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51.
新烟碱类农药呋虫胺对映体选择性研究进展 总被引:1,自引:0,他引:1
农业生产中,呋虫胺以外消旋体的形式销售和使用,在进入生态环境后出现对映体选择性降解、吸收、代谢、排泄等.不区分对映体间差异的传统风险评估给呋虫胺的合理使用与生态安全带来了诸多隐患.研究指出S-呋虫胺既是高毒体也是高活体,其生态毒性为R-呋虫胺的13.9~145.9倍,但R-呋虫胺也表现出较高的杀虫活性,且作物中优先降解,开发高比例的R体农药有利于维持杀虫活性的同时降低对非靶生物和生态环境的负效应.本文旨在综述呋虫胺对映体选择性生物活性、生态毒性及环境行为研究进展,为其科学难题的解决提供新思路,也为其科学有效管理提供理论依据. 相似文献
52.
运用质粒DNA评价法对澳门半岛的中山公园、高士德马路、氹仔岛的澳门大学3个采样点冬季PM10的氧化性损伤能力进行了研究.结果表明,3个采样点PM10的TD30值(引起30%超螺旋DNA损伤所需要的颗粒物的剂量)为中山公园采样点相对较低,其次是高士德马路采样点,澳门大学采样点最高,说明澳门半岛PM10的氧化性损伤能力大于氹仔岛.利用场发射扫描电镜及图像分析系统对颗粒物的微观形貌类型及粒度分布进行研究,并探讨了这些微观特征与颗粒物氧化性损伤能力之间的关系.结果表明,二次粒子和未知超细颗粒物的含量越高,TD30值越小,说明二次粒子和未知超细颗粒对大气颗粒物的氧化性损伤具有重要的作用.对比水溶样和全样的DNA评价结果得出,相同剂量下水溶样和全样对DNA的损伤量相似,说明大气颗粒物中的水溶组分是其氧化性损伤能力的主要来源. 相似文献
53.
Pheromone-based female mate choice and its effect on reproductive investment in a spitting spider 总被引:1,自引:0,他引:1
Teck Hui Koh Wee Khee Seah Laura-Marie Y. L. Yap Daiqin Li 《Behavioral ecology and sociobiology》2009,63(6):923-930
Numerous studies have focused on whether organisms can signal or perceive pheromones and use chemical signals in species and
mate recognition. Recently, there have been an increasing number of studies investigating whether pheromones are used in mate
choice. Yet, little attention has been paid in exploring the effects of pheromone-based mate choice on reproductive investment.
We first tested this hypothesis by providing virgin Scytodes sp. females with a choice between two virgin males in the presence of chemical signals alone and found strong evidence of
an odor-based mate preference. We then examined the consequences of the odor-based mate choice by allowing female Scytodes sp. that had previously made an odor-only mate choice to mate with preferred and non-preferred males, respectively. We measured
the success of copulation, mortality of male, pre-oviposition interval, egg-sac weight, egg weight, fecundity, fertility,
embryonic period, and size of offspring at hatching. Females that mated with the preferred males produced significantly heavier
egg sacs that contained more and larger eggs with a greater fertility. Significantly more non-preferred males than preferred
males were killed by spitting. However, pre-oviposition interval, embryonic period, and hatchling size were not affected by
female mate choice. This study is the first to demonstrate that female spiders are able to regulate their highly valuable
reproductive investment based solely on chemical signals. 相似文献
54.
55.
火灾常见有害燃烧产物的生物毒理 (Ⅱ )——一氧化氮、二氧化氮 总被引:5,自引:0,他引:5
火灾中有害燃烧产物对人的毒害是火灾致人伤亡的主要原因之一,本文详细论述了一氧化氮NO、二氧化氮NO2两种火灾常见有害燃烧产物的生物毒理,深入地揭示了火灾有害燃烧产物NO、NO2对生物体的损伤机理。 相似文献
56.
57.
In mammalian polygynous mating systems, male reproductive effort consists mainly of male–male competition and courting of
females, which entail substantial somatic costs. Males are thus expected to adjust their reproductive effort according to
their age and condition. In this study, we examined how activity budgets of male mountain goats (Oreamnos americanus), a polygynous ungulate, varied with age in a marked population over two periods: (1) summers 1995–2006 and (2) ruts 2004–2006.
We then assessed if the proportions of time spent in male–male competition and courtship behaviors were influenced by age-specific
body mass and social rank during the rut. Males spent most of their time foraging and resting during summer, and rested more
and foraged less with increasing age. During the rut, pronounced shifts in activity budgets occurred as juveniles (1–2 years)
increased time spent foraging, whereas adults (≥3 years) increased standing and time spent in social interactions at the expense
of foraging. At old age, reproductive effort either stabilized or decreased slightly, providing weak support for the ‘mating
strategy–effort’ hypothesis, predicting that courtship behaviors should peak in prime-aged males. Age-specific body mass did
not affect time spent in male–male competition, but was positively related with time spent in courtship behaviors, providing
support for the ‘individual quality’ hypothesis, predicting that males with more resources at the start of the rut should
spend more time in mating-related activities. Age-specific social rank did not affect reproductive effort. Surviving to prime
age while increasing mass each year should thus allow male ungulates to gain greater ability to court estrus females. 相似文献
58.
随着大量农药被广泛的使用并最终汇聚到环境介质中,对生态环境和人体健康产生潜在影响。秀丽隐杆线虫(Caenorhabditis elegans)是土壤中最丰富的后生动物,在土壤生态系统中具有重要地位,并作为一种重要的模式生物广泛应用于环境毒理学研究。本文从秀丽隐杆线虫常用的毒理学研究方法入手,以致死率、生长发育、运动行为、繁殖、活性氧自由基(ROS)水平、细胞凋亡水平、相关基因表达量和蛋白水平等作为测试指标,归纳总结农药对秀丽隐杆线虫的衰老性、神经及生殖系统的毒性效应,分析探索其毒性机理,并展望了未来的研究重点。 相似文献
59.
Karen J. Nutt 《Behavioral ecology and sociobiology》2007,61(11):1651-1663
Current mating system theory predicts that the number of females breeding in a group will depend on the number of females
in the group and the accessibility of unrelated males, whereas the number of males breeding in a group will depend on the
ability of males to control access to reproductive females. By combining information on group composition with genetic data,
I determined whether breeding patterns in a rock-dwelling rodent, Ctenodactylus gundi, were concordant with these expectations. C. gundi breeding patterns varied from facultative monogamy to uni-male polygyny to multi-male polygyny. The number of reproductive
individuals of each sex in a group increased with group size. Whereas communal breeding among related females tended to increase
female reproductive success, males breeding in the same group were unrelated to other group members and seemed to compete
over access to matings. While some males were assigned offspring from neighboring social groups, most group-living males successfully
monopolized the reproduction of females within their group. There was no evidence that females had multiply sired litters,
although some bred with alternative males in separate breeding attempts. Although numerous individuals were not assigned as
parents or offspring, genetic information enabled me to determine that most unassigned individuals were philopatric group
members, whereas only a few were unrelated immigrants into their current social group. Together, these results provide evidence
that C. gundi social groups represent fairly distinct reproductive units whose breeding patterns are dependent on group size and composition
in accordance with theoretical predictions.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
60.
Jan Komdeur 《Behavioral ecology and sociobiology》1994,34(3):175-186
Prebreeding Seychelles warblers (Acrocephalus sechellensis) frequently act as helpers on their natal territory, aiding in territory defence, predator mobbing, nestbuilding, incubation (only females) and feeding dependent young of their parents. In some cases helpers could attain breeding status (e.g. by joint-nesting) in their natal group and become co-breeders. Comparisons of group size and reproductive success on a given quality territory suggest that the presence of alloparents (helpers and cobreeders) significantly affects the reproductive success of their parents. The influence of alloparents on reproductive success was examined by removing alloparents from breeding units and comparing the success of natural-sized and artificially reduced groups. Removal experiments, controlled for territory quality, group size and breeder age, showed that the presence of one alloparent significantly improved the reproductive success of its parents. Analysis strongly suggests that this was entirely due to helping behaviour (i.e. providing care to offspring of their parents), thereby improving the helper's inclusive fitness benefits from staying at home. However, these experiments showed also that the presence of two or more alloparents in medium-quality territories significantly decreased reproductive success, compared with groups with one alloparent. Several lines of evidence suggest that this may have been due to the joint-nesting and reproductive competition that could occur in breeding groups, or simply to resource depression when a large number of previous offspring remained on their natal territory. 相似文献