多效唑在大型溞体内富集与释放行为

本文探讨了大型在含藻（系统Ａ）和不含藻（系统Ｂ）水体内，对￣３Ｈ多效唑的生物富集以及释放行为。用药物动力学模型分析了多效唑在大型－水体之间的转移。结果表明：在实验初期，由于大型对小球藻的摄食作用，大型在系统Ａ的生物富集系数显著大于系统Ｂ，存在生物放大作用。而在实验后期，两个系统中大型对多效唑的生物富集系数趋于相近。多效唑在大型体内的释放行为符合一级动力学过程，半衰期为６ｈ．实验结束后，多效唑在大型体内的残留量占总量的２０％。     

去势对育成期雄水貂生长发育及毛皮质量的影响

对不同d龄（55、85、115、145）去势雄水貂的生长发育及毛皮质量的研究结果表明：55d龄去势的雄水貂在打皮时（205d龄）体重和体长均极显著低于未去势者（P＜0．01）；毛皮质量有所提高，但55d龄去势的雄水貂皮张长度明显降低（P＜0．05）；说明水貂去势不宜早于85d龄．组织学研究结果表明：去势雄性水貂骺板P区软骨细胞数目较多，D区较窄，细胞肥大过程延迟,钙化及骨化速度降低；骺板宽度变化的测定表明：雄性水貂骺板融合时间在145d龄左右，55、85d龄去势雄性水貂骺板融合延迟40d以上．骺板融合的延迟虽然使55d龄去势雄性水貂挠骨长度相对于体长增加，55、85d龄去势雄性水貂挠骨长度相对于体重增加，但是并没有使骨骼绝对长度增加．115d龄以后去势对雄性水貂骺板融合没有影响．对不同日龄去势雄水貂血清睾酮水平亦进行了测定分析．     

乌鳢仔鱼生化成分变化与其行为的关系

研究了１～１６ｄ龄乌鳢仔鱼水分、Ｎａ＋、Ｋ＋、脂肪和蛋白质含量的变化及其主要摄食行为．结果表明，初孵仔鱼含水量为５０．１５％～５２．４０％，并随发育进展持续上升到８６．３５％～８６．８６％，而仔鱼干重则在第６ｄ最低．Ｎａ＋、Ｋ＋在仔鱼前期波动较大，第８ｄ后稳步上升，脂肪食量在孵出后的前４ｄ基本上保持不变，第５ｄ下降１５．８５％，第６ｄ下降３４．３８％，此后一直下降．蛋白质含量前８ｄ变化很小，第８ｄ后开始大幅上升．结合行为学观察认为，油球在仔鱼前期主要作为“浮力器官”（ｂｕｏｙａｎｃｙｏｒｇａｎ），在后期则可补偿摄入能量的不足．     

NaCl,Na2CO3胁迫下星星草根际K^＋,Na^＋,Ca^2＋的生理行为

对星星草施加25～600mmol·L－1NaCl及12．5～200mmol·L－1Na2CO3的盐胁迫处理，分析其根际K＋、Na＋、Ca2＋的生理行为．结果表明：Na2CO3对培养液中K＋、Na＋、Ca2＋活度的影响大于NaCl，其中Na2CO3使Ca2＋活度极度下降；营养液中K＋、Na＋、Ca2＋活度与星星草根中K＋、Na＋含量密切相关，其中，根中K＋、Na＋含量与营养液中Ca2＋活度和Na＋活度平方之比即（Ca2＋）／（Na＋）2之间具有一致的曲线关系，根系环境中的（Ca2＋）／（Na＋）2对植物K＋、Na＋吸收有决定性作用．星星草地上部分K＋、Na＋含量与其根中K＋、Na＋含量也相关．根（DW）中K＋在0．38～0．52mmol·g－1间可维持地上部分K＋含量基本稳定．根中Na＋含量较低时，地上部分Na＋含量随根中含量升高而平缓上升．但根中Na＋高至一定值时，地上部分Na＋转而急剧上升，提示星星草在由根向上转运K＋、Na＋的过程中有一定调控作用．     

马氏甲烷八叠球菌S－6的一个染色体区段的表达、序列分析和结构分析

用一组多克隆抗体对马氏甲烷八叠球菌（Ｍｅｔｈａｎｏｓａｒｃｉｎａｍａｚｅｉ）Ｓ－６菌株的基因组ＤＮＡ文库进行了筛选．仅选出ｐ６０Ａ克隆能对马氏甲烷八叠球菌中可发生细胞形态学变化菌株的抗血清发生阳性反应．对ｐ６０Ａ克隆的双链ＤＮＡ进行了序列分析．识别出一开式阅读框架（ｏｐｅｎｒｅａｄｉｎｇｆｒａｍｅＰ，ＯＲＦＰ）．表达的蛋白是ＯＲＦＰ编码的蛋白的３倍，并得到ＯＲＦＰ蛋白的三聚体，在ＳＤＳ－ＰＡＧＥ中表现出整体蛋白的迁移行为．同时，此表达蛋白抗１０％ＳＤＳ，６ｍｏｌ／Ｌ尿素及热处理．基因结构分析表明，ＯＲＦＰ具有与Ｍ．ｂａｒｋｒｉｍｃｒＡ有同源性的核糖体结合位点和一个与甲烷细菌启动子共有序列相似度达７７％的启动子序列．使用参照序列分析表明，由ＯＲＦＰ演绎的氨基酸序列，具有高密度的带电荷的氨基酸和占优势的β－层迭构型．对此表达蛋白作了Ｎｅｕｒｏｓｒｏｒａｃｒａｓｓａ的ｐｏｒｉｎ蛋白抗血清试验，以研究其可能功能．检验了Ｍ．ｍａｚｅｉＳ－６细胞的蔗糖梯度制备物，对此原细胞中的ＯＲＦＰ蛋白作了定位．结果表明，ＯＲＦＰ蛋白可能是一种古细菌Ｐｏｒｉｎ，其在Ｍ．ｍａｚｅｉＳ－６中的表达，可能象大肠杆菌那样与渗透压调节有关．     

海洋环境中抗生素存在与环境行为研究进展

由于抗生素的频繁使用和排放，抗生素不断排放进入水环境，表现为“持续存在”的状态，对生态环境系统造成长期、持续的环境风险，由此导致的环境污染和细菌耐药性是我国及全球都亟待解决的重大环境问题.抗生素持久性的选择压力会产生抗生素抗性基因（antibiotic resistant genes,ARGs），其在环境中的持久性残留，在菌群间的迁移、传播和扩增，比抗生素残留本身对生态环境的危害更大.随着海洋资源与环境的持续开发与利用，海洋正逐步成为抗生素和ARGs的重要储存库，海洋环境中的抗生素和ARGs对海洋生态环境和公众健康的威胁同样不容忽视.本文对海洋环境中抗生素的来源、赋存、迁移转化和生态风险等研究进行分析梳理，对海洋环境中ARGs的环境行为进行综述，以期为海洋环境中抗生素和ARGs环境行为和风险评估研究提供参考，最后对相关研究的发展趋势进行了展望.     

How reliable are behavioral cues for assessment of male mating status in polyterritorial wood warblers,Phylloscopus sibilatrix?

It has been suggested that polyterritoriality in birds, i.e. mated males defending two spatially separated territories, deceives females into accepting polygyny against their best interest. Mated males singing on secondary territories should make it difficult for new arriving females to assess the mating status of unmated and mated males advertising to females. However, there have been objections to the deception hypothesis, suggesting that differences in territorial behavior between males of different mating status may make correct assessment possible. Polyterritorial males frequently leave their secondary territory to visit the female in the primary territory, thereby revealing their mating status to females in search of mates. The aim of this study is to investigate how reliable behavioral cues are in assessing the mating status of males in polyterritorial wood warblers. Our study shows that singing activity of mated males on secondary territories and unmated males was similar in the morning, while there was a significant difference in the afternoon. Unmated males spent, on average, more time on their territories than mated males spent on their secondary territories. However, there was considerable variation in both unmated and mated males in the frequency in which they left their territories. For instance, unmated males left their territories quite frequently early in the season compared to later. Hence, females must be able to interpret singing behavior and a male leaving his territory differently depending on time of the season and time of the day in order to correctly assess the mating status of advertising males. Estimating the increase in probability of finding an unmated male by using behavioral cues showed that females could increase the probability of finding an unmated male compared to random choice with respect to mating status. The uncertainty was, however, still considerable. The most important factor affecting the probability of finding an unmated male was the proportion of mated males on secondary territories compared to unmated males. Our study suggests that presence on a territory is not a reliable cue for the assessment of male mating status in polyterritorial wood warblers.     

Analysis of the causal components of assortative mating in water striders

Field studies demonstrate that natural populations of a group of water striders (Heteroptera: Gerridae) that share a common mating system are characterized by weak assortative mating by size and by large sizes of mating males and females relative to single individuals. This study presents an experimental assessment of the components of mating that may contribute to these mating patterns. The effects of male and female body size on each of three components of mating were studied in three water strider species in the laboratory. Large females of all three species mated more frequently, copulated for longer and were guarded longer than small females. Large males mated more frequently than small males in all three species, and also guarded females for longer in the two species where the average of mate guarding was long. However, we found an antagonistic effect of male size on copulation duration: small males copulated for longer than large males in all three species. We show that the combined effects of these size biases mimic the mating patterns found in the wild, e.g. weak and variable assortative mating, and stronger and less variable size ratios of mating versus non-mating females relative to males. We suggest that the antagonistic effects of male size on copulation and guarding duration may be a key source of interpopulational variation in assortative mating and sexual selection on male size. Further, neither spatial or temporal covariation in size, nor mechanical constraints, caused the assortative mating observed here in this group of water striders. Some combination of male and female choice (either active or passive forms) of large mates and male-male exploitation competition for mates play potentially important roles in producing population level assortative mating in water striders. Received: 17 March 1995/Accepted after revision: 28 October 1995     

Trail following,speed and fractal dimension of movement in a marine prosobranch,Littorina littorea,during a mating and a non-mating season

We quantitatively studied movement behaviour in the gastropod Littorina littorea in laboratory experiments during periods of their non-mating season (November 1992) and their mating season (April–May 1993). Snails were collected in 1992 and 1993 from one boulder shore on the north west coast of Sweden. In a comparison between the two seasons (one non-mating and one mating) we measured trail complexity of unsexed snails using fractal dimesion, the degree of mucus trail following (coincidence index of marker and tracker trails) and average movement speed of marker and tracker snails. We found no differences in fractal dimension and coincidence index of trails between the two seasons. Tracker snails moved, however, significantly faster than marker snails during both seasons. This could not be explained by trackers, when locomoting, using the mucus trail deposited by the marker to increase their speed, since there was no correlation between coincidence index and tracker speed. During the mating season we also conducted trail complexity, trail following and speed experiments comparing the behaviour of males and females. There was no difference between males and females in the fractal dimension of movement, nor was there any difference between the mean speed of male and female snails, although male marker snails tended to move faster than female marker snails. Males tracking other males, females tracking other females and females tracking males followed trails about equally long distances (i.e., coincidence indices did not differ). In contrast, males following female mucus trails showed a significantly higher degree of trail following than the other sex combinations. This new finding may suggest that females of L. littorea release pheromones in their mucus trails and that males are able to identify them.     

Seasonal variation in male-female competition,cooperation and selfish hoarding in a monogamous songbird

Both cooperation and conflict between the sexes are commonplace in monogamous mating systems. However, little is known about how cooperation and competition varies seasonally in monogamous species that maintain permanent territories. We presented territorial pairs of male and female New Zealand robins (Petroica australis) with a large supply of insect prey at monthly intervals for 2 years. Behavioural observations after food presentation were then made to quantify seasonal and sexual differences in aggressive interactions over prey, prey acquisition rates, mate provisioning, offspring provisioning, selfish food hoarding and cache retrieval. Data were used to evaluate sex-specific behavioural strategies of mediating competition for food. Results showed that males aggressively excluded females from experimental food sources year-round. Females only accessed food sources when males left them unattended. Consequently, females acquired fewer prey than males. After controlling for differences in prey acquisition, both sexes consumed similar amounts of prey in the non-breeding season. Even though males aggressively excluded females from accessing food sources directly, males fed large amounts of prey to females during the breeding season. Both sexes provisioned young at similar rates. Males cached less prey than females in the breeding season but more prey than females in the non-breeding season. Females showed similar caching intensities year-round. Although males tried to defend their hoards, females frequently retrieved male-made caches. Overall, results showed that although New Zealand robins cooperate to raise offspring during the breeding season, conflict between the sexes occurs year-round. Males and females display different behavioural strategies to gain access to experimental food sources, which appear to lessen male–female competition for food and evenly distribute food resources between the sexes.     

Mating strategies of a nocturnal,desert rodent (Dipodomys spectabilis)

Summary The mating system of a nocturnal, desert rodent, the banner-tailed kangaroo rat (Dipodomys spectabilis) was studied through direct observation, live-trapping, and radiotelemetry over a 13-month period from August 1986 to August 1987. Mating behavior varied from exclusive matings between male and female neighbors to competitive mate searching and direct male competition. In summer matings and early in a November to May breeding season, males located receptive females and mated exclusively with them without disturbance from other males. As the operational sex ratio changed in favor of males, multiple males converged on an estrous female's territory and competed for access to her. However, an older, experienced male usually monopolized the matings of the same one to two close female neighbors for the entire breeding period, and females mated with the same male neighbor over several estrous cycles. Monopolization of females by neighbor males was facilitated by female relaxation of individual territorial defense. Dominant males spent considerable time in the territories of the females they monopolized before and during mating. This relaxation in territorial defense was seen in dyadic encounters in which females tolerated all males but allowed significantly more contact by neighbor than stranger males. Neighbor recognition, therefore, seems important in coordinating the mating interactions of this solitary rodent.     

Display rate by male fairy-wrens (Malurus cyaneus) during the fertile period of females has little influence on extra-pair mate choice

Empirical and theoretical studies have only recently begun to examine how females use complex multi-component displays when selecting mates. Superb fairy-wrens are well suited to the study of female choice because females have control over extra-group paternity and cuckold their mates at high rates, while males possess a variety of sexually selected traits. Available evidence suggests that females base their extra-group mate choice on the timing of male moult into breeding plumage or the onset of display. However, males continue to perform elaborate displays throughout the season, and direct most displays to females during their fertile period. We therefore conducted focal observations on fertile females to quantify the frequency of male display and used microsatellite genotyping to compare the role of display rate during the breeding season and the timing of male moult on female mate choice. We show that the addition of data on male display rate does not improve our ability to predict which males obtain extra-group paternity. The timing of male moult into breeding plumage remains the only predictor of male extra-group reproductive success. Nevertheless, we found that males displayed more to females that were unable to select extra-group mates on the basis of the timing of moult or the onset of display. This raises the possibility that there are circumstances when females use display rate to discriminate between potential extra-group sires. Overall this study supports the theoretical prediction that females are more likely to base their mate choice on reliable indicators of male quality such as fixed morphological traits and displays of endurance, in this case an early moult into breeding plumage and the performance of an elaborate display during the winter, than a flexible behavioural trait such as display rate during the breeding season. Received: 26 January 2000 / Revised: 1 August 2000 / Accepted: 26 August 2000     

Between-group encounters among bonnet macaques (<Emphasis Type="Italic">Macaca radiata</Emphasis>)

Socioecological theory suggests that between-group competition is an important factor affecting the nature of primate social relationships. Between-group encounters in macaques may involve female resource defense, male mate defense, and male resource defense. We observed between-group encounters in two groups (a forest group and a temple group) of bonnet macaques (Macaca radiata). We observed 102 encounters in 875 h of observation of the forest group (1.40 per 12-h day) and 58 encounters in 907 h of observation of the temple group (0.77 per 12-h day). Aggressive interactions between groups occurred in 32.4% and 29.3% of encounters in the forest and temple groups, respectively. Overall, we found little support for the female resource defense hypothesis. Females in both groups rarely participated aggressively in between-group encounters. We found support for the male mate defense hypothesis. For example, males of the forest group were more aggressive during encounters in the mating season than in the non-mating season. Males were also aggressive to females from their own group immediately following encounters. We also found partial support for the male resource defense hypothesis. Encounters in the forest group occurred in a feeding context more often than expected based on time budgets. Also, males in the temple group were more often aggressive in food-related encounters than in other encounters. The findings of this study suggest that socioecological models of primate social relationships need to distinguish male and female strategies during between-group encounters and integrate the resulting functional outcomes.Communicated by T. Czeschlik     

Space use and social structure in meadow voles,Microtus pennsylvanicus

Summary Free-ranging, sexually mature meadow voles (Microtus pennsylvanicus) were tracked by using radiotelemetry from June through August in Front Royal, Virginia, U.S.A. Estimates of intraspecific spacing were derived from the concurrent movements of up to 16 voles. Positions were recorded hourly for 24 h, twice per week. A total of 16 male and 15 female voles were studied during sixteen 24-h sessions.The daily ranges of males (192.3±109.7 m²) were larger and more variable than those of females (68.6±39.4 m²). Males also changed locations more frequently (Fig. 2).Adult females usually maintained territories free of other females; males overlapped considerably among themselves (Fig. 2). Males temporarily moved into the areas occupied by estrous females, indicating intrasexual competition among males for access to receptive females (Fig. 3). M. pennsylvanicus appears to be promiscuous, is socially organized into territorial, maternal-young units during the breeding season, and fits the female territorial model of population regulation.     

Sex differences in survival costs of reproduction in a promiscuous primate

In sexually promiscuous mammals, female reproductive effort is mainly expressed through gestation, lactation, and maternal care, whereas male reproductive effort is mainly manifested as mating effort. In this study, we investigated whether reproduction has significant survival costs for a seasonally breeding, sexually promiscuous species, the rhesus macaque, and whether these costs occur at different times of the year for females and males, namely in the birth and the mating season, respectively. The study was conducted with the rhesus macaque population on Cayo Santiago, Puerto Rico. Data on 7,402 births and 922 deaths over a 45-year period were analyzed. Births were concentrated between November and April, while conceptions occurred between May and October. As predicted, female mortality probability peaked in the birth season whereas male mortality probability peaked in the mating season. Furthermore, as the onset of the birth season gradually shifted over the years in relation to climatic changes, there was a concomitant shift in the seasonal peaks of male and female mortality. Taken together, our findings provide the first evidence of sex differences in the survival costs of reproduction in nonhuman primates and suggest that reproduction has significant fitness costs even in environments with abundant food and absence of predation.     

Female resistance and male preference in a stream-dwelling isopod: effects of female molt characteristics

In the stream-dwelling isopod, Lirceus fontinalis, mating contests between males and females occur prior to pair formation. We examined the relative contribution of male preference and female resistance to contest outcomes. We first quantified male and female behavior during typical mating interactions and examined the relationship between time until molt (TTM) and mating outcomes. We then examined the role of male preference and female resistance in determining mating outcomes when females differed in molt type (growth, egg deposition) and appeared to differ in TTM (due to hormone applications). Both male preference and female resistance contributed to different components of the mating sequence but female resistance ultimately determined whether or not pair formation occurred. Males expressed a preference for females that appeared to be close to molt, using variation in levels of molt hormone as a cue. However, males did not discriminate between females based on molt type. Received: 5 March 1999 / Received in revised form: 10 August 1999 / Accepted: 16 October 1999