Landscape effects of transgenic cotton on non-target ants and beetles

Transgenic crops producing toxins from Bacillus thuringiensis (Bt) can be planted in the same field for many years, and many insects exploiting such crops must disperse to other habitats to persist. Accordingly, effects of transgenic crop farming could accumulate through time and affect insect populations across agricultural landscapes. We monitored the population density of seven ant genera and beetle families and of rare ants and beetles in 84 non-cultivated sites abutting agricultural fields in Central Arizona. We assessed the short-term (during planting year) and long-term (over 5–6 years) landscape effect of farming Cry1Ac cotton on ant and beetle density in non-cultivated sites, in addition to several local and regional variables. Landscape variables (e.g., sequence of crops planted in neighbouring fields, crop diversity, and abundance) were more frequently associated with insect density than local variables (e.g., plant productivity and diversity in non-cultivated sites). In the short-term, use of Bt relative to non-Bt cotton in neighbouring fields was positively associated with density of one ant and two beetle groups in non-cultivated sites. However, acreage of Bt cotton located within 1 km from non-cultivated sites had more negative effects than acreage of non-Bt cotton on density of one ant and one beetle group. In the long-term, the proportion of years that Bt cotton was planted in neighbouring fields was positively associated with ant density but not beetle density. Results suggest that the farming of Bt cotton in neighbouring fields frequently resulted in positive short- and long-term landscape effects on ants and beetles in non-cultivated sites, while Bt cotton planted farther away had less frequent negative short-term impacts.     

Evolution of resistance to transgenic crops: interactions between insect movement and field distribution

The refuge strategy is designed to delay evolution of pest resistance to transgenic crops producing Bacillus thuringiensis Berliner (Bt) toxins. Movement of insects between Bt crops and refuges of non-Bt crops is essential for the refuge strategy because it increases chances that resistant adults mate with susceptible adults from refuges. Conclusions about optimal levels of movement for delaying resistance are not consistent among previous modeling studies. To clarify the effects of movement on resistance evolution, we analyzed simulations of a spatially explicit model based partly on the interaction of pink bollworm, Pectinophora gossypiella (Saunders), with Bt cotton. We examined resistance evolution as a function of insect movement under 12 sets of assumptions about the relative abundance of Bt cotton (50 and 75%), temporal distribution of Bt cotton and refuge fields (fixed, partial rotation, and full rotation), and spatial distribution of fields (random and uniform). The results show that interactions among the relative abundance and distribution of refuges and Bt cotton fields can alter the effects of movement on resistance evolution. The results also suggest that differences in conclusions among previous studies can be explained by differences in assumptions about the relative abundance and distribution of refuges and Bt crop fields. With fixed field locations and all Bt cotton fields adjacent to at least one refuge, resistance evolved slowest with low movement. However, low movement and fixed field locations favored rapid resistance evolution when some Bt crop fields were isolated from refuges. When refuges and Bt cotton fields were rotated to the opposite crop type each year, resistance evolved fastest with low movement. Nonrecessive inheritance of resistance caused rapid resistanceevolution regardless of movement rate. Confirming previous reports, results described here show that resistance can be delayed effectively by fixing field locations and distributing refuges uniformly to ensure that Bt crop fields are not isolated from refuges. However, rotating fields provided better insect control and reduced the need for insecticide sprays.     

Bt crop effects on functional guilds of non-target arthropods: a meta-analysis

Background

Uncertainty persists over the environmental effects of genetically-engineered crops that produce the insecticidal Cry proteins of Bacillus thuringiensis (Bt). We performed meta-analyses on a modified public database to synthesize current knowledge about the effects of Bt cotton, maize and potato on the abundance and interactions of arthropod non-target functional guilds.

Methodology/Principal Findings

We compared the abundance of predators, parasitoids, omnivores, detritivores and herbivores under scenarios in which neither, only the non-Bt crops, or both Bt and non-Bt crops received insecticide treatments. Predators were less abundant in Bt cotton compared to unsprayed non-Bt controls. As expected, fewer specialist parasitoids of the target pest occurred in Bt maize fields compared to unsprayed non-Bt controls, but no significant reduction was detected for other parasitoids. Numbers of predators and herbivores were higher in Bt crops compared to sprayed non-Bt controls, and type of insecticide influenced the magnitude of the difference. Omnivores and detritivores were more abundant in insecticide-treated controls and for the latter guild this was associated with reductions of their predators in sprayed non-Bt maize. No differences in abundance were found when both Bt and non-Bt crops were sprayed. Predator-to-prey ratios were unchanged by either Bt crops or the use of insecticides; ratios were higher in Bt maize relative to the sprayed non-Bt control.

Conclusions/Significance

Overall, we find no uniform effects of Bt cotton, maize and potato on the functional guilds of non-target arthropods. Use of and type of insecticides influenced the magnitude and direction of effects; insecticde effects were much larger than those of Bt crops. These meta-analyses underscore the importance of using controls not only to isolate the effects of a Bt crop per se but also to reflect the replacement of existing agricultural practices. Results will provide researchers with information to design more robust experiments and will inform the decisions of diverse stakeholders regarding the safety of transgenic insecticidal crops.     

Astylus atromaculatus (Coleoptera: Melyridae): abundance and role in pollen dispersal in Bt and non-Bt cotton in South Africa

In South Africa, modified Bt (Cry1 Ac) cotton cultivars and organic ones coexist. This raises the question of the risk of dissemination of genetically modified (GM) pollen to non-GM crops by visiting insects. We inventoried the flower-visiting insects in Bt and non-Bt cotton fields of the South African Highveld region and investigated their role in pollen dispersal. Their diversity and abundance varied slightly among sites, with Astylus atromaculatus as the predominant insect on both Bt and non-Bt cotton flowers. The other major flower-visiting species were Apis mellifera and solitary Apidae. No differences were found in the abundance of each taxum between Bt and non-Bt cotton except for Scoliidae and Nitidulidae, which were scarce overall (<0.5%) but more abundant on the non-Bt flowers in the central area of the field at one site. The pollen load on A. atromaculatus was as high as on Apis mellifera. Cage tests showed that A. atromaculatus can pollinate female cotton plants by transferring pollen from male donor plants. In the field, the flight range of this insect was generally short (25 m), but it can occasionally reach up to 200 m or even more. This study therefore highlights that A. atromaculatus, commonly regarded as a pest, could be an unexpected but efficient pollinator. Because its population density can be high, this species could mediate unwanted cotton pollen flow when distances between coexiting fields are not sufficient.     

转基因抗虫棉花和玉米与节肢动物相关的生态安全性研究进展

转基因抗虫棉花和玉米自1996年商业化种植以来,已取得显著的经济、生态和社会效益。与其相关的生态安全性,特别是其对非靶标生物的影响及靶标害虫的抗性监测和治理已成为人们普遍关注的话题。本文在大量室内和田间评价工作的基础上,系统综述了国内外研究在该领域内取得的进展。结果表明： 由于Bt棉田和玉米田杀虫剂用量的减少,某些对Bt杀虫蛋白不敏感的非靶标植食害虫种群有上升的趋势; 现阶段生产上推广种植的Bt棉花和玉米花粉对家蚕、柞蚕和蜜蜂等经济昆虫以及帝王斑蝶是安全的。杀虫剂用量的减少,降低了对天敌的杀伤力,Bt田中捕食性天敌的种类和数量均显著高于常规施药田; 但Bt田内靶标害虫数量的减少和质量的降低,在一定程度上影响了寄生性天敌的种类和数量。Bt棉花和玉米的大面积种植对农田生态系统节肢动物群落结构无明显不利影响。靶标害虫田间抗性监测结果表明,无论在以大农场单一种植经营为主的发达国家如美国或澳大利亚,还是在以小农经营为主的多种寄主作物小规模交叉混合种植模式的发展中国家如中国或印度,田间并未出现10年前人们所关注和预测的靶标害虫种群抗性上升问题。究其原因,可能与发达国家严格执行了预防性的抗性治理对策及发展中国家独特的作物种植模式有关。尽管目前在田间尚未发现害虫对Bt作物产生抗性,但应用更多年份之后,害虫对Bt作物的抗性就很可能不是“是否”发生问题,而是“何时”发生的问题。因此,今后的研究重点应放在Bt棉花和玉米长期、大面积种植后,其对非靶标生物及靶标害虫抗性发展影响的长期生态效应上。     

新疆棉区转Bt基因棉对棉铃虫生物学的影响

棉铃虫Helicoverpaarmigera高龄幼虫取食转Bt基因棉花组织后 ,化蛹率、羽化率、蛹重、体长均有显著下降 ,在转Bt基因棉花上棉铃虫的取食行为也受到较大的影响 ,表现为取食次数明显减少、吐丝下垂次数明显增加 ;无论是转Bt基因棉花还是常规棉花 ,棉铃虫 3龄幼虫主要分布于繁殖器官上 ,在转Bt基因棉花各繁殖器官上的分布概率为 :花 >棉铃 >棉蕾 ,常规棉花上分布概率为 :棉蕾 >棉铃 >花 ;棉铃虫高龄幼虫取食转Bt基因棉花各组织 ,成虫羽化后产卵量、卵孵化率均有明显下降 ;在较低的棉铃虫虫口密度下 ,转Bt基因棉花对棉铃虫有一定的产卵排趋性。     

Feeding, oviposition and survival of Liriomyza trifolii (Diptera: Agromyzidae) on Bt and non-Bt cottons

The effects of Bt transgenic cottons (Bt-I expressing cry1Ac and Bt-II expressing cry1Ab and cry2Ab or cry1Ab and cry1Fa) and non-Bt cottons on feeding, oviposition and longevity of adults, and development and survival of Liriomyza trifolii larvae were studied under laboratory conditions; and infestation on four Bt and two non-Bt cotton traits were investigated under field conditions. Laboratory choice and no-choice tests showed that L. trifolii adults were capable of distinguishing between Bt cottons and non-Bt cottons. In a choice test on younger plants (4-5 leaves), the adults were found more often and made more feeding punctures (FP) on non-Bt cottons than on Bt cottons. On older plants (8-9 leaves), adults made the most FP on non-Bt cotton followed by those on Bt-II cottons and the least on Bt-I cotton. The females oviposited more eggs (6.7 eggs per leaf) on non-Bt cotton than on Bt-I (1.7 eggs per leaf) and Bt-II (0.8 eggs per leaf) cottons on younger plants and oviposited similar numbers of eggs (0.7-1.3 eggs per leaf) on non-Bt and Bt cottons on older plants. In a no-choice test, the females also fed more FP on non-Bt cottons than on Bt cottons on both younger and older plants. The females oviposited more eggs (15.6 eggs per leaf) on non-Bt cotton than on Bt-I (8.2 eggs per leaf) and Bt-II (6.5 eggs per leaf) cottons on younger plants and similar numbers of eggs (2.5-3.3 eggs per leaf) on non-Bt and Bt cottons on older plants. Larval and puparial survivals were not different among Bt and non-Bt cottons. The occurrence and damage of leafminers on cottons in the field showed that L. trifolii infested more plants and leaves and had more mines on non-Bt cotton than on Bt cottons.     

Leaf surface factors of transgenic Bt cotton associated with the feeding behaviors of cotton aphids: A case study on non-target effects

The present paper reports case study results of the risk assessment of transgenic Bt cotton on a non-target pest, cotton aphid, Aphis gossypii. Several types of techniques, i.e., electrical penetration graph (EPG), light and electron microscopy, bioassays and chemical analysis, were applied to investigate physical and chemical leaf factors of 2 transgenic Bt cotton lines (GK12 and GK19) and their pa-rental non-Bt cotton line (Simian3) associated with searching and feeding behaviors of cotton aphids on leaves or leaf extracts of cotton plants. EPG results showed that there were some differences among behaviors of cotton aphids on 2 Bt cotton and 1 non-Bt cotton lines. Cotton aphids performed similarly to leaf surface extracts from 3 cotton lines; and leaf surface chemicals, mainly volatiles and waxes, were almost identical in the components and concentrations among the cotton lines. However, three cotton lines were quite different from each other in the densities of certain kinds of covering trichomes. Therefore, the relationships between the physical characteristics and the searching behaviors of cotton aphids on the three cotton lines were constructed as the regression equations. Glandular trichomes and covering trichomes with 5 branches influenced the cotton aphids' searching behaviors effectively; and other trichomes with other branches affected aphids in varying ways. These results demonstrated that leaf surface physical factors of transgenic Bt cotton lines different from their parental non-Bt line could affect the penetration behaviors of non-target cotton aphids. Cotton aphids penetrate and feed more easily on two Bt cotton lines than on the non-Bt cotton line.     

Effects of proportion and configuration of Bacillus thuringiensis cotton on pest abundance, damage, and yield

Bacillus thuringiensis (Bt) transgenic cotton, Gossypium hirsutum L., kills several economically important pests, reducing injury and increasing yields. Refuges of non-Bt cotton are currently planted with Bt cotton in different designs to slow pest resistance evolution. To compare the effects of differences in Bt/non-Bt plant heterogeneity found in different refuge designs on square (flower bud) damage, abscissions, sap-feeding herbivore densities, and yield in cotton, four types of 24-row cotton plots were planted in 2001 and 2002: 1) seed mixtures of Bt and non-Bt varieties, 2) 12-row strips of Bt and non-Bt, 3) solid Bt, and 4) solid non-Bt. For both years cotton bollworm, Helicoverpa zea (Boddie), damage was less in solid Bt plots than strips and mixtures and all were less than solid non-Bt plots. Cotton fleahopper, Pseudatomoscelis seriatus (Reuter), damage was affected by refuge, but only in 2002 when damage was greater in solid Bt plots than all other plots and greater in strips than solid non-Bt plots. Abscissions were least in solid non-Bt plots, and less in mixtures and strips than solid Bt plots. In 2001, western flower thrips, Frankliniella occidentalis (Pergande), density was greatest in mixtures, whereas sweetpotato whitefly, Bemisia tabaci (Gennadius), was greatest in solid Bt plots, and greater in mixtures than solid non-Bt plots. Yield also was affected by refuge, it was greater for solid Bt plots than for solid non-Bt plots and mixtures in 2001, but the reverse was true in 2002.     

The halo effect: suppression of pink bollworm on non-bt cotton by bt cotton in china

In some previously reported cases, transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt) have suppressed insect pests not only in fields planted with such crops, but also regionally on host plants that do not produce Bt toxins. Here we used 16 years of field data to determine if Bt cotton caused this "halo effect" against pink bollworm (Pectinophora gossypiella) in six provinces of the Yangtze River Valley of China. In this region, the percentage of cotton hectares planted with Bt cotton increased from 9% in 2000 to 94% in 2009 and 2010. We found that Bt cotton significantly decreased the population density of pink bollworm on non-Bt cotton, with net decreases of 91% for eggs and 95% for larvae on non-Bt cotton after 11 years of Bt cotton use. Insecticide sprays targeting pink bollworm and cotton bollworm (Helicoverpa armigera) decreased by 69%. Previously reported evidence of the early stages of evolution of pink bollworm resistance to Bt cotton in China has raised concerns that if unchecked, such resistance could eventually diminish or eliminate the benefits of Bt cotton. The results reported here suggest that it might be possible to find a percentage of Bt cotton lower than the current level that causes sufficient regional pest suppression and reduces the risk of resistance.     

Impact of different levels of non-Bt cotton refuges on pest populations,bollworm damage,and Bt cotton production

The impact of structured strip row refugia (varying from 10% to 50%) in the Bt cotton crops JKCH1947Bt (producing one toxin, Cry1Ac) and MRC7017BGII (producing two toxins, Cry1Ac and Cry2Ab) on the pest complex and cotton yield was studied. During the cropping season (June 2008 to November 2008), sucking pest incidence was negligible. However, the incidences of spotted bollworm, Earias vittella, and the leafroller, Sylepta derogata, were high on the non-Bt cotton. The total cotton seed yield of the Bt crop plus the refuge decreased proportionately with respect to the increase in proportion of non-Bt cotton. Total cotton production decreased significantly when 40% non-Bt cotton was planted as refuge. These studies showed that a refuge of up to 30% non-Bt cotton in JKCH1947Bt and up to 20% non-Bt cotton in MRC7017Bt did not affect total seed cotton yield compared to 100% Bt cotton.     

Increased frequency of pink bollworm resistance to Bt toxin Cry1Ac in China

Transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt) kill some key insect pests, but evolution of resistance by pests can reduce their efficacy. The main approach for delaying pest adaptation to Bt crops uses non-Bt host plants as "refuges" to increase survival of susceptible pests. To delay evolution of pest resistance to transgenic cotton producing Bt toxin Cry1Ac, the United States and some other countries have required refuges of non-Bt cotton, while farmers in China have relied on "natural" refuges of non-Bt host plants other than cotton. The "natural" refuge strategy focuses on cotton bollworm (Helicoverpa armigera), the primary target of Bt cotton in China that attacks many crops, but it does not apply to another major pest, pink bollworm (Pectinophora gossypiella), which feeds almost entirely on cotton in China. Here we report data showing field-evolved resistance to Cry1Ac by pink bollworm in the Yangtze River Valley of China. Laboratory bioassay data from 51 field-derived strains show that the susceptibility to Cry1Ac was significantly lower during 2008 to 2010 than 2005 to 2007. The percentage of field populations yielding one or more survivors at a diagnostic concentration of Cry1Ac increased from 0% in 2005-2007 to 56% in 2008-2010. However, the median survival at the diagnostic concentration was only 1.6% from 2008 to 2010 and failure of Bt cotton to control pink bollworm has not been reported in China. The early detection of resistance reported here may promote proactive countermeasures, such as a switch to transgenic cotton producing toxins distinct from Cry1A toxins, increased planting of non-Bt cotton, and integration of other management tactics together with Bt cotton.     

Early warning of cotton bollworm resistance associated with intensive planting of Bt cotton in China

Transgenic crops producing Bacillus thuringiensis (Bt) toxins kill some key insect pests, but evolution of resistance by pests can reduce their efficacy. The predominant strategy for delaying pest resistance to Bt crops requires refuges of non-Bt host plants to promote survival of susceptible pests. To delay pest resistance to transgenic cotton producing Bt toxin Cry1Ac, farmers in the United States and Australia planted refuges of non-Bt cotton, while farmers in China have relied on "natural" refuges of non-Bt host plants other than cotton. Here we report data from a 2010 survey showing field-evolved resistance to Cry1Ac of the major target pest, cotton bollworm (Helicoverpa armigera), in northern China. Laboratory bioassay results show that susceptibility to Cry1Ac was significantly lower in 13 field populations from northern China, where Bt cotton has been planted intensively, than in two populations from sites in northwestern China where exposure to Bt cotton has been limited. Susceptibility to Bt toxin Cry2Ab did not differ between northern and northwestern China, demonstrating that resistance to Cry1Ac did not cause cross-resistance to Cry2Ab, and implying that resistance to Cry1Ac in northern China is a specific adaptation caused by exposure to this toxin in Bt cotton. Despite the resistance detected in laboratory bioassays, control failures of Bt cotton have not been reported in China. This early warning may spur proactive countermeasures, including a switch to transgenic cotton producing two or more toxins distinct from Cry1A toxins.     

转Bt基因抗虫棉根际微生物区系和细菌生理群多样性的变化

在大田栽培条件下 ,以转 Bt基因抗虫棉 GK-12和常规棉花泗棉 3号作为材料 ,在棉花不同发育时期 ,于 2 0 0 1和 2 0 0 2连续两年测定棉花根际土壤细菌、放线菌和真菌数量的变化 ,并在 2 0 0 2年棉花的花铃期和吐絮期对根际细菌生理群的数量和多样性进行了分析 ,结果表明 :虽然不同年份和生育期棉花根际微生物数量存在差异 ,但是 ,年度间和相同的发育时期棉花根际微生物的数量变化趋势一致。在棉花的苗期和吐絮期 ,转 Bt基因抗虫棉根际微生物的数量与对照差异不显著 ;在棉花的花铃期 ,转 Bt基因抗虫棉根际细菌的数量比对照增加 ,放线菌的数量差异不显著 ,而真菌的数量变化没有规律。在棉花发育的花铃期和吐絮期 ,Bt棉根际细菌生理群的总数量比常规棉增加 ,但是根际细菌生理群的 Simpson指数、Shannon-Wiener指数和细菌生理群分布的均匀度下降     

Transgenic Bt cotton has no apparent effect on enzymatic activities or functional diversity of microbial communities in rhizosphere soil

A transgenic Bt cotton (Sukang-103) and its non-Bt cotton counterpart (Sumian-12) were investigated to evaluate the potential risk of transgenes on the soil ecosystem. The activities of urease, phosphatase, dehydrogenase, phenol oxidase, and protease in cotton rhizosphere were assayed during the vegetative, reproductive, and senescing stages of cotton growth and after harvest. A Biolog system was used to evaluate the functional diversity of microbial communities in soils after a complete cotton growth cycle. Enzymatic activities in soils amended with cotton biomass were also assayed. Results showed that there were few significant differences in enzyme activities between Bt and non-Bt cottons at any of the growth stages and after harvest; amendment with cotton biomass to soil enhanced soil enzyme activities, but there were no significant difference between Bt and non-Bt cotton; the richness of the microbial communities in rhizosphere soil did not differ between Bt and the non-Bt cotton, and close to that of control soil; the functional diversity of microbial communities were not different in rhizosphere soils between Bt and non-Bt cotton. All results suggested that there was no evidence to indicate any adverse effects of Bt cotton on the soil ecosystem in this study.     

种植转Bt基因抗虫棉对土壤生物学活性的影响

采用温室盆栽实验,研究了种植转Bt基因棉（苏抗103）和同源常规棉（苏棉12）对根际土壤生物学活性的影响。结果表明：与对照常规棉相比,种植转Bt基因棉对根际土壤脱氢酶、碱性磷酸酶、蔗糖酶和土壤呼吸的影响因生育期而异,土壤脲酶、蛋白酶和微生物量C在各生育期均没有显著差异;土壤蔗糖酶、土壤脱氢酶和土壤呼吸分别只在苗期（苏抗103〉苏棉12,增幅为25．5％）、花铃期（苏抗103〉苏棉12,增幅为21．6％）、花铃期（苏抗103〉苏棉12,增幅为36．1％）存在显著差异;土壤磷酸酶在花铃期和吐絮期活性显著下降（降幅分别为22．1％和32．9％）。     

Bt玉米秸秆还田对小麦幼苗生长发育的影响

以已进入中间试验阶段的Bt玉米及其亲本(非Bt玉米)秸秆为材料,与营养土及蛭石混合后培养小麦幼苗,同时以未使用秸秆的相应土为空白对照,在室内条件下研究了Bt玉米与亲本秸秆还田对后茬小麦的影响。结果表明:(1)不同秸秆还田对小麦幼苗出苗率、株高没有显著影响;(2)非转基因玉米与转Bt玉米秸秆拌土后地上部鲜重仅为对照鲜重的51%和65%,干重仅为对照的62%和72%,均达到差异显著水平;(3)Bt玉米秸秆还田降低小麦幼苗生长素(IAA)含量,郑58秸秆拌土增加了幼苗脱落酸(ABA)含量;(4)两种处理均提高了幼苗的超氧化物歧化酶(SOD)总活性。因此,秸秆拌土对小麦幼苗的处理效应一致,与秸秆类型无关,该研究可为评价转Bt玉米环境安全提供一定的理论依据。     

Helicoverpa armigera baseline susceptibility to Bacillus thuringiensis Cry toxins and resistance management for Bt cotton in India

Transgenic cotton that produces insecticidal proteins from Bacillus thuringiensis (Bt), often referred to as Bt cotton, is widely grown in many countries. Bt cotton with a single cry1A gene and stacked also with cry2A gene has provided satisfactory protection against the damage by the lepidopteran bollworms, especially the cotton bollworm, Helicoverpa armigera (Hübner) which is considered as a key pest. The baseline susceptibility of the larvae of H. armigera to Cry1Ac and other toxins carried out in many countries has provided a basis for monitoring resistance. There is no evidence of development of field-level resistance in H. armigera leading to the failure of Bt cotton crop anywhere in the world, despite the fact that Bt cotton was grown on the largest ever area of 12.1 million hectares in 2006 and its cumulative cultivation over the last 11 years has surpassed the annual cotton area in the world. Nevertheless, the Bt resistance management has become a necessity to sustain Bt cotton and other transgenic crops in view of potential of the target insects to evolve Cry toxin resistance.     

转Cry1Ac+Cry2Ab棉花生长势及其对棉田节肢动物物种丰富度的影响

【背景】转基因棉花在商业化种植之前,必须评价其环境安全性。其中新型棉花材料的生存竞争能力和对物种丰富度的影响是评价的重要内容。【方法】以转Cry1Ac＋Cry2Ab基因棉为试验材料,转Cry1Ac棉花中棉所41和非转基因棉花中棉所49为对照品种,分别于2014年5~9月对棉花株高、主茎叶片数、叶绿素含量、比叶面积、果枝数、蕾铃数等生长参数进行比较,同时对二代、三代和四代棉铃虫发生期棉田物种丰富度进行系统调查。【结果】转Cry1Ac＋Cry2Ab棉花的生长势与转Cry1Ac棉花和非转基因棉花基本相当,没有表现出明显的竞争优势;产量构成参数在成铃和脱落等方面比非转基因棉表现出良好的优势。对棉田节肢动物物种丰富度的影响表明,转Cry1Ac＋Cry2Ab棉花对靶标害虫棉铃虫具有良好的控制效果,对主要刺吸性害虫棉蚜、棉蓟马、烟粉虱、绿盲蝽与天敌龟纹瓢虫、草间小黑蛛、草蛉和小花蝽等的种群丰富度在个别时期有所影响,但总体上与转Cry1Ac棉田和非转基因棉田没有显著性差异。【结论与意义】转Cry1Ac＋Cry2Ab棉花无竞争优势,但目标性状优势较好;对棉田节肢动物物种丰富度无明显影响。研究结果为新型转Cry1Ac＋Cry2Ab棉花对棉田环境安全方面的研究进一步补充了内容,为转基因棉花的环境安全评价提供科学数据。