椰心叶甲蛹寄生蜂——椰心叶甲啮小蜂的生物学特性

椰心叶甲啮小蜂Tetrastichus brontispae Ferrière是椰心叶甲Brontispa longissima（Gestro）蛹的重要内寄生蜂,2004年从台湾引入到海南。在实验室条件下,对椰心叶甲啮小蜂的形态、行为、发育、存活、繁殖等生物学特性进行了观察研究。结果表明,雌蜂个体比雄蜂大,腹部明显可见产卵器。每头寄主蛹出蜂量平均为21.5头,其中雌蜂约占77.4%。椰心叶甲啮小蜂羽化不久即能交配,交配时间约为1～2 min。椰心叶甲啮小蜂的产卵高峰期在交配后的24 h内,且产卵量受温度的影响较大; 蜂蜜、蔗糖、葡萄糖均能有效地延长其成虫的寿命,并能提高其怀卵量和寄生率,其中以取食蜂蜜的效果最好。该蜂发育、存活和繁殖的适宜温度为20℃～28℃,低于16℃或高于30℃对其存活不利。利用16℃、20℃、24℃、28℃、30℃下的发育历期和有效积温公式计算出椰心叶甲啮小蜂的发育起点温度（C）为9.6℃,有效积温（K）为324.9日·度。     

低温贮存对椰心叶甲啮小蜂品质的影响

研究低温贮存椰心叶甲蛹Brontispa longissima(Gestro)和椰心叶甲僵蛹对椰心叶甲啮小蜂Tetrastichus brontispae Ferriere种群品质的影响。寄生10℃低温贮存1~4日龄椰心叶甲蛹结果表明,1日龄椰心叶甲蛹的寄生率、羽化率、出蜂率、单蛹出蜂数、后代寄生能力均优于其他日龄,其次为2、3日龄的椰心叶甲蛹,最差为4日龄的椰心叶甲蛹。1日龄椰心叶甲蛹在10℃下贮存5,10,15,20d后,上述生物学指标和种群参数均随贮存天数增加而降低,其中以5d和10d的净生殖率、内禀增长率和周限增长率较未经低温贮存的差异小。1~11日龄椰心叶甲僵蛹于10℃贮存10d的结果表明,8日龄椰心叶甲僵蛹的雌蜂寿命、羽化率、单蛹出蜂数、寄生能力均优于其他日龄僵蛹。8日龄椰心叶甲僵蛹在10℃下贮存5,10,15,20d后,上述生物学指标和种群参数均随贮存天数增加而显著低于对照。     

椰心叶甲啮小蜂触角感觉器的扫描电镜观察

应用扫描电镜(SEM)对椰心叶甲啮小蜂Tetrastichus brontispae Ferrière成虫触角感器的超微结构进行观察。结果表明,在触角上共有8种感器,分别为毛形感器、多孔板状感器、刺形感器、锥形感器、耳形感器、乳状感器、腔形感器和Bhm氏鬃毛;其中毛形感器和板形感器是主要感器,数量较多分布较广;雌雄蜂触角有明显的性二型现象,表现为雌雄触角大小不同,触角感器类型、大小、数量、分布不同。     

椰心叶甲啮小蜂(Tetrastichus brontispae)实验种群生命表的编制

通过解剖椰心叶甲被寄生僵虫统计椰心叶甲啮小蜂未成熟期的发育历期、存活率与生殖力数据,编制了椰心叶甲啮小蜂的实验种群生命表.常温下椰心叶甲啮小蜂卵、幼虫和蛹的历期分别为3.1、5.0 d和9.3 d,啮出前期为2.1 d.卵、幼虫和蛹的存活率分别为0.9184、0.9521和0.9818,椰心叶甲啮小蜂的成虫羽化率为0.9,单雌产卵量为23.78粒,种群趋势指数为12 45.通过此生命表的组建,讨论了生命表中种群趋势指数(I)与生殖力表中净增殖力(R0)的关系,认为这两个概念本为同一含义,应该合并.此外,在成虫寿命大于等于2d的情况下,成虫逐日存活率与逐日产卵概率乘积的和小于1,且成虫寿命越长其值越小,结果导致在不考察成虫逐日存活率与逐日产卵概率的情况下种群趋势指数被严重高估,因此组建任何形式的生命表都应考察并计入成虫逐日存活率与逐日产卵概率.     

椰心叶甲啮小蜂发育起点温度和有效积温研究

椰心叶甲啮小蜂Tetrastichus brontispae Ferriere在实验室内,相对湿度75±5%,光周期L:D=12:12,温度16℃,20℃,24℃,28℃条件下,世代平均历期分别为53.7天,28.0天,21.2天,16.2天.其卯、幼虫、蛹及整个世代的发育起始点温度分别为13.15±0.49℃,10.25±0.44℃,12.41±0.57℃,10.50±0.89℃;有效积温分别为15.35±0.76日度,107.21±3.76日度,113.60±6.22日度,281.50±7.05日度.椰心叶甲啮小蜂生长发育历期随温度的升高而缩短,与温度的关系符合指数函数:y=226.19667e-0.096991x.     

椰扁甲啮小蜂寄生对椰心叶甲蛹免疫反应的影响

为了测明椰扁甲啮小蜂Tetrastichus brontispae寄生对寄主椰心叶甲Brontispa longissima蛹的血细胞和体液免疫反应的影响,开展了椰扁甲啮小蜂寄生对椰心叶甲蛹血细胞数量和延展性、血淋巴酚氧化酶活性、血淋巴黑化百分率和血细胞凝集素活性等影响的研究。结果表明：与同期未被寄生蛹相比,寄生蛹血细胞总量在寄生后2 d显著降低,但寄生后4 d显著升高; 寄生蛹的浆血细胞延展率在寄生后2 d显著降低,寄生后4 d显著升高;寄生蛹的血淋巴黑化百分率在寄生后0.5～2 d较高,寄生后3～4 d降低直至为0;寄生蛹的血淋巴酚氧化酶活性在寄生后0.5 d,1 d和4 d时显著升高;寄生蛹的血凝素活性在寄生后2 d较高,寄生后1 d和4 d较低。结果说明椰扁甲啮小蜂寄生使寄主椰心叶甲蛹血细胞和体液免疫反应呈现不规律的变化。     

入侵害虫椰心叶甲的研究进展

近30年来,椰心叶甲Brontispa longissima(Gestro)在亚太椰子产区扩散蔓延,成为棕榈植物上主要害虫。2002年,该害虫入侵我国海南并暴发成灾。化学防除是控制椰心叶甲危害的首要措施,其中包括挂药包等农药缓释技术,而生物防治是控制该虫扩散蔓延的经济有效措施。从感病椰心叶甲虫体上分离的微生物杀虫剂绿僵菌Metarhizium anisopliae被我国和其他多个国家应用。椰心叶甲天敌寄生蜂的引进利用是可持续控制该害虫发生的重要措施。幼虫寄生蜂椰甲截脉姬小蜂Asecodes hispinarum和蛹寄生蜂椰心叶甲啮小蜂Tetrastichus brontispae是椰心叶甲的两种重要天敌。2004年,椰甲截脉姬小蜂和椰心叶甲啮小蜂被引入到我国,经扩繁释放后,取得了良好的控害效果,其中有些地区的椰甲截脉姬小蜂寄生率可达90%,椰心叶甲啮小蜂寄生率可达100%。连续放蜂,且椰心叶甲种群有合适虫龄被寄生蜂寄生是控害效果的关键。气候等生态因子也可能是影响寄生蜂控制靶标害虫效果的因素,应进一步加强研究。论文最后提出了未来椰心叶甲防控的研究的方向。     

椰扁甲啮小蜂寄生后椰心叶甲蛹血淋巴蛋白质双向电泳图谱分析

分析昆虫被寄生蜂寄生后血淋巴蛋白质组分及组分含量变化,从蛋白质水平分析寄生蜂寄生引起寄主昆虫的生理变化,有利于探索寄生蜂调控寄主的机理。以椰心叶甲Brontispa longissima和椰扁甲啮小蜂Tetrastichus brontispae为研究材料,采用蛋白质双向电泳技术及图像分析技术分析了椰心叶甲蛹被椰扁甲啮小蜂寄生后不同时期血淋巴蛋白质图谱及其变化情况。结果表明:寄生后0.5, 1, 2, 3和4 d,被寄生蛹血淋巴共检测到的蛋白斑点数分别为982, 926, 712, 636和680个,其中特异性蛋白斑点的数量分别为650, 400, 336, 229和150个;同期未被寄生蛹血淋巴共检测到的到的蛋白斑点数分别为645, 817, 640, 873和940个,其中特异性蛋白斑点的数量分别为313, 291, 264, 466和410个;被寄生蛹和同期未被寄生蛹能匹配的蛋白斑点分别为332, 526, 376, 407和530对。被寄生蛹血淋巴蛋白斑点数量的异常变化表明寄主的生理功能受到了严重的影响。     

低温胁迫下椰心叶甲啮小蜂正反向消减cDNA文库的构建及其序列分析

【背景】椰心叶甲啮小蜂在防治椰心叶甲危害上取得了重要成果,其耐低温胁迫能力将决定该寄生蜂是否能在低温环境下建立种群并发挥控害效能。筛选椰心叶甲啮小蜂低温胁迫下相关响应基因,可为揭示其耐寒性机理提供重要线索。【方法】采用抑制消减杂交技术,分别以经0℃处理24 h后的试虫与未经低温处理的试虫c DNA互为tester与driver,正反向构建椰心叶甲啮小蜂c DNA消减文库,经蓝、白斑筛选,鉴定阳性差异片段,并分别随机挑选正反向文库224和119个阳性克隆进行序列比对分析。【结果】本试验所构建的c DNA消减文库为椰心叶甲啮小蜂低温胁迫下特异表达的c DNA消减文库;经蓝、白斑筛选,分别得到了40和4个高质量ESTs,经PCR鉴定插入片段长度主要分布于200~700 bp之间;序列分析结果表明,差异表达基因的功能主要涉及新陈代谢、细胞结构、信号传导、氨基酸和蛋白质合成的生理过程,并筛选出5类与啮小蜂耐寒性相关的基因,包括Hsp家族蛋白、海藻糖磷酸合酶、谷氨酰胺合成酶、ATP合成酶β亚基和NADH脱氢酶。【结论与意义】该研究对进一步研究椰心叶甲啮小蜂抗寒性状的表达具有一定的参考价值,为揭示啮小蜂抗低温耐寒机制打下一定的理论基础。     

椰心叶甲啮小蜂复眼和触角在交配中的作用及其超微结构的扫描电镜观察

对寄生蜂交配行为的了解将有助于发展对其行为调控的技术,提高寄生蜂对害虫控制的效能。为探讨椰心叶甲啮小蜂Tetrastichus brontispae Ferrière的复眼和触角在交配中的作用,用水溶性黑色素和液体石蜡分别涂抹该蜂复眼和触角后观察其交配行为,并利用扫描电镜（SEM）观察其复眼和触角的超微结构,分析雌、雄蜂触角感器的分布与数量差异。结果表明：椰心叶甲啮小蜂雄蜂的复眼在交配过程中起重要作用,雌蜂复眼作用不显著。在椰心叶甲啮小蜂求偶识别和接受过程中,雄蜂触角柄节部位起主要作用,其次是棒节部位,再次是鞭节的索亚节部位,而雌蜂触角鞭节索亚节部位起主要作用,然后是棒节部位,最后是柄节部位。扫描电镜观察表明椰心叶甲啮小蜂触角上共有8种感器,其中毛形感器和板形感器是主要感器,雌、雄蜂触角有明显的性二型现象,表现为触角大小不同及触角感器类型、大小、数量、分布不同。     

Biological assessment of Tetrastichus brontispae,a pupal parasitoid of coconut leaf beetle Brontispa longissima

To control coconut leaf beetle, Brontispa longissima (Gestro), the pupal parasitoid Tetrastichus brontispae Ferrière was imported from Taiwan and its biology was studied in quarantine in Hainan, China. The parasitoid development includes an egg, three larval instars and three pupal stages. Its developmental time from egg to adult was 19.5±0.5 days under conditions of 24±2°C and 75±5% relative humidity (RH). Temperature had no effect on the sex ratio of offspring, but significantly affected the parasitism rate and reproduction. The parasitism rates were 98.07, 97.97 and 95.03% at 28, 24 and 20°C, respectively, whereas the parasitism rate was 52.18% at 18°C and 69.48% at 30°C, respectively. Furthermore, the parasitoids reared at 18 and 30°C produced fewer offspring than those at 20, 24 and 28°C, respectively. With the increase in temperature, developmental time decreased linearly from 46.19 days at 18°C to 17.10 days at 28°C. RH significantly influenced development, parasitism rate and the reproduction of T. brontispa. With the decrease of RH, developmental time increased from 22.94 days at 20% RH to 18.84 days at 95% RH. In contrast, parasitism rate and the number of offspring per female increased with the increase of RH. Though emergence rates between 50 and 95% RH were much higher than those between 20 and 35% RH, the sex ratios between 20 and 95% RH were not different. Photoperiod had no effect on parasitism, the number of offspring per female, emergence and the sex ratio of T. brontispae, but developmental time was significantly different for different photoperiods. Sucrose, honey and glucose significantly enhanced adult longevity, parasitism and the number of offspring per female of T. brontispae, but had no effect on the sex ratio and survival. Females of T. brontispae only parasitized fourth to fifth larval instars and 1–5-day-old pupae, but there was a significant difference in the number of offspring per female, development time, emergence and the sex ratio of offspring in different instars. These results showed that 1-day-old pupae, a temperature of 24–28°C and 65–95% RH were optimal for T. brontispae. These findings should be helpful in developing a production system to rear and release T. brontispae in large enough quantities to effectively control coconut leaf beetle.     

啮小蜂雌蜂接受寄主线索的探讨

啮小蜂Tetrastichussp.是一种群聚性的蛹内寄生蜂,主要寄生茶长卷叶蛾Homona magnanima的蛹,实验室中亦能寄生亚洲玉米螟Ostrinia furnacalis的蛹。研究了速冻寄主蛹、视觉和嗅觉线索在啮小蜂寄主接受中的作用,实验结果表明,速冻寄主蛹对啮小蜂接受寄主的影响不大,啮小蜂雌蜂主要是通过嗅觉线索接受寄主的,而视觉在寄主接受过程中仅起辅助作用。     

Plant reproductive biology of herbaceous monocots in a Venezuelan tropical cloud forest

The reproductive biology of 29 herbaceous understory monocot species was studied in a tropical cloud forest of northern coastal Venezuela (Henri Pittier National Park). Of the 23 plant species, 6 (26.1%) were self-incompatible and 17 (73.9%) self-compatible, the latter consisting of 12 (52.2%) fully self-compatible and 5 (21.7%) partially self-compatible species. An analysis of sexual systems and temporal variation of sex expression showed that of 29 monocot species, 14 (48.3%) were hermaphrodite and adichogamous, 14 (48.3%) monoecious and dichogamous, and one (3.4%) dioecious. The combination of monoecy and dichogamy prevented autogamy in 11 (91.7%) of the 12 self-compatible and monoecious species; one (8.3%) was autogamous. Of all species, 24 (82.8%) were obligate outbreeders, 2 (6.9%) spontaneously autogamous, and 3 (10.3%) partially autogamous. Ovule and flower abortion were not significantly different between the different groups. Pollen-ovule ratio was significantly different between monoecious and hermaphrodite species. The number of pollen grains and ovules per flower and the pollen-ovule ratio were variable among various pollination types. The average pollen-ovule ratio was higher in beetle-, dipteran-, and wind-pollinated species than in bee-, bird-, and bat-pollinated species. The first three pollination types were restricted to monoecious species, and the second three groups were restricted to hermaphrodite species. Of 33 plant species investigated, 12 (36.4%) displayed vegetative reproduction. The reproductive features of the understory monocot species are discussed in the context of life form, devices of cross-pollination, and geological history of the tropical cloud forest.