【作者】 S M Mizanur Rahman；

【导师】 吴孔明；

【作者基本信息】 中国农业科学院 ， 农业昆虫与害虫防治， 2014， 博士

【摘要】 遗常室茧蜂Peristenus relictus Ruthe (Hymenoptera:Braconidae)是一种单寄生、容性寄生蜂,其寄主范围较广,发生于中国长江和黄河流域的一种本地内寄生性寄生蜂。这种卵育型的若虫寄生蜂可孤雌生殖,与红颈常室茧蜂同为一个类群中的主要寄生蜂,寄生在造成中国多种农作物经济损失的重要害虫盲蝽体内。尽管在过去10年中,中国种植Bt棉花获得了巨大的收益,但大面积种植转Bt基因棉花同时导致了次要害虫的爆发,特别是在农作物上急剧减低了广谱性叶面杀虫剂的使用,致使多种盲蝽爆发发生。因此,该寄生蜂已作为一种生防天敌,通过大量释放来控制中国Bt棉花种植区中种群数量迅速增长的多种盲蝽。该寄生蜂已广泛分布于世界各地,并已知该蜂的生态学、发育和繁殖生物学。然而,为探讨大量释放该蜂的生物防治潜力,仍有一些生物学特性亟待研究。为构建一种高效益的大量繁殖体系,了解该蜂种群动态并根据盲蝽的发生情况有效地进行田间释放,在室内进行了评价其对苜蓿盲蝽的生物防治潜力。本博士论文研究了盲蝽的天敌——遗常室茧蜂以下3个方面的生物学：1)遗常室茧蜂在不同寄主和寄生蜂密度下的功能反应、种内干扰和性比分配模式遗常室茧蜂对苜蓿盲蝽功能反应属于Holling Ⅱ,其寄生率随着苜蓿盲蝽的密度增加而呈显著减少。即寄主密度和寄生率为反比。结果表明,寄生数随着寄主密度的增加而增加,直到接近该蜂的最大生殖潜能。种内干扰结果表明,随着若虫与寄生蜂的比例的降低(寄主若虫保持80头),显著减少被寄生的寄主数,当处理为1头寄生蜂时,单头蜂产生的子代数是处理为16头寄生蜂时的20-30倍。干扰常数为1.20,存在着强烈的干扰作用。减少寄主比例并增加寄生蜂种个体数,明显增加了寄生蜂本身和种内其它个体的过寄生率,其后代雄性比例增加,这说明了寄生蜂之间存在强烈的种内竞争。寄主和寄生蜂密度之间的相互作用所反映的性比,充分支持了本地雄蜂竞争(LMC)理论假设。2)遗常室茧蜂对苜蓿盲蝽不同寄主龄期的偏好性以及发育和繁殖适应性寄主偏好及其适应性研究表明,该蜂主要偏好于1-3龄的苜蓿盲蝽若虫。在非选择性试验中,对1-2龄若虫的最高寄生率89.26%-91.09%,在选择性试验中为93.08-93.21%。然而,被寄生的1龄若虫的死亡率高于其它龄期被寄生若虫。重寄生率随着寄主龄期增加而减少。尽管1-4龄寄主若虫都能够被寄生,但2龄寄主若虫是最佳的寄生龄期,因为它产生的后代数量最多且雌性偏多。其次是3龄若虫,是寄主适应性的第二选择。5龄若虫被寄生后没有产出寄生蜂后代。寄主龄期越大寄生蜂羽化越快。3)不同恒温条件下寄生于苜蓿盲蝽的遗常室茧蜂的繁殖生物学温度是寄生蜂最关键的非生物影响因子之一,温度对寄生蜂的生殖力、产卵期、寿命、日产卵量以及总产卵量都有显著的影响。寄生蜂的寿命随着温度从15℃上升到30℃而缩短。雌蜂平均寿命从15℃时的28.40±1.29天下降到30℃时的7.20+0.66天,然而日平均产卵量在25℃时最高,为41.51±6.05粒,15℃时最低,为11.47+3.31粒。生殖寿命在20℃时最长,能产卵18.60±1.86天。20℃下产卵能力最高,为675.4±56.78粒卵,其次为25℃,为530.60±34.50粒卵。同时,寄生蜂的总寄生数与和产卵量趋势相同,20℃时寄生数591.20±2.87头若虫,15℃时的寄生数为217.80±3.61头若虫。本论文的结果表明遗常室茧蜂可作为防治在国Bt棉田中盲蝽的一种有效生物防治天敌。为了达到在Bt棉田上释放大量的寄生蜂的目的,大规模群繁中最佳的寄生蜂与寄主若虫比例应为1：80,并且最佳饲养温度为20℃。目标害虫2龄若虫时,是田间释放遗常室茧蜂最佳龄期。更多还原

【Abstract】 Peristenus relictus Ruthe (Hymenoptera:Braconidae) is a solitary, koinobiont, generalist (polyphagous), indigenous endoprasitoid identified from Yangtze and Yellow river regions of China. This synovigenic, nymphal, arrhenotokus parasitoid is a dominant member of the parasitoid guild along with P. spretus which parasitizes readily a wide range of economically important mirid bug (Hemiptera:Miridae) pests in its native range. Despite the huge gains from Bt cotton in China during the last decade, a large-scale adoption of transgenic Bt cotton has led to the outbreak of secondary pests, especially different mirid bugs due to a drastic reduction of broad-spectrum foliar insecticides on this crop. Therefore, P. relictus is being taking into consideration to use for augmentative releases as a potential candidate of biological control agent against rapidly growing population of different mirid species in Bt cotton habitats of China. It has been widely distributed across the world and much is known of its ecology, developmental and reproductive biology. However, some attributes to elucidate its biological potential for augmentative releases are yet to be exploited.With the aim of designing an effective and profitable mass-rearing system, understanding the population dynamics and developing an effective field releases program of this parasitoid with the phenology of mirids, laboratory experiments were conducted to evaluate its biological potential by using alfalfa plant bug, Adelphocoris lineolatus Goeze as host. This doctoral dissertation examined the potential of P. relictus as a biological control agent of mirid bugs through studies on three following aspects of P. relictus biology: 1) Functional response, mutual interference and sex allocation pattern of P. relictus to varying host and parasitoid densitiesP. relictus exhibited a Holling’s disc Type Ⅱ functional responses, meaning that the parasitism rate decreased exponentially with the increase in A. lineolatus density. In other words, an inverse relationship was established between host density and proportion of host parasitized. It was indicated that parasitism increased with the increment of host density until parasitoid reached its upper asymptote of reproductive potential. In terms of mutual interference, the decreased nymph-wasp ratio (by offering constant80hosts) significantly reduced the number of host parasitized and the number of progeny produced per parasitoid by20and30folds, respectively, at16parasitoids group as compared to single parasitoid. The interference constant (m) was estimated at1.20indicating a strong mutual interference. The scarcity of proportion of hosts and increased co-presence of conspecifics led to the significant increase of self-and conspecific superparasitism and male-biased sex ratio in the offspring population which explains the strong intraspecific competition amongst the foraging parasitoids. The interactive effects of host and parasitoid density reflected to the observed sex ratios to be in broad agreement with the predictions of local mate competition (LMC) theory.2) The preference and suitability of different host instars of A. lineolatus for the development and reproduction of P. relictusThe relative preference indices from host preference and suitability studies revealed that preference was mostly concentrated towards first to third instar nymphs of A. lineolatus. The highest parasitization was occurred in the early instar hosts (first and second) ranging from89.26to91.09%in no-choice tests; and93.21to93.08%in choice tests. However, first instar was the most susceptible to oviposition-induced mortality than all later-instar nymphs. Superparasitism decreased with the progress to later host-instar. Although first to fourth instar hosts were able to reproduce, second instar was the most suitable host stage in terms of highest progeny production and more female-biased sex allocation. Third instar was the second line of options for host suitability. Fifth instar did not yield any progeny. The later the host instar at parasitism, the faster the parasitoids emerged from host instar.3) Effect of varying constant temperatures on reproductive biology of P. relictus attacking A. lineolatus.Temperature is one of the key abiotic factors on the parasitoid’s reproductive potential. Oviposition period, longevity, daily oviposition and lifetime fecundity were significantly affected by temperature. Longevity shortened as the temperature increased from15to30℃. The average longevity of adult female parasitoids ranged from28.40±1.29d at15℃to7.20±0.66d at30℃while the daily mean oviposition was highest (41.51±6.05) at25℃and lowest (11.47±3.31) at15℃. Reproductive longevity was maximal at20℃with18.60±1.86days of oviposition. The highest potential lifetime fecundity was achieved at20℃with675.4±56.78eggs, which is followed by530.60±34.50eggs at25℃. Similarly, the total parasitism over lifetime followed the same trend as potential lifetime fecundity and ranged from591.20±52.87parasitized nymph at20℃to217.80±3.61nymphs at15℃.The outcomes of this dissertation research suggested that P. relictus has the potential to be an effective biological control agent of mirid bugs in Bt cotton fields of China. For the purpose of providing large number of wasps for augmentative releases into Bt cotton, the optimal parasitoid-nymph ratio for efficient mass-production system of P. relictus is1:80and the parasitoid should be reared on second instar of A. lineolatus at20℃. Second instar nymph is the best stage to target for effective control in field releases of P. relictus.更多还原