Pollination syndromes ignored: importance of non-ornithophilous flowers to Neotropical savanna hummingbirds

Generalization prevails in flower–animal interactions, and although animal visitors are not equally effective pollinators, most interactions likely represent an important energy intake for the animal visitor. Hummingbirds are nectar-feeding specialists, and many tropical plants are specialized toward hummingbird-pollination. In spite of this, especially in dry and seasonal tropical habitats, hummingbirds may often rely on non-ornithophilous plants to meet their energy requirements. However, quantitative studies evaluating the relative importance of ornithophilous vs. non-ornithophilous plants for hummingbirds in these areas are scarce. We here studied the availability and use of floral resources by hummingbirds in two different areas of the Cerrado, the seasonal savannas in Central Brazil. Roughly half the hummingbird visited plant species were non-ornithophilous, and these contributed greatly to increase the overall nectar availability. We showed that mean nectar offer, at the transect scale, was the only parameter related to hummingbird visitation frequency, more so than nectar offer at single flowers and at the plant scale, or pollination syndrome. Centrality indices, calculated using hummingbird–plant networks, showed that ornithophilous and non-ornithophilous plants have similar importance for network cohesion. How this foraging behaviour affects reproduction of non-ornithophilous plants remains largely unexplored and is probably case specific, however, we suggest that the additional energy provided by non-ornithophilous plants may facilitate reproduction of truly ornithophilous flowers by attracting and maintaining hummingbirds in the area. This may promote asymmetric hummingbird–plant associations, i.e., pollination depends on floral traits adapted to hummingbird morphology, but hummingbird visitation is determined more by the energetic "reward" than by pollination syndromes.     

Biogenic amine levels, reproduction and social dominance in the queenless ant Streblognathus peetersi

Social harmony often relies on ritualised dominance interactions between society members, particularly in queenless ant societies, where colony members do not have developmentally predetermined castes but have to fight for their status in the reproductive and work hierarchy. In this behavioural plasticity, their social organisation resembles more that of vertebrates than that of the “classic” social insects. The present study investigates the neurochemistry of the queenless ant species, Streblognathus peetersi, to better understand the neural basis of the high behavioural plasticity observed in queenless ants. We report measurements of brain biogenic amines [octopamine, dopamine, serotonin] of S. peetersi ants; they reveal a new set of biogenic amine influences on social organisation with no common features with other “primitively organised societies” (bumble bees) and some common features with “highly eusocial” species (honey bees). This similarity to honey bees may either confirm the heritage of queenless species from their probably highly eusocial ancestors or highlight independent patterns of biogenic amine influences on the social organisation of these highly derived species.     

Prehibernating aggregations of Polistes dominulus: an occasion to study early dominance assessment in social insects

At a very early age several mammals establish a first dominance hierarchy, which often persists into adulthood. Social wasps offer an excellent opportunity to study such a phenomenon in insects. Indeed, foundresses of several paper wasps meet in clusters to hibernate from September to March. In spring, wasps found new associative nests where linear hierarchies occur. In the first phase of hibernation, clustering Polistes dominulus wasps show most of the social interactions occurring on the nest 6 months later. At the emergence from diapause, some females already show some behavioral and physiological traits typical of dominant individuals. Here, we investigated the significance of the interactions in the autumnal clusters. We demonstrated that in a given pair, it is more likely that the dominant wasp in autumn becomes the alpha female in spring after the nest foundation phase occurred. Moreover, we showed that dominant females in clusters have both larger body size and ovaries. As ovarian development mainly depends on the social context, our findings seem to indicate that social factors affect the tendency to dominate in aggregations. Furthermore, we suggest that some females may reinforce their physiological status by dominating in clusters, thus increasing the probability to become dominant in spring.     

哑铃湾网箱养殖自身污染状况

根据2002年4月、7月、10月和2003年1月对哑铃湾海域网箱养殖区的调查数据，分析该海域网箱养殖自身污染情况。结果表明，网箱养殖增加了水体中N、P的含量，改变了养殖水体中一些化学因子的垂直分布，加速了哑铃湾海域的有机污染和富营养化。随着养殖年限的增加，哑铃湾网箱养殖自身污染日趋严重。     

我国生物质废物污染现状与资源化发展趋势

我国的生物质废物具有产生量大、可降解有机物含量高的特点,如果能对其进行有效的利用,不但能减少污染,还将会有助于缓解我国能源短缺的现状。介绍了我国生物质废物的污染现状及生物质废物资源化的主要途径,指出我国生物质废物资源化中存在的问题,并提出今后的发展方向及发展对策。     

厦门港浮游植物磷胁迫状况研究

通过检测碱性磷酸酶活性(APA)及相关理化因子,研究2002～2004年间,厦门港浮游植物的P生理状态的变化。结果表明,厦门港总APA变化范围0.92～9.50 nmol/(L.h),在不同的季节及区域,浮游植物遭受不同程度的P胁迫。厦门外港的年平均APA高于西港和浔江港,表明浮游植物遭受的P胁迫程度较深。在厦门港赤潮爆发时,P将成为浮游植物进一步生长繁殖的限制因子。     

大亚湾典型生态系统状况调查与分析

大亚湾典型生态系统状况调查表明:过度捕捞,乱捕及违禁捕捞使大亚湾水产资源大幅下降,传统的渔汛早已不复存在;岸线、海滩过度开发、非法盗猎、航道阻隔、海域环境污染和诸多人为误捕、滥杀和破坏产卵环境等原因,大亚湾绿海龟的生存环境受到严重威胁;港口开发和水下爆破等致使珊瑚礁群落的优势种发生改变及石珊瑚出现白化现象;大型海岸工程的建设和过度对滩涂的围垦养殖,导致大亚湾红树林多以小簇或单株零散分布,红树林生态系统已处于一种极不健康的状态;大亚湾地区的滨海湿地面积逐年减少,人工湿地面积逐渐增大,天然湿地林相退化严重,湿地的外貌和结构日趋简单,降低了湿地生态和环境的功能.     

铁岭市生态环境现状及保护对策

通过对铁岭市生态环境的现状调查和分析，总结了铁岭市生态环境存在的问题及其成因，提出了生态环境保护的对策。     

中国核电发展现状及趋势

<正>2013年我国煤炭产量高达37亿吨,是世界煤炭产量的一半。在我国煤炭消费量中,一半用于发电,产生了大量二氧化碳和温室气体,严重污染环境。近年来,我国频发大面积雾霾天气,对生态环境和人民群众的健康造成了严重危害。因此,大力发展清洁能源是我国经济可持续性发展、改善环境、提高人民生活质量的必然选择和迫切要求。核能是一种安全、经济和清洁的能源,核能和平利用是上世纪人类最伟大的发明之一。自1954年世界第一个核电     

浅议南通市海洋环境保护现状及对策

根据多年的环境监测结果,分析了南通海洋环境保护的现状.结果表明,南通海域的环境污染主要是因为陆源排污、围填海工程以及过度的捕捞与养殖.针对南通海洋环境的实际情况,提出了一些解决的对策和建议.     

大连湾海水环境质量状况分析

根据大连湾1997年11月水质调查资料，对该湾20世纪90年代末海域环境质量状况进行了分析，大连湾水域主要污染物为无机氮和活性磷酸盐，东部的环境质量好于西部，其中臭水厌附近有机污染及富营养化严重，环境质量日趋恶化。与90年代初相比，湾内部分水域无机氮及活性磷酸盐含量有所提高。应根据海域纳污能力，实际陆源污染物排海总量控制。     

大亚湾养殖区营养盐状况分析与评价

研究了1997年春季大亚湾大鹏澳海域及1997～1998年度和1998～2000年春季澳头海域营养盐及其他水化参数的变化。大鹏澳和澳头海域平均DIN含量分别为52.37、115.07μg/L,DIP为5.33、9.19μg/L,DSi为351.81、1068.3μg/L。大鹏澳海域营养状态质量指数(NQI)值多在1.0以下,平均0.97;1998～2000年春澳头海域NQI平均值分别为1.94、1.63、1.51。从1997年澳头海域水质状况来看,春夏季节水质污染程度较高,秋冬季节较低。研究结果表明:大亚湾海域整体水质良好,而且大鹏澳海域水质优于澳头海域,但近岸海区和养殖区已受到一定程度的污染,水质已接近中营养型水平。     

珠江口海洋倾倒区现状与存在问题讨论

通过对珠江口海洋倾倒区现状的分析,揭示珠江口在海洋倾倒区存在的问题,探讨泥沙运动格局对海洋环境自然平衡的影响,提出海洋倾倒区规划要注意的问题.