Comparison of Polyethylene Bubble Wrap and Corrugated Cardboard Traps for Sampling Tree-Inhabiting Spiders

In this paper, we studied the use of polyethylene bubble wrap and corrugated cardboard bark traps to sample spiders inhabiting tree trunks, with special reference to test whether they function the same way despite the differences in the spider community imposed by the different tree species and surroundings and times of sampling. The survey was carried out from July 1997 to July 1998 in Turin, Italy, in a green urban area on three poplars and four American basswoods. Differences between the two methods were tested in terms of abundance, diversity, dominance, mean body length of specimens, and proportion of juveniles, calculating Spearman's correlations. Three-factor analysis of variance, multiresponse permutation procedure, and indicator species analysis were used for further analysis. Results obtained by the two traps were correlated following a similar trend over sampling time. Bubble polyethylene seemed to be more effective than corrugated cardboard at trapping higher number of specimens. The dimension and total amount of interstices and the different microhabitat conditions of temperature and humidity seemed to be the main factors influencing spider composition in terms of the selected variables. On the basis of our results, polyethylene bark traps are recommended for sampling spiders living on trees. It is important to consider seasonality in experimental design, autumn being the period with the highest abundance of spiders but a lower level of diversity

Looking back, looking forward: a review of the new literature on diatom teratological forms (2010–2020)

AbstractOver the last years, issues concerning diatom teratological forms and environmental stress have received growing interest within the scientific community. Publications on this topic dated back to 1890 and were summarized in a review published in 2009 by the journalHydrobiologia, accounting for high citation rates (i.e. 117 citations Scopus and 232 citations Google Scholar, October 2020). This wide interest stimulates the authors to further unravel teratological forms significance in the light of the most recent publications (2010–2020). Diatom teratological forms are one of the best individual-level biomarkers since they provide a rapid response to several environmental stressors, including new emerging pollutants. The mechanisms involved in teratological valve likely involve both cytoskeleton and silicon metabolic pathway impairments. However, teratologies do not seem to weaken the reproduction capacity and viability of the affected individuals. We recognized eight types of teratologies as involving different parts of the valve, depending on genus. In order to summarize the information obtained by several years of research, we suggest a four-step procedure aimed at providing a theoretical pathway that researchers should follow to better explain results obtained in next-future studies and representing a starting point for the development of an environmental index based on teratological forms