Temporal changes of Collembola population and alterations of life history parameters and acetylcholinesterase and superoxide dismutase activities in Cyphoderus javanus (Collembola) as biomarkers of fly ash pollution in lateritic soil

Fly ash is applied in agricultural fields to improve soil quality and crop yield; however, there are concerns regarding environmental hazards and toxicity to ecologically important soil organisms. The soil microarthropod fauna is a vital component of detritus food web, and major groups like Collembola are sensitive indicators of soil quality; however, information is scanty on their biomarker potentials against xenobiotics in tropical soils. The present study was aimed to evaluate temporal changes of Collembola population in fly ash amended field plots, and assess the biomarker potentials of life history parameters and biochemical responses such as acetylcholinesterase (AChE) and superoxide dismutase (SOD) activities in Cyphoderus javanus Borner (Collembola, Insecta), exposed to fly ash treated soil in microcosms. The field study using 5% (50 t ha^?1) and 20% (200 t ha^?1) doses of fly ash revealed dose-dependent and persistent decline in the density and relative abundance of Collembola population in sandy loam lateritic soil. The microcosm experiments showed negligible lethal effect of fly ash on C. javanus, but major life history parameters namely survival success, fecundity, and molting were significantly inhibited by fly ash treatments. The activity of AChE was downregulated, whereas activity of SOD was upregulated within 7 days of exposure of C. javanus to fly ash treated soil. These biological and biochemical parameters in Collembola are potential biomarkers, and therefore, the effects of fly ash are significant in C. javanus, an ecologically relevant species in the tropical soils of India.     

中国5种土壤跳虫对重金属镍的毒性响应

为了研究镍(Ni~(2+))对不同种类跳虫的毒性效应,将曲毛裸长(Sinella curviseta)、四刺泡角(Ceratophysella duplicispinosa)、小原等节(Proisotoma minuta)、茉莉花长角(Entomobrya sp.)、符氏直棘(Orthonychiurus folsomi)5种中国优势跳虫物种,在琼脂培养基环境下分别暴露于Ni~(2+)的8个浓度组中进行24 h、72 h-LC_(50)急性毒性试验和28 d生存试验。利用Bliss法测得其5种跳虫的24 h-LC_(50)分别为52.99、35.91、33.46、23.72、13.50 g·L~(-1);72 h-LC_(50)为46.25、4.54、13.37、14.79、4.35 g·L~(-1)。在28d生存试验中得到成虫存活数量和繁殖情况。结果表明,5种跳虫中曲毛裸长对镍有较强的耐受性,茉莉花长角和小原等节次之,四刺泡角和符氏直棘较弱。符氏直棘与四刺泡角相比,随时间增加对镍的耐受性有相对增强的趋势。此外,Ni~(2+)对跳虫的毒性影响表现出阶段性的阈值效应。Ni~(2+)对5种跳虫的繁殖均有抑制作用。     

Phylogeny of Collembola based on cuticular compounds:inherent usefulness and limitation of a character type

The phylogeny of Collembola, originally discussed from a morphological point of view, has more recently benefited from novel insights brought by molecular analyses. Both morphological and molecular characters produced a well-resolved phylogenetic hypothesis including all orders, most families, and a large number of genera. However, several conflicting points exist between molecular and morphological data, and new characters are clearly needed to resolve these inconsistencies. In this study the usefulness of a new character type not previously used in the phylogenetic study of Collembola was tested: the epicuticular chemical compounds. Our phylogenetic analysis was based on 380 compounds from 26 Collembola species. The results show good resolution for terminal branches but not for internal nodes. This is probably due to the partial involvement of epicuticular lipids in ecological functions such as water conservation and sexual attraction. Thus, this character type is appropriate for reconstructing phylogenetic relationships among recently diversified groups. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.