寄主对蝇蛹俑小蜂发育及寄生效能的影响

【背景】蝇蛹俑小蜂是蝇类害虫蛹期重要的寄生蜂,该蜂可寄生家蝇、瓜实蝇、橘小实蝇和南瓜实蝇等多种蝇类害虫。研究蝇蛹俑小蜂对寄主的选择性及在不同寄主上的发育情况有助于该寄生蜂的扩繁和利用。【方法】在温度(26±1)℃、相对湿度(70±5)%,光周期L∶D=14 h∶10 h的条件下,研究了蝇蛹俑小蜂对瓜实蝇蛹、南瓜实蝇蛹和橘小实蝇蛹的寄生率及子代蜂发育、寿命的影响。【结果】蝇蛹俑小蜂在瓜实蝇蛹、橘小实蝇蛹和南瓜实蝇蛹上均能产卵并发育至成虫,其对瓜实蝇蛹的选择系数和寄生率分别为0.37和55.33%,显著高于其对另外2种实蝇蛹。在非选择条件下,蝇蛹俑小蜂在瓜实蝇蛹上的出蜂量最高,发育历期最短。在同一寄主条件下,蝇蛹俑小蜂雌蜂的发育历期、寿命显著较雄蜂的长,雌蜂的质量显著大于雄蜂。【结论与意义】蝇蛹俑小蜂可用于瓜实蝇的防治,瓜实蝇蛹是扩繁蝇蛹俑小蜂的理想寄主。     

蝇蛹俑小蜂对橘小实蝇和瓜实蝇的偏好性

【背景】蝇蛹俑小蜂是实蝇类害虫蛹期的一种重要寄生蜂,对压制下一代实蝇类害虫的种群数量具有重要作用,但有关其对不同实蝇害虫的寄生特性尚缺乏研究。【方法】采用"H"型装置和培养皿测定方法,研究了蝇蛹俑小蜂的寄主选择偏好性。【结果】蝇蛹俑小蜂在橘小实蝇蛹和瓜实蝇蛹共存的情况下,偏好在橘小实蝇蛹上停留,且寄生率较高,最高寄生率达61.11%。【结论与意义】本研究为合理利用蝇蛹俑小蜂控制实蝇类害虫提供了理论基础。     

多寄主型寄生蜂蝇蛹俑小蜂对新寄主的选择与适应性

【目的】明确多寄主型寄生蜂蝇蛹俑小蜂Spalangia endius对不同类型新寄主的偏好选择与适应性。【方法】选择分别以瓜实蝇Zeugodacus cucurbitae、南瓜实蝇Z.tau和家蝇Musca domestica的蛹为寄主饲养的蝇蛹俑小蜂成蜂,比较研究其对上述3种寄主中其他2种非饲养寄主的选择行为、寄生选择及适应性。【结果】与家蝇蛹相比,以瓜实蝇蛹为饲养寄主的蝇蛹俑小蜂成蜂偏好选择和寄生南瓜实蝇蛹,且在南瓜实蝇蛹上产生更多的子代;以南瓜实蝇蛹为饲养寄主的蝇蛹俑小蜂成蜂偏好选择和寄生瓜实蝇蛹,且在瓜实蝇蛹上产生更多的子代;而以家蝇蛹为饲养寄主的蝇蛹俑小蜂成蜂对瓜实蝇蛹和南瓜实蝇蛹的选择数量以及在选择和非选择试验条件下的寄生率与子代数量上并无显著差异。此外,以瓜实蝇和南瓜实蝇蛹为饲养寄主的蝇蛹俑小蜂成蜂分别更容易适应南瓜实蝇和瓜实蝇蛹。【结论】基于3种蝇的生态位关系,推测蝇蛹俑小蜂偏好选择和更容易适应与其饲养寄主有重叠生态位的新寄主。     

蝇蛹俑小蜂对寄主及果实的趋性反应

【背景】蝇蛹俑小蜂是实蝇类害虫蛹期重要的寄生蜂之一。有关植物果实和寄主挥发物在蝇蛹俑小蜂寻找寄主过程中的作用尚不明确。【方法】采用"Y"型嗅觉仪测试了寄主和果实(健康果实和虫害诱导果实)对蝇蛹俑小蜂的引诱作用。【结果】虫伤1 d的番石榴和杨桃果实对蝇蛹佣小蜂雌蜂具有显著的引诱作用;寄主蛹——3日龄橘小实蝇蛹和4日龄瓜实蝇蛹对蝇蛹俑小蜂雌蜂也具有显著的引诱作用。蝇蛹俑小蜂雌蜂对雄蜂有显著的吸引作用。橘小实蝇性诱剂甲基丁香酚对蝇蛹俑小蜂的搜索行为则无显著影响。【结论与意义】寄主蛹和幼虫危害1 d的果实能释放对蝇蛹俑小蜂有引诱作用的物质,这可为利用蝇蛹俑小蜂防治实蝇类害虫提供基础信息。     

寄主大小对蝇蛹俑小蜂Spalangia endius(Walker)产卵选择和发育的影响

【背景】对寄生蜂与寄主之间关系的研究是寄生蜂有效利用的基础。寄生蜂雌蜂通常选择最适于子代蜂发育的寄主进行产卵。【方法】在室内26℃条件下,研究了橘小实蝇蛹体型大小对蝇蛹俑小蜂产卵和生长发育的影响。采用饥饿方法处理3龄橘小实蝇幼虫以获得体型大小(用体质量表示)差异较大的寄主蛹,供寄生蜂选择寄生。【结果】蝇蛹俑小蜂显著偏好寄生体型中等的寄主蛹,然而,随着寄主体型的增大,后代雌性比率增大,且寄主蛹个体大小与后代雌蜂体型大小存在显著的正相关;橘小实蝇蛹个体大小对蝇蛹俑小蜂后代发育历期和寿命无显著影响。【结论与意义】蝇蛹俑小蜂雌蜂能够根据寄主蛹质量来调整后代数量和性比,以使后代适应度最大化。     

不同日龄南瓜实蝇蛹对蝇蛹俑小蜂寄生选择、发育及寿命的影响

蝇蛹俑小蜂Spalangia endius(Walker)是实蝇类害虫的蛹期单寄生蜂。本文在温度26℃±1℃、相对湿度(RH)为70%±5%、光周期L∶D=14 h∶10 h的条件下,研究了不同日龄南瓜实蝇蛹对蝇蛹俑小蜂选择、发育及寿命的影响。结果表明:在选择性和非选择性试验中,蝇蛹俑小蜂均偏好寄生3、4日龄的南瓜实蝇蛹,且随着南瓜实蝇蛹龄期的增加,蝇蛹俑小蜂对其寄生率呈下降趋势。蝇蛹俑小蜂能在1-7日龄南瓜实蝇蛹上产卵并可发育至成虫,在3、4日龄的南瓜实蝇蛹上的发育历期显著较短,子代雌蜂寿命较长。综上所述,3、4日龄的南瓜实蝇蛹是蝇蛹俑小蜂寄生的最佳时期。     

长柄俑小蜂寄生橘小实蝇蛹的功能反应

长柄俑小蜂寄生橘小实蝇蛹的功能反应符合功能反应模型HollingⅡ型,其方程为:Na=1.5324TrN0/(1 1.5324ThN0)。每只寄生蜂在24 h内最大寄生量为17.57只橘小实蝇蛹。寄生1只寄主蛹所需的时间为1.37 h;瞬时攻击率(功能系数)为0.6526;长柄俑小蜂自身密度对寄生产生干扰效应,用Hassell-Varley模型可表示为:α=0.1085P-0.1929。     

瓜实蝇2种蛹寄生蜂生防潜能比较

[目的] 比较研究蝇蛹俑小蜂与蝇蛹金小蜂对瓜实蝇的控制潜能。[方法] 采用非选择性实验测定蝇蛹俑小蜂与蝇蛹金小蜂对瓜实蝇蛹的寄生效能、繁殖能力,并研究覆土厚度对2种寄生蜂寄生效能的影响。[结果] 2种寄生蜂对瓜实蝇的寄生率无显著性差异,但蝇蛹金小蜂的平均单雌产后代数比蝇蛹俑小蜂的多,分别为30和23头。土壤厚度显著影响2种寄生蜂的寄生效能,随着土壤厚度的增加,2种寄生蜂对瓜实蝇蛹的寄生率均显著下降,但蝇蛹金小蜂的寄生率下降更为迅速;蝇蛹俑小蜂最深可寄生8 cm土壤下的瓜实蝇蛹,而蝇蛹金小蜂在土壤厚度达到3 cm时就不能完成寄生。[结论] 蝇蛹俑小蜂较蝇蛹金小蜂更适合应用于瓜实蝇蛹的生物防治。     

以冷冻和新鲜家蝇蛹为寄主的蝇蛹俑小蜂实验种群生命表参数比较

【目的】为了阐明以冷冻保存家蝇Musca domestica蛹为寄主对繁殖蝇蛹俑小蜂Spalangia endius的影响。【方法】本研究分别利用新鲜和-20℃冷冻保存的家蝇蛹为寄主,记录了小蜂日存活数、日后代数量和性别等,并分别构建了实验种群生命表,分析比较了两种类型家蝇蛹对小蜂寄生率、日后代数量和性比、生命表参数等的影响。【结果】与新鲜家蝇蛹为寄主时相比,小蜂在以冷冻蛹为寄主时寄生率、后代数量和雄性百分比均较低（P<0.01）,成蜂寿命和产卵期差异不大（P>0.05）。在以新鲜和冷冻家蝇蛹为寄主时,小蜂寄生率和后代数量均随日龄的增加而显著降低（P<0.01）;以新鲜和冷冻家蝇蛹为寄主时小蜂的净生殖率（R₀）分别为34.91和20.16,种群内禀增长率（r_m）分别为0.17和0.11,均以寄生新鲜家蝇蛹时较大（P<0.01）;在以冷冻家蝇蛹为寄主时,世代时间和种群倍增时间较以新鲜家蝇蛹为寄主时有所延长（P<0.01）。【结论】蝇蛹俑小蜂可以利用冷冻家蝇蛹为寄主完成生活史;在规模化繁殖蝇蛹俑小蜂时,使用冷冻方式保存家蝇蛹的方法具有重要价值。     

家蝇蛹和果蝇蛹繁育的蝇蛹金小蜂对果蝇蛹的寄生比较

【目的】蝇蛹金小蜂Pachycrepoideus vindemmiae(Rondani)是杨梅园等果园果蝇类害虫蛹期常见寄生蜂种类,在对果蝇类害虫的生物防治上具有重要价值。本文旨在探讨使用家蝇蝇蛹为替代寄主繁育蝇蛹金小蜂的方法。【方法】探讨分别以家蝇蛹和果蝇蛹繁育的蝇蛹金小蜂对家蝇和果蝇蝇蛹的选择性,并比较了在两种寄主上繁育的蝇蛹金小蜂在大小、寿命、产卵期、后代产量和性比等方面的差异。【结果】结果表明与果蝇蛹相比,家蝇蛹明显较大,在家蝇蛹上发育的蝇蛹金小蜂后代个体也明显较大;家蝇蛹和果蝇蛹发育的寄生蜂雌蜂寿命为(13.4±4.11)和(3.94±2.49)d、产卵期分别为(11.4±4.11)和(3.13±2.42)d、单头雌蜂后代雌蜂数量分别为(34.31±31.83)和(7.88±3.58)头,在家蝇蛹上繁育的寄生蜂明显具有较长的寿命和产卵期、更多的雌雄蜂后代数量;在对家蝇蛹和果蝇蛹的选择上,繁育自家蝇和果蝇的蝇蛹金小蜂雌蜂选择频率的差异不大。【结论】利用家蝇蛹繁殖的蝇蛹金小蜂在寄生果蝇蛹时具有更大优势,在繁殖蝇蛹金小蜂控制杨梅园等果蝇的为害时,可以选择家蝇蛹作为替代寄主。     

Molecular and morphological characterization of Leveillula (Ascomycota: Erysiphales) on monocotyledonous plants

Leveillula on monocotyledonous plants have been recorded as L. taurica by several authors, whereas the fungus on Allium has been described as an independent species, namely L. allii, by some authors. We sequenced ca 600 bp of the rDNA ITS region for two Leveillula specimens from Allium and Polianthes (both from monocotyledons) and compared them with several already published sequences from Leveillula isolates from dicotyledons. Pair-wise percentages of sequence divergences were calculated for all Leveillula isolates. The ITS sequence of the Polianthes isolate was identical to L. taurica on Helianthus and Vicia. The sequence of the Allium isolate was 99.5 % identical to L. taurica on Euphorbia, Haplophylum, Peganum, etc. These results suggest close relationships between monocot and dicot pathogenic Leveillula species. The identity between two monocot isolates was 98.4 %. Phylogenetic analysis revealed that the two monocot isolates do not group into a clade together. This result suggests that Leveillula acquired parasitism to monocots at least twice independently.     

Foreign exploration for Scirtothrips perseae Nakahara (Thysanoptera: Thripidae) and associated natural enemies on avocado (Persea americana Miller)

Scirtothrips perseae Nakahara was discovered attacking avocados in California, USA, in 1996. Host plant surveys in California indicated that S. perseae has a highly restricted host range with larvae being found only on avocados, while adults were collected from 11 different plant species. As part of a management program for this pest, a “classical” biological control program was initiated and foreign exploration was conducted to delineate the home range of S. perseae, to survey for associated natural enemies and inventory other species of phytophagous thrips on avocados grown in Mexico, Guatemala, Costa Rica, the Dominican Republic, Trinidad, and Brazil. Foreign exploration efforts indicate that S. perseae occurs on avocados grown at high altitudes (>1500 m) from Uruapan in Mexico south to areas around Guatemala City in Guatemala. In Costa Rica, S. perseae is replaced by an undescribed congener as the dominant phytophagous thrips on avocados grown at high altitudes (>1300 m). No species of Scirtothrips were found on avocados in the Dominican Republic, Trinidad, or Brazil. In total, 2136 phytophagous thrips were collected and identified, representing over 47 identified species from at least 19 genera. The significance of these species records is discussed. Of collected material 4% were potential thrips biological control agents. Natural enemies were dominated by six genera of predatory thrips (Aeolothrips, Aleurodothrips, Franklinothrips, Leptothrips, Scolothrips, and Karnyothrips). One genus each of parasitoid (Ceranisus) and predatory mite (Balaustium) were found. Based on the results of our sampling techniques, prospects for the importation of thrips natural enemies for use in a “classical” biological control program in California against S. perseae are not promising.     

Molecular phylogeny of the Acre clade (Crassulaceae): Dealing with the lack of definitions for Echeveria and Sedum

The phylogenetic relationships within many clades of the Crassulaceae are still uncertain, therefore in this study attention was focused on the “Acre clade”, a group comprised of approximately 526 species in eight genera that include many Asian and Mediterranean species of Sedum and the majority of the American genera (Echeveria, Graptopetalum, Lenophyllum, Pachyphytum, Villadia, and Thompsonella). Parsimony and Bayesian analyses were conducted with 133 species based on nuclear (ETS, ITS) and chloroplast DNA regions (rpS16, matK). Our analyses retrieved four major clades within the Acre clade. Two of these were in a grade and corresponded to Asian species of Sedum, the rest corresponded to a European–Macaronesian group and to an American group. The American group included all taxa that were formerly placed in the Echeverioideae and the majority of the American Sedoideae. Our analyses support the monophyly of three genera – Lenophyllum, Thompsonella, and Pachyphytum; however, the relationships among Echeveria, Sedum and the various segregates of Sedum are largely unresolved. Our analyses represents the first broad phylogenetic framework for Acre clade, but further studies are necessary on the groups poorly represented here, such as the European and Asian species of Sedum and the Central and South American species of Echeveria.     

Suitability of Aphis fabae, Myzus persicae (Homoptera: Aphididae) and Aleyrodes proletella (Homoptera: Aleyrodidae) as prey for Coccinella undecimpunctata (Coleoptera: Coccinellidae)

The suitability of Aphis fabae Scopoli, Myzus persicae Sulzer and Aleyrodes proletella L. as food sources for Coccinella undecimpunctata L. was evaluated by studying the impact of prey consumption on the predator’s population growth parameters and feeding parameters. Unlike A. proletella, A. fabae and M. persicae supported the development and reproduction of C. undecimpunctata. A. fabae and M. persicae were considered to be essential prey, whereas A. proletella was considered to be an alternative prey. Aphid species showed different degrees of suitability: M. persicae significantly decreased the pre-oviposition period and increased adult longevity, fecundity and fertility compared with A. fabae. Moreover, A. fabae represents a suitable diet for larval development, but is not a suitable food source for adult reproduction. The predator’s population growth parameters, R₀, r_m and λ were increased with M. persicae, whereas T decreased. We found that the 4th instar larvae were the most voracious, particularly when fed on M. persicae; nevertheless, with this prey daily weight gain and feeding efficiency of 4th instar larvae were similar to that of individuals fed with A. fabae.     

The phylogenetic placement of Ostropales within Lecanoromycetes (Ascomycota) revisited

Results of molecular studies regarding the phylogenetic placement of the order Ostropales and related taxa within Lecanoromycetes were thus far inconclusive. Some analyses placed the order as sister to the rest of Lecanoromycetes, while others inferred a position nested within Lecanoromycetes. We assembled a data set of 101 species including sequences from nuLSU rDNA, mtSSU rDNA, and the nuclear protein-coding RPB1 for each species to examine the cause of incongruencies in previously published phylogenies. MP, minimum evolution, and Bayesian analyses were performed using the combined three-region data set and the single-gene data sets. The position of Ostropales nested in Lecanoromycetes is confirmed in all single-gene and concatenated analyses, and a placement as sister to the rest of Lecanoromycetes is significantly rejected using two independent methods of alternative topology testing. Acarosporales and related taxa (Acarosporaceae group) are basal in Lecanoromycetes. However, if the these basal taxa are excluded from the analyses, Ostropales appear to be sister to the rest of Lecanoromycetes, suggesting different ingroup rooting as the cause for deviating topologies in previously published phylogenies.     

Insecticidal action of Bauhinia monandra leaf lectin (BmoLL) against Anagasta kuehniella (Lepidoptera: Pyralidae), Zabrotes subfasciatus and Callosobruchus maculatus (Coleoptera: Bruchidae)

Bruchid beetle larvae cause major losses in grain legume crops throughout the world. Some bruchid species, such as the cowpea weevil (Callosobruchus maculatus) and the Mexican bean weevil (Zabrotes subfasciatus), are pests that damage stored seeds. The Mediterranean flour moth (Anagasta kuehniella) is of major economic importance as a flour and grain feeder; it is often a severe pest in flour mills. Plant lectins have been implicated as antibiosis factors against insects. Bauhinia monandra leaf lectin (BmoLL) was tested for anti-insect activity against C. maculatus, Z. subfasciatus and A. kuehniella larvae. BmoLL produced ca. 50% mortality to Z. subfaciatus and C. maculatus when incorporated into an artificial diet at a level of 0.5% and 0.3% (w/w), respectively. BmooLL up to 1% did not significantly decrease the survival of A. kuehniella larvae, but produced a decrease of 40% in weight. Affinity chromatography showed that BmoLL bound to midgut proteins of the insect C. maculatus. 33 kDa subunit BmoLL was not digested by midgut preparations of these bruchids. BmoLL-fed C. maculatus larvae increased the digestion of potato starch by 25% compared with the control. The transformation of the genes coding for this lectin could be useful in the development of insect resistance in important agricultural crops.     

Functional response of Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) to Aphis gossypii Glover (Homoptera: Aphididae) in the Laboratory

Stage specific functional response of Harmonia axyridis (Pallas) to varying densities of Aphis gossypii Glover was examined in a simplified cucumber leaf arena under laboratory conditions. All stages of H. axyridis were isolated individually for 24 h with different prey densities at 25 °C and a photoperiod of 16:8 (L:D) h. The number of prey consumed by the predator was checked at 3, 6, 12, and 24 h. All stages of H. axyridis showed a Type II functional response. Based on the random predator equation, estimated attack rates of H. axyridis at 24 h were 0.0037, 0.0442, 0.3590, 0.3228, and 0.1456, and estimated handling times were 4.1001, 2.4575, 0.7500, 0.2132, and 0.1708 h for the first, second, third, and fourth instars, and female adult, respectively.     

Molecular phylogeny of the genus Stereocaulon (Stereocaulaceae, lichenized ascomycetes)

In the present study phylogenetic relationships of the genus Stereocaulon (lichenized ascomycetes) were examined using DNA sequences from the ITS1–5.8 S–ITS2 rDNA gene cluster and from the protein-coding β-tubulin gene. In addition to the fruticose species traditionally classified in Stereocaulon, representatives of the crustose species that have recently been transferred to the genus were included. Muhria, a monotypic genus that is morphologically similar to Stereocaulon, differing only in apothecia ontogeny, was also incorporated. The analyses included 101 specimens from the ingroup representing 49 taxa. Sequences from both DNA regions were analysed simultaneously using direct optimization under the parsimony optimality criterion. The results support the inclusion of the crustose species and Muhria in Stereocaulon, while the current infrageneric classification is not supported. As Muhria is securely nested within Stereocaulon the new combination Stereocaulon urceolatum comb. nov. (syn. Muhria urceolata) is made. Further, species concepts need to be re-examined, as some species do not appear as monophyletic entities in the phylogeny.     

国产尖叶蛇根草(茜草科)的订正

中国文献中记载的尖叶蛇根草（Ophiorrhiza hispida Hook.f.）以及采自中国鉴定为该种的标本均实为近簇花蛇根草（O.pseudofasciculata Schanzer）,在此予以纠正。     

Molecular phylogeny supports a Northern Hemisphere origin of Golovinomyces (Ascomycota: Erysiphales)

Golovinomyces is a strictly herb-parasitic genus in the Erysiphaceae. Host–parasite co-speciation was reported recently between the genus Golovinomyces and Asteraceae from molecular phylogenetic analyses. The Asteraceae originated in South America and latterly expanded their geographic distribution into the Northern Hemisphere. If the co-speciation between Golovinomyces and Asteraceae originated in South America, the geographic origin of Golovinomyces could be assumed to be South America. To address this question, Golovinomyces species from hosts of the tribe Mutisieae, an asteraceous tribe endemic to South America, were collected and the ITS and 28S rDNA regions sequenced. Results indicate that Oidium mutisiae and Golovinomyces leuceriae isolated from the Mutisieae do not belong at the base of the Golovinomyces tree. Instead, they are situated separately within two different clades of Golovinomyces isolates from the Northern Hemisphere. Therefore, the tribe Mutisieae is not the most early host of Golovinomyces. Present results suggest that Golovinomyces originated in the Northern Hemisphere, and not in South America. The new species Oidium reginae for the previous O. mutisiae on Mutisia decurrens is proposed.