储存条件对花绒寄甲成虫寿命及产卵量的影响

花绒寄甲Dastarcus helophoroides Fairmaire是天牛类林木蛀干害虫的重要天敌昆虫,释放成虫是利用该天敌控制害虫的重要手段之一。为保持成虫释放时仍具有有效活力,本文研究了成虫在释放前的储存温度和储存时长对其产卵量和寿命的影响。试验采用饲喂和未饲喂的成虫在16±1℃、12±1℃、8±1℃和4±1℃下储存,测定成虫的死亡率,同时测试成虫在同一储存温度下保存不同时长后的产卵量与寿命。结果显示,成虫在12℃储存条件下死亡率最低,且羽化后的新成虫在储存前未饲喂更利于其存活。经历不同的储存时间后,花绒寄甲的产卵量均随时间变化呈现先升后降的规律,且不同储存时长的累积产卵量差异显著（F7,16=83.12, P<0.001）其中储存60 d的成虫产卵量最高,各处理间的累积死亡率差异显著（F7,16=277.82, P<0.001）,其中储存60 d的死亡率最低为38%。储存温度与时长对花绒寄甲成虫寿命及产卵量有显著影响,成虫适合在12℃条件下保存,保存时长在60 d效果最好。     

接种量对花绒寄甲繁殖的影响

释放花绒寄甲防治天牛已成为重要手段,而繁殖花绒寄甲时,接种花绒寄甲幼虫到大麦虫蛹体时,控制合适的接种量是提高花绒寄甲繁殖数量和质量的关键技术。本研究通过在替代寄主上人工接种不同数量的花绒寄甲幼虫,观察其发育情况及其子代数量、质量等指标,明确最佳接种量。结果表明：随着接种量的增加,花绒寄甲幼虫历期和蛹历期明显缩短,其中接种4头/个和6头/个,幼虫历期为13 d,蛹历期为33 d,而接种14头/个和16头/个时,幼虫历期短于12 d,蛹历期明显缩短为28~29 d。花绒寄甲结茧数随接种量增加而增加,接种数为16头/个时,结茧数最多,接近7个。花绒寄甲结茧率随着接种量增多而降低,4头/个时,结茧率最高为72.3%。接种量对花绒寄甲子代个体数量和大小均有显著影响,其中接种8头/个时,羽化数平均为4.3头,显著高于接种4头/个（羽化数平均为2.8头）,明显低于接种16头/个(羽化数平均为6.9头)。接种量为4头/个和6头/个时,子代成虫个体最大,单头重平均每头可达0.035 g,接种量为8头/个时,成虫单头重平均每头0.032 g左右,接种量达到16头/个时,单头重最轻,为0.023 g。对花绒寄甲羽化率无显著影响,7个处理下子代羽化率均较高,平均在94.4%~100%。接种量越少,更利于花绒寄甲的生长发育,当接种量为4头/个时,花绒寄甲成虫发育最好,其子代个体最大,但子代数较少。因此,利用大麦虫蛹繁育花绒寄甲种虫时,最佳接种量为4头/个,而需要规模化繁育花绒寄甲作为天敌使用时,综合考虑子代数量和质量以及经济成本,最佳接种量为8头/个。     

广东地区花绒寄甲替代寄主的研究

将花绒寄甲Dastarcus heloporoides Fairmaire幼虫接于替代寄主黄粉甲Tenebrio molitor、吉丁虫Buprestidaesp和大麦虫Zophobas morio,结果表明,黄粉甲幼虫、蛹和成虫均能繁育出花绒寄甲成虫,平均羽化率能达到20%以上,是较好的替代寄主.用黄粉甲繁育的花绒寄...     

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。     

外寄生性花绒寄甲的寄生选择及其发育表现

"选择-表现"假说认为,成虫应该选择有利于子代发育的高品质寄主,但在寄主选择中,除了寄主品质外,其他因素也可能影响寄主选择决策。寄主选择研究通常以成虫为对象,而对那些初龄幼虫选择寄主的寄生性昆虫很少关注。以1龄幼虫积极搜寻寄主的寄生性花绒寄甲为模式生物,采用双选试验设计,观察了花绒寄甲初孵幼虫在不同体重青杨天牛幼虫之间、在已被寄生与健康的黄粉虫蛹之间的寄生选择性;然后采用回归设计,观察了花绒寄甲寄生若干不同体重的青杨天牛幼虫后的发育表现。研究结果表明,花绒寄甲1龄幼虫对体型较大的青杨天牛幼虫的选择偏好显著大于对体型较小的寄主幼虫的选择,选择大体型幼虫的比值比是选择小体型幼虫的4.55倍;对已被寄生的寄主黄粉虫蛹的选择偏好显著大于对健康寄主蛹的选择,选择已被寄生寄主的比值比是选择健康寄主的12.57倍。寄生青杨天牛幼虫的花绒寄甲幼虫发育历期平均为11.49 d、蛹历期为26.67 d、幼虫发育至成虫的羽化率50%,这些发育表现与寄生时青杨天牛幼虫的体重没有显著关系。但刚羽化寄甲成虫体重与寄生时寄主的体重存在显著的正直线关系:寄生时的寄主体重每增大0.01 g,羽化出的寄甲成虫体重增大近0.08%;方差分析寄甲成虫体重在不同寄主体重水平之间的差异表明,从体型较大寄主中羽化的寄甲成虫体重显著大于从体型较小寄主中羽化的成虫。研究结果说明,花绒寄甲初孵幼虫在寄主选择决策时,在寄主体型大小与被寄生状态之间可能采取折衷对策,而且对体型大小不同的寄主选择与子代发育适合度表现存在一致性,从而支持"选择-表现"假说。     

吉林珲春地区利用花绒寄甲防治光肩星天牛的可行性研究

【目的】探究光肩星天牛Anoplophora glabripennis(ALB)在吉林珲春的耐寒性,为实现在当地释放花绒寄甲Dastarcus helophoroides防治ALB提供理论基础。【方法】于吉林珲春采集被ALB危害的杨树木段,室内解剖木段后收集各虫态/龄期ALB,并测量这些天牛的过冷却点。通过设置同一时间(0.5 h)下0、4和8℃不同驯化温度和最适驯化温度下0.5、1和4 h不同驯化时间,以明确花绒寄甲成虫的过冷却能力受驯化温度和驯化时间的影响。将上述两组数据进行综合,分析ALB大幼虫与不同冷驯化条件下花绒寄甲成虫过冷却点的相关性。【结果】ALB卵(分布在树皮表层)的过冷却点最低,随着其不断发育并向树内蛀食,其过冷却点逐渐升高,即不同虫态/龄期的过冷却点大小顺序为卵?小幼虫(100mg以下)?大幼虫(500 mg以上)。花绒寄甲成虫的过冷却能力受低温驯化影响明显,4℃条件下冷驯化0.5 h时最易提高其耐寒性。ALB大幼虫的过冷却点显著高于0(0.5 h)、4(0.5 h)、8(0.5 h)和4℃(1 h)冷驯化条件下处理的花绒寄甲成虫。【结论】ALB能以高于当地最低温的过冷却点越冬,除受自身耐寒能力影响外,还与所处微生境有关。而花绒寄甲成虫在经历一定时间的快速冷驯化处理后,过冷却点显著降低,耐寒性得到明显提高。表明吉林珲春等高纬度地区利用花绒寄甲防治ALB存在较大的可行性。     

外源海藻糖对花绒寄甲成虫存活和耐寒性的影响

【目的】探讨取食不同浓度外源海藻糖对室内饲养的花绒寄甲 Dastarcus helophoroides 成虫存活和耐寒性的影响。【方法】在室内分别用含3%, 6%和9%海藻糖的半人工饲料饲养花绒寄甲成虫,以取食不含海藻糖的半人工饲料的花绒寄甲成虫为对照组,统计饲养10周后的存活率,测定未经低温处理和10℃低温处理3 d的成虫过冷却点和含水量。【结果】取食含6%海藻糖的半人工饲料的花绒寄甲成虫存活率最高,为86.67%。不管是否经低温处理,取食含9%海藻糖的半人工饲料的成虫与取食含3%和6%海藻糖的半人工饲料的成虫以及不含海藻糖的半人工饲料的成虫(对照)相比,其过冷却点均最低,其中未经低温处理的成虫过冷却点为-19.30℃,而经低温处理的成虫过冷却点为-21.60℃。低温处理对取食不含海藻糖的半人工饲料的成虫的含水量有显著影响,而对取食含海藻糖的半人工饲料的成虫含水量无显著影响。【结论】外源海藻糖对花绒寄甲成虫的存活和过冷却点有显著影响,可以利用外源海藻糖提高室内饲养花绒寄甲成虫的存活率和耐寒性。     

影响松褐天牛羽化率的关键因子研究

为了研究明确林间释放花绒寄甲Dastarcus helophoroides Fairmaire后影响松褐天牛Monochamus alternatus Hope羽化率的关键因子,本文在试验地不同位置设置诱木引诱松褐天牛成虫产卵,并在诱木上释放花绒寄甲成虫,之后调查诱木的生长环境及诱木上花绒寄甲的寄生率、其他天敌寄生率,并对各因子与松褐天牛羽化率进行逐步回归分析,筛选出关键因子。结果表明,影响松褐天牛羽化率(Y)的关键因子是花绒寄甲寄生率(X_(16))和其它天敌寄生率(X_(15)),两者与松褐天牛羽化率均呈显著负相关关系。依此建立多元回归模型:Y=1.0194-0.6608 X_(15)-0.8665 X_(16)。经检验,平均差异程度为0.2573。以上研究,证实了释放花绒寄甲对松褐天牛的种群起到了重要控制作用。     

白星花金龟室内外繁育技术研究

[目的]根据新疆气候特点和白星花金龟Protaetia brevitarsis Lewis生物学特性,探究在新疆人工繁育白星花金龟的可行性及潜力,以期为白星花金龟在新疆的人工繁殖和转化利用畜禽粪便提供科学依据.[方法]以牛粪为繁育基质,在适宜季节分别在室内外保育白星花金龟的蛹及作为成虫产卵基质,最终统计比较室内外成虫的羽化及产卵情况.[结果]室外露天条件更利于白星花金龟的羽化,老熟幼虫做土室26 d后羽化出成虫,比室内及室外棚下处理提前4d.在化蛹30d后进入羽化高峰期,持续13d,羽化率83％.成虫雌雄比接近1∶1,雌虫羽化时间早于雄虫1-3 d.白星花金龟成虫室内外产卵量差异不显著(P＜0.05),室内单雌产卵量109.80粒,室外105.94粒,成虫羽化后30-35 d进入产卵高峰期,第60天室内外成虫产卵量显著下降(P＜0.05),甚至不产卵.[结论]白星花金龟规模化人工繁育在新疆是可行性的,在室外自然条件和室内控温条件下白星花金龟繁育的效果差异不显著.     

不同寄主来源种群花绒寄甲成虫对桃红颈天牛幼虫虫粪的行为趋性和种群控制效果

【目的】桃红颈天牛Aromia bungii是危害桃、杏、李、樱桃的主要蛀干害虫,花绒寄甲Dastarcus helophoroides是一种能有效防治多种天牛类林木钻蛀害虫的重要天敌昆虫。本研究通过比较不同寄主来源种群花绒寄甲对桃红颈天牛幼虫虫粪的行为反应和对幼虫控制能力的差异,旨在筛选能够有效防治桃红颈天牛的花绒寄甲种群。【方法】采用Y型嗅觉仪测定了6个不同寄主来源种群花绒寄甲成虫对桃红颈天牛幼虫虫粪的行为趋性;采用纱网罩受害原木模拟自然条件,释放不同种群花绒寄甲成虫测定了其对桃红颈天牛的致死效果。【结果】行为趋性结果表明,源自松褐天牛和云斑天牛的花绒寄甲种群对桃红颈天牛幼虫虫粪表现出明显的正趋向反应,而源自光肩星天牛、星天牛、锈色粒肩天牛和栗山天牛这4个种群的花绒寄甲对桃红颈天牛幼虫虫粪均未表现出明显的趋向反应。持续2年的寄生控制实验表明,源自光肩星天牛的花绒寄甲种群致死效果较好,天牛死亡率为52.86%±5.97%,源自松褐天牛、云斑天牛、栗山天牛和锈色粒肩天牛的花绒寄甲种群控制效果依次降低,天牛死亡率分别为35.14%±5.55%,32.88%±5.50%,26.09%±5.29%和10.94%±3.90%,源自星天牛的花绒寄甲种群未显示出对桃红颈天牛的控制作用。【结论】利用花绒寄甲防治桃红颈天牛时,应选择源自松褐天牛、云斑天牛或光肩星天牛的花绒寄甲种群。     

壳聚糖酶的克隆表达与壳寡糖的制备分析

目的:克隆壳聚糖酶基因于大肠杆菌中实现高表达,制备壳寡糖。方法:以枯草芽孢杆菌总DNA为模板扩增壳聚糖酶基因(CSN),克隆至载体pET23a(+)上,转化菌株BL21(DE3)。重组子经0.5 mmol/L IPTG诱导后,SDS-PAGE和质谱检测与鉴定重组酶。酶纯化后水解壳聚糖,薄层色谱分析其水解产物。结果:质谱证明壳聚糖酶(31.5kDa)成功表达,表达量占菌体总蛋白的45%左右。纯化后重组酶浓度为900 mg/L,纯度95%、回收率85%,酶活力为10 000 U/mg。壳聚糖降解产物为壳二糖至壳四糖。结论:原核表达载体pET23a(+)-CSN构建正确,壳聚糖酶表达量与活性高,适用于水解壳聚糖制备壳寡糖。     

国内外蝗害治理技术现状与展望

本文首先概述了国内外蝗虫发生与为害的态势,总结了现阶段我国蝗虫发生与为害的主要特点:即农田飞蝗暴发频繁而且严重,草原土蝗的发生时常造成严重的经济损失,而且侵入城市干扰市民生活,我国与周边国家之间蝗虫过境迁移频繁,使用化学农药污染环境和农产品;分析了国内外蝗虫防治对策与技术的发展现状,重点介绍了应急防治和可持续治理对策、...     

Molecular characterisation of species and genotypes of Cryptosporidium and Giardia and assessment of zoonotic transmission

The molecular characterisation of species and genotypes of Cryptosporidium and Giardia is essential for accurately identifying organisms and assessing zoonotic transmission. Results of recent molecular epidemiological studies strongly suggest that zoonotic transmission plays an important role in cryptosporidiosis epidemiology. In such cases the most prevalent zoonotic species is Cryptosporidium parvum. Genotyping and subtyping data suggest that zoonotic transmission is not as prevalent in the epidemiology of giardiasis. Molecular characterisation of Cryptosporidium and Giardia is a relatively recent application that is evolving as new genes are found that increase the accuracy of identification while discovering a greater diversity of species and yet unnamed taxa within these two important genera. As molecular data accumulate, our understanding of the role of zoonotic transmission in epidemiology and clinical manifestations is becoming clearer.     

Comparison of BMI and percentage of body fat of Indian and German children and adolescents

Today, serious health problems as overweight and obesity are not just constricted to the developed world, but also increase in the developing countries (Prentice 2006, Ramachandram et al. 2002). Focusing on this issue, BMI and percentage of body fat were compared in 2094 schoolchildren from two cross-sectional studies from India and Germany investigated in 2008 and 2009. The German children are in all age groups significantly taller, whereas the Indian children show higher values in BMI (e.g. 12 years: Indian: around 22 kg/m2; German: around 19 kg/m2) and in the percentage of body fat (e.g. 12 years: Indian: around 27%; German: around 18-20%) in most of the investigated age groups. The Indian children have significantly higher BMI between 10 and 13 (boys) respectively 14 years (girls). Indian children showed significant higher percentage of body fat between 10 and 15 years (boys) and between 8 and 16 years (girls). The difference in overweight between Indian and German children was strongest at 11 (boys) and 12 (girls) years: 70% of the Indian but 20% of the German children were classified as overweight. In countries such as India that undergo nutritional transition, a rapid increase in obesity and overweight is observed. In contrast to the industrialized countries, the risk of overweight in developing countries is associated with high socioeconomic status. Other reasons of the rapid increase of overweight in the developing countries caused by different environmental or genetic factors are discussed.     

Synthesis and turnover of cerebrosides and phosphatidylserine of myelin and microsomal fractions of adult and developing rat brain.

The synthesis and turnover of cerebrosides and phospholipids was followed in microsomal and myelin fractions of developing and adult rat brains after an intracerebral injection of [U-14C]serine. The kinetics of incorporation of radioactivity into microsomal and myelin cerebrosides indicate the possibility of a precursor-product relationship between cerebrosides of these membranes. The specific radioactivity of myelin cerebrosides was corrected for the deposition of newly formed cerebrosides in myelin. Multiphasic curves were obtained for the decline in specific radioactivity of myelin and microsomal cerebrosides, suggesting different cerebroside pools in these membranes. The half-life of the fast turning-over pool of cerebrosides of myelin was 7 and 22 days for the developing and adult rat brain respectively. The half-life of the slowly turning-over pool of myelin cerebrosides was about 145 days for both groups of animals. The half-life of the rapidly turning-over microsomal cerebrosides was calculated to be 20 and 40 h for the developing and adult animals respectively. The half-life of the intermediate and slowly turning-over microsomal cerebrosides was 11 and 60 days respectively, for both groups of animals. The amount of incorporation of radioactivity into microsomal cerebrosides from L-serine was greatly decreased in the adult animals, and greater amounts of the precursor were directed towards the synthesis of phosphatidylserine. In the developing animals, considerable amounts of cerebrosides were synthesized from L-serine, besides phosphatidylserine. The time-course of incorporation indicated that a precursor-product relationship exists between microsomal and myelin phosphatidylserine. The half-life of microsomal phosphatidylserine was calculated to be about 8 h for the fast turning-over pool in both groups of animals.     

Identification and composition of the tonsillar and anal enterococcal and streptococcal flora of dogs and cats

Enterococcus faecalis was the most frequently isolated enterococcal species from anal swabs and tonsils of dogs and cats, although in the anal samples from dogs Ent. hirae was found almost as often as Ent. faecalis. Most Ent.faecium strains from dog tonsils differed from those associated with humans and other animals in that they fermented sorbitol. Typical Ent. avium as well as atypical Ent. avium -like strains were seen in dogs, while the related species Ent. raffinosus was associated with cat tonsils. Enterococcus cecorum also occurred mainly in cats. Certain atypical strains, presumptively identified as Ent. cecorum , shared characteristics with Ent. columbae.
The most frequent streptococcal species in tonsils of cats and dogs were Streptococcus suis and Strep. canis. Streptococcus canis and Strep. bovis predominated in anal swabs. The canine Strep. suis differed from the common porcine strains in fermenting mannitol.
Forty-seven of the 288 isolates examined could not be identified or related to known species. The characteristics of two groups of these bacteria, provisionally called 'Ton 31 group' and 'O7 group' are described.