A sampling strategy for genome sequencing the British terrestrial arthropod fauna

The Darwin Tree of Life (DToL) project aims to sequence and assemble high-quality genomes from all eukaryote species in Britain and Ireland, with the first phase of the project concentrating on family-level coverage plus species of particular ecological, biomedical or evolutionary interest. We summarise the processes involved in (1) assessing the UK arthropod fauna and the status of individual species on UK lists; (2) prioritising and collecting species for initial genome sequencing; (3) handling methods to ensure that high-quality genomic DNA is preserved; and (4) compiling standard operating procedures for processing specimens for genome sequencing, identification verification and voucher specimen curation. We briefly explore some lessons learned from the pilot phase of DToL and the impact of the Covid-19 pandemic

Causal inference and large‐scale expert validation shed light on the drivers of SDM accuracy and variance

Aim: To develop a causal understanding of the drivers of Species distribution model (SDM) performance. Location: United Kingdom (UK). Methods: We measured the accuracy and variance of SDMs fitted for 518 species of invertebrate and plant in the UK. Our measure of variance reflects variation among replicate model fits, and taxon experts assessed model accuracy. Using directed acyclic graphs, we developed a causal model depicting plausible effects of explanatory variables (e.g. species' prevalence, sample size) on SDM accuracy and variance and quantified those effects using a multilevel piecewise path model. Results: According to our model, sample size and niche completeness (proportion of a species' niche covered by sampling) directly affect SDM accuracy and variance. Prevalence and range completeness have indirect effects mediated by sample size. Challenging conventional wisdom, we found that the effect of prevalence on SDM accuracy is positive. This reflects the facts that sample size has a positive effect on accuracy and larger sample sizes are possible for widespread species. It is possible, however, that the omission of an unobserved confounder biased this effect. Previous studies, which reported negative correlations between prevalence and SDM accuracy, conditioned on sample size. Main conclusions: Our model explicates the causal basis of previously reported correlations between SDM performance and species/data characteristics. It also suggests that niche completeness has similarly large effects on SDM accuracy and variance as sample size. Analysts should consider niche completeness, or proxies thereof, in addition to sample size when deciding whether modelling is worthwhile

The vulnerability of British aquatic insects to climate change

Freshwater ecosystems are particularly at risk from climate change due to the intrinsic link between the physical properties of the water environment and those species that live there. Mayflies, stoneflies and caddisflies are key indicators of the health of freshwater environments and their biological traits and ecological preferences determine their vulnerability to climate change. Traits and preferences for 289 British species were analysed, with voltinism, length of flight period, altitudinal preference and affinity to headwaters being the main factors causing vulnerability. Sixteen species were deemed to be at risk from climate change. These species are distributed across Great Britain, but particular hotspots of vulnerability are present in upland areas. These areas should be targeted with mitigation measures to reduce the impacts of climate change on populations of aquatic insects

Urban Biodiversity: Successes and Challanges: Brownfields: oases of urban biodiversity

Volume: 25Start Page: 29End Page: 3

The genome sequence of the black needle fly, Leuctra nigra (Olivier, 1811) [version 1; peer review: 2 approved]

We present a genome assembly from an individual male Leuctra nigra (black needle fly; Arthropoda; Insecta; Plecoptera; Leuctridae). The genome sequence is 536.3 megabases in span. Most of the assembly is scaffolded into 13 chromosomal pseudomolecules, including the X sex chromosome. The mitochondrial genome has also been assembled and is 17.6 kilobases in length

Torix Rickettsia are widespread in arthropods and reflect a neglected symbiosis.

BackgroundRickettsia are intracellular bacteria best known as the causative agents of human and animal diseases. Although these medically important Rickettsia are often transmitted via haematophagous arthropods, other Rickettsia, such as those in the Torix group, appear to reside exclusively in invertebrates and protists with no secondary vertebrate host. Importantly, little is known about the diversity or host range of Torix group Rickettsia.ResultsThis study describes the serendipitous discovery of Rickettsia amplicons in the Barcode of Life Data System (BOLD), a sequence database specifically designed for the curation of mitochondrial DNA barcodes. Of 184,585 barcode sequences analysed, Rickettsia is observed in ∼0.41% of barcode submissions and is more likely to be found than Wolbachia (0.17%). The Torix group of Rickettsia are shown to account for 95% of all unintended amplifications from the genus. A further targeted PCR screen of 1,612 individuals from 169 terrestrial and aquatic invertebrate species identified mostly Torix strains and supports the "aquatic hot spot" hypothesis for Torix infection. Furthermore, the analysis of 1,341 SRA deposits indicates that Torix infections represent a significant proportion of all Rickettsia symbioses found in arthropod genome projects.ConclusionsThis study supports a previous hypothesis that suggests that Torix Rickettsia are overrepresented in aquatic insects. In addition, multiple methods reveal further putative hot spots of Torix Rickettsia infection, including in phloem-feeding bugs, parasitoid wasps, spiders, and vectors of disease. The unknown host effects and transmission strategies of these endosymbionts make these newly discovered associations important to inform future directions of investigation involving the understudied Torix Rickettsia

International scientists formulate a roadmap for insect conservation and recovery

Plant science