Hormonal correlates of reproductive status in the queenless ponerine ant, Streblognathus peetersi

In colonies of the queenless ant Streblognathus peetersi, dominance interactions produce a reproductive hierarchy in which one individual, the alpha, is capable of producing offspring while her subordinates remain infertile. Based on differences between behaviour and cuticular hydrocarbon profiles, the subordinates can be further divided into high and low ranking workers. Although it had been shown previously that alphas treated with a juvenile hormone analog lose their reproductive status, little was known of the endocrinological basis of dominance in this species. To elucidate the underlying endocrinology of these three ranks, we measured the individual in vitro rate of juvenile hormone (JH) production of excised corpora allata, and the ecdysteroid titer of pooled hemolymph samples. Production of JH was highest in low-ranking workers, intermediate in high rankers, and almost undetectable in alphas. Ecdysteroid titers were low for low rankers, but were more than twice as high for both high rankers and alphas. The results support the hypothesis that JH suppresses ovarian function in these queenless ants, and suggest that ecdysteroids may be responsible for stimulating vitellogenin production. The possible role of these hormones as behavioural modulators is also discussed.     

水库鲢鳙鱼生长状况的评价预测

一.引言一般生物受许多环境因素的约束和作用。我们根据有关生物学理论、专家意见和调查材料,结合河北省抚宁县洋河水库现状材料和拟议中筹建的河北省青龙县桃林口水库建库后水质、生态环境的预测,应用层次分析法和综合评定法,对上述两水库的鲢、鳊鱼生长状况.进行评价和预测。     

基于灾害风险综合指标的陕西省农业干旱时空特征

随着气候变化,农业干旱直接威胁粮食安全.本文以陕西省为研究对象,基于自然灾害风险理论,综合考虑干旱灾害影响因素,从致灾因子的危险性、承灾体的暴露性、环境的脆弱性和地区的抗旱能力4个风险要素选取指标,采用层次分析法确定指标权重,构建自然灾害风险综合指标,分析2009—2013年陕西省农业干旱时空特征.结果表明: 研究期间,陕北地区农业干旱风险略呈下降趋势;陕南地区呈急剧升高态势,以商洛市为甚;关中地区基本稳定,以咸阳市最高、西安市最低.陕西省农业干旱风险大体呈现从南向北逐渐递增现象.     

FAHP ranking and selection of pretreatment module for membrane separation processes in textile cluster

Recent development in membrane manufacturing and extensive application of membranes in effluent treatment has opened up a new water resource. The effluent pretreatment module plays a critical role in membrane performance. Appropriate selection of conventional and advanced pretreatment modules in membrane separation processes (MSP) is significant to the success of zero effluent discharge (ZED). This study addresses performance assessment of eight conventional and advanced pretreatment modules implemented for wastewater management in a textile cluster in South India. The comparative pollutant reduction, capital, operation and maintenance (OM) cost of pretreatment modules are discussed. The ranking and interdependence of the pretreatment modules were analyzed through fuzzy analytical hierarchy process (FAHP) with MATLAB software.The pretreatment module IV ranked third with a composite weight of 15.46%. The integrated study of performance assessment and FAHP resulted in an optimum pretreatment module IV comprising the sequence of chemical precipitation, bio-oxidation processes (activated sludge processes) followed by chemical precipitation, to achieve the ZED. This study provides a techno-economically feasible solution for selection of an effective pretreatment module for MSP in the textile cluster.     

The alpha factor and the conquest of Mexico: A study in ethological history

“Alpha behavior” affected human politics and social organization during the sixteenth-century conquest of Mexico by Spanish imperialists. The behavior of Spanish conquistadores is compared to that of other primates in the well-known studies of Jane Goodall and Frans de Waal. Parallels between Spanish and Aztec behavior are also noted so as to identify the shared patterns of behavior that cross human cultures and may be called primate universals. One of these universals is the alpha factor. It administers the social order through the ability to balance benevolence and brutality in order to maintain coalitions and the loyalty of subordinates. The alpha factor is expressed through display behaviors that vary with culture, but all cultures, including those of chimpanzees and bonobos, build around it. It may be tempered by the presence of female coalitions or of a bonobo alpha female, but it is a visible focal point of a society, thereby making display a necessary part of leadership.     

Size-dependent variation of gender in high density stands of the monoecious annual,Ambrosia artemisiifolia (Asteraceae)

Summary We examined the relationship between size variability and the distribution of functional gender in stands of the monoecious, wind-pollinated annual Ambrosia artemisiifolia. Populations of 60 individuals were grown in the greenhouse at a density of 372 m^–2 and at two nutrient levels. Among the surviving plants, after self-thinning, variability in above-ground biomass and gender was higher in the high nutrient treatment. Among individuals there was a significant positive correlation between maleness and both height and biomass. Fecundity was also positively correlated with both measures of size. Based on the pattern of distribution of male and female flowers within the plant, it appears that the increase in maleness in larger plants is due to increased branching and axis elongation. These results demonstrate that competitive interactions, which lead to increased variability in biomass and fecundity, can also generate variability in gender within populations.     

Clone dynamics,population dynamics and vegetation pattern ofGlaux maritima on a Baltic sea shore meadow

The vegetative propagation ofGlaux maritima is correlated with growth habit which is inturn related to the light environment. Plant form and vegetative behaviour were recorded 1980–1984 and an attempt to correlate this to population dynamics and vegetation development was made.The type of vegetative propagation gives rise to a size hierarchy of propagules and thus a strong within clone dynamics. A range of life stages may be permanently present in a clone. Clones from different parts of a shore meadow have different patterns of vegetative propagation. The offshoot growth behaviour can be used to explain vegetation patterns and neighbour relationships.