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981.
982.
Jelica Lazarević Nikola Tucić Darka Šešlija Jovanović Josef Večeřa Dalibor Kodrík 《Insect Science》2012,19(3):303-314
Abstract The present study was aimed at revealing the responses of metabolite pools to selection for alternative reproductive schedules in the seed beetle, Acanthoscelides obtectus Say (Coleoptera: Chrysomelidae: Bruchinae). The levels of metabolites (free sugars, glycogen, lipids, soluble and hydrophobic proteins) that were determined in virgin females and males at three ages from adult eclosion onwards were compared among the base population (B) and two derived lines that were selected for either early (Y) or late (O) reproduction. The results showed differences in the accumulation of metabolites during pre‐adult development, as well as in the pattern of their changes during adult ageing. Generally, in comparison to the B population, the short‐lived beetles from the Y line showed increased protein content and reduced carbohydrate and lipid content, whereas the opposite was true for the long‐lived beetles from the O line. Females from the O line exhibited slower utilization of energy reserves and a slower increase in protein contents than females from the Y line. Females contained higher levels of free sugars, glycogen and hydrophobic proteins and lower levels of lipids and soluble proteins than males, although the sexual dimorphism was not evenly expressed among lines. Age‐specific changes in metabolite contents were slower in females than males. Our findings suggest that trade‐offs among capital resources are a physiological basis of early/late fitness trade‐offs and point to a conservation of resources that can be used for somatic maintenance. 相似文献
983.
Waynforth D 《Proceedings. Biological sciences / The Royal Society》2012,279(1731):1155-1160
There has been a recent increase in interest among evolutionary researchers in the hypothesis that humans evolved as cooperative breeders, using extended family support to help decrease offspring mortality and increase the number of children that can be successfully reared. In this study, data drawn from the 1970 longitudinal British cohort study were analysed to determine whether extended family support encourages fertility in contemporary Britain. The results showed that at age 30, reported frequency that participants saw their own parents (but not in-laws) and the closeness of the bond between the participant and their own parents were associated with an increased likelihood of having a child between ages 30 and 34. Financial help and reported grandparental childcare were not significantly positively associated with births from age 30 to 34. Men's income was positively associated with likelihood of birth, whereas women's income increased likelihood of birth only for working women with at least one child. While it was predicted that grandparental financial and childcare help would increase the likelihood of reproduction by lowering the cost to the parent of having a child, it appears that the mere physical presence of supportive parents rather than their financial or childcare help encouraged reproduction in the 1970 British birth cohort sample. 相似文献
984.
概述了江苏省有分布或栽培的木本药用植物资源,其中对主要种类20种的分布及药用功效进行了详细介绍,对其他木本药用植物的分布进行了简单的概述。近年来,越来越多的药用木本植物成为国内外研究者研究的重点对象。建议本省中医药工作者重视木本药用植物的药用价值的研究与开发。 相似文献
985.
Hamish S. Greig Pavel Kratina Patrick L. Thompson Wendy J. Palen John S. Richardson Jonathan B. Shurin 《Global Change Biology》2012,18(2):504-514
The exchange of organisms and energy among ecosystems has major impacts on food web structure and dynamics, yet little is known about how climate warming combines with other pervasive anthropogenic perturbations to affect such exchanges. We used an outdoor freshwater mesocosm experiment to investigate the interactive effects of warming, eutrophication, and changes in top predators on the flux of biomass between aquatic and terrestrial ecosystems. We demonstrated that predatory fish decoupled aquatic and terrestrial ecosystems by reducing the emergence of aquatic organisms and suppressing the decomposition of terrestrial plant detritus. In contrast, warming and nutrients enhanced cross‐ecosystem exchanges by increasing emergence and decomposition, and these effects were strongest in the absence of predators. Furthermore, we found that warming advanced while predators delayed the phenology of insect emergence. Our results demonstrate that anthropogenic perturbations may extend well beyond ecosystem boundaries by influencing cross‐ecosystem subsidies. We find that these changes are sufficient to substantially impact recipient communities and potentially alter the carbon balance between aquatic and terrestrial ecosystems and the atmosphere. 相似文献
986.
987.
988.
Landscape genomic approach to detect selection signatures in locally adapted Brazilian swine genetic groups 下载免费PDF全文
Robson Jose Cesconeto Stéphane Joost Concepta Margaret McManus Samuel Rezende Paiva Jaime Araujo Cobuci Jose Braccini 《Ecology and evolution》2017,7(22):9544-9556
Samples of 191 animals from 18 different Brazilian locally adapted swine genetic groups were genotyped using Illumina Porcine SNP60 BeadChip in order to identify selection signatures related to the monthly variation of Brazilian environmental variables. Using BayeScan software, 71 SNP markers were identified as FST outliers and 60 genotypes (58 markers) were found by Samβada software in 371 logistic models correlated with 112 environmental variables. Five markers were identified in both methods, with a Kappa value of 0.073 (95% CI: 0.011–0.134). The frequency of these markers indicated a clear north–south country division that reflects Brazilian environmental differences in temperature, solar radiation, and precipitation. Global spatial territory correlation for environmental variables corroborates this finding (average Moran's I = 0.89, range from 0.55 to 0.97). The distribution of alleles over the territory was not strongly correlated with the breed/genetic groups. These results are congruent with previous mtDNA studies and should be used to direct germplasm collection for the National gene bank. 相似文献
989.
Tanya Richardson 《Ethnos》2016,81(1):125-151
Between 1976 and 1980, a Soviet agro-industrial project turned the Sasyk estuary in southern Ukraine into a freshwater irrigation reservoir. While the project failed to produce irrigable water, it had many negative environmental consequences. Despite two decades of activism, this water body persists in its freshwater state. To understand how this situation persists, resources need to be conceived as materialities emergent in and distributed across assemblages of human and nonhuman elements rather than pre-existing substances. This move helps reveal a politics of multiplication that has enabled officials to sustain the resource potential of Danube–Dnister Irrigation System waters. As recognition of Sasyk as polluted and valueless increased, officials mobilized linkages that consolidated Sasyk as a fish reservoir, and its main canal as irrigable and drinking water, thereby stymieing activists' restoration campaign. 相似文献
990.
为检测家蚕(Bombyx mori)地方品种间的遗传差异,分析其遗传多样性和系统分化模式,为家蚕的品种鉴定和杂交育种亲本选择提供分子依据,本文对72个家蚕地方品种的淀粉酶基因(Bmamy2)片段进行测序,采用DNA序列分析技术探究了家蚕地方品种在核苷酸序列水平上的遗传差异及其系统分化特征.结果显示,家蚕地方品种在Bmamy2基因变异丰富,碱基突变率为5.6-8.2%,单倍型多样度为0.8294,核苷酸多样度为0.0236±0.00122,表明Bmamy2是一个具有丰富序列多样性的标记基因,能够较好地区分家蚕地方品种间的遗传多样性.系统发育分析、分子方差分析和Network分析等多种分析方法均检测到家蚕地方品种不按地理系统或生态类型聚类,各聚类种群均由来自不同地理系统或生态类型的品种构成,而来自同一地理系统或生态类型的品种则分别归属于不同的聚类种群.推测在家蚕的进化过程中并没有形成按地理系统或生态类型归类的分化格局,家蚕可能具有多种化性混合驯化起源的遗传背景和系统分化特征. 相似文献