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321.
José Martín Emilio Civantos Luisa Amo Pilar López 《Behavioral ecology and sociobiology》2007,62(2):173-179
Evidence for parasite-mediated sexual selection has been found in many species that use visual ornaments to attract females.
However, in many animals, variation in female responses to scents of parasitized males suggests that parasitic infections
might also affect information conveyed by pheromones (i.e., chemical ornaments). Thus, pheromones might also function in parasite-mediated
sexual selection. We show here that female lizards Psammodromus algirus responded differently to femoral gland secretions of males according to the parasite load and health of these males. Scents
of healthier males elicited more tongue flicks (a chemosensory behavior) by females, suggesting that these scents were more
attractive. Chemical analyses showed that parasite load and the T-cell-mediated immune response were related to the variability
in the proportions of some lipids in secretions of males. Further trials testing the chemosensory responses of females to
chemical standards indicated that females actually discriminated the chemicals related to males’ health from other chemicals
found in secretions. We suggest that these chemical ornaments may provide reliable information on the health and degree of
parasitic infection of a male. 相似文献
322.
农村产业结构调整问题研究 总被引:2,自引:0,他引:2
姚阳 《湖南环境生物职业技术学院学报》2006,12(1):65-68
本文首先对农村产业结构调整的相关概念进行了阐述.其次,分析和归纳了判断农村产业结构合理化的标准以及农村产业结构变动的影响因素. 相似文献
323.
Carmen?Rossini Alexander?Bezzerides Andrés?González Maria?Eisner Thomas?EisnerEmail author 《Chemoecology》2003,13(4):199-205
Summary. Evidence is presented that pyrrolizidine alkaloid acquired
by Utetheisa ornatrix (Lepidoptera, Arctiidae) as a larva
from Crotalaria foodplants is incorporated in part into the scales
of the adult. A single forewing of a male or female moth may contain in
the order of 6 to 13 g monocrotaline in its scale cover or about 1 to 2%
of the moths systemic monocrotaline content. Based on estimates of the number
of scales per forewing, the monocrotaline content of individual scales is calculated
to be in the order of 0.1 and 0.2 ng monocrotaline per male and female scale,
respectively. This amounts to concentrations of about 1 and 3%, values roughly at
a par with the average systemic concentration (0.5-0.6%) previously determined
for monocrotaline in Utetheisa. It is argued that the presence of pyrrolizidine alkaloid
in the moths scale coating could account for the promptness with which adult Utetheisa are
rejected by spiders. It is suggested further that chemical impregnation of scales with substances
deterrent to predators may be more widespread among insects than generally assumed. 相似文献
324.
纳滤膜处理高浓度废液分离规律研究 总被引:3,自引:1,他引:3
利用管式或卷式纳滤膜处理废弃母液,在固定工艺条件下,透过液通量与浓缩时间呈一定数学关系;当浓缩进行到最后,透过液中的COD浓度会突然提高,该突然下降时间应长连续浓缩时间,抗生素截留率的变化规律基本与COD的去除率相同,但数值不同。利用COD的变化规律基本可以确定抗生素的变化趋势。 相似文献
325.
Toshiharu Akino 《Chemoecology》2002,12(2):83-89
Summary. The myrmecophilous beetles, Zyras comes (Staphylinidae) and Diaritiger fossulatus (Pselaphidae) are guests of the black shining ant Lasius fuliginosus. Host worker ants never attacked these beetles, and often gave regurgitant to Z. comes following tactile communication with the beetle. By contrast, the workers from colonies without the myrmecophiles showed
hostile responses towards Z. comes before tactile contact, but were not aware of D. fossulatus until contact. In L. fuliginosus, workers within a colony shared profiles, but the profiles differed among colonies. GC analyses showed that both Z. comes and D. fossulatus beetles had the same hydrocarbons as L. fuliginosus, and the profiles were more similar to those of the host colony workers than the foreign workers. Both Z. comes and D. fossulatus appear to imitate the hydrocarbon profile of their host workers, allowing integrating into the host nest. A Y-maze bioassay
indicated that Z. comes can follow the trail pheromone of L. fuliginosus. This suggests that Z. comes may detect other chemical signals of L. fuliginosus to keep closer interactions with the workers.
Received 22 June 2001; accepted 12 November 2001. 相似文献
326.
Summary. Pyrrolizidine alkaloids (PAs) present a model system in the investigation of tritrophic interactions mediated by plant secondary compounds. However, their toxicity for insect herbivores has never been experimentally proven. Here, we demonstrate the toxic effects of a PA on growth and survival of the eri silk moth Philosamia ricini. In a feeding experiment, larvae of this generalist herbivore fed with an artificial PA diet gained weight significantly slower than control animals, and died as pupae. We suggest that derivatives of the ingested PA N-oxide damage developmental functions during metamorphosis. A tracer test with [14C]senecionine N-oxide revealed that the caterpillars lack adaptations that would prevent conversion of the chemical into the pro-toxic free base. In contrast, the PA adapted leaf beetle Longitarsus anchusae accumulates PAs as N-oxides. We tested the purpose of sequestration in this species as defence against predators. Through a series of prey choice experiments with three carabid predator species, chemically non-protected bark beetle pupae were chosen almost uniformly over L. anchusae pupae. In a following choice test with one of these predators, artificially PA-treated mealworm segments deterred the predator from feeding. Overall the study corroborates the immediate toxic effect of PAs on non-adapted herbivores and the protective effect that adapted insects may gain by sequestering them. It thereby underlines the potential for PAs to play a central role in multitrophic interactions between plants, phytophages and their predators. 相似文献
327.
In this study two sites were selected in order to investigate groundwater contamination and spatial relationships among groundwater quality, topography, geology, landuse and pollution sources. One site is the Asan area, an agricultural district where pollution sources are scattered and which is mainly underlain by granite of Cretaceous age. The other site is the Gurogu area of Seoul city, an industrial district where an industrial complex and residential areas are located and which is mainly underlain by gneiss of Precambrian age. Groundwater samples collected from these districts were analysed for chemical constituents. An attribute value files of chemical constituents of groundwater and the spatial data layers were constructed and pollution properties were investigated to establish out spatial relationships between the groundwater constituents and pollution sources using geographic information systems (GIS).Relatively high contents of Si and HCO3
– in the groundwater from the Asan area reflect the effect of water–rock interaction whereas high contents of Cl–, NO3
– and Ca2+ in the groundwater from the Gurogu area are due to the pollution of various sources. The significant seasonal variation of SiO2, HCO2
– and Ca2+ contents, and that of Ca2+ content were observed in the Asan and the Gurogu areas, respectively. Seasonal variation of pollutants such as Cl–, NO3
– and SO4
2– was not observed in either area. Pollution over the critical level of the Korean drinking water standard has been investigated from 15 sampling sites out of 40 in the Asan area, and 33 sampling sites out of 51 in the Gurogu area. Pollution by NO3
–, Cl–, Fe2+, Mn2+, SO4
2– and Zn2+ in the groundwater from the industrial district (Gurogu area) and that of NO3
, SO4
2– and Zn2+ in the groundwater from the agricultural district (Asan area) were observed. The principal pollutant in both areas is NO3
–. Deep groundwater from the Asan area is not yet contaminated with NO3
– except for one site, but most of the shallow groundwater site occurring near the potential point sources is seriously contaminated. From the result of buffering analysis, it seems clear that factories and stock farms are the principal pollution sources in the Asan area. The groundwater from the Gurogu area has already been seriously polluted considering the fact of NO3
– contamination of deep groundwater. Chlorine pollution of shallow groundwater in the Gurogu area was also observed. Spatial relationship between pollution level and its source was clarified in this study by using GIS, which will be applicable to the effective management of groundwater quality. 相似文献
328.
化学纤维栅湿式除尘是一种复合机理的新型湿式过滤除尘技术,其过滤风速为2~10m/s,阻力仅为200~500Pa,除尘效率达到99.62%,能很好解决矿山溜井卸矿产生的粉尘,使溜井含尘气流经净化后达到新鲜风流卫生标准。 相似文献
329.
姚寿福 《长江流域资源与环境》1998,7(3):198-204
长江上游沿江产业带是一个资源富集,开发潜力巨大的区域,既是长江产业带的重要组成部分,也是西南地区经济发展的重心地带。区域经济的快速发展有赖于区域产业结构的有序演进。本文在分析长江上游沿江产业带产业结构演进背景-产业基础,经济基础,资源基础和宏观环境的基础上,根据国外产业结构演进手一般经验,对本区产业结构演进的历史进程和目前所处阶段进行了分析和判定。 相似文献
330.
用改良彗星试验检测工业废水的DNA损伤作用 总被引:2,自引:0,他引:2
采用改良彗星试验直接检测了多种工业废水不所引起的V79细胞DNA损伤。结果表明,所测的种各工业废话水均含有DNA损伤剂,能够诱发培养的V79细胞DNA链断裂,其中以制革厂不的DNA损伤作用最强。本研究显示出改良彗星试验在综合评价各种废水遗传毒性方面具有广阔的应用前景。 相似文献