稻田蜘蛛对弹尾虫的功能反应及选择作用

作者在室内研究了拟环纹豹蛛和草间小黑蛛对弹尾虫的功能反应和选择作用。结果表明,两种蜘蛛对弹尾虫的功能反应均为Ⅱ型反应,并存在极显著的差异,拟环纹豹蛛对弹尾虫的功能反应明显强于草间小黑蛛,其对弹尾虫的控制作用（ａ／Ｔｈ＝３９．７５８）是草间不黑蛛（１３．０３１）的３倍左右。弹尾虫和白背飞虱共存时,两种蜘蛛的功能反应变为Ⅲ型反应,并对弹尾虫都具有明显的偏好性,弹尾虫的存在降低了两种蜘蛛对白背飞虱的捕食     

不同种类柑橘的密码子用法分析

采用高频密码子分析法,对甜橙Citrus sinensis、温州蜜柑C．unshiu、葡萄柚C．paradisi和柠檬C.limon等4种柑橘的蛋白质编码基因序列（eodon DNA sequence,CDS）进行了分析,计算出了柑橘同义密码子相对使用频率（relative frequency of synonymous codon,RFSC）,确定出了4种柑橘的高频率密码子,发现不同种类柑橘偏爱密码子稍有差别．     

政府补助对于我国农业上市公司财务绩效的影响

伴随着近年来我国经济的快速发展,以及城镇化建设的不断推进,城乡协同发展成为了当前 建设的一个重中之重。但就实际情况来看,我国农村地区始终都存在着产业类型较为单一、生产力低 下的情况,而这也导致农村地区的贫困人口较多。正是在这样的背景下,精准扶贫政策开始走进社会 公众的视野。而精准扶贫政策的出台,对于改善农村经济整体落后的情况来讲,有着重大的意义。基 于此,本文将以农村经济如今发展状况为切入点,继而围绕着其展开论述。     

Differential host residence of adult cryptomeria bark borer,Semanotus japonicus Lacordaire (Coleoptera: Cerambycidae), in relation to tree size of Japanese cedar,Cryptomeria japonica D. Don

To understand factors involved in tree-size dependent vulnerability ofCryptomeria japonica to damage bySemanotus japonicus, residence of adultSemanotus japonicus on host trees was assessed in twoCryptomeria japonica stands, using band trap method and mark-recapture techniques. Adult capture distributions among trees were analyzed in relation to diameter size of each tree. Female adults consistently exhibited more frequent residence on larger trees, under different field conditions. Females that made inter-tree movements preferentially chose larger trees as their destinations. Frequent residence by females on large trees was associated with high productivity of progeny adults. Male adults were also more frequently resident on larger trees. These results suggest that tree-size dependent oviposition accounts for the tree-size dependent vulnerability ofCryptomeria japonica to damage bySemanotus japonicus. Possible causes underlying the differential host residence of adultSemanotus japonicus are discussed.     

组合蛋白酶对肉仔鸡采食偏好性、血清生化指标和肠道组织形态的影响

本试验旨在探讨组合蛋白酶对肉仔鸡采食偏好性、血清生化指标和肠道组织形态的影响.试验1采用自由选择试验法,选择1日龄体况相近、健康的爱拔益加(AA)肉仔鸡40只,随机分为4个处理,每个处理10只鸡.4个处理的肉鸡同时饲喂基础饲粮(饲粮Ⅰ)以及在基础饲粮中分别添加4(饲粮Ⅱ)、8(饲粮Ⅲ)和12 U/g(饲粮Ⅳ)组合蛋白酶...     

Substrate type and brightness preference of Schizothorax wangchiachii and Percocypris pingi juveniles

It is advantageous for fish to choose different substrate types and brightness based on their current life cycle stage, foraging requirements, predator avoidance and water conditions. We determined the substrate type and brightness preference of hatchery‐reared and wild juvenile Schizothorax wangchiachii and Percocypris pingi under laboratory conditions. Individuals and groups were exposed to four kinds of substrate types (sand: diameter < 1 mm, small gravel: diameter approximately 2–3 cm, large gravel: diameter approximately 10–15 cm, sand and medium gravel mix: diameter approximately 4–7 cm) and two kinds of substrate brightness (black and white). The results showed that hatchery‐reared and wild S. wangchiachii and P. pingi significantly preferred large gravel and black substrates regardless of the number of fish (p < .05). P. pingi had a significantly higher preference for black substrate than S. wangchiachii both in hatchery‐reared and wild individuals (p < .05). Hatchery‐reared and wild individuals of the two species shared a preference for large gravel and black substrates suggesting that substrate preferences might be genetically based. The findings in the present study could be used to improve the rearing conditions for the two species in hatchery and thereafter to enhance its adaptability after releasing to the wild.     

红白鲫对不同背景颜色的选择偏好

为探究鱼类对背景颜色的选择偏好,以红白鲫(Carassius auratus)为研究对象,分别记录个体和群体条件下红白鲫在不同彩色(红、橙、黄、绿、青、蓝、紫)背景和白色背景中的停留时间以及往返次数。结果显示,实验连续观测20 min,在个体条件下,红白鲫在白色和彩色背景中的停留时间没有显著差异(P0.05),在各单色背景中的停留时间也没有显著差异(P0.05);且其在白色与不同彩色背景间的往返次数从大到小依次为:绿色(17.5次)蓝色(15.7次)青色(15.3次)紫色(13.4次)橙色(12.0次)红色(10.0次)黄色(9.0次)。在群体条件下,与白色背景相比,红白鲫在橙色、黄色背景中停留时间显著更长(P0.05),在红色背景中停留时间显著更短(P0.05),而在其他彩色背景中停留时间没有显著差异(P0.05);不同单色背景对红白鲫的停留时间有显著影响(P0.05),其中在橙色、黄色背景中停留时间显著长于红色背景(P0.05),而其他单色两两之间停留时间无显著差异(P0.05);且其在白色与不同彩色背景间的往返次数从大到小依次为:红色(15.1次)橙色(14.0次)黄色(13.6次)蓝色(12.2次)绿色(11.8次)青色(10.2次)紫色(9.1次)。研究表明,红白鲫对背景颜色具有一定的选择偏好,特别是在群体条件下偏好于橙色和黄色,不喜欢红色。     

Aspects of the feeding biology of the copepod Pseudodiaptomus hessei (Copepoda: Calanoida) under culture conditions

This study aimed to investigate the feeding behaviour (particularly gut fullness and evacuation, preying on rotifers and feeding preference in the water column) of the calanoid copepod, Pseudodiaptomus hessei, as a potential live feed species for aquaculture. Fed and starved, male and female P. hessei were fed rotifers (Brachionus plicatilis) in the presence and absence of microalgae for 24 hr. Starved copepods consumed more rotifers (11.31 ± 1.01, individual rotifers) than fed (8.06 ± 1.01, individual rotifers) while the number of rotifers consumed in the presence of microalgae was similar when fed or starved. Gut fullness and evacuation was determined by feeding copepods two different cell size microalgae species (Tetraselmis suecica and Isochrysis galbana). Gut fullness and evacuation percentage were observed under the dissecting microscope (as 0, 25, 50, 75 and 100%). Copepods fed on T. suecica (large cell) filled their guts more rapidly, while those fed on I. galbana (small cell) evacuated their guts faster. Feeding preference was determined using a multifactorial experiment where copepods were fed two microalgae species, T. suecica and I. galbana, each presented as benthic and planktonic food sources. P. hessei preferred to feed on planktonic microalgae first regardless of microalgae choice species for ±80 min, before shifting to benthic food source. This information can be used as baseline information for aquaculturists to rear the species as live feed for marine fish larvae.     

北京城镇居民鲜食玉米市场细分研究

本研究通过查阅相关文献,在掌握一定的研究方法和理论基础的前提下,通过设计调查问卷,就“北京市城镇居民鲜食玉米消费特征”,对消费者进行一对一的面对面访谈,获得了有关北京市城镇居民鲜食玉米购买和消费的相关调研数据,通过描述统计、交叉分析等方法分析调研数据,并根据消费者对鲜食玉米不同的购买和消费特征,进行了市场细分。研究表明：随着学历和收入的提高,消费者选择在高档餐馆和单位食堂食用鲜食玉米的比例逐渐增加,且对鲜食玉米价格的敏感程度随之降低;户外消费鲜食玉米的场所,企事业单位人员主要是在单位食堂,城市自由职业者主要是在一般餐馆,个体经商者主要是在路边临时餐饮场所,离退休人员和待业人员主要是在一般餐馆和路边场所;随着年龄的增加,鲜食玉米的消费受季节的影响就越明显,对价格的重视程度也逐渐增加;男性更偏好在高档场所就餐时消费鲜食玉米,女性则偏好在路边的便捷场所消费。购买鲜食玉米时,女性较男性更容易受到季节的影响。根据消费者购买和消费鲜食玉米的特征,将鲜食玉米细分为两个子市场：情感动机型子市场和理智动机型子市场。情感动机型子市场的消费者,具有需求购买和情绪体验购买占主导的特征,在购买和消费鲜食玉米时,更关注心理和物质的需求等因素;理智动机型子市场的消费者,具有客观性、周密性、控制性特征,在购买和消费鲜食玉米时,更关注产品的属性、购买环境、消费成本等因素。     

棉铃虫雌成虫对16种植物的产卵偏好性及幼虫取食后的生存表现

为研究棉铃虫成虫寄主偏好性和幼虫取食后生存表现之间的关系,明确两者在决定寄主过程中的作用,我们测定了交配后的棉铃虫雌成虫对16种植物(棉花、玉米、大豆、花生、番茄、辣椒、茄子、烟草、黄瓜、胡萝卜、西芹、杨树、月季、菠菜、包菜、大葱)的产卵偏好性和幼虫取食这些植物嫩叶后的存活和发育情况。棉铃虫雌成虫选择在烟草、茄子、棉花、胡萝卜、番茄、辣椒、玉米、西芹、大豆和花生等10种植物上产卵,但只有取食西芹、烟草、番茄、大豆、棉花和胡萝卜等6种植物叶片的初孵幼虫能够完成幼虫阶段的生长发育、化蛹并羽化,且取食植物嫩叶的幼虫的存活率、发育历期、蛹期和蛹重均差于取食人工饲料的幼虫。以上结果表明,棉铃虫雌成虫产卵寄主与其幼虫取食寄主之间存在并非一一对应的关系,幼虫的生存表现限定了棉铃虫的寄主范围。