A releaser pheromone that attracts methyltestosterone- treated immature fish in the urine of ovulated female rainbow trout

SUMMARY: Behavioral experiments concerning a releaser pheromone in the urine of female rainbow trout were performed using immature fish administered orally with 17α-methyltestosterone (MT) during the non-spawning season. The urine was collected by catheter. The frequency of entries of test fish was recorded in each channel scented by test and control solutions in a Y-maze trough. The behavior of both MT-treated and control fish demonstrated that they could not discriminate the differences between distilled and environmental water as control solutions. There was also no difference between MT-treated and control fish when distilled and environmental water were introduced. The MT-treated immature fish were attracted to the channel scented by ovulated female urine. Neither coelomic fluid nor the immature female urine had any effect on the behavioral responses of MT-treated fish, while immature control fish had no preference for the urine of ovulated females. These results suggest in rainbow trout that ovulated female urine contains a releaser pheromone to attract mature males, and that androgens are involved in the sensory mechanisms detecting the releaser pheromone in fish.     

Scale of heterogeneity of forage production and winter foraging by elk and bison

The relationship between fine-scale spatial patterns of forage abundance and the feeding patterns of large ungulates is not well known. We compared these patterns for areas grazed in winter by elk and bison in a sagebrush-grassland landscape in northern Yellowstone National Park. At a fine scale, the spatial distribution of mapped feeding stations in 30 m × 30 m sites was found to be random where there were no large patches devoid of vegetation. In areas similar to the mapped sites, the underlying spatial distribution pattern of biomass was also determined to be random. At a broad scale, forage biomass differed among communities across the northern range but forage quality did not. These results suggest that ungulates are feeding randomly within forage patches (fine scale) but may select feeding sites based upon forage abundance at broader, landscape scales. Contrary to what has been suggested in other systems, ungulates were not overmatching at finer scales.     

肉仔鸡生长过程中行为与产热的变化

研究肉仔鸡成长过程中行为变化对产热量的影响 ,将 2日龄肉仔鸡 36只分为自由摄食、 50 %摄食和绝食 3组进行观测。立位行为集中在明期 ,特别是摄食 30min前后 ,暗期几乎没有出现立体行为。 2日龄时 ,每天约有 70 0min是立位的 ,其后 ,随着日龄的增加而减少。在自由采食区 ,公雏比母雏摄食时间长。 50 %摄食区较自由采食区的摄食时间少。在绝食区 ,随着日龄的增加 ,公母的立位时间呈现减少倾向。 2 1日龄之前随着日龄的增加其摄食时间也增加 ,其后呈现相反倾向。产热 (HP ,kJ/kg0 75)与摄食时间有相同倾向。在 2 1日龄前公雏的HP比母雏低 ,2 1日龄后母雏比公雏低。 1天中各个区的HP活动规律是摄食后 1h内最高 ,暗期降低 ;限制摄食量后 ,HP降低 ,明期和暗期的HP差也随之减小     

土壤熏蒸剂研究进展

土壤熏蒸剂可有效防治土传病虫害,但效果最好的熏蒸剂溴甲烷由于破坏臭氧层,已被禁止用在农业上(必要用途豁免除外)。碘甲烷、氯化苦、异硫氰酸甲酯、1,3-二氯丙烯、二甲基二硫、硫酰氟、棉隆及威百亩是国际上已经登记使用的土壤熏蒸剂;甲酸乙酯、乙二腈、糠醛、丙烯醛是有希望开发为新的土壤熏蒸剂品种。国内已经商品化的土壤熏蒸剂品种有4种,分别为氯化苦、威百亩、棉隆和硫酰氟,二甲基二硫正在登记当中。本文系统综述了上述熏蒸剂在应用、环境行为等方面的研究进展,在未来一段时间内,氯化苦、棉隆及威百亩将会占据着国内土壤熏蒸剂的主要市场。二甲基二硫的登记也将会改善国内熏蒸剂品种匮乏的局面。     

Harmonic radar: efficacy at detecting and recovering insects on agricultural host plants

BACKGROUND: In pest management research, harmonic radar systems have been largely used to study insect movement across open or vegetation‐poor areas because the microwave signal is attenuated by the high water content of vegetation. This study evaluated whether the efficacy of this technology is sufficient to track insects in vegetative landscapes. RESULTS: Field efficacy data were collected using portable harmonic microwave radar and electronic dipole tags mounted on adults of three economically important pests: Leptinotarsa decemlineata (Say), Diabrotica virginifera virginifera (LeComte) and Conotrachelus nenuphar Herbst. Detection and recovery of tagged Colorado potato beetles, plum curculios and western corn rootworms was high within and among potato plants, moderate within apple trees and high within, but not between, corn plants respectively. The efficacy of the radar depends on the ability of the operator to move around the host, scanning for a signal ‘sightline’ with the tagged insect among plant structures. CONCLUSION: The detection rate of tagged insects by harmonic radar systems is high enough to track the walking path of pests through low row crops such as potato, tall row crops such as corn or tall but well‐separated trees of orchard‐type crops by adapting the scanning procedure to the vegetative architecture. Copyright © 2010 Crown in the right of Canada. Published by JohnWiley & Sons, Ltd     

野生雉鸡求偶行为与繁殖观察

在吉林省白城马场卧地来窝铺北荒漠草原与农田库泡交接地带,采用直观法对雉鸡求偶行为与繁殖进行了观察。结果表明,野生雉鸡繁殖求偶期种群仅限3~5只雌鸟和1只雄鸟组成,成一雄多雌结构;每窝产卵6~22枚,雌鸟产卵后独自承担孵化任务,孵化期21~24 d,幼鸟出壳即能随亲鸟觅食或隐匿于草丛中;繁殖季节食大量昆虫,以增加动物性蛋白,其它季节以植物嫩芽和谷物种实为主。     

土壤中砷的来源及迁移释放影响因素研究进展

砷是一种高致癌风险的类金属,自然环境中高砷(As)含量可对人类和生态系统构成直接的健康威胁。研究自然环境中砷的来源、存在形式及影响因素有助于进一步理解环境中砷的迁移转化规律,降低人体摄入砷的风险。对文献的分析表明,铁锰氧化物矿物的还原性溶解、黄铁矿及其他硫化物矿物的氧化溶解、铝氢氧化物表面的砷还原、有机质抑制砷吸附以及Eh降低和pH升高是造成砷向环境迁移的主要原因。本文综述了环境中砷的来源及其向环境迁移的多种影响因素,分析了这些因素与砷之间的作用机制,以期为加强砷污染治理提供科学依据。     

不同缢蛏群体应对高盐养殖环境的潜沙和摄食响应能力

为研究缢蛏(Sinonovacula constricta)生态行为应对高盐养殖环境的响应能力,以2个缢蛏群体(“申浙一号”群体SZSC和自然群体ZRSC)为实验对象,研究了不同盐度(20、24、28和32)对缢蛏群体潜沙行为、摄食生理的影响。对比2个群体潜沙指标和摄食率(FR)的差异,其中,潜沙行为实验设置盐度应激组(缢蛏从暂养池取出放进各盐度组开始实验)和胁迫组(缢蛏在各盐度条件下胁迫24 h后开始实验)。结果显示,SZSC的120 h半致死盐度为34.04,ZRSC的120 h半致死盐度为32.04。应激组中,SZSC的半数潜沙时间(BT50)显著大于ZRSC (P<0.05),盐度为24时,SZSC的BT50为4.2 min,显著低于盐度为28和32时的BT50;盐度为32时,SZSC潜沙深度分布更集中,潜沙率为88.33%,显著高于ZRSC(P<0.05)。而在胁迫组,SZSC中BT50显著低于ZRSC,潜沙率显著大于ZRSC (P<0.05)。摄食生理上,除对照组外,SZSC的FR均显著大于ZRSC(P<0.05),SZSC的FR在盐度为24时达到最大值[89.54 mL/(g·h)],显著大于其他盐度组(P<0.05)。研究表明,2个群体的生态行为均会受到盐度的影响,盐度越高,应激反应越强烈,其中,SZSC对高盐环境具有较好的耐受性。本研究从生态行为水平评估了2个缢蛏群体对高盐环境的耐受性,揭示了高盐养殖环境下缢蛏在底泥中的垂直分布情况和摄食能力,研究结果为进一步开展缢蛏耐高盐新品系的选育提供了理论参考。