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1. Larval success was compared when one, two, or three egg clutches were laid in kumquat fruits (≈ 10 ml in volume) either successively on the same day or at the rate of one clutch per day. 2. Increased clutch density was associated with a significant decrease in larval survival rate and non‐significant decreases in larval growth rate and pupal mass. 3. Larval and pupal parameters showed significantly larger variance when clutches were laid on successive days than on the same day, suggesting a competitive advantage for older larvae over younger larvae. 4. The results suggest that, in small fruit, reduced fitness due to larval competition may act against possible fitness benefits due to social facilitation among adult females, hence reducing the likelihood of non‐linear population dynamics caused by processes such as the Allee effect. 相似文献
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The anatomy of the arthropod Squamacula clypeata Hou and Bergström, 1997 from the Lower Cambrian Chengjiang Lagersta¨tte is redescribed based on four newly excavated specimens. The new material was collected from localities recently discovered in the Kunming area, Yunnan Province, south-west China, and preserves remarkable details of the ventral morphology, revealed by preparation. Squamacula clypeata is dorsoventrally flattened and rounded in outline. The cephalon was covered by a wide, short shield, with a large doublure and a pair of uniramous antennae on the ventral side. The thorax consists of nine somites, each protected by a tergite and carrying at least one pair of biramous limbs. The pygidium is covered with a small rounded tergum. The endopod is segmented, equipped with short spines on the inner margin of the coxa and a claw-like structure distally, and the exopod flap-like, fringed with setae. The limbs in the pygidium are like those in the thorax in shape. Squamacula was most probably a nektobenthic predator. The spinose endopod could walk, grasp and grind. The large flap-like exopod was adapted for swimming and respiration. Its affinities lie with the Arachnomorpha, but the relationships with other known taxa remain ambiguous. 相似文献
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使用冷冻方法防治昆虫标本虫害 总被引:5,自引:0,他引:5
皮蠹幼虫对昆虫标本的蛀蚀是我国北方地区标本保藏时需要注意的首要问题。经12次的试验观察表明,花斑皮蠹幼虫TrogodermavariabileBallion在冰柜中放置位置不同其冷冻致死率亦不相同置于冰柜表层的,死亡率介于0~50%;上层的死亡率为95%~100%;中上层及中层死亡率达100%。放置在表层及上层的皮蠹幼虫,在经2d以上的冷冻处理后部分个体出现复活。因此,对那些原先放置上层及表层的标本,第1次冷冻结束后,间隔数天应再进行第2次冷冻,以提高和巩固冷冻杀虫效果。经3年的实践证明,采用冷冻方法治理皮蠹幼虫为害效果明显,可以推广普及。 相似文献
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中国水仙(Narcissus tazetta var.chinensis)的组织培养 总被引:12,自引:0,他引:12
以栽培的中国水仙Narcissus tazetta var.Chinensis鳞茎为实验材料,采取“无液处理”的简捷方法获取外植体,并筛选出中国水仙离体鳞茎培养的最佳培养基。 相似文献
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基因组规模代谢网络模型构建及其应用 总被引:1,自引:0,他引:1
微生物制造产业的发展迫切需要进一步提高认识、设计和改造微生物细胞代谢的能力,以推动工业生物技术快速发展。随着微生物全基因组序列等高通量数据的不断积聚和生物信息学策略的持续涌现,使全局性、系统化地解析、设计、调控微生物生理代谢功能成为可能。而基于基因组序列注释和详细生化信息整合的基因组规模代谢网络模型(GSMM)构建为全局理解和理性调控微生物生理代谢功能提供了最佳平台。以下在详述GSMM的应用基础上,描述了如何构建一个高精确度的GSMM,并展望了未来的发展方向。 相似文献
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Jian Liu Shi-Chu Liang Feng-Hong Liu Ren-Qing Wang Ming Dong 《Diversity & distributions》2005,11(4):341-347
Plant invasions have been attracting increasing attention from ecologists because of their worldwide environmental impacts and huge economic costs. Research on the characteristics of the recipient regions is essential for understanding the process of plant invasion. However, few previous studies on invasibility of habitats include social factors, although human activities are critical in the process of plant invasion. China is a vast country with high plant species diversity and a long history of introduction of exotic plant species and is particularly vulnerable to invasive plant species. Alien plant species are widespread in the country. Therefore, the study of invasive plants in China is urgent in practice and theoretically important for developing invasion ecology. For the present study, 126 species were selected to represent the major invasive plant species in China. We then collected data on their species richness in 31 provincial administrative units of China and performed Spearman rank correlations between species richness and possible natural and socio‐economic factors. We found that socio‐economic factors, such as human density and GDP, correlated positively with the species richness of invasive plants in China. In conjunction with the natural and socio‐economic correlations in the study of regional distribution pattern of the major invasive plants, we discussed the factors influencing the regional distribution pattern of the major invasive plants in China. We suggest that native plant species richness was mainly determined by the natural conditions of the regions, while invasive species richness was influenced by natural conditions and human disturbance together. 相似文献
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5种光合细菌种间原生质体融合及优良农用融合子的筛选鉴定 总被引:3,自引:0,他引:3
处于对数生长期的光合细菌球形红假单胞菌(Rhodopseudomonassphaeroides)、沼泽红假单胞菌(Rhodopseudomonaspalustris)、嗜酸红假单胞菌(Rhodopseudomdnasacidophila)、深红红螺菌(Rhodospirarubrum)、万尼氏红微菌(Rhodomocrobiumvannielii),经溶菌酶(3mg/L)处理50min后,获得了它们的菌体形成的原生质体,其再生率分别为80%、71%、82%、61%、74%.取等量的亲本菌株在35%的PEG(MW6000)诱导下两两融合5min,共10种组合.其融合率为球×沼2.5×10-4、球×嗜2.1×10-4、球×深2.0×10-4、球×万2.1×10-4、沼×嗜2.8×10-4、沼×深2.4×10-4、沼×万2.6×10-4、嗜×深2.0×10-4、嗜×万2.3×10-4、深×万2.4×10-4.经影印法鉴定:形成的融合子可以分别生长于以相应的有机物为唯一碳源的培养基上,所有融合子体积均相当于两亲本株体积之和,融合子菌落形态特征介于两亲本株之间.从中随机挑选100个融合子,以辣椒苗作为靶标植物,从上述融合子中筛选到了1株具有显著促进作物生长、提高抗病性的融合子. 相似文献