Insect biomass shows a stronger decrease than species richness along urban gradients

1. Anthropogenic land cover change is a major driver of biodiversity loss, with urbanisation and farmland practices responsible for some of the most drastic modifications of natural habitats. The relative importance of different land covers for shaping insect communities, however, is unclear. 2. This study examines the effect of urban and farmland covers, along with land cover heterogeneity, at a landscape scale on species richness, evenness and biomass of flying insects using citizen science carnet sampling across Denmark. 3. Increasing urban cover had a negative effect on insect richness but an even stronger negative effect on biomass. Increased land cover heterogeneity did not mitigate the negative effect of urban cover. Insect assemblages also became more even with increased urban cover. Farmland cover had no significant effect on insect richness, evenness or biomass. 4. Based on our findings, the urban cover has a strong negative impact on insect communities, indicating that urbanisation could contribute to insect declines. Moreover, our findings indicate that insect loss occurs more through loss of biomass than loss of species, which may affect the ecosystem-level consequences of urbanisation

Detecting flying insects using car nets and DNA metabarcoding

Monitoring insects across space and time is challenging, due to their vast taxonomic and functional diversity. This study demonstrates how nets mounted on rooftops of cars (car nets) and DNA metabarcoding can be applied to sample flying insect richness and diversity across large spatial scales within a limited time period. During June 2018, 365 car net samples were collected by 151 volunteers during two daily time intervals on 218 routes in Denmark. Insect bulk samples were processed with a DNA metabarcoding protocol to estimate taxonomic composition, and the results were compared to known flying insect richness and occurrence data. Insect and hoverfly richness and diversity were assessed across biogeographic regions and dominant land cover types. We detected 15 out of 19 flying insect orders present in Denmark, with high proportions of especially Diptera compared to Danish estimates, and lower insect richness and diversity in urbanised areas. We found 319 species not known for Denmark and 174 species assessed in the Danish Red List. Our results indicate that the methodology can assess the flying insect fauna at large spatial scales to a wide extent, but may be, like other methods, biased towards certain insect orders.Statistical analyses were carried out in RStudio on the original samples (size sorted samples were merged prior to analysis). Scripts can be found here: https://github.com/CecSve/InsectMobile_CarNet. The data in this Dryad repository are the data used in script 02. Funding provided by: Aage V. Jensens FondeCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100002721Award Number:Flying insects were collected with car nets during June 2018 in Denmark. Citizen scientists drove back and forth on 5 km routes and the insects were shipped to the Natural History Museum of Denmark in 96% EtOH. The insects were size sorted in two size fractions prior to DNA extraction with a non-destructive DNA lysis buffer and further processing with a DNA metabarcoding protocol. The full laboratory protocol for the research project 'InsectMobile' can be accessed here: https://dx.doi.org/10.17504/protocols.io.bmunk6ve. Only the output of fwh primer pair is used in this study

Low-dose hydrocortisone in patients with COVID-19 and severe hypoxia: The COVID STEROID randomised, placebo-controlled trial.

BACKGROUND In the early phase of the pandemic, some guidelines recommended the use of corticosteroids for critically ill patients with COVID-19, whereas others recommended against the use despite lack of firm evidence of either benefit or harm. In the COVID STEROID trial, we aimed to assess the effects of low-dose hydrocortisone on patient-centred outcomes in adults with COVID-19 and severe hypoxia. METHODS In this multicentre, parallel-group, placebo-controlled, blinded, centrally randomised, stratified clinical trial, we randomly assigned adults with confirmed COVID-19 and severe hypoxia (use of mechanical ventilation or supplementary oxygen with a flow of at least 10 L/min) to either hydrocortisone (200 mg/d) vs a matching placebo for 7 days or until hospital discharge. The primary outcome was the number of days alive without life support at day 28 after randomisation. RESULTS The trial was terminated early when 30 out of 1000 participants had been enrolled because of external evidence indicating benefit from corticosteroids in severe COVID-19. At day 28, the median number of days alive without life support in the hydrocortisone vs placebo group were 7 vs 10 (adjusted mean difference: -1.1 days, 95% CI -9.5 to 7.3, P = .79); mortality was 6/16 vs 2/14; and the number of serious adverse reactions 1/16 vs 0/14. CONCLUSIONS In this trial of adults with COVID-19 and severe hypoxia, we were unable to provide precise estimates of the benefits and harms of hydrocortisone as compared with placebo as only 3% of the planned sample size were enrolled. TRIAL REGISTRATION ClinicalTrials.gov: NCT04348305. European Union Drug Regulation Authorities Clinical Trials (EudraCT) Database: 2020-001395-15