遗传变异与雄蜂生殖力的关系

<正>一、雄蜂生殖生物学研究概述精子形成发生在雄蜂幼虫期后期和预蛹期，精子分化发生在蛹期。精子形成始于胚胎形成和精巢的发育。精巢由精小管组成，精小管中充满初级精原细胞或未分化的生殖细胞。在幼虫发育的最后阶段（第5日龄），初级精原细胞经历4次有丝分裂形成16个次级精原细胞。次级精原细胞经历一系列有丝分裂成为初级精母细胞。从幼虫期后期到预蛹期，精子形成包含两轮减数分裂。第一次减数分裂发生在幼虫期后期，第二次减数分裂发生在预蛹期。     

桑瘿蚊防治技术研究

在室内进行的药剂处理土壤试验,在蛹期处理以50％辛硫磷和80％敌敌畏,折合每亩用药0.6kg,防效均达90％左右,但在老熟幼虫期处理效果不理想。药剂喷梢试验结果,在初孵至幼龄幼虫期以敌敌畏、辛硫磷或乐果1500倍液喷梢均有较好防效(38～58％),但在低龄虫后用药,效果明显下降。一个代次防治二次用药优于一次用药。综合防治中试结果,全年综合虫情指数可从37％控制到8％以下。     

意种工蜂发育情况探讨

蜜蜂属完全变态昆虫,不论蜂王、工蜂或雄蜂,都要经历三个过程(孵化、化蛹、羽化)和四型虫态(卵、幼虫、蛹、成虫)。其发育历期,记载不一,现以意种工蜂为制,谈两个问题:一、书上记载情况纵览蜂书,记载一致者有三项:1.卵期3天;2.产卵后第9天封盖;3.从产卵至出房计21天。记载不同者,可归纳为六点:1.幼虫期6天,蛹期12天。2.幼虫期7天,蛹期11天。3.幼虫期9天,蛹期9天。4.幼虫和作茧、休眠期10天,蛹期8天。     

中华蜜蜂和意大利蜜蜂工蜂幼虫和蛹呼吸代谢的研究

为了比较研究中华蜜蜂和意大利蜜蜂工蜂幼虫和蛹的呼吸代谢,为蜜蜂生理学、生态学、能量学及饲养管理学提供理论指导。本试验用华勃式微量呼吸检压仪测定了中华蜜蜂和意大利蜜蜂工蜂幼虫期和蛹期的耗氧量、二氧化碳释放量、呼吸商及代谢率。结果显示:中华蜜蜂和意大利蜜蜂工蜂幼虫期和蛹期的耗氧量、二氧化碳释放量及代谢率的变化趋势大致相同,在预蛹期呼吸代谢较低,蜕皮时升高。中华蜜蜂幼虫期和预蛹期的呼吸商为0.838,意大利蜜蜂为0.870;中华蜜蜂蛹期的呼吸商为0.760,意大利蜜蜂为0.770。中华蜜蜂和意大利蜜蜂工蜂幼虫期的代谢率都是随体重的增加而降低,而蛹期的代谢率与则体重无明显相关性。     

应用染色体工程培育家蚕限性黄茧品种

日本蚕业约在１９１０年开始使用杂交种，杂交种强健、好养，产量高。为制杂交种，必须将原蚕的雌雄蛹分开，才能实现杂交彻底。有关雌雄分离的方法是在幼虫期或蛹期，用肉眼观察虫或蛹的生殖腺，其中最常用的是蛹期雌雄鉴别，一直沿用至今。这种方法对蛹的性腺区分，需要...     

桑飞象生物学特性及防治的初步研究

在江苏省丰县首次发现桑飞象为害桑树,并酿成严重灾害.此虫一年一代,以幼虫在土中越冬;翌年3月下旬至4月上旬在3—10厘米土层内化蛹,蛹期12—17天;4月中、下旬成虫出土上树取食桑芽和叶片,交尾后2—7天产卵在枝顶及春季剪梢口下段等处,每头雌成虫产卵44—205粒,卵期15—19天;初孵幼虫入土取食植物.用50%辛硫磷1000倍液每亩喷雾150—200斤防治效果良好.     

椹瘿蚊形态特征及生活习性研究初报

椹瘿蚊是本所1986年发现的一种桑树种子害虫。属双翅目，瘿蚊科。在陕西关中地区，一年发生一代。以幼虫寄生于雌花子房内为害。被害桑椹畸形，种子不能正常发育。幼虫老熟后弹跳入土，结茧越复、越冬。     

柞树害虫栎粉舟蛾的初步研究

栎粉舟蛾Femtoma ocypete(Bremer)是柞树的重要害虫之一。此虫在辽宁一年发生一代,以蛹在土中越冬。翌年7月中旬开始羽化,持续到8月中旬。羽化后即可交配产卵。7月下旬到8月下旬均有幼虫孵出。幼虫经6个龄期,于9月中、下旬入土化蛹。防治方法:8月中旬往柞树上喷洒0.025％浓度的“杀虫灵”农药,能杀死各龄幼虫,防治效果为90％左右,七天后养蚕无害。     

黄粉虫的饲养管理

黄粉虫，俗称面包虫，其幼虫含粗蛋白51％，粗脂肪18．5％，营养价值高，每2-3kg饲料即可生产1kg幼虫，可饲养蝎子、林蛙、鸟类等多种经济动物，经济效益较高。     

湘西土家族蜂蛹干制作方法

蜂蛹营养丰富,风味香酥嫩脆,是纯天然美味食品。近几年在湖南湘西和张家界等地,蜂蛹售价高达400元/kg,成为山里人馈赠亲朋的又一名土特产。蜂蛹一般为胡蜂、黄蜂、黑蜂或土蜂等野蜂的幼虫和蛹,在湘西山区1年可发展2~5代,采摘期在高龄幼虫至变蛹期为最宜。蜂蛹系鲜活产品,除鲜炒取食外,大部分采用干制法加工,以便于贮藏包装。1人工取蛹     

Influence of an experimental infection of Strongyloides ransomi on performance of pigs

Sixty-four pigs (average 21.8 kg live weight) were divided into 16 comparable groups of four, each based on sex and body weight, to study the effects of a single infection of Strongyloides ransomi (either 0, 5,000, 10,000 or 20,000 S. ransomi larvae/kg body weight) on performance during a 91-d trial. Final weight, weight gain and average daily gain of pigs not infected were greater (P less than .01) than those of pigs given either 5,000 or 10,000 S. ransomi larvae/kg body weight, which in turn were greater (P less than .01) than those of pigs given 20,000 S. ransomi larvae/kg body weight. Average daily gain for pigs not infected was 40% greater (P less than .01) than that of pigs given 20,000 S. ransomi larvae/kg body weight. Feed required per unit of weight gain was 44% greater for pigs given 20,000 S. ransomi larvae/kg body weight than for pigs not infected, but this difference was not significantly greater due to extreme variation within the group of infected pigs. In each of two trials, eight crossbred barrows (average 20.0 kg in trial 1 and 22.7 kg body weight in trial 2) were examined for the effects of two levels of S. ransomi infections (0 and 10,000 larvae/kg body weight) on digestion and absorption of nutrients and on N balance. Digestion coefficients for dry matter, crude protein and gross energy for pigs not infected were greater (P less than .05) than for those experimentally infected.(ABSTRACT TRUNCATED AT 250 WORDS)     

Dictyocaulus filaria: in lambs: The effect of varying single infections on subsequent larval production

The effects of varying single doses of Dictyocaulus filaria larvae on the course of infection in lambs were studied. Four 6-months-old male lambs received an infection of 100 (Group I), 150 (Group II), 200 (Group III) and 300 (Group IV) infective larvae per kg body weight per lamb. No significant differences were observed in the lenght of prepatent period or in the onset of “useful patency” in animals receiving different quanta of infections. The percentage establishment of worms in lambs decreased as infection levels increased. The mortality and the severity of the disease produced in lambs was directly related to the level of infection given. Infected lambs vioded less quantity of faeces than their uninfected healthy controls. The number of larvae per gram of faeces (LPG) was highest in animals receiving infections of 300 larvae oer kg body weight. Allowing for the greater number of abnormalities associated with higher levels of infection, a dose of 150 larvae per kg was found to be the most suitable for establishment of infection in lambs for vaccine production.     

Use of oxibendazole for control of cambendazole-resistant small strongyles in a band of ponies: a six-year study

Oxibendazole (OBZ; 10 mg/kg of body weight) was administered to ponies at 8-week intervals to control strongylosis in a breeding band of Shetland-type ponies (n = 29 to 50) from October 1978 through September 1984. A similar use of cambendazole (CBZ; 20 mg/kg of body weight) in this band of ponies during the preceding 4-year period resulted in the survival of a CBZ-resistant population (S) of small strongyles. Effectiveness of OBZ treatments was monitored by pre- and posttreatment counts of the number of strongyle eggs per gram of feces (epg) and of the number of strongyle larvae per gram of feces (lpg). For the first 4 years of the 6-year period, epg and lpg counts were determined for 3 to 5 of the OBZ treatments; during the last 2 years, counts were determined for each treatment. For the 1st year, the mean reduction in epg was 96%. During the 2nd and 3rd years, mean reductions in epg were 80% and 81%, respectively. For the 4th and 5th years, mean reductions in epg were 69% and 43%, respectively. For the 6th year, the mean reduction in epg was 37%. Statistical analyses of the epg data, using the linear plateau method, indicated a significant increase in residual (surviving) strongyle infections after the periodic OBZ treatments, with a mean annual increase in survival of 10.3% for the 6 years. Changes in lpg were variable, but an overall loss of effectiveness of the OBZ treatments was evident. Only infective larvae of small strongyles were observed in the cultures; larvae of 2 species of large strongyles, Strongylus vulgaris and Strongylus edentatus, were conspicuously absent.(ABSTRACT TRUNCATED AT 250 WORDS)     

家蚕新品种粤蚕6号(丰9·春5×湘A·研7)的选育

“粤蚕6号”是采用杂交方法选育、组配的家蚕夏秋用四元杂交种。新品种易繁易养,综合经济性状优良:生命力与“两广二号”相当;茧层量比“两广二号”提高13.23%,万蚕收茧量15.545 kg,万蚕茧层量3.447 kg;茧丝长1 019 m,解舒率75.68%,解舒丝长771.3 m,茧丝纤度2.603 dtex,洁净93.38分。     

优质高产桑树新品种川7431的区域性鉴定及农村生产试验

以苍溪49号×6031人工杂交桑树种子为材料,采用秋水仙碱和60Co-γ射线复合诱变,从诱变群体中选择出优良单株培育成优质、高产桑树新品种川7431。经四川省桑品种区域性鉴定和农村生产试验表明,新品种川7431具有生长势旺、秋叶硬化迟、叶片大而厚、节间密、高产、优质、遗传性状稳定等特点,全年平均产叶量33 034.25 kg/hm2,比对照品种湖桑32号增产20.26%。用该品种桑叶养蚕的试验成绩为:万蚕收茧量19.56 kg,万蚕茧层量4.61 kg,5龄50 kg桑收茧量3.75 kg,分别比对照品种湖桑32号提高10.37%、10.43%、8.32%。新品种适合在四川省的平坝、丘陵,特别是容易发生干旱的蚕区栽植。     

优质高产桑树新品种“川桑98-1”的育成

以激光诱变选出的优良单株台激761、激7681和丰产型鲁桑品种湘7920为亲本,采用杂交育种方法,育成了优质、高产桑树新品种川桑98-1。该品种在四川省桑品种区域试验和农村生产试验中均表现出丰产性好的特点:枝条直立,节距密,发条能力强,生长势旺;全年平均产叶量为35 311.62 kg/hm2,比对照品种湖桑32号增产20.25%,并且秋叶硬化迟。该品种的养蚕试验成绩为万蚕产茧量18.38 kg、万蚕茧层量4.475 kg、4~5龄50 kg桑产茧量3.65 kg,分别比对照品种湖桑32号提高6.98%、6.04%、11.96%。新品种已通过四川省农作物品种审定,适于在四川盆地主要蚕区栽植。     

家蚕限性褐圆斑品种实用化研究初报

以优良现行家蚕品种夏芳、871、317、873改良中系限性褐圆斑LC310,回交4代,再用顶交法测定配合力,组配了一对限性褐圆斑实用品种夏芳限×LN010。该品种中系为限性普斑,日系为限性褐圆斑,杂交种为限性褐圆斑,易于进行早期雌雄鉴别。鉴定结果表明其一代杂交种生产性能良好,雄蚕茧全茧量2.00 g,茧层量0.536 g,茧层率26.77%,万蚕收茧量18.99 kg,万蚕茧层量5.07 kg,死笼率1.47%;茧丝长1 324.58 m,解舒丝长1 018.86 m,解舒率76.92%,鲜茧出丝率22.91%。     

Evaluation of Duddingtonia flagrans in reducing infective larvae of Haemonchus contortus in feces of sheep.

Consequences of nematode infections due to Haemonchus contortus are a serious constraint for the sheep industry worldwide. Development of anthelmintic resistance and increasing concern about the impact of anthelmintic use dictate the need of alternative control. Such an alternative is using the nematode trapping fungus Duddingtonia flagrans to reduce infective larvae levels on pasture. Two trials were conducted to determine the effect of D. flagrans in reducing infective larvae (predominantly H. contortus) in feces. The first trial determined the dose effect of D. flagrans in reducing infective larvae in feces. Eighteen ewes were dewormed to remove existing infections and randomly assigned to six treatment groups: 5 x 10(4), 1 x 10(5), 2.5 x 10(5), 5 x 10(5), 1 x 10(6) or no (control) spores of D. flagrans per kg of body weight mixed in their feed for 7 days. Fecal samples were collected daily from these and from infected donor ewes. Feces from individual-treated ewes were mixed with equal amounts of donor ewe feces, theoretically approximating oral dose spore concentrations of 2.5 x 10(4), 5 x 10(4), 1.25 x 10(5), 2.5 x 10(5), 5 x 10(5) and no spores, and were cultured. Across dosages and during the 7 days of fungus feeding, percent reduction of infective larvae ranged from 76.6 to 100.0%. The second trial determined the effect of D. flagrans at the dose of 10(5) spores per kg body weight on reducing infective larvae in feces from naturally infected lambs. Twenty lambs were randomly assigned to either treatment or control groups based on fecal egg count. Treatment lambs were fed spores mixed in feed for 7 days. Feces were collected daily and cultured. During the 7 days of fungus feeding, the percent reduction of infective larvae ranged from 82.8 to 99.7%. Results of these trials demonstrated that the nematode trapping fungus D. flagrans was highly effective in reducing infective larvae in sheep feces and should be considered as a biological control agent for integrated nematode control programs.     

Efficacy of oxfendazole against inhibited larvae of Ostertagia ostertagi in naturally infected calves in the southern USA

Forty yearling calves were assigned to four equal groups; three of the groups were treated with oxfendazole at dose rates of 6.75 mg/kg, 4.50 mg/kg, or 2.25 mg/kg bodyweight while the fourth group served as an untreated control. The calves were native to north-east Mississippi, USA, and harboured natural infections of gastrointestinal nematodes. The study was conducted during July when inhibited early fourth-stage larvae may be found in large numbers after their acquisition in the spring. The calves were maintained in separate groups on concrete-floored pens for 17 days before the intraruminal administration of oxfendazole. Seven days after treatment, the calves were slaughtered and the gastrointestinal parasites counted. At all the dose rates examined oxfendazole exhibited an efficacy of at least 99.4 per cent against adults of Haemonchus placei, Trichostrongylus axei, Bunostomum phlebotomum, Cooperia species, T colubriformis, Oesophagostomum radiatum, and Trichuris ovis. The efficacy against adult Ostertagia ostertagi was at least 99.4 per cent at dose rates of 6.75 and 4.50 mg/kg bodyweight, but decreased to 93.7 per cent at 2.25 mg/kg. The efficacy of oxfendazole against inhibited larvae of O ostertagi decreased with dose rate from 78.8 per cent at 6.75 mg/kg, to 58.9 per cent at 4.50 mg/kg and 20.3 per cent at 2.25 mg/kg bodyweight.