稻田飞虱卵寄生蜂群落结构和动态的初步研究

报道了广东省四会市大沙镇稻田中褐飞虱Nilaparvata lugens卵期寄生蜂的结构和动态。该群落由缨小蜂科和赤眼蜂科的6个属、共19种卵寄生蜂组成。其中,稻虱缨小蜂Anagrus nilaparvatae、长管稻虱缨小蜂A. longitubulosus和拟稻虱缨小蜂A. paranilaparvatae是群落中的优势种群,它们对控制褐飞虱种群卵期的存活率起主要作用。6个属在群落中的优势地位相对稳定,但不同物种包括优势种类在群落中的地位并不稳定。早、晚稻前期,群落的寄生蜂数量与稻田褐飞虱数量正相关;中期,寄生蜂数量在一定的范围内波动;后期,其数量先上升,然后急剧下降。水稻生长前、中和后期,寄生蜂对褐飞虱卵的平均寄生率分别约为76%,70%和50%。     

不同营养源对稻虱缨小蜂寿命及寄生能力的影响

研究了蜂蜜、玉米花粉、大豆花、褐飞虱蜜露和黄脊飞虱蜜露对稻虱缨小蜂寿命、寄生能力以及寄生行为对稻虱缨小蜂寿命和存活率的影响。结果表明,蜂蜜、玉米花粉、褐飞虱蜜露和大豆花均能明显延长稻虱缨小蜂的寿命。并且显著地提高了对褐飞虱卵的寄生能力,其中蜂蜜最有效,大豆花次之,玉米花粉和褐飞虱蜜露这两种营养源以玉米花粉(水和褐飞虱蜜露+水的形式)对提高稻虱缨小蜂寿命最有效,而单一玉米花粉、花粉液、褐飞虱蜜露稀释液和纯褐飞虱蜜露均不能延长稻虱缨小蜂寿命,黄脊飞虱蜜露对稻虱缨小蜂的寿命和寄生能力均无影响。寄生行为对稻虱缨小蜂的寿命基本无影响。但致使其40～48h内的存活率提高,此后的存活率降低较快,在稻田周围的作物和植被上调查到约10种飞虱,非稻田生境能为稻田寄生性天敌提供寄主和食物,是理想的庇护所,对保护和提高稻田天敌种群数量,提高稻田天敌的生物控制作用。     

两种稻虱缨小蜂种群生态的比较

在南京市郊和我国南方稻区,寄生稻飞虱卵的缨小蜂主要是稻虱缨小蜂Anagrus nilaparvatae Pang et wang和拟稻虱缨小蜂A.paranilaprvatae Pang et Wang两个种.这两个种在田间的种群消长,呈明显“此起彼落”的季节性交替.作者以比较生态学方法探讨了产生这一现象的原因.夏季30℃以上高温对稻虱缨小蜂未成熟期的存活和雌虫产卵有明显抑制作用,但拟稻虱缨小蜂具有耐高温能力.稻虱缨小蜂和拟稻虱缨小蜂种群增长的理论最适温度分别为27.41℃和31.87℃,最适温度下的种群内禀增长力以稻虱缨小蜂为高.当供以白背飞虱和褐飞虱卵时,拟稻虱缨小蜂只寄生褐飞虱卵,稻虱缨小蜂对褐飞虱卵也有明显的喜好.两种缨小蜂对褐飞虱卵密度的功能反应均符合Holling Ⅱ型.     

稻虱缨小蜂(Anagrus nilaparvatae)在两种稻飞虱上的生殖力及其应用潜能

利用寄生变红卵和仔代成蜂数量作为繁殖力估计等方法,编制了稻虱缨小蜂(Anagrus nilaparvatae pang and wang)在褐飞虱(Nilaparvata lugens (St(a)l))卵和白背飞虱(Sogatella furcifera (Horvath))卵上繁殖的实验种群生命表,测定了稻虱缨小蜂寄生褐飞虱和白背飞虱的生殖力,分析了稻虱缨小蜂对稻飞虱卵的寄生能力.结果表明:在相同的繁蜂条件下,稻虱缨小蜂寄生褐飞虱卵的净生殖力R0为10.26,内禀增长率rm为0.2213,平均单雌产仔数为14.52头;寄生白背飞虱卵的净生殖力R0为8.78,内禀增长率rm为0.1840,平均单雌产仔数为12.20头.两组生命表参数比较分析显示褐飞虱卵具有较强的室内繁蜂潜能,可利用其进行室内繁蜂.应用稻虱缨小蜂、褐飞虱及白背飞虱的生命表参数讨论了稻虱缨小蜂在稻飞虱生物防治中的应用潜能及其可能的利用途径.     

稻虱缨小蜂的寄主选择性和适宜性

稻虱缨小蜂Anagrus nilaparvatae Pang &Wang对白背飞虱Sogatella furcifera(HO· rvath)卵龄无明显的寄生选择性,但在新鲜寄主中的发育历期较短,育出的蜂体较大,生殖力较高,而羽化 率和雌雄性比则不受寄主卵龄的影响。在白背飞虱和褐飞虱Nilaparvata lugens (Stal)卵共存时,稻虱缨小蜂明显选择褐飞虱。稻虱缨小蜂在褐飞虱卵中的发育显著地比在白背飞虱卵中的慢;褐飞虱卵育出的 蜂的初羽化成虫怀卵量显著高于白背飞虱卯育出的,虫体大小也类似,且虫体越大,生殖力越高。从白背飞虱卵育出的蜂供给白背飞虱卵(W→W)时,产卵量低于其它育蜂寄主和供给产卵寄主组合(w→B、B→B、B→W)的,其内禀增长力rm较其余者小25%。本文还讨论了应用适宜性指数来综合衡量寄主的适宜性。     

水稻品种对稻虱缨小蜂发育、存活及繁殖的影响

水稻品种既能直接地经物理结构,亦能间接地通过改变褐飞虱Niladarvatalugens(Stal)卵的适宜性,影响稻虱缨小蜂Anagrus nilaparvatae Pang et Wang的发育、存活和繁殖。稻虱缨小蜂的羽化率、怀卵量分别与其寄主褐飞虱卵所处水稻品种叶鞘鞘脊的硅细胞密度呈极显著和显著负相关;同时,怀卵量和虫体大小还与受水稻品种影响的褐飞虱卵粒大小呈极显著正相关。稻虱缨小蜂种群增长能力指数的组分分析表明,不同水稻品种影响稻虱缨小蜂种群增长能力的主要因子不同,显示了水稻品种对稻虱缨小蜂影响的多因子作用。     

不同生境源的稻飞虱卵寄生蜂对寄主的选择和寄生特眭

稻飞虱重要卵寄生蜂缨小蜂Anagrus flaveolus、A optabilis和寡索赤眼蜂Oligosita aesopi、O.Naias均能在稻田和稻田周围的非稻田生境中生存。而.Ftaveolus为优势种。不同生境来源的卵寄生蜂有着不同的寄生和选择特性。缨小蜂A.Flaveolus能在飞虱科内转换寄主,但需1～2代的适应期。寄主卵对寡索赤眼蜂O.Aesopi的寄生有较大的影响,用褐飞虱和黑尾叶蝉诱集的O.Aesopi呼;不能交叉寄生。稻田内诱集的寄生蜂选择稻飞虱,而杂草地中诱集的缨小蜂则对飞虱T.Pusanus有一定的选择性。非稻田生境对保护稻飞虱卵寄生蜂有很大的作用,但对其寄生特性有较大的影响。     

二种稻虱缨小蜂空间寄生习性的观察

观察结果:拟稻虱缨小蜂喜选择寄生稻株中上部叶位和分蘖枝组织内的褐飞虱卵;稻虱缨小蜂喜选择寄生稻株下部叶位组织内灰飞虱、白背飞虱卵及主茎枝组织内白背飞虱卵和分蘖枝组织内灰飞虱卵。二种稻虱缨小蜂均表现喜选择寄生叶片组织内寄主的习性。这一空间寄生习性的表现,本文从稻株空间温度对缨小蜂寄生活动的影响及寄主产卵部位、稻株组织结构等方面进行了综合分析和讨论。     

水稻品种和稻虱缨小蜂对褐飞虱协同作用的模拟分析

利用我们先前的试验结果和文献资料,组建了水稻品种－褐飞虱－稻虱缨小蜂３者相互关系的模拟模型．模拟分析表明水稻品种能直接和间接地通过物理或化学特性影响稻虱缨小蜂的寄生作用,其中以影响褐飞虱卵垂直分布型、稻虱缨小蜂的迁入时间、未成熟期历期和怀印量等的水稻品种特性起主要作用．同时,模拟分析还表明中等抗性的水稻品种,配以增强稻虱缨小蜂寄生作用的品种特性,就能有效地控制褐飞虱的危害．文中还就协调水稻品种抗性与天敌协同控制褐飞虱的途径进行了讨论．     

稻田稻飞虱卵寄生蜂群落的重建和维持

研究了综防区和非综防区稻田飞虱卵寄生蜂群落的重建和维持。结果表明：早稻生长期,稻虱缨小蜂Anagrus nilaparvatae 和拟稻虱缨小蜂 A. paranilaparvatae 在水稻移栽后第9天进入综防区稻田,在第13天进入非综防区稻田,同在第21天完成群落重建,重建速率分别是0.28种/天和0.21种/天。晚稻生长期,综防区和非综防区稻虱缨小蜂和拟稻虱缨小蜂均在水稻移植后第1天进田,至第21天完成群落重建,重建速率分别是0.12种/天和0.04种/天。维持阶段综防区群落较非综防区稳定。群落重建和维持受温度、种库中卵寄生蜂种类和数量、种库距稻田的远近、稻田中害虫种类和数量以及害虫防治策略的影响。     

稻虱缨小蜂对褐飞虱和白背飞虱卵的识别机制

研究了室内条件下信息化合物及稻飞虱卵的形态特征在稻虱缨小蜂识别2种卵寄主褐飞虱和白背飞虱中的作用。结果表明,褐飞虱和白背飞虱雌成虫诱导的水稻挥发物对稻虱缨小蜂的引诱作用无显著差异,各自的引诱比例(头数)分别为57.50%(23头)和42.50%(17头)。稻虱缨小蜂对2种飞虱4组材料,完整卵、磨碎卵、带卵叶鞘和若虫为害叶鞘的行为反应,除了在褐飞虱完整卵上的搜索时间极显著地长于在白背飞虱完整卵上的以外,其余的均不存在差异。挥发物捕集结果表明,褐飞虱和白背飞虱雌成虫诱导的水稻挥发物组成相非常一致。上述结果表明水稻挥发物、稻飞虱利它素及飞虱卵的形态特征在稻虱缨小蜂识别褐飞虱和白背飞虱卵中的作用不明显。文中就稻虱缨小蜂识别2种寄主的机制进行了讨论。     

Preference and performance of Anagrus nilaparvatae (Hymenoptera: Mymaridae): effect of infestation duration and density by Nilaparvata lugens (Homoptera: Delphacidae)

The effect of Nilaparvata lugens (St?l) infestation duration and density on the host preference and performance of Anagrus nilaparvatae Pang et Wang, an egg parasitoid of rice planthoppers, was determined. The results showed that the parasitoid preferred N. lugens eggs on the plants infested with 10 gravid N. lugens females for 1 d to those plants infested with 10 gravid females for 2 or 3 d. It was also found to prefer N. lugens eggs on plants infested with 10 or 20 adult females after 24 h of infestation to those plants infested with 5 or 80 females. The parasitoid's offsprings had lower survival rates, fecundities, female ratios, indexes of capacity for population increase, and longer developmental durations on plants when they were infested with high N. lugens density (80 adult females per plant). However, the performance of the parasitoid on plants infested with low N. lugens density (5 female adults per plant) was similar to those on plants with intermediate N. lugens density (10 or 20 adult females per plant). Low preference of the parasitoid for N. lugens eggs on plants with heavy or light infestation levels may be correlated with low host suitability and detectability, respectively. The result implies an important role of herbivore-induced rice volatiles in the host preference of the parasitoid A. nilaparvatae, by which the parasitoid perceives the host and its suitability.     

Multi-generation effects of Bt rice on Anagrus nilaparvatae, a parasitoid of the nontarget pest Nilapavarta lugens

Little is known about the potential cumulative long-term effects of transgenic crops on nontarget organisms. In the present laboratory study, the potential cumulative effects of transgenic Bacillus thuringiensis (Bt) rice on parasitoids in successive generations were observed for an egg parasitoid, Anagrus nilaparvatae parasitizing eggs of Nilaparvata lugens (St?l) (Hemiptera: Delphacidae) feeding on Bt rice. Enzyme-linked immunosorbent assay test confirmed that Cry1Ab insecticidal protein could be detected in newly eclosed parasitoid adults. However, no significant effect on the fecundity of Anagrus nilaparvatae Pang et Wang (Hymenoptera: Mymaridae) was observed between Bt and non-Bt rice. Developmental times of both genders of A. nilaparvatae parasitizing host eggs laid in Bt (KMD1 and KMD2) rice lines were significantly prolonged from first generation to second generation, but not always prolonged from third generation to 11th generation as compared with the control rice line. Furthermore, the sex ratio of A. nilaparvatae progeny from the first generation to 11th generation in three rice lines was not significantly different. In general, our results suggested that the effect of Bt rice on this parasitoid could be negligible.     

水稻品种形态特征对稻虱缨小蜂功能反应的影响

在室内研究了水稻品种形态特征对褐飞虱卵在稻株上的分布以及由此而对稻虱缨小蜂功能反应的影响.结果表明,在所有测试品种中,褐飞虱卵在稻株上的垂直分布型可归为3类,即上中部为主分布型、中下部为主分布型和均匀分布型.稻株上、中、下各部位的褐飞虱卵量多少与其相应部位叶鞘鞘脊的相对高度呈极显着正相关.稻虱缨小蜂对上中部为主分布型褐飞虱卵(在浙农大40上)的功能反应明显地强于对中下部为主分布型的褐飞虱卵(在浙852上).     

New techniques of rearingAnagrus flaveolus [Hym.: Mymaridae], an egg parasitoid of the brown planthopper

A small cage was designed to study the biology and behavior ofAnagrus flaveolus Waterhouse, an important egg parasitoid of the brown planthopper,Nilaparvata lugens (Stal), a pest of rice. A method of rearing moderate numbers of parasitoids on planthopper eggs in the laboratory was developed. Though the mymaridAnagrus flaveolus Waterhouse, a common egg parasitoid of rice planthoppers and leafhoppers all over Asia, reduces pest populations, its biological control potential has largely been overlooked because of its minute size and the lack of suitable techniques to study and rear it in the laboratory.Ôtake (1968, 1969) described some techniques to study the development, longevity and fecundity of a related speciesAnagrus nr.flaveolus Waterhouse. The cages described herein are much simpler to build and more efficient to use compared with those developed earlier. Rearing this important parasitoid in large numbers in the laboratory has not been done before.     

水稻品种形态特征对稻虱缨小蜂功能反应的影响

在室内研究了水稻品种形态特征对褐飞虱卵在稻株上的分布以及由此而对稻虱缨小蜂功能反应的影响．结果表明,在所有测试品种中,褐飞虱卵在稻株上的垂直分布型可归为３类,即上中部为主分布型、中下部为主分布型和均匀分布型．稻株上、中、下各部位的褐飞虱卵量多少与其相应部位叶鞘鞘脊的相对高度呈极显著正相关．稻虱缨小蜂对上中部为主分布型褐飞虱卵（在浙农大４０上）的功能反应明显地强于对中下部为主分布型的褐飞虱卵（在浙８５２上）．