Spiders as natural DNA samplers can recover arthropod community
diversity and biotic interactions across space and time
Abstract
Global arthropod decline demands effective biodiversity monitoring
strategies. However, most current monitoring approaches do not provide
an exhaustive picture of arthropod community structure. In particular,
biotic interactions and temporal patterns of biodiversity change are
still poorly understood due to a lack of suitable monitoring approaches.
Here we explore the possibility of addressing these two shortfalls using
spiders, one of the most important predators of terrestrial arthropods,
as natural samplers for arthropod community DNA. We conducted several
experiments comparing the recovered community composition between spider
gut contents and traditional monitoring methods. Additionally, we used
archived spiders that were over a decade old to assess the preservation
of prey DNA in spiders over time. Spiders proved to be highly efficient
natural DNA samplers with gut content metabarcoding revealing similar
community composition and α- and β-diversity compared to metabarcoding
results of traditional methods. Unique arthropod taxa were detected by
spider gut contents and traditional methods respectively, indicating
that spider gut contents are not replacements but valuable complements
to traditional sampling. Besides providing an overview of local
diversity patterns, comparing gut contents across spider species
simultaneously generates an overview of trophic interactions and dietary
ecology in arthropod communities. Furthermore, well-preserved archived
spiders can effectively reconstruct historical diets, making them
valuable for studying past dietary diversity. Historical collections of
spiders thus constitute time capsules of spider dietary diversity.
Spider natural samplers can overcome critical shortfalls in biodiversity
monitoring and contribute to our future understanding of community
assembly across space and time.