橘小实蝇田间消长动态及对柑橘果实危害研究

【目的】找出橘小食蝇Bactrocera dorsalis(Hendel)在桂林东郊柑橘果园的消长规律,掌握橘小实蝇对不同柑橘品种的危害程度。【方法】2012-2013年,利用橘小实蝇性诱器对桂林东郊柑橘果园的橘小实蝇田间动态进行监测,收集逐旬诱虫数量,并制作周年诱虫消长曲线,分析橘小实蝇消长规律。选取果园内18个早中晚熟柑橘品种进行橘小实蝇危害调查,从果实受害前到果实成熟采收,统计各个品种的逐旬虫果数量,分析各品种受害情况。【结果】田间橘小实蝇成虫5月开始出现,9月下旬-10月上旬达到高峰期,12月中下旬活动减弱或停止。早中熟柑橘品种受橘小实蝇的危害率多在26.72%-73.19%,而晚熟品种多在16.08%以下。宽皮柑橘类受橘小实蝇的危害率多在15.23%以上,而橙类和杂柑类低于10.81%。早熟品种从7-8月开始受橘小实蝇危害,一直持续到果实成熟,受害程度逐步加重。中晚熟品种10月中下旬后开始受害,在11月上旬到12月上旬之间有1-2个受害高峰期,12月中下旬受害减轻。同一品种在不同年份的受害开始时间、高峰期、低谷期不完全相同。【结论】橘小实蝇成虫在春季条件适合时开始活动,在秋季达到活动高峰期,在冬季气温下降等不利条件下活动减弱或停止。橘小实蝇对柑橘早中熟品种的危害率高于晚熟品种,对宽皮柑橘类的危害率高于橙类。在果实生长成熟过程中,早熟品种随果实成熟度增高受害程度加重,中晚熟品种受害高峰期出现在果实成熟中、前期,同年内成熟期相同品种的受害消长走势基本相同,同一品种在不同年份的受害消长走势不同。     

植物果实、颜色和形状对橘小实蝇产卵选择的影响

橘小实蝇Bactrocera dorsalis(Hendel)是近几年入侵江苏南部地区,严重危害当地水果、蔬菜的重要害虫。为深入了解其在该地区果树、蔬菜上的产卵特性,进行植物果实、颜色和形状对其产卵选择影响的研究。实验室中"纸杯法"的产卵选择试验结果表明,橘小实蝇对不同水果的产卵偏好性由高到低依次为:柑橘、香蕉、芒果、枣、石榴、苹果、桃子、梨、李、葡萄、柿;对不同蔬菜的产卵偏好性由高到低依次为:丝瓜、豇豆、苦瓜、黄瓜、茄子、南瓜、青椒、番茄。对不同寄主颜色和形状的产卵选择特点为,雌虫常选择桔黄色、绿色,以及圆球形的寄主产卵,而较少选择黑色、方形的寄主产卵。从试验结果可以看出,寄主果实散发出的气味,及其颜色和形状对橘小实蝇的产卵选择有影响。     

瓜果上主要实蝇类害虫PCR-RFLP分子鉴定技术的建立及应用

[目的]建立一种针对实蝇幼虫快速鉴定的技术方法,并应用该技术以明确我国瓜果上主要实蝇类害虫的优势种.[方法]以我国瓜果蔬菜上危害最为严重的瓜实蝇Bactrocera cucurbitae(Coquillett)、南亚果实蝇Bactrocera tau Walker和橘小实蝇Bactrocera dorsalis(Hendel)为对象,基于3种实蝇种间存在线粒体细胞色素氧化酶亚基Ⅰ因子(mtCOⅠ)基因的序列差异,利用3种限制性内切酶SapⅠ、BsmⅠ和Sac Ⅰ酶切识别这些差异序列的特异性酶切位点,根据酶切后mtCOⅠ基因片段大小不同,对3种实蝇进行快速的鉴定识别,并进一步应用此技术对来自我国7省11市的7种瓜菜和2种水果上的21份实蝇幼虫样本进行鉴定.[结果]通过单独或组合酶切的方式建立了一套针对瓜实蝇、南亚果实蝇和橘小实蝇的PCR-RFLP快速分子鉴定技术,并将此方法应用于田间监测.田间鉴定结果表明,湖北、湖南、浙江等地区危害瓜菜的实蝇主要是南亚果实蝇,广东、广西、海南等地区瓜菜上的实蝇种类主要是瓜实蝇,且瓜实蝇和南亚果实蝇存在寄主重叠现象,云南危害火龙果和芒果等水果上的实蝇主要是橘小实蝇.[结论]本研究建立的瓜实蝇、南亚果实蝇和橘小实蝇的识别鉴定方法,因不受虫体、虫态的影响,且具有低成本、高效、快速、重复性好的特点,适用于田间瓜果上实蝇样本的快速诊断检测.依据田间鉴定结果,预测近年来瓜实蝇可能有逐渐向北扩散的趋势.     

橘小实蝇和番石榴实蝇卵的提取物对两种实蝇行为的影响及化学成分分析

[目的]探究橘小实蝇Bactrocera dorsalis和番石榴实蝇Bactrocera correcta卵提取物对2种实蝇雌虫行为的影响,以及2种实蝇卵表面化合物的差异,为2种实蝇的化学生态防治提供理论依据.[方法]利用Y型嗅觉仪测定了橘小实蝇交配雌虫和番石榴实蝇交配雌虫对卵表提取物的行为反应,并利用EthoVision XT软件分析雌虫在Y管内的运动轨迹;利用气相色谱-质谱联用仪(GC-MS)鉴定分析橘小实蝇卵和番石榴实蝇卵的化合物成分,并利用标准曲线法测定了各组分的含量.[结果]橘小实蝇卵提取物对橘小实蝇交配雌虫具有显著引诱作用(x2=9.383,P=-0.002),对番石榴实蝇交配雌虫具有显著驱避作用(x2=6.737,P=0.009),番石榴实蝇卵提取物对番石榴实蝇交配雌虫(x2=4.235,P=0.040)和橘小实蝇交配雌虫都具有引诱作用(x2=5.818,P=0.016).从橘小实蝇卵表提取物中共鉴定出11种化合物,分别是茴香脑、十五烷、十二烷酸、十二酸乙酯、(Z)-11-十四碳烯酸、十四烷酸、十四酸乙酯、(E)-9-十六碳烯酸乙酯、十六烷酸、十八碳烯酸、(Z)-9-十八碳烯酸乙酯.从番石榴实蝇卵表提取物中仅鉴定出7种化合物,而且这7种化合物在橘小实蝇的卵提取物中都存在.仅存在于橘小实蝇卵表的4种化合物是茴香脑、十二烷酸、十二酸乙酯、(Z)-11-十四碳烯酸.在2种实蝇卵提取物的相同成分中,十四烷酸、(E)-9-十六碳烯酸乙酯、十六烷酸在橘小实蝇卵表的含量显著高于番石榴实蝇.[结论]番石榴实蝇具有通过卵表化合物识别同种卵和异种卵的能力,2种实蝇的卵表化合物具有明显的差异.     

中国实蝇记述(三)

本文记述实蝇亚科小条实蝇族(Ceratitini)的我国种属,计8属20种,其中两个新属,七个新种,另有一属二种是我国的新纪录。新种模式标本保存在中国科学院动物研究所。 本族种类虽不算多,但经济意义很大,世界著名的果树害虫地中海实蝇Ceratitiscapitata Wied.是本族的一员。此蝇食性广泛,为害多种果实,如柑桔、苹果、李、桃、梨、柿,以至葡萄、咖啡等等,其全部已知寄主,包括栽培的和野生的植物,不下百种之多;又因     

橘小实蝇对五个芒果品种的产卵偏好及清理落果防治效果研究

在2011年6—8月调查了橘小实蝇Bactrocera dorsalis(Hendel)对云南省元江县5个主要芒果品种的产卵为害情况,评估了清理落果对橘小实蝇的防治效果。结果表明树上果实和成熟落果受害率最高、产卵孔数量最多的品种是三年芒和红象牙芒;单位面积落果量(X)和监测雄虫数量(Y)显著相关(r1=0.884**,显著性P1=0.000),其回归方程为Y=-1.675+449.701X-204.933X2+27.046X3(R2=0.966,显著性水平P=0.000);累加虫量(X)与树上果实被害率(Y)的回归方程为Y=0.003X0.721(R2=0.953,P=0.000)。采拾落果可降低树上果实受害率约20%,减少田间虫口数44%左右。因此,清理落果对控制橘小实蝇田间种群数量、减少树上果实被害率有显著作用。     

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。     

橘小实蝇成虫肠道可培养细菌群落结构分析

【目的】研究橘小实蝇(Bactrocera dorsalis) 3个种群(实验室正常喂养种群、实验室无菌糖水喂养种群和野生种群)成虫肠道可培养细菌的群落结构组成。【方法】利用16S rRNA基因的聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)分析技术,结合菌落形态观察和生理生化特征鉴定细菌种类。【结果】从橘小实蝇3个种群成虫肠道600株可培养细菌得到53种不同细菌遗传型,分属于肠杆菌科(Enterobacteriaceae)、肠球菌科(Enterococcaceae)和芽孢杆菌科(Bacillaceae)等3个科。其中肠杆菌科是肠道可培养细菌最优势的细菌种类。同样以序列相似性大于97%的菌株归为相同的细菌种类为标准,找到了橘小实蝇3个种群可培养细菌的共有菌种,结合菌落形态观察和生理生化特征鉴定,确定共有菌种为肠杆菌属5株,克雷伯氏菌属2株,柠檬酸杆菌属1株,泛菌属1株,肠球菌属2株,以及芽孢杆菌属4株。【结论】通过研究橘小实蝇成虫肠道可培养细菌群落结构组成,可为探讨肠道菌群对寄主的生理功能和生态学意义奠定基础,最终为利用微生物防治此类害虫提供新思路。     

关中麦秆蝇的初步研究

麦秆蝇是小麦主要害虫之一,陕西关中地区每年发生4代。成虫盛发期在4月中下旬,5月下旬至6月中旬,7月中下旬,9月下旬至10月上旬,以幼虫在麦苗幼茎内越冬。寄主以小麦为主,大麦为次。每年秋苗期和春季拔节至孕穗期两次为害小麦。麦收后以落粒自生麦苗为夏季寄主。成虫羽化在早晨6—8时盛;羽化后取食补充性营养;苗期产卵在芽鞘上、拔节后在顶端第2、3叶基为多。幼由在苗期和拔节期入侵率高,孕穗期为次,抽穗以后不能入侵,在不同生育期植株上,入侵后表现害状不同。麦秆蝇的为害程度与栽培条件关系密切:早播小麦秋苗期受害重,晚播小麦在春季受害重;合理灌水、密植受害轻:施肥充足、土壤肥沃、生长良好的小麦受害轻。成虫发生期是药剂防治的良好时期。γ666粉剂、烟剂、液剂杀成虫均良好,E605既能杀成虫又具一定的杀卵能力。     

延迟交配对橘小实蝇繁殖适度的影响

橘小实蝇Bactrocera dorsalis Hendel是一种世界性的入侵害虫,严重为害多种经济果蔬。本文通过响应面分析方法,研究了延迟交配对橘小实蝇交配率、产卵量、孵化率和寿命的影响。结果表明,交配率随雌虫交配日龄的延迟先增后减,雌、雄成虫均为35日龄处理组中的交配率最高,为81.00%±2.00%;而雄虫交配日龄的延迟则对其卵孵化率有明显的负面作用,在56日龄雄虫与35日龄雌虫处理组中,其卵孵化率最低,仅为27.56%±4.55%。雌成虫产卵量和寿命受到雌、雄虫双方交配日龄的的影响,产卵量（y）与雄虫日龄（x1）和雌虫日龄（x2）的回归方程为y=514.36+3.08x1-11.05x2,雌成虫寿命（y）与雄虫日龄（x1）和雌虫日龄（x2）的回归方程为y=35.85+0.23x1+0.40x2。研究结果为田间使用性信息素迷向法防治橘小实蝇提供了理论依据。     

Role for dopamine in malonate-induced damage in vivo in striatum and in vitro in mesencephalic cultures

Defects in mitochondrial energy metabolism have been implicated in the pathology of several neurodegenerative disorders. In addition, the reactive metabolites generated from the metabolism and oxidation of the neurotransmitter dopamine (DA) are thought to contribute to the damage to neurons of the basal ganglia. We have previously demonstrated that infusions of the metabolic inhibitor malonate into the striata of mice or rats produce degeneration of DA nerve terminals. In the present studies, we demonstrate that an intrastriatal infusion of malonate induces a substantial increase in DA efflux in awake, behaving mice as measured by in vivo microdialysis. Furthermore, pretreatment of mice with tetrabenazine (TBZ) or the TBZ analogue Ro 4-1284 (Ro-4), compounds that reversibly inhibit the vesicular storage of DA, attenuates the malonate-induced DA efflux as well as the damage to DA nerve terminals. Consistent with these findings, the damage to both DA and GABA neurons in mesencephalic cultures by malonate exposure was attenuated by pretreatment with TBZ or Ro-4. Treatment with these compounds did not affect the formation of free radicals or the inhibition of oxidative phosphorylation resulting from malonate exposure alone. Our data suggest that DA plays an important role in the neurotoxicity produced by malonate. These findings provide direct evidence that inhibition of succinate dehydrogenase causes an increase in extracellular DA levels and indicate that bioenergetic defects may contribute to the pathogenesis of chronic neurodegenerative diseases through a mechanism involving DA.     

Scurvy in capybaras bred in captivity in Argentine

In order to determine if the absence of vitamin C in the diet of capybaras (Hydrochoerus hydrochaeris) causes scurvy, a group of seven young individuals were fed food pellets without ascorbic acid, while another group of eight individuals received the same food with 1 g of ascorbic acid per animal per day. Animals in the first group developed signs of scurvy-like gingivitis, breaking of the incisors and death of one animal. Clinical signs appeared between 25 and 104 days from the beginning of the trial in all individuals. Growth rates of individuals deprived of vitamin C was considerably less than those observed in the control group. Deficiency of ascorbic acid had a severe effect on reproduction of another population of captive capybaras. We found that the decrease in ascorbic acid content in the diet affected pregnancy, especially during the first stages. The results obtained suggest that it is necessary to supply a suitable quantity of vitamin C in the diet of this species in captivity.     

Changes in lactate dehydrogenase activity in chicken tissues in hyperthyreosis in ontogenesis

The lactate dehydrogenase activity in reactions of lactate oxidation and synthesis was studied in subfractions of the chicken brain, heart and liver at the embryonal, early postembryonal and adult stages of development after thyroxine administration. It has been shown that during embryogenesis thyroxine predominantly enhanced the rate of lactate oxidation in the mitochondrial tissues. A marked increase in the lactate synthesis was found in cytoplasm of the adult chicken tissues. Specificity of enzyme activity alterations was detected in the chicken brain during ontogenesis after thyroxine administration.     

SSTR5 ablation in islet results in alterations in glucose homeostasis in mice

Somatostatin (SST) peptide is a potent inhibitor of insulin secretion and its effect is mediated via somatostatin receptor 5 (SSTR5) in the endocrine pancreas. To investigate the consequences of gene ablation of SSTR5 in the mouse pancreas, we have generated a mouse model in which the SSTR5 gene was specifically knocked down in the pancreatic beta cells (betaSSTR5Kd) using the Cre-lox system. Immunohistochemistry analysis showed that SSTR5 gene expression was absent in beta cells at three months of age. At the time of gene ablation, betaSSTR5Kd mice demonstrated glucose intolerance with lack of insulin response and significantly reduced serum insulin levels. Insulin tolerance test demonstrated a significant increase of insulin clearance in vivo at the same age. In vitro studies demonstrated an absence of response to SST-28 stimulation in the betaSSTR5Kd mouse islet, which was associated with a significantly reduced SST expression level in betaSSTR5Kd mice pancreata. In addition, betaSSTR5Kd mice had significantly reduced serum glucose levels and increased serum insulin levels at 12 months of age. Glucose tolerance test at an older age also indicated a persistently higher insulin level in betaSSTR5Kd mice. Further studies of betaSSTR5Kd mice had revealed elevated serum C-peptide levels at both 3 and 12 months of age, suggesting that these mice are capable of producing and releasing insulin to the periphery. These results support the hypothesis that SSTR5 plays a pivotal role in the regulation of insulin secretion in the mouse pancreas.