Airborne environmental DNA metabarcoding for the monitoring of terrestrial insects - a proof of concept

Abstract

Biodiversity is in decline due to human land use, exploitation, and climate change. To be able to counteract this alarming trend it is paramount to closely monitor biodiversity at global scales. Because this is practically impossible with traditional methods, the last decade has seen a strong push for solutions. In aquatic ecosystems the monitoring of species from environmental DNA (eDNA) has emerged as one of the most powerful tools at our disposal but in terrestrial ecosystems the power of eDNA for monitoring has so far been hampered by the local scale of the samples. In this study we report the first attempt to detect insects from airborne eDNA. We compare our results to two traditional insect monitoring projects (1) using light trapping for moth monitoring and (2) transect counts for the monitoring of butterflies and wild bees. While we failed to detect many of the same species monitored with the traditional methods, airborne eDNA metabarcoding revealed DNA from from six classes of Arthropods, and twelve order of Insects - including representatives from all of the four largest orders: Diptera (flies), Lepidoptera (butterflies and moths), Coleoptera (beetles) and Hymenoptera (bees, wasps and ants). We also recovered DNA from nine species of vertebrates, including frogs, birds and mammals as well as from 12 other phyla. We suggest that airborne eDNA has the potential to become a powerful tool for terrestrial biodiversity monitoring, with many impactful applications including the monitoring of pests, invasive or endangered species or disease vectors.

Airborne environmental DNA for terrestrial vertebrate community monitoring

“…Detection of locally occurring animals has also been documented in other studies on airborne eDNA. 19 , 33 This further highlights the potential of airborne eDNA for detection of wildlife. In addition, we detected fish (i.e., roach, smelt, and salmon) that are used as feed to various zoo animals on a daily basis.…”

BeeDNA: microfluidic environmental DNA metabarcoding as a tool for connecting plant and pollinator communities

“…The past decade has yielded remarkable technological advances to address the critical need to execute rapid, large-scale surveys of pollinators using metabarcoding (Elbrecht et al, 2019;Roger et al, 2021;Thomsen & Sigsgaard, 2019). More recently, microfluidic eDNA metabarcoding has enabled researchers to "cast a broader net" and compensate for taxonomic biases or blind-spots inherent to individual primer sets (Hauck et al, 2019).…”

“…Here, only one flower was sampled per plant, but plant-associated arthropods may not have interacted with this particular flower. Since this study was conceived, alternative strategies for eDNA detection of terrestrial insects have been successfully trialled, including eDNA aggregation via water (Valentin et al, 2020) and airborne eDNA (Roger et al, 2021). These approaches may circumvent the need for biological replication and invasive sampling of flowers, but require extensive validation against the current sampling strategies of swabbing flowers and/or whole flower harvest for pollinator eDNA used here and by Thomsen and Sigsgaard (2019).…”

“…However, the costs associated with development and application of single-species assays, coupled with increasing numbers of imperiled species requiring monitoring (especially pollinators), necessitates methods that can simultaneously screen for multiple taxa, increasing efficiencies and reducing financial burdens (L. R. Harper et al, 2018;Wilcox et al, 2020). eDNA metabarcoding may provide a solution for more comprehensive and less costly assessment of invertebrate communities across larger spatial and temporal scales (L. R. Mächler et al, 2019;Roger et al, 2021).…”

Sensitive environmental DNA (eDNA) methods to detect hemlock woolly adelgid and its biological control predators Leucotaraxis silver flies and a Laricobius beetle

“…If A. tsugae eDNA can be detected in rivers and streams, it could result in broader resolution sampling that could be followed up by targeted sampling to zero in on infestation. Recent advances in the development of air eDNA capture methodology may present an additional route to monitor the terrestrial insect community, including invasive species (Clare et al, 2021;Roger et al, 2022). With novel capture methods, advancements in on-site eDNA processing will allow surveyors to process eDNA samples within 30 min, as demonstrated in the case of invasive silver carp (Hypophthalmichthys molitrix Valenciennes) (Doi et al, 2020).…”