烟草品种、育苗方式和烟蚜来源对烟蚜茧蜂寄生能力的影响

【目的】本研究旨在筛选出适合烟蚜茧蜂Aphidius gifuensis寄生烟蚜Myzus persicae的烟草品种、育苗方式和烟蚜来源,为烟蚜茧蜂人工繁殖和复壮提供科学参考。【方法】采用盆栽法,调查了不同烟草品种(云烟87、K326、翠碧1号和红花大金元)繁殖烟蚜若蚜、不同来源烟蚜(来自烟区、来自非烟区和室内繁殖种群)若蚜和烟草不同育苗方式(土壤育苗和湿润育苗)繁殖烟蚜若蚜时,烟蚜茧蜂成蜂对烟蚜若蚜的寄生率以及成蜂羽化率、寿命、体型大小和雌蜂比。【结果】结果表明,不同烟草品种繁殖烟蚜若蚜对烟蚜茧蜂成蜂寄生率存在显著影响。其中,在红花大金元和翠碧1号繁殖烟蚜上的烟蚜茧蜂成蜂寄生率分别比在K326繁殖烟蚜上的烟蚜茧蜂成蜂寄生率高19.00%和14.00%,但对烟蚜茧蜂的其他指标没有显著影响;不同烟蚜来源对烟蚜茧蜂寄生率也存在显著影响,其中,烟蚜茧蜂成蜂对非烟区烟蚜若蚜和烟区烟蚜若蚜的寄生率比对室内繁殖种群烟蚜若蚜的寄生率分别高20.25%和16.75%,但对烟蚜茧蜂成蜂的羽化率、寿命、体型大小和雌蜂比没有显著影响;烟草不同育苗方式对烟蚜茧蜂成蜂的寄生率无显著影响。【结论】烟蚜茧蜂对烟蚜...     

几种因子对马尼拉侧沟茧蜂寄生效能的影响

马尼拉侧沟茧蜂Microplitis manilae是斜纹夜蛾Spodoptera litura的一种重要幼虫寄生蜂。本文以斜纹夜蛾2龄幼虫为寄主,在26±1℃、RH 65%±5%、L：D=12:12的人工气候箱内,研究生殖方式、雌蜂日龄、寄生时间段、雄蜂出现与否以及雄蜂密度等因子对其寄生效能的影响。结果表明：马尼拉侧沟茧蜂可营产雄孤雌生殖和两性生殖两种生殖方式,两种方式在亲代寄生率、子代羽化率和发育历期均无显著差异。随着雌蜂日龄的增加,其寄生率和子代性比显著降低,但子代发育历期随雌蜂日龄的增加而延长。马尼拉侧沟茧蜂在12:00-18:00时间段的寄生率、子代羽化率和性比最高,子代发育历期最短。当寄生蜂密度一定时,子代性比随着寄主密度的增加而显著增加;当寄主密度一定时,子代性比随着寄生蜂密度的增加而显著下降;雄蜂在场时,子代性比显著高于无雄蜂在场时。子代性比随着亲代雄蜂密度的增加而显著降低,但雄蜂密度对亲代寄生率,子代羽化率、发育历期无显著影响。     

保幼激素类似物对烟蚜茧蜂生长发育、寄生率和蜕皮相关酶活性的影响

【目的】烟蚜Myzus persicae是烟草上重要的害虫之一,烟蚜茧蜂Aphidius gifuensis是烟蚜的一种优势寄生蜂。本研究旨在筛选出可延迟烟蚜茧蜂羽化时间的最佳保幼激素,解决规模化繁殖过程中出现的烟蚜茧蜂羽化不一致、不整齐,生产上急需烟蚜茧蜂防控烟蚜时所需烟蚜茧蜂数量不足而影响防蚜效果等严重问题。【方法】利用液浸法测定了不同浓度(5 000, 1 000, 200, 40和8 ng/μL)的5种保幼激素类似物包括稀虫乙酯(ZR-512)、稀虫炔酯(ZR-777)、稀虫酯(ZR-515)、苯氧威［(对苯氧乙基)氨基甲酸乙酯)］和保幼激素Ⅲ(2,6-壬二烯酸)处理后对烟蚜茧蜂羽化率、羽化时间、成蜂寿命、雌蜂比例和寄生率的影响;通过生物化学方法测定1 000 ng/μL这5种保幼激素类似物处理后烟蚜茧蜂蛹内与蜕皮相关酶含量和活性,筛选能延迟烟蚜茧蜂羽化时间的最佳保幼激素类似物。【结果】测试的不同浓 度的5种保幼激素类似物中200 ng/μL ZR-777和1 000 ng/μL ZR-512处理后能显著延迟烟蚜茧蜂羽化时间,分别比对照(10%丙酮处理)延迟了44.00和56.00 h;不同浓度的ZR-515和苯氧威处理后烟蚜茧蜂羽化率较对照组显著降低。与对照组相比,测试的不同浓度的5种保幼激素类似物对成蜂寿命均没有显著影响;1 000和40 ng/μL ZR-777处理显著降低了雌蜂比例。200 ng/μL ZR-777, 1 000 ng/μL ZR-512和5 000 ng/μL ZR-512处理对烟蚜茧蜂的寄生率无显著影响。5种保幼激素类似物以1 000 ng/μL浓度处理时,ZR-512处理组中烟蚜茧蜂蛹内酚氧化酶含量和活性以及几丁质酶活性均最低。【结论】生产上可用1 000 ng/μL ZR-512和200 ng/μL ZR-777处理烟蚜茧蜂,以达到调控烟蚜茧蜂羽化时间,取得足量、一致的烟蚜茧蜂。结果为烟蚜茧蜂规模化繁殖提供了理论依据。     

杀虫剂对烟蚜茧蜂不同发育阶段的毒性

【背景】烟蚜茧蜂是控制烟蚜田间种群的重要寄生蜂。施用化学杀虫剂防治烟蚜及其他害虫时,也会对烟蚜茧蜂产生毒性,影响对烟蚜种群的自然控制效果。了解杀虫剂对烟蚜茧蜂不同发育阶段的毒性,可为田间选择合理施药时间提供参考。【方法】在室内用试管药膜法和饲喂法测定了5%阿维菌素、5%啶虫脒、10%顺式氯氰菊酯和10%吡虫啉对烟蚜茧蜂成蜂的毒性,并在烟蚜茧蜂各虫期使用亚致死浓度药剂处理,研究这些杀虫剂对其羽化的影响。【结果】阿维菌素的触杀和胃毒作用最强,烟蚜茧蜂24 h死亡率分别为87.78%和94.44%;吡虫啉的触杀和胃毒作用最弱,烟蚜茧蜂24 h死亡率分别为41.11%和61.11%;啶虫脒(烟蚜茧蜂24 h死亡率分别为81.11%和86.66%)、顺式氯氰菊酯(烟蚜茧蜂24 h死亡率分别为64.44%和67.78%)的触杀和胃毒作用居中。在寄生蜂卵期用药,阿维菌素和啶虫脒可显著降低当代成蜂羽化率;在幼虫期用药,4种杀虫剂均显著降低了成蜂的羽化率;在蛹期用药,4种杀虫剂对成蜂的羽化率均没有显著影响。在寄生蜂幼虫期使用阿维菌素会使雌蜂比例显著高于对照,其余3种杀虫剂对雌蜂比例均无显著影响。【结论与意义】在烟蚜茧蜂成虫期使用这些杀虫剂,死亡率均较高,因此在成蜂较多时应禁止使用杀虫剂。     

螟蛉盘绒茧蜂的过寄生行为及其对子代生长发育的影响

【目的】过寄生现象普遍存在于寄生蜂寄生过程中。本研究旨在探究螟蛉盘绒茧蜂Cotesia ruficrus的过寄生对子代发育的影响及影响过寄生行为的主要因素。【方法】室内研究了螟蛉盘绒茧蜂在其寄主稻纵卷叶螟Cnaphalocrocis medinalis3龄幼虫上过寄生行为的发生,不同产卵次数对寄主存活及子代蜂生长发育的影响,研究了不同接蜂时间和不同接蜂密度对过寄生发生的影响。【结果】螟蛉盘绒茧蜂存在过寄生行为,无论雌蜂有无产卵寄生经历,均能在被自身寄生过和同种不同个体寄生过的寄主内产卵。寄生蜂茧量随着被产卵次数的增加而增加,被产卵3~5次的寄主体内死亡的寄生蜂幼虫数随着增大。寄主在育出蜂前的死亡率随着被产卵寄生次数的增加而增加,被产卵5次时,寄主育出蜂前死亡率达50%。过寄生使螟蛉盘绒茧蜂子代蜂卵-蛹的历期延长,羽化率和雌雄性比下降,雌蜂体型随寄生次数的增加显著变小。过寄生率随着接蜂密度及接蜂时间的增加而增加。【结论】在寄主上产卵2次对螟蛉盘绒茧蜂子代发育是最适合的,产卵3次及以上为过寄生。过寄生使蜂子代发育适合度降低,不利于子代生长发育。在室内大量繁殖螟蛉盘绒茧蜂时,应减少接蜂密度和接蜂时间,从而减少过寄生的发生。     

冷藏米蛾卵对稻螟赤眼蜂和玉米螟赤眼蜂子代质量的影响

【目的】以稻螟赤眼蜂Trichogramma japonicum Ashmead和玉米螟赤眼蜂T.ostriniae为试验对象,研究低温冷藏米蛾卵对赤眼蜂子代质量的影响,为米蛾卵的合理利用,赤眼蜂的工厂化生产和应用提供理论依据。【方法】将米蛾卵在不同温度(1、4、7、10℃)下冷藏不同时间(3、5、7、10、15、20、25、30、40d),研究米蛾卵冷藏后作为寄主卵对两种赤眼蜂子代寄生卵量、F_2代羽化出蜂率和雌蜂率的影响,利用赤眼蜂子代寄生卵量、F_2代羽化出蜂率和雌蜂率三者乘积表示赤眼蜂子代质量(Q),根据赤眼蜂子代质量判断冷藏米蛾卵对子代质量的影响。【结果】米蛾卵冷藏温度和时间对赤眼蜂子代寄生卵量影响显著,但不同赤眼蜂种类和不同冷藏温度间表现不同。繁殖稻螟赤眼蜂时,米蛾卵在4℃下冷藏赤眼蜂寄生卵量下降最缓,米蛾卵冷藏20d内赤眼蜂寄生卵量与对照之间差异不显著,在其他温度下米蛾卵冷藏3 d稻螟赤眼蜂寄生卵量与对照之间差异达到显著水平;繁殖玉米螟赤眼蜂时,米蛾卵在4℃下冷藏赤眼蜂寄生卵量下降最缓,米蛾卵冷藏20d赤眼蜂寄生卵量与对照之间差异达到显著水平,1℃下冷藏赤眼蜂寄生卵量下降最快,米蛾卵冷藏5 d赤眼蜂寄生卵量与对照之间达到显著水平。米蛾卵冷藏对稻螟赤眼蜂和玉米螟赤眼蜂F_2代的羽化率和雌蜂率产生的不利影响相对较小,米蛾卵冷藏30 d赤眼蜂F_2代的羽化率仍在70%以上,雌蜂率仍在75%以上。【结论】米蛾卵冷藏超过一定的时间以后会对稻螟赤眼蜂和玉米螟赤眼蜂子代的寄生卵量,F_2代的羽化出蜂率和雌蜂率产生不利影响,从而降低子代稻螟赤眼蜂和玉米螟赤眼蜂的质量,但在适宜的温度下冷藏一定时间内对其子代质量影响不显著,其中4℃下冷藏米蛾卵繁殖的赤眼蜂子代质量最佳,冷藏30 d赤眼蜂子代质量降低不到50%。     

光周期和温湿度对烟蚜茧蜂寄生能力和繁殖的影响

【目的】烟蚜茧蜂Aphidius gifuensis对烟蚜Myzus persicae有着极高的寄生率,而被广泛用于烟田防治烟蚜。但在人工扩繁烟蚜茧蜂过程中,环境因素对烟蚜茧蜂的生长发育有一定影响。本研究旨在明确光周期、湿度和温度对烟蚜茧蜂在烟蚜上寄生力的影响。【方法】在室内分别调查温度25℃、相对湿度70%与4个光周期(9L∶15D,12L∶12D, 14L∶10D和19L∶5D)组合条件下,温度25℃、光周期14L∶10D与4个相对湿度(65%, 70%, 75%和80%)条件下,以及相对湿度70%、光周期14L∶10D与4个温度(10℃, 15℃, 25℃和35℃)组合条件下,烟蚜茧蜂成蜂对烟蚜若蚜的寄生率及成蜂羽化率、寿命、性比(雌性占比)和后足胫节长度。【结果】结果表明光照时间过长或过短均会对烟蚜茧蜂的生长发育造成负面影响。在温度25℃和相对湿度70%时,光周期14L∶10D下烟蚜茧蜂成蜂的体型最大,其成蜂后足胫节最长,为0.439 mm;光周期为12L∶12D下烟蚜茧蜂成蜂的体型最小,后足胫节长度只有0.345 mm;光周期14L∶10D下烟蚜茧蜂成蜂对烟蚜若蚜的寄生率、寿...     

班氏跳小蜂对新寄主资源的寄生适合度

【目的】班氏跳小蜂Aenasius bambawalei是扶桑绵粉蚧Phenacoccus solenopsis的伴迁性天敌,迄今已知该寄生蜂只能寄生扶桑绵粉蚧,但是我们发现该寄生蜂还能成功寄生另一种外来有害生物——石蒜绵粉蚧P. solani。本研究旨在明确班氏跳小蜂对该新寄主资源的寄生适合度,为今后充分开发、利用该寄生蜂提供科学依据。【方法】在实验室条件下,以马铃薯Solanum tuberosum块茎作为粉蚧的寄主植物,测定了班氏跳小蜂对不同龄期石蒜绵粉蚧的寄生适合度,并在非选择条件下测定了上述两种寄主上僵蚧形成时间以及该寄生蜂羽化时间、寿命、后足胫节长度、寄生率、羽化率及子代性比。【结果】班氏跳小蜂可寄生石蒜绵粉蚧的雌成虫及2龄和3龄若虫,但只有寄生雌成虫才能正常羽化出蜂。分别以石蒜绵粉蚧与扶桑绵粉蚧为寄主时,最适合的蜂蚧比分别为2∶15和2∶20。不同寄主对僵蚧形成时间及班氏跳小蜂的羽化时间无显著影响,但显著影响班氏跳小蜂的寿命以及雌蜂后足胫节长度,尤其是扶桑绵粉蚧上羽化的寄生蜂的寿命比以石蒜绵粉蚧上的长约20 d。而且,班氏跳小蜂对扶桑绵粉蚧的寄生率(54.0%)显著高于对石蒜绵粉蚧的(25.3%),但班氏跳小蜂在这两种寄主上的羽化率均在90%以上,差异不显著;寄生扶桑绵粉蚧的雌蜂比例高于寄生石蒜绵粉蚧的雌蜂比例。【结论】班氏跳小蜂能寄生石蒜绵粉蚧,且只在雌成虫上完成世代发育;与在更适寄主扶桑绵粉蚧上比较,石蒜绵粉蚧上羽化的班氏跳小蜂在寿命及雌蜂个体大小上有劣势。     

烟蚜茧蜂寄生对烟蚜生长发育和繁殖的影响

【目的】为探究烟蚜茧蜂Aphidius gifuensis对烟蚜Myzus persicae寄生后烟蚜生长发育和繁殖影响及其在烟蚜防控中的作用。【方法】采用室内叶片培养皿法,测定了不同龄期烟蚜(1-4龄若蚜及成蚜)被烟蚜茧蜂寄生后烟蚜当代(F₀)及后代(F₁)的发育历期、寿命、产仔量。【结果】烟蚜1龄若蚜被烟蚜茧蜂寄生后,1龄若蚜历期受到显著影响,较未被寄生对照缩短了0.65 d (33.00%),而2-4龄若蚜期和成蚜历期未受显著影响;2龄若蚜被寄生后,4龄若蚜和成蚜历期均受到显著影响,较未被寄生的对照分别缩短了1.50 d (100.00%)和0.83 d (100.00%),而2和3龄若蚜期未受显著影响;3龄若蚜被寄生后,4龄若蚜和成蚜期均受到显著影响,较未被寄生对照分别缩短了1.50 d (100.00%)和0.83 d (100.00%),而3龄若蚜期未受显著影响。2龄若蚜被寄生后烟蚜的寿命和产仔量均受到显著影响,寿命较未被寄生对照缩短了8.39 d(54.00%),每雌产仔量较未被寄生对照减少了48.67头(100.00%)。此外,2-3龄若蚜被寄生后其后代(F₁)1龄若蚜历期受影响最大,较未被寄生烟蚜后代1龄若蚜期缩短了0.80 d(40.00%),其F₁代平均寿命较未被寄生烟蚜后代平均寿命延长了5.72 d(41.20%),但其产仔量与对照差异不显著。【结论】不同龄期烟蚜被烟蚜茧蜂寄生后,其发育历期和寿命比未被寄生的缩短,产仔量比被未寄生的少,但其F₁代平均寿命比未被寄生后代烟蚜的长且其产仔量未受显著影响。当代2龄若蚜期是控制烟蚜增长的关键时期。这些结果对确定烟蚜茧蜂防治烟蚜适期及认识其机理具有重要参考意义。     

斑痣悬茧蜂在黏虫寄主体内与中红侧沟茧蜂竞争下的存活和发育表现

【目的】不同种寄生蜂在同一小生境中可能寄生同一共享寄主。本研究旨在为认识寄生蜂种间互作关系,并为科学评价寄生性天敌控害效应提供依据。【方法】在室内以单寄生性斑痣悬茧蜂Meteorus pulchricornis(Wesmael)和中红侧沟茧蜂Microplitis mediator(Halidy)及其寄主黏虫Mythimna separata(Walker)低龄幼虫为材料,以寄生顺序和间隔时间为因素进行种间寄生竞争效应实验,观察比较两种蜂的存活和斑痣悬茧蜂子代的发育历期、体型大小和寿命等发育参数。【结果】不同寄生顺序和间隔时间组合处理下斑痣悬茧蜂子代蜂存活率始终高于中红侧沟茧蜂,且先寄生的斑痣悬茧蜂子代存活率高于后寄生的蜂,提前24 h寄生的斑痣悬茧蜂子代存活率可高达96.7%。当斑痣悬茧蜂先于中红侧沟茧蜂寄生时,其子代幼虫发育历期比单独寄生(对照)时显著延长;当后于中红侧沟茧蜂寄生时,其子代幼虫发育历期与单独寄生时无显著差异。各竞争处理下,斑痣悬茧蜂子代成虫寿命均长于单独寄生的子代成虫;子代成虫后足胫节长度与单独寄生相比明显缩短。【结论】结果说明,斑痣悬茧蜂在黏虫低龄幼虫体内与中红侧沟茧蜂的竞争中占有优势,但竞争对斑痣悬茧蜂子代生长发育具有负面影响。     

Effects of high temperatures recorded during diapause completion ofTrichogramma brassicae prepupae (Hym.: Trichogrammatidae), on the treated generation and its progeny

Trichogramma brassicae Bezdenko (Hym., Trichogrammatidae) is a parasitoid used for controlling the European corn borer,Ostrinia nubilalis Hübner (Lep., Pyralidae). In parts of south-eastern France, the parasitoids may be placed under a shelter when they are in the prepupal stage for diapause termination, before they are released among the crops. High temperatures (31°C–32°C) can occur during this period. Prepupae were exposed to one or two high temperature shocks at 32°C in the laboratory, and the effects of these shocks were then recorded on a number of biological parameters of the parasitoids belonging to the experimental generation Go and to the progeny generation G1. The emergence rate of Go individuals was highly affected, even when the prepupae had been exposed to a single shock. This decreased the number of parasitoids, in addition to reducing the fecundity of the females. The temperature shocks also affected the emergence rate of generation G₁. No changes were observed regarding the other parameters (minimum duration of final pupal development, longevity, proportion of females). A temperature shock, even a short-lasting low amplitude one, may thus have strong implications on the efficiency of the parasitoids.     

Cold‐induced expression of diapause in Praon volucre: fitness cost and morpho‐physiological characterization

Cold exposure (2°C for 7 days) in constant darkness at mummy stage induces diapause expression in 9% of the Praon volucre Haliday population. Diapausing parasitoids show a significant delay in emergence time compared with nondiapausing counterparts. A diapause‐mediated polyphenism is observed in mummy colour, with diapausing mummies being clearly darker than nondiapausing ones. The diapause status of dark mummies is confirmed by a significant reduction in metabolic rate. Diapausing parasitoids also display specific morphological characteristics: they are heavier (fresh and dry mass) and accumulate larger fat reserves than nondiapausing counterparts. The diapause status is associated with a fitness cost in terms of adult longevity. There is no evidence of diapause‐related change in supercooling ability.     

家蝇蛹和果蝇蛹繁育的蝇蛹金小蜂对果蝇蛹的寄生比较

【目的】蝇蛹金小蜂Pachycrepoideus vindemmiae(Rondani)是杨梅园等果园果蝇类害虫蛹期常见寄生蜂种类,在对果蝇类害虫的生物防治上具有重要价值。本文旨在探讨使用家蝇蝇蛹为替代寄主繁育蝇蛹金小蜂的方法。【方法】探讨分别以家蝇蛹和果蝇蛹繁育的蝇蛹金小蜂对家蝇和果蝇蝇蛹的选择性,并比较了在两种寄主上繁育的蝇蛹金小蜂在大小、寿命、产卵期、后代产量和性比等方面的差异。【结果】结果表明与果蝇蛹相比,家蝇蛹明显较大,在家蝇蛹上发育的蝇蛹金小蜂后代个体也明显较大;家蝇蛹和果蝇蛹发育的寄生蜂雌蜂寿命为(13.4±4.11)和(3.94±2.49)d、产卵期分别为(11.4±4.11)和(3.13±2.42)d、单头雌蜂后代雌蜂数量分别为(34.31±31.83)和(7.88±3.58)头,在家蝇蛹上繁育的寄生蜂明显具有较长的寿命和产卵期、更多的雌雄蜂后代数量;在对家蝇蛹和果蝇蛹的选择上,繁育自家蝇和果蝇的蝇蛹金小蜂雌蜂选择频率的差异不大。【结论】利用家蝇蛹繁殖的蝇蛹金小蜂在寄生果蝇蛹时具有更大优势,在繁殖蝇蛹金小蜂控制杨梅园等果蝇的为害时,可以选择家蝇蛹作为替代寄主。     

松毛虫赤眼蜂滞育诱导及解除条件研究

【目的】以柞蚕Antheraea pernyi卵为繁殖寄主,对松毛虫赤眼蜂Trichogramma dendrolim滞育诱导及解除条件进行研究,以解决赤眼蜂工厂化生产和大面积应用中面临的的中、长期储存问题。【方法】通过观测不同发育阶段(寄生柞蚕卵在26℃培养40、96和144 h)、滞育诱导温度(10、13和16℃)和诱导时间对松毛虫赤眼蜂滞育的影响,确定松毛虫赤眼蜂滞育诱导条件;通过观测滞育诱导温度和滞育后的贮藏温度对滞育解除的影响,确定松毛虫赤眼蜂滞育解除条件。【结果】在松毛虫赤眼蜂的不同发育阶段对其进行持续的低温刺激均能使其导入滞育,但以小幼阶段(26℃培养40 h)开始效果最佳,寄生卵在26℃培养40 h后,转入10℃和13℃下连续诱导31 d,滞育率可达100%和99.12%。滞育诱导温度和滞育后的贮藏温度对松毛虫赤眼蜂解除滞育所需时间和解除滞育后的羽化出蜂率有较大影响,10℃诱导滞育后置于1℃冷藏的赤眼蜂解除滞育所需时间最短,解除滞育后的羽化出蜂率和单卵出蜂数更高,更耐储存。此条件下冷藏约30 d开始打破滞育,在正常发育下温度下羽化出蜂,60 d羽化出蜂率达到95.24%,冷藏4个月后羽化出蜂率仍在60%以上,单卵出蜂数高于50头。【结论】松毛虫赤眼蜂最佳滞育诱导条件为26℃培养40 h后,转入10℃连续低温诱导31 d;最佳滞育解除条件为1℃低温储存,但储存期不能超过4个月。     

Storage techniques of mummies and adults of Aphidius gifuensis

Technology for mass storage is one of the most important issues facing the use of parasitoids for biological control programmes. The emergence rate, the proportion of females, adult longevity, parasitism rate of Aphidius gifuensis after cold storage of mummies at 5°C for different time periods, and the effect of different diets on their longevity were assessed. The results indicated that 10–30 days was a suitable period for cold storage at 5°C, but that 20 days was optimal. The 5% glucose solution was a successful food supplement for A. gifuensis. These results are important to the commercial exploitation of this economically important parasitic wasp.     

Rapid cold hardening in the predatory mite Euseius (Amblyseius) finlandicus (Acari: Phytoseiidae)

A rapid cold hardening response was studied in diapause and non-diapause females of the predatory mite Euseius finlandicus. When laboratory reared diapause and non-diapause females were transferred and maintained from the rearing temperature of 20 degrees C for 2 h to -11.5 degrees C and -10 degrees C, 10 to 20% survived respectively. However, conditioning of diapause females for 4 h at a range of temperatures from 0 to 10 degrees C before their exposure for 2 h to -11.5 degrees C, increased survival to approximately 90%. Similarly, conditioning of non-diapause females for 4 h at 5 degrees C before their exposure for 2 h to -10 degrees C increased survival to 90%. A similar rapid cold hardening response in both diapause and non-diapause females was also induced through gradual cooling of the mites, at a rate of approximately 0.4 degrees C per min. The rapid increase in cold tolerance after prior conditioning of the mites to low temperatures, was rapidly lost when they returned to a higher temperature of 20 degrees C. Rapid cold hardening extended the survival time of diapause and non-diapause females at sub-zero temperatures. The cost of rapid cold hardening in reproductive potential after diapause termination was negligible. In non-diapause females, however, the increase in cold tolerance gained through gradual cooling could not prevent cold shock injuries, as both fecundity and survival were reduced.     

Selection for non-diapause inAmblyseius cucumeris andAmblyseius barkeri and exploration of the effectiveness of selected strains for thrips control

In Europe and North America the western flower thrips,Frankliniella occidentalis, is an important pest in various greenhouse crops, such as sweet pepper and cucumber. Two species of predatory mite are commercially applied for biological control of this pest:Amblyseius cucumeris andA. barkeri. Thrips control is generally successful from March onwards. During winter, however, thrips control by these predatory mites is less effective. An important reason for this is that the commercially applied strains of both mite species enter reproductive diapause under short-day photoperiods, whereas the western flower thrips does not enter diapause. In this paper we report on selection experiments for non-diapause in strains of both mite species, aimed at obtaining predators that do not enter diapause under light- and temperature conditions prevailing in winter. Additional experiments were done to estimate the potential of the selected lines as control agents ofF. occidentalis. Selection for non-diapause proved highly successful in both predatory mite species. In a New Zealand strain ofA. cucumeris diapause incidence decreased from 41% to 0% in about ten generations; in a Dutch strain ofA. barkeri diapause incidence decreased from 67% to 0% in about six generations. Furthermore, selection for non-diapause had no influence on predator performance, measured as predation rate and oviposition rate on a diet of first instar thirps larvae. Rates of predation and oviposition were the same for selected and unselected lines in both species; rates of predation and oviposition were higher forA. cucumeris than forA. barkeri. After 18 months under non-diapause conditions, no less than 92% of a sample of the selected non-diapause line ofA. cucumeris did not enter diapause when tested under diapause-inducing conditions. This indicates that ‘non-diapause’ is a stable trait in these predatory mites. Finally, a small-scale greenhouse experiment in a sweet pepper crop showed that the selected non-diapause line ofA. cucumeris established successfully under diapause-inducing short-day conditions.     

Cyanoprotein: Quantitative changes and synthesis in diapause and juvenile hormone analog treated bean bug,Riptortus clavatus

Quantitative changes of cyanoproteins (CPs) in diapause and juvenile hormone (JH) analog treated bean bug, Riptortus clavatus, were analyzed by rocket immunoelectrophoresis (RIE). In diapause-oriented nymphal females and males, CP-A (CP-1, 2 and 3) and CP-B (CP-4) increased and reached a maximum level just before nymphal-adult ecdysis, which was the same in non-diapause female and male nymphs. Both CP-A and B disappeared immediately after adult emergence. After this initial decline CP-4 appeared again in the hemolymph, followed after a few days by CP-1, 2 and 3. CP-A and B then increased slowly but constantly in both diapause female and male adults. Both diapause females and males at day 30 after adult emergence had large amounts of CP-A (CP-1, 2 and 3) and CP-B (CP-4). Treatment of diapause females (day 30) with methoprene induced only CP-1 synthesis and increased CP-A content about twice in both the whole body and the hemolymph, but did not effect on CP-B content. Methoprene treated females developed ovaries which accumulated yolk containing CPegg and vitellin (Vn). In diapause males treated with methoprene CP-A and B were not induced and decreased gradully in concentration, eventually disappearing completely, similar to post-diapause males (30 days after transferred to long day condition) in which CPs were not detected. These results show that methoprene treatment of diapause females and males induced the same dynamical situations of CP-A and B seen in non-diapause adults, i.e. only CP-A was induced in females and CPs disappeared in males. This suggests that CP synthesis is regulated by juvenile hormone.     

引进花角蚜小蜂成虫的寿命和羽化节律

通过室内饲养和连续观察,研究了食物、温度对引进花角蚜小蜂成虫寿命的影响及其羽化的时间节律.结果表明：食物对该寄生蜂成虫寿命有极显著影响,喂食20％蜂蜜或20％蜂蜜＋新鲜松针可将雌虫寿命从不喂食的1.5 d延长到14.8 d和17.3 d,将雄虫寿命从不喂食的1.5 d延长到11.3 d和12.3 d.喂食20％蜂蜜条件下,温度也表现出极显著影响,23 ℃和26 ℃下雌、雄成虫的寿命均明显较长,32 ℃下均最短,相同温度下雌虫的寿命显著长于雄虫.日周期中,雌虫主要在11:00-15:00羽化,18:00以后基本不羽化;雄虫主要在9:00-12:00羽化,17:00以后基本不羽化.在花角蚜小蜂的主要羽化期7-9月,7月羽化量最大 ,此后8、9月呈波浪式递减;单日羽化的成虫中,雌虫大多占80％以上,雄虫则长期在一个较低水平波动.对比试验发现,花角蚜小蜂在收蜂棚中的出蜂量比在收蜂箱中更大.花角蚜小蜂在羽化前积累的能量十分有限,人工放蜂前提供必要的营养补充将有助于提高生物防治效果.福建和广东夏季的高温、花角蚜小蜂雌成虫和松突圆蚧雌成蚧虫口高峰期不吻合、极高的雌性比例等是影响该寄生蜂种群稳定的潜在因素.收蜂棚有利于大量收集花角蚜小蜂,适合在生产上应用.