应用胴体重指标鉴定黄胸鼠的年龄

为完善贵州省农区主要害鼠种群年龄鉴定划分标准体系建设内容,对2002—2009年贵州省余庆、三都、息烽、关岭4个县捕获的186只黄胸鼠(雌鼠105只,雄鼠81只)胴体重数据进行统计分析,结果表明:黄胸鼠平均胴体重为(72.86±32.80)g,雌、雄鼠之间胴体重差异不显著。根据胴体重的频次分配特征,参照繁殖状况,将黄胸鼠划分为5个年龄组,制定了各年龄组的胴体重划分标准:幼年组(Ⅰ),胴体重小于或等于30.0g;亚成年组(Ⅱ),30.1～60.0g;成年Ⅰ组(Ⅲ),60.1～90.0g;成年Ⅱ组(Ⅳ),90.1～120.0g;老年组(Ⅴ),120.0g以上。不同年龄组胴体重、体重、体长、尾长、后足长、耳长之间具有极显著差异,随着种群年龄的增长而不断增加。种群年龄组成具有明显的季节变化特征。     

Survival,food consumption and growth of Norway lobster (Nephrops norvegicus) kept in laboratory conditions

Successful commercial aquaculture of crustacean species is dependent on satisfying their nutritional requirements and on producing rapidly growing and healthy animals. The results of the present study provide valuable information for feeding habits and growth of Nephrops norvegicus L., 1758) under laboratory conditions. The aim of the present study was to examine food consumption, growth and physiology of the Norway lobster N. norvegicus under laboratory conditions. N. norvegicus (15 g wet weight) were distributed into 1001 tanks consisting of five numbered compartments each. They were fed the experimental diets (frozen mussels and pellets) for a period of 6 months. A group of starved Nephrops was stocked and fasted for 8 months. Although Nephrops grew well when fed the frozen mussels diet, feeding on a dry pellet feed was unsatisfactory. The starvation group, despite the fact that showed the highest mortality (50%), exhibited a remarkable tolerance to the lack of food supply. The study offers further insight by correlating the amino acid profiles of Nephrops tail muscle with the two diets. The deviations from the mussel's diet for asparagine, alanine and glutamic acid suggest a deficiency of these amino acids in this diet. The results of the present study showed that the concentrations of free amino acids are lower in relative amount than those of protein-bound amino acids, except for arginine, proline and glycine. The present study contributes to the improvement of our knowledge on nutritional requirements of the above species.     

针毛鼠种群年龄组的划分标准及其繁殖力

为丰富国内针毛鼠的种群生态学研究资料并为其预测预报提供科学依据,利用1984-2013年贵州省余庆县、岑巩县、凯里市和雷山县的稻田与旱地耕作区鼠情监测中捕获的针毛鼠数据,对其种群年龄组的划分标准及繁殖力进行研究。结果表明：针毛鼠平均体重为（70．12±23．60）g,根据体重的频次分布特征,参照其繁殖状况,将针毛鼠种群年龄划分为5个年龄组,制定了各年龄组的体重划分标准：幼年组（Ⅰ）体重≤35．0 g,亚成年组（Ⅱ）35．1～55．0 g,成年Ⅰ组（Ⅲ）55．1～75．0 g,成年Ⅱ组（Ⅳ）75．1～95．0 g,老年组（Ⅴ）＞95．0 g。不同年龄组形态特征具有一定变化,随着种群年龄的增长而不断增加。雌鼠怀孕率和胎仔数、雄鼠睾丸下降率和繁殖指数随着种群年龄的增长而增加。成年Ⅰ组、成年Ⅱ组和老年组为该鼠的主要繁殖群体。不同季节种群年龄组成变化明显。     

Evaluating alternative rodenticides for island conservation: roof rat eradication from the San Jorge Islands, Mexico

Introduced commensal rats (Rattus spp.) are a major contributor to the extinction and endangerment of island plants and animals. The use of the toxin brodifacoum to completely eradicate rats from islands is a powerful conservation tool. However, brodifacoum is toxic to animals other than rats and on some islands its use may not be feasible without prohibitively expensive mitigation. As part of a regional conservation program, we experimentally tested brodifacoum and two less toxic rodenticides, diphacinone and cholecalciferol, in eradicating Rattus rattus from three small islands in the northern Gulf of California, Mexico. All three rodenticides were successful in eradicating rats, suggesting that the less toxic diphacinone and cholecalciferol may be useful alternatives to brodifacoum for some island eradication programs. However, the choice of rodenticide must be balanced between efficacy and the risks to non-target species. Applied field research is needed on less toxic rodenticides, as well as improving palatability of baits. This may prove invaluable in preventing extinctions and in restoring larger and more diverse island ecosystems.     

The impacts of invasive rodents on island invertebrates

The widespread invasive rodents Rattus norvegicus, R. rattus, R. exulans and Mus musculus have been implicated in the decline and extinction of hundreds of island endemic vertebrates, but their effects on island invertebrates are less well-known. Here I present the first global review of the subject, which confirms that large-bodied invertebrates are most at risk from these rodents, and that although a disproportionate number of studies (69%) are from New Zealand, rodent-invertebrate impacts are geographically widespread. Mechanisms of impact are both direct (mediated by predation) and indirect (involving intermediary species). Some studies also suggest knock-on effects on ecosystem properties, and given the diverse ecological functions of invertebrates (as detritivores, primary consumers, predators, prey and pollinators), I suggest that an understanding of the interactions between invasive rodents and invertebrates in island ecosystems is essential for effective conservation management. Currently many reported impacts are unquantified, come from uncontrolled and unreplicated designs, or rely on time-series with inadequate baseline data. In addition to basic improvements in study design, this review highlights a need for studies which investigate mechanisms of impact, or impacts across trophic levels.     

The impact of resistance on the use of second-generation anticoagulants against rats on farms in Southern England

Resistance amongst rats to second-generation anticoagulants, notably difenacoum, has been recognised since the 1970s. Although initially considered to be of practical significance, doubts were subsequently expressed that the degree of resistance was sufficient to explain ineffective rodenticide treatments. Research published elsewhere demonstrated the overriding importance of poor poisoned bait consumption, caused by the influence of certain ecological factors on rat behaviour, in reducing the effectiveness of second-generation anticoagulant treatments on farms in southern England. In this paper we consider, however, the subtle effects of resistance to anticoagulants on treatment outcome. The prevalence of resistance was increased amongst survivors of treatments and bait consumption by resistant survivors was higher than amongst susceptible survivors. The overall prevalence and degree of resistance to second-generation anticoagulants does not, however, currently represent a practical problem. Nevertheless, selection favouring increased resistance remains a long-term threat to the effectiveness of both difenacoum and bromadiolone.     

褐家鼠日食量与食物种类和光照的关系

褐家鼠(Rattus norvegicus Berkenhout)的日食量随体重的增加而增大,而日食量指数则以幼体最高。幼体(体重30—50g)每昼夜消耗小麦4.51g,黄谷11.46g、鲜玉米36.17g。亚成体(体重50—80g),耗小麦5.53g、黄谷12.98g,鲜玉米36.78g。成体(80g以上),日耗小麦7.24g、黄谷15.27g、鲜玉米49.70g。每只鼠平均年耗干粮7.14公斤。褐家鼠的日食量受光照的影响。同一年龄组的个体在全黑条件下日食量指数最高,次为自然光,全光条件下最低。     

Palatability of bird repellents to Rattus norvegicus

The palatability to captive, mostly laboratory-bred, Norway rats (Rattus norvegicus) of cereal-based baits containing 0.02 g kg-1 brodifacoum, with and without bird-repellent additives, was compared in a no-choice experimental design. Methyl anthranilate (25 g kg-1), dimethyl anthranilate (25 g kg-1) and cinnamamide (2.5 g kg-1) reduced bait consumption by the rats, but all except one rat ate enough bait to receive a lethal dose. Cinnamamide (1 g kg-1), ortho-aminoacetophenone (0.1 g kg-1) and tannic acid (20 g kg-1) did not reduce bait consumption and all rats died after eating baits. The concentration of cinnamamide palatable to rats has only a low and short-lived repellency to birds, so it does not warrant further investigation. However, ortho-aminoacetophenone and tannic acid should now be field-tested for palatability to all three rat species in New Zealand and for repellency to native New Zealand birds.