Effect of nitrite on larval development of giant river prawn Macrobrachium rosenbergii

The effects of ambient nitrite concentrations on larval development of giant river prawn Macrobrachium rosenbergii were evaluated. The trials were conducted in two phases: phase 1, larvae from stages I through VIII and phase 2, larvae from stage VIII until post-larvae. In both phases larvae were kept in water with nitrite (NO₂-N) concentrations of 0, 2, 4, 8 and 16 mg/L. Oxygen consumption was analyzed for larvae in stage II at nitrite concentrations of 0, 4, and 8 mg/L. Survival, weight gain, larval stage index and metamorphosis rate decreased linearly with increasing ambient nitrite concentration. However, there was no significant difference between larvae subjected to 0 and 2 mg/L NO₂-N. In phase 1, there was total mortality at 16 mg/L NO₂-N, while in phase 2 larval development stopped at stage X in this treatment. The oxygen consumption in stage II increased significantly at NO₂-N concentration from 0 to 4 mg/L, but there was no difference between 4 and 8 mg/L NO₂-N. In conclusion, increasing ambient nitrite up to 16 mg/L NO₂-N delays larval development, reduces larval growth rate and causes mortality, whereas no significant effect occurs for levels below 2 mg/L NO₂-N. However, the establishment of a general safe level of nitrite to M. rosenbergii hatchery may be difficult due to the great variability in larvae individual sensitivity.     

氨氮对罗氏沼虾幼体的影响

非离子态氨氮对罗氏沼虾幼体毒性试验结果表明，罗氏沼虾幼体２４小时半致死的ＮＨ３－Ｎ浓度值为４．１０９毫克／升左右，１００％死亡的ＮＨ３－Ｎ值为５．０６１毫克／升；４８小时ＮＨ３－Ｎ的ＬＣ５０值范围为１．０１５－２．１１２毫克／升，ＬＣ值为３．１２７毫克／升；生产池中的ＮＨ３－Ｎ值较低，对罗氏沼虾幼体的生长蜕壳没有什么明显的不利影响。     

入境旅客非法携带番石榴中实蝇幼虫的分子鉴定

[目的]探索DNA条形码技术在实蝇快速鉴定中的应用。[方法]利用DNA条形码技术和BOLD系统,选取线粒体细胞色素氧化酶I(COI)基因片段,针对截获入境旅客非法携带的番石榴中实蝇幼虫进行序列测定、比对和分析,并对培养后的成虫进行形态学分类从而验证分子分类的结果。[结果]检测的11头实蝇幼虫全部鉴定为橘小实蝇[Bactrocera dorsalis(Hendel)]。[结论]为河北出入境检疫部门初步探索DNA条形码技术在实蝇快速鉴定中的应用及提升检疫工作的时效性奠定了技术基础。     

杨柳毒蛾幼虫发生期,发生量预测预报的研究

杨毒蛾(Leucoma candida S.)、柳毒蛾(Leuccma salicis)是杨树的主要食叶害虫。我们从1984—1987年对该虫的发生期、发生量预测预报进行了初步研究。杨、柳毒蛾幼虫的发生期是在寄主杨树,展叶后的第10 d或日平均温度达到13℃以上时,开始上树取食。该虫的发生量预报可采用越冬基数调查和回归预报式两种方法,其种群数量动态预报模型所筛选出的预报因子与虫情的复相关系数都很高,模型的显著性水平也很高。经过检验及初步预报实践,效果较好。     

六星黑点木蠹蛾幼虫在核桃树上的分布规律研究

通过调查六星黑点木蠹蛾幼虫在核桃树上的分布,利用8种聚集度指标对六星黑点木蠹蛾幼虫的分布规律进行了分析.结果表明,该幼虫的空间分布格局为聚集型分布.     

海水桡足类的营养及在鱼、虾、蟹幼体培育中的应用

海水桡足类在海洋食物网和生态系统中具有重要的地位,是各种海洋经济鱼类和甲壳类的重要饵料,也是经济水产动物人工育苗阶段的优质活饵料源。研究海水桡足类营养和应用效果,对提高海水鱼、虾、蟹类幼体变态率、成活率、苗种质量和育苗成功率具有重要的意义。     

The toxic effects of pyrethroid deltamethrin on the common carp (Cyprinus carpio L.) embryos and larvae

Deltamethrin, a synthetic pyrethroid pesticide contaminating aquatic ecosystems as a pollutant, was investigated in the present study for toxic effects on embryos and larvae of common carp, Cyprinus carpio as a model. The control and five test experiments were repeated five times. The water temperature in the experimental units was kept at 24 ± 1 °C. The number of dead embryos significantly increased in response to deltamethrin concentrations 0.005, 0.05, 0.5, 5, 25, and 50 μg L⁻¹ (p<0.05 for each cases). Dose-response decreases in hatching success were recorded as 75.2, 64.6, 47.4, 26.0, 14.4, and 9.0%, respectively. The lowest concentration of deltamethrin (0.005 μg L⁻¹) produced a significantly decrease in number of dead larvae compared to control group (p<0.05). With increasing deltamethrin concentrations, the larvae exposed duration 1-48 h significantly increased the number of dead larvae (p<0.05 for each cases). The 48 h LC₅₀ values (with 95% confidence limits) of deltamethrin for common carp embryos and larvae were estimated as 0.213 (0.103-0.404) and 0.074 (0.011-0.260) μg L⁻¹, respectively. The results provide evidence that deltamethrin pollution may have an adverse effect on the reproduction and development of carp, which should be considered when this chemical is used in agricultural areas near aquatic ecosystems.     

五种环保型农药防治杨干象幼虫试验

选用35%吡虫啉悬浮剂、3%噻虫啉微囊悬浮剂、1.2%烟碱·苦参碱乳油、8%氯氰菊酯微胶囊剂、20%灭幼脲Ⅲ号悬浮剂5种环保型农药与废机油分别按1∶20、1∶30、1∶40比例混合,通过点涂法测定对杨干象幼虫的防治效果,其结果表明:5种农药与废机油的混配制剂均取得了较好的防治效果,对杨干象的致死率均大于88%;35%吡虫啉与废机油混配制剂(1∶30)防治效果最佳,校正致死率达96.2%;同种农药与废机油不同配比后,防治效果差异不显著;考虑到环保、高效、经济及防治效果等因素,筛选出的最优方案为:20%吡虫啉悬浮剂与废机油按1∶40混配。     

Whole-body concentrations of cortisol and sex steroids in white sturgeon (Acipenser transmontanus, Richardson 1836) during early development and stress response

In general little is known about hormones and the ontogeny of the stress response in the early developmental stages of chondrostean fishes and in particular of white sturgeon (Acipenser transmontanus, Richardson 1836). In this study, we measured for the first time cortisol and sex steroids (testosterone and estradiol) in eggs, larvae, post-larvae, and fry of white sturgeon by radioimmunoassay (RIA), to elucidate some endocrine aspects of its development. The cortisol, testosterone, and 17β-estradiol of maternal origin found in unfertilized eggs of white sturgeon probably regulate both growth and development of the embryo. Cortisol decreased after fertilization, whereas testosterone and 17β-estradiol did not significantly change. During the late stages of embryo development and immediately after hatching, endogenous production of cortisol and sexual steroids, respectively, occurred. Sex steroids may be physiological inducers of gonad sex differentiation in sturgeon. All steroids showed an increase 10 days post-hatch (dph), near the transition from an endogenous to an exogenous energy source. Cortisol maintained the same basal levels even after metamorphosis, whereas testosterone and 17β-estradiol declined significantly in post-larvae at 35 and 45 days post-hatch. In addition, to evaluate the ontogeny of a functional hypothalamic-pituitary-interrenal (HPI) axis, larvae and fry were submitted to acute stress. The HPI axis did not seem to be functional on the first day post-hatch, but became so from the third day post-hatch onward.     

云南省松叶蜂科幼虫分类研究——小松叶蜂属（膜翅目 广腰亚目）

描述小松叶蜂属,幼虫２种,编制了幼虫分种检索表,记载了种的寄主和地理分布。