稻纵卷叶螟的飞行和再迁飞能力

稻纵卷叶螟Cnaphalocrocis medinalis (Guenée)可以通过连续几夜的飞行实现远距离迁移, 这种变幻莫测的再迁飞能力给稻纵卷叶螟的预测造成了极大的困难, 明确其迁飞行为参数是灾变预警的前提。为此, 利用飞行磨装置测定了稻纵卷叶螟成虫的飞行能力和再迁飞能力。结果表明: 在生殖隔离条件下, 稻纵卷叶螟不同日龄和不同性别的成虫的飞行能力间没有显著差异, 雌雄虫的平均飞行时间分别为156.94±103.19 min和147.71±111.38 min。根据吊飞的累计飞行时间(accumulative flight duration, AFD)可将稻纵卷叶螟种群划分为居留型(AFD<40 min)、迁飞型(40 min≤AFD≤130 min)和强迁飞型(AFD>130 min) 3种类型; 且3种类型的个体比率分别为46.1%, 27.3%和26.6%, 其中居留型平均累计飞行时间为11 min, 迁飞型为82 min, 强迁飞型为232 min。稻纵卷叶螟具有很强的再迁飞能力, 其种群作一次迁飞的个体比率都大于90%, 2次(夜)再迁飞的比率达70%以上, 一般可进行4~5次(夜)再迁飞, 最多可达9次(夜)。成虫的补充营养对再迁飞能力没有显著影响, 但蜜水可增强成虫的飞行能力。这些研究结果为稻纵卷叶螟的虫源分析和迁入区预测提供了基本参数。     

温度对米象成虫飞行行为的影响

为探明温度对米象成虫的飞行行为的影响,应用起飞测定装置和昆虫飞行磨对不同温度条件下米象成虫的飞行参数进行了测定。结果显示23℃时,米象即可起飞;23～35℃内,60.0%～73.3%的米象个体具备飞行能力;温度对米象雌成虫的24 h累计飞行距离、24 h累计飞行时间和飞行速度均有显著影响,随温度的升高其飞行能力先增强后减弱,在32℃时上述3个飞行参数均有最大值。米象雄成虫的24 h累计飞行距离、24 h累计飞行时间和飞行速度受温度影响不显著,整体随测定温度的增加呈现先增大后减小的趋势,在29℃时有最大值。米象雌雄成虫的日常日行活动呈现一定的节律性,每日上午和傍晚以后有两个飞行活动高峰。研究结果明确了米象成虫在不同温度条件下的飞行行为特征,可为米象的扩散和害虫感染的预防提供数据支持。     

枣实蝇成虫飞行能力的测定

【目的】为了明确枣实蝇Carpomya vesuviana Costa成虫飞行扩散能力及相关因子对其飞行能力的影响。【方法】本研究以SUN-FL型智能昆虫飞行信息系统（飞行磨）吊飞方法, 测定了不同日龄、性别的枣实蝇成虫的飞行能力, 并探究了温度对枣实蝇飞行能力的影响。【结果】羽化后12 d左右的枣实蝇飞行能力最强, 雌虫平均飞行距离和最远飞行距离分别为1.037和3.192 km, 雄虫分别为0.943和3.085 km; 枣实蝇飞行能力随着日龄的增加呈现先增强后减弱的趋势; 相同日龄的雌成虫平均飞行距离、平均飞行时间略高于雄虫, 雌、雄虫的平均飞行距离、平均最快飞行速度、平均飞行时间之间没有显著性差异; 环境温度28～34℃为枣实蝇最佳飞行温度区间, 且31℃条件下飞行能力最强。【结论】由此可见, 枣实蝇成虫具有较强的迁飞扩散能力。     

取食不同寄主植物的桃小食心虫飞行能力

【目的】评测取食不同寄主植物的桃小食心虫Carposina sasakii飞行能力,为该虫预测预报和防控提供参考。【方法】使用飞行磨装置测定了取食不同寄主植物(海棠、苹果和杏)的桃小食心虫雌雄成虫的飞行能力,比较了取食同一寄主植物的雌雄成虫间和取食不同寄主植物的同一性别个体间平均飞行距离、平均飞行时间、平均飞行速度和最大飞行速度4个飞行参数。【结果】在12 h的飞行测试中,桃食心虫成虫最长飞行距离为24.54 km,最长飞行时间接近12 h,最大飞行速度为5.88 km/h,飞行11~12h的个体占比最高(36.98%)。取食同一寄主的雌成虫各飞行参数值均大于雄成虫。取食苹果和海棠的成虫的平均飞行距离在雌雄间存在显著差异,取食苹果的雌成虫的平均飞行距离显著大于取食杏的个体,取食苹果的雌成虫平均飞行速度和最大飞行速度显著大于取食另外两种寄主的个体;但是取食不同寄主植物的雄成虫间各飞行参数值差异不显著。【结论】桃小食心虫成虫飞行能力较强,取食同一寄主植物的雌雄成虫间以及取食不同寄主植物的雌成虫间飞行能力存在差异。     

温度对花绒寄甲飞行能力的影响

为了了解花绒寄甲的飞行行为以及评估其飞行能力,本研究采用飞行磨吊飞技术,测定了不同性别的花绒寄甲成虫在15℃、20℃、25℃、30℃和35℃条件下的飞行距离、飞行持续时间以及平均飞行速度的差异。研究结果表明,花绒寄甲是一种飞行能力很强的昆虫,24 h内最远能飞行22 km,飞行持续时间可达11 h,飞行平均速度在0.43～0.55 m/s之间。总体上雌性花绒寄甲飞行距离和飞行时间均随温度升高而增加,但温度对飞行速度的影响不显著。生物防治生产实践中,花绒寄甲适宜的释放温度在25℃到35℃之间。     

日龄、性别及线虫侵染对松树蜂飞行能力的影响

【目的】明确松树蜂Sirex noctilio Fabricius雌雄成虫飞行能力随日龄的变化以及线虫Deladenus siricidicola Bedding侵染对松树蜂飞行能力的影响,为研究松树蜂扩散规律及评估线虫防治松树蜂效果提供重要参考资料。【方法】从黑龙江省鹤岗市采集樟子松虫害木,于室内饲养羽化获得松树蜂成虫。利用佳多飞行磨系统对实验种群松树蜂的1、2、3、4、5、6、7、8日龄的雌雄成虫个体分别进行12 h连续吊飞试验,测定其累计飞行距离、累计飞行时间、平均飞行速度。【结果】随日龄增加,松树蜂雌雄成虫在12 h内的累计飞行距离和累计飞行时间呈下降趋势。不同日龄雌成虫的平均飞行速度存在显著差异,随日龄增加,平均飞行速度逐渐下降;不同日龄雄成虫的平均飞行速度无显著差异。不同性别松树蜂飞行能力有差异,雌性相比雄性累计飞行距离和累计飞行时间普遍较高;而不同性别成虫间平均飞行速度未存在显著差异。性别和日龄的互作对松树蜂累计飞行距离的影响达到了显著水平。线虫侵染对雌雄成虫飞行能力(累计飞行距离、累计飞行时间、平均飞行速度)的影响均不显著。【结论】随日龄增加,松树蜂雌雄成虫飞行能力呈下降趋势,雌虫比雄虫的飞行能力较强;线虫侵染对雌雄成虫飞行能力无显著影响。     

黄地老虎飞行能力研究

黄地老虎Agrotis segetum是一种重要的农业迁飞性害虫,研究飞行生物学对明确其迁飞机理有重要意义。本项研究利用昆虫飞行磨系统对黄地老虎的飞行能力进行了测定。对实验室种群飞行能力的测定结果表明:1日龄成虫的飞行能力最弱;3日龄飞行能力最强,其24 h平均飞行时间、平均飞行距离和平均飞行速率分别达到12.16±0.74 h、48.94±3.40 km和3.76±0.12 km/h。雌蛾与雄蛾间的各项飞行参数均无显著差异,但处女成虫平均飞行距离和平均飞行速率均显著高于已交配个体。对渤海湾野外迁飞种群飞行能力的测定显示,早季节北迁个体和晚季节回迁个体的平均飞行时间和平均飞行距离无显著差异,但皆显著低于实验室种群。黄地老虎具有较强的飞行能力,日龄和交配是影响其飞行能力的关键因素。     

温度对甜菜夜蛾飞行能力的影响

温度对甜菜夜蛾飞行能力有显著的影响（P<0.05）。在16～32℃内,成虫均能进行正常的飞行活动。24℃下的成虫飞行能力最强,在15 h的吊飞飞行中,成虫飞行距离最远（37.14 km）、飞行速度最快（0.87 m/s）、飞行时间最长（11.73 h）。温度低于２０℃或高于２８℃时,其飞行能力均显著降低。甜菜夜蛾在不同温度下飞行时对主要能源物质（甘油三酯）的利用效率不同。在较适宜的温度下,尽管成虫飞行消耗的甘油三酯较多,但单位飞行距离所消耗的甘油三酯却较少,即利用效率较高,表明成虫飞行能源物质利用效率的不同是导致其在不同温度下飞行能力产生差异的主要原因之一。     

温湿度对赤拟谷盗成虫飞行能力的影响

本文利用昆虫飞行磨研究了温度和湿度变化对赤拟谷盗Tribolium castaneum(Herbst)雌、雄成虫飞行能力的影响;分别测定了23℃、26℃、29℃、32℃和35℃等5个温度,45%、65%和85%等3个湿度条件下,赤拟谷盗雌、雄成虫的飞行距离、时间和速度等反应昆虫飞行能力的参数。单次飞行距离、单次飞行时间、单次飞行速度、24 h累计飞行距离及时间分析结果表明,环境温度和湿度对赤拟谷盗雌、雄成虫的飞行能力有不同程度的影响,环境温湿度过高或过低均不利于赤拟谷盗雌、雄成虫飞行;温度为32℃时,赤拟谷盗雌成虫的单次飞行距离、飞行时间、飞行速度、24 h累计飞行距离和飞行时间分别为0.925 m、9.616 s、0.023 m/s、0.979 km和2.886 h;雄成虫的单次飞行距离、飞行时间、飞行速度、24 h累计飞行距离和飞行时间分别为0.638 m、6.035 s、0.014 m/s、0.674 km和3.175 h。在相对湿度45%、65%和85%时,雌成虫的单次飞行时间分别为6.998 s、9.616 s和6.431 s;雄成虫的单次飞行时间分别为3.163 s、6.035 s和0.208 s。飞行速度与相对湿度的关系与飞行时间相似。从飞行能力参数来看,雌虫的飞行能力优于雄虫。     

粘虫幼虫密度对成虫飞行与生殖的影响

本文报道了不同幼虫密度下(1、10、20、30、40头/瓶-850m1)粘虫蛾飞行能力与产卵量的变化情况。对未取食1日龄成虫12h飞行能力的测定结果表明,不同幼虫密度羽化的成虫飞行力差异显著(P<0.05),其中以10头/瓶羽化的成虫飞行时间最长(平均225.4分),飞行距离最远(平均17.5km),飞行超过120min的个体为61.1%,超过10 km的为55%。其它处理的各项参数随幼虫密度的增加而下降。粘虫蛾的翅长、翅宽、翅面积和翅负荷随幼虫密度的增加而下降。除翊负荷外,其余各项参数在处理间的差异显著(P<0.05)。成虫飞行能力与蛹重或翅负荷不呈直线相关,但与蛹重具有一定的关系：当蛹重为300-400mg时, 强飞行个体均超过50%, 当小于300mg或大于400mg时,强飞行个体比例下降,当小于225mg时,强飞行个体为零。处理间的成虫产卵量差异显著(P<0.05),且随幼虫密度的增加而下降。密度内的蛹重与成虫产卵量的关系不明显,但密度间的蛹重与产卵量的关系高度相关(r=0.78,P<0.01)。这些结果表明,当粘虫幼虫密度达到一定的阈值时,便可能促使成虫迁飞,而不是等到种群密度很高时才进行迁飞。     

New records of the carabidicolous Laboulbeniales (Ascomycetes) of Japan (II)

Six carabidicolous species of Laboulbeniales are reported as new for the Japanese mycoflora. They areLaboulbenia finitima, L. separata, L. borneensis, L. manubriolata, Dimeromyces caribaeus, andDixomyces ornatus. In Japan, the former three species are parasitic onMochtherus luctuosus and the latter three species onPerigona nigriceps. Laboulbenia finitima occurs on the left legs (tarsi and tibiae);L. separata on the left elytral margin:L. borneensis on the pronotum;L. manubriolata on the pronotum and elytra;Dimeromyces caribaeus on the right inferior posterior surface of the prothorax (pronotal hypomeron); andDixomyces ornatus on the outer margin of the right elytron. Comments and photographs are given for each fungus.     

Ultrastructure of carpospores inGastroclonium clavatum (Roth)Ardissone (Rhodymeniales)

Summary Carpospores ofG. clavatum have been studied under the light and electron microscopes. They are wedge-shaped cells of 80–100 m at their longest diameters. The nucleus is an uncondensed structure provided with a regular outline and a large nucleolus. The plastids constitute heterogeneous populations of organelles differing in size and shape as well as in number and arrangement of the thylakoids. Multiplicating plastids are also present. The mitochondria are small but have well developed cristae. The Golgi apparatus consists of very numerous active dictyosomes. Starch is the main storage substance but some large lipid bodies are also present. Labyrinthine polysaccharide aggregations are present in the carposporial cytoplasm. Multilayered bodies constitute a sui generis very conspicuous cell component.     

Development of Encarsia bimaculata (Heraty and Polaszek) (Hymenoptera: Aphelinidae) in Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) nymphs

Encarsia bimaculata was recently described from India as a potentially useful parasitoid of Bemisia tabaci. Its developmental biology was studied in the laboratory at 25–30 °C and 70–75% RH. Results showed that E. bimaculata is a solitary, arrhenotokous, heteronomous, autoparasitoid. Mated females laid eggs internally in B. tabaci nymphs that developed as primary parasitoids. Males developed as hyperparasitoids, either in females of their own species or in other primary aphelinid parasitoids. Superparasitism was common under cage conditions. Both sexes have an egg, three larval instars, prepupal, and pupal stages. Development from egg to adult took 12.70 ± 2.10 days for females and 14.48 ± 2.60 days for males. Individual B. tabaci nymphs were examined for E. bimaculata parasitization using three isozymes: esterase, malate dehydrogenase, and xanthine dehydrogenase. All three isozymes showed differential banding patterns that identified E. bimaculata parasitized or unparasitized B. tabaci nymphs.     

Recognition of heterospecific parasitism: Competition between Aphidiid (Aphidius ervi) and Aphelinid (Aphelinus asychis) parasitoids of Aphids (Hymenoptera: Aphidiidae; Aphelinidae)

The solitary parasitoids Aphidius erviHaliday (Hymenoptera: Aphidiidae) and Aphelinus asychisWalker (Hymenoptera: Aphelinidae) attacked but generally did not oviposit in pea aphids parasitized by the other species. Wasps selectively oviposited in unparasitized hosts when given a choice. Host discrimination depended on the recognition of internal cues. Females of A. asychiseither could not recognize or ignored A. ervi'sexternal host marking pheromone. Under most conditions, A. ervisurvived in superparasitized hosts, killing competing A. asychislarvae by physical attack and possibly physiological suppression. The outcome of larval competition was not affected by oviposition sequence or age difference between larvae; A. asychissurvived only when it had substantially completed larval development before the host was superparasitized by A. ervi.It is suggested that competition for host resources incurs a cost, for the winner in terms of reduced size or increased development time and for the loser in terms of lost progeny and searching time. Consequently, heterospecific host discrimination can be functional. Internal, and probably general, cues enable wasps to recognize and avoid oviposition in hosts already parasitized by an unrelated species.     

Heterostyly in species ofNarcissus (Amaryllidaceae) andHugonia (Linaceae) and other disputed cases

The hypothesis ofHenriques andFernandes that several Iberian species ofNarcissus (Amaryllidaceae) are tristylous is reconsidered. Contrary to the opinion ofBateman and most subsequent authors, we believe that the available evidence indicates that some populations ofN. triandrus andN. fernandesii, at least, are tristylous; other populations ofN. triandrus are distylous.Hugonia cf.penicillanthemum (Linaceae) from new Caledonia is distylous, but it remains possible that other species ofHugonia are tristylous. The disputed occurrence of heterostyly in S. African species ofBauhinia (Leguminosae),Cleome (Capparaceae) andAneilema (Commelinaceae), and inAgelaea (Connaraceae) is discussed.     

Low levels of allozyme differentiation betweenPyxidanthera (pyxie-moss) taxa (Diapensiaceae)

TwoPyxidanthera morphs of questionable taxonomic rank are described in the eastern United States. We analyzed leaf samples from ninePyxidanthera populations (four of each morph and one with intermediate morphology) for 13 allozyme loci. Our results do not support differentiation of the two morphs at the species level. Mean genetic identity among populations was high ( = 0.97), and typical of that found for conspecific populations. The proportion of total genetic diversity found among populations was low (G_ST = 0.079). Several low frequency alleles were confined to each of the morphs, being found in some of the populations of each morph, but not all.     

Generic delimitation of Aralia (Araliaceae)

Aralia, described by Linnaeus, remains a poorly defined genus. Many satellite genera ofAralia have been proposed, and some have been accepted without critical evaluation. These genera includeCoudenbergia, Megalopanax, Parapentapanax, andPentapanax. This study examined the historical background of the establishment of these genera and their diagnostic characters. It was found that (1)Aralia s. str. is a relatively diverse genus; (2) the separation ofPentapanax andParapentapanax fromAralia is unsubstantiated; (3)Megalopanax is synonymous withCoudenbergia; and (4) the boundaries betweenAralia and bothCoudenbergia andPentapanax intergrade. It is proposed, therefore, to mergeCoudenbergia, Parapentapanax, andPentapanax withAralia, which has nomenclatural priority.Aralia is herein defined as consisting of those species in Araliaceae with pinnate leaves, articulated rachises, five to eight-merous flowers, petals imbricate in buds, and articulated pedicels. The revised generic concept requires the following new combinations or new names:Aralia castanopsisicola, A. franchetti, A. gigantea, A. laevis, A. leschenaultii, A. parasitica, A. rex, A. subcordata, A. verticillata, andA. warmingiana.     

Infection of Glaucocystis nostochinearum (Glaucophyta) by Lagenidium sp. (Oomycota) and its hyperparasite Pythiella sp. (Oomycota)

The glaucophyte Glaucocystis nostochinearum has to our knowledge been observed to be infected by a parasite for the first time. It was found in samples taken from the northernmost freshwater pond in Germany (on the island of Sylt). The fungal parasite was identified as the oomycete Lagenidium sp. which itself was parasitised by another oomycete, Pythiella sp.     

The Bionomics ofCoptera Haywardi(Ogloblin) (Hymenoptera: Diapriidae) and Other Pupal Parasitoids of Tephritid Fruit Flies (Diptera)

The endoparasitoidCoptera haywardi(Ogloblin) (Diapriidae) was discovered in Mexico attacking the pupae of the Mexican fruit fly,Anastrepha ludens(Loew). Typically, parasitoids of Diptera Cychlorrhapha pupae develop as ectoparasitoids and are generalists that attack hosts in a number of families. Aspects of the bionomics ofC. haywardiwere compared to those of two chalcidoid ectoparasitoids,Dirhinus himalayanusWestwood andSpalangia geminaBoucek.C. haywardideveloped in three genera of Tephritidae, but not in species of other families. The two species of chalcidoids developed in all the calypterate and acalypterate hosts to which they were exposed. In an olfactometerC. haywardipreferredAnastrepha suspensa(Loew) pupae, while the chalcidoids preferred the pupae ofMusca domestica L.This preference inS. geminawas diminished in insects that had been reared onA. suspensa. C. haywardioviposited in theA. suspensapupae that had been previously parasitized by the braconidDiachasmimorpha longicaudata(Ashmead). However, it completed development only in unparasitized pupae. Mortality of the primary parasitoid due toD. himalayanuswas approximately two-thirds the mortality inflicted on the host fly.S. geminadid not discriminate between parasitized and unparasitized pupae ofA. suspensaand developed in both.C. haywardiappears to have a more restricted host range relative to chalcidoid pupal parasitoids and this may be due to its endoparasitic development.     

Establishment and spread of two introduced parasitoids (Ichneumonidae) of the birch leafminer, Fenusa pusilla (Lepeletier) (Tenthredinidae)

Lathrolestes nigricollis(Thomson) and Grypocentrus albipes Ruthe,Palearctic specialist parasitoids of thebirch-leafmining sawfly Fenusa pusilla(Lepeletier), were imported from central Europe andreleased at three locations in Edmonton, Alberta,Canada during 1994–1996. Parasitoids becameestablished at two locations, L. nigricollis atboth and G. albipes at one, and were recoveredfor 3–5 years after release. Lathrolestesnigricollis has dispersed throughout most ofEdmonton, and at least 13 km from release sites, butG. albipes has been recovered only 400–500 mfrom one release site. Five years after introductionat one site, percent parasitism by L.nigricollis was 78% and 84% for the first andsecond generations, respectively, and about 48% ofparasitoid eggs were encapsulated.