Pre-baiting for increased acceptance of zinc phosphide baits by voles: an assessment technique

During a product-performance test of 2% zinc phosphide (Zn₃P₂) steam-rolled-oat groats (11.2 kg ha⁻¹) to control voles (Microtus spp) in alfalfa (Medicago sativa), randomly located, brushed-dirt plots were used to assess broadcast distribution and removal/acceptance of placebo particles. Results showed that the Spyker® Model-75 Spreaders were calibrated adequately, with placebo baits broadcast uniformly onto plots [x ± SD = 3.5 (±2.7) groats 930 cm⁻¹]. Acceptance of the placebos by voles increased rapidly – 28% and 60% by 24 h and 48 h post-broadcast, respectively. Analyses of variance confirmed the uniformity (non-significance) of particles broadcast among enclosures/plots and the significantly greater removal/acceptance of placebos across days. This technique affords an objective decision-making tool for applicators and researchers applying Zn₃P₂ baits in field situations – an objective technique of assessing pre-bait acceptance that should improve efficacy of the rodenticide. © 1999 Society of Chemical Industry     

东方田鼠实验动物化研究进展

东方田鼠在实验动物化方面的研究经过多年的努力，已取得了一系列的进展。作者就我国在东方田鼠的分类与分布、形态、生态、实验室饲养和繁育特性、实验室营养和环境、部分生物学特性、遗传学、微生物学和寄生虫学等方面的研究进展予以了阐述，同时提出了东方田鼠实验动物化尚需近一步研究的内容。     

洞庭湖区东方田鼠对溴敌隆的敏感性

从洞庭湖防洪大堤护坡和湖滩捕捉试鼠,在实验室做无选择性摄食试验。将试鼠雌雄分开,随机分组,配制0.000 2％溴敌隆毒饵进行不同时间的攻毒试验。用SPSS进行几率单位加权回归法(Bliss法)的计算,探讨不同食毒期与对应死亡率之间的关系。结果表明,东方田鼠性别之间对溴敌隆的敏感性差异无统计学意义,故将雌雄数据合并计算,得毒力回归方程y=0.07+2.65x,LFP50、LFP98、LFP99及其95％置信限分别是0.94(0.43～1.33)、5.63(3.51～20.83) d和7.14(4.15～33.52) d。按WHO修订以致死99％敏感靶标鼠种的食毒期(LFP99)取整天数作为抗药性检验标准,洞庭湖区东方田鼠对0.000 2％的溴敌隆毒饵食毒期超过8 d存活为产生抗药性。     

Different cross-reactivity of human and rodent sera to Tula virus and Puumala virus

Tula virus (TULV) and Puumala virus (PUUV) are hantaviruses carried by the bank vole (Myodes glareolus) and European common vole (Microtus arvalis), respectively. PUUV is a causative agent of hemorrhagic fever with renal syndrome (HFRS), while TULV is thought to be apathogenic to humans. The N-terminal regions of the N proteins from TULV and PUUV were expressed and applied as enzyme-linked immunosorbent assay (ELISA) antigens. Colonized Japanese grass voles (Microtus montebelli) and BALB/c mice were used for experimental inoculation of the vole-borne hantaviruses TULV and PUUV. Voles and mice showed significant antibody production toward both viruses, but these antisera showed little cross-reactivity between TULV and PUUV in the immunofluorescence antibody assay and ELISA. In contrast, sera from patients with HFRS caused by PUUV exhibited high cross-reactivity against the TULV antigen, and sera from a natural rodent reservoir showed moderate cross-reactivity against the heterologous antigen, indicating that the antigenic cross-reactivity between TULV and PUUV differs in sera from rodents and humans.     

洞庭湖区防鼠墙对东方田鼠防治效果调查

东方田鼠（Microtus fortis Buechner）是洞庭湖区重要的害鼠种类,在数量暴发年份,在由湖滩被迫迁入农田过程中会对农作物造成毁灭性的危害,因此修筑防鼠墙以阻断迁移通路是最为有效的防治手段。为了解防鼠墙的防治效果,在2012年4月和7月分别在湖滩和对应的堤内农田进行调查。结果有防鼠墙的堤垸内农田的东方田鼠密度为0.52%,明显低于经过人工捕杀和药物灭鼠后无防鼠墙的农田1.76%（χ2=3.900,P=0.048）;迁入农田后的密度下降幅度为98.53%,明显高于无防鼠墙堤垸的86.61%（χ2=11.060,P=0.01）。充分显示了防鼠墙防治效果,因此建议大力推广。     

Efficacy and attractiveness of zinc phosphide bait in common voles (Microtus arvalis)

BACKGROUND: Minimising the concentration of active ingredient in rodenticide bait is desirable economically and for the protection of the agroecosystem. This study aimed to identify a zinc phosphide concentration that balances palatability and efficacy for common vole (Microtus arvalis Pall.) management and to compare the attractiveness of two bait carriers. RESULTS: Bait uptake of voles was reduced by 87–98% compared with plain bait when bait contained 0.4–3.2% zinc phosphide. There was an almost 50% decrease in the uptake of zinc phosphide when the zinc phosphide concentration of bait was doubled. Red dye used in commercially available bait decreased bait consumption by 10%. Daily consumption of zinc phosphide bait on days 2 to 5 was half the consumption on the first day of exposure. In bait choice tests, wheat kernels were preferred initially, but within 12 h similar amounts of wheat‐based pellets and wheat kernels were eaten. CONCLUSIONS: According to the results from the laboratory trial, a zinc phosphide concentration of 2.1% seemed to balance uptake/efficacy best and may be most appropriate for the management of common vole populations. This concentration is substantially lower than the concentration used in many registered products. A reduced concentration of active ingredient and the use of pellet bait instead of wheat which is highly attractive for birds may have advantages for agroecosystem health when applying zinc phosphide for rodent control. © Jens Jacob, Mechthild Budde and Angela Leukers, employees of the Federal Research Centre for Cultivated Plants, Germany. Printed with permission.     

东方田鼠重复感染日本血吸虫试验研究初步

本试验以1000条日本血吸虫尾蚴同时攻击感染东方田鼠洞庭湖种群和东方田鼠宁夏指名亚种进行重复感染对比试验，并在攻击后不同天数分别同时解剖相数目的两种群东方田鼠，收集其体内不同时段，不同部位的日本血吸虫童虫，比较结果证实东方田鼠对日本血吸虫具有天然的抗性，其抗性是可遗传的，不以东方田鼠的地域分布不同、生活环境的差异或传代数目的变化而有所不同，与获得必免疫无关。     

东方田鼠肺脏裂解物筛选日本血吸虫成虫噬菌体展示cDNA文库

目的寻找与东方田鼠抗性相关的血吸虫靶基因。方法以东方田鼠肺脏裂解物为探针,亲和淘洗筛选日本血吸虫成虫（44d）噬菌体展示cDNA文库。三轮筛选后．随机挑取76个阳性噬菌体克隆进行序列测定及生物信息学分析。结果共获得了13个有效EST序列,其中8条EST序列与已知基因或表达序列标签同源,5个EST序列与已知基因或表达序列标签均无同源性,为新的表达序列标签。功能预测结果显示．这13个有效EST编码蛋白主要与血吸虫基因表达调控及蛋白质加工修饰相关。结论东方田鼠直接或间接地影响血吸虫基因表达,进而影响血吸虫的发育,可能是东方田鼠具有抗血吸虫特性的一个重要分子机理。     

Responses of a small mammal community to heterogeneity along forest-old-field edges

Despite the importance of edges effects in ecological systems, the causes and consequences of animal responses to habitat edges are largely unknown. We used three years of live-trapping and measures of the plant community around trap stations to explore the responses of white-footed mice (Peromyscus leucopus), meadow voles (Microtus pennsylvanicus), and short-tailed shrews (Blarina brevicauda) to forest-field edges in upstate New York. We found that capture probabilities of voles were highest in grass- and forb-dominated micro-habitats and in old-field zones distant from the forest edge. In contrast, capture probabilities of white-footed mice were highest in shrub-dominated microhabitats and in zones near the forest edge. Short-tailed shrews did not show strong micro- or macrohabitat associations. The responses by voles, the competitive dominant in our system, to variation along forest-field edges were more consistent across years than were those of the competitively inferior, white-footed mouse. Mice were less likely to use the old-field interiors when vole density was high than when it was low, suggesting competitive displacement of mice by voles. Finally, we found good agreement between the spatial activity patterns of mice and voles in old-fields and their impacts on patterns of survival of tree seeds and seedlings in concurrent studies. These results suggest that a dynamic interaction exists between the plant and animal communities along forest edges.     

捕食风险对东方田鼠功能反应格局的作用

植食性哺乳动物对食物斑块的选择和利用不仅取决于食物的可利用性,且与觅食环境潜存的各种风险紧密关联.捕食风险是否通过作用于动物觅食活动中的警觉影响其功能反应格局.在新鲜白三叶叶片构成的各类食物密集斑块上,测定东方田鼠觅食行为,建立功能反应模型,检验捕食风险对其功能反应格局的作用.结果发现,捕食风险能显著地延长东方田鼠的觅食决定时间,但其摄入率保持稳定,功能反应构型亦未发生改变,仍为Ⅱ型功能反应;除了对照组个体的采食时间随叶片大小增大无明显变动规律外,处理组个体的采食时间及对照组和处理组个体的处理时间、觅食中断时间均随叶片大小及口量的增大呈线性增高趋势,处理组个体的觅食中断时间明显大于对照组个体的;对照组和处理组个体的采食率均随叶片大小及口量呈非线性渐近递减趋势,但处理组个体的采食率较对照组个体的略有降低.结果揭示,在捕食风险压力下,虽然上述觅食参数变异能潜在地降低摄入率,但个体能通过改变觅食活动中各种警觉行为动作如降低嗅闻和静听监视动作的发生频次,增大视觉监视动作比重,以此缓冲捕食风险压力,维持摄入率.摄入率测定值与模型预测值的线性回归极显著,表明,功能反应模型具有良好的预测性.在可利用植物密集斑块,动物觅食活动中的警觉能缓冲捕食风险压力;动物摄入率是由植物大小调控的口量决定的,且受采食与处理食物竞争及觅食中断的制约;其功能反应仍属Ⅱ型功能反应.