus across the Kerguelen Islands, comprising over 300 islands and islets in total.     

THE BEHAVIOUR OF ADULT CLICK BEETLES OF THE GENUS AGRIOTES (A. OBSCURUS L., A. LINEATUS L., AND A. SPUTATOR L.)

Various methods of trapping click beetles were tried, the aim being to devise a method which could be used for population and movement studies in grass fields. It is shown that a trap consisting of a 3 in. thickness of hay over closely clipped grass is suitable for this purpose. Annual and daily activity are discussed. Maximum activity occurred in late May and early June, and during the afternoon and evening. The beetles showed a preference for the most humid sites during dry weather. Numbers fell as the hedge was approached and very few occurred under the hedge. Marked beetles were released, and the maximum distance at which they were recovered was 26 yards (23.8 m.). The majority moved in a very restricted area.     

FLORAL BIOLOGY OF MAGNOLIA

The floral biology of eight species of Magnolia native to the United States is described. The flowers are protogynous. They are pollinated by several species of beetles that enter buds as well as closed and open flowers to feed on nectar, stigmas, pollen, and secretions of the petals. Individual flowers persist from two to four days and undergo a series of petal, stigma, and stamen movements that assure pollination by beetles. It is suggested that the flowers of Magnolia are highly specialized for exclusive pollination by beetles. These specialization mechanisms produce large quantities of food for the beetles and deny other types of insects (bees, moths, etc.) access to the flowers at critical stages in the pollination process, i.e., when stigmas are mature and pollen is shed.     

THE EVOLUTION OF AGRICULTURE IN BEETLES (CURCULIONIDAE: SCOLYTINAE AND PLATYPODINAE)

Abstract Beetles in the weevil subfamilies Scolytinae and Platypodinae are unusual in that they burrow as adults inside trees for feeding and oviposition. Some of these beetles are known as ambrosia beetles for their obligate mutualisms with asexual fungi—known as ambrosia fungi—that are derived from plant pathogens in the ascomycete group known as the ophiostomatoid fungi. Other beetles in these subfamilies are known as bark beetles and are associated with free‐living, pathogenic ophiostomatoid fungi that facilitate beetle attack of phloem of trees with resin defenses. Using DNA sequences from six genes, including both copies of the nuclear gene encoding enolase, we performed a molecular phylogenetic study of bark and ambrosia beetles across these two subfamilies to establish the rate and direction of changes in life histories and their consequences for diversification. The ambrosia beetle habits have evolved repeatedly and are unreversed. The subfamily Platypodinae is derived from within the Scolytinae, near the tribe Scolytini. Comparison of the molecular branch lengths of ambrosia beetles and ambrosia fungi reveals a strong correlation, which a fungal molecular clock suggests spans 60 to 21 million years. Bark beetles have shifted from ancestral association with conifers to angiosperms and back again several times. Each shift to angiosperms is associated with elevated diversity, whereas the reverse shifts to conifers are associated with lowered diversity. The unusual habit of adult burrowing likely facilitated the diversification of these beetle‐fungus associations, enabling them to use the biomass‐rich resource that trees represent and set the stage for at least one origin of eusociality.     

取食雄蜂蛹粉对龟纹瓢虫和异色瓢虫卵黄发生的影响

本文比较了龟纹瓢虫Proylea japonica和异色瓢虫Harmonia axyridis取食蚜虫和取食雄蜂蛹粉时的卵黄发生情况。当取食雄蜂蛹粉时,体内卵黄蛋白出现迟,积累速度慢,产卵前期长。但用保幼激素类似物ZR512点滴处理后则能达到与食蚜对照相当的水平。ZR512对取食雄蜂蛹粉瓢虫的作用显著大于取食岈虫者。进一步的研究表明,ZR512能促进这两种瓢虫取食雄蜂蛹粉,但对成虫的体重没有明显的影响。因此推论,雄蜂蛹粉基本能够满足这两种瓢虫生殖的营养需要,但对其内分泌有一定的影响,使瓢虫处于类似生殖滞育的状态。本文根据不同食物条件对卵黄蛋白发生的影响不同,建议用卵黄蛋白的量作为生理指标,以快速初步筛选和评估人工饲料。     

Beetles in the diet of six species of deep‐sea fish

Abstract

Four scarab beetles (Acrossidius tasmaniae) and two unidentified weevils were recovered from the guts of a single individual of six deep‐sea fishes trawled from depths of 326–418 m, c. 30–40 km off the Wairarapa coast, North Island, New Zealand. These constitute the first records of terrestrial arthropods in the diet of deep‐sea fishes from the New Zealand region. Possible reasons describing how these terrestrial beetles came to be eaten by these fishes are discussed.     

REPEATED EVOLUTION OF CROP THEFT IN FUNGUS‐FARMING AMBROSIA BEETLES

Ambrosia beetles, dominant wood degraders in the tropics, create tunnels in dead trees and employ gardens of symbiotic fungi to extract nutrients from wood. Specificity of the beetle–fungus relationship has rarely been examined, and simple vertical transmission of a specific fungal cultivar by each beetle species is often assumed in literature. We report repeated evolution of fungal crop stealing, termed mycocleptism, among ambrosia beetles. The mycocleptic species seek brood galleries of other species, and exploit their established fungal gardens by tunneling through the ambient mycelium‐laden wood. Instead of carrying their own fungal sybmbionts, mycocleptae depend on adopting the fungal assemblages of their host species, as shown by an analysis of fungal DNA from beetle galleries. The evidence for widespread horizontal exchange of fungi between beetles challenges the traditional concept of ambrosia fungi as species‐specific symbionts. Fungus stealing appears to be an evolutionarily successful strategy. It evolved independently in several beetle clades, two of which have radiated, and at least one case was accompanied by a loss of the beetles’ fungus‐transporting organs. We demonstrate this using the first robust phylogeny of one of the world's largest group of ambrosia beetles, Xyleborini.     

BEETLE POLLINATION OF CYCLANTHUS BIPARTITUS (CYCLANTHACEAE)

The morphology, inflorescence phenology, and insect visitors of Cyclanthus were observed during two reproductive seasons at Finca La Selva in the Atlantic lowlands of Costa Rica. The inflorescence of Cyclanthus is an elongate spadix that is subtended and enclosed by four large, cymbiform bracts. Staminate and pistillate flowers are arranged in separate cycles along the length of the spadix and show marked dichogamy. Pollinators of Cyclanthus are beetles of the genus Cyclocephala (Scarabaeidae). The beetles arrive at the inflorescence while it is in the pistillate phase, during the first evening of the 2-day flowering period. They remain in the inflorescence for 24 hrs, until the end of staminate anthesis. The bracts of the inflorescence produce specialized tissue that the beetles consume along with pollen. Chemical analysis of the food tissue indicates that it is almost 50% lipid by dry weight. The scarabs use the inflorescence as an aggregation site for mating. Experiments with bagged inflorescences showed that no seeds are produced in the absence of pollinators, which suggests that Cyclanthus is obligately allogamous.     

Area effect of distribution of Silphids (Coleoptera,Silphidae) on Korean islands

We investigated the spatial patterns in the distribution of carrion beetles on 26 islands to test the area and distance effects on species diversity. The relationships between species richness and assemblage and island area, distance from the mainland, and shortest distance from the largest island within 2?km were analyzed using linear regression, Canonical Correspondence Analysis (CCA) and Multi-Response Permutation Procedures (MRPP). We hypothesized that both area and distance from the mainland played a significant role in species richness, while geographic location in the sea influenced aggregation of carrion beetles on islands. Area was the only factor influencing species richness of carrion beetles on islands. Moreover, distance from the mainland and close islands did not significantly influence to carrion beetles. In addition, geographic location in the same Sea did not influence beetle assemblages. Taken together, the results of this study indicated that carrion beetles on Korean islands were largely affected by island size and that dispersal was stochastic.