基于城市化进程下的失地农民问题研究          下载免费PDF全文

杨俊霞 《现代农业研究》2020,(4):137-138

由于我国城市化的进程飞速发展,使得许多的农村土地被国家大量的征收,这使一个特殊群 体快速地在社会中占据了一定的比例,就是失地农民。他们既不是农民却又与城市中的居民不同。 这种群体的产生是每一个国家在发展中都会遇到的问题,而对于该群体在社会中的生存也成为一项 重要的问题。因此,文章以城市化进程中失地农民的问题以及原因入手,提出了解决城市化进程下失 地农民问题的策略,以供参考。  相似文献   

Artificial Feeding and Laboratory Rearing of Endangered Saproxylic Beetles as a Tool for Insect Conservation     

Teresa Bonacci  Mattia Rovito  Jakub Hork  Pietro Brandmayr 《Journal of insect science (Online)》2020,20(5)

Conservation of threatened animals is frequently limited by lack of knowledge about their ecological preferences, and often artificial feeding is one of the few chances to save endangered species. We investigated the possibility to artificially feed two endangered flat bark beetles dependent on dead wood for their diet—namely, Cucujus cinnaberinus (Scopoli, 1763) and Cucujus haematodes Erichson, 1845—by examining their dietary preferences, life cycle duration, and survival in laboratory conditions. Individuals of the two species were caught in the wild and larvae and adults were fed in laboratory conditions by live or dead prey. Three species of saproxylic beetles: two cerambycids (Acanthocinus griseus Fabricius, 1793 and Rhagium inquisitor Linnaeus, 1758), one scolytid (Ips sexdentatus Börner, 1776) one tenebrionid (Tenebrio molitor (Linnaeus, 1758)) one dipteran (Lucilia sericata (Meigen, 1826)) and one ant (Lasius sp. Fabricius, 1804) were used as prey, with minced meat as a control. Our results indicated high survival and no difference in prey choice between the two flat beetle species. Larvae and adults preferred dead prey, but no significant preference was detected among dead prey taxa, supporting the hypothesis that the two species are opportunistic scavengers. Comparing data with previous results, both species and their developmental stages should be classified as obligate saproxylic organisms with preference to the dead and decaying organic material. Successful artificial feeding and rearing of these endangered species, followed by the release in the wild through rescue or reintroduction programs, therefore appear relevant for their protection and future conservation.  相似文献   

Artificial Diet Influences Population Growth of the Root Maggot Bradysia impatiens (Diptera: Sciaridae)     

Yuping Gou  Peter Quandahor  Kexin Zhang  Sufan Guo  Qiangyan Zhang  Changzhong Liu  Jeffrey A Coulter 《Journal of insect science (Online)》2020,20(5)

In order to investigate the effects of artificial diets on the population growth of root maggot Bradysia impatiens, its population growth parameters were assayed on eight artificial diets (Diet 1, D2, D3, D4, D5, D6, D7, and D8). Results showed that developmental duration from egg to pupa was successfully completed on all eight artificial diets. However, the egg to pupal duration was shortest, while the survival rate of four insect stages was lowest when B. impatiens was reared on D1. When B. impatiens was reared on D7 and D8, the survival rate, female longevity, and female oviposition were higher than those reared on other diets. When B. impatiens was reared on D7, the intrinsic rate of increase (r_m = 0.19/d), net reproductive rate (R₀ = 39.88 offspring per individual), and finite rate of increase (λ = 1.21/d) were higher for its population growth with shorter generation time (T = 19.49 d) and doubling time (Dt = 3.67 d). The findings indicate that the D7 artificial diet is more appropriate for the biological parameters of B. impatiens and can be used an indoor breeding food for population expansion as well as further research. We propose that vitamin C supplement added to the D7 is critical for the improvement of the B. impatiens growth.  相似文献   

Evaluation on the fitness and population projection of Nilaparvata lugens in response to elevated CO2 using two-sex life table     

Dong Wen  Jinping Liu  Shuai Fan  Gang Wu 《国际虫害防治杂志》2020,66(4):368-377

Abstract

The life history and fitness of Nilaparvata lugens being reared under ambient level (current CO₂ concentration), medially elevated (550?µL/L) and highly elevated (750?µL/L) CO₂ concentration for long-term generation were compared using two-sex life table instead of traditional age-specific life table. The results showed that significantly longer larval duration and lower fecundity of N. lugens were observed in 750?µL/L relative to 550?µL/L treatment (P?<?0.05). Accordingly, 550?µL/L CO₂ significantly enhanced population parameters of N. lugens, including significantly higher intrinsic rate of increase (r), finite rate (λ) and net reproductive rate (R_O), but not for 750?µL/L CO₂. Taken together, N. lugens performs enhanced development rate, fecundity and survival in individual life history and higher potential in population multiplication under 550?µL/L CO₂ level, while only indicates the less enhanced development rate and survival without significant increased capacity of population expansion under 750?µL/L CO₂ level. These results should facilitate predicting the fitness and potential population damage of N. lugens, which is valuable for the integrated control of N. lugens in the future increasing CO₂ concentration.  相似文献   

Lethal and sublethal effects of fluralaner on the two‐spotted spider mites,Tetranychus urticae Koch (Acari: Tetranychidae)     

Kipchoge Leviticus  Li Cui  Han Ling  Zhong‐Qiang Jia  Qiu‐Tang Huang  Zhao‐Jun Han  Chun‐Qing Zhao  Lu Xu 《Pest management science》2020,76(3):888-893

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草地贪夜蛾对小麦和玉米的产卵选择性及其种群生命表     

巴吐西  张云慧  张智  关豆豆  李翠翠  季昭云  殷新田  张爱环  汤清波  刘延辉  李祥瑞  朱勋 《植物保护》2020,46(1):17-23

为明确草地贪夜蛾对小麦的产卵选择性及其是否对小麦安全生产构成威胁,本研究以玉米和小麦作为测试寄主,比较分析了草地贪夜蛾对两种作物不同部位的产卵选择性,并利用两性生命表方法研究了取食小麦、玉米对其生命参数的影响。结果表明:草地贪夜蛾更喜欢在玉米上产卵,其在玉米、小麦叶片、玉米和小麦茎秆上的产卵量存在显著差异(df=102,F=15.593,P<0.05),以玉米叶片背面卵块数量(7.11±1.55)块/笼最高;草地贪夜蛾取食小麦可以完成生活史,但幼虫存活率、化蛹率、羽化率和世代存活率低于取食玉米。取食玉米的幼虫发育历期为(16.31±0.15)d,显著高于取食小麦的(14.66±0.12)d,蛹期、蛹重、产卵前期、成虫寿命和世代周期无显著差异。取食小麦羽化出的雌虫寿命、平均单雌产卵量显著高于取食玉米,分别为(16.39±0.40)d、(976.31±57.21)粒和(14.64±0.32)d、(831.57±30.55)粒。生命表参数显示取食玉米的净增殖率为363.14,显著高于小麦的258.63,但内禀增长率、周限增长率和平均世代周期无显著差异。研究结果为草地贪夜蛾在小麦上的预测预报和有效防控提供了基础数据。  相似文献   

鄱阳湖区反嘴鹬种群数量动态与空间分布格局     

涂翔宇  牟庆茹  李言阔  涂晓斌 《东北林业大学学报》2020,(3):89-94

2002—2015年,采用同步调查法对鄱阳湖区反嘴鹬(Recurvirostra avosetta)越冬种群数量动态与空间分布格局进行了监测。结果表明:鄱阳湖区分布有稳定的反嘴鹬越冬种群,年平均数量为(16684±14653)只,2004年、2005年、2013年种群数量均超过目前其全球数量的10%,2004年冬季鄱阳湖区越冬反嘴鹬数量达到最大值,为47520只。鄱阳湖区共有70个湖泊记录到反嘴鹬,其中反嘴鹬种群数量达到全球1%以上的湖泊有20个。每年冬季鄱阳湖区反嘴鹬集中分布在常湖、蚌湖、花庙湖和下坝湖,而反嘴鹬利用频次最高的是大湖池,每年反嘴鹬的越冬数量为(1819±1593)只。各湖泊中反嘴鹬的年平均数量与利用频次之间不存在显著相关性。自然保护区涵盖了反嘴鹬在鄱阳湖越冬的主要湖泊,分布在保护区内的反嘴鹬种群占鄱阳湖区越冬总数量的(75.3±26.0)%,但仍有很多重要的湖泊没有被纳入到保护区范围。反嘴鹬对保护区内湖泊的利用频次与保护区外湖泊的利用频次不存在显著性差异,保护区内反嘴鹬的种群数量显著大于保护区外。  相似文献   

不同浓度明矾对康乃馨切花的保鲜效应     

杨运英  杨晓春  王廷芹 《广东农业科学》2020,47(4):47-53

【目的】探究不同浓度明矾对康乃馨切花的保鲜效果,为康乃馨开发保鲜剂提供借鉴。【方法】以小桃红康乃馨为材料,3%蔗糖+200 mg/L柠檬酸+200 mg/L 8-HQS为基础液,在基础液中分别加入不同浓度明矾进行瓶插试验,研究康乃馨切花的瓶插寿命、鲜重变化率及其他生理生化变化情况。【结果】不同浓度明矾处理延长了康乃馨瓶插寿命,其中基础液添加180 mg/L明矾处理效果最佳,比空白对照延长切花瓶插寿命3.5 d。瓶插过程中,该处理切花鲜重变化率瓶插6 d后保持较高水平;瓶插4 d后,水分平衡值小于0,比对照延迟了出现水分平衡值为负的时间,保持较好的吸水保水能力。可溶性糖含量比对照高,增加细胞液浓度,瓶插3 d后POD和CAT活性比对照高,有效清除活性氧自由基,瓶插6 d后康乃馨切花花瓣相对电导率和MDA含量低于对照,有利于康乃馨花瓣细胞膜完整性,增强抗逆性,延缓衰老。【结论】基础液添加180 mg/L明矾处理有效延长了康乃馨的瓶插寿命,改善康乃馨切花体内的水分状况,提高酶活性清除更多的自由基,降低相对电导率和MDA含量,保持细胞膜的完整性;提高可溶性糖含量,调节细胞渗透压,延缓衰老,延长康乃馨切花的保鲜期。  相似文献   

茶让生活更美好     

王岳飞 《农业考古》2020,(2):39-44

茶作为中华民族的举国之饮,是中华传统文化的集中体现,也是彰显健康生活的民生产业。如今,中国茶在新时代的脉络中展现了蓬勃的生机与活力,迎来了发展的黄金时代。本文从茶产业、茶文化、茶科技和茶健康等角度全方位论述了中国茶的影响、地位、贡献和前景,解读茶让人民生活更美好的时代愿景。  相似文献   

现代生活中的楚雄彝族烤罐茶习俗     

王倩倩 《农业考古》2020,(2):84-88

彝族的茶文化有着悠久的历史,“烤罐茶”习俗是彝族人在漫长的历史进程中创造出来的文化传统,是彝族火塘茶艺与地域特色文化的有机结合。在彝族人的观念中,“茶”作为生活中的必需品也蕴含着他们图腾崇拜意识、待人接物的礼仪文化和民族之间凝聚力的表达等多种文化因素。新时代背景下,彝族的烤罐茶在历史的发展过程中得到传承,也蕴含着现代人的养生观念。本文以楚雄彝族烤罐茶习俗为研究对象,探索现代生活中的彝族烤罐茶习俗的传承发展及其丰富的文化内涵。  相似文献