草地贪夜蛾在小麦和不同玉米品种上的种群适合度比较

草地贪夜蛾Spodoptera frugiperda(J.E.Smith)是新入侵我国的重大迁飞性害虫,2019年在我国黄淮海冬小麦-夏玉米轮作主产区河南省呈点片发生,主要为害玉米,特别偏好取食晚播的甜糯玉米。为明确草地贪夜蛾在小麦和不同玉米品种上的种群适合度是否存在差异,本研究在室内(26±1)℃,RH(65±5)%和L//D=16 h//8 h光周期条件下比较了草地贪夜蛾在普通玉米‘郑单958’‘郑单1002’‘豫研1501’和糯玉米‘郑黄糯2号’以及小麦‘郑麦366’上生长发育指标。结果表明:取食‘郑麦366’的草地贪夜蛾的化蛹率(44.00±3.40)%、蛹重(138.62±6.76)mg、羽化率(35.00±3.07)%和单雌产卵量(971.70±125.63)粒均低于取食4个玉米品种的化蛹率(73.33%～80.00%)、蛹重(154.94～176.40)mg、羽化率(73.33%～79.33%)和单雌产卵量(1 052.00～1 322.60)粒(P0.05);草地贪夜蛾取食不同寄主植物的种群趋势指数由大到小顺序为:‘郑黄糯2号’(578.38)‘豫研1501’(493.40)和‘郑单958’(437.06)‘郑单1002’(321.47)‘郑麦366’(133.56)。综上表明,草地贪夜蛾在小麦上的适合度低于在玉米上的适合度,但其能够在小麦上完成生长发育并实现种群扩繁;其在糯玉米上的种群适合度大于普通玉米。因此应密切监测草地贪夜蛾在小麦上的发生和为害,并提出适时种植糯玉米作为诱集带并集中喷施杀虫剂来压低草地贪夜蛾种群数量的防控措施。     

Impacts of Cucurbit Chlorotic Yellows Virus (CCYV) on Biological Characteristics of Its Vector Bemisia tabaci (Hemiptera: Aleyrodidae) MED Species

Plant viruses can change the phenotypes and defense pathways of the host plants and the performance of their vectors to facilitate their transmission. Cucurbit chlorotic yellows virus (CCYV) (Crinivirus), a newly reported virus occurring on cucurbit plants and many other plant species, is transmitted specifically by Bemisia tabaci MEAM1 (B biotype) and MED (Q biotype) cryptic species in a semipersistent manner. This study evaluated the impacts of CCYV on B. tabaci to better understand the plant-virus-vector interactions. By using CCYV-B. tabaci MED-cucumber as the model, we investigated whether or how a semipersistent plant virus impacts the biology of its whitefly vector. CCYV mRNAs were detectable in nymphs from first to fourth instars and adults of B. tabaci with different titers. Nymph instar durations and adult longevity of female whiteflies greatly extended on CCYV-infected plants, but nymph instar durations and adult longevity of male whiteflies were not significantly influenced. In addition, the body length and oviposition increased in adults feeding on CCYV-infected plants, but the hatching rates of eggs and survival rates of different stages were not affected. Most interestingly, the sex ratio (male:female) significantly reduced to 0.5:1 in whitefly populations on CCYV-infected plants, while the ratio remained about 1:1 on healthy plants. These results indicated that CCYV can significantly impact the biological characteristics of its vector B. tabaci. It is speculated that CCYV and B. tabaci have established a typical mutualist relationship mediated by host plants.     

遗传算法及其在渔饲料配方中的应用

首先阐述了参数编码、初始群体、适应度函数、遗传操作以及算法控制参数等遗传算法基本原理,然后着重介绍其在渔饲料配方中的应用,在该应用中采用了实数编码、基于线性排名的选择、算术杂交和非一致变异等遗传算法方法。结果表明,在渔饲料配方优化中应用遗传算法要优于目前饲料配方软件中大多采用的常规应用数学的优化方法。主要体现在单位产量饲料配方中的成本价格前者要低于后者。由于遗传算法能够解决因子较多,非线性程度高的问题,从而得出的饲料配方能更好的符合相关鱼种的营养含量标准。     

Comparative performance of hatchery-reared and wild Scylla paramamosain (Estampador, 1949) in pond culture

The performance of hatchery‐reared juveniles either in aquaculture grow‐out systems or stock enhancement is likely to be dependent on a range of factors during the hatchery phase of production. With recent progress in the development of hatchery systems for the mud crabs Scylla spp., there is growing interest in evaluation of the quality of hatchery‐reared juveniles relative to wild seed crabs as currently used in aquaculture. Hatchery‐reared and wild‐collected Scylla paramamosain juveniles were stocked either together in ponds or separately. All crabs were tagged with microwire‐coded tags, so that origin could be determined in the mixed groups. Preliminary validation demonstrated that tagging did not affect survival or growth, with a tag retention of 94%. After 106 days of culture, there was no significant difference in survival at harvest between the two sources of crabs. The wild juvenile crabs had a significantly higher initial weight:carapace width (CW) ratio compared with those from the hatchery, indicating a difference in condition. However, where crabs were stocked separately, the hatchery‐reared animals exhibited significantly faster growth than those collected from the wild, both in terms of specific growth rate and CW increase per month. However, in the mixed ponds, where there was competition with wild crabs, there was no significant difference in growth rate between crabs from the two sources. Overall, the results demonstrate that the growth performance of hatchery‐reared S. paramamosain can at least equal that of wild‐collected seed crabs in ponds culture.     

棉蚜种群密度对其转主取食适合度的影响

为了明确种群密度对棉蚜(Aphis gossypiiGlover)转主取食适合度的影响,通过室内转接试验,研究了采自棉花和黄瓜的棉蚜品系分别以不同种群密度转接到棉花和黄瓜上的成虫留居率和种群增长率。结果表明:种群密度对于两品系棉蚜的成虫留居率均没有显著影响;在不转换寄主的情况下(棉花品系/棉花、黄瓜品系/黄瓜),种群密度对于两品系的种群繁殖率均没有显著影响;寄主转换后(棉花品系/黄瓜、黄瓜品系/棉花),种群密度对两品系的种群繁殖率有显著影响,均表现为以30头/株转接,种群繁殖率显著高于以10、50、70头/株转接,而后三者之间没有显著差异(P>0.05);棉花品系/棉花的种群适合度显著高于棉花品系/黄瓜种群,黄瓜品系/黄瓜的种群适合度显著高于黄瓜品系/棉花种群。     

多次交配对昆虫适应性的影响

多次交配行为广泛存在于各种昆虫种类中.然而,目前对于昆虫多次交配行为的维持与进化的理解仍然存在疑惑.从物质利益和基因利益两方面综述昆虫多次交配发生的机制,并从亲代的产卵量、寿命、生殖力、子代的存活力与基因多样性等方面论述多次交配对昆虫适应性的影响.     

2株不同地区辣椒疫霉菌株生物学性状初步研究

对来自于南京和广州地区的2株辣椒疫霉菌株NN和HN进行生长速率、孢子囊形态、药剂敏感性和菌体蛋白质分析,研究其生物学性状的差异。结果表明,NN菌株和HN菌株在PDA、胡萝卜、玉米粉、番茄汁、大豆、10%V8等6种培养基上均能生长,但生长速率不同,NN菌株在各种培养基上的生长速率均显著高于HN菌株;2个菌株在PDA上形成的菌落存在显著性差异,NN菌株菌落气生菌丝多,而HN菌株菌落表面光滑;2菌株在10%V8培养液中培养后经无菌水诱发产生孢子囊,它们的孢子囊形态存在一定差异,NN菌株孢子囊形态多样,多达6种,以梨形和椭圆形为主,HN菌株多以椭圆形为主;供试的甲霜灵、霜脲锰锌、甲霜灵锰锌、代森锰锌、甲霜灵.霜霉威、百菌清等6种药剂对2菌株都有不同程度的抑制作用,其中甲霜灵对2个菌株的抑制作用最大,2个菌株对各种药剂的适应性在低浓度差异大多表现为不显著,但在高浓度差异显著;对这2株菌株的菌体蛋白进行聚丙烯酰胺凝胶电泳法分析,结果显示,2个菌株菌体蛋白的相似率达85%,存在3个菌体蛋白的差异。     

基于生态位适宜度的农村居民点布局研究——以武汉市新洲区为例

农村居民点是农村人口生产、生活等综合功能的承载体,研究其内部结构、空间布局对改善农村生产生活水平、保护耕地、缓解建设用地压力,推进社会主义新农村建设进程具有重要作用.首先,在MapGIS的支持下,利用数理统计法探究了新洲区农村居民点布局结构、特征规律以及存在的问题;其次,依据生态位理论,构建了新洲区农村居民点生态位适宜度模型,将新洲区划分为高度适宜区、中度适宜区、低度适宜区和不适宜区4个等级.最后,在分区布局的基础上,采用以点带面,整体推进的方式,形成了“一轴、两核、三级、四带、中心村”的居民点布局格局,对新洲区农村居民点布局进行了优化.结果表明:农村居民点优化布局可采取先分区后布局的规划思路;生态位适宜度模型能很好地实现农村居民点的分区,结合规划思想和工具,可以作为农村居民点规划布局的有效手段.     

棉铃虫寄主潜在适合度表达的影响因素研究

通过大面积分类系统调查、田间自然为害试验与罩笼接蛾试验 ,对棉铃虫主要寄主潜在适合度表达的影响因素进行了研究。结果表明 :主要寄主作物对棉铃虫的潜在适合度的表达程度都以生殖生长阶段优于营养生长阶段 ,不同生育期之间都以开花期适合度最高。影响同一寄主作物适合度的主要因素除生育期以外 ,还有品种抗性、寄主生长势、棉铃虫发生代次与种群数量、环境气候因素与作物布局等。感虫品种、寄主生长势强、棉铃虫主害代与发生基数大、环境气候适宜等 ,棉铃虫寄主适合度表达程度就高。据此 ,可进一步优化棉铃虫种群调查测报与防治决策