4种不同生境的蟹类金属硫蛋白cDNA的克隆与比较

利用Carcinus maenas金属硫蛋白氨基酸序列资料，用全简并引物从鳃组织总RNA中扩增并克隆了首个甲壳类金属硫蛋白cDNA片段序列，3'-RACE获得了其编码区全长cDNA。之后，用部分简并的引物扩增并克隆了其它3种国内常见蟹类的金属硫蛋白cDNA编码区全长序列。序列分析结果表明，几种蟹的金属硫蛋白cDNA序列存在差异，推知的氨基酸序列也不完全相同，比较不同蟹的cDNA和氨基酸序列数据不能证明不同生态环境对金属硫蛋白的分子进化起重要作用。图4表1参15     

上海松江泖港地区蟹种养殖对水质的影响

为了探究河蟹蟹种养殖模式对水环境的影响,于2012年6-10月,对上海松江泖港地区蟹种池塘和水源的水质进行了监测.结果表明,在整个养殖周期中,蟹种池CODMn不断增长,水源水的变化趋势为先增后减.在多数时段,水源水亚硝酸盐质量浓度高于蟹种池,但6月26日蟹种池反而显著高于水源水(p＜0.05).在整个监测过程中,水源水硝酸盐质量浓度均显著高于蟹种养殖池(p＜0.05).养殖前期,水源水磷酸盐质量浓度高于蟹种池;养殖后期蟹种池高于水源水,但均无显著差异(p＞0.05).台风过境后,水源水氨氮质量浓度达2.21 mg/L,磷酸盐质量浓度达0.467 mg/L,表明农田化肥水和地表径流可能是导致水源水体富营养化的重要原因.     

螃蟹活动对闽江河口互花米草沼泽湿地土壤温室气体排放通量的影响

于2015年1月（冬季）、4月（春季）、6月（夏季）和9月（秋季）,以闽江河口互花米草沼泽湿地为研究区,采用静态箱与气相色谱结合的方法,研究螃蟹对湿地土壤CO₂、CH₄和N₂O排放通量及综合增温潜势的影响。研究表明：温室气体排放季节变化较为显著,CO₂、CH₄排放通量最大值均出现在夏季,N₂O排放通量最大值出现在秋季,CO₂、CH₄和N₂O排放通量最小值均出现在春季。与无螃蟹组相比,高潮滩和中潮滩螃蟹组CO₂、CH₄和N₂O排放通量均值都增大,其中高潮滩螃蟹组CO₂、CH₄和N₂O排放通量依次增大了46.36%、66.67%和69.66%,中潮滩螃蟹组CO₂、CH₄和N₂O排放通量依次增大了53.57%、142.97%、73.08%。相关性分析结果表明：土壤CO₂排放通量与土壤温度显著正相关（n=96,p＜0.05）,CH₄和N₂O排放通量与土壤温度显著正相关（n=96,p＜0.01）;N₂O排放通量与土壤pH显著正相关（n=96,p＜0.01）,与土壤含水量显著正相关（n=96,p＜0.05）。综上所述,螃蟹活动对闽江河口互花米草沼泽湿地土壤的干扰促进了温室气体的排放,为有效调节湿地碳、氮固持作用和湿地生态系统科学管理提供了参考。     

Modulations in Protein Metabolism of Oziotelphusa Senex Senex During Cypermethrin Intoxication

Cypermethrin induced significant alterations in protein metabolic profiles in the central nervous system (CNS) and pedipalpal muscle (PM) of crab, Oziotelphusa senex senex, following ambient exposure. While total and soluble proteins decreased in CNS and PM, free amino acids, protease, alanine and aspartate aminotransferase (AlAT and AAT) were elevated at 24 h after exposure. These results thus confirm the prevailing protein hydrolysis and transamination in these tissues of crab, as a consequence of cypermethrin intoxication. Restoration of normalcy by 48 h demonstrates the importance of these metabolic events in counteracting the effects of cypermethrin. the results also suggests the safer utilization potential and ecological compatibility of cypermethrin.     

Temporal constraints and female preference for burrow width in the fiddler crab, <Emphasis Type="Italic">Uca mjoebergi</Emphasis>

We studied sampling behaviour and mate choice in the fiddler crab Uca mjoebergi. Once a female selects a mate, she copulates in his burrow and remains there until releasing her aquatic larvae. U. mjoebergi occurs in habitats that are inundated only by the highest amplitude spring tides. Females can only release their larvae during these tides, and release before or after will result in complete failure of reproductive effort. Matings occur over a 5-day period near the end of neap tides. Our results suggest that within the mating period, females adjust their larval developmental rates by selecting specific burrows in which to incubate their clutches. We found that at the start of the mating period, females chose larger males as mates. Since male size was positively correlated to burrow width, females were selecting wide burrows and effectively incubating at lower temperatures. This would slow down the developmental rates of larvae. In contrast, females that mated late in the mating period selectively chose small males. By incubating in narrower, warmer burrows, these females may increase the developmental rates of larvae. We propose that females are selecting burrows to influence incubation rate and ensure timely release of their larvae. Female U. mjoebergi appear to adjust their preference for the direct benefits of mate choice to increase their reproductive success.     

Bridging information domains to improve ecological understanding of biological invasions in a marine ecosystem

We devised a practical method for integrating information on 2 marine invasive species using 3 different approaches: standardized ecological monitoring, online-reporting databases, and surveys of anglers and crabbers. Focusing on 2 recently introduced species with different characteristics, the Asian shore crab (Hemigrapsus sanguineus) and Chinese mitten crab (Eriocheir sinensis), in the Hudson-Raritan watershed of New York and New Jersey, we used sensitivity analyses to explore the relative contribution of each information source to knowledge of species abundance and distribution. All 3 information sources contributed something unique to understanding abundance and distribution of the introduced crabs. Online and survey data on Asian shore crabs significantly affected predictions of abundance, whereas monitoring data did not. When survey data were omitted, abundance estimates were unchanged over time, but when they were included, the model predicted an increased abundance in 2012. All 3 data sets for the Asian shore crab significantly affected estimates of species coverage; surveys had the biggest influence, increasing range size by 4097.25 km². For the catadromous Chinese mitten crab, ecological monitoring data collected in freshwater shortly after the original sighting significantly shaped model estimates for abundance and documented the establishment phase of the mitten crab in an area outside the spatial scope of the surveyed resource users. However, the survey data significantly enlarged mitten crab range-size estimates by 6498.01 km². By demonstrating that data integration produced an image of the invasion process that would not have emerged had we used any 1 method individually, model results provide evidence for the advantages of an interdisciplinary approach.     

Alterations in Carbohydrate Metabolism in Selected Tissues of Crab, Oziotelphusa Senex Senex (Fabricius) Under Fenvalerate-Induced Stress

Changes in carbohydrate metabolism in hepatopancreas and muscle of the crab, Oziotelphusa senex senex exposed to a sublethal concentration (0.2 ppm) of fenvalerate, a pyrethroid insecticide, were studied. the glycogen and total carbohydrate levels decreased significantly in the tissues of crab exposed to fenvalerate. an increase in phosphorylase 'a' and decrease in aldolase activity levels suggested increased glycogenolysis, and decreased glycolysis during fenvalerate toxicity. Krebs cycle enzymes such as NAD-isocitrate dehydrogenase, succinate dehydrogenase and malate dehydrogenase were decreased, suggesting reduced mitochondrial oxidative metabolism. Glucose-6-phosphate dehydrogenase activity was increased significantly, indicating enhanced oxidation of glucose through the hexose monophosphate shunt pathway. Lactate dehydrogenase activity was elevated indicating the development of anaerobic conditions at tissue level in the stressed crab. Cytochrome C oxidase and Mg2+ ATPase activity levels were also decreased, indicating the impaired energy synthesis and prevalence of energy crisis. These results suggest that fenvalerate has a profound effect on the glucose metabolism of crab.     

Time constraints and multiple choice criteria in the sampling behaviour and mate choice of the fiddler crab,Uca annulipes

Active female sampling occurs in the fiddler crab Uca annulipes. Females sample the burrows of several males before remaining to mate in the burrow of the chosen partner. Females time larval release to coincide with the following nocturnal spring tide and must therefore leave sufficient time for embryonic development after mating. Here we show how this temporal constraint on search time affects female choosiness. We found that, at the start of the sampling period (when time constraints are minimal), females selectively sample the larger males in the population. Towards the end of the sampling period (when the temporal constraints increase the costs of sampling), females are less selective. Furthermore, we suggest that the number of males sampled (and other indices of ‘‘sampling effort’’) may not be reliable indicators of female choosiness and may not reflect the strength of female mating preferences under certain conditions. Burrow quality also emerged as an important criterion in final mate choice. Burrow structure potentially influences reproductive success, and mate acceptance based on burrow structure appears to involve a relatively invariant threshold criterion. Since there is no relationship between male size and burrow quality, females are using at least two independent criteria when choosing potential mates. We envisage mate choice as a two-stage process. First, females select which males to sample based on male size. They then decide whether or not to mate with a male based on burrow features. This sampling process explains how two unrelated variables can both predict male mating success. Received: 23 March 1995/Accepted after revision: 14 January 1996     

Inter-sexual contests in the hermit crab <Emphasis Type="Italic">Pagurus bernhardus</Emphasis>: females fight harder but males win more encounters

Contests often occur between members of the same sex when they compete for access to mates, but inter-sexual contests may occur over access to other essential resources such as food or shelter. Despite the possibility that such contests are common, most studies focus on male fighting, and very few have analysed fights between males and females. Because males and females differ physically and physiologically, fighting ability or resource-holding potential (RHP) may also be subject to inter-sexual variation. In this study, we investigate size-controlled inter-sexual contests over the ownership of empty gastropod shells in the hermit crab Pagurus bernhardus. During these fights, there are two roles, attacker and defender, and we use a fully orthogonal experimental design to compare the performance of males and females in each role, when fighting either a male or female opponent. Although females fight more intensely, male attackers have an advantage when compared to females playing the attacker role, as they are more likely to evict the defender from its shell and thus win the resource. Further, in the defender role, male defenders are subject to shorter attacks than female defenders. The differences in agonistic performance could not be attributed to differences in perceived resource value between the sexes or to differences in body or weapon size. There are clear differences in the agonistic behaviour of males and females, and this possibility should be incorporated into models of contest behaviour. In particular, evolutionarily stable strategies may be expected to vary with sex ratios.