Spatial and temporal variability in host use by Helicoverpa zea as measured by analyses of stable carbon isotope ratios and gossypol residues
Spatial and temporal variability in host use by Helicoverpa zea as measured by analyses of stable carbon isotope ratios and gossypol residues
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DOI：
10.1111/j.1365-2664.2010.01796.x
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发表时间：
2010-06-01
影响因子：
5.7
通讯作者：
Voth, Richard
中科院分区：
文献类型：
--
作者：
Head, Graham;Jackson, Ryan E.;Voth, Richard
P > 1。美国采用了高剂量/避难策略来管理转基因Bt棉花棉铃虫（CBW）、玉米螺旋虫（Boddie）等目标害虫对苏云金芽孢杆菌（Bt）的抗性风险。由非Bt棉花组成的结构避难已成为该策略的强制性组成部分，以产生与Bt作物昆虫在时间和空间上同步的非选择昆虫，通过交配稀释Bt抗性等位基因。然而，棉铃虫是高度多食性的，与Bt棉花同时利用大量的作物和杂草寄主。2002年和2003年期间，在美国五个主要产棉州进行了一项研究，利用棉铃虫蛾中13C与12C的比例来估计源自C(3)或C(4)植物的种群比例。一项独立的研究在2005年和2006年测量了来自四个州的蛾的棉酚残留量，从而能够识别出出生寄主是棉花而不是其他C(3)寄主的蛾。从6月中下旬到9月上旬，C(4)寄主是棉铃虫蛾的主要来源，这取决于各州。从8月下旬/ 9月初开始，持续1 ~ 4周，大部分飞蛾表现出C(3)寄主的同位素组成特征。然而，在此期间，在C(4)寄主上发育成幼虫的蛾的最低百分比通常为25%。到9月中旬和10月至11月，棉铃虫的大部分种群显示出C(4)同位素组成。在6月下旬至8月初期间，所有州棉铃虫蛾（带有棉酚残留物的蛾）的比例均低于1%，在北卡罗莱纳州整个季节均低于这一水平。在其他州，棉花来源的飞蛾在8月初至9月初期间增加，达到峰值，平均占所有飞蛾的1%。合成与应用。利用13C/12C比值和棉酚残留量的数据来评估非Bt棉花避难所对玉米抗Bt风险管理的重要性。每周对棉铃虫在棉花和C(3)植株上繁殖的估计表明，在整个季节，棉田附近的信息素诱捕器捕获的大部分棉铃虫蛾都没有在棉花上发育成幼虫。这一结果表明，在管理美国棉花带CBW种群对Bt棉花的潜在抗性方面，诸如使用结构化棉花避难所等棉花管理措施将发挥相对较小的作用——特别是与玉米相比。
P>1. A high dose/refuge strategy has been adopted in the USA to manage the risk of Bacillus thuringiensis (Bt) resistance in target pests such as the cotton bollworm (CBW), Helicoverpa zea (Boddie) in transgenic Bt cotton Gossypium hirsutum L. Structured refuges, consisting of non-Bt cotton, have been a mandated part of this strategy to produce non-selected insects that are temporally and spatially synchronous with insects from the Bt crop, diluting Bt resistance alleles through mating. However, the bollworm is highly polyphagous and exploits a large number of crop and weedy hosts concurrently with Bt cotton.2. A study was carried out in five major US cotton-producing states during 2002 and 2003 using the ratios of 13C to 12C in bollworm moths to estimate the proportions of the population originating from C(3) or C(4) plants. A separate study measured gossypol residues in moths from four states in 2005 and 2006, enabling the identification of moths whose natal hosts were cotton rather than other C(3) hosts.3. C(4) hosts served as the principal source of bollworm moths from mid-to-late June to early September, depending on the state. Beginning in late August/early September and lasting 1-4 weeks, the majority of moths exhibited isotopic compositions characteristic of C(3) hosts. During this period, however, the minimum percentage of moths that developed as larvae on C(4) hosts was typically > 25%. By mid-September and through October and November, the majority of the bollworm population exhibited C(4) isotopic compositions.4. Between late June and early August, cotton-derived bollworm moths (moths with gossypol residues) comprised < 1% of moths in all states, and remained below this level throughout the season in North Carolina. In other states, cotton-derived moths increased between early August and early September to peak at an average of 19 center dot 1% of all moths.5. Synthesis and applications. Data on 13C/12C ratios and gossypol residues in CBW moths were used to assess the importance of structured non-Bt cotton refuges for the management of Bt resistance risk in H. zea. Weekly estimates of bollworm breeding on cotton, C(3) plants other than cotton and C(4) plants showed that, throughout the season, the majority of bollworm moths caught in pheromone traps adjacent to cotton fields did not develop as larvae on cotton. This result implies that management practices in cotton such as the use of structured cotton refuges will play a relatively minor role - particularly compared with maize Zea mays L. - in managing potential resistance to Bt cotton in populations of the CBW in the US Cotton Belt.