Cover Picture and Issue Information

This month’s cover image shows a bumblebee (Bombus sp.) on a flower in Princeton, New Jersey (US). Simulation studies have suggested that to achieve enough statistical power to detect community‐wide declines and/or positive responses to agri‐environment remedies, large‐scale monitoring programmes for bees will require identifying at least hundreds of thousands of bees to species level. Morphology‐based taxonomy is infeasible at this scale, and amplicon‐based methods (‘metabarcoding’) are prone to false positives and negatives, as well as being unable to provide estimates of species biomass or counts. In this issue, Tang et al. apply metagenomic methods to the assessment of bee biodiversity. It is now feasible to assemble hundreds of mitochondrial genomes from insect species, allowing the efficient creation of comprehensive reference databases. As a result, mass bee samples can be shotgun sequenced on high‐throughput Illumina sequencers, and the resulting reads mapped to reference mitogenomes. Tang et al. ’s pilot study shows that species detection is highly reliable, even for morphologically cryptic species. Moreover, read frequencies are correlated with estimated bee species biomasses, allowing estimates of species counts via a combination of occupancy across traps and estimated biomasses within traps. Mitogenomic methods for biodiversity assessment can be straightforwardly scaled up to hundreds of taxa or more per sample (e.g. ‘all pollinating insects + parasites’) by building up reference databases and increasing sequencing depth. Photo credit for this picture © Xin Zhou