不同盐度对三角帆蚌钩介幼虫、稚贝生理活动和存活的影响

对三角帆蚌钩介幼虫、不同日龄稚贝在不同盐度条件下的生理活动和存活率进行了观察和比较。以淡水组作为对照组,试验结果显示:三角帆蚌钩介幼虫在淡水组48 h存活率达90%,而盐度2条件下,2 h内即全部死亡;同龄的稚贝存活率随生理盐水浓度、实验时间的增加而逐渐降低,生理活动明显受到盐度的影响,表现为心跳频率降低,肠道蠕动减弱,斧足运动减少;随作用时间的增加,稚贝表现为心跳停止、双壳张开死亡;大日龄稚贝在同盐度下的存活率显著高于低日龄稚贝,7日龄稚贝在48 h内所有盐度组全部死亡,45日龄稚贝仅在盐度为2试验液中有90%存活,但生理活动明显低于正常淡水组,表现为心跳微弱,无肠道斧足运动。因此,认为三角帆蚌钩介幼虫对盐度较敏感,其耐受力低于稚贝,而三角帆蚌稚贝的适宜盐度要低于2。     

pH和氨氮对毛蚶稚贝生长与存活影响的初步研究

采用实验生态学方法,研究了pH和氨氮对毛蚶稚贝生长和存活的影响。结果表明:毛蚶稚贝生存的适宜pH范围为7.5~8.5,pH为8.0时生长及存活最好;氨氮浓度越高,毛蚶存活率越低;毛蚶稚贝对氨氮具有较高的耐受性,在实验条件下,毛蚶稚贝对氨氮24,48,72,96h的TLm分别为96.33,74.16,43.63,20.36mg/L,安全浓度为2.04mg/L。     

缢蛏稚贝的爬行行为及盐度对其钻穴能力的影响

缢蛏稚贝的爬行行为可分成扭动、滑行和转动三种类型,其中以扭动最典型。这些运动方式不仅有利于稚贝的钻穴生活,对其漂移行为也有一定的意义,当低盐度培养的稚贝移至较“高盐度”培养时,其钻穴能力受到明显的抑制,而较“高盐度”条件下培养的稚贝,盐度的变化对钻穴活动的影响不明显。文中还探讨了蛏苗生产应注意的问题。     

西施舌稚贝对3种微藻选择性及摄食率研究

对西施舌稚贝的摄食率及藻类选择性变化进行研究.结果表明,西施舌稚贝对直径11.2 μm四爿藻具有较高的选择性,而对云霄微型藻和牟氏角毛藻的摄食率均偏低.西施舌稚贝对四爿藻的摄食率在第5 h时达到最高值(174.928×10-5mg·h-1).当西施舌稚贝分别摄食3种藻类时,在适宜的藻类密度范围内,摄食率均随着藻类密度的增大而迅速增加,当藻类密度达到一定值后,摄食率呈下降趋势.西施舌稚贝摄食率与藻类密度之间关系适用二次多项式表示.     

温度在饲育条件下对Semisulcopira decipiens的产仔数和稚贝生长的影响

在饲育条件下研究了S．decipiens的产仔数和稚贝生长及与水温的关系。结果表明:水温在上升期和下降期,新生贝和稚贝的生长速度较快,产仔数也较多,成体贝在水温17℃-31℃时,都可以产生新生贝,以21℃-25℃时产出较多,在高温条件下,成体贝的生长速度缓慢。     

饲育条件下Semisulcospiens decipiens的生长

在饲育温度条件下研究了Ｓ．ｄｅｃｉｐｉｅｎｓ的生长和产仔数及与饲育水温的关系。结果表明水温在上升期和下降期，新生贝和稚贝的生长速度较快，产仔数也较多．成体贝在水温１１℃～２９℃时，都可产出新生贝，以１８℃～２４℃时产出较多．在高温饲育条件下，成体贝的生长速度缓慢。     

栉孔扇贝稚贝的同工酶的基因表达

2 0 0 0年 8月于辽宁省大连长海县自然海区采得 3月龄栉孔扇贝稚贝 ,利用聚丙烯酰胺凝胶电泳技术对其进行了几种同工酶的生化遗传分析 ,得到了基本稳定的酶谱 ,同时与成贝进行了比较讨论 .共记录了 10个酶位点 2 0个等位基因 .3月龄稚贝已经存在较完善的酶系统 ,能够完成基本的新陈代谢活动 .与成贝相比 ,稚贝各酶的位点数和等位基因数都较少 ,多样性也较低 .这是与其发育阶段、生活环境和新陈代谢水平相适应的     

土池人工培养菲律宾蛤仔稚贝研究

本文报道1975—1981年露天土池人工培养菲律宾蛤仔Ruditapes philippi—narum(Adams et Reeve)(简称蛤仔)的附着稚贝至蛤苗的生产性试验结果。利用涨落潮使海水进出土池每天产生往复式长时间流水比土池中关水、施肥、添水、定期换水的稚贝培养方式好,其特点是稚贝的生长快、成活率高,水温18℃以下的培养池更加显著,有效地提高单位面积产量。一般以含沙量70—90％的沙泥底质、流速30—40厘米/秒、每昼夜流水16—22小时、稚贝附着密度8万个/米~2,53亩的平均产量达39.86担;文中还说明了防除敌害的措施。     

盐度对岐脊加夫蛤幼虫与稚贝的影响

叙述盐度对岐脊加夫蛤Ｇａｆｒａｉｕｍｄｉｖａｒｉｃａｔｕｍ（Ｇｍｅｌｉｎ）幼虫及不同大小稚贝（壳长０．８～１．４ｍｍ）生长和存活的影响．水温３０±１℃时，加夫蛤幼虫阶段的适盐范围为１９．９３‰～３３．２２‰，最适盐度为２２．５９‰．其下限和上限分别为１５．９５‰和３８．５３‰，其存活率低于３０％．水温２５±１℃时，稚贝Ⅰ（壳长０．８～１ｍｍ）适盐度范围为１９．９３‰～３３．２２‰，最适盐度为２２．５９‰；较大稚贝Ⅱ（壳长１．３～１．４ｍｍ）适盐范围为１５．９５‰～３８．５３‰，最适盐度为２５．２４‰，其下限和上限分别为９．３０‰和４５．１７‰．     

温度对黑龙江河兰蛤Potamocorbula amurensis稚贝存活影响的研究

根据天津大港电厂扩建工程需要,笔者对黑龙江河兰蛤稚贝存活的各项温度指标,进行了室内研究.结果表明,兰蛤稚贝起始致死温度是随着驯化温度的变化而改变,最高起始致死温度为35.1℃,生长的周平均最高温度为28.4℃,短期暴露最高温度是32.2℃.     

Insurance-based advantage to helpers in a tropical hover wasp

The origin and maintenance of eusociality is a central problem in evolutionary biology. Eusocial groups contain individuals that forfeit their own reproduction in order to help others reproduce. In facultatively eusocial taxa, offspring can choose whether to found new nests or become helpers in their natal groups. In many facultatively eusocial insects, offspring need continuous care during development, but adult carers have life expectancies shorter than the developmental period. When a lone foundress dies, her partly reared brood are usually doomed. Here, we show that helpers in a tropical hover wasp (Liostenogaster flavolineata) have an insurance-based advantage over lone foundresses because after a helper dies, most of the brood that she has partly reared will be brought to maturity by surviving nest-mates. After some of the helpers are experimentally removed from a multi-female nest, the reduced group is left with more brood than it would normally rear. We found that larger, more valuable extra brood were reared through to maturity, but not smaller, less valuable brood. Smaller brood may be sacrificed to feed larger brood, and reduced groups probably benefited from increased short-term helper recruitment. Rearing extra brood did not increase adult mortality or brood development time.     

阑尾原位脐部造口的回结肠膀胱术

尝试根据Ｍｉｔｒｏｆａｎｏｆ原理，将阑尾不加任何处理直接从脐孔穿出，构成可控性回结肠膀胱的排出管道。方法：选取末段回肠１５ｃｍ和盲肠升结肠２０ｃｍ，保留阑尾。沿肠系膜对侧缘纵行劈开肠管，远近端对折缝合形成囊袋。双侧输尿管与囊袋以粘膜下隧道法吻合，阑尾末端开放，并直接从脐部戳孔引出固定，形成可控性回结肠膀胱。结果：８例患者术后随访１０～３０个月，回结肠膀胱脐部阑尾排出道控水能力满意，患者自行插管排尿方便容易，平均每次导尿量３００～５００ｍＬ，回结肠膀胱内压１９６１４～４４１３２Ｐａ，无输尿管返流或积水及其它明显并发症。结论：不加任何处理的阑尾原位脐部造口的回结肠膀胱术，手术简便，控尿可靠，自我插管方便，为膀胱全切除术后尿流改道病人提供了较为理想的生活质量     

Escalation of a coevolutionary arms race through host rejection of brood parasitic young

Cuckoo nestlings that evict all other young from the nest soon after hatching impose a high reproductive cost on their hosts. In defence, hosts have coevolved strategies to prevent brood parasitism. Puzzlingly, they do not extend beyond the egg stage. Thus, hosts adept at recognizing foreign eggs remain vulnerable to exploitation by cuckoo nestlings. Here we show that the breach of host egg defences by cuckoos creates a new stage in the coevolutionary cycle. We found that defences used during the egg-laying period by host superb fairy-wrens (Malurus cyaneus) are easily evaded by the Horsfield's bronze-cuckoo (Chrysococcyx basalis), a specialist fairy-wren brood parasite. However, although hosts never deserted their own broods, they later abandoned 40% of nests containing a lone Horsfield's bronze-cuckoo nestling, and 100% of nests with a lone shining bronze-cuckoo nestling (Chrysococcyx lucidus), an occasional fairy-wren brood parasite. Our experiments demonstrate that host discrimination against evictor-cuckoo nestlings is possible, and suggest that it has selected for the evolution of nestling mimicry in bronze-cuckoos.     

半夏栽培试验

本试验用半夏种子、珠芽、块茎进行盆栽和田间播种.种子繁殖当年块茎重0.1～0.5克;珠芽繁殖当年块茎重0.45～0.6克;一年生块茎繁殖,当年块茎重0.75～1.28克,三年生块茎平均重1.86克.     

A brood parasitic catfish of mouthbrooding cichlid fishes in Lake Tanganyika

Brood parasitism, where a brood of the parasitic species is fostered by the parents of another species, is well known among birds. In most cases, such offspring show a complete reliance upon their host parents for food, protection and warmth until their independence. In other vertebrate groups, however, such total dependence upon a host species is unknown. I report here the first example of true brood parasitic behaviour discovered among fishes. In Lake Tanganyika, an endemic mochokid catfish, Synodontis multipunctatus Boulenger, is a brood parasite of mouthbrooding fishes of the family Cichlidae. The eggs of the catfish are incubated in the mouths of any of several host species together with the host's eggs, but hatch earlier. Following absorption of their yolk sacs, the catfish fry feed upon the fry of the host while still in its mouth. Thus the early stages of development of this catfish not only depend upon their hosts for food and protection, but exploit almost their entire parental investment.     

二例肝泡球蚴病的组织病变考察

报道塔城地区二例泡球蚴病肝的病理病变．组织切片显示病肝组织被无数小泡囊所取代．泡囊的角质层较厚，常呈破裂，内层的生发膜产生的小雏囊均不含原头蚴，全系不育囊．肝的基本组织，包括肝小叶、肝细胞、肝窦、胆小管等均遭受严重的破坏．在病灶中心，可见有坏死与钙化的肝组织，泡囊的周围形成肉芽炎症反应，整个病灶形成肉芽结节．肝组织里并见有些泡囊破裂，生发层浸润周围组织，产生新的小泡囊并见于病灶的纤维组织内．     

An obligate brood parasite trapped in the intraspecific arms race of its hosts

Reciprocal selection pressures often lead to close and adaptive matching of traits in coevolved species. A failure of one species to match the evolutionary trajectories of another is often attributed to evolutionary lags or to differing selection pressures across a geographic mosaic. Here we show that mismatches in adaptation of interacting species--an obligate brood parasitic duck and each of its two main hosts--are best explained by the evolutionary dynamics within the host species. Rejection of the brood parasite's eggs was common by both hosts, despite a lack of detectable cost of parasitism to the hosts. Egg rejection markedly reduced parasite fitness, but egg mimicry experiments revealed no phenotypic natural selection for more mimetic parasitic eggs. These paradoxical results were resolved by the discovery of intraspecific brood parasitism and conspecific egg rejection within the hosts themselves. The apparent arms race between species seems instead to be an incidental by-product of within-species conflict, with little recourse for evolutionary response by the parasite.     

Variation in egg size and nestling growth rate in relation to clutch size and laying sequence in great tits Parus major

The objectives of this study were to examine (1) optimal clutch size in great tits (Parus major) nesting in nest boxes; (2) variation in egg morphology and nestling growth rate with position in the laying sequence; and (3) hatching asynchrony and nestling survival as determined by infrared nest cameras. We collected data from 73 clutches in artificial nest boxes in the Zuojia Natural Preserve area in Jilin Province, China, in 2005 and 2006, using infrared cameras to match laying order to hatching order for four nests. Egg morphology and growth rate were significantly affected by clutch size and position in the laying order. Overall, egg size and growth rate increased with position in the laying order. In general, it was difficult to detect asynchronous hatching from observations alone, but data from our infrared cameras showed that early-laid eggs tended to hatch before later-laid eggs, leading to hatching asynchrony. However, females invested more into last-laid eggs and nestlings, reducing size asynchrony among the chicks and leading to higher survival rates of nestlings. Our results, therefore, provide support for the"brood survival"hypothesis rather than for the"brood reduction"hypothesis.     

蜜蜂生物节律研究进展

 生物节律主要指有机体生命活动的内在节律性。蜜蜂生物节律受到其社会性的影响,从而参与许多复杂行为的调控。与果蝇相比,蜜蜂的生物节律与哺乳动物更相似。工蜂和蜂王的生物节律表现出高度的可塑性。例如,工蜂的昼夜节律受其劳动分工形式的调控,并通过与幼蜂的直接接触来调节,哺育蜂昼夜照料幼虫,在行为或时钟基因表达方面没有昼夜节律变化。从蜜蜂的社会性、蜜蜂生物节律产生的分子机制、神经基础、研究方法、可塑性、蜜蜂的睡眠等方面综述了蜜蜂生物节律的研究进展。