Larval instars of the ant Strumigenys solifontis Brown (Hymenoptera: Formicidae): the fallacy of size distribution

Larval instars of the myrmicine ant Strumigenys solifontis Brown were determined by measuring the head width under a stereomicroscope and examining the morphology, especially chaetotaxy, by light microscopy and scanning electron microscopy. This study found that the larval stage consisted of four instars, but the first and second instars were not distinguishable by their head widths. However, the four instars could be discriminated clearly by a combination of size measurement and observations on the chaetotaxy. Within a population, there are few larvae in the first instar because of its short period (only 1–2 days before moulting into the second instar) and the low oviposition rate of the queen. Therefore, the first-instar larva needs to be collected separately from other instars so that it is not missed.     

The developmental sequence of Argulus foliaceus (Crustacea: Branchiura)

We describe and illustrate the complete development of Argulus foliaceus L. A metanauplius is followed by nine juvenile stages. Eggs were detected in the thorax of the female at the 11th stage. Comparisons are made between the development of A. foliaceus and the other freshwater species of Argulus currently found in the UK.     

Larval stages of 17 rare and poorly known British hoverflies (Diptera: Syrphidae)

Third stage larvae of three species of phytophagous (Portevina maculata, Cheilosia albitarsis and C. antiqua), thirteen species of saprophagous (Callicera aurata, Brachyopa bicolor, B. insensilis, B. pilosa, Hammerschmidtia ferruginea, Myolepta potens, Brachypalpus laphriformis, Caliprobola speciosa, Criorhina berberina, C. floccosa, C. ranunculi, Pocota personata and Xylota tarda) and one possibly predatory species (Microdon devius) of Syrphidae are described. Most of the saprophagous species breed in dead wood and many are European rarities. Nine of the 17 species described are included in the British Red Data Books: 2. Insects (Shirt, 1987). For the larva of each species, recognition features and breeding sites are described.     

Description of the first larval stage of Polycheles typhlops (Decapoda: Eryonidea: Polychelidae)

The first larval stage of the deep-sea lobster Polycheles typhlops is described for the first time from laboratory-reared material. This is the earliest stage known of the Decapoda infraorder Eryonidea, and the first stage ever obtained in the laboratory. The first larva of P. typhlops presents well-developed and chelated pereiopods I and II; the abdomen is very small and not well segmented; the pleopods and uropods are represented as small buds. Larval features of the first stage of P. typhlops are compared with other known eryoneicid forms described in the literature, especially with specimens in early developmental stages taken from plankton samples.     

中华绒螯蟹Eriocheir sinensis幼体丝状细菌的扫描电镜观察

应用扫描电间对中华绒螯蟹幼体附着的丝状细菌进行了详细的观察，结果表明，丝状细菌只附生于幼体表面，没有明显伸入体内的结构，丝状细菌行裂殖生殖，生长繁殖所需营养直接摄取自水环境，并对其危害性以及防治等方面进行了探讨。     

菲(PHE)短期暴露对斑马鱼(Branchydanio rerio)繁殖行为及产卵、受精、孵化和仔鱼死亡率的影响

研究了菲(PHE)短期暴露对斑马鱼(Branchydanio rerio)繁殖行为及其产卵量、受精率、孵化率和仔鱼死亡率的影响.将性成熟的斑马鱼分别暴露于PHE质量浓度ρ(PHE)为0、0.05、0.5、5、50μg.L-1的水中7 d后,将其配对进行繁殖,录制配对次日光照开始0.5 h内的繁殖行为,统计产卵量、受精率、受精卵3 d内的孵化率以及仔鱼7 d内的死亡率.与对照组相比,高ρ(PHE)(>0.5μg.L-1)对斑马鱼的繁殖行为抑制作用显著(P<0.05),而低ρ(PHE)(≤0.5μg.L-1)对斑马鱼繁殖行为的影响较为微弱(P>0.05).ρ(PHE)>0.05μg.L-1的能够显著降低斑马鱼的产卵量和受精率(P<0.01).PHE对斑马鱼孵化率的影响,表现出低ρ(PHE)促进卵的孵化,但这种作用随着ρ(PHE)的升高而逐渐降低,高ρ(PHE)反而抑制卵的孵化.ρ(PHE)对仔鱼死亡率的影响,则没有表现出明显的相关性.     

弓斑东方仔稚鱼形态特征的观察

描述了弓斑东方仔稚鱼前期、仔鱼期和稚鱼期各发育阶段的形态特征．初孵仔鱼全长３．１２～３．３８ｍｍ．９～１０ｄ卵黄囊被吸收而消失．１５ｄ后稚鱼的器官分化完善．２４～２６ｄ稚鱼的外部形态与成体相似，全长达１０．６０～１３．５０ｍｍ．以上观察为弓斑东方的人工育苗和规模化生产提供了必要的生物学资料．     

家蝇幼虫对糖化饲料转化利用的研究

测定了家蝇幼虫对糖化饲料的转化利用情况。通过对幼虫生物量的比较，筛选出了糖化处理饲料的优化方案为：加入糖化酶糖化，用量为０．１２５ｇ／５０ｇ麦麸，糖化时间为零，饲料中加入糖化酶可提高幼虫生物量、饲料效率、饲料效率、粗蛋白及粗脂肪的转化率。初步估算了用糖化酶糖化处理饲料的经济效益。     

青石斑鱼Epinephelus awoara仔、稚、幼鱼日龄和形态、生长发育的研究

本文根据青石斑鱼仔、稚鱼形态变化划分为前仔鱼期、后仔鱼期、稚鱼期、幼鱼期。背、腹棘的显著伸长是石斑鱼形态发育过程中的一个典型特征。背棘、腹棘长短与仔鱼全长有明显关系。背棘和腹棘比值近似1:1。仔稚鱼全长和体重两者呈幂函数相关。在整个仔、稚、幼鱼日龄生长中可分为三个阶段,第一阶段为15日龄前的仔鱼阶段,第二阶段为40日龄前的仔稚鱼阶段,第三阶段为60日龄前的稚幼鱼阶段。各生长阶段均伴随着一个危险期。导致各危险期的主要原因是(1)饵料,(2)变态,(3)自残。对策是(1)确保适时、适口饵料供应,(2)防止水质恶化和饵料营养缺乏,(3)勤分苗和充分投饵。在生长发育中,石斑鱼个体大小差异显著,导致此现象出现是因先天性和后天性二个方面造成。