似士维螨实验种群的生殖力、性比率和世代期

Fecundity,sex ratio and generation time of laboratory populations of Schwiebea similis(Acari:Acaridae)

【目的】研究产卵时段和培养温度对似士维螨(Schwiebea similis Manson(蜱螨目:粉螨科))亲代雌螨生殖力、子代性比率和世代期的影响,为防治西洋参新害虫提供理论依据。【方法】采用二因素试验设计,因素A为亲代雌螨群产卵时段,设3个水平,分别为每批34头亲代雌螨在夜间产卵12h(N12h)、白天产卵12h (D12h)、昼夜产卵24h(DN24h);因素B为培养温度(T),设9个水平,分别为11.0,12.0,14.9,17.7,21.0,23.7,27.1,30.0和33.0℃。将子代卵、幼螨和若螨用群体培养法培养,统计各有效组合内子代雌、雄螨数及世代期,计算亲代雌螨均殖数(PCR)、子代性比率和世代期均值(N),并使均值服从方差分析;计算世代发育起点温度(C)和有效积温(K),并组建N与T间的倒数模型。【结果】亲代雌螨昼夜产卵,由此2时段内所产卵粒育活的子代成螨数近似,PCR均值间差异不显著(P>0.05)。在11.0～27.1℃,子代全螨PCR均值达13.9头/d,而在23.7℃最高为16.2头/d。产卵时段和培养温度对子代雌雄性比率都无显著影响(P>0.05),均值1.10,有波动但无定向偏差。培养温度对子代成螨世代期的影响极显著(P<0.01),世代期随温度的上升而骤降。子代全螨世代期N与温度T间的倒数模型为:N=K/(T-C)=(184.3±4.55)/[T-(8.43±0.28)];估算此螨在当地发生6～9代/年。【结论】昼夜节律不影响似士维螨的产卵习性,亲代雌螨均殖数显示其有高产特例,子代雌雄性比率反映其种群结构,而倒数模型揭示其生理学时期,并为估算其田间种群增长趋势提供基本参数。

【Objective】Impacts of both ovipositional period and rearing temperature on fecundity of parental females,filial sex ratio and generation time of the root mite Schwiebea similis Manson(Acari:Acaridae)were studied to provide theoretical basis for control of the new pest on American ginseng Panax quinquefolium L.【Method】A two-factor experiment design was adopted,factor A was ovipositional period of parental females with 3 levels,in that a batch of 34 parental females was allowed to lay eggs at night for 12 hours(N12h),in daytime for 12 hrs(D12h),and in a whole day for 24 hrs(DN24h),respectively;Factor B was rearing temperature(T)with 9 gradients,at 11.0,12.0,14.9,17.7,21.0,23.7,27.1,30.0 and 33.0℃respectively.Filial eggs,larvae and nymphs were reared colonially.Numbers of filial females and males were counted and their generation time from egg to adult was measured in each valid combination.Per capita reproduction(PCR)of parental females,filial sex ratio of female to male,and filial mean generation time(N)were calculated,and means were subjected to an ANOVA.Threshold temperature(C)and thermal constant(K)of filial adult mites were calculated,and 3 reciprocal models between N and T were then established.【Result】Parental females laid eggs day and night,and their fecundities in the 2 periods were similar,without significant difference at P>0.05.PCR averaged as high as 13.9 filial mites a whole day in the range from 11.0 to 27.1℃,and their peak was 16.2 filial mites at 23.7℃.Both ovipositional period and rearing temperature had no significant impact on filial sex ratios,and the mean was 1.10,fluctuating slightly without directional drift.Rearing temperature influenced generation time of the filial adults significantly at P<0.01,and N decreased sharply with T.The reciprocal model for N of all the filial adult mites on T was(m±SE):N=K/(T-C)=(184.3±4.55)/[T-(8.43±0.28)],and theoretical generations of the mite were estimated 6 to 9 a year when occurring in local areas.【Conclusion】The rhythm of day and night does not influence ovipositional behavior of S.similis.The PCR values indicate a special example for higher reproduction by the parental females tested.The sex ratios reflect the mode of its populations.The reciprocal models built herein reveal physiological time of the mite,and have provided some basic parameters for estimation of its population growth trends in the field.