温度对食菌小蠹光滑足距小蠹实验种群发育和繁殖的影响

为了明确温度对光滑足距小蠹Xylosandrus germanus发育和繁殖的影响, 本研究分别采用真菌Acremonium kiliense和Ambrosiella hartigii在培养皿中饲养雌成虫和幼虫, 以及半人工饲料在试管中培养雌成虫的方法, 系统地研究了该食菌小蠹在16~31℃范围内6个恒温条件下的发育和16~28℃范围内5个恒温条件下的繁殖力和性比。结果表明: 从16~28℃, 光滑足距小蠹未成熟期各虫态和卵至成虫的发育历期均随温度升高而缩短, 16℃时蠹虫的发育历期为28℃时的3~4倍, 31℃时除蛹外发育历期又有延长。各温度下均以幼虫的发育历期为最长, 占卵至成虫羽化整个发育历期的50%以上。幼虫发育的最适温度为26.44℃。发育起点温度在11.0℃（蛹）至12.7℃（卵至成虫）之间。卵期有效积温最小（61.5日·度）, 幼虫期最大（189.7日·度）, 卵至成虫需要12.7℃以上约305日·度的积温才能完成发育。卵至成虫的存活率在16~25℃范围内从53.3%增大至68.3%, 28~31℃范围内又从35.0%降至3.3%。31℃时幼虫几乎不能化蛹。在半人工饲料中, 22~25℃范围内每雌平均后代数为114.3~121.5头, 以25℃时为最大, 约为16℃时的3倍、19℃和28℃时的2倍。雌雄性比以16℃时为最小（9.6∶1）, 25℃时最大（23.3∶1）, 其余温度下均为19.0∶1以上。结果说明, 温度直接影响光滑足距小蠹的发育, 主要通过影响虫道真菌生长和产孢而影响光滑足距小蠹的繁殖。     

葡萄树新害虫——光滑足距小蠹的形态特征

采用扫描电镜技术研究成都市农泉驿区危害葡萄的小蠹——光滑足距小蠹Xylosandrus germanus(Blandford)的形态特征。该小蠹具有明显的性二型现象。成虫光亮。雌成虫圆柱形,体长2.02～2.26mm,雄成虫较宽扁,体长1.00～1.30mm。在扫描电镜下,可见成虫前胸前缘的刻点毛均从基部分成两叉,但雌成虫略呈锯齿状,雄成虫呈栉齿状。雌成虫具有贮菌器,位于前胸背板的后端下面。雌成虫鞘翅分为沟中和沟间部,后半部细长毛起自沟间部,雄成虫鞘翅不分沟中和沟间部,后半部部分刻点生有细长毛。     

雅尺蛾属研究及其生物地理学特征讨论（鳞翅目：尺蛾科）

雅尺蛾属 Apocolotois 1936年由Wehrli定名,属古北界分布,世界共记录3种：斑雅尺蛾A. arnoldiaria, 二白点雅尺蛾A. smirnovi, 短瓣雅尺蛾A. almatensis。本文记述了所有种类,其中A. almatensis 为中国新记录种;修订了国内部分研究,双珠雅尺蛾Chariaspilates shuangzhu Yang被确定为二白点雅尺蛾A. smirnovi的新异名;重新归纳了属的特征并编制了分种检索表;附所有种类的成虫及♂外生殖器图。所见标本均为雄性,猜测雌蛾可能无翅。对该属及所含物种的动物地理特征进行了初步分析。     

黑龙江省长白落叶松八齿小蠹虫体及坑道的真菌类群

采集落叶松八齿小蠹成虫、幼虫、蛹,以及母坑道、子坑道、蛹室的韧皮组织和蓝变组织。采用马丁氏培养基和PDA综合培养基对各虫态体表、体内、坑道内真菌进行分离培养,统计真菌检出率。对获得的真菌菌株通过形态学和分子生物学相结合的方法进行鉴定。在落叶松八齿小蠹虫体内外和坑道内共分离出真菌24种,其中子囊菌7种,担子菌2种,无性型真菌15种。从各虫态体表共分离出真菌21种,从体内共分离出真菌6种,24种真菌在坑道内均有检出。其中,Ceratocystis fujiensis为检出率较高的蓝变真菌。     

落叶松八齿小蠹体内外和坑道内真菌类群

采集落叶松八齿小蠹成虫、幼虫、蛹,以及母坑道、子坑道、蛹室的韧皮组织和蓝变组织。采用马丁氏培养基和PDA综合培养基对各虫态体表、体内、坑道内真菌进行分离培养,统计真菌检出率。对获得的真菌菌株通过形态学和分子生物学相结合的方法进行鉴定。在落叶松八齿小蠹虫体内外和坑道内共分离出真菌31种,其中接合菌3种,子囊菌8种,担子菌1种,半知菌19种。自各虫态体表共分离出真菌23种,体内共分离出真菌8种,31种真菌在坑道内均有检出。其中,Ceratocystis fujiensis为中国新记录种,Ophiostoma     

华山松大小蠹及其伴生蓝变真菌对华山松木质部危害的解剖学特征

为揭示华山松大小蠹和伴生蓝变真菌引起秦岭华山松枯萎的机制,选择秦岭北坡沣峪林场境35年树龄的健康华山松Pinus armandi为研究对象,对接种华山松大小蠹Dendroctonus armandi及与其伴生的蓝变真菌Ceratocystis polonica引起的寄主树木木质部形态变化进行了解剖观察。结果表明：接种致病性蓝变真菌C. polonica 1周后的4株华山松 的木质部组织内,蓝变区域显著增加,4～6周后蓝变区域不再增加; 而在接种无菌琼脂的2株对照华山松的木质部组织内,没有检测到蓝变区域。研究结果提示蓝变真菌C. polonica是致死秦岭华山松的重要病原菌,该伴生菌随华山松大小蠹入侵健康寄主华山松木质部组织,在木质部定居并分解木质部,堵塞树脂道,致使寄主华山松树脂代谢和水分代谢紊乱。该研究结果表明,虽然华山松大小蠹长期以来被认为是致死华山松的毁灭性小蠹虫,但是其共生蓝变真菌C. polonica对成熟华山松的致害作用不应该被忽视。     

套袋与未套袋苹果果实表皮及心部真菌种群结构与变化动态

2011年在山东海阳,2013年在蓬莱和栖霞选取当地常规管理的苹果园,采用传统组织分离法对套袋苹果、未套袋苹果的果实表皮及心部组织进行真菌分离并进行形态学和分子生物学鉴定。对不同时期采集的套袋及未套袋果实表皮与心部的真菌种类、菌落数量、组织分离率、多样性、相似性系数、相对分离频率等指标进行统计分析。结果表明,两个年度内从果实表皮共分离获得真菌43属,从心部获得真菌31属,相对分离频率较高的真菌包括：链格孢Alternaria spp.、枝状枝孢Cladosporium cladosporioides、镰孢菌Fusarium spp.、青霉菌Penicillium spp.等。研究结果表明：果实套袋后,在果实表皮定殖真菌的种类减少,多样性降低,而数量增加,组织带菌率升高;随果实生长,套袋果实表皮上的真菌种类与未套袋果实表皮真菌种类的相似度逐渐降低;7、8月份,套袋果实表皮上真菌种类明显减少,至8月底,套袋果实表面只有链格孢等少数几种优势真菌定殖。果实套袋后,定殖于果实心部的真菌种类和数量有所波动,套袋果和未套袋果上所分离真菌的相似度有所降低;5月底自果实心部分离真菌的种类和数量与9月底所分离真菌的种类和数量差异不大。     

光滑足距小蠹消化道的解剖结构

采用体视显微和扫描电镜技术研究光滑足距小蠹Xylosandrus germanus(Blandford)消化道的解剖结构。结果表明,光滑足距小蠹消化道由前肠、中肠和后肠三部分组成。成虫前胃由8个骨化的前胃板组成,呈灯笼状结构。前胃板由板状部和片状部组成,板状部短而简单,片状部甚长,由斜面、咀嚼刷和关闭刚毛组成。胃盲囊着生在中肠近后端,有细管状和囊状2种,成虫分别有1对,幼虫有1对细管状和3~5对囊状。6根马氏管分成2组,1组4根,另一组2根。6根马氏管与后肠肠壁形成隐肾系统。消化道具有1对囊状和1对细管状的胃盲囊可作为光滑足距小蠹成虫的识别特征。     

广西南宁市柑橘木虱虫生真菌种类调查

自柑橘木虱Diaphorina citri体上分离虫生真菌,通过形态特征和ITS序列分析,鉴定虫生真菌的种类;通过致病性测定,明确昆虫病原真菌种类。结果发现,自死体柑橘木虱上分离到18个虫生真菌菌株,隶属4种真菌;自活体上分离到985个虫生真菌菌株,隶属25种真菌。致病性测定结果发现,仅4种真菌对柑橘木虱成虫有致病性,包括刀孢蜡蚧菌Lecanicillium psalliotae、球孢白僵菌Beauveria bassiana、爪哇虫草Cordyceps javanica和淡紫紫孢菌Purpureocillium lilacinum,该4种真菌的分生孢子悬浮液（浓度5×10^7个孢子/mL）接种柑橘木虱成虫后10 d的累计死亡率分别为100%、100%、98.89%和43.33%。其中爪哇虫草仅自死体柑橘木虱上分离到,刀孢蜡蚧菌仅在活体上分离到,球孢白僵菌和淡紫紫孢菌在死体和活体上均被分离到。可见,柑橘木虱活体上的虫生真菌种类丰富。生产上应加强保护和利用昆虫病原真菌,提高其对柑橘木虱的自然抑制力。     

稻田飞虱卵寄生蜂群落结构和动态的初步研究

报道了广东省四会市大沙镇稻田中褐飞虱Nilaparvata lugens卵期寄生蜂的结构和动态。该群落由缨小蜂科和赤眼蜂科的6个属、共19种卵寄生蜂组成。其中,稻虱缨小蜂Anagrus nilaparvatae、长管稻虱缨小蜂A. longitubulosus和拟稻虱缨小蜂A. paranilaparvatae是群落中的优势种群,它们对控制褐飞虱种群卵期的存活率起主要作用。6个属在群落中的优势地位相对稳定,但不同物种包括优势种类在群落中的地位并不稳定。早、晚稻前期,群落的寄生蜂数量与稻田褐飞虱数量正相关;中期,寄生蜂数量在一定的范围内波动;后期,其数量先上升,然后急剧下降。水稻生长前、中和后期,寄生蜂对褐飞虱卵的平均寄生率分别约为76%,70%和50%。     

Plasticity of mycangia in Xylosandrus ambrosia beetles

Insects that depend on microbial mutualists evolved a variety of organs to transport the microsymbionts while dispersing. The ontogeny and variability of such organs is rarely studied, and the microsymbiont*s effects on the animal tissue development remain unknown in most cases. Ambrosia beetles (Coleoptera: Curculionidae: Scolytinae or Platypodinae) and their mutualistic fungi are an ideal system to study the animalfungus interactions. While the interspecific diversity of their fungus transport organ一 mycangia—is well-known, their developmental plasticity has been poorly described. To determine the ontogeny of the mycangium and the influence of the symbiotic fungus on the tissue development, we dissected by hand or scanned with micro-CT the mycangia in various developmental stages in five Xylosandrus ambrosia beetle species that possess a large, mesonotal mycangium: Xylosandrus amputatus. Xylosandrus compactus, Xylosandrus crassiusculus, Xylosandrus discolor, and Xylosandrus germanus. We processed 181 beetle samples from the United States and China. All five species displayed three stages of the mycangium development:(1) young teneral adults had an empty, deflated and cryptic mycangium without fungal mass;(2) in fully mature adults during dispersal, the promesonotal membrane was inflated, and most individuals developed a mycangium mostly filled with the symbiont, though size and symmetry varied;and (3) after successful establishment of their new galleries, most females discharged the bulk of the fun gal inoculum and deflated the mycangium. Experimental aposymbiotic individuals demonstrated that the pronotal membrane invaginated independently of the presence of the fungus, but the fungus was required for inflation. Mycangia are more dynamic than previously thought, and their morphological changes correspond to the phases of the symbiosis. Importantly, studies of the fungal symbionts or plant pathogen transmission in ambrosia beetles need to consider which developmental stage to sample. We provide illustrations of the different stages, including microphotography of dissections and micro-CT scans.     

Dynamics of the fungal symbionts in the gallery system and the mycangia of the ambrosia beetle,Xylosandrus mutilatus (Blandford) (Coleoptera: Scolytidae) in relation to its life history

The dynamics of the fungal symbionts in the gallery system and the mycangia of the ambrosia beetle,Xylosandrus mutilatus, were studied in relation to its life history using both isolation experiments and scanning electron microscopy (SEM). In the galleries,Ambrosiella sp. was predominant during the larval stages but its relative dominance gradually decreased during the development of the larvae. In contrast, yeasts (mainlyCandida sp.) andPaecilomyces sp. dominated continuously in the galleries after eclosion.Ambrosiella sp. was consistently stored in the mycangia in all adult stages, except in the teneral and overwintering adults when the other fungi were dominant. No fungal spores occurred in the mycangia of the adult beetles reared under aseptic conditions from the pupal stage, while onlyAmbrosiella sp. was stored in those reared from the teneral-adult stage. These results suggest that: (i) Xmutilatus is associated with at least three fungal species, among whichAmbrosiella sp. is the most essential food resource for development of the broods; (ii) immediately after eclosion, new female adults may take at least four associated fungal species, with no or incomplete selection, into their mycangia from the walls of the cradles; and (iii) conditions may well be produced in the mycangia of both matured and dispersing beetles whereby only the spores ofAmbrosiella sp. can proliferate.     

Patterns of functional enzyme activity in fungus farming ambrosia beetles

ABSTRACT: INTRODUCTION: In wood-dwelling fungus-farming weevils, the so-called ambrosia beetles, wood in the excavated tunnels is used as a medium for cultivating fungi by the combined action of digging larvae (which create more space for the fungi to grow) and of adults sowing and pruning the fungus. The beetles are obligately dependent on the fungus that provides essential vitamins, amino acids and sterols. However, to what extent microbial enzymes support fungus farming in ambrosia beetles is unknown. Here we measure (i) 13 plant cell-wall degrading enzymes in the fungus garden microbial consortium of the ambrosia beetle Xyleborinus saxesenii, including its primary fungal symbionts, in three compartments of laboratory maintained nests, at different time points after gallery foundation and (ii) four specific enzymes that may be either insect or microbially derived in X. saxesenii adult and larval individuals. RESULTS: We discovered that the activity of cellulases in ambrosia fungus gardens is relatively small compared to the activities of other cellulolytic enzymes. Enzyme activity in all compartments of the garden was mainly directed towards hemicellulose carbohydrates such as xylan, glucomannan and callose. Hemicellulolytic enzyme activity within the brood chamber increased with gallery age, whereas irrespective of the age of the gallery, the highest overall enzyme activity were detected in the gallery dump material expelled by the beetles. Interestingly endo-beta-1,3(4)-glucanase activity capable of callose degradation was identified in whole-body extracts of both larvae and adult X. saxesenii, whereas endo-beta-1,4-xylanase activity was exclusively detected in larvae. CONCLUSION: Similar to closely related fungi associated with bark beetles in phloem, the microbial symbionts of ambrosia beetles do not degrade cellulose. Instead, their enzyme activity is directed mainly towards comparatively more easily accessible hemicellulose components of the ray-parenchyma cells in the wood xylem. Furthermore, the detection of xylanolytic enzymes exclusively in larvae and not in adults indicates that larvae (pre-) digest plant cell wall structures exclusively in larvae (which feed on fungus colonized wood) and not in adults (which feed only on fungi). This implies that in X. saxesenii and likely also in many other ambrosia beetles, adults and larvae do not compete for the same food within their nests - in contrast, larvae increase colony fitness by facilitating enzymatic wood degradation and fungus cultivation.     

Biology of Hylobitelus xiaoi (Coleoptera: Curculionidae), a new pest of slash pine, Pinus elliottii

The biology of the weevil Hylobitelus xiaoi Zhang was studied in both field and laboratory in Shangyou, Jiangxi Province, China. This species required 2 yr to complete one generation with overwintering by adults in pupal chambers and larvae in galleries in the bark of host trees. Adults emerged from early March to early April and fed on the inner bark of branches of the trees. Adults fly little. Adults exhibited a diel periodicity, climbing up the trees around sunset and returning to the tree base the next morning. The mean preovipostion period was 46 d. Oviposition commenced in early May and ended in late August. The average fecundity per female was 36 eggs. Overwintered adult females and males lived 208 and 227 d, respectively. At 25 degrees C, the mean egg incubation period was 13 d. In the field, egg hatch occurred in 12-15 d with 83% survival. There were five to seven instars. At 25 degrees C, duration of the larval stage averaged 129 d. Pupation commenced in late August. At 25 degrees C, pupation averaged 20 d. In the field, pupation required 20-26 d. Transformation to adults occurred from late September to October. New adults remained in the pupal chambers until the next year. Infection by Beauveria bassiana Vuill. occurred in 0.8% of the pupae and 8.8% of the overwintered adults.     

Fungus Symbionts Colonizing the Galleries of the Ambrosia Beetle <Emphasis Type="Italic">Platypus quercivorus</Emphasis>

Isolations were made to determine the fungal symbionts colonizing Platypus quercivorus beetle galleries of dead or dying Quercus laurifolia, Castanopsis cuspidata, Quercus serrata, Quercus crispula, and Quercus robur. For these studies, logs from oak wilt-killed trees were collected from Kyoto Prefecture, Japan. Fungi were isolated from the: (1) entrances of beetle galleries, (2) vertical galleries, (3) lateral galleries, and (4) the larval cradle of P. quercivorus in each host tree. Among the fungus colonies which appeared on YM agar plates, 1,219 were isolated as the representative isolates for fungus species inhabiting in the galleries based on their cultural characteristics. The validity of the visual classification of the fungus colonies was checked and if necessary properly corrected using microsatellite-primed PCR fingerprints. The nucleotide sequence of the D1/D2 region of the large subunit nuclear rRNA gene detected 38 fungus species (104 strains) of which three species, i.e., Candida sp. 3, Candida kashinagacola (both yeasts), and the filamentous fungus Raffaelea quercivora were isolated from all the tree species. The two yeasts were most prevalent in the interior of galleries, regardless of host tree species, suggesting their close association with the beetle. A culture-independent method, terminal restriction fragment length polymorphism (T-RFLP) analysis was also used to characterize the fungus flora of beetle galleries. T-RFLP patterns showed that yeast species belonging to the genus Ambrosiozyma frequently occurred on the gallery walls along with the two Candida species. Ours is the first report showing the specific fungi inhabiting the galleries of a platypodid ambrosia beetle.     

The ambrosia symbiosis is specific in some species and promiscuous in others: evidence from community pyrosequencing

Symbioses are increasingly seen as dynamic ecosystems with multiple associates and varying fidelity. Symbiont specificity remains elusive in one of the most ecologically successful and economically damaging eukaryotic symbioses: the ambrosia symbiosis of wood-boring beetles and fungi. We used multiplexed pyrosequencing of amplified internal transcribed spacer II (ITS2) ribosomal DNA (rDNA) libraries to document the communities of fungal associates and symbionts inside the mycangia (fungus transfer organ) of three ambrosia beetle species, Xyleborus affinis, Xyleborus ferrugineus and Xylosandrus crassiusculus. We processed 93 beetle samples from 5 locations across Florida, including reference communities. Fungal communities within mycangia included 14–20 fungus species, many more than reported by culture-based studies. We recovered previously known nutritional symbionts as members of the core community. We also detected several other fungal taxa that are equally frequent but whose function is unknown and many other transient species. The composition of fungal assemblages was significantly correlated with beetle species but not with locality. The type of mycangium appears to determine specificity: two Xyleborus with mandibular mycangia had multiple dominant associates with even abundances; Xylosandrus crassiusculus (mesonotal mycangium) communities were dominated by a single symbiont, Ambrosiella sp. Beetle mycangia also carried many fungi from the environment, including plant pathogens and endophytes. The ITS2 marker proved useful for ecological analyses, but the taxonomic resolution was limited to fungal genus or family, particularly in Ophiostomatales, which are under-represented in our amplicons as well as in public databases. This initial analysis of three beetle species suggests that each clade of ambrosia beetles and each mycangium type may support a functionally and taxonomically distinct symbiosis.     

Reproduction of the ambrosia beetle, Xyleborus pfeili (Ratzeburg) (Col., Scolytidae), on semi-artificial diet

Abstract: Reproduction of the ambrosia beetle Xyleborus pfeili (Ratzeburg), in relation to galley formation, was examined by artificial rearing in test tubes. Unmated females produced only male offspring, while broods that originated from fertilized females had strongly female-biased sex ratios. Thus, the reproductive process of X. pfeili is arrhenotokous parthenogenesis. Oviposition took place over a long time, as eggs were present in the tunnels throughout the experiments (up to 40 days after inoculation). Total length of a gallery system and number of offspring per tube were positively correlated. Pupation and eclosion of males were later than those of some females. In the case of two males (offspring in pupal and/or adult stages) in the same gallery system, most of the males coexisted in the condition of both different stages and different branch tunnels. These results imply that a mother beetle of X. pfeili determines the number of her eggs in response to the size of each branch tunnel (= amount of ambrosia fungus), and produces at least one male egg in the tunnel after laying some female eggs.