eDNA metabarcoding of avocado flowers: ‘Hass’ it got potential to survey arthropods in food production systems?

In the face of global biodiversity declines, surveys of beneficial and
antagonistic arthropod diversity as well as the ecological services that
they provide are increasingly important in both natural and
agro-ecosystems. Conventional survey methods used to monitor these
communities often require extensive taxonomic expertise and are
time-intensive, potentially limiting their application in industries such
as agriculture, where arthropods often play a critical role in
productivity (e.g. pollinators, pests and predators). Environmental DNA
(eDNA) metabarcoding of a novel substrate, crop flowers, may offer an
accurate and high throughput alternative to aid in the detection managed
and unmanaged arthropod taxa (e.g. flower-visiting insects and potential
pollinators). Here, we compared the arthropod communities detected with
eDNA metabarcoding of flowers, from an agricultural species (Persea
americana - ‘Hass’ avocado), with two conventional survey techniques;
Digital Video Recording (DVR) devices and pan traps. In total, 80 eDNA
flower samples, 96 hours of DVRs and 48 pan trap samples were collected.
Across the three methods, 49 arthropod families were identified, of which
12 were unique to the eDNA dataset. Alpha diversity levels did not differ
across the three survey methods although taxonomic composition varied
significantly, with only 12% of arthropod families found to be common
across all three methods. This study demonstrates that eDNA metabarcoding
of flowers to detect visiting arthropods, although in a developmental
stage, can complement traditional survey methods and increase the
diversity of taxa detected with implications for both natural and
agro-ecosystems.