桉树枝瘿姬小蜂入侵海南省

桉树枝瘿姬小蜂Leptocybe invasa Fisher ＆ La Salle是一种新入侵的有害生物,专一危害桉属植物。近几年在地中海、非洲、中东和东南亚陆续发生,2007年中国大陆首次发现该虫,2008年7月发现其在海南发生。通过调查,目前在海南省分布在以三亚市、东方市和儋州市为中心的2个圆弧形区域,中心点危害较为严重,植株生长严重受阻。文章介绍桉树枝瘿姬小蜂的鉴别特征、生物学特性、在海南的发现及扩散过程和防控建议。     

桉树枝瘿姬小蜂连续世代种群生命表

桉树枝瘿姬小蜂在广州地区一年发生4-5代,且世代重叠,其越冬期为11月中旬到翌年3月底,越冬虫态为大龄幼虫和蛹.在广州自然条件下,通过人工接种和自然接种相结合的方法,桉树枝瘿姬小蜂在2010年3月至2011年3月间共完成4个世代.利用生命表的方法分析桉树枝瘿姬小蜂连续世代可知,第1代的净增值率R0最大,而第2代的最小;第3代的内禀增长率rm和周限增长率λ最大,其世代平均历期T最小;第4代的rm和λ最小,其T最大.这说明第3代桉树枝瘿姬小蜂的种群增长能力最大,对桉树的危害最强.该代害虫的发生时间为7-9月,因此在防治上要注意该阶段的防控和监测.     

桉树枝瘿姬小蜂产卵行为研究

桉树枝瘿姬小蜂Leptocybe invasa Fisher&La Salle喜好在桉属(Eucalyptus)植物的新生部位产卵。本研究以尾赤桉为寄主研究其产卵模式发现,当天羽化且没有产卵经验的雌成虫在经过寄主识别(116.87 s)和寄主评估(208.27 s)后即进行产卵循环(平均5.87次),每个产卵循环产2粒卵,且搜索行为的发生一般伴随产卵位置的变换。在被观察的15头雌成虫中,平均每头产卵13.60粒,每次产卵持续17.31 s。在产卵过程中,其刺探行为所占总时间的比例和发生频次最大,而静息行为最小。在不同寄主植物间,桉树枝瘿姬小蜂喜好在尾赤桉的叶柄和叶脉处产卵,且2个部位间无显著性差异,而在尾叶桉、巨尾桉、隆缘桉和小果灰桉上,其喜好在叶柄处产卵且显著大于其它2个部位。     

桉树枝瘿姬小蜂成虫感器超微结构

应用扫描电镜对桉树枝瘿姬小蜂Leptocybe invasa Fisher & LaSalle成虫触角、复眼、口器、足以及腹部末端感器的超微结构和分布进行观察。结果表明,在触角上共有8种感器,分别为Bhm氏鬃毛Ⅰ、Bhm氏鬃毛Ⅱ、刺形感器、毛形感器Ⅰ、毛形感器Ⅱ、板形感器Ⅰ、板形感器Ⅱ和钟形感器;口器上有2种感器,分别为毛形感器Ⅳ和刺形感器;在足上有4种感器,分别为毛形感器Ⅰ、毛形感器Ⅲ、刺形感器和锥形感器;在腹部末端也有3种感器,分别为毛形感器Ⅰ、刺形感器和腔形感器。同时还探讨了触角上各种感器的功能。     

五种桉树对桉树枝瘿姬小蜂的抗性研究

本文通过室内网室接虫,以感虫株率、株平均虫瘿数、单株最多虫瘿数和感虫速度4个指标,评价了5种桉树对桉树枝瘿姬小蜂Leptocybe invasa Fisher&La Salle的抗性.结果表明:在人工接种16 d、22 d和25 d后,DH201-2、GL9和邓恩桉分别出现明显的虫瘿,DH32-29和JGI在接种后的40 d内均未出现感虫症状.经方差分析表明,供试的5种桉树对桉树枝瘿姬小蜂的抗性有显著差异,其抗性序列由大到小为:DH32-29=JG1>邓恩桉>GL9>DH201-2.     

桉树枝瘿姬小蜂的耐寒性测定

桉树枝瘿姬小蜂Leptocybe invasa Fisher&LaSalle是一种新入侵的检疫性有害生物,为了明确其对极端低温的耐受性,以了解其适生范围,测定了桉树枝瘿姬小蜂幼虫、蛹、成虫及不同地区、不同寄主条件下雌雄成虫以及广东、广西、海南3省6地越冬幼虫12—3月的过冷却点和冰点。结果表明,不同虫态的过冷却点和冰点由低到高顺序为:蛹<幼虫<成虫。蛹的过冷却点和冰点分别为(-24.93±0.10)℃、(-22.81±0.14)℃,成虫的过冷却点和冰点为(-20.93±0.24)℃和(-17.33±0.27)℃。随着纬度的升高,桉树枝瘿姬小蜂的过冷却点和冰点都呈现降低的趋势。海南地区不同寄主桉树枝瘿姬小蜂过冷却点从低到高的顺序排列为:湛-201<小叶桉<广林9号。在12—3月,桉树枝瘿姬小蜂的越冬幼虫过冷却点和冰点随着环境温度的升高而升高,以广东广州地区1月份的越冬幼虫过冷却点和冰点为最低,其数值分别为(-25.44±0.17)℃和(-24.04±0.21)℃,个体过冷却点的最低值为-26.9℃。由实验结果可知,桉树枝瘿姬小蜂蛹和幼虫的耐寒力最强,以幼虫和蛹越冬。地区、寄主、温度对其耐寒力均有显著的影响,而且其有向现疫区以北的区域扩散的潜能。     

新入侵种桉树枝瘿姬小蜂的危险性评估

采用GARP生态位模型预测分析桉树枝瘿姬小蜂Leptocybeinvasa Fisher&La Salle在中国的潜在地理分布,并参照国际上有害生物危险性定量分析方法,对桉树枝瘿姬小蜂在中国的危险性作出综合评价。结果表明:中国东南部大部分地区都是该虫的适生区,该虫在我国潜在分布区风险评估R值为2.14,存在高度危险性。据此提出针对性的风险管理措施。     

桉树枝瘿姬小蜂在广西博白的研究

桉树枝瘿姬小蜂是严重危害桉属某些品系枝叶的致瘿害虫,自传入当年起在广西博白设点,连续三年对该害虫的形态特征、生活史、寄主、入侵危害、发生规律等生物学特性和防治控制技术进行了研究,本文对该点研究进展作了归纳汇总。     

桉树枝瘿姬小蜂幼虫林间化学防治试验

选用70%吡虫啉水分散粒剂、40%毒死蜱乳油、25%噻虫嗪水分散粒剂以及这3种农药的混配剂,分别稀释成5、10、20倍液,采用注干法对桉树枝瘿姬小蜂幼虫进行林间药效试验。试验表明,施药30 d后,相同浓度的不同药剂对桉树枝瘿姬小蜂幼虫的校正死亡率则存在极显著差异。混配剂5倍液的防治效果最好,在30 d内对桉树枝瘿姬小蜂幼虫的校正死亡率为81.63%。施药后5～10 d,桉树枝瘿姬小蜂幼虫的死亡率增长速度最快;施药10 d后,死亡率的增长速度明显变缓。同一种药剂的浓度越高,对桉树枝瘿姬小蜂幼虫的致死时间越短。     

寄主植物对桉树枝瘿姬小蜂生物学特性的影响

桉树枝瘿姬小蜂Leptocybe invasa Fisher&La Salle是桉属(Eucalyptus)植物的重要枝叶害虫。自2007年在我国发现以来,对广西、海南及广东地区的桉树种植已造成严重危害。本文在野外调查的基础上,研究了海南和广东地区共5种桉树上桉树枝瘿姬小蜂的虫体大小、寿命及怀卵量。结果表明,桉树品种能够显著影响桉树枝瘿姬小蜂的虫体大小;用40%蜂蜜水进行补充营养时,不同寄主植物上桉树枝瘿姬小蜂雌成虫的寿命差异显著,而桉树枝瘿姬小蜂雄虫在不同寄主间无显著性差异;不同寄主植物上桉树枝瘿姬小蜂雌成虫的怀卵量不同,并且随着日龄的延长,其怀卵量呈现上升的趋势。     

桉树枝瘿姬小蜂胚胎发育及胚后发育

【目的】对桉属树木的重要害虫桉树枝瘿姬小蜂Leptocybe invasa胚胎发育及胚后发育生物学特征进行详细调查,以期深入了解该害虫的生物学特征及发生为害规律。【方法】对桉树枝瘿姬小蜂雌性生殖系统、卵、虫瘿进行解剖,观察其胚胎发育和胚后发育过程,测量其各发育阶段的虫瘿、虫室和幼体的体积及薄壁细胞层的厚度。【结果】桉树枝瘿姬小蜂完成胚胎发育约需138 h,由3个阶段组成：产卵后0-24 h为营养物质聚集期;36-84 h为胚胎期;96-138 h为孵化期。桉树枝瘿姬小蜂在虫瘿内完成发育,其发育过程与虫瘿发育过程保持一致。虫瘿结构由3个基本层组成,由外至内分别为表皮层、中间层和薄壁细胞层。桉树枝瘿姬小蜂幼虫体积增长速率随发育时间呈现单峰型,在30 d时增长速率达到最大;虫瘿体积的增长速率呈抛物线状,并且虫瘿内薄壁细胞层厚度随发育时间也呈现抛物线状,其前期增长较快,后期下降变缓。【结论】桉树枝瘿姬小蜂发育至25 d时处于取食量较小的低龄阶段,而虫瘿内薄壁细胞层(食物)厚度已达到最大,为幼虫体积快速增大阶段作好准备。     

寄生美洲大蠊卵鞘的浅沟长尾啮小蜂记述(膜翅目:姬小蜂科)

本文用图文简要记述了从美洲大蠊卵鞘中育出的浅沟长尾啮小蜂Aprostocetus asthenogmus (Waterston)的形态特征.这是该蜂在我国的首次报道,有望今后用于蜚蠊的生物防治.     

Reproductive Biology of <Emphasis Type="Italic">Leptocybe invasa</Emphasis> Fisher &amp; La Salle (Hymenoptera: Eulophidae)

Leptocybe invasa Fisher & La Salle (Hymenoptera: Eulophidae) is an invasive pest in Eucalyptus plantations around the world. The successful colonization of L. invasa is possibly related to its reproductive biology. The objective of this study was to examine the reproductive biology of L. invasa. In Guangxi Province, the sex ratio (proportion of female, 0.99) of L. invasa was female-dominant throughout the year based on natural and artificial infestation. This result was similar to the ratios observed for other geographic populations in China, including those in Fujian (0.99), Guangdong (0.98), Hainan (0.95), Jiangxi (0.96), and Sichuan (0.99). The offspring sex ratio favored females. A large number of females emerged from the galls produced by females, with few males found. Galls on the petioles and midribs of Eucalyptus plants could be caused by newly emerged females with mature eggs. The lengths of the ovariole, spermatheca, common oviduct, and reproductive glands did not differ among L. invasa females, but their lateral oviducts showed differences from 0 to 42 h after emergence, indicating that this insect is proovigenic. These results could explain why L. invasa populations can rapidly increase in invaded areas.     

伴生细菌在入侵种桉树枝瘿姬小蜂克服桉树抗性中的作用

【目的】桉树枝瘿姬小蜂是我国近年来发现的一种主要危害桉属树种的外来有害生物。本研究旨在通过探究中国桉树枝瘿姬小蜂主要伴生细菌在桉树枝瘿姬小蜂成功定殖中的作用。【方法】测定不同抗性品系桉树的次生代谢物质黄酮和单宁的含量以及易感品系桉树在枝瘿姬小蜂危害前后的含量变化。通过体外抑菌和化学物质降解实验,探究桉树枝瘿姬小蜂主要伴生细菌对抗虫性物质黄酮和单宁的耐受性及降解能力。【结果】抗性品系桉树的黄酮和单宁的含量明显高于易感品系,易感品系在桉树枝瘿姬小蜂危害后黄酮和单宁的含量显著提高;高浓度的黄酮和单宁会抑制桉树枝瘿姬小蜂伴生细菌的生长,在中低浓度黄酮和单宁的条件下,主要伴生细菌能够适应,并继续繁殖;桉树枝瘿姬小蜂伴生细菌具有一定的降解黄酮和单宁的能力,其中细菌Staphylococcus cohnii降解黄酮的能力比Pseudomonas geniculate稍强,而Bacillus wiedannii、Serratia macescens对单宁具有较强的降解能力。【结论】桉树枝瘿姬小蜂侵染桉树后,可以诱导桉树产生抗性,桉树产生大量的次生代谢物质来抵御桉树枝瘿姬小蜂的危害,而桉树枝瘿姬小蜂部分伴生细菌可降解桉树次生代谢物质来帮助小蜂克服植物抗性完成定殖。     

Assessment performance of Eucalyptus clones attacked by the recent invasion of Leptocybe invasa (Hymenoptera: Eulophidae): Implications to invasion pest management

Eucalyptus gall wasp, Leptocybe invasa is one of the most important invasive pests of Eucalyptus (Myrtaceae) and has been reported in new cultivation areas worldwide. This pest causes severe damage to susceptible plants of the genus Eucalyptus, where it induces galls in the midribs and petioles of young leaves and the internodes of branch and apices. In this work, we evaluated the response of Eucalyptus clones (E. urophylla (Urophylla) and two clone hybrids, one of the E. urophylla × E. camaldulensis (Urocam) and other of E. urophylla × E. grandis (Urograndis) crossings.) submitted to L. invasa collected from areas where L. invasa was recently reported. Our results show that the eucalypt materials cultivated in the areas where L. invasa were reported sensitive to L. invasa attacks. However, the wasp causes fewer galls in the Urocam clone. Thus, the Urocam clone can be preferred for use to reduce population growth of L. invasa in Brazilian savannah areas.     

Genetic Diversity of the Invasive Gall Wasp Leptocybe invasa (Hymenoptera: Eulophidae) and of its Rickettsia Endosymbiont,and Associated Sex-Ratio Differences

The blue-gum chalcid Leptocybe invasa Fisher & LaSalle (Hymenoptera: Eulophidae) is a gall wasp pest of Eucalyptus species, likely native to Australia. Over the past 15 years it has invaded 39 countries on all continents where eucalypts are grown. The worldwide invasion of the blue gum chalcid was attributed to a single thelytokous morphospecies formally described in 2004. Subsequently, however, males have been recorded in several countries and the sex ratio of field populations has been found to be highly variable in different areas. In order to find an explanation for such sex ratio differences, populations of L. invasa from a broad geographical area were screened for the symbionts currently known as reproductive manipulators, and both wasps and symbionts were genetically characterized using multiple genes. Molecular analyses suggested that L. invasa is in fact a complex of two cryptic species involved in the rapid and efficient spread of the wasp, the first recovered from the Mediterranean region and South America, the latter from China. All screened specimens were infected by endosymbiotic bacteria belonging to the genus Rickettsia. Two closely related Rickettsia strains were found, each infecting one of the two putative cryptic species of L. invasa and associated with different average sex ratios. Rickettsia were found to be localized in the female reproductive tissues and transovarially transmitted, suggesting a possible role of Rickettsia as the causal agent of thelytokous parthenogenesis in L. invasa. Implications for the variation of sex ratio and for the management of L. invasa are discussed.     

First report of Elasmus polistis Burks (Hymenoptera: Eulophidae) recovered from Polistes versicolor (Olivier) (Hymenoptera: Vespidae) nests in Brazil

The first record of Elasmus polistis Burks in Polistes versicolor (Olivier) nests in the Rio Grande do Sul state and in Brazil is provided. A total of 173 specimens of P. versicolor and 790 specimens of E. polistis were collected from two nests from Gramado and Santa Cruz do Sul, RS, Brazil.     

2种不同寄主对桉树枝瘿姬小蜂体内细菌多样性的影响

[目的]桉树枝瘿姬小蜂是一种林业的重要入侵害虫,为了探明桉树枝瘿姬小蜂的寄主适应机制,研究2种不同寄主植物对桉树枝瘿姬小蜂体内细菌群落组成及多样性的影响.[方法]以分别取食巨园桉DH 201-2和窿缘桉的桉树枝瘿姬小蜂雌性成虫为材料,采用Illumina HiSeq高通量测序技术对桉树枝瘿姬小蜂体内细菌16S rDNA...