Effects of Dual Microalgal Species Biofilms on New Zealand Black-Footed Abalone (Hailotis iris) Larval/Post-Larval Processes

Dual microalgal species biofilms with distinct amino acid characteristics were tested for their effects on abalone (Haliotis iris) initial attachment, metamorphosis, settlement, and survival. Nine microalgal species, isolated from around Auckland, New Zealand, were grown in the laboratory, and used to produce nine dual microalgal species biofilms. Abalone larvae were exposed to the different biofilm treatments and controls (no biofilms) for seven (attachment and metamorphosis) and 14 (settlement and survival) days. The larvae performed significantly better in the dual microalgal biofilms compared to controls, and some biofilms resulted in better attachment, metamorphosis, settlement, and survival than others. For example, the best-performing biofilms almost always contained cyanobacteria (Oscillatoria cf. erythrata, Anacystis cf. aeruginosa, and Schizothrix cf. calcicola), which are attributed with better nutritional values. However, the amino acid profiles did not produce a clear pattern with regard to their effects on the four larval processes. Instead, total amino acid (TAA) content was positively correlated with percentage of attachment and metamorphosis. Greater TAA contents are likely to reflect greater amounts of extra-cellular polymers within the biofilms, which are suggested to improve larval performance.     

Effects of thyroxine and thiourea on the metamorphosis of coral trout grouper Plectropomus leopardus

The contribution of the thyroid hormone to the metamorphosis of the coral trout Plectropomus leopardus was examined. Juveniles, aged 35 days, were exposed to thyroxine (T4, 0.1 p.p.m) and thiourea (TU; inhibitor of thyroid hormone synthesis, 30 p.p.m) for 13 days. All the fish in the T4-treated group had completed metamorphosis (second metamorphosis, pigmentation and resorption of fin spines) within three days after the beginning of the experiment (day 3), whereas it took 13 days for this to occur in the control fish. Moreover, the fish in the TU group had not completed metamorphosis even by day 13. Settling behavior was significantly stimulated by T4 treatment, as was the resorption of the dorsal and pelvic fin spines, the reduction of serration on the spines, and the transition of body color into an opaque reddish hue. Fish in the TU group had longer dorsal and pelvic spines, retarded pigmentation and an abnormal black coloration. These results suggest that thyroid hormone accelerates most changes during the second metamorphosis in the coral trout.     

催青环境及分段收蚁对原蚕性别调控研究

试验结果表明 ,通过改变催青环境和分段收蚁可以人工调控家蚕的性别比例。在原种催青期中高温干燥处理 ,可使原蚕品种 872和鲁玉 蚕比例分别提高 1 3 %和 2 4% ,达极显著和显著水平 ;对原蚕 795和871品种分段收蚁 ,第 1天可提高♀性比例 1 0 %～ 2 0 % ,最后一天 (第 3天 )提高 蚕比例 ,795品种最高为2 8%～ 3 6% ,达极显著水平。     

蚕食药用价值开发现状与展望

综述了目前蚕幼虫、蚕蛹、蚕蛾和蚕沙等蚕资源在食用和药用价值开发中的最新研究进展,分析了存在的问题,并对蚕资源的进一步开发进行探讨。     

油松毛虫越冬幼虫上树下树历期的预测

通过1984～1986年对越冬幼虫的系统调查数据,分别求得油松毛虫越冬幼虫上树历期约为51d;下树历期约为87d;上树高峰期为每年的3月28日～4月19日;下树高峰期为每年的10月份。并同时对越冬幼虫上树过程中的物候学进行了观察。     

不同饲料不同龄期小蚕人工饲料育比较试验

用32个蚕品种杂交形式供试,比较了新老2种稚蚕人工饲料配方的疏毛率;结果表明新配方的24 h疏毛率普遍优于老配方,差异达到极显著水平;24 h疏毛率,老配方中只有6个蚕品种超过了98%,新配方中有21个蚕品种超过了98%,增加了15个蚕品种型式,新配方明显扩大了一代杂交种杂交率检验和小蚕共育的适用蚕品种范围.从不同龄期小蚕人工饲料育与全龄桑叶育的养蚕成绩和茧丝成绩看,用人工饲料进行小蚕共育基本可行,综合考虑各方面因素,共育到2龄后再改喂桑叶或分蚕出售给农民较好.     

韩国2种夜蛾幼虫形态记述(鳞翅目)

记述了韩国夜蛾科重要害虫灰长须夜蛾Hermina tarsicrinalis (Knoch)和希饰夜蛾Pseudoips stylpha(Butler)老熟幼虫的形态特征,并提供了形态特征图.所有标本均保存在韩国江原大学校森林资源保护学科昆虫标本室.图2参5     

圆背角无齿蚌寄生变态发育的初步观察

对圆背角无齿蚌的钩介幼虫寄生变态及稚贝发育过程进行了形态学观察和比较。实验表明:在水温(19.0±1.0)℃时,钩介幼虫需要约13天的寄生变态才能从鱼体脱落。圆背角无齿蚌在变态发育过程中其外部形态、内部器官、营养源发生了较大变化:成熟的钩介幼虫仅仅可以作简单的双壳开合运动;刚脱落的稚贝外部形态与幼虫相似,但已经可以依靠斧足进行爬行,并逐渐开始滤食;稚贝经过一段时间的生长,从幼虫壳内侧长出一对新壳,形态逐渐趋向于成贝,而幼虫壳则逐渐退化为壳顶。因此,圆背角无齿蚌的变态发育包括两个明显的阶段:第一阶段为寄生变态期;第二阶段为贝壳分泌期。     

乌鳢仔鱼摄食和消化器官的发育及其选食行为

研究日龄１～２０ｄ，全长３．９～２１．０ｍｍ的乌鳢仔鱼摄食和消化器官的发育特征，仔鱼的食物组成及其选食行为。仔鱼全长５．５ｍｍ时出现颌齿和咽齿，７．５ｍｍ时出现犁齿和副蝶（骨）齿，９．４ｍｍ时出现腭齿；全长８．３３ｍｍ左右，分化出胃、肠。仔鱼孵出后第３ｄ开口摄食。仔鱼主要摄食浮游动物，主要食物随仔鱼摄食器官和消化器官的发育而变化。摄食初期（４ｄ龄）主要为小型枝角类和轮虫，但仅显示出对小型枝角类正的选择性。之后，胃肠内的食物类群增多，由选食枝角类变为选食桡足类。研究结果表明乌鳢仔鱼对食物选择性的这一变化是仔鱼本身摄食和消化器官的发育状态以及各类食物生物的相对密度等诸因素决定的。     

温室白粉虱的生物学研究

本文报道了有关温室白粉虱Trialeurodes vaporariorum Westwood的生特学特性。根据我们的初步观察,温室白粉虱的变态类型更近于完全变态,因此,其幼虫期称为“幼虫”要比“若虫”更合适。在20℃温度下完成一个世代需要33d,25℃条件下为19d。植物的生育期对产卵量的影响显著,但对从卵孵化后发育至成虫的成活率无明显影响,温室白粉虱的交尾频率在早晨与傍晚较高,扩散方向受温室灯光影响。